Conditions: Delirium
Keywords: analgesics cardiac surgery sedation
Allocation: RANDOMIZED | Intervention model: FACTORIAL
Enrollment: 140
Healthy volunteers: no

Brief summary:
Investigators will assess the incidence and duration of postoperative delirium in patients ≥60 years old undergoing coronary artery bypass grafting (CABG), with/without valve surgery (aortic and/or mitral) based on different regimens for postoperative sedation and analgesia. Patients will receive either intravenous (IV) dexmedetomidine and IV acetaminophen or standard postoperative management using IV propofol with morphine or hydromorphone. The Confusion Assessment Method (CAM) will be used to assess delirium in these patients. Investigators also seek to compare postoperative (48 hours) analgesic requirements in patients with or without IV acetaminophen. Investigators will finally assess postoperative cognition in post-surgical patients up to one year post-discharge using a cognitive assessment scale.

Detailed description:
This is a prospective, randomized, placebo-controlled, triple-blinded, factorial design study consisting of 120 patients who were randomized and received a study intervention. Intravenous dexmedetomidine and acetaminophen will be compared to the standard sedation/analgesic propofol and opioid regimen.

After obtaining informed consent, study subjects will be randomized by an unblinded investigator and receive a specific combination of both sedatives and analgesic medications. Sedatives will include either IV propofol or IV dexmedetomidine, and analgesics IV acetaminophen or placebo (100 mL 0.9% NaCl equivalent to the administered volume of IV acetaminophen). Subjects will be allocated in a 1:1:1:1 fashion into the following four treatment arms: 1. IV acetaminophen with IV propofol, 2. IV acetaminophen with IV dexmedetomidine, 3. IV propofol with placebo, or 4. IV dexmedetomidine with placebo. Sedation and analgesia protocols will begin while patients are in the OR and continue as they are transferred to the Cardiovascular Intensive Care Unit (CVICU). The medications for sedation will be weight based (loading infusion of 0.5 - 1 µg/kg given over 10 minutes followed by a maintenance infusion of 0.1-1.4 µg/kg/hr for IV dexmedetomidine, or 20-100 µg/kg/min for IV propofol). Postoperative sedation is administrated 4-6 hours before patients are woken up in the CVICU. IV Acetaminophen (1g or 100mL) will be given every 6 hours for 48 hours to patients randomized to this drug. The volume of the placebo will be administered in respective groups in the same timeframe. Oral acetaminophen will be continued until discharge in all patients. All groups will also receive bolus doses of opioids (IV morphine or hydromorphone) as needed for breakthrough pain.

Patients will be administered a preoperative (baseline) and a series of post-operative evaluations to assess delirium by a blinded investigator. Baseline assessments will include the Montreal Cognitive Assessment (MoCA), days of the week (DOW), months of the year (MOY), Delirium Symptom Interview (DSI), the Geriatric Depression Scale (GDS) and the Confusion Assessment Method (CAM). Daily cognitive assessments will include the DSI, CAM, and a standard cognitive assessment. At discharge, the MoCA, DOW, MOY, DSI, and CAM will be given. Follow-up assessments will be conducted at 1 month and 1 year post-discharge and will include the telephonic MoCA, DSI, GDS and CAM. The delirium research assessments will not be provided to the treating clinicians. Treating clinicians will assess and treat delirium as usual, including assessment and correction of reversible causes, behavioral management, and use of IV haloperidol as needed for agitation. Rescue doses of haloperidol will be recorded in the study.

Blood will be collected from all subjects at the time of the baseline assessment, post-operation day 1 (POD1) while in ICU, POD 2 in the ICU, and within 48 hours of discharge. Two sets of 10 mL will be collected at each time point, with a total of 80mL of blood per patient. Efforts will be made to efficiently draw blood through the patient's arterial line at baseline or add onto to scheduled draws with phlebotomy. The plasma and buffy coat will be separated from the blood, aliquoted into labeled vials, and stored in a biomarker bank at -80°C for future use.

Arms:
arm 1: 20-100 µg/kg/min IV propofol given for 4-6 hours before the patients are woken up in the ICU

1g IV acetaminophen every 6 hours for 48 hours during the first 2 days postoperatively arm 2: A loading infusion of 0.5 - 1 µg/kg given over 10 minutes will be administered. After the loading infusion, a maintenance infusion of 0.1-1.4 µg/kg/hr will be initiated.

1 g IV acetaminophen every 6 hours for 48 hours during the first 2 days postoperatively arm 3: 20-100 µg/kg/min IV propofol given for 4-6 hours before the patients are woken up in the ICU Volume of the placebo (saline) will match that of IV acetaminophen at 100ml 0.9% NaCl. arm 4: 0.1-1.0 µg/kg/hour IV dexmedetomidine given for 4-6 hours before the patients are woken up in the ICU Volume of the placebo (saline) will match that of i.v. acetaminophen at 100ml 0.9% NaCl.

Interventions: intervention 1: IV acetaminophen & IV propofol intervention 2: IV acetaminophen & IV dexmedetomidine intervention 3: IV propofol & placebo intervention 4: IV dexmedetomidine & placebo
Intervention descriptions: intervention 1: use of IV tylenol and IV propofol for pain and sedation (respectively) intervention 2: use of IV tylenol and IV dexmedetomidine for pain and sedation (respectively) intervention 3: use of IV propofol for sedation and morphine, the drug of choice for cardiac pain intervention 4: use of IV dexmedetomidine for sedation and morphine, the drug of choice for cardiac pain

Protocol document:
Prot_SAP_000.pdf: 
Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
 
SUPPLEMENTARY APPENDIXES 
Contents 
eAPPENDIX 1. STUDY PROTOCOL AND STATISTICAL ANALYSIS PLAN ................................................ 
eAPPENDIX 2. FAST TRACK PROTOCOL AND INTRAVENOUS DRUG ADMINISTRATION 
GUIDELINES .................................................................................................................................................. 
REFERENCES ................................................................................................................................................ 
 
