Sex differences in serious outcomes among critically ill adults following endotracheal intubation

Abstract

BACKGROUND

Several studies have reported sex differences in resuscitation outcomes in critically ill adults, but whether these differences are associated with endotracheal intubation practices is not known.

AIM

To investigate sex differences in serious outcomes among critically ill adults undergoing endotracheal intubation in the emergency department.

METHODS

In this observational study, we enrolled all critically ill adult patients who underwent endotracheal intubation in the emergency department from 2016 to 2020. The serious outcomes were defined as mortality within 1 hour post endotracheal intubation, cardiac arrest within 1 hour post intubation, worsening hypotension (systolic blood pressure < 90 mmHg) and oxygen desaturation (< 92%). Variables known or suspected to be associated with serious outcomes were examined with univariate logistic regression. Furthermore, we conducted sensitivity analysis on the patient cohort, incorporating propensity score matching with nearest neighbor methods at a ratio of 1:1 to address baseline variations between male and female participants, using R program software version 4.1.3 with a library (MatchIT).

RESULTS

A total of 1021 patients were enrolled in our study, with a median age of 52.2 years (± 17.5). The mean age of the females was 52.2 (± 17.8) years, and that of the males was 52.1 (± 17.3) years. Endotracheal intubation was most frequently observed in males (634; 62%). The frequency of cardiac arrest was 118 (18.6%) males and 77 (19.9%) females, with a P value of 0.612. Similarly, the frequency of hypotension (systolic blood pressure < 90 mmHg) was 225 (35.5%) in males and 154 (39.8%) in females (P = 0.167). This was followed by hypoxia (< 92%), with 85 (13.4%) males and 46 (11.9%) females, with a P value of 0.481. In total, 263 (41.5%) males died in the hospital, whereas 135 (39.1%) females died, P = 0.036. Severe outcomes were observed in 702 (68.8%) patients, 271 (70%) of whom were females, whereas 431 (68%) of whom were men (P = 0.494). After propensity score matching, postintubation hypotension was the most frequent serious event, observed in 304 (39.3%) patients, of whom 154 (39.8%) were females, whereas 150 (39.8%) were males (P = 0.001).

CONCLUSION

The study revealed that females were at greater risk of serious outcomes in critically ill adults post endotracheal intubation than males were in the emergency department.

Key Words: Sex; Serious outcomes; Emergency medicine; Airway; Predictors; Endotracheal intubation

Core Tip: This study explores sex-based differences in outcomes following endotracheal intubation in critically ill adults in the emergency department. Although overall complication rates were comparable between men and women, females demonstrated a higher incidence of post-intubation hypotension, even after adjustment for baseline clinical factors. This suggests that sex-related physiological differences may influence hemodynamic responses during airway management. The findings underscore the importance of recognizing sex as a potential risk modifier and highlight the need for tailored, sex-specific strategies to improve safety and optimize outcomes in critically ill patients undergoing intubation.

INTRODUCTION

Sex differences in resuscitation outcomes are the subject of research in different specialties[1-4]. Endotracheal intubation is a high-risk procedure that is associated with complications[5]. The few cases that are commonly reported in the emergency medicine and critical care literature are hypotension, cardiac arrest, oxygen desaturation and mortality[6,7]. Although studies report variations in outcomes based on gender, the results are not always consistent across different settings and populations. Data from developing countries concerning the frequency and characteristics of intubation in the emergency department are scarce. There is only one study from Pakistan that reports a high proportion of males (65%) intubated in emergencies, but predictors of serious outcomes are lacking[8].

Previous studies have shown that a high proportion of males receive endotracheal intubation in the emergency department[9-11]. The reason may be the severity of the disease, certain clinical or laboratory predictors and limited access to care, which allows patients to present late in the healthcare facility. Several other factors may also contribute to these differences, such as sociodemographic and cultural characteristics, physiological variability, disease severity at presentation, and differences in management strategies across genders. Furthermore, the decision to perform endotracheal intubation among critically ill adults presenting with critical illness with underlying physiological instability is highly challenging. Sex differences, with several inherent biological and nonbiological factors, can influence sex-related outcomes but are rarely investigated and require further exploration.

Among the strategies proposed to reduce morbidity and mortality associated with endotracheal intubation, the sex-related significance of its predictors is still a matter of debate. Research in this area is anticipated to better understand these differences and develop strategies to better care and improve outcomes for all critically ill adults requiring endotracheal intubation. Therefore, the aim of this study was to investigate sex differences in serious outcomes among critically ill adults in the emergency department.

