High success rate of first-attempt emergency intubation seen in SG centre

A recent study has shown that senior trainees or fellows perform most of the emergency intubations for medical indications in a Singapore centre, using rapid sequence intubation (RSI) and video laryngoscopy, with good first-attempt success.

“Airway management is an essential skill for emergency physicians,” the researchers said. “Difficult airway management is a norm rather than an exception due to widespread obesity and acquired difficult airway characteristics that come with an ageing patient population.”

This prospective observational study was conducted for 31 months from 1 March 2016 to 28 September 2018. The researchers collected and described data in each intubation attempt, including indications for intubation, airway assessment, intubation techniques used, peri-intubation adverse events, and clinical outcomes.

A total of 669 patients (mean age, 60.9 years; 67.3 percent male) were included in the analysis, of whom 25.6 percent were obese or grossly obese and 84.8 percent were intubated due to medical indications. [Ann Acad Med Singap 2021;50:42-51]

Initial impression of difficult airway by emergency physicians was associated with a higher grade of glottis view on laryngoscopy. First-pass intubation success rate was 86.5 percent, with hypoxia (11.2 percent) and hypotension (3.7 percent) being the most common adverse events.

Physicians most frequently used RSI (67.3 percent) and a video laryngoscope (75.6 percent). More than half of the intubations were carried out by postgraduate clinicians in year 5 and above, clinical fellows, or attending physicians.

“In our cohort, RSI was the most common method used during first intubation attempts (67.3 percent), similar to the reported frequencies of RSI use in the US and Canada emergency departments (EDs),” the researchers said. [Ann Emerg Med 2005;46:328-336]

“RSI is the preferred method in the ED predominantly due to the patient population,” they added. [J Emerg Med 2011;41:347-354; Ann Emerg Med 1998;31:325-332; Emerg Med J 2006;23:54-56; Acad Emerg Med 1999;6:31-37; Ann Emerg Med 2015;65:363-370.e1]

In this Singapore centre, the more commonly used paralytic agent for RSI was succinylcholine (92.2 percent) as opposed to rocuronium (7.8 percent), which is likely cultural as the use of neuromuscular blocking agents (NMBAs) in the multicentre NEAR project is split evenly between the two agents.

“Historically, the majority of ED providers used succinylcholine as an NMBA due to its rapid onset of action, short duration of action, and presence of fasciculations, allowing physicians to visually determine the onset of muscle paralysis,” the researchers said. [Anaesthesia 2017;72:765-777]

“However, in several pathological states that upregulate muscle nicotinic acetylcholine receptors—such as direct muscle trauma, physical or chemical denervation, muscle relaxants, or toxins and burns—the risk of succinylcholine-induced hyperkalaemia is high,” they added. [Anesthesiology 2006;104:158-169]

Furthermore, the increasing number of older patients in the ED was a cause for concern in airway management. In the present study, the cohort had a median age of 60.9 years, which is higher than that of other studies. This is consistent with the increasing ageing population seen in Singapore’s healthcare system. [Eur J Emerg Med 2003;10:209-212; Gerontologist 2019;59:401-410]

“Ageing is associated with changes in the airway manifested through edentulous mouth, glottic muscle atrophy and reduced neck mobility, which increases the difficulty of ventilation and intubation,” the researchers said. [Clin Interv Aging 2015;10:1925-1934]

Intubation in the ED are often performed immediately without the benefit of preselection or the ability to defer, according to the researchers.