 
This supplementary material has been provided by the authors to give readers additional information 
about their work. 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
2 
 
 
 
eAPPENDIX 1. STUDY PROTOCOL AND STATISTICAL ANALYSIS PLAN   
 
 
 
Principal Investigator:  
Balachundhar Subramaniam, MD, MPH  
Study Sponsor: 
Mallinckrodt Pharmaceuticals 
 
Study Coordinating Center: 
Beth Israel Deaconess Medical Center 
Original Protocol Version Date: 
01/29/2015 
IRB Protocol Number:   
 
2014P000413     
Clinicaltrials.gov NCT:  
 
NCT02546765  
 
STUDY PROTOCOL 
Purpose    
The goal of this randomized clinical trial is to evaluate the effect of intravenous (IV) acetaminophen vs 
placebo, combined with IV propofol vs dexmedetomidine, for postoperative sedation and analgesia 
respectively, in adult patients 60 years or older undergoing coronary artery bypass grafting (CABG) or 
combined CABG/valve surgeries to assess the incidence of postoperative delirium with the Confusion 
Assessment Method (CAM or CAM-ICU). It is possible that there may be a benefit to those enrolled in the 
dexmedetomidine and acetaminophen group, as their incidence of delirium could possibly be reduced, 
however we cannot guarantee this. 
Additionally, this study will assess postoperative cognition following cardiac surgery through 1-year using a 
cognitive assessment scale and compare postoperative analgesic requirements in patients with and without 
IV acetaminophen. 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
3 
 
 
 
Study Summary  
 
Title  
Effect of Postoperative Intravenous Acetaminophen versus Placebo, 
Combined with Propofol or Dexmedetomidine, on Postoperative In-
Hospital Delirium Among Older Patients Following Cardiac Surgery: The 
DEXACET Randomized Clinical Trial 
Objective 
 
 
To evaluate the effect of postoperative IV acetaminophen (paracetamol) 
vs placebo, combined with IV propofol vs dexmedetomidine, on 
postoperative delirium among older patients undergoing cardiac surgery 
Inclusion Criteria 
Patients 60 years or older undergoing CABG with or without aortic and/or 
mitral valve replacement requiring cardiopulmonary bypass  
Exclusion Criteria 
Patients with preoperative left ventricular ejection fraction (LVEF) <30%, 
pre-existing cognitive impairment, Alzheimer’s disease, Parkinson’s 
disease, medications for cognitive decline, history of recent seizures, 
serum creatinine 2 mg/dL, liver dysfunction, recent history of alcohol 
abuse, English language limitations, hypersensitivity to study medications, 
and undergoing emergent surgery 
Study Design 
Single center, randomized, triple blind, placebo controlled, factorial design 
clinical trial 
 
Patients were randomized to one of four factorial groups which included 
randomization to receive postoperative analgesia with intravenous 
acetaminophen or placebo every 6 hours for 48 hours. In addition, patients 
were randomized to receive postoperative sedation starting at chest 
closure and continued for up to 6 hours postoperatively or until extubation 
with intravenous dexmedetomidine or propofol.  
 
The incidence of postoperative in-hospital delirium was assessed daily 
using the CAM or CAM-ICU during the patient’s hospitalization. In addition, 
follow up assessments were conducted at one month and one year.   
Study Discontinuation  
Patient request or any serious adverse event thought to be related to study 
procedures 
Key Roles 
 
Principal Investigator: Balachundhar Subramaniam, MD MPH 
  
Institution: Beth Israel Deaconess Medical Center, Boston MA 
 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
4 
 
 
 
Significance and Background    
Approximately 50% of patients have postoperative delirium following cardiac surgery1.  The growing body 
of evidence suggests that in-hospital delirium is associated with poor hospital outcomes, including a tenfold 
increased risk of death, and a fivefold increased risk of nosocomial related complications2.   Delirium has 
also been associated with serious longer term outcomes such as poor functional recovery, and most 
recently, impaired cognitive function for up to one year after cardiac surgery3. Importantly, intervenable 
factors, such as perioperative sedation and analgesia with opioids may contribute to the etiology of delirium.  
In the setting of cardiac surgery done increasingly in older patients, there is an urgent need to test 
alternative sedation and complementary analgesic techniques.  
Dexmedetomidine, a selective alpha-2 receptor agonist, provides sedation without causing respiratory 
depression. Dexmedetomidine is also suggested to have an opioid sparing effect that makes it a unique 
sedative drug.  Currently used sedation drugs (midazolam) release deliriogenic mediators through binding 
of Gamma-aminobutyric Acid (GABA) receptors.  Dexmedetomidine has no effect on the GABA receptors. 
Although these characteristics suggest dexmedetomidine to be a unique and promising drug for sedation 
following cardiac surgery, its efficacy on reducing the incidence, duration and long term effects of delirium 
has not been studied thoroughly. 
Studies involving use of dexmedetomidine in an attempt to reduce the incidence of delirium in cardiac 
surgical patients provide conflicting results. One meta-analysis concluded that dexmedetomidine in cardiac 
surgery shortened the ventilator time (but not the Intensive Care Unit (ICU) or hospital length of stay), 
reduced the incidence of postoperative ventricular arrhythmias and delirium in cardiac surgical patients4. 
However, there are several issues with this meta-analysis, particularly for the systematic assessment of 
postoperative delirium. The problems with the four studies that formed the basis of this meta-analysis are 
explained in the next few paragraphs. 
In a retrospective study5 of administrative database from 250 hospitals, the incidence of postoperative 
delirium following cardiac surgery was significantly decreased with associated cost savings in the 
dexmedetomidine group.  This study compared two regimens (dexmedetomidine, propofol plus narcotics 
vs. propofol vs. narcotics). Propofol was used in the dexmedetomidine group as well.  This trial specifically 
does not mention how delirium was assessed in individual hospitals.   
A randomized controlled trial6 comparing dexmedetomidine/propofol to morphine/propofol in cardiac 
surgery patients showed a decreased duration of delirium (5 days to 2 days) in the dexmedetomidine group.  
This study found a similar incidence of delirium in both the groups.  Propofol was used as a sedative in both 
the groups and this could have attributed to similar incidences of delirium in both the groups.  There is a 
possibility the study was not powered adequately as the baseline incidence of delirium in the control group 
was a surprisingly low 15%, much lower than other cardiac surgery studies that have employed state-of-
the art delirium measures. This study used CAM-ICU for assessing delirium both in intubated and extubated 
patients.  While the CAM-ICU, a delirium assessment that does not require any verbal responses by the 
patient, is state-of-the-art for intubated patients, it has reduced sensitivity for delirium in verbal patients.  
This design could have underestimated the incidence of delirium.   
The third study7 included in the meta-analysis was a prospective, randomized, open labeled trial comparing 
three groups (dexmedetomidine, midazolam, and propofol). This study reported a dramatically decreased 
incidence of delirium in the dexmedetomidine group, 3%, compared to 50% in propofol and midazolam 
groups. This was a small study, with only 118 patients were recruited and only 90 patients finally analyzed, 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
5 
 
