Adherence to vasopressor guidance in emergency intubation relies on shock‐stratified denominators

Ramasamy et al. [1] provide a valuable contemporary account of emergency tracheal intubation outside UK operating theatres. They report that 105/233 patients received no pre-emptive vasopressor and that 40 of these subsequently required one. Together with the observed propofol doses, these findings inform their conclusion that practice deviates from guidance. Our concern is not propofol dosing, but the inference of vasopressor non-adherence, which depends on the denominator used to define patients for whom pre-induction treatment was indicated. The underpinning guidance distinguishes preparation from treatment. It requires that a vasopressor or inotrope be immediately available for bolus or infusion during induction and tracheal intubation, but states only that in shock states, a vasopressor should also be considered before induction [2]. Accordingly, universal prophylaxis is not mandated. More recent Society of Critical Care Medicine guidance found insufficient evidence to determine whether peri-intubation vasopressors, compared with intravenous fluid, reduce worsening hypotension or cardiac arrest in hypotensive critically ill adults undergoing rapid sequence induction [3]. The absence of a pre-emptive vasopressor in an unselected cohort therefore cannot establish non-adherence unless the patients in shock are identified explicitly. In the NoTHREAT cohort, 56 (24%) patients had pre-existing cardiovascular instability, and cardiovascular instability was an indication for intubation in 32 (14%) [1]. Neither category is synonymous with shock, but they are the closest reported patient group. The overlap between these patients and the 105 patients classified as receiving no pre-emptive vasopressor is not reported, nor are vasopressor practice and haemodynamic outcomes cross-tabulated within this clinically relevant sub-group. We also note an apparent numerical discrepancy, as Table 3 records 111 (48%) patients as receiving no vasopressor with induction, whereas the text reports 105 (45%) [1]. Clarifying whether the six-patient difference reflects patients already receiving vasopressor infusions before induction, or another classification decision, is important because it determines the untreated denominator and the 40/105 proportion derived from it. Subsequent vasopressor administration does not resolve this uncertainty. It may indicate treatment of clinically important hypotension, but could also represent an anticipatory bolus, escalation of an existing infusion or treatment initiated before systolic pressure fell below 80 mmHg. In INTUBE, lower pre-induction systolic pressure and other physiological abnormalities identified the patients at greatest risk of peri-intubation cardiovascular collapse [4]. More directly, Fuchita et al. compared 187 propensity-matched pairs of critically ill patients, although their hypotension threshold (systolic blood pressure below 90 mmHg between induction and 2 min after intubation) differed from that used in NoTHREAT [5]. They found that prophylactic vasopressors were not associated with less peri-intubation hypotension (41% with vs. 32% without, p = 0.08), a direction that is likely to reflect confounding by indication. Residual confounding notwithstanding, these findings caution against treating later vasopressor use as proof of a missed prophylactic opportunity. To strengthen the clinical message from Ramasamy et al., we encourage the authors to extend that stratification to vasopressor practice and to clarify the 105/111 denominator discrepancy, reporting corresponding rates of new severe hypotension and cardiac arrest within the cardiovascular instability sub-group. This would require no new data collection and would address the clinically relevant denominator directly. Vasopressors should be immediately available for every emergency intubation; however, standardised protocols should specify shock-specific criteria for pre-induction administration. Without such criteria, a protocol risks institutionalising universal prophylaxis that current evidence does not support.