Vital Capacity in Ultrasound Guided Serratus Plane Block in Emergency Department Patients With Multiple Rib Fractures: A Randomized Controlled Trial
Phase: PHASE4
Conditions: Pain
Sponsor: Antonios Likourezos

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TITLE: Vital Capacity in Ultrasound Guided Serratus Anterior Plane Block in Emergency 
Department Patients with Multiple Rib Fractures: A randomized controlled trial 
 
 
 
 
Identifiers: NCT04530149   Unique Protocol ID: 2019-03-17 
 
 
 
Document Date:  March 4, 2021 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Vital Capacity in Ultrasound Guided Serratus Anterior Plane Block in Emergency 
Department Patients with Multiple Rib Fractures: A randomized controlled trial 
 
 
 
BACKGROUND  
Patients with multiple rib fractures are challenging from both pulmonary and analgesia 
perspectives. Adequate pain management is essential in prevention of complications secondary 
to decreased inspiratory volume. Significant morbidity and mortality of rib fractures is secondary 
to severe pain that limits ribcage movement, decreases inspiratory volumes and causes 
inadequate cough.  Decreased vital capacity predisposes patients to atelectasis, abnormal mucous 
clearance and pneumonia. The objective of this study is to assess the efficacy of the serratus 
anterior plane block (SAPB) in improvement of vital capacity in patients with multiple unilateral 
rib fractures when compared to conventional management with medications. Currently, evidence 
of efficacy of SAPB in managing pain secondary to multiple rib fractures is limited to case 
reports and series, none of which evaluate vital capacity. 
 
SIGNIFICANCE 
The findings of this study may indicate that SAPB is superior to pharmacological management in 
increasing vital capacity in patients with multiple unilateral rib fractures and suggest SAPB for 
first line therapy in patients with rib fractures. The findings may decrease the risk of pulmonary 
complications as well as the use of opiates in management of multiple rib fractures in the 
Emergency Department especially in patients with numerous comorbidities and contraindications 
to conventional treatment modalities. This study may support the need for training emergency 
medicine physicians in bedside SAPB in order to provide the optimal therapy for patient with 
multiple unilateral rib fractures. 
 
STUDY OBJECTIVES 
 
Our primary objectives are to evaluate whether ultrasound guided SAPB results in a greater 
improvement in percent predicted vital capacity compared to standard therapy with a sham 
injection.  We will also evaluate pain scores and the safety profile of the SAPB procedure 
compared to those receiving standard analgesia. 
 
HYPOTHESIS  
 
Our primary hypothesis is that SAPB is superior to sham injection in improving the percent of 
predicted vital capacity.  Our secondary hypothesis is that SAPB will have greater improvement 
in pain scores and have a superior safety profile compared to sham injection. 
 
STUDY DESIGN 
 

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This is a single center prospective, randomized, blinded clinical trial with a convenience sample 
that will be conducted in the Emergency Department of an urban level I trauma center.  
 