 
 
with 28 patients randomized patients excluded for protocol violations.  This introduces a significant selection 
bias.  Furthermore, a 94% reduction in the incidence of delirium was seen in this study.  This effect size is 
almost implausibly large and has not been seen in other studies.  Nevertheless, this study can provide a 
framework for sample size for future studies assuming the best case scenario.   
The final study8 included in the meta-analysis was a prospective randomized control trial of 89 patients 
undergoing non emergent CABG.  In this study, a patient satisfaction questionnaire was used to assess 
pain, comfort and extubation process between intravenous dexmedetomidine and propofol groups.  One 
patient in each group was reported to have delirium. This study was not designed to identify patients with 
delirium with any specific tools such as CAM and thus could have grossly underestimated delirium 
incidence.  Thus, the meta-analysis represents a combination of poorly designed studies with differing 
measurements, and is extremely unlikely to create a significant impact or practice change among clinicians.  
Therefore, these findings will not result in a practice change in cardiac surgical intensive care units. 
Postoperative pain following cardiac surgery can be due to the sternal incision, chest tube sites and leg 
incisions.  Current pain relief strategy includes postoperative opioid administration (IV morphine or 
hydromorphone).  While, inadequate pain relief increases the risk of postoperative delirium, opioids with 
their psychoactive properties also increase the risk of postoperative delirium, especially in elderly patients.  
A multimodal balanced postoperative pain management is advantageous and provides several beneficial 
effects.  The options in cardiac surgery would include nonsteroidal anti-inflammatory drugs and 
acetaminophen.  Their postoperative use decreases the exposure of older patients to opioids and can be 
an effective delirium prevention strategy.  Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) have 
contraindications after many kinds of surgery, including cardiac surgery, which include their deleterious 
effects on the gastrointestinal tract and renal function.   
Acetaminophen has no psychoactive properties and is an attractive option as it lacks bleeding risks 
associated with nonsteroidal agents.  Acetaminophen is for the most part safe but could cause liver 
dysfunction in rare instances.  Oral administration of acetaminophen achieves limited blood levels in 
critically ill patients and therefore has limited efficacy. IV acetaminophen addresses this by allowing 
administration in critically ill patients and providing superior bioavailability to oral preparations9. This 
approach has been shown to reduce pain intensity and also decrease the rescue intravenous morphine 
used during the postoperative period.   
IV acetaminophen has never been studied in the context of cardiac surgery and delirium prevention.  
Additionally, comparing IV acetaminophen as an adjuvant analgesic in combination with IV propofol or IV 
dexmedetomidine may ascertain additive or synergistic effects on delirium prevention. Our randomized, 
single-blind, pre-pilot study with 12 patients showed that in patients who received IV acetaminophen as 
adjuvant analgesic (N=6), the incidence of delirium was 17% (1/6) compared to 67% (4/6) in those who did 
not.  The total incidence was 42% (5/12).  Despite the small sample size, this provocative finding suggests 
that IV acetaminophen with propofol or dexmedetomidine may offer a significant benefit in reducing the 
incidence of delirium following cardiac surgery.  If this benefit is proved in a larger study as proposed, this 
will have a significant impact in patient care and satisfaction. 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
6 
 
 
 
Subject Recruitment  
Screening  
Eligible participants will be identified at preadmission testing clinic appointments, in the cardiac 
catheterization lab or on the medical floors. At this time all inclusion and exclusion criteria will be assessed.  
Inclusion Criteria  
Adult patients ≥ 60 years of age who are undergoing CABG with/without valve (aortic and/or mitral) 
procedure requiring bypass.   
Exclusion Criteria  
Patients will be excluded if they had a preoperative LVEF <30% emergent procedure, isolated aortic 
surgery, pre-existing cognitive impairment, Parkinson’s disease, Alzheimer’s disease, prophylactic 
medications for cognitive decline, active history of drug or alcohol abuse, serum creatinine >2mg/dL , liver 
dysfunction, non-English speaking, seizures in the last three months, emergent procedure or  
hypersensitivity to study drugs or procedures.   
 
Adult patients unqualified or incapable of giving legal consent will be excluded. 
Informed Consent  
Written informed consent will be obtained prior to initiation of any study-specific procedures. Consent will 
be obtained by one of the participating researchers of the study. At the time of consent, all study procedures 
will be explained in detail, including the associated risks and benefits.  The subjects will have the opportunity 
to ask any and all questions, and will be reminded that participation is voluntarily. All subjects will be 
consented with curtains drawn or the door closed, assuring patient privacy.  Written informed consent will 
then be obtained from interested participants. The original signed form will remain with the investigator in 
the study file.  Copies will be given to the patient and filed in the official medical record as well.   
Randomization and Blinding  
After obtaining written informed consent, participants will be randomized to one of four groups by the 
research pharmacy using a sequence of computer –generated random numbers. Blocked randomization 
will be used to assign recruited participants to one of four combinations of analgesics and sedatives in a 
1:1:1:1 allocation: (1) acetaminophen and dexmedetomidine, (2) acetaminophen and propofol, (3) placebo 
and dexmedetomidine, or (4) placebo and propofol. In order to blind the patient, the care team, and the 
research staff assessing outcomes to the analgesia group, 1 gram of IV acetaminophen and placebo (0.9% 
saline) were distributed in equal volume IV bags. Due to the distinct appearance of propofol, there was no 
blinding to the sedation group. 
Study Procedures  
Overview  
The proposed study is a randomized, placebo controlled, factorial design, triple blind, clinical trial designed 
to evaluate the effect of postoperative IV acetaminophen versus placebo, combined with IV propofol versus 
dexmedetomidine, on postoperative delirium among older patients undergoing cardiac surgery. Patients 
will be randomized to one of four groups (1) acetaminophen and dexmedetomidine, (2) acetaminophen and 
propofol, (3) placebo and dexmedetomidine, or (4) placebo and propofol. It is possible that the participants 
who receive acetaminophen and dexmedetomidine may benefit from the study as their incidence of delirium 
could possibly be reduced, however we cannot guarantee this.  


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
7 
 
 
 
Study Groups 
The four treatment arms will be:  
1. Acetaminophen and dexmedetomidine 
2. Acetaminophen and propofol 
3. Placebo and dexmedetomidine 
4. Placebo and propofol 
 
All study medications will be administered intravenously and doses will be weight-based. 
Acetaminophen/placebo will be administered on ICU transfer and thereafter every six hours for a total of 
eight doses. Volume of the placebo (saline) will match that of IV acetaminophen at 100ml 0.9% sodium 
chloride.  Acetaminophen administration in any form other than the blinded study medication during this 
time was not allowed. Propofol or dexmedetomidine was started during chest closure and continued for up 
to six hours postoperatively or until extubation, whichever occurred first. Participants in the 
dexmedetomidine groups will get a bolus dose of 0.5 - 1mcg/kg IV during chest closure, followed by a 
maintenance infusion of 0.1 -1.4 mcg/kg/hour. Propofol infusions will be avoided in these participants. 
Patients in the propofol groups will receive propofol at a dose of 20 – 100 mcg/kg/min and dexmedetomidine 
infusions will be avoided in these patients.  
Pharmacy 
Once a participant is enrolled, the study team will contact the research pharmacy to randomize the subject. 
The research pharmacy at Beth Israel Deaconess Medical Center will be responsible for preparation and 
distribution of study medications. Study team members will physically deliver the first dose of the 
acetaminophen/placebo (saline) medication. Subsequently the research pharmacy will be responsible for 
delivering the study medication to the ICU. Any unused drug will be returned to the research pharmacy for 
disposal.   
Study Assessments  
The assessments will be completed at specific time points.  Once consent is obtained, a trained study team 
member blinded to treatment allocation will proceed with a baseline cognitive and delirium assessment. 
This will include the assessment of cognitive function using the Montreal Cognitive Assessment (MoCA), 
supplemented with days of the week backwards (DOWB) and months of the year backwards (MOYB) for 
additional attention testing, the Delirium Symptom Interview (DSI) to capture symptoms of delirium and the 
Geriatric Depression Scale (GDS) to assess for baseline depression.  Using data from the cognitive testing 
and DSI, a study team member will complete the Confusion Assessment Method (CAM), which includes a 
diagnosis of delirium using the CAM diagnostic algorithm.  This detailed assessment will take no more than 
20-30 minutes.  Every day, a study team member will administer a standard cognitive assessment and the 
CAM. These daily assessments will take approximately 10-15 minutes.  On the day of discharge, the MoCA 
with DOW and MOY, the DSI, and CAM will be completed.  (If the discharge assessment was performed in 
anticipation of discharge on a specific day but the discharge was delayed (i.e. logistical reasons, clinical 
reasons), this will not be considered a protocol deviation.)  A follow-up assessment will be administered at 
1 month and 1 year post-discharge over the telephone and will include a telephone version of the MoCA 
known as the T-MoCA, DSI, GDS, and CAM.  Assessments will be administered and scored by trained 
study team members.  
If daily assessments are negative for three consecutive days (i.e. days 5, 6 & 7), they will then be completed 
every other day until date of discharge. In addition, these assessments will be done at the patient’s convenience 
to ensure ability to finish the evaluations. The table below outlines the assessments at various time points.  


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
8 
 
 
 
 
 
 
 
 
Baseline 
Daily 
Discharge 
1 month 
1 year 
Assessments 
 
 
 
 
 
Montreal Cognitive Assessment (MoCA) 
with Days of the week (DOW) & Months 
of the year (MOY) 
X 
 
X 
 
 
Delirium Symptom Interview (DSI) 
X 
X 
X 
X 
X 
Geriatric Depression Scale (GDS) 
X 
 
 
X 
X 
Confusion Assessment Method (CAM) 
X 
X 
X 
X 
X 
Standard Cognitive Assessment 
 
X 
 
 
 
Telephone Montreal Cognitive 
Assessment (t-MoCA) with DOW and 
MOY 
 
 
 
X 
X 
 
The delirium research assessments will not be provided to the treating clinicians.  Treating clinicians will assess 
and treat delirium as usual, including assessment and correction of reversible causes, behavioral management 
and use of IV haloperidol for agitation, if needed.  Rescue doses of haloperidol will be recorded in the study. 
Blood Acquisition 
Blood will be collected at four times points 1) Baseline: at the time of the pre-operative study assessments 
or on day of surgery; 2) on POD 1 while in the intensive care unit; 3) on POD 2 while in the intensive care 
unit; and 4) within 48 hours prior to discharge or days 8-10, at the latest. A total of 80 ccs of blood will be 
collected. Blood samples will be collected into sterile vacuum tubes using either a vacutainer or butterfly 
system, at the preference of the phlebotomist. All samples will be centrifuged.  The plasma and buffy coat 
will be separated from red blood cells, aliquoted into small samples, labelled and frozen at -80 Celsius for 
future use.  Blood samples will be stored in a biomarker bank for further analysis. 
Blood Storage 
Using all blood samples from our participants, we will create a bio-repository of genetic material and plasma, 
a resource for future biomarker discovery studies.  The banked specimens will be coded and stored in a -
80 Celsius freezer at a BIDMC facility.  A list linking study numbers to participants will be kept in a secure 
computer database.  In the future, the frozen plasma or DNA may be shared with other scientists studying 
a similar relationship between delirium and genetic factors after a formal application procedure and scientific 
review process approved by the IRB.  Information including contact information, rationale for studying data 
and intended use of data may need to be approved by CCI/IRB prior to sharing data.  All such studies will 
be carried out under controlled access and under the close supervision of the study team.  In these cases, 
the study investigators will maintain confidentiality of the specimens by maintaining the de-identification of 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
9 
 
 
 
