Aspiration during Rapid Sequence Induction: Prevalence and Risk Factors

INTRODUCTION

The emergency department (ED) is considered as the face of the hospital and first line of contact to health care for the critically ill.¹ The success of resuscitation of critically ill patients reflects the standards of the ED. Endotracheal intubation is considered as the gold standard airway management in the ED for patient requiring definitive airway.² It is one of the most commonly performed invasive procedures in the ED. Due to limited time for preparation, unstable condition of the patient, and urgency of the situation, it is always considered as a high-risk procedure.³ A 12-26% intubation-related adverse events have been reported in the literature.^4-6 RSI includes the use of an induction agent, followed by a paralytic agent to achieve optimal conditions for intubation. This drug regimen should produce sedation and neuromuscular paralysis, maintain hemodynamic stability, and prevent vomiting.⁷ Drugs with rapid onset, short duration of action, and minimal adverse effects are usually administered.

Aspiration is defined as the inhalation of either oral, pharyngeal, or gastric contents into the lower airways.⁸ This can lead to a number of syndromes based on the quantity and nature of the aspirated material, the frequency of aspiration, and the host factors that predispose the patient to aspiration and modify the response.⁸ The epidemiological study on AP is complicated due to lack of specific and sensitive marker to diagnose AP and difficulty to distinguish between aspiration syndromes(aspiration pneumonitis and AP).⁹ The diagnosis of AP is made when a patient at risk for aspiration is found to have a radiographic evidence of an infiltrate in a characteristic bronchopulmonary segment.¹⁰ The course of the disease is similar to that of a typical community-acquired pneumonia, but has a higher risk of developing cavitation and abscess formation, if left unrecognized or untreated.¹⁰ Pepsin is the major proteinase in the stomach secreted by the chief cells. It is normally absent in the respiratory tract. So the presence of pepsin in the respiratory tract implies that aspiration had occurred. Also, the ET aspirate will contain gastric contents if they were aspirated and this can be used to demonstrate the presence of pepsin.¹¹ In general, there is a higher risk of aspiration and developing other complications among patients intubated in the ED compared to those in intensive care units (ICUs) and operating rooms (ORs).¹² Hence, we conducted this study to determine the prevalence and risk factors for the development of AP in patients who undergo RSI in the ED and to determine the sensitivity and specificity of pepsin to aid the diagnosis of AP.

MATERIALS AND METHODS

RESULTS

A total of 47,629 patients presented to our ED during the study period. We screened all 338 patients requiring RSI in the ED, and 184(54%) patients were excluded as they did not fulfill the inclusion criteria, leaving 154 patients for further analysis (Flowchart 1).

DISCUSSION

Our study showed that the prevalence of AP secondary to endotracheal intubation in the ED was 13.4%. We did not identify any intubation factors that predisposed to the development of AP. ET aspirate pepsin assay had a very low sensitivity and specificity in predicting the occurrence of AP. The occurrence of aspiration of gastric contents following endotracheal intubation in the ED varies from 1% to 20% according to known literature.^15-20 This variation in results may be attributed due to the lack of clear definition of AP. The end points of AP as described in previous studies too were questionable. These included (i) suspicion of aspiration, (ii) witnessed aspiration, (iii) radiographic changes, such as the presence of infiltrates, (iv) sputum cultures, and (v) arterial blood gas analysis, none of which were found to have high sensitivity or specificity for detecting aspiration.⁸

The mean age (44.5 years) of our study population was much lesser than the median age in a study done by Lanspa et al. study (77).²¹ The difference in age distribution could be attributed to the fact that in developed countries where the study was done, the life expectancy is longer; hence, the proportion of patients in their study is skewed toward older and more comorbid population. Similar to the findings of Driver et al., none of the factors associated with RSI, such as premedications, paralyzing agents, use of video and direct laryngoscope, the number of attempts to intubate, experience of the intubator, the Cormack-Lehane grading of the vocal cords, and application of cricoid pressure prior to intubation proved to be significant risk factors for the development of AP.¹³ This is perhaps attributable to the study done in a well-established teaching center with supervision, in contrast to majority of hospitals that depend on junior medical officers for managing compromised airways. Though higher use of video laryngoscopy probably resulted in a higher first-attempt success rate, it did not decrease the rate of AP.¹³ The adverse events profile in our study was similar to that seen in other studies.²²

Data from other studies have revealed that tracheal aspirate pepsin is a reliable marker to diagnose aspiration.^11,23-25 The qualitative detection of pepsin, by demonstrating pepsin activity on exposure to pepstatin (pepsin inhibitor), proved to be highly sensitive and specific by Ufberg et al.¹¹ In our study, quantitative assessment of pepsin from ET aspirate was done and had low sensitivity. Negative pepsin assay in almost half of the patients who developed AP may be due to microaspiration that occurred following ET aspirate collection.

