Dosing study of esmolol for reducing hemodynamic changes during lightwand intubation

Abstract

Background: Lightwand is a convenient tool that can be used instead of a laryngoscope for intubation. Tracheal intubation causes direct stimulation of the larynx, drastically increasing hemodynamic values including blood pressure and heart rate. This study aims to identify the effect of different doses of esmolol on hemodynamic changes during lightwand intubation.

Methods: The study subjects included 140 patients who underwent general anesthesia for elective surgery. The patients were randomly divided into four groups (35 patients in each group). The 'C' group only received 20 ml of normal saline, while the 'E0.5', 'E1', and 'E2' groups received 20 ml of normal saline containing esmolol-0.5 mg/kg, 1 mg/kg, and 2 mg/kg, respectively, injected 2 min prior to intubation. The patients' blood pressure, heart rate, and rate-pressure product were measured six times, before and after the intubation.

Results: The degree of heart rate elevation was suppressed in the E1 and E2 groups compared to the C group, and RPP after intubation significantly decreased in the E2 group compared to the C group.

Conclusions: Esmolol injection, 1-2 mg/kg, prior to lightwand intubation effectively blunts heart rate elevation, and 2 mg/kg of esmolol injection blunts rate-pressure product elevation.

Keywords: Blood pressure; Esmolol; Heart rate; Intubation; Lightwand; Rate pressure product.

Fig. 1.

Flowchart illustrating the selection of patients. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg.

Fig. 2.

SBP changes with lightwand intubation in the four patient groups. All values are expressed as mean values. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg, SBP: systolic blood pressure, T_B: before induction (baseline), T_I: 2 min before intubation (induction), T₁: 1 min after intubation, T₃: 3 min after intubation, T₅: 5 min after intubation, T₁₀: 10 min after intubation.

Fig. 3.

DBP changes with lightwand intubation in the four patient groups. All values are expressed as mean values. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg, DBP: diastolic blood pressure, T_B: before induction (baseline), T_I: 2 min before intubation (induction), T₁: 1 min after intubation, T₃: 3 min after intubation, T₅: 5 min after intubation, T₁0: 10 min after intubation.

Fig. 4.

MBP changes with lightwand intubation in the four patient groups. All values are expressed as mean values. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg, MBP: mean blood pressure, T_B: before induction (baseline), T_I: 2 min before intubation (induction), T₁: 1 min after intubation, T₃: 3 min after intubation, T₅: 5 min after intubation, T₁0: 10 min after intubation.

Fig. 5.

HR changes with lightwand intubation in the four patient groups. Comparison of measurements in C group and E1 group showed significant differences in HR at 1 min after intubation (T₁) (100.11 vs. 85.34, P ≤ 0.001), as well as at 3 min after intubation (T₃) (93.94 vs. 83.63, P = 0.02). Similarly, comparison of measurements in C group and E2 group demonstrated significant differences in HR at 1 min after intubation (T₁) (100.11 vs. 87.09, P ≤ 0.001), as well as at 3 min after intubation (T₃) (93.94 vs. 81.97, P ≤ 0.001). All values are expressed as mean values. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg, HR: heart rate, T_B: before induction (baseline), T_I: 2 min before intubation (induction), T₁: 1 min after intubation, T₃: 3 min after intubation, T₅: 5 min after intubation, T₁₀: 10 min after intubation. *P < 0.05 compared with C group.

Fig. 6.

RPP changes with lightwand intubation in the four patient groups. Comparison of RPP measurements in C group and E2 group showed significant differences at 1 min after intubation (T₁) (15,003.43 vs. 11,665.40, P = 0.001) and 3 min after intubation (T₃) (12,162.37 vs. 9,861.89, P = 0.002). All values are expressed as mean values. C: control, E0.5: esmolol 0.5 mg/kg, E1: esmolol 1.0 mg/kg, E2: esmolol 2.0 mg/kg, RPP: rate-pressure product, T_B: before induction (baseline), T_I: 2 min before intubation (induction), T₁: 1 min after intubation, T₃: 3 min after intubation, T₅: 5 min after intubation, T₁₀: 10 min after intubation. *P < 0.05 compared with C group.