patient information to the other scientists.  We plan to store these specimens indefinitely.  None of the 
results from these studies will be shared with participants or their family members and none of the genetic 
information obtained will be included in the patient’s medical records.  All patients approached for 
participation in study will also need to agree to participation in blood collection/storage as noted in informed 
consent. 
Follow Up 
A follow-up assessment will be administered at 1 month and 1 year post-discharge over the telephone and 
will include a telephone version of the MoCA known as the T-MoCA, DSI, GDS, and CAM.    
Study Outcomes 
Primary Outcome 
The primary objective of this study was the incidence of in-hospital delirium at any time during a patients’ 
hospital stay.    
Secondary Outcomes 
The secondary outcomes included duration of delirium, postoperative neurocognition at discharge, 48-
hour breakthrough analgesic requirements, and ICU and hospital lengths of stay. 
Data Collection 
The participant’s demographic data such as age, sex, ethnicity, race and body mass index will be recorded. 
Patient comorbid conditions, surgery and anesthetic drugs used will be obtained from Society of Thoracic 
Surgery database and Anesthesia Information Management System, which is a clinical outcomes registry that 
records and assesses the care of adult patients undergoing cardiac procedures at participating hospitals. 
Pertinent characteristics include: preoperative medications, comorbidities, surgical characteristics, and 
postoperative outcomes, including 30 day mortality and major adverse events like renal failure during hospital 
admission. Information on the sedatives and analgesics given within six hours prior to initiation of the cognitive 
assessment will be recorded, as to determine whether there is an effect on performance. The total opioid 
dosage administered during the first 48 hours post operatively, pain scores and patient delirium assessment 
data will be collected using REDCap. REDCap is a web-based application that allows customized data 
collection and entry. The study team will build and maintain the case report form electronically. Additionally, 
internal audits will be conducted to ensure data completion and data quality. Data will be kept secure in 
computers with password protection.  All data will be analyzed with modified intention to treat basis, in which 
all subjects who receive at least one dose of a study medication will be included.   
Data Security and Storage  
All data will be kept secure in the password-protected BIDMC network servers.  The paper format will be 
stored in locked file cabinets during the study period. Study data will be entered in datasheets and stored 
on a secure password-protected computer on the BIDMC network. Each patient will be assigned a study-
specific ID number.  The data will have all HIPAA identifiers removed and a random study number assigned 
to each patient.    
Safety Reporting  
Our patient population is by definition undergoing high risk surgery and is critically ill.  It is expected that 
they will have a number of unrelated adverse health events during the course of their hospital stay.  The 
potential adverse effects such as the number of episodes of hypotension (predefined as < 90mm systolic 
for 5 minutes or more), and bradycardia (predefined as <40 beats per minute), will be collected from the 
ICU charts.    


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
10 
 
 
 
Therefore, we will limit the scope of our AE monitoring and reporting to the following: 
o 
All Serious Adverse Events, including an unexpected death, believed to be related to the study   
o 
Unexpected, non-serious Adverse Events believed to be possibly or probably related to the 
intervention 
Evidence for adverse events will be assessed daily during the hospital stay, for a maximum of 10 days. 
Statistical Analysis  
Please refer to the Statistical Analysis Plan (SAP) for details of the power calculation and analyses.   
Benefits to the Subject 
There is a possible benefit to those enrolled in the dexmedetomidine and acetaminophen group, as their 
incidence of delirium can possibly be reduced, however we cannot guarantee this. Society as a whole will 
benefit in the future as a result of knowledge gained from the research.   
Risks to the Subject 
Risk of the Drugs Used 
The drugs dexmedetomidine and acetaminophen are FDA approved for sedation and analgesic purposes.  
Bradycardia and hypotension are less common side effects with dexmedetomidine and in an intensively 
monitored setting of cardiac surgical ICU, the risks of bradycardia and hypotension can be managed 
effectively.  Liver dysfunction is a rare side effect associated with IV acetaminophen.  However, the drug is 
commonly used already in the perioperative setting routinely as the benefits seem to outweigh the risks.  
No routine monitoring is done for liver dysfunction in the current standard of care. 
Risk Associated with Blood Draw 
There is a small risk of phlebotomy to obtain serum for the serum biomarker assays at four time points 
during the study.  Wherever possible, the serum collection will be obtained at the same time as phlebotomy 
and other labs for routine clinical laboratory work, thereby eliminating an additional risk imposed by a 
separate phlebotomy for study purposes.  However, in rare cases such as at the time of discharge, patients 
may require a separate lab draw. The risks of the phlebotomy procedure itself are minimal and are primarily 
related to pain or bruising at the needle puncture site.  Since the amount of blood required at each time 
point is small the risks from anemia or blood loss are negligible.  The blood draws will total only 80 cc’s 
over a maximum of four weeks, which is considered minimal risk.   
Risk of Breach of Confidentiality  
Patients will be referred to by a study number, and records will be password protected on BIDMC network 
servers. No identifiable data will be shared with the funding agency, or across institutions.  The information 
that we collect from this research project will be kept confidential.  All information will be stored in a HIPAA 
compliant database.   
Risk/Benefit Ratio 
The drugs used for this study are approved by the FDA for sedation and analgesic purposes.  When 
monitored in the intensive care setting, the risks of lower blood pressures or heart rates are far too small 
compared to the benefits of decreased delirium following cardiac surgery.   


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
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11 
 
 
 
Inducements  
No inducements will be offered. Neither patients nor healthcare providers will be paid as part of their 
participation in the study.      
Participant Withdrawals  
Throughout the study participants will be reminded that participation is entirely voluntary and that they have 
the option to withdraw at any time, for any reason. 
Subject Protection 
Patients will be contacted directly for this study. The informed consent will be explained and obtained in a 
secure and private location such as the preadmission testing clinic, cardiac catheterization holding areas, 
cardiac surgery clinic, and/or in the pre-operative holding area. Patients will be informed that their decision 
to participate or not to participate will in no way affect their relationship with their health care provider. 
Furthermore they will still receive all information about their analgesic management, as is the standard of 
care.  Patients will also have the ability to discontinue their participation at any time.   
  
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
12 
 
 
 
STATISTICAL ANALYSIS PLAN 
 
Introduction 
This Statistical Analysis Plan describes the analysis of the prospective randomized controlled trial that 
has been reviewed and approved by the Committee on Clinical Investigations at Beth Israel Deaconess 
Medical Center (2014P000413) and will be conducted in accordance with all applicable human subjects’ 
research requirements and applicable federal regulations.   
 
Study Aims 
Briefly, this randomized, factorial clinical trial evaluates the effect of intravenous acetaminophen versus 
placebo, combined with intravenous propofol versus dexmedetomidine, for postoperative sedation and 
analgesia respectively, in adult patients 60 years or older undergoing coronary artery bypass grafting 
(CABG) or combined CABG/valve surgeries to assess the incidence and duration of postoperative delirium.  
Study Design 
This is a single-center randomized controlled factorial trial of two sedative and two analgesic regimens. 
Study Population and Sites 
The study will prospectively enroll patients undergoing cardiac surgery at Beth Israel Deaconess Medical 
Center in Boston, Massachusetts.  This includes patients enrolled between September 2015 and April 2018.   
Randomization 
Randomization will be by pre-prepared using a computer generated block randomization in SAS 9.3. Details 
of the block size are kept confidential until the completion of study enrollment.  This schema will be created 
by the unblinded statistician (Ariel Mueller, MA) and sent to the research pharmacy.  Members of the 
research pharmacy will be responsible for preparing and dispensing the study medications following an 
active order for study medications.  Specifically this includes preparation and blinding of the placebo in 
accordance with the study randomization schema.   
Patients will be randomized to one of four groups in a 1:1:1:1 fashion. This includes:  
• 
Acetaminophen and Dexmedetomidine 
• 
Acetaminophen and Propofol 
• 
Placebo and Dexmedetomidine  
• 
Placebo and Propofol 
Primary Endpoints 
The primary endpoint will be the incidence of in-hospital delirium.  This is assessed via the Confusion 
Assessment Method (or CAM-ICU for intubated patients) daily postoperatively, as specified in the study 
protocol.  If a patient is noted to be positive for delirium on any postoperative day, they will have been 
documented as achieving the primary study endpoint.  
Our pre-specified primary analysis will assess the incidence of delirium between patients receiving IV 
acetaminophen versus placebo. 
Secondary Endpoints 
Secondary outcomes for this study include: 
• 
Duration of delirium 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
13 
 