STRENGTHS

This was a prospective study with all consecutive patients requiring RSI being enrolled, thereby minimizing the bias. Quantitative assessment of ET aspirate pepsin levels was another strength of our study.

CLINICAL SIGNIFICANCE

The ET aspirate pepsin assay used in our study was a research kit. There might be variation in results with respect to the research kits.

LIMITATIONS

In our study, we could not reach the required sample size of 174, mainly because the Human Pepsin ELISA Kit used could not be imported from China due to travel and transport disruptions during the COVID-19 pandemic.

CONCLUSION

From our study, we concluded that male gender and diabetes mellitus were independent risk factors for the development of AP following RSI in the ED. The role of ET aspirate pepsin levels to predict the occurrence of AP did not yield promising results.

ORCID

Ramgopal Roshan https://orcid.org/0000-0002-2799-3781

Sudhakar G Dhanapal https://orcid.org/0000-0001-8323-6075

Joshua Vijay https://orcid.org/0000-0002-9501-4995

Mamta Madhiyazhagan https://orcid.org/0000-0001-9163-6212

Jayakumar Amirtharaj https://orcid.org/0000-0001-6788-6879

Priya Ganesan https://orchid.org/0000-0001-6542-3766

Kundavaram PP Abhilash https://orcid.org/0000-0002-2382-4411

REFERENCES

1. Jain A, Sase NN, Mathew AR, Paul IJ, Abhilash Kundavaram PP, Ganesan P. Last breath in the emergency department. J Emerg Trauma Shock 2019;12(4):263–267. DOI: 10.4103/JETS.JETS_147_18.

2. Stevenson AGM, Graham CA, Hall R, Korsah P, McGuffie AC. Tracheal intubation in the emergency department: the Scottish district hospital perspective. Emerg Med J 2007;24(6):394–397. DOI: 10.1136/emj.2006.041988.

3. Inoue A, Okamoto H, Hifumi T, Goto T, Hagiwara Y, Watase H, et al. The incidence of post-intubation hypertension and association with repeated intubation attempts in the emergency department. PLoS ONE 2019;14(2):e0212170. DOI: 10.1371/journal.pone.0212170.

4. Brown CA, Bair AE, Pallin DJ, Walls RM. Techniques, success, and adverse events of emergency department adult intubations. Ann Emerg Med 2015;65(4):363–370.e1. DOI: 10.1016/j.annemergmed.2014.10.036.

5. Alkhouri H, Vassiliadis J, Murray M, Mackenzie J, Tzannes A, McCarthy S, et al. Emergency airway management in Australian and New Zealand emergency departments: a multicentre descriptive study of 3710 emergency intubations. Emerg Med Australas 2017;29(5):499–508. DOI: 10.1111/1742-6723.12815.

6. Goto Y, Goto T, Hagiwara Y, Tsugawa Y, Watase H, Okamoto H, et al. Techniques and outcomes of emergency airway management in Japan: an analysis of two multicentre prospective observational studies, 2010–2016. Resuscitation 2017;11414–20. DOI: 10.1016/j.resuscitation.2017.02.009.

7. Dunham MC, Barraco RD, Clark DE, Daley BJ, Davis FE 3rd, Gibbs MA, et al. Guidelines for emergency tracheal intubation immediately after traumatic injury. J Trauma 2003;55(1):162–179. DOI: 10.1097/01.ta.0000083335.93868.2c.

8. Marik PE. Aspiration pneumonitis and aspiration pneumonia. N Engl J Med 2001;344(9):665–671. DOI: 10.1056/NEJM200103013440908.

9. Gómez J, Baños V, Ruiz Gómez J, Soto MC, Muñoz L, Nuñez ML, et al. Prospective study of epidemiology and prognostic factors in community-acquired pneumonia. Eur J Clin Microbiol Infect Dis 1996;15(7):556–560. DOI: 10.1007/BF01709363.

10. Bartlett JG, Gorbach SL, Finegold SM. The bacteriology of aspiration pneumonia. Am J Med 1974;56(2):202–207. DOI: 10.1016/0002-9343(74)90598-1.

11. Ufberg JW, Bushra JS, Patel D, Wong E, Karras DJ, Kueppers F. A new pepsin assay to detect pulmonary aspiration of gastric contents among newly intubated patients. Am J Emerg Med 2004;22(7):612–614. DOI: 10.1016/j.ajem.2004.08.019.

12. Martin LD, Mhyre JM, Shanks AM, Tremper KK, Kheterpal S. 3,423 emergency tracheal intubations at a university hospitalairway outcomes and complications. Anesthesiology 2011;114(1):42–48. DOI: 10.1097/ALN.0b013e318201c415.

13. Driver BE, Klein LR, Schick AL, Prekker ME, Reardon RF, Miner JR. The occurrence of aspiration pneumonia after emergency endotracheal intubation. Am J Emerg Med 2018;36(2):193–196. DOI: 10.1016/j.ajem.2017.07.066.

14. Lindenauer PK, Strait KM, Grady JN, Ngo CK, Parisi ML, Metersky M, et al. Variation in the diagnosis of aspiration pneumonia and association with hospital pneumonia outcomes. Ann Am Thorac Soc 2018;15(5):562–569. DOI: 10.1513/AnnalsATS.201709-728OC.

15. Schwar tz DE, Mat thay MA, Cohen NH. Death and other complications of emergency airway management in critically ill adults. A prospective investigation of 297 tracheal intubations. Anesthesiology 1995;82(2):367–376. DOI: 10.1097/00000542-199502000-00007.

16. Oswalt JL, Hedges JR, Soifer BE, Lowe DK. Analysis of trauma intubations. Am J Emerg Med 1992;10(6):511–514. DOI: 10.1016/0735-6757(92)90173-U.

17. Thibodeau LG, Verdile VP, Bartfield JM. Incidence of aspiration after urgent intubation. Am J Emerg Med 1997;15(6):562–565. DOI: 10.1016/S0735-6757(97)90157-1.

18. Ja R, Dh L, Bj T, Jr RB. The value of intubating and paralyzing patients with suspected head injury in the emergency department. J Trauma 1991;31(3):371–375. DOI: 10.1097/00005373-199103000-00010.

19. Rashkin MC, Davis T. Acute complications of endotracheal intubation: relationship to reintubation, route, urgency, and duration. Chest 1986;89(2):165–167. DOI: 10.1378/chest.89.2.165.

20. Taryle DA, Chandler JE, Good JT, Potts DE, Sahn SA. Emergency room intubations—complications and survival. Chest 1979;75(5):541–543. DOI: 10.1378/chest.75.5.541.

21. Lanspa MJ, Jones BE, Brown SM, Dean NC. Mortality, morbidity, and disease severity of patients with aspiration pneumonia. J Hosp Med 2013;8(2):83–90. DOI: 10.1002/jhm.1996.

22. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg 2004;99(2):607–613. DOI: 10.1213/01.ANE.0000122825.04923.15.

23. Ufberg JW, Bushra JS, Karras DJ, Satz WA, Kueppers F. Aspiration of gastric contents: association with prehospital intubation. Am J Emerg Med 2005;23(3):379–382. DOI: 10.1016/j.ajem.2005.02.005.

24. Krishnan U, Mitchell JD, Messina I, Day AS, Bohane TD. Assay of tracheal pepsin as a marker of reflux aspiration. J Pediatr Gastroenterol Nutr 2002;35(3):303–308. DOI: 10.1097/00005176-200209000-00012.

25. Metheny NA, Chang YH, Ye JS, Edwards SJ, Defer J, Dahms TE, et al. Pepsin as a marker for pulmonary aspiration. Am J Crit Care 2002;11(2):150–154. DOI: 10.4037/ajcc2002.11.2.150.