The rapid emergence and recovery from general anesthesia afforded by sevoflurane is associated with a high incidence of emergence agitation in children. Small doses of ketamine reduce the incidence of emergence agitation. This study compared the effects of ketamine 0.25 mg/kg and 0.5 mg/kg on emergence agitation and postoperative pain. The effects of added intravenous ketamine were evaluated in 93 children, ASA I-II, 2-14 years old, undergoing an adenotonsillectomy. The patients were allocated randomly to one of three groups receiving saline (group C), ketamine 0.25 mg/kg (group K0.25) or ketamine 0.5 mg/kg (group K0.5). The children in each group were administered the study drugs 10 minutes before the end of surgery. The recovery characteristics, including the time to extubation, delivery time from the PACU, postoperative nausea and vomiting, agitation and pain were assessed. There were no significant differences in the extubation time, delivery time and postoperative nausea and vomiting between the three groups. There were significant differences in modified CHEOPS (Children's Hospital of Eastern Ontario Pain Scale) between the three groups. The incidence of emergence agitation was low in the K0.25 and K0.5 groups compared to the control group. However, there was no significant difference between the K0.25 and K0.5 groups. There was no significant difference in the incidence of emergence agitation between K0.25 and K0.5 groups. However, K0.5 group showed a lower pain score than K0.25 group.

Cha MH, et al. Yonsei Med J. 2012 Mar;53(2):427-432. http://dx.doi.org/10.3349/ymj.2012.53.2.427

Emergence agitation (EA) frequently occurs after desflurane anesthesia in children. Ketamine, because of its sedative and analgesic properties, might be useful for the management of separation anxiety and EA. We investigated the preventive effect of ketamine on separation anxiety and EA after desflurane anesthesia in children for brief ophthalmic surgery. Sixty children, ranging in age from 2-8 years old, undergoing brief ophthalmic surgery were randomly allocated to one of the 3 groups: group C received normal saline, group K1.0 received ketamine 1.0 mg/kg intravenously before entering the operating room, or group K0.5 received ketamine 0.5 mg/kg 10 min before the end of the surgery. Before induction, the separation anxiety score was evaluated. Extubation time, post-anesthesia care unit stay time, postoperative nausea and vomiting, emergence agitation, and pain were assessed. The group K1.0 had a lower separation anxiety score compared with groups K0.5 and C. Extubation time in group K0.5 was significantly prolonged compared with groups K1.0 and C. The incidence of EA and the modified Children's Hospital of Eastern Ontario Pain Scale were significantly lower in group K1.0 and group K0.5 compared to group C, but there was no significant difference between groups K1.0 and K0.5. In children undergoing brief ophthalmic surgery with desflurane anesthesia, ketamine 1.0 mg/kg administered before entering the operating room reduced separation anxiety, postoperative pain, and incidence of EA without delay in recovery.

Min TJ, et al. J Korean Med Sci. 2011 Jun;26(6):747-752. http://dx.doi.org/10.3346/jkms.2011.26.6.747

We investigated the haemodynamic and respiratory effects of propofol target-controlled infusion (TCI) during spontaneous ventilation. We studied 20 patients scheduled for elective orthopaedic surgery who were classified as American Society of Anesthesiologists physical status I. During spontaneous ventilation, haemodynamic, respiratory and electroencephalographic variables were measured. Oxygen flow was maintained at 5 1/min using a semi-closed system and a close-fitting face mask. All measurements were obtained before the propofol TCI and at each propofol effect-site concentration (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 μg/ml). Changes in Bispectral Index Score, systolic blood pressure, diastolic blood pressure, end tidal carbon dioxide tension and heart rate were negatively correlated with propofol effect-site concentrations. Despite maintaining oxygen saturation (> 99%), apnoea and blood pressure reductions were abruptly induced as the propofol effect-site concentration increased. We therefore recommend careful monitoring of haemodynamic and respiratory function during spontaneous ventilation using propofol TCI.

There are various reports on the effects of the anesthetic method on neurologic complications. A population-based study was conducted to estimate the effect of anesthetic method on the incidence of postoperative delirium in patients that underwent total hip replacement arthroplasty in South Korea. The Korean National Health Insurance claims database was used to retrospectively identify and analyze 24,379 cases of total hip replacement arthroplasty, defined as patients having a claim record with the operation code 'N0711,' from January 2008 to December 2017. Patients were divided into two groups, a general anesthesia group (n = 9,921) and a regional anesthesia group (n = 14,458). The incidence of delirium was assessed in cases when patients used medications for delirium, such as haloperidol, chlorpromazine, olanzapine, and risperidone. Of the 9,921 patients receiving general anesthesia and 14,458 receiving regional anesthesia, 142 (1.43%) and 209 (0.86%) experienced postoperative delirium after total hip replacement arthroplasty, respectively. There was no significant difference between the groups (P = 0.92). In logistic regression analysis, sex (P = 0.038) and patients with acquired immune deficiency syndrome (P = 0.008) were predictors of postoperative delirium. Our results revealed that the anesthetic method was not associated with the incidence of postoperative delirium. In addition, the results suggest that male patients and patients with acquired immune deficiency syndrome undergoing total hip replacement arthroplasty carefully managed for postoperative delirium after surgery.