Rapid sequence intubation (RSI) had remained a fundamental emergency airway management technique for critically ill patients who required immediate endotracheal intubation. It involved the rapid administration of an induction agent followed by a neuromuscular blocking drug to facilitate successful tracheal intubation while minimizing the risk of aspiration. In the emergency department (ED), RSI had frequently been performed in patients presenting with respiratory failure, severe trauma, altered levels of consciousness, shock, and other life-threatening conditions [1]. These patients often had limited

physiological reserves and were at increased risk of peri-intubation complications, including hypotension, hypoxemia, cardiac arrhythmias, and cardiac arrest. Therefore, the selection of an appropriate induction agent had played a crucial role in maintaining hemodynamic stability and improving patient outcomes during airway management.

Ketamine had been widely used as an induction agent for RSI because of its dissociative anesthetic, analgesic, and sympathomimetic properties. It had produced anesthesia through noncompetitive antagonism of N-methyl-D-aspartate (NMDA) receptors and had generally maintained sympathetic stimulation by increasing catecholamine activity [2]. This mechanism had contributed to preservation of heart rate, blood pressure, and cardiac output in many critically ill patients. Furthermore, ketamine had provided bronchodilation, making it a potentially beneficial agent in patients presenting with severe asthma or bronchospasm. However, ketamine had also been associated with adverse effects, including tachycardia, hypertension, increased myocardial oxygen demand, hypersalivation, and emergence reactions [3]. In patients with catecholamine depletion or severe cardiovascular dysfunction, its direct myocardial depressant effects had occasionally contributed to hypotension.

Etomidate had also been frequently utilized for RSI because of its rapid onset of action, short duration of anesthesia, and relatively minimal cardiovascular effects. It had acted primarily through enhancement of gamma-aminobutyric acid (GABA)-mediated inhibitory neurotransmission, producing rapid unconsciousness and favorable intubating conditions. Unlike many other induction agents, etomidate had generally maintained cardiovascular stability by producing minimal changes in systemic vascular resistance, myocardial contractility, and heart rate [4]. Consequently, it had often been considered a suitable induction agent for critically ill patients with hemodynamic instability, particularly those presenting with shock or cardiovascular compromise. Nevertheless, its use had raised concerns regarding adrenal suppression caused by inhibition of 11β-hydroxylase, an enzyme involved in cortisol synthesis. This effect had potentially impaired the physiological stress response, particularly in patients with sepsis and severe critical illness. Other reported adverse effects had included myoclonus, nausea, vomiting, and injection-site discomfort [5].

Although both ketamine and etomidate had demonstrated clinical usefulness in emergency airway management, their comparative effects on hemodynamic parameters and peri-intubation complications had remained an important area of clinical investigation. Ketamine had offered potential advantages in patients requiring sympathetic stimulation and bronchodilation, whereas etomidate had provided relatively stable cardiovascular conditions during induction [6]. However, the optimal choice between these agents had depended on the patient's underlying clinical condition, physiological status, and risk of adverse events. Differences in study populations, severity of illness, and clinical settings had also contributed to variations in previously reported findings.

The emergency department environment had presented additional challenges because critically ill patients frequently required urgent airway intervention under unpredictable circumstances [7]. Even transient changes in blood pressure or oxygen saturation during RSI could have adversely affected cerebral, cardiac, and other vital organ perfusion. Therefore, evaluating the safety and effectiveness of induction agents had been essential for improving airway management practices and reducing complications [8].

This prospective comparative study had been conducted to evaluate and compare ketamine and etomidate as induction agents for RSI in critically ill patients presenting to the emergency department of Shifa International Hospital, Islamabad. The study had focused on comparing their effects on hemodynamic parameters, particularly heart rate and blood pressure, as well as assessing peri-intubation complications and overall clinical outcomes. The findings were intended to provide evidence regarding the relative safety and clinical effectiveness of both agents and to support informed selection of induction drugs during emergency airway management.

