Physiological and Behavioral Pain Responses to Endotracheal Suctioning in Unconscious ICU Patients: An Observational Study

Objective: This study aimed to evaluate the effect of endotracheal suctioning on physiological and behavioral pain responses in unconscious patients admitted to intensive care units.

Methods: A descriptive observational study was conducted from September 26, 2024, to May 12, 2025, in the ICUs of Imam Al-Hussein Medical City and Imam Al-Hassan Al-Mujtaba Teaching Hospital in Kerbala, Iraq. A purposive sample of 80 unconscious intubated patients was observed. Physiological parameters (SBP, DBP, MAP, HR, RR, SpO₂) and behavioral responses (using the Behavioral Pain Scale) were recorded at three intervals: before, during, and five minutes after endotracheal suctioning. Data were analyzed using SPSS v26, applying descriptive and inferential statistics, including repeated-measures ANOVA and chi-square tests.

Findings: Endotracheal suctioning resulted in significant increases in systolic and diastolic blood pressure, heart rate, respiratory rate, and behavioral pain scores, accompanied by a significant decrease in oxygen saturation (p < 0.001). Behavioral responses, such as grimacing (55%), limb retraction (40%), and ventilator fighting (23.8%), increased during the procedure. All parameters returned to near-baseline post-procedure. Significant associations were found between pain responses and ICU admission causes, duration of unconsciousness, and sex for specific parameters (e.g., SpO₂, HR).

Conclusion: Endotracheal suctioning acts as a potent noxious stimulus, eliciting pronounced physiological and behavioral pain responses in unconscious patients. Routine assessment using validated behavioral tools is crucial for pain management in non-communicative ICU patients.