 
 
o 
Definition: The number of days of being positive for delirium on the CAM or CAM-ICU 
instruments will be recorded and assessed. This will be assessed as a continuous variable.        
• 
Postoperative cognitive decline at discharge, one month and one year postoperatively  
o 
Definition: This will be assessed by using the change in Montreal Cognitive Assessment 
score at this time point since baseline.  This will be assessed as a continuous variable.      
• 
Breakthrough analgesic requirements within the first 48 hours postoperatively 
o 
Definition: This will be assessed by calculating the total morphine equivalent administered 
in the first 48 hours postoperatively, with time zero starting at ICU admission.  This will be 
assessed as a continuous variable.      
• 
Intensive care unit (ICU) length of stay  
o 
Definition:  This will be defined as the number of hours admitted in the ICU prior to 
transfer to the general floor.  This will be assessed as a continuous variable and reported 
in hours.   
• 
Hospital length of stay 
o 
Definition: This will be calculated as the day of hospital discharge minus the day of 
surgery plus one.  This will be assessed as a continuous variable and reported in days.    
• 
Predefined potential adverse effects of the study drugs including:  
o 
Number and duration of episodes of hypotension  
▪ 
Definition: This is predefined as less than 90 mm Hg systolic blood pressure for 
five minutes or more 
o 
Number and duration of episodes of bradycardia  
▪ 
Definition: This is predefined as less than 40 beats per minute. 
• 
The proportion of patients who complete the protocol successfully will be measured.  
• 
If this sedation and analgesic regimen is abandoned by the clinicians, the reason will be 
qualitatively described at the end of the study. 
• 
Levels of inflammatory biomarkers 
Covariates 
Trial data will be collected managed using REDCap electronic data capture tools hosted at Beth Israel 
Deaconess Medical Center. REDCap (Research Electronic Data Capture) is a secure, web-based 
application designed to support data capture for research studies, providing 1) an intuitive interface for 
validated data entry; 2) audit trails for tracking data manipulation and export procedures; 3) automated 
export procedures for seamless data downloads to common statistical packages; and 4) procedures for 
importing data from external sources. The REDCap system includes validation rules for data entry to help 
ensure data accuracy, and has a full audit trail of data entry and changes. 
Data collection includes the participant’s demographic data such as age, sex, ethnicity, race and body mass 
index will be recorded. Patient comorbid conditions, surgery and anesthetic drugs used will be obtained 
from Society of Thoracic Surgery database and Anesthesia Information Management System, which is a 
clinical outcomes registry that records and assesses the care of adult patients undergoing cardiac 
procedures at participating hospitals. Pertinent characteristics include preoperative medications, 
comorbidities, surgical characteristics, and postoperative outcomes, including 30 day mortality and major 
adverse events like renal failure during hospital admission. Information on the sedatives and analgesics 
given within six hours prior to initiation of the cognitive assessment will be recorded, as to determine 
whether there is an effect on performance. The total opioid dosage administered during the first 48 hours 
post operatively, pain scores and patient delirium assessment data will be collected using REDCap. 
The overall flow and reporting of study recruitment, enrollment and follow up will follow the CONSORT 
recommendations for the reporting of randomized controlled trials.   


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
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Sample Size Estimation 
This is a prospective, randomized, placebo controlled, double-blinded, factorial design study consisting of 120 
patients to assess the incidence and duration of postoperative delirium following cardiac surgery.  From the 
previous delirium studies conducted at our institution, the baseline delirium incidence was 50%.  The pilot 
study showed a 66% reduction in the incidence of delirium.  For the power calculation, a 50% reduction in the 
delirium incidence was used.  Each group needed 56 patients (alpha=0.05 and 1-Beta=0.80). This study will 
not be powered for secondary outcomes.   
Because complete data from 112 patients is required in order for analysis, we plan to enroll enough patients 
to obtain data from 120 patients who received the study intervention (60 patients per group - acetaminophen 
vs. no acetaminophen).  We estimate that approximately 150 patients will be enrolled (consented) in order 
to achieve this sample size.  This increase is required because it is possible that patients can be withdrawn 
both before randomization (i.e. cancelled surgery) as well as after randomization but before receiving the 
study intervention (i.e. change in surgery type intraoperatively).  Enrollment will be stopped once a total of 
120 randomized patients have undergone surgery and received the study medications. 
General Approach to Statistical Analyses 
Baseline and demographic characteristics will be summarized and presented using descriptive statistics.  
Continuous data will be presented as means ± standard deviations or medians (interquartile range) 
depending on the distribution of the data.  The Shapiro-Wilk test will be utilized in order to determine whether 
or not the data follows a Gaussian distribution.  Differences in continuous data between study groups will 
be assessed using a parametric t-tests or Wilcoxon Rank-Sum tests as appropriate.  Categorical data will 
be presented as frequencies and proportions and assessed with a chi-square test.  In the event that cell 
counts are small (less than 5), we will employ the use of a Fisher’s Exact test.  For all analyses two-sided 
p-values less than 0.05 will be considered statistically significant.  SAS 9.3 (SAS Institute Inc., Cary, NC) 
or later will be utilized for all analyses.   
Analyses will be performed on a modified intention to treat basis, in which all patient who receive at least 
one dose of any of the four study medications will be included. 
 
