Antiemetic effect of propofol administered at the end of surgery in laparoscopic assisted vaginal hysterectomy / 대한마취과학회지

BACKGROUND: Postoperative nausea and vomiting (PONV) commonly occur after general anesthesia, especially in women. In this study, we evaluated the antiemetic efficacy of propofol administered at the end of surgery in highly susceptible patients undergoing a laparoscopy-assisted vaginal hysterectomy. METHODS: A total of 107 women undergoing a laparoscopy-assisted vaginal hysterectomy under general anesthesia were enrolled for this prospective, double-blind, randomized study. Fifteen minutes before the end of surgery, all patients received 50 microg fentanyl and 1 of following 3 doses; 0.5 mg/kg of propofol (propofol 0.5 group), 1 mg/kg of propofol (propofol 1.0 group), and normal saline (control group). All patients received intravenous patient-controlled analgesia (PCA). Emergence time, a visual analog scale for pain and nausea, duration of postanesthesia care unit (PACU) stay, and frequency of antiemetic use were recorded at 0-2, 2-24, and 24-48 hours postoperatively. RESULTS: The incidence of nausea significantly lower in the propofol 0.5 and propofol 1.0 groups than in the control group (12.1 vs 14.7 vs 40%). During the first postoperative 2 hours, antiemetics were less frequently administered in the propofol 0.5 and propofol 1.0 groups than in the control group (3.0 vs 5.9 vs 22.5%). Emergence time was slightly longer in the propofol 0.5 and propofol 1.0 groups than in the control group, but there was no significant difference in PACU stay time was observed between the 3 groups. CONCLUSIONS: The results of this study suggest that low-dose propofol administration at the end of surgery may effectively reduce the incidence of PONV within 2 hours postoperatively in highly susceptible women undergoing a laparoscopiy-assisted vaginal hysterectomy and receiving opioid-based PCA.

EC50 and EC95 of remifentanil to prevent rocuronium-induced withdrawal movements in children / 대한마취과학회지

BACKGROUND: Intravenous administration of rocuronium induces intense pain in most patients (60-100%). This could be harmful during anesthesia induction because of the unintended reflex movement of an unconscious patient in response to the pain. Previous studies have reported that remifentanil effectively reduces rocuronium-induced pain and withdrawal movements. This study was designed to evaluate the EC50 and EC95 of remifentanil to prevent withdrawal movements in children. METHODS: We enrolled a total of 171 pediatric patients scheduled for general anesthesia in this study. Remifentanil was administrated by target-controlled infusion. Effect-site target concentrations ranged from 0.5 to 3.0 ng/ml. At each concentration, experiments were repeated in 10-20 patients. Propofol 2 mg/kg and rocuronium 0.9 mg/kg were administrated after equilibration of plasma and effect-site target remifentanil concentration. The withdrawal movements were graded on a 4-point scale. The EC50 and EC95 of remifentanil to prevent rocuronium-induced withdrawal movements were determined by using a logistic regression model. RESULTS: The logistic regression model showed that the probability of preventing rocuronium-induced withdrawal movement was as follows: exp (-3.49 + 2.07 x remifentanil concentration) / (1 + exp [-3.49 + 2.07 x remifentanil concentration]). EC50 and EC95 were 1.69 ng/ml (95% confidence intervals [CIs], 1.42-1.87) and 3.11 ng/ml (95% CIs, 2.79-3.72), respectively. CONCLUSIONS: Administration of remifentanil at an effect-site target concentration of 3.1 ng/ml could effectively prevent rocuronium-induced withdrawal movements.