MATERIALS AND METHODS

Study design

This hospital-based observational study was conducted in the Emergency Department of Aga Khan University Hospital, Pakistan, from January 01, 2016 to December 31, 2020. The Ethical Review Committee of our hospital approved this study (approval No. 2020-4975-14778).

Setting and subjects

The Aga Khan University Hospital is an urban academic teaching hospital located in the city of Karachi, Pakistan. The city has a population of over 20 million. Our emergency department has over 62 beds and treats over 60000 patients annually. All critically ill adult patients aged at least 18 years and above who required endotracheal intubation in the emergency department were included. We excluded patients who experienced out-of-hospital cardiac arrest, patients with oropharyngeal tumors with deformed airway anatomy, and pregnant women due to anatomical and physiological challenges.

Data collection

The International Classification of Diseases-10 was used to retrieve data from electronic health records. The International Classification of Diseases-10 is a medical classification system predominantly developed by the World Health Organization to classify health issues according to illness categories. The data were obtained via paper questionnaires that were piloted on 10 samples prior to the commencement of the formal data collection. The pilot samples were excluded from the final analysis. Preliminary data were examined for completeness and omissions. Research associates were trained to gather data on airway management variables. Paper questionnaires with a unique identifier were used to collect the data to minimize potential identifiers. Every day, an emergency physician evaluated the completed questionnaires for inconsistencies and missing data. The study questionnaire collected data on demographics, symptoms and signs, preintubation arterial blood gases, presentation, postintubation vital signs, the shock index and disposition details. HEAVEN criteria variables were gathered to predict difficult airways in the emergency department. The data were entered into Aga Khan University’s REDCap electronic data capture tool, a secure web-based software platform designed to facilitate the collection of data for research investigations[12].

Outcomes

The study outcome was considered a serious outcome and included cardiac arrest (defined as the absence of a pulse during or after endotracheal intubation), immediate postintubation mortality (defined as death occurring within 1 hour of the emergency), hypotension (defined as a reduction in systolic blood < 90 mmHg postintubation) and postintubation hypoxia (noninvasive oxygen saturation < 92%). Post-intubation hypotension was defined as the lowest recorded systolic blood pressure (< 90 mmHg) within 30 minutes following endotracheal intubation. This time-based criterion aligns with previously published work on peri-intubation haemodynamic instability and allows for consistent capture of early post-procedural hypotension. Post-intubation hypoxaemia was defined as oxygen desaturation (< 92%) within 30 minutes post-intubation. Where available, inspired oxygen and arterial blood gas values were used to confirm desaturation events.

Statistical analysis

The statistical analysis was performed via version 22.0 of IBM SPSS for Windows. Descriptive analysis was performed on the entire dataset via the mean ± SD, median (interquartile range) and n (%), as appropriate. The associations between outcomes (hypotension, hypoxia, mortality and cardiac arrest) and demographic, clinical and laboratory characteristics were evaluated via the χ² test/Fisher’s exact test or independent sample t-test/Mann-Whitney U test, as appropriate. Continuous variables such as age (years), number of endotracheal intubations, systolic and diastolic blood pressures (mmHg), heart rate (beats/minutes), pH, oxygen saturation (%) and the shock index were dichotomized. The χ² test or Fisher’s exact test was used to compare groups of binary data to test for trends in males and females. The associations between sex and serious outcomes were explored via binary logistic regression models. Variables known or suspected to be associated with serious outcomes were examined with univariate logistic regression. Sensitivity analysis was performed through propensity score matching via nearest neighbor methods at a ratio of 1:1 to address baseline variations between male and female participants via R program software version 4.1.3 via a library (MatchIt). To ensure balance between the two genders, we match several covariates, including age, shifts, preintubation triage vital variables (systolic and diastolic blood pressure, temperature, heart rate, respiratory rate, and oxygen saturation), coma, hypoxia, metabolic acidosis, anticipated decline, respiratory distress, polytrauma, isolated trauma, gunshot injury, the shock index and predictors of difficulty. We used a 1:1 matching ratio with a caliper of 0.02 to successfully pair 774 participants (387 in each group), as shown in Supplementary Table 1. The results are presented as odds ratios with 95% confidence intervals. P = 0.05 was considered statistically significant in all analyses.

RESULTS

Patient characteristics

A total of 1021 patients were enrolled in this study, with a mean age of 52.2 (± 17.5) years. Males and females were similar in terms of mean age, time of intubation, preintubation blood pressure and oxygen saturation. The two groups differed in terms of the reason for intubation, shock index, preintubation pH and presence of difficult intubation factors, such as anatomical abnormalities and vomiting/fluid (Table 1).