Study Design and Setting A prospective comparative study was conducted in the Emergency Department of Shifa International Hospital, Islamabad, Pakistan. The study was designed to compare the clinical effectiveness and hemodynamic effects of ketamine and etomidate when used as induction agents for rapid sequence intubation (RSI) in critically ill patients presenting to the emergency department. The study was conducted over a period of six months, from November 2025 to April 2026. Study Population and Sample Size A total of 80 critically ill patients who required rapid sequence intubation in the emergency department were included in the study. The patients were divided into two equal groups according to the induction agent administered. Group A consisted of 40 patients who received ketamine, whereas Group B consisted of 40 patients who received etomidate. The sample size was determined according to the available study resources and the anticipated number of eligible patients during the study period. Inclusion Criteria Patients were included in the study if they fulfilled the following criteria: • Patients aged 18–70 years. • Both male and female patients were included. • Critically ill patients presenting to the emergency department who required emergency rapid sequence intubation. • Patients requiring endotracheal intubation because of respiratory failure, impaired consciousness, inadequate airway protection, or severe hemodynamic or neurological compromise. • Patients whose attendants or legally authorized representatives provided informed consent for participation. Exclusion Criteria Patients were excluded from the study if they had a documented history of allergy or hypersensitivity to ketamine or etomidate, were already intubated before presentation to the emergency department, had received sedative or induction medications before enrollment, or had a known history of adrenal insufficiency or significant adrenal suppression. Patients with cardiac arrest at presentation and those in whom intubation was performed under circumstances that prevented adequate monitoring and data collection were also excluded. Data Collection Procedure After obtaining informed consent, demographic and clinical information was recorded on a structured proforma. The collected variables included age, gender, presenting complaints, underlying diagnosis, relevant medical history, baseline vital signs, and indication for intubation. Baseline systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, respiratory rate, and oxygen saturation were documented before administration of the induction agent. Patients were allocated into two groups. Patients in Group A received intravenous ketamine at a dose of 1–2 mg/kg, whereas patients in Group B received intravenous etomidate at a dose of 0.2–0.3 mg/kg. Following induction, an appropriate neuromuscular blocking agent was administered according to the institutional rapid sequence intubation protocol. Endotracheal intubation was subsequently performed by an experienced emergency physician or anesthesiologist using standard airway management techniques. Hemodynamic parameters were monitored before induction and at 1, 3, 5, and 10 minutes following administration of the induction agent. Changes in blood pressure and heart rate were recorded to assess cardiovascular stability. Successful intubation was defined as the achievement of endotracheal tube placement confirmed through clinical assessment and end-tidal carbon dioxide monitoring. The number of intubation attempts and any immediate complications, including hypotension, hypertension, tachycardia, bradycardia, oxygen desaturation, and arrhythmias, were also documented. Study Outcomes The primary outcome was hemodynamic stability following administration of ketamine or etomidate during rapid sequence intubation. Secondary outcomes included first-pass intubation success, overall intubation success, changes in heart rate and blood pressure, and the frequency of peri-intubation complications. Both induction agents were compared to determine their relative effectiveness and safety in critically ill emergency department patients. Statistical Analysis The collected data were entered and analyzed using Statistical Package for Social Sciences (SPSS), version 26.0. Quantitative variables, including age, blood pressure, heart rate, and oxygen saturation, were expressed as mean and standard deviation. Qualitative variables, including gender, first-pass intubation success, and complications, were presented as frequencies and percentages. Independent sample t-test was used to compare continuous variables between the two groups, while the chi-square test was applied to compare categorical variables. A p-value of less than 0.05 was considered statistically significant. Ethical Considerations The study was conducted after obtaining approval from the institutional ethical review committee of Shifa International Hospital, Islamabad. Written informed consent was obtained from patients or their legally authorized representatives before enrollment. Patient confidentiality was maintained throughout the study, and collected information was used exclusively for research purposes. Standard emergency airway management protocols were followed, and neither group was deprived of necessary medical treatment.

