A randomised controlled trial of intracuff lidocaine and alkalised lidocaine for sedation and analgesia requirements in mechanically ventilated patients.

Background: Airway irritation caused by prolonged inflation of endotracheal tube (ETT) cuff results in post-intubation morbidities.

Objectives: We aimed to study intracuff lidocaine and alkalised lidocaine on sedation or analgesia requirements of patients undergoing mechanical ventilation in the intensive care unit (ICU). The primary outcome was to calculate the total dose of propofol and fentanyl required to obtund the unwanted airway and circulatory reflexes. Secondary outcomes were to determine the frequency and severity of cough and haemodynamic parameters.

Methods: It was a double-blinded, randomised controlled study in the ICU after emergency laparotomy, in patients aged 20 - 55 years, and classified as American Society of Anesthesiologists (ASA) classes 1E and 2E with tube in situ. Exclusion criteria were patients with body mass index >30 kg/m² , haemodynamic instability, requiring positive end-expiratory pressure ≥7 cm H₂O, and a history of chronic obstructive pulmonary disease. After ethics clearance and written consent, patients were randomly assigned into two groups (36 in each), Group L (ETT cuff inflated with lidocaine 2%) and Group AL (cuff inflated with a mixture of lidocaine 2% and sodium bicarbonate 1:1).

Results: Mean dose of propofol consumed in Group AL was significantly less than that in Group L (p<0.001). The mean standard deviation (SD) fentanyl utilisation in Group AL was 1 323.61 (187.27) µg, and that in Group L was 1433.09 (42.58) µg (p=0.040). Group L patients had a significantly higher incidence of cough than those in Group AL (p=0.01). There was no significant difference in the mean arterial pressure (p=0.22), although heart rate was significantly higher in Group L (p<0.001).

Conclusion: Alkalised lidocaine reduces the requirement of sedation, analgesia, and the incidence of cough in intubated patients maintaining haemodynamic stability when compared with lidocaine.

Contributions of the study: Alkalised lidocaine when used in endotracheal tube cuff inflation reduces the need for sedation and analgesia in mechanically-ventilated patients, and improves haemodynamic stability.