European Journal of Cardiovascular Medicine

Rapid Sequence Intubation (RSI) is a cornerstone technique in emergency airway management, enabling swift and controlled endotracheal intubation while minimizing the risk of aspiration and hypoxia. Traditionally, RSI involves the administration of a potent sedative agent followed immediately by a neuromuscular blocking agent to facilitate optimal intubating conditions. However, this approach can result in significant hemodynamic fluctuations, particularly in critically ill patients with compromised physiological reserves (1,2).

Conscious sedation, defined as a medically controlled state of depressed consciousness that allows patients to maintain protective airway reflexes and respond to verbal commands, has emerged as a potential adjunct to RSI protocols in select emergency scenarios. Its use may provide a balance between patient comfort, safety, and procedural efficacy (3). Sedatives such as midazolam, fentanyl, and ketamine are frequently employed for conscious sedation due to their rapid onset and favorable pharmacological profiles (4,5).

Recent studies have highlighted that using conscious sedation prior to or during RSI may reduce complications such as hypotension and hypoxia, enhance patient cooperation, and improve first-pass intubation success (6,7). Despite these potential benefits, there remains a lack of consensus regarding its routine implementation in emergency settings, primarily due to variability in patient presentations, provider preferences, and institutional protocols.

Given these uncertainties, there is a need to explore real-world outcomes associated with conscious sedation in RSI. This retrospective study aims to assess the clinical impact of conscious sedation on intubation success, complication rates, and procedural efficiency among patients undergoing emergency RSI.

Study Design and Setting:
This retrospective observational study was conducted in the Emergency Department of a tertiary care hospital. Medical records were reviewed to identify patients who underwent Rapid Sequence Intubation (RSI). Institutional Ethics Committee approval was obtained prior to data collection.

Study Population:
The study included adult patients (aged ≥18 years) who required emergency RSI due to respiratory failure, altered mental status, or airway protection concerns. Patients were excluded if they had incomplete records, were intubated prior to ED arrival, or required crash intubation without medication.

Grouping and Sedation Protocol:
Based on the sedative approach, patients were divided into two groups:

• Group A (Conscious Sedation Group): Received moderate sedation using agents such as midazolam (0.05–0.1 mg/kg), fentanyl (1–2 mcg/kg), or ketamine (0.5 mg/kg), allowing for verbal responsiveness or purposeful movement prior to paralytic administration.
• Group B (Standard RSI Group): Received deep sedation with agents like etomidate (0.3 mg/kg) or higher doses of ketamine (1–2 mg/kg) followed immediately by a neuromuscular blocker (succinylcholine 1.5 mg/kg or rocuronium 1 mg/kg).

Data Collection:
Demographic data (age, gender), clinical diagnosis, vital parameters before and after intubation (heart rate, blood pressure, oxygen saturation), intubation characteristics (time to intubation, number of attempts, success on first attempt), and procedure-related complications (hypotension, desaturation, bradycardia) were recorded using a standardized data abstraction form.

Outcome Measures:
The primary outcome was the success rate of first-pass intubation. Secondary outcomes included hemodynamic changes post-intubation, incidence of adverse events, and total time taken for successful intubation.

Statistical Analysis:
Data were analyzed using SPSS version 26.0. Categorical variables were expressed as frequencies and percentages, while continuous variables were reported as mean ± standard deviation. The Chi-square test was used to compare proportions, and the independent t-test was applied for comparing means. A p-value less than 0.05 was considered statistically significant.

A total of 240 patients who underwent Rapid Sequence Intubation (RSI) in the emergency department were included in the study. Among them, 120 patients received conscious sedation prior to RSI (Group A), and the remaining 120 underwent standard deep sedation protocols (Group B). The baseline demographic and clinical characteristics of the patients are presented in Table 1.

Table 1: Baseline Characteristics of Study Population

No significant difference was observed in age, gender distribution, or baseline vital signs between the two groups (Table 1).

