The Effect of Different Doses of Ketamine on Postoperative Hallucination: A Cross-Sectional Study

Postoperative hallucinations and other psychotropic effects are known side effects of ketamine that may be dose-dependent. In a study of 62 people (32 males, 30 females) aged 16–60 undergoing various surgeries under general anesthesia, different doses of ketamine (30, 40, 50, and 100 mg/kg) and durations of administration (10–20, 21–30, 31–40, and more than 40 minutes) were evaluated. Hallucination types (visual, auditory, or both) and severity scores (mild, moderate, severe) were monitored. Results showed significant differences between doses and durations with hallucination types and scores. The incidence and severity of postoperative hallucinations are closely tied to the dose: low doses are related to reduced risk, while moderate and high doses significantly increase risk.

Study at a glance

Abstract

Postoperative hallucinations and other psychotropic effects are known side effects, which may be dose-dependent. Higher doses exacerbate these changes, prolonging dissociative and hallucinatory experiences postoperatively. The study aimed to evaluate the effect of ketamine different doses on postoperative hallucination (score and types). This study was applied on (62) persons including (32) males and (30) females under general anesthesia (G.A). The patients' ages range between (16-60) years for both those who have various surgeries under general anesthesia also all the patients submitted to the study questionnaire for assessing the effects of various ketamine doses on postoperative hallucinations. Different doses of ketamine were induced, including (30, 40, 50 and 100) mg/kg and different durations of ketamine administration (10-20), (21-30), (31-40) and more than (40 minutes) with observing and monitoring the hallucination types (visual, auditory and visual/auditory) as well as its score (mild, moderate and severe). In the induction stage; propofol administrated at a (1-3) mg/kg dose. In the premedication stage; midazolam was induced at a (0.3-0.03) mg/kg dose. In the maintenance stage; isoflurane and sevoflurane were induced at a dose of (0.5-3) %. The muscle relaxants; atracurium (0.1 mg/kg) and rocuronium (0.5 mg/kg) were induced. Mechanical ventilation and non-invasive monitoring of blood pressure and pulse oximetry were also monitored. At the end of the operation, a muscle relaxant reflector was induced with the combination of neostigmine (0.05 mg/kg) and atropine (0.02 mg/kg). A suction apparatus was also used in the recovery stage. The results showed significant differences between the different doses of ketamine with hallucination types and hallucination score, as well as there are statistically significant differences between the different time durations of ketamine administration with hallucination types and hallucination score at (p-value <0.0001). The study concludes that the incidence and severity of postoperative hallucination are closely tied to the dose of ketamine administration. Ketamine with low dose is related to a reduced risk of hallucinations, while the moderate and highly are doses significantly increase risk. Clinicians must carefully consider the dose of ketamine used in perioperative settings, taking into account patient-specific factors and implementing strategies to minimize adverse psychological effects.