Esketamine Improved Induction Hemodynamics in Elderly Surgery

Key Takeaways

• Among elderly patients undergoing elective surgery with tracheal intubation general anesthesia, esketamine during induction was associated with higher mean arterial pressure across post-induction and post-intubation measurements than saline.
• Early snuffbox radial artery resistance index values were significantly higher with esketamine at 1 and 5 minutes after induction, while measurements during and after intubation were similar between groups.
• Hypotension, muscle tremor, and vasoactive drug use were less frequent during induction in the esketamine group, with statistically significant between-group differences.
• Recovery time and Steward recovery scores were similar between groups, while postoperative visual analogue scale pain scores were slightly lower with esketamine.

Older adults are especially vulnerable to abrupt blood pressure decline during anesthesia induction because age-related autonomic and vascular changes can narrow hemodynamic reserve in this setting. Maintaining peripheral vascular resistance may therefore be important during the transition from induction to tracheal intubation under general anesthesia, when even brief circulatory instability can be clinically consequential. Whether low-dose esketamine added to a standard induction regimen can blunt that early loss of vascular tone remains an open question, and the snuffbox radial artery resistance index (SBRI) offers a noninvasive marker for tracking that response. That peri-induction vulnerability prompted evaluation of esketamine in elderly patients undergoing elective surgery.

At the General Hospital of the Central Theater Command of the People’s Liberation Army of China, the Li et al randomized trial of esketamine and peri-induction vascular resistance in elderly patients was a single-center, double-blind, prospective, randomized controlled trial. Eighty patients with American Society of Anesthesiologists (ASA) class I to III and New York Heart Association (NYHA) class I status were randomized by random number table, 40 per group, to esketamine 0.3 mg/kg or equal-volume normal saline during induction, and both groups also received etomidate, sufentanil, and rocuronium. Drug administration and outcome assessment were masked. The source reports six exclusions for ultrasound measurement position deviation, leaving 35 patients in the esketamine group and 39 in the control group for the final analysis, although it elsewhere states that intention-to-treat analysis included all randomized patients. Mean arterial pressure (MAP), heart rate (HR), and SBRI were recorded at T1 before induction, T2 1 minute after induction, T3 5 minutes after induction, T4 during intubation, and T5 through T7 at 1, 5, and 10 minutes after intubation, alongside routine non-invasive blood pressure (NIBP) and pulse oxygen saturation (SpO2) monitoring.

MAP was significantly higher with esketamine than control from T2 through T7, with all between-group comparisons P<0.05. The SBRI pattern was concentrated in the early induction window, with significant between-group differences at T2 and T3 but not during intubation or later post-intubation measurements. The source reports significantly higher SBRI with esketamine at T2 and T3, and also reports an adjusted beta-regression estimate 0.972 units higher in the esketamine group (95% CI, 0.747 to 1.197; pseudo R2=0.256); however, elsewhere in the paper a linear model found no significant overall main effect of group on SBRI. HR also differed at some intubation-related time points, with higher mean values in the esketamine group.

During induction, hypotension occurred in 14.3% versus 56.4%, muscle tremor in 8.6% versus 33.3%, and vasoactive drug use in 5.7% versus 38.5%, all favoring esketamine. Hypertension, tachycardia, bradycardia, and coughing did not differ significantly between groups. Recovery time, Steward recovery score, and postoperative adverse reactions were similar between groups, while visual analogue scale (VAS) pain scores were slightly lower with esketamine and remained below 3 points in both groups.

The authors described the trial as single-center with a limited sample size and potential selection bias, and follow-up was confined to peri-induction measurements through 10 minutes after intubation plus immediate postoperative recovery outcomes. Because severe cardiovascular disease and other higher-risk conditions were excluded, the findings mainly reflect relatively healthy elderly patients undergoing elective surgery. The authors also used SBRI as a noninvasive indicator of peripheral vascular resistance rather than a hard clinical outcome, and the between-group separation in that marker was concentrated in the early induction phase.

According to the authors, esketamine during induction was associated with higher peri-induction MAP, an early increase in SBRI, and lower rates of hypotension, muscle tremor, and vasoactive drug use without an apparent recovery penalty in this trial. They also noted that these findings come from a small single-center randomized study and should not be generalized beyond the measured peri-induction and immediate postoperative window.

Clinician Questions

What dose of esketamine was studied during anesthesia induction in elderly surgical patients?

Investigators studied intravenous esketamine 0.3 mg/kg given within 1 minute after the start of induction in elderly elective-surgery patients undergoing tracheal intubation general anesthesia, compared with equal-volume normal saline, with both groups also receiving etomidate, sufentanil, and rocuronium.

How did esketamine affect MAP during anesthesia induction in elderly patients?

MAP was significantly higher in the esketamine group than in the control group from 1 minute after induction through 10 minutes after intubation, corresponding to time points T2 through T7, while baseline MAP did not differ between groups.

Was the SBRI benefit with esketamine sustained after intubation?

SBRI was significantly higher with esketamine at 1 and 5 minutes after induction, corresponding to T2 and T3, but no significant between-group differences were reported during intubation or at 1, 5, and 10 minutes after intubation, corresponding to T4 through T7.

Did esketamine change induction adverse events or recovery outcomes in elderly patients?

Hypotension, muscle tremor, and vasoactive drug use were less frequent with esketamine during induction, whereas hypertension, tachycardia, bradycardia, and coughing were not significantly different. Recovery time, Steward recovery score, and postoperative adverse reactions were similar between groups, while postoperative VAS pain scores were slightly lower with esketamine and remained below 3 points in both groups.

Recommended Reading

• For more on postoperative pain control: The Expanding Role of Peripheral Nerve Stimulation in Acute Pain Control
• For more on anesthesia safety in the OR: Navigating the Crisis: How to Diagnose and Treat Malignant Hyperthermia