Table 1 Emergency department intubation characteristics between males and females, n (%)/median (interquartile range).

Characteristics	Total 1021	Sex distribution		OR (95%CI)	P value
		Female 387	Male 634
Age (years), mean ± SD	52.2 ± 17.5	52.2 ± 17.8	52.1 ± 17.3		0.986
Age groups
< 45 years	336 (32.9)	126 (32.6)	210 (33.1)	1.026 (0.784-1.343)	0.852
≥ 45 years	685 (67.1)	261 (67.4)	424 (66.9)
Shifts
Night (10 PM-08 AM)	427 (41.8)	181 (46.8)	246 (38.8)	0.722 (0.559-0.943)	0.012
Morning to evening (08 AM-10 PM)	594 (58.2)	206 (53.2)	388 (61.2)
Pre intubation vitals
Systolic blood pressure (mmHg)	130 (153-110)	128 (150-110)	130 (155-110)		0.311
Diastolic blood pressure (mmHg)	77 (90-62)	75 (89-60)	78 (90-63)		0.133
Heart rate	106 (122-88)	108 (126-90)	106 (120-86)		0.260
Oxygen saturations (%)	94 (98-81)	95 (98-81)	94 (98-80)		0.614
Respiratory rate	25 (32-20)	25 (32-20)	25 (32-20)		0.692
Reasons for intubation
Coma	39 (3.8)	12 (3.1)	27 (4.3)	0.719 (0.360-1.437)	0.349
Hypoxia	119 (11.7)	47 (12.1)	72 (11.4)	1.075 (0.727-1.590)	0.703
Metabolic acidosis	136 (13.3)	52 (13.4)	84 (13.2)	1.016 (0.701-1.474)	0.932
Anticipated decline	147 (14.4)	55 (14.2)	92 (14.5)	0.979 (0.682-1.404)	0.895
Respiratory distress	395 (38.8)	171 (44.2)	224 (35.4)	1.442 (1.114-1.867)	0.005
Polytrauma	24 (2.4)	4 (1)	20 (3.2)	0.320 (0.109-0.944)	0.03
Isolated trauma (trauma to one body region, not gunshot wound)	32 (3.1)	5 (1.3)	27 (4.3)	0.294 (0.112-0.771)	0.008
Gunshot injury	10 (1)	3 (0.8)	7 (1.1)	0.700 (0.180-2.722)	0.605
Others	29 (2.8)	11 (2.8)	18 (2.8)	1.004 (0.469-2.149)	0.998
Shock index
< 0.9	587 (57.5)	196 (50.6)	391 (61.7)	1.568 (1.214-2.025)	< 0.001
≥ 0.9	434 (42.5)	191 (49.4)	243 (38.3)
pH
≥ 7.3	444 (43.5)	220 (32.8)	224 (63.8)	1.298 (1.004-1.677)	< 0.001
< 7.3	577 (56.5)	450 (67.2)	127 (36.2)
HEAVEN criteria
Hypoxemia	414 (40.5)	158 (40.8)	256 (40.4)	1.019 (0.788-1.318)	0.887
Extremes of size	22 (2.2)	8 (2.1)	14 (2.2)	0.935 (0.389-2.249)	0.880
Anatomic abnormalities	35 (3.4)	0 (0)	35 (5.5)	0.095 (0.023-0.397)	< 0.001
Aspiration (vomit/blood/fluid)	219 (21.4)	119 (30.7)	100 (15.8)	2.371 (1.750-3.212)	< 0.001
Exsanguination	60 (5.9)	14 (3.6)	46 (7.3)	0.480 (0.260-0.885)	0.016
Neck mobility issues	17 (1.7)	7 (1.8)	10 (1.6)	1.149 (0.434-3.045)	0.779

OR: Odds ratio; CI: Confidence interval; AM: Ante meridiem; PM: Post meridiem.

Outcome analysis

Severe outcomes were observed in 702 (68.8%) patients (Table 2). Among patients who underwent endotracheal intubation, 379 (37.1%) experienced severe postintubation events. It was observed less frequently among males (225, 35.5%) than among females (154, 39.8%), but the difference was not statistically significant (odds ratio: 1.201, P = 0.167). Similarly, no sex-based differences were observed in the frequency of cardiac arrest or desaturation (< 92%).

Table 2 Sex differences in outcome of patients requiring endotracheal intubation, n (%).