Comparison of ramosetron's and ondansetron's preventive anti-emetic effects in highly susceptible patients undergoing abdominal hysterectomy / 대한마취과학회지

BACKGROUND: This study compared the preventive effects of ramosetron and ondansetron on postoperative nausea and vomiting (PONV) in highly susceptible patients undergoing abdominal hysterectomy. METHODS: In a prospective, randomized, double-blinded study, a total of 120 highly susceptible women (nonsmokers, those receiving opioid-based IV patient-controlled analgesia [PCA]) undergoing abdominal hysterectomy were included in the study. Patients were divided into 2 groups and each group received either 0.3 mg of ramosetron or 4 mg of ondansetron, IV. All patients received fentanyl-based IV PCA during the 48 h postoperative periods. The incidences of PONV and side effects of 5-HT3 antagonists (headache and dizziness) were assessed at 3 intervals (<2 h, 2-24 h and 24-48 h) postoperatively. RESULTS: Patients in the ramosetron group showed a significantly higher ratio of complete response and lower incidence of nausea during the 24-48 h interval after surgery compared with those the ondansetron group. CONCLUSIONS: Ramosetron (0.3 mg) is more effective in preventing delayed PONV in highly susceptible women undergoing abdominal hysterectomy compared with ondansetron (4 mg).

Wrapping of the lower limbs for prevention of post spinal hypotension during cesarean section under spinal anesthesia

BACKGROUND: Hypotension is the most frequent complication associated with spinal anesthesia during cesarean section. Prehydration and/or vasopressor therapy is commonly used for prevention of hypotension in cesarean deliveries. Wrapping of the legs is simple to perform before surgery and was reported be effective for the prevention of post spinal hypotension in a few obstetric units. So we investigated whether wrapping of the legs prevents post spinal hypotension during cesarean section. METHODS: 45 patients were randomly allocated to one of 3 groups (15 in each group): prehydration with 10 ml/kg (group I), prehydration with 10 ml/kg and wrapping of the legs (group II), prehydration with 5 ml/kg and wrapping of the legs (group III). Hypotension was defined as a 20% decrease from initial systolic arterial pressure (SAP) or SAP lower than 90 mmHg and was treated with intravenous ephedrine (4 mg, repeated). Blood pressure was recorded before spinal anesthesia and every min for 10 min and then every 2 min for another 10 min after spinal anesthesia. RESULTS: Group I showed a significant decrease in SAP compared to group II and group III 1 min after spinal anesthesia, but after that, there was no significant difference between the three groups. Group II showed a significant difference in incidence of severe hypotension after spinal anesthesia compared with group I, but there was no difference of the incidence of hypotension between the three groups. CONCLUSIONS: Wrapping of the legs for prevention of post spinal hypotension during elective cesarean section reduces the severity of hypotension.

Effects of preoxygenation with the three minutes tidal volume breathing technique in the elderly / 대한마취과학회지

BACKGROUND: Preoxygenation with tidal volume breathing for 3 min is commonly used technique. An end tidal expiratory oxygen concentration greater than 90% is considerd to be adequate for preoxygenation. The aim of this study was to check the effects of preoxygenation on elderly patients through the comparison with young patients during the 3 min tidal volume breathing technique. METHODS: Sixty patients from ASA class I or II who were scheduled for elective orthopedic general surgery were divided into an elderly (>65 yr) group and a control (25-65 yr) group. Patients were instructed in the technique of preoxygenation. Preoxygenation was accomplished with an appropriately sized face mask connected to an anesthesia machine with 100% oxygen during 3 min with patients in both groups. Expired O2, CO2 concentration and oxygen saturation were recorded simultaneously for 3 min. RESULTS: The elderly group showed significantly lower end tidal oxygen concentration than the control group from 50 sec to the end of study (180 sec) with the 3 min tidal volume breathing technique (P < 0.05). In 180 sec, the control group had over 90% (91.5%) end tidal oxygen concentration, but in the elderly group end tidal oxygen concentration could not reach 90% (86.2%). In oxygen saturation, the elderly group showed a significantly lower level until 40 sec from the start of study, and then two groups showed a similar levels of oxygen saturation until the end of study. CONCLUSIONS: End tidal oxygen concentration did not reach 90% in 180 sec in the elderly group during preoxygenation with the 3 min tidal volume breathing technique.

Comparison of alfentanil and remifentanil for the use of patient controlled sedation under local anesthesia during ear, nose and throat surgery / 대한마취과학회지

BACKGROUND: This study was conducted to compare the effects of alfentanil and remifentanil on patient controlled sedation (PCS). METHODS: 60 patients scheduled for ear, nose and throat surgery under local anesthesia were randomly allocated to Group P (n = 20, propofol 10 mg/ml), Group A (n = 20, propofol 10 mg/ml with alfentanil 500 microg/ml) and Group R (n = 20, propofol 10 mg/ml with remifentanil 10 microg/ml). Without a basal rate, bolus was set to 2 ml with one minute of lockout time. RESULTS: A total of 57 patients were included in this study. Group A was found to have a lower blood pressure and pulse rate than group R. Group R showed a lower PCS dose upto an OAA/S (Observer's Assessment of Alertness/Sedation Scale) value of 4 and a higher OAA/S prior to surgery than group P. Group P was found to have a higher blood pressure and respiration rate than Group A. During PCS, patient anxiety was significantly decreased in all groups. In addition, there was no differences among groups in the level of pain during the perioperative period, delivery/attempt ratio, satisfaction of the patient and surgeon, and number of patients required to undergo the same PCS technique again. The frequency of side effects of PCS, which included pain on injection, transient hypertension, hypotension, desaturation and oversedation, were similar among groups. CONCLUSIONS: Evaluation of patients who underwent ear, nose and throat surgery under local anesthesia using PCS with propofol alone or alfentanil or remifentanil revealed no differences in safety, effectiveness, complications or satisfaction of the patients and surgeons.

The changes of the sternomental distance under general anesthesia and with increasing age

BACKGROUND: Because the sternomental distance (SMD) is evaluated in conscience patients and in the sitting position, this could change under general anesthesia, which is a state that the patient is unconscious and fully relaxed in the supine position. Increasing age also affects the SMD. We investigated the change in the SMD with the patients under general anesthesia and we also investigated the effect of age on the SMD. METHODS: A total of 108 patients were allocated to Group Y (20-30 yr), Group M (31-50 yr) and Group O (51-70 yr). The SMD, as measured when the patients were awake and sitting, was defined as baseline. The SMD was measured in the supine position, the shoulder-suppressed supine position, at the time of loss of consciousness (LOC), 4 min after vecuronium administration and in the sniffing position. The percent change of the SMD (%) was defined as (the baseline SMD - the measured SMD)/the baseline SMD x 100. RESULTS: Compared with the baseline, the SMD decreased significantly in the supine position, the shoulder-suppressed supine position, at the time of LOC, during neuromuscular blockade and in the sniffing position in all the groups. Group O showed a shorter SMD than did Groups Y and M for all the measurements. There was no significant difference in the percent change of the SMD between the groups. CONCLUSIONS: This study demonstrated that the SMD was significantly reduced by the supine position, the sniffing position, at the time of loss of consciousness and during neuromuscular blockade with the patient under general anesthesia and also with the increasing age of the patient.

The optimal preemptive dose of gabapentin following gynecologic surgery / 대한마취과학회지

BACKGROUND: Gabapentin decreases acute nociceptive pain in animal and human studies when given before surgical incision. Various doses of gabapentin have been used (300-1,200 mg) to measure this preemptive effect. Here, we evaluated the optimal dose of gabapentin for reducing fentanyl consumption and the adverse effects of gabapentin following gynecologic surgery. METHODS: We recruited 100 patients who underwent laparotomy for gynecologic surgery. Patients were randomly divided into 4 groups and received a placebo (control), gabapentin 300 mg (G 300), gabapentin 600 mg (G 600), or gabapentin 1,200 mg (G 1200) 2 h before surgery. Postoperatively, patients received fentanyl via an intravenous patient controlled analgesia device. The cumulative fentanyl doses were recorded 2, 6, 12, 24 h, and 48 h postoperatively, and the sedation scale was recorded in the post anesthetic care unit (PACU). RESULTS: The postoperative fentanyl requirement was lower with gabapentin treatment, but there was no significant differences for the different doses. PACU sedