Gabapentin and Pressor Response to Intubation

Laryngoscopic tracheal intubation often triggers a significant sympathetic response, causing increased heart rate, blood pressure, and other hemodynamic changes, which can pose risks for patients with underlying cardiovascular or cerebrovascular conditions. While various methods and drugs have been employed to mitigate this pressor response, gabapentin-a GABA analog with multimodal effects-has shown promise in reducing such hemodynamic stress. This study aims to evaluate the effectiveness of oral gabapentin as a pretreatment to attenuate the sympathetic response during intubation.

The objective of this study is to compare the effectiveness of gabapentin versus placebo in reducing stress responses, such as mean arterial pressure (MAP), heart rate (HR), and blood pressure (BP), during general anesthesia with endotracheal intubation.

Study Design is Prospective, double-blind, randomized controlled trial and will be conducted in Department of Anesthesia, Liaquat National Hospital.

during 8 months. 144 patients (72 per group), calculated based on prior MAP data, with patients randomized into Gabapentin (Group G) and Placebo (Group P) Patients aged 18-59 years, ASA I or II, undergoing elective surgeries will be included.

Exclusion criteria

is difficult intubation, ASA III or higher, obesity, or use of antihypertensive or sedative drugs.

Participants will receive either 300 mg oral gabapentin or placebo 2 hours before surgery. Standard monitoring and anesthesia protocols will be followed, with blood pressure and heart rate recorded at baseline, 2 minutes, and 5 minutes post-intubation. The primary outcome is MAP, while secondary outcomes include systolic/diastolic BP and HR. Intravenous metoprolol will be administered if required for pressor responses.

SPSS v25 will be used for statistical analysis, with independent t-tests for quantitative data and chi-square tests for categorical variables. A p-value <0.05 will be considered statistically significant.

Hypothesis:

Null: Gabapentin does not attenuate the pressor response. Alternative: Gabapentin attenuates the pressor response.

Rationale:

Gabapentin's potential to modulate sympathetic responses during intubation offers a novel, multimodal approach to anesthesia management. While international studies exist, no local studies have been conducted, making this research vital for assessing its efficacy in the local population.

Inclusion criteria

• ASA I or II patients (American Society of Anesthesiologists Physical Status Classification).
• Age between 18 and 59 years.
• Scheduled for elective surgery under general anesthesia with endotracheal intubation.

Exclusion criteria

• Anticipated difficult intubation.
• ASA III or greater.
• Patients with hiatus hernia or gastro-esophageal reflux disease (GERD).
• Body weight more than 20% of ideal body weight.
• Patients on antihypertensive drugs, sedatives, hypnotics, or antidepressants.