Characteristics	Total 1021	Sex distribution		OR (95%CI)	P value
		Female 387	Male 634
Cardiac arrest	195 (19.1)	77 (19.9)	118 (18.6)	1.086 (0.789-1.496)	0.612
Post intubation hypotension (SBP < 100 mmHg)	379 (37.1)	154 (39.8)	225 (35.5)	1.201 (0.925-1.559)	0.167
Desaturation (< 92%)	131 (12.8)	46 (11.9)	85 (13.4)	0.871 (0.594-1.278)	0.481
Death in emergency (within 1 hour after intubation)	7 (0.7)	3 (0.8)	4 (0.6)	1.232 (0.274-5.533)	0.786
Death in hospital	398 (39.1)	135 (35)	263 (41.5)	0.756 (0.682-0.982)	0.036
Discharge	492 (48.3)	198 (51.3)	294 (46.4)	1.21 (0.941-1.561)	0.137
Serious outcomes	702 (68.8)	271 (70)	431 (68)	1.10 (0.837-1.447)	0.494

OR: Odds ratio; CI: Confidence interval; SBP: Systolic blood pressure.

Logistic regression analysis

The sex-based predictors of serious outcomes in males and females were assessed first through univariate analysis and then through multivariate analysis. In the logistic regression analysis for the prediction of serious outcomes in males, age > 45 years [1.8 (1.15-2.8)], morning-evening shift duty [1.52 (1.12-2.33)], drowsiness [1.72 (1.05-2.81)], vomiting [1.65 (1.07-2.56)], hypoxia [3.96 (1.97-7.92)], anticipated decline [2.05 (1.05-3.99)], shock index > 0.9 [2.81 (1.74-4.55)] and pH < 7.3 [2.55 (1.65-3.93)] were found to be significant (Table 3). Similarly, in the logistic regression analysis for the prediction of serious outcomes in females, hypoxia [3.78 (1.88-7.6)], respiratory distress [2.01 (1.09-3.69)], shock index > 0.9 [2.17 (1.25-3.75)] and pH [2.17 (1.25-3.75)] were found to be significant (Table 4).

Table 3 Univariate and multivariate logistic regression analysis for predicting serious outcomes among males following endotracheal intubation.

Parameters	Univariate		Multivariate-initial level		Multivariate-final level
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
Age ≥ 45 years	2.06 (1.46-2.92)	< 0.001	1.82 (1.14-2.91)	0.012	1.8 (1.15-2.8)	0.009
Shift duty (morning-evening)	1.68 (1.2-2.36)	0.003	1.49 (0.97-2.29)	0.071	1.52 (1.12-2.33)	0.048
Altered mental status	1.07 (0.75-1.52)	0.704
Coma (GCS ≤ 6)	1.26 (0.57-2.81)	0.569
Fever	2.06 (1.29-3.29)	0.003	1.21 (0.68-2.18)	0.515
Drowsiness (< 15)	2.78 (1.86-4.18)	< 0.001	1.74 (1.03-2.94)	0.037	1.72 (1.05-2.81)	0.03
Shortness of breath	1.55 (1.1-2.18)	0.013	1.07 (0.64-1.77)	0.801
Seizures	0.46 (0.25-0.85)	0.014	0.97 (0.43-2.18)	0.941
Vomiting/blood/fluid	1.7 (1.03-2.8)	0.037	1.06 (0.55-2.03)	0.865	1.65 (1.07-2.56)	0.024
Hypoxia	4.35 (2.42-7.81)	< 0.001	3.78 (1.88-7.6)	< 0.001	3.96 (1.97-7.92)	< 0.001
Metabolic acidosis	2.19 (1.24-3.88)	0.007	1.48 (0.74-2.95)	0.268
Anticipated decline	1.97 (1.16-3.37)	0.013	2.09 (1.07-4.08)	0.031	2.05 (1.05-3.99)	0.034
Respiratory distress	1.51 (1.05-2.16)	0.025	1.29 (0.8-2.09)	0.294
Polytrauma	0.7 (0.28-1.73)	0.433
Isolated trauma	0.57 (0.26-1.25)	0.162
Gunshot	0.45 (0.13-1.57)	0.210
Shock index ≥ 0.9	3.18 (2.37-4.27)	< 0.001	2.81 (1.72-4.58)	< 0.001	2.81 (1.74-4.55)	< 0.001
pH group ≤ 7.3	1.92 (1.47-2.509)	< 0.001	2.52 (1.62-3.9)	< 0.001	2.55 (1.65-3.93)	< 0.001

OR: Odds ratio; CI: Confidence interval; GCS: Glasgow Coma Scale.

Table 4 Univariate and multivariate logistic regression analysis for predicting serious outcomes among females following endotracheal intubation.

Parameters	Univariate		Multivariate
	OR (95%CI)	P value	OR (95%CI)	P value
Age ≥ 45 years	1.2 (0.76-1.89)	0.444
Shift duty (morning-evening)	1.33 (0.86-2.05)	0.202
Altered mental status	1.08 (0.7-1.68)	0.726
Coma	0.42 (0.13-1.32)	0.135
Fever	1.37 (0.78-2.39)	0.277
Drowsiness	1.39 (0.88-2.19)	0.155
Shortness of breath	1.55 (1.1-2.18)	0.013	0.73 (0.44-1.21)	0.225
Seizures	0.48 (0.21-1.11)	0.086
Vomiting/blood/fluid	2.38 (1.41-4.03)	0.001
Trauma	1.15 (0.3-4.4)	0.843
Hypoxia	6.63 (2.79-15.75)	< 0.001	3.78 (1.88-7.6)	< 0.001
Metabolic acidosis	1.5 (0.76-2.98)	0.246
Anticipated decline	0.94 (0.51-1.75)	0.845
Respiratory distress	1.99 (1.22-3.23)	0.006	2.01 (1.09-3.69)	0.024
Polytrauma	0.42 (0.06-3.05)	0.394
Isolated trauma	0.64 (0.11-3.87)	0.625
Gun shot injury	0.86 (0.08-9.52)	0.899
Shock index ≥ 0.9	2.97 (1.87-4.71)	< 0.001	3.24 (1.87-5.61)	< 0.001
pH group ≤ 7.3	1.64 (1.05-2.55)	0.029	2.17 (1.25-3.75)	0.006

OR: Odds ratio; CI: Confidence interval.

Potential confounders in the sample were assessed through propensity score matching, and a balance was achieved in the baseline variables for both the treated and control groups. The histograms showing the propensity score matching for both the treated and control groups as identical in Supplementary Figure 1. A total of 774 patients were successfully matched with 387 individuals in both the male and female groups. All covariates, including age, shifts, pre-intubation triage vital variables (systolic and diastolic blood pressure, temperature, heart rate, respiratory rate, and oxygen saturation), coma, hypoxia, metabolic acidosis, anticipated decline as assessed by the physician, respiratory distress, polytrauma, isolated trauma, gunshot injury, shock index and predictors of difficulty, were found to be insignificant (P > 0.05) in both males and females. Adjustment emergency department intubation characteristics between through propensity score matching in Supplementary Table 1.

After the application of propensity score matching, serious outcomes were observed in 532 individuals (68.7%) (Table 5). Postintubation hypotension was the most frequent serious event, occurring in 304 (39.3%) patients, of whom 154 (39.8%) were females and 150 (39.8%) were males. This difference was statistically significant (P = 0.001). Additionally, desaturation was observed in 66 (11.9%) males and 46 (11.9%) females. However, cardiac arrest was observed more frequently in females [77 (19.9%)]. However, no sex difference was observed in terms of death in the emergency department or discharge from the hospital.

Table 5 Adjustment of sex differences in outcome of patients requiring endotracheal intubation through propensity score.

Outcome	Total	Sex distribution		P value
		Male	Female
Total	774	387	387	-
Outcome
Cardiac arrest	147 (19)	70 (18.1)	77 (19.9)	0.009
Hypotension (SBP < 100 mmHg)	304 (39.3)	150 (38.8)	154 (39.8)	< 0.001
Oxygen saturation (> 92%)	92 (11.9)	46 (11.9)	46 (11.9)	0.012
Death in emergency	7 (0.9)	4 (1)	3 (0.8)	0.292
Death in hospital	271 (35)	136 (35.1)	135 (34.9)	< 0.001
Discharge	396 (51.2)	198 (51.2)	198 (51.2)	< 0.001
Serious outcome	532 (68.7)	261 (67.4)	271 (70)	< 0.001

SBP: Systolic blood pressure.

DISCUSSION

This study demonstrated that there is a discernible difference in serious outcomes following endotracheal intubation among critically ill males and females in the emergency department. According to our outcome criteria, the overall percentage of serious outcomes was 702 (68.8%). These outcomes were determined by the presence of any one of the following: Postintubation hypotension, postintubation desaturation, cardiac arrest, or death following intubation. The frequency of serious outcomes was greater in males [431 (68%)] than in females [271 (70%)], possibly because of chance or the number of people who underwent endotracheal intubation in the emergency department. No correlation was found between sex disparities and deaths in the emergency department. We assessed potential confounders between males and females via propensity score matching, after which severe outcomes were observed in 532 participants. The most frequently observed serious event after adjustment for confounders was postintubation hypotension [304 (39.3%)], which was most common in females. This difference was statistically significant and may be due to various physiological differences. Additionally, cardiac arrest was also observed more frequently in females [77 (19.9%)]. We found no sex differences in death in the emergency department or discharge from the hospital.

However, a greater number of males than females underwent intubation. It is unclear from the current research whether this disparity arises either owing to random chance or delayed arrival at the emergency department. Healthcare system-based factors, such as an undeveloped healthcare system and inadequate basic healthcare facilities, can play a role in this difference. In our healthcare system, medical care is carried out mostly by patients, which leads to delays in seeking timely consultation. This may result in deterioration of the patient’s clinical condition and subsequent presentation under serious conditions. Furthermore, as our hospital is a private healthcare setup, most patients are either referred or shifted from other hospitals in critical condition, which results in an increased proportion of P1- and P2-category triage patients in emergencies. Our study revealed sex differences in the frequency of serious outcomes, with females having poor outcomes compared with males. We believe that several biological and nonbiological factors could influence sex-related outcomes. It is possible that females are at greater risk for negative effects or that men are seen as less robust. Physiological, biological, and social distinctions, among other factors, may play a significant role in explaining this phenomenon[8]. Severe outcomes in critical patients with endotracheal intubation are more common in males than in females[5,6], which contrasts with our study, but the frequency of intubation was greater in males in our study, which may support this notion. In females, hypoxia, respiratory distress, a shock index > 0.9 and a pH < 7.3 were the most common serious outcomes. These findings were similar in males except for those aged > 45 years, vomiting, anticipated decline and drowsiness. Our study results emphasize that it is necessary to pay attention to physiological derangements in both males and females. Timely interventions for these critical presentations may prevent serious outcomes. Also, incomplete inspired oxygen and arterial blood gas data may have led to measurement bias regarding the criteria for hypoxaemia (oxygen desaturation < 92%). Pulse oximetry may have been less accurate because of poor peripheral perfusion or interference from nail polish, which is more common in women[13,14]. Future studies are needed to determine causality in discrepancies between genders in addition to investigating differences in clinical presentations in other areas of Pakistan. The results derived from the city of Karachi may not reflect the trends and practices observed in other cities. By identifying differences in presentations and outcomes, medical education and training can be curtailed accordingly to provide more effective care in emergency medicine education. The demographics of our study are highly consistent with those of studies from North America, the United Kingdom and European critical care and emergency department airway registries[9-11,15]. Our study also revealed that many of the intubations were performed in the early morning to evening, which is in accordance with the previously published literature[9,11].

Our study has several limitations. First, the study is retrospective and represents data from a single center, which limits its ability to be represented from other emergency departments. Despite significant correction for baseline factors, clinical presentation and postintubation parameters using propensity scores, bias and lack of data should be considered. The macro- and micro physiological parameters, as well as those of the medicines employed during intubation, may have benefited from sensitivity analysis and modification. This study exhibits numerous deficiencies. The retrospective design may result in unmeasured confounding variables. Important facts, such as how severe the sickness was, what drugs were given during intubation, and how the procedure went, were not always written down in the records. To fix the initial imbalance, propensity score matching was used. However, there may still be some residual confusion. This study was conducted at a single tertiary care centre, which may limit the applicability of the results to other emergency contexts. Excluding cases of cardiac arrest outside of the hospital may have reduced the frequency of certain serious incidents. When figuring out how generalisable our findings are, these things should be kept in mind.

However, only accessible and known covariables were adjusted. Comorbidities, the severity of disease presentation and the effects of medications on patient vital signs were not recorded in our investigation. Owing to the frequent occurrence of severe outcomes, caution is crucial when interpreting the results of our sex stratification models. However, we anticipate such limitations and purposefully plan an exploratory study. Since our hospital is a tertiary, academic, private health care center, our emergency department may exaggerate the genuine rate of severely unwell patients.

CONCLUSION

Our research revealed differences in the frequency of serious outcomes after endotracheal intubation in the emergency department between males and females. There is a need for multicenter studies for external validation of our findings and to explore factors related to serious outcomes among critically ill patients.