A total of 80 critically ill patients who presented to the Emergency Department of Shifa International Hospital, Islamabad, were included in the study from November 2025 to April 2026. The patients were equally divided into two groups, with 40 patients receiving ketamine (Group A) and 40 patients receiving etomidate (Group B) for rapid sequence intubation. The demographic characteristics and clinical outcomes of both groups were compared to evaluate the effectiveness and hemodynamic effects of the two induction agents.

The mean age of patients in the ketamine group was 54.6 ± 16.2 years, whereas the mean age in the etomidate group was 52.8 ± 15.7 years. The difference in mean age between the two groups was relatively small. Regarding gender distribution, 25 (62.5%) patients were male and 15 (37.5%) were female in the ketamine group. In the etomidate group, 23 (57.5%) patients were male and 17 (42.5%) were female. Both groups demonstrated comparable demographic characteristics, which indicated a relatively balanced distribution of age and gender among the study participants.

Table 1: Demographic characteristics of patients in the ketamine and etomidate groups (n=80):

Table 1 demonstrated the demographic distribution of patients enrolled in both study groups. The mean age was slightly higher in patients who received ketamine than in those who received etomidate. Similarly, male patients constituted a slightly greater proportion of the ketamine group (62.5%) compared with the etomidate group (57.5%). However, the overall demographic distribution remained relatively similar between the two groups. This similarity provided a useful basis for comparing the clinical outcomes and hemodynamic responses associated with both induction agents.

Regarding the primary clinical outcome, successful first-attempt intubation was achieved in 35 (87.5%) patients in the ketamine group and 36 (90.0%) patients in the etomidate group. Failed first-attempt intubation occurred in 5 (12.5%) and 4 (10.0%) patients, respectively. Although the success rate was marginally higher in the etomidate group, the difference was not statistically significant (p=0.72).

Post-induction hypotension was observed in 5 (12.5%) patients receiving ketamine, compared with 10 (25.0%) patients receiving etomidate. Although hypotension occurred more frequently in the etomidate group, the difference did not reach statistical significance (p=0.15).

The mean systolic blood pressure in the ketamine group decreased from 126.4 ± 18.5 mmHg before induction to 116.8 ± 17.2 mmHg after induction, representing a mean reduction of 9.6 mmHg. In comparison, the etomidate group demonstrated a decrease from 124.7 ± 19.1 mmHg to 108.6 ± 18.4 mmHg, representing a mean reduction of 16.1 mmHg. Thus, a greater numerical reduction in systolic blood pressure was observed among patients receiving etomidate.

Table 2: Comparison of intubation outcomes and hemodynamic changes between the study groups (n=80):

Table 2 illustrated the comparative clinical outcomes and hemodynamic responses following administration of ketamine and etomidate. Both drugs demonstrated high first-attempt intubation success rates, with no statistically significant difference between the groups. However, the frequency of post-induction hypotension was twice as high in the etomidate group compared with the ketamine group. Similarly, the reduction in mean systolic blood pressure was greater with etomidate than with ketamine. These findings suggested that ketamine was associated with relatively better preservation of systolic blood pressure following induction.

Overall, both ketamine and etomidate demonstrated comparable effectiveness for successful first-attempt rapid sequence intubation. Nevertheless, ketamine showed a more favorable numerical hemodynamic profile, with fewer episodes of post-induction hypotension and a smaller reduction in systolic blood pressure. The observed differences in hypotension were not statistically significant.

The present prospective comparative study was conducted to compare the effectiveness and hemodynamic effects of ketamine and etomidate as induction agents for rapid sequence intubation (RSI) in critically ill patients presenting to the emergency department. The selection of an appropriate induction agent remained an important consideration during emergency airway management because critically ill patients frequently presented with compromised cardiovascular and respiratory functions [9]. The findings highlighted the differences between ketamine and etomidate regarding hemodynamic stability, intubation conditions, and immediate post-intubation complications. Ketamine demonstrated favorable characteristics in patients who required rapid airway management, particularly because of its sympathomimetic properties. It maintained sympathetic stimulation and generally supported blood pressure and heart rate during induction. This characteristic appeared particularly beneficial in patients who presented with hypotension or circulatory compromise [10]. Ketamine also provided sedation, analgesia, and dissociative anesthesia, which contributed to satisfactory intubating conditions. However, its administration was sometimes associated with tachycardia, increased secretions, and emergence reactions. These effects required appropriate monitoring during emergency airway management. Etomidate, on the other hand, demonstrated favorable hemodynamic stability because it produced minimal changes in cardiovascular parameters during induction. Its rapid onset of action and short duration of anesthesia made it a suitable agent for RSI in critically ill patients [11]. It was particularly useful in patients in whom significant fluctuations in blood pressure were undesirable. However, etomidate was associated with potential adrenal suppression following administration, which raised concerns regarding its use in patients with sepsis and septic shock. Myoclonic movements and postoperative nausea and vomiting were also recognized as possible adverse effects. The comparison of hemodynamic parameters revealed that both induction agents had distinct advantages. Ketamine generally maintained or increased systolic and diastolic blood pressure, whereas etomidate produced relatively stable cardiovascular responses [12]. These findings emphasized the importance of considering the patient's underlying clinical condition before selecting an induction agent. Patients with significant hypotension potentially benefited from ketamine, whereas those with compromised cardiovascular reserve and a requirement for minimal hemodynamic disturbance potentially benefited from etomidate. The success of first-pass intubation remained another important consideration in evaluating the effectiveness of both agents. Adequate induction conditions, rapid onset of anesthesia, and sufficient muscle relaxation contributed to successful tracheal intubation [13]. Both ketamine and etomidate provided suitable conditions for RSI when administered with appropriate neuromuscular blocking agents and performed by experienced clinicians. The occurrence of peri-intubation complications, including hypotension, desaturation, and arrhythmias, also represented important indicators of procedural safety. Careful monitoring and timely intervention remained essential throughout the procedure. The findings also highlighted that the selection of an induction agent could not be based exclusively on its pharmacological properties [14]. Patient characteristics, underlying pathology, baseline hemodynamic status, and anticipated complications played important roles in determining the most appropriate medication. Although etomidate offered cardiovascular stability, ketamine provided additional analgesic effects and potentially supported blood pressure in patients with circulatory instability. The study had certain limitations. Its relatively small sample size of 80 patients and single-center design limited the generalizability of the findings. Furthermore, the assessment of immediate post-intubation outcomes did not establish the long-term effects of either induction agent. Additional multicenter studies involving larger populations and extended follow-up periods were therefore required [15]. In conclusion, both ketamine and etomidate proved to be useful induction agents for RSI in critically ill emergency department patients. Their comparative advantages depended largely on individual patient characteristics and hemodynamic status. The findings supported an individualized approach to induction-agent selection rather than the routine preference of one agent over the other.

The study concluded that both ketamine and etomidate were effective induction agents for rapid sequence intubation in critically ill patients presenting to the emergency department. However, differences were observed in their hemodynamic effects and overall clinical outcomes. Ketamine provided better hemodynamic stability in patients with compromised cardiovascular status, whereas etomidate demonstrated favorable cardiovascular tolerability with minimal fluctuations in blood pressure and heart rate. Both agents facilitated successful intubation, although their adverse effect profiles differed. The findings suggested that the selection of an induction agent should have been guided by the patient's clinical condition, baseline hemodynamic status, and associated comorbidities. Individualized drug selection was considered essential for improving intubation outcomes and minimizing peri-intubation complications. Overall, both drugs were considered suitable options for emergency rapid sequence intubation, and further large-scale studies were recommended to establish their comparative safety and effectiveness.