Observer's Assessment of Alertness/Sedation-based titration reduces propofol consumption and incidence of hypotension during general anesthesia induction: A randomized controlled trial

Abstract

Administration of a single propofol bolus dose for anesthesia induction causes hypotension. We included 160 patients (74 males and 86 females; mean age, 42.4 ± 10.7 [range: 18-60] years) with the American Society of Anesthesiologists status I-II undergoing elective surgery under general anesthesia. Using simple randomization, the patients were divided into a conventional group (n = 80; received 2 mg/kg propofol at a rate of 250 mg/min) and titrated group (n = 80; received propofol at a rate of 1 mg/kg/min until the Observer's Assessment of Alertness/Sedation scale score reached 1 point). Fentanyl (4 µg/kg) and cisatracurium (0.2 mg/kg) were administered, as appropriate. Systolic blood pressure, diastolic blood pressure, mean blood pressure, and heart rate were recorded at different time points. Propofol consumption, hypotension, and other adverse events were recorded. All the patients were intubated without awareness. Compared with the conventional group, the titrated group showed more stable blood pressure (p < 0.05), as well as a lower decrease in systolic blood pressure, mean blood pressure at 1 and 3 min, and diastolic blood pressure at 1 min after propofol administration (p < 0.01). Moreover, compared with the conventional group, the titrated group showed a lower post-intubation hypotension incidence (9 vs. 19 cases; p = 0.04), as well as lower total propofol dosage and propofol dose per kilogram of body weight (93.57 ± 14.40 mg vs. 116.80 ± 22.37 mg and 1.73 ± 0.27 mg/kg vs. 2.02 ± 0.08 mg/kg, respectively, p < 0.01). Compared with conventional propofol usage, titrated propofol administration can reduce the incidence of hypotension and propofol consumption during anesthesia induction.

Keywords: Propofol; administration and dosage; general anesthesia; hypotension; individuation; rapid sequence induction and intubation.

Conflict of interest statement

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.

CONSORT diagram of the study. Group C: conventional group, propofol was conventionally administered as a single bolus dose calculated based on the body weight. Group T: titrated group, propofol was administered at a rate of 1 mg/kg/min until the OAA/S score reached 1 point. OAA/S: Observer’s Assessment of Alertness/Sedation.

Figure 2.

Changing trend of SBP, DBP, MAP, and HR before and after intubation. (a) Changing trend of SBP before intubation. (b) Changing trend of DBP before intubation. (c) Changing trend of MAP before intubation. (d) Changing trend of HR before intubation. (e) Changing trend of SBP after endotracheal intubation. (f) Changing trend of DBP after endotracheal intubation. (g) Changing trend of MAP after endotracheal intubation. (h) Changing trend of HR after endotracheal intubation. Group T and Group C: as shown in Figure 1. T0: baseline before propofol administration; T1, T2, and T3: 1 min, 3 min, and 5 min, respectively, after propofol administration; T4: immediately after endotracheal intubation; T5, T6, and T7: 1 min, 3 min, and 5 min, respectively, after endotracheal intubation. ANOVA for repeated measures. ＃p < 0.05 between two groups, *p < 0.01 is compared with the conventional group.

Figure 3.

Propofol consumption during induction before intubation and when intubation completed. Data are presented as mean ± SD. Group T and Group C: as shown in Figure 1. (a) Total propofol consumption before intubation. (b) Propofol consumption per kilogram of body weight before intubation. (c) Total propofol consumption at the completion of intubation. (d) Propofol consumption per kilogram of body weight at the completion of intubation. Student's t-test, *p < 0.01 is compared with the titrated group.

Figure 4.

Scattered profile of propofol consumption per kilogram of body weight before tracheal intubation in the titrated group. (a) Scattered plot of the frequency distribution of propofol dosage per kilogram of body weight. (b) Case distribution at different dose ranges per kilogram of body weight.