Intubation Success and Timing

Group A demonstrated a higher first-pass success rate (94.2%) compared to Group B (88.3%), which was statistically significant (p=0.043). The mean time to successful intubation was significantly shorter in the conscious sedation group (43.7 ± 8.6 seconds) than in the standard RSI group (47.9 ± 10.1 seconds, p=0.022). These data are detailed in Table 2.

Table 2: Intubation Outcomes

Complication Rates

The incidence of post-intubation hypotension was significantly lower in Group A (12.5%) compared to Group B (21.7%) (p=0.031). Episodes of oxygen desaturation (<90%) occurred in 9.2% of patients in Group A and 11.7% in Group B, which was not statistically significant (p=0.41). Bradycardia was rare in both groups and showed no significant difference. Detailed complication data are shown in Table 3.

Table 3: Complications Following Intubation

In summary, patients receiving conscious sedation had better first-pass success and shorter intubation time, with a lower incidence of post-procedural hypotension when compared to those undergoing standard RSI protocols (Tables 2 and 3).

This retrospective analysis highlights the potential benefits of using conscious sedation in Rapid Sequence Intubation (RSI) for emergency cases, particularly in improving first-pass success rates and minimizing hemodynamic instability. Our findings revealed that patients who received conscious sedation prior to RSI had significantly higher first-pass intubation success and reduced rates of post-intubation hypotension compared to those who underwent conventional RSI with deep sedation. These results align with emerging literature that supports a more tailored approach to airway management in the emergency department (ED) setting.

The observed improvement in first-pass success with conscious sedation may be attributed to the preserved level of consciousness and better neuromuscular coordination during the initial phase of intubation, allowing for easier laryngoscopy and tube placement (1,2). Prior studies have emphasized that multiple intubation attempts are associated with increased complications, including hypoxia, aspiration, and airway trauma (3,4). Therefore, strategies that enhance first-pass success are of paramount importance in the ED.

The hemodynamic stability observed in the conscious sedation group is consistent with previous investigations demonstrating the relatively favorable cardiovascular profile of moderate doses of sedatives such as midazolam, fentanyl, and low-dose ketamine (5–7). Deep sedation combined with neuromuscular blockade, particularly in critically ill patients, often leads to significant drops in blood pressure due to vasodilation and reduced sympathetic tone (8,9). In our study, the incidence of hypotension was nearly halved in the conscious sedation group, underscoring its potential utility in hemodynamically vulnerable patients.

Although oxygen desaturation and bradycardia were slightly less common in the conscious sedation group, these differences were not statistically significant. Similar trends have been noted in other emergency airway studies, where sedation depth plays a role in suppressing protective airway reflexes and respiratory drive (10,11). Conscious sedation may help preserve spontaneous respiration and airway tone, which is advantageous in patients at risk of rapid desaturation, such as those with pulmonary edema or obesity (12,13).

The choice of sedative agents is critical. Ketamine, used in both conscious and deep sedation protocols in this study, is unique in its ability to maintain airway reflexes and support cardiovascular function, making it particularly useful in emergency airway management (14). Midazolam and fentanyl, when used cautiously, provide adequate anxiolysis and analgesia with minimal adverse respiratory effects, supporting their role in conscious sedation strategies (15).

Our study contributes to the growing body of evidence supporting individualized RSI protocols based on patient physiology and clinical context. While the traditional "one-size-fits-all" approach to RSI emphasizes deep sedation and rapid paralysis, this model may not be appropriate for all patients, especially those with borderline hemodynamic parameters or anticipated difficult airways (5,10). Conscious sedation offers a flexible and potentially safer alternative in select cases.

However, the findings must be interpreted in light of certain limitations. The retrospective design is subject to inherent biases, including incomplete documentation and selection bias. Additionally, provider variability in sedation technique and intubation skill could influence outcomes. Future prospective randomized controlled trials are warranted to validate these findings and establish standardized protocols for the use of conscious sedation in RSI.

In conclusion, conscious sedation appears to be a viable and effective adjunct in RSI for emergency patients, particularly when rapid intubation is required but deep sedation may pose hemodynamic risks. This approach can improve procedural success and minimize complications, thereby enhancing the safety of airway management in emergency settings.

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