1. Identify and enroll all patients coming in to the ED patient with presumed or 
clinically apparent 2 or more unilateral rib fractures between T3 to T9, with a 
resting pain score of ≥5. All patients meeting exclusion criteria will be excluded.  
2. Randomization procedure: 
1. Pharmacy will dispense 30mL of injectate which will be randomized in 
block of 10 to either the SAPB group (30mL of 0.25% bupivacaine with 
epinephrine) or sham group (30mL of normal saline). 
3. Injection 
1. Patient consent will be obtained and time out will be performed on all 
patients. 
2. Patients will be placed on cardiac monitor and placed in lateral decubitus 
or if unable to turn, they will be supine. 
3. Under the usual sterile technique, the serratus anterior muscle overlying 
the 5th rib at the mid-axillary line will be identified with ultrasound. 
4. A spinal needle will be introduced in-plane under ultrasound guidance and 
advanced until the needle tip is located in the fascial plane just above the 
serratus anterior muscle. The needle tip will not be advanced unless 
completely visualized under ultrasound.  
5. Normal saline will be injected first to determine correct location of the 
needle tip. Spreading of fluid along the fascial plane will confirm the 
correct location of the needle tip. 
6. The normal saline will then be switched to the study drug of which 30mL 
of either normal saline or 0.25% bupivacaine with epinephrine which will 
then be injected into the fascial plane as described in Blanco et al, and 
Hetta et al. 
7. The study drug will be injected 5mL at a time and the patient will be asked 
if any symptoms of Local Anesthetic Systemic Toxicity (LAST toxicity) 
are present (perioral numbness, tinnitus, dizziness). 
8. After injection is completed the needle will be withdrawn and patient will 
remain on the cardiac monitor for another 30 minutes to monitor for 
symptoms of LAST toxicity (Di Gregorio). 
9. This procedure was based on the serratus anterior plane block protocol 
from Khalil et al. 
4. Slow Vital Capacity (SVC) Measurement 
1. SVC will be performed using spirometer that has been internally validated 
2. SVC will be performed by physicians trained by the respiratory therapy 
department and who have demonstrated validation compared to respiratory 
therapist obtained SVC values 
3. The patient will be sitting up when performing SVC and a script will be 
followed as to how to educate and coach the patient on performing 
appropriate incentive spirometry technique. 
4. At least 3 SVC measurements within 150mL of eachother are required to 
qualify for an accurate measurement. 

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5. The maximum of these 3 SVC values and a corresponding % predicted 
SVC will be obtained and considered the maximum % predicted SVC. 
6. % Predicted SVC will be obtained based on the National Health and 
Nutrition Examination Survey (NHANES III) calculator through the CDC. 
5. Pain scores  
1. Subjects will be asked to rate their maximum pain score from 0-10 with 
resting breathing and with deep breaths. 
 
Subjects:  
 
Subjects include English speaking patients 18 years of age or older with presumed or clinically 
apparent two or more rib fractures from T3-T9 and a pain score of 5/10 or above will be 
consented and randomized into one of two study arms: Nerve block vs. Sham injection. Patients 
must be able to demonstrate understanding of the informed consent, and also be able to verbalize 
how much pain they are having on a 10 point Numeric Rating Pain Scale. 
 
 
Eligibility Criteria:  
 
1. Inclusion Criteria: 
1. 18 years or older 
2. 2 or more acute unilateral rib fractures on radiographic imaging 
3. Pain Score ≥5 
2. Exclusion Criteria: 
1. GCS<13 
2. Penetrating trauma 
3. Pregnant 
4. Unable to give consent due to dementia or altered mental status 
5. Unable to perform spirometry 
6. Requiring immediate surgical intervention 
7. Known allergy to amide-type local anesthetics  
8. Known allergy to acetaminophen 
9. Known allergy to morphine sulfate 
10. Signs of infection or laceration at injection site 
11. Systolic BP <100 mmHg 
12. History of chronic pain, chronic use of analgesics 
13. History of substance abuse 
14. Painful distracting injury (injury causing significant pain that 
distracts the patient from having reliable scoring of rib fracture 
pain, i.e. femur fracture, dislocated joint) 
15. If patient received any other pain medication besides ketamine 
prior to the block 
 
 
Design:  