Analysis of the Primary and Secondary Outcomes 
The DEXACET trial has been designed as a factorial, randomized controlled trial with four treatment groups.  
We will therefore aim to test 1) the effect of acetaminophen versus placebo and 2) the effect of 
dexmedetomidine in comparison to propofol in the event that there is no interaction between treatment 
effects.  However, the first of these (the effect of acetaminophen) is considered the most interesting and 
the study has been powered to answer this question using an unadjusted chi-squared test.   
To test whether or not there is an interaction we will compose a logistic regression model include indicator 
variables for the acetaminophen group as well as the dexmedetomidine group.  We will further include an 
interaction term in this model composed of the indicator variables multiplied together.  If there is a significant 
interaction between groups when assessing the incidence of in-hospital delirium, we will interpret the results 
stratified by all four groups, presenting the main effects only after taking into account the other factor, in a 
‘inside the table analysis’.  If the interaction term is not significant we will present the main effects by pooling 
data across the other factor.   
Kaplan Meier curves and a Cox proportional hazards model was used to compare time to experiencing 
delirium, after confirming the proportional hazards assumption is met.  To test whether the Proportional 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
15 
 
 
 
Hazards (PH) assumption holds, we will include a time varying covariate with group in the model.  Given 
the factorial design this approach will be replicated in models for all four factorial groups, as well as the 
pairwise comparisons (dexmedetomidine vs propofol; acetaminophen vs placebo) to ensure this 
assumption remains valid.  In the event that this assumption is not valid, we will include a time-varying 
covariate in the model.  Hazards ratios and their associated 95% confidence intervals will be reported.   
Repeated measures analyses including generalized estimating equations with robust variance will be 
employed to assess for differences in continuous variables that are measured at multiple time points over 
time between groups using mixed model regression.  
Interrater reliability assessments of delirium will be assessed for approximately 10% of patients.  This 
includes assessment of both for the presence of delirium, and for key features including acute change, 
inattention, disorganized thinking and an altered level of consciousness. Percent agreement, kappa and 
weighted kappa will be reported.   
Given the nature of a randomized controlled trial, we do not anticipate seeing differences between groups 
in baseline characteristics; however, we will perform a secondary analysis, adjusting for any differences 
observed between groups and presenting adjusted odds ratios and their associated 95% confidence 
intervals.  
Interim Analyses 
There will be no interim analysis. 
Missing Data 
The frequency and percentage of missing values for each variable will be collected, analyzed and reported 
as necessary. If there are missing values for the outcome variable(s), individual patients will be excluded.  
Highly incomplete covariates (>33% of observations missing) will be excluded from analyses.  In the event 
that a variable is missing more than 10% of the time we will consider imputation.  If missing values are 
missing at random (MAR) or not at random (MNAR), multiple imputation will be performed. Missing values, 
selection or exclusion of observations and variables and handling of missing values in the statistical analysis 
will be describes carefully and sensitivity analysis will be provided in the manuscript.   
Statistical Analytical Issues 
 
Adjustments for Covariates 
Given the randomized nature of this study, there will be no covariate adjustment in the primary analysis. If 
differences between groups persist after randomization we will perform a post hoc analysis including 
variables that are significantly differ between groups.   
Multiple Comparisons 
There will be no adjustment for multiple testing. Results of secondary outcomes and post hoc analyses will 
therefore be considered exploratory.   
Examination of Subgroups 
Our pre-specified primary analysis will assess the incidence of delirium between patients receiving 
intravenous acetaminophen versus placebo. Predefined subgroup analyses will be performed for our 
primary and secondary outcomes for the following groups: 
• 
Two sedative groups: dexmedetomidine versus propofol 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
16 
 
 
 
• 
All four factorial groups including both sedatives (dexmedetomidine and propofol) and analgesics 
(acetaminophen and placebo).    
Post-hoc Analyses 
Post-hoc data driven analyses are allowed after the following are undertaken: 
(a) Document which analyses were conducted after the results for the Primary and Secondary Aims 
are analyzed. 
(b) Document the rationale for these analyses.  
(c) Pre-specify their interpretation in the context of the primary and secondary results and their 
impact on the overall trial conclusions. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
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18 
 
 
 
eAPPENDIX 2. FAST TRACK PROTOCOL AND INTRAVENOUS DRUG ADMINISTRATION 
GUIDELINES    
 
FAST TRACK PROTOCOL FOR CARDIAC SURGERY  
Version: 
12/2015 
Institutional Authors: 
BIDMC Perioperative Cardiovascular Intensive Care Unit 
Committee  
 
Cardiac Surgery Fast Track Ventilator Weaning Guideline 
Purpose:  Patients who have undergone an uncomplicated cardiac surgical procedure should be able to 
wean quickly from the ventilator, fostering a more rapid recovery. The fast track weaning guideline provides 
a decision-making framework that will expedite the process of weaning most efficiently  
Patient Selection: Selection of patients for fast track ventilator weaning will be made at time of handoff in 
Cardiovascular Intensive Care Unit (CVICU).  It is a collaborative decision by the healthcare team at which 
time an order is placed in the system.  
Ventilator Settings on Arrival 
All patients are placed on: assist control positive end expiratory pressure (PEEP) 5, fraction of inspired 
oxygen (FiO2) 100%, tidal volume (vT) 6-10 ml/kg (ideal body weight) and respiratory rate 12-14 (or per 
anesthesia) 
Extubation Goal (4 hours for Fast Track) 
• 
Nurse will write time of arrival on White Board 
o 
This allows all members of the team to know when 23 hours is up to prevent Society of 
Thoracic Surgeons (STS) designation of prolonged ventilation 
 
PRE-EXTUBATION 
I. 
Hand Off  
• 
Patient designated as appropriate for fast track wean 
o 
CVICU Nurse  
o 
Anesthesia 
o 
Intensive Care Unit (ICU) Provider 
o 
CVICU Respiratory Therapist (RT) 
 
II. 
Difficult Airway 
• 
ICU Provider, Intensivist, Registered Nurse (RN), and RT discuss plan in detail 
o 
Who needs to be notified when patient ready to extubated? 
o 
Does ICU Provider or Intensivist want to be present for extubation? 
o 
What additional equipment is needed at the bedside? 
 
III. 
Rewarming Guidelines 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
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• 
All Patients on arrival 
o 
Change intravenous fluid (IVF) to warmed IVF 
o 
Warmed blankets 
o 
Hourly temperature for the first 4 hours postoperatively  
o 
Record temperature prior to administration of reversal agents 
• 
If Temperature ≤ 36°C (96.8°F) 
o 
Bair Hugger set at 42°C 
o 
May remove when temp > 36°C  (96.8°F) for at least one hour 
o 
Suggest defer bath until > 36°C for at least one hour 
• 
Nasal Thermometer Probes 
o 
May be used if still in place from Operating Room (OR) 
o 
Should be removed when reversal agents are administered or at 8 hours, whichever 
comes first 
o 
If accuracy is being questioned, switch to oral temperatures 
 
IV. 
Weaning Criteria 
 
Patient Criteria for Ventilator Weaning 
Parameter 
Criteria 
Richmond 
Agitation-Sedation 
Scale (RASS) 
+1 thru -1 
Cardiac Index 
≥ 2.0 L/min/m2 
Mean Arterial Pressure (MAP) 
> 60mm Hg < 80mm Hg 
Cardiac Rhythm 
Stable 
Inotropic Support 
No more than one inotropic drip 
Chest Tube Drainage 
< 100 ml/hour 
Core Temperature 
≥ 35 o C 
pH 
≥ 7.32 
 
V. 
Page ICU Provider at time patient placed on Continuous Positive Airway Pressure (CPAP) 5/5 
• 
Notify provider if cuff leak present or not 
 
VI. 
Arterial Blood Gas (ABG) should be obtained 30 minutes after placed on CPAP 
• 
Patient condition may warrant earlier sampling to expedite extubation 
o 
Should discuss with team 
 
 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
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EXTUBATION 
VII. 
Extubation Criteria 
 
Patient Criteria for Extubation 
Parameter 
Criteria 
Strength 
Able to lift and hold head for ≥ 5 sec 
RASS 
+1 to -1 
Heart Rate  
60-100  
Cardiac Index 
≥ 2.0 L/min/m2 
MAP 
> 60mm Hg < 90mm Hg  
Cardiac Rhythm 
Stable 
Inotropic Support 
No increase  
Chest Tube Drainage 
< 100 ml/hour and not increasing 
Core Temperature 
≥ 36o C (96.8°F) 
Respiratory Rate  
10-24 bpm 
ABG on following settings:  
CPAP FiO2  ≤ 50% PEEP 5 PS 5 
pH 7.34-7.45; pCO2 35-45; PaO2 ≥ 80 
 
VIII. 
If not within fast track criteria then page the ICU provider immediately to discuss plan of action and 
if not ready for extubation return to step IV. 
 
IX. 
Meets Extubation Criteria 
• 
Decision to proceed with extubation may be made by the CVICU RN, in coordination 
with the CVICU RT  
• 
For patients with a difficult airway, the plan to extubate should be discussed with the 
intensivist and ICU provider, prior to extubation 
 
X. 
Extubate 
• 
Head of Bed (HOB) should be elevated at least 60° unless contraindicated 
• 
Endotracheal Tube (ETT) should be suctioned prior to extubation, with 
hyperoxygenation of the patient before and after suctioning (use the Suction 100% 
function on ventilator).           
• 
Suction mouth with Yankauer immediately prior to extubation.  
• 
Nasogastric tube, if present, should be aspirated and discontinued.  
• 
Explain procedure to patient, informing them that a strong cough will be necessary as 
the ETT is withdrawn; explain that patient may be unable to speak for a time.  
• 
Patient to be placed on face tent/nasal cannula to provide adequate SpO2 ≥ 92% 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
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POST-EXTUBATION CARE 
Over the next several hours, oxygen should be weaned to maintain peripheral capillary oxygen saturation 
(SpO2) ≥ 92%.          
           Nasal Cannula O2 Flow / FiO2 
Oxygen Flow L/min 
Approximate FiO2 
Room Air 
21% 
1 L/min 
24% 
2 L/min 
28% 
3 L/min 
32% 
4 L/min 
36% 
5 L/min 
40% 
6 L/min 
44% 
  
• 
ABG 30 minutes after extubation only if clinical suspicion of poor respiratory function  
• 
Continuous SpO2 Monitoring 
• 
Observation and assessment of patient for respiratory distress or increased work of breathing 
• 
Incentive Spirometry (IS) every 30 min x 4, every 1 hour x 4; then hourly while awake or more often, 
as indicated 
• 
Dangling on edge of bed within 2 hours should be performed unless contraindicated 
• 
Patient/Family instruction in use of splint pillow during coughing and deep breathing  
• 
Patient instruction in pain control as an important part of improved ventilation 
• 
Position with HOB > 45, or up in chair, for enhanced respiratory pattern/coughing  
• 
Weaning of FiO2 as tolerated to SpO2 >92% 
 
 
 
 
 
 
 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
22 
 
 
 
 
INSTITUTIONAL INTRAVENOUS DRUG ADMINISTRATION GUIDELINES 
 
Version Date: 
01/2002 
Revision Date: 
11/2014 
Medication: 
Dexmedetomidine Hydrochloride (PRECEDEX) 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
23 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


Effect of Postoperative Intravenous Acetaminophen versus Placebo, Combined with Propofol or 
Dexmedetomidine, on Postoperative In-Hospital Delirium Among Older Patients Following Cardiac 
Surgery: The DEXACET Randomized Clinical Trial 
24 
 
 
 
REFERENCES 
 
1. Rudolph JL, Jones RN, Levkoff SE, et al. Derivation and validation of a preoperative prediction rule 
for delirium after cardiac surgery. Circulation. 2009;119(2):229-236. 
2. Inouye SK. Delirium in older persons. N Engl J Med. 2006;354(11):1157-1165. 
3. Saczynski JS, Marcantonio ER, Quach L, et al. Cognitive trajectories after postoperative delirium. N 
Engl J Med. 2012;367(1):30-39. 
4. Lin YY, He B, Chen J, Wang ZN. Can dexmedetomidine be a safe and efficacious sedative agent in 
post-cardiac surgery patients? a meta-analysis. Crit Care. 2012;16(5):R169. 
5. Dasta JF, Jacobi J, Sesti AM, McLaughlin TP. Addition of dexmedetomidine to standard sedation 
regimens after cardiac surgery: an outcomes analysis. Pharmacotherapy. 2006;26(6):798-805. 
6. Shehabi Y, Grant P, Wolfenden H, et al. Prevalence of delirium with dexmedetomidine compared with 
morphine based therapy after cardiac surgery: a randomized controlled trial (DEXmedetomidine 
COmpared to Morphine-DEXCOM Study). Anesthesiology. 2009;111(5):1075-1084. 
7. Maldonado JR, Wysong A, van der Starre PJ, Block T, Miller C, Reitz BA. Dexmedetomidine and the 
reduction of postoperative delirium after cardiac surgery. Psychosomatics. 2009;50(3):206-217. 
8. Corbett SM, Rebuck JA, Greene CM, et al. Dexmedetomidine does not improve patient satisfaction 
when compared with propofol during mechanical ventilation. Crit Care Med. 2005;33(5):940-945. 
9. Holmer Pettersson P, Jakobsson J, Owall A. Plasma concentrations following repeated rectal or 
intravenous administration of paracetamol after heart surgery. Acta Anaesthesiol Scand. 
2006;50(6):673-677.