# Effects of different doses of alfentanil on tracheal intubation stress responses in ambulatory hysteroscopic surgery: a randomized, double-blind, clinical comparative study

## TL;DR

This study compares different doses of alfentanil to see how well they reduce stress and pain during hysteroscopic surgery, finding that 30 μg/kg is most effective.

## Contribution

The study introduces evidence that 30 μg/kg alfentanil is optimal for minimizing stress and pain during ambulatory hysteroscopic surgery.

## Key findings

- 30 μg/kg and 40 μg/kg alfentanil reduced stress and pain compared to lower doses and fentanyl.
- 40 μg/kg alfentanil increased hypotension and bradycardia risks.
- 30 μg/kg alfentanil showed better hemodynamic stability and pain control.

## Abstract

This randomized, double-blind, clinical comparative study aims to compare the tracheal intubation stress responses of different doses of alfentanil in anesthesia induction for ambulatory hysteroscopic surgery, as well as their impact on the quality of early postoperative recovery.

This study enrolled a total of 160 patients aged 20–60 years scheduled for ambulatory hysteroscopic surgery. All patients underwent tracheal intubation under general anesthesia and were randomly allocated into four groups using a random number table. The low-dose alfentanil group (group AL) patients received an induction dose of 20 μg/kg alfentanil, the medium-dose alfentanil group (group AM) patients received 30 μg/kg alfentanil, the high-dose alfentanil group (group AH) received 40 μg/kg alfentanil, and the Fentanyl Group (group F) patients received an induction dose of 4 μg/kg fentanyl, with all groups additionally administered midazolam, cisatracurium, and propofol as part of the standardized induction protocol. Anesthesia maintenance was maintained with propofol and remifentanil in all groups. The primary outcome measure was the plasma norepinephrine (NE) level at 1 min after tracheal intubation (T2). Secondary outcomes included plasma NE and epinephrine (E) levels at baseline (T0, before anesthesia induction), T2 (excluding NE as it was the primary measure), and 5 min post-intubation (T3), along with mean arterial pressure (MAP) and heart rate (HR) at T0, the time of the insertion of the tracheal tube (T1), T2, T3, 5 min after the removal of the tracheal tube (T4); additionally, extubation time, awakening time, post-anesthesia care unit (PACU) stay duration, Steward score and numerical rating scale (NRS) pain score during the PACU stay were evaluated. Safety endpoints comprised the incidence of hypertension, hypotension, tachycardia, and bradycardia from anesthesia induction to 5 min after tracheal intubation, as well as adverse events such as nausea, vomiting, and agitation during the emergence period.

The levels of plasma NE and E in group AL were significantly higher than that in group F at T2, the levels of plasma NE and E in group AM were significantly lower than that in group AL at T2 ~ T3, and the levels of plasma NE and E in group AH were significantly lower than that in group AL and group F at T2 ~ T3 (p < 0.05). Compared with group F, MAP and HR in group AL were significantly higher at T2 (p < 0.05). Compared with group AL, MAP and HR in group AM were significantly lower at T1 ~ T3 (p < 0.05), the incidence of hypertension and tachycardia from anesthesia induction to 5 min after tracheal intubation was significantly lower in group AM (p < 0.05). Compared with group AL and group F, MAP and HR in group AH were significantly lower at T1 ~ T3 (p < 0.05), the incidence of hypotension and bradycardia was significantly higher from anesthesia induction to 5 min after tracheal intubation, and the incidence of hypertension and tachycardia was significantly lower (p < 0.05). The NRS pain scores at the time of extubation in group AL were significantly higher than in groups AM, AH, and F (p < 0.05).

In ambulatory hysteroscopic surgery, intravenous 30 μg/kg and 40 μg/kg alfentanil inhibited the stress reaction caused by tracheal intubation, alleviated hemodynamic fluctuations, and decreased the intensity of postoperative pain. However, 40 μg/kg alfentanil significantly increased the incidence of hypotension and bradycardia from anesthesia induction to 5 min after tracheal intubation. Therefore, 30 μg/kg alfentanil may be more suitable for the application of ambulatory hysteroscopic surgery.

https://www.chictr.org.cn, ChiCTR2300073590.