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1. Potential study patients will be identified through review of the emergency 
department (ED) electronic board, and ED physicians will also screen for 
potential study patients. Pain scores are assessed in triage as is standard in the ED.  
2. If the patient has pain from presumed or clinically apparent 2 or more unilateral 
rib fractures between T3 to T9, and he/she has a resting pain score of ≥5 on the 
Numeric Pain Rating Scale, where 0 is no pain, 5 is moderate pain, and 10 is the 
worst possible pain upon initial assessment, then he/she will be eligible to 
participate in the study.  
The patient will then be asked to participate if he/she does not have any exclusion 
criteria. 
3. At time of enrollment, the patient will have recorded pain scores, vital signs, and 
slow vital capacity measured. 
4. All patients will then receive as their initial analgesic oral acetaminophen 975 mg 
followed by morphine sulfate 0.05 mg/kg IV rounded to the nearest milligram.  
5. Each patient will then be randomized in either of two arms:  
1. Ultrasound guided serratus anterior plane block (SAPB) with 30mL 0.25% 
bupivacaine with epinephrine. 
2. Ultrasound guided serratus anterior plane injection with placebo injection 
with 30mL of normal saline. 
6. Investigators will be blinded to the arm that the patient has been randomized to, as 
the randomization will occur through the pharmacy dispensing the medication. 
7. Using an online randomizer in blocks of 10, the pharmacy will dispense either 
30mL of normal saline for the sham group, or 30mL of 0.25% bupivacaine with 
epinephrine for the nerve block group. 
8. All patients will receive either SAPB or placebo injection within an hour of 
receiving the initial analgesics of acetaminophen and morphine. 
9. If the patient still has a pain score ≥5 thirty minutes after the injection, the treating 
physician will be informed and the patient will be medicated at the treating 
physician’s discretion. 
10. The patient will be followed up with up to 24 hours throughout their hospital stay. 
 
Data Collection Procedures:  
1. Demographics 
1. Age, sex, ethnicity, height 
2. Past medical history 
1. Smoking status (current, prior, never smoker), diabetes, cirrhosis, chronic 
obstructive pulmonary disease (COPD), asthma, if patient uses home 
oxygen 
3. Injury Mechanism 
1. Occupant in motor vehicle collision, fall from an elevation, fall down 
stairs, fall from standing, pedestrian or bicyclist struck by moving vehicle, 
bike collision or fall from bike while riding, driver or passenger in 
motorcycle/ATV/motorized scooter collision, assault, unknown 
mechanism, or other 
2. Date and time of injury 

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3. GCS score 
4. Injury Severity Scale 
4. Imaging 
1. Side of rib fractures 
2. Number of rib fractures on x-ray and on CT chest 
3. Rib fracture location: anterior, lateral, posterior, T1-12 
4. Type of imaging showing rib fractures 
5. Presence of following: atelectasis, hemothorax, infiltrate (right/left), 
interstitial edema, pneumothorax, pulmonary contusion 
5. Medication 
1. Any medications type and dose given prior to randomization  
6. At Time 0 (time of enrollment): 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 
2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 
5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
7. At Time 30 minutes post injection 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 
2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 
5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
8. At Time 60 minutes post injection 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 

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2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 
5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
9. At Time 3-6 hours post injection 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 
2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 
5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
10. At Time 12 hours post injection 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 
2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 
5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
11. On 24 hours post injection 
1. Vital signs 
2. Resting pain score from 0-10 
3. Deep breath pain score from 0-10 
4. Slow Vital Capacity (SVC) 
1. Measured until 3 measurements are within 150mL of eachother 
2. % predicted SVC is measured based on NHANES III Calculator 
using age, sex, ethnicity and height. If ethnicity not included in 
calculator will select Caucasian.  
3. Maximum SVC and maximum % predicted SVC 

