Clinical trial NCT04021264: The Impact of an Epidural Anesthetic on the Consumption of Sevoflurane in Major Abdominal Surgery
Official title: The Impact of an Epidural Anesthetic on the Consumption of Sevoflurane in Major Abdominal Surgery
Study type: INTERVENTIONAL
Overall status: WITHDRAWN
Phase: PHASE2
PHASE3
Conditions: Bowel Disease
Liver Diseases
Pancreas Disease
Anesthesia; Functional
Keywords: Major abdominal surgery
epidural
environmental footprint
Lead sponsor: University of Alberta
Sponsor class: OTHER
First posted: 2019-07-16
Enrollment: 0
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Double-blinded, randomized controlled, prospective
Primary purpose: TREATMENT

Brief summary: Major abdominal surgery - like non-laparoscopic bowel resection, liver, gastric, or pancreas surgery - is performed under general anesthesia. Pain control for after the surgery can be achieved purely with intravenous and oral pain medication or in combination with freezing of the nerves. Nerve freezing (nerve block) placed before surgery has the potential to substantially reduce the amount of inhaled anesthetic given to the patient during surgery. This can benefit the patient with being more awake and crisp more quickly after surgery. It can also reduce cost to the system. A further benefit which has received very little attention so far, is that reducing the amount of inhaled anesthetic given also lowers the environmental footprint created by the anesthetic.

The investigators of the proposed study plan to quantify the amount of inhaled anesthetic used for each case and will compare how the consumption is affected by whether the epidural block is applied before or after surgery. Patients will have a nerve block catheter (epidural catheter) placed prior to the induction of general anesthetic by an experienced regional anesthesiologist. The epidural catheter will be bolused with a solution to which the anesthesiologist is blinded which will either be local anesthetic or dextrose (sham). The general anesthetic will be conducted according to a the protocol with the aim of maintaining a standard anesthetic depth monitored by patient state index (PSI). Measurements of the MAC-Value (minimum alveolar concentration) of inhaled anesthetic will be recorded every five minutes and will be noted down by a blinded observer. At the end of the case the anesthesiologist blinded to the solution will inject another solution (now a dextrose (sham) or local anesthetic before the patient is woken up.

Detailed description: Following ethics approval, eligible patients meeting the inclusion/exclusion criteria will be consented in pre-assessment unit or day surgery ward at least 2 hours prior to their surgery. Patients will then be randomized into two groups:

Epidural catheter insertion with 14 mL of a solution containing 0.125% bupivacaine and 2 mcg/ml sufentanil injection (Treatment group) Epidural catheter insertion with 14 mL normal saline injection (Sham group) The patient, anesthesia provider, data recorder, OR staff and Post Anaesthetic Care Unit (PACU) nurses, will be blinded at the beginning of the case. After randomization, each patient will receive a clear 20 mL syringe containing either the Treatment or the Sham solution. Prior to induction of general anesthesia, an epidural catheter will be inserted by an experienced acute pain physician who has been performing epidural blocks for at least 5 years. Catheter placement will be verified by a single test dose of 60 mg lidocaine to exclude subarachnoid tip location.

Induction of general anesthesia will follow a standardized protocol with the intravenous administration of fentanyl (2 mcg/kg), propofol (2 mg/kg), and rocuronium (0.6 mg/kg). General anesthesia will initially be maintained with sevoflurane at 1.0 age-adjusted Minimal Alveolar Concentration (MAC). Subsequently, the age-adjusted MAC will be titrated to achieve an intraoperative PSI target of 25-50 (Sedline, Masimo®), and intraoperative heart rate (HR) and mean blood pressure (MBP) target of +/-30% baseline values. The anaesthesiologist will have the ability to administer IV boluses of analgesic (remifentanil 0.5mcg/kg) at if the PSI is \<50 and the MBP or HR is above 30% of baseline. Vasopressors such as phenylephrine (100 mcg IV bolus) and ephedrine (5 mg IV bolus) can be used as last-line therapy to treat hypotension that is unresponsive to MAC adjustments. The age-adjusted MAC value will be recorded every 5 minutes starting at the time of skin incision until the time of skin closure. In addition, intraoperative analgesic and vasopressor usage are recorded. The epidural catheter will be run continuously throughout the surgery with 4-6 ml/h with study drug number 1 as per randomization - so either treatment or sham. After the conclusion of MAC recording and prior to emergence from general anesthesia, the anaesthesiologist will be unblinded to the randomized groups, and the patients who received Sham solution will be given 20 mL of the treatment solution via the interscalene catheter to ensure patients receive adequate analgesia postoperatively.

Postoperatively, patients will be transported to PACU where the distribution of the sensory or motor block will then be checked and recorded 30 minutes after arriving in PACU in both groups. The NRS for pain will also be recorded in PACU at 0, 15, 30 and 45 minutes.

Eligibility criteria: Inclusion Criteria:

* Patients undergoing elective reconstructive foot and ankle surgery
* Patients eligible for popliteal and saphenous nerve block
* All adults 18 years of age or older
* Capable to give consent

Exclusion Criteria:

* Patients who are unable to give consent
* Local anaesthetic allergy
* Hemidiaphragm paresis on the contralateral side to the block/surgery site
* Bleeding diathesis
* Coagulopathy
* Pre-existing neurological deficits
* Patients with a Body Mass Index \>35
* Patients with significant comorbidities, physiological limitations, and allergies that are unable to tolerate the protocolized induction and maintenance of anesthesia.

Primary outcomes:
measure: Average age-adjusted MAC of sevoflurane
timeFrame: Intraoperative measurement done at the end of anesthetic
Secondary outcomes:
measure: Intraoperative heart rate
timeFrame: Intraoperative measurement
measure: Intraoperative opioid use
timeFrame: Intraoperative measurement
measure: Postoperative opioid use in PACU
timeFrame: Up to 24 postoperative hours
measure: Maximum pain scores in the first 24 post-operative hours
timeFrame: Up to 24 postoperative hours
measure: Nausea and vomiting in the first 24 post-operative hours
timeFrame: Up to 24 postoperative hours
measure: 24 hour opioid consumption
timeFrame: Up to 24 postoperative hours
measure: The sedation score in PACU
timeFrame: 1st postoperative hour
measure: Temperature testing ("Cold test")
timeFrame: 1st postoperative hour
measure: Intraoperative vasopressor usage
timeFrame: Intraoperative period
measure: Intraoperative mean blood pressure
timeFrame: Intraoperative period
Other outcomes:
Locations:
city: Edmonton
country: Canada
facility: University of Alberta Hospital
state: Alberta
Study officials:
affiliation: University of Alberta
name: Vivian HY Ip, MD
role: STUDY_DIRECTOR
affiliation: University of Alberta
name: Lora Pencheva, MD
role: STUDY_DIRECTOR
affiliation: University of Alberta
name: Rakesh V Sondekoppam, MD
role: STUDY_CHAIR
affiliation: University of Alberta
name: Timur JP Özelsel, MD, DESA
role: PRINCIPAL_INVESTIGATOR
References: