Episode 868: Airway Management in Obesity

09/11/23 • 3 min

1 Listener

Emergency Medical Minute

Contributor: Aaron Lessen MD

Educational Pearls:

Why is airway management more difficult in obesity?

Larger body habitus causes the chest to be above the head when the patient is lying supine, creating difficult angles for intubation.
Reduced Functional Residual Capacity (FRC) causes these patients to deoxygenate much more quickly, reducing the amount of time during which the intubation can take place.

What special considerations need to be made?

Positioning. The auditory canal and sternal notch should be aligned in a horizontal plane. Do this by stacking blankets to lift the neck and head. Also, try to make the head itself parallel to the ceiling.
Pre-oxygenation. Use Bi-level Positive Airway Pressure (BiPAP) with Positive End Expiratory Pressure (PEEP) or a Bag-Valve-Mask (BVM) with a PEEP valve. PEEP helps prevent alveoli from collapsing after every breath and improves oxygenation.
Dosing of paralytics. Succinylcholine is dosed on total body weight so the dose will be much larger for the obese patient. Rocuronium is dosed on ideal body weight, but adjusted body weight may also be used in obese cases.

References

De Jong A, Wrigge H, Hedenstierna G, Gattinoni L, Chiumello D, Frat JP, Ball L, Schetz M, Pickkers P, Jaber S. How to ventilate obese patients in the ICU. Intensive Care Med. 2020 Dec;46(12):2423-2435. doi: 10.1007/s00134-020-06286-x. Epub 2020 Oct 23. PMID: 33095284; PMCID: PMC7582031.
Langeron O, Birenbaum A, Le Saché F, Raux M. Airway management in obese patient. Minerva Anestesiol. 2014 Mar;80(3):382-92. Epub 2013 Oct 14. PMID: 24122033.
Sharma S, Arora L. Anesthesia for the Morbidly Obese Patient. Anesthesiol Clin. 2020 Mar;38(1):197-212. doi: 10.1016/j.anclin.2019.10.008. Epub 2020 Jan 2. PMID: 32008653.
Singer BD, Corbridge TC. Basic invasive mechanical ventilation. South Med J. 2009 Dec;102(12):1238-45. doi: 10.1097/SMJ.0b013e3181bfac4f. PMID: 20016432.

Summarized by Jeffrey Olson, MS2 | Edited by Jorge Chalit, OMSII

Contributor: Aaron Lessen MD

Educational Pearls:

Why is airway management more difficult in obesity?

Larger body habitus causes the chest to be above the head when the patient is lying supine, creating difficult angles for intubation.
Reduced Functional Residual Capacity (FRC) causes these patients to deoxygenate much more quickly, reducing the amount of time during which the intubation can take place.

What special considerations need to be made?

Positioning. The auditory canal and sternal notch should be aligned in a horizontal plane. Do this by stacking blankets to lift the neck and head. Also, try to make the head itself parallel to the ceiling.
Pre-oxygenation. Use Bi-level Positive Airway Pressure (BiPAP) with Positive End Expiratory Pressure (PEEP) or a Bag-Valve-Mask (BVM) with a PEEP valve. PEEP helps prevent alveoli from collapsing after every breath and improves oxygenation.
Dosing of paralytics. Succinylcholine is dosed on total body weight so the dose will be much larger for the obese patient. Rocuronium is dosed on ideal body weight, but adjusted body weight may also be used in obese cases.

References

De Jong A, Wrigge H, Hedenstierna G, Gattinoni L, Chiumello D, Frat JP, Ball L, Schetz M, Pickkers P, Jaber S. How to ventilate obese patients in the ICU. Intensive Care Med. 2020 Dec;46(12):2423-2435. doi: 10.1007/s00134-020-06286-x. Epub 2020 Oct 23. PMID: 33095284; PMCID: PMC7582031.
Langeron O, Birenbaum A, Le Saché F, Raux M. Airway management in obese patient. Minerva Anestesiol. 2014 Mar;80(3):382-92. Epub 2013 Oct 14. PMID: 24122033.
Sharma S, Arora L. Anesthesia for the Morbidly Obese Patient. Anesthesiol Clin. 2020 Mar;38(1):197-212. doi: 10.1016/j.anclin.2019.10.008. Epub 2020 Jan 2. PMID: 32008653.
Singer BD, Corbridge TC. Basic invasive mechanical ventilation. South Med J. 2009 Dec;102(12):1238-45. doi: 10.1097/SMJ.0b013e3181bfac4f. PMID: 20016432.

Summarized by Jeffrey Olson, MS2 | Edited by Jorge Chalit, OMSII

Previous Episode

Episode 867: Occult Scaphoid Fractures

1 Recommendations

Contributor: Nick Tsipis MD

Educational Pearls:

The scaphoid bone is the most proximal carpal bone just distal to the radius
Fractures of the scaphoid bone are sometimes missed by plain X-rays

A 2020 review found a 21.8% incidence of missed scaphoid fractures later diagnosed by advanced imaging modalities
Only MRI has a sensitivity above 90% for diagnosing scaphoid fractures
Sensitivity of plain-film radiography is low unless it is a displaced fracture

Physical examination techniques fail to definitively rule out scaphoid fractures
A 2023 systematic review assessed the sensitivity and specificity of several common physical exam maneuvers:

Tenderness of the anatomical snuffbox has a sensitivity of 92.1% and specificity of 48.4%; i.e. absence reduces the likelihood of an occult scaphoid fracture but does not rule it out
Another common physical exam maneuver is pain with ulnar deviation, which carries a sensitivity of 55.2% and specificity of 76.4%.
Elicitation of pain with supination against resistance demonstrated a sensitivity of 100% and specificity of 97.9% in the study, so the authors recommend externally validating this method

Patients should be counseled on the importance of follow-up given that a fracture may not show up on imaging unless an MRI or repeat XR is done

References

1. Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020;09(01):081-089. doi:10.1055/s-0039-1693147

2. Coventry L, Oldrini I, Dean B, Novak A, Duckworth A, Metcalfe D. Which clinical features best predict occult scaphoid fractures? A systematic review of diagnostic test accuracy studies. Emerg Med J. 2023;40(8):576 LP - 582. doi:10.1136/emermed-2023-213119

Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit, OMSII

Next Episode

Podcast 869: Shift Work

Contributor: Meghan Hurley MD

Educational Pearls:

Shift work is defined as anything that takes place outside of a 9-5 schedule, not exempting day-shift medical workers
Various ill effects of shift work on overall health:

Increased all-cause mortality
Increased number of accidents
Glucose metabolism dysregulation
Increased BMI
Fertility impacts for men and women
Increased breast cancer risk
Decreased cognitive functioning

Mitigation strategies

Work at the same time every day
Anchor Sleep - always try to be asleep at the same time of day
Progressive shifts: day- into swing- into night shift instead of the other way around
Three days off after a stretch of nights can help reset sleep schedule
Shorter night shifts
Morning shifts should start no earlier than 8 AM

Sleep hygiene

Ensure an ideal sleep environment; cool, dark, and damp
Avoid bright lights when going to sleep
Exposure to bright lights when waking up
Hydration throughout your shift
Stop caffeine at midnight if you are working a night shift
Eat healthy meals and avoid junk food
Avoid eating 2-3 hours before going to sleep

References

Boivin, D. B., Boudreau, P., & Kosmadopoulos, A. (2022). Disturbance of the Circadian System in Shift Work and Its Health Impact. Journal of biological rhythms, 37(1), 3–28. https://doi.org/10.1177/07487304211064218
Jang TW. Work-Fitness Evaluation for Shift Work Disorder. Int J Environ Res Public Health. 2021;18(3):1294. Published 2021 Feb 1. doi:10.3390/ijerph18031294
Minors DS, Waterhouse JM. Anchor sleep as a synchronizer of rhythms on abnormal routines. Int J Chronobiol. 1981;7(3):165-188.
Reinganum MI, Thomas J. Shift Work Hazards. [Updated 2023 Jan 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK589670/

Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit, OMSII