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5. Symptoms after injection: sedation, dizziness, dysarthria, nausea, new 
cardiac rhythm (significant tachycardia or bradycardia, SVT, etc), new 
significantly increased shortness of breath, perioral numbness, pruritis, 
seizure, syncope, tinnitus, vomiting 
12. Slow vital capacity 
1. Researchers will be trained on appropriate incentive spirometry technique 
by the respiratory therapy team and their accuracy will be confirmed 
2. Patients will then be instructed to perform SVC, we will get 3 SVC 
measurements within 150mL of eachother and then record the maximum 
SVC.  
3. Percent predicted vital capacity will be calculating using NHANES III 
13. Time to first rescue analgesia post injection 
14. Medications during first 24 hours of hospital stay 
1. 24 hour total morphine milligram equivalent consumption 
1. Calculated based on CDC Morphine Milligram Equivalence 
(MME) Calculator: 
https://www.cdc.gov/drugoverdose/prescribing/app.html 
2. Any antimetics used after injection within 24 hours after enrollment 
3. Time to administration of first rescue analgesia post injection 
15. Nerve Block performed during inpatient stay 
1. List date/time/type of any additional nerve blocks performed for rib 
fracture pain after the study injection during the patient’s hospital stay 
16. Pulmonary complications:  
1. New O2 requirement, BIPAP or intubation, transfer to ICU for respiratory 
issue, development of pneumonia, readmission for pulmonary issue, new 
need for home O2 
17. Nerve Block Complications 
1. Development of cellulitis at site of block during hospital stay 
2. Pneumothorax occurring within 12 hours of injection 
18. Discharge Data 
1. If cellulitis developed at the site of injection during hospital stay 
2. If a pneumothorax on the same side of the injection occurred within 12 
hours of block 
 
19. Imaging 
1. Videos of the nerve block performance will be recorded in each patient. 
These images will later be de-identified and reviewed by two independent 
reviewers not involved in the study to determine visually whether the planar 
spread of anesthetic was correctly placed or not correctly placed. 
 
 
Data Analysis:   
For the primary endpoint of increase in vital capacity at 3-6 hours and secondary outcome of 
change in pain score, we will be using t-tests to compare groups. Differences in complication and 

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side effect rates will be summarized and compared using a chi-square test or fisher exact test if 
applicable.  
 
Sample Size:  
 
III. 
Sample Size: 90 total (45 for each group) 
1. Based on Mackersie et al, patients with epidural analgesia had a 5.1cc/kg 6.5 
increase in vital capacity before and after analgesia. Using 5.1cc/kg, we entered 
this value into the NHANES III calculator for a 60 kg person, with an average 
height of 177cm, ethnicity as caucasian, and an average age of 60. This gave us a 
value of 300mL or a 0.3L change in vital capacity after the nerve block which 
translated into a % predicted value of 6.4%. We therefore assumed that the nerve 
block would improve the % predicted value of vital capacity by around 6 
percentage points. 
2. Based on data obtained by Carver et al, the mean baseline % predicted vital 
capacity for 30 people in the emergency department was around 34 with SD=8. 
We assumed a greater variability of 10 for SD. These patients did not receive 
nerve blocks within the first 24 hours, had unilateral rib fractures, with GCS>13 
and the ability to perform vital capacity measurements. We thus considered this 
group similar to our sham group receiving standard therapy. At 3 and 6 hour 
follow-up for this group, there was no change in the vital capacity with a range of 
1-2 percentage point variation between the two values. Since within subject 
variations of 2.3-3.6% have been reported in the literature, we viewed the 1-2% 
variations as not significant (Kunzli). 
3. If we expect no change in the standard group, based on measurements between 3 
and 6 hours follow-up, and we expect to see a positive effect size of 6 points in 
the nerve block group, with 80% power and alpha of 0.05, we would need 45 
people per group. 
Expected Outcomes:  
 
1. We expect that patients undergoing ultrasound guided SAPB will have a more 
significant improvement in percent predicted vital capacity, in pain control, and in 
side effect profile. We also expect that patients receiving SAPB will have 
significantly lower usage of opiates to treat their pain and will not have any 
increased rates of pulmonary complications. 
 
Adverse Events:   
 
Serious: 
Arrhythmia, cardiac arrest/collapse, possible nerve damage, seizure, 
syncope 
Common Side 
Effects: 
dizziness, nausea, vomiting, weakness or fatigue, sedation, altered mental 
state, decrease in heart rate and blood pressure, local anesthetic systemic 

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toxicity, vision change, tinnitus, shortness of breath, pruritus, 
numbness/tingling around the mouth or eyes (perioral & periorbital 
numbness), metallic taste in the mouth 
 
SAE Reporting:  Any serious adverse event, requiring intervention, will be reported to the 
IRB within 24 hours of discovery by the research staff. Less serious adverse events will be 
reported within a week of discovery.  
 
Data Safety Monitoring Board (DSMB): 
 
The DSMB consisting of study investigators and at least one member who is not an investigator 
on the study.  The DSMB will meet after patient 25 is enrolled in the study. The DSMB will review 
the data and any adverse events and submit a report to the IRB.   
 
REFERENCES 
1. Battle CE, Hutchings H, Evans PA. Risk factors that predict mortality in patients 
with blunt chest wall trauma: a systematic review and meta-analysis. Injury, Int. J. 
Care Injured. 2012;43:8-17. 
2. Blanco R, Parras T, McDonnell JG, Prats-Galino A. Serratus plane block: a novel 
ultrasound-guided thoracic wall nerve block. Anaesthesia. 2013;68:1107-1113. 
3. Carver TW, Milia DJ, Somberg C, Brasel K, Paul J. Vital capacity helps predict 
pulmonary complications after rib fractures. J Trauma Acute Care 
Surg. 2015;79(3):413-6. 
4. Di Gregorio GD, Neal JM, Rosenquist RW, Weinberg GL. Clinical presentation 
of local anesthetic systemic toxicity. Reg Anesth Pain Med. 2010;35:181-187. 
5. Dittmann M, Keller R, Wolff G. A rationale for epidural analgesia in the 
treatment of multiple rib fractures. Intens Care Med. 1978;4:193-197. 
6. Durant E, Dixon B, Luftig J, Mantuani D, Herring A. Ultrasound-guided serratus 
plane block for ED rib fracture pain control. AJEM. 2017;197.e3-e6. 
7. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a 
sample of the general U.S. population. Am J Respir Crit Care Med. 
1999;159:179-187. 
8. Hetta DF, Rezk KM. Pectoralis-serratus interfascial plane block vs thoracic 
paravertebral block for unilateral radical mastectomy with axillary evacuation. J 
Clin Anesth. 2016;34:91-97. 
9. Khalil AE, Abdallah NM, Bashandy GM, Kaddah TA, et al. Ultrasound-guided 
serratus anterior plane block versus thoracic epidural analgesia for thoracotomy 
pain. J Cardiothorac Vasc Anesth. 2017;31:152-158. 
10. Mackersie RC, Karagianes TG, Hoyt DB, Davis JW. Prospective evaluation of 
epidural and intravenous administration of fentanyl for pain control and 
restoration of ventilatory function following multiple rib fractures. J Trauma. 
1991;31(4):443-451. 

Maimonides Medical Center Protocol March 4, 2021  
 Page 11 of 11 
 
11. Mayes J, Davidson E, Panahi P, Patten D, Eljelani F, Womack J, et al. An 
anatomical evaluation of the serratus anterior plane block. Anaesthesia 
2016;71:1064-1069. 
12. Madabushi R, Tewari S, Gautam SK, Agarwal A, Agarwal A. Serratus anterior 
plane block: a new analgesic technique for post-thoracotomy pain. Pain Physician. 
2015;18(3):E421-424. 
13. Pellegrino R, Viegi G, Brusasco V, Crapo RO, Burgos F, Casaburi R, et al. 
Interpretive strategies for lung function tests. Eur Respir J. 2005;26:948-968. 
14. Kunzli N, Ackermann-Liebrich U, Keller R, Perruchoud AP, Schindler C, et al. 
Variability of FVC and FEV1 due to technician, team, device and subject in an 
eight centre study. Eur Respir J. 1995;8:371-376. 
15. Kunhabdulla NP, Agarwal A, Gaur A, Gautam SK, Gupta R, Agarwal A. Serratus 
anterior plane block for multiple rib fractures. Pain Physician. 2014;17(5):E651–
653.