S-ketamine anaesthesia improves recovery following modified radical mastectomy

A prospective randomized controlled trial of breast cancer (BC) patients undergoing modified radical mastectomy (MRM) finds that S-ketamine used in place of sufentanil for general anaesthesia (GA) improves postoperative recovery.

“Postoperative cognitive dysfunction, characterized by impairments in memory, attention, consciousness, and sleep cycle, is a common complication associated with GA, which impacts the quality of perioperative rehabilitation and may affect the long-term prognosis of patients with BC,” wrote the researchers. [Exp Gerontol 2020;doi:10.1016/j.exger.2019.110791; World J Surg 2019;43:1949-1956]

S-ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, is a novel antidepressant drug shown to have neuroprotective properties as well as the ability to stabilize perioperative haemodynamic fluctuations, and relieve perioperative stress and inflammatory response. [Am J Transl Res 2021;13:1701-1709] As a result, it is widely used as an adjunct to GA for optimal pain management and accelerated emotional recovery, although investigations into its use as part of GA are relatively recent. [Eur J Anaesthesiol 2020;37:394-401; J Clin Pharm Ther 2022;47:759-766] “The present trial explored the effects of GA with S-ketamine on quality of recovery and cognitive function in BC patients following MRM,” stated the researchers.

Trial participants (n=86; age, 45–75 years) were randomly allocated 1:1 to the S-ketamine or control group. Patients in the S-ketamine group received 0.5 mg/kg S-ketamine instead of sufentanil for induction and were maintained with remifentanil and S-ketamine. In the control group, patients were induced with sufentanil and maintained with remifentanil. [BMC Anesthesiol 2023;doi:10.1186/s12871-023-02161-6]

Since the first 48 hours after surgery are pivotal for patients’ recovery, global Quality of Recovery-15 (QoR-15) and Mini-Mental State Examination (MMSE) scores on postoperative day 1 (POD1) and postoperative day 2 (POD2) were chosen as primary outcomes.

Global QoR-15 scores on POD1 were significantly higher in the S-ketamine vs control group (median, 124 vs 119; p=0.002), which remained the case on POD2 (median, 140 vs 132; p=0.004) “Among the five subdimensions of the QoR-15 scale, scores for pain, physical comfort, and emotional state on POD1 and POD2 were significantly higher in the S-ketamine group [p<0.05], which indicated that S-ketamine can effectively control patients’ postoperative pain, relieve negative emotions, and improve physical comfort,” added the researchers. However, scores for physical independence and psychological support were comparable between the two groups on both days.

MMSE scores, which were used to determine patients’ cognitive status, showed no significant difference at baseline or on POD2 between the two groups. However, on POD1, MMSE scores were significantly higher in the S-ketamine vs control group (p<0.05), demonstrating that S-ketamine–based GA was more likely to facilitate cognitive function rehabilitation of BC patients in the early postoperative period.

Postoperative pain intensity was also assessed in the study. While visual analogue scale scores were similar between the two groups immediately at the end of surgery and 48 hours after surgery, they were significantly lower in the S-ketamine vs control group at 4 hours, 6 hours and 24 hours post-surgery. “Notably, use of remedial analgesia within 48 hours post-surgery was significantly lower in the S-ketamine vs control group [5.0 percent vs 22.5 percent; p<0.05],” highlighted the researchers.

The incidence of postoperative nausea and vomiting was significantly lower in the S-ketamine vs control group (7.5 percent vs 27.5 percent; p=0.019). Furthermore, anaesthesia satisfaction score was significantly higher in the S-ketamine vs control group (9 vs 8; p<0.001).

No significant differences were observed in duration of postoperative care unit stay, dizziness or agitation between the two groups. None of the patients exhibited any of the psychotomimetic adverse reactions associated with S-ketamine, such as hallucinations or nightmares.

“Collectively, our findings demonstrate that GA with S-ketamine improves postoperative recovery [mainly through improving physical comfort, pain, and emotional state] and promotes cognitive function recovery on POD1 following MRM, without increasing the rate of adverse reactions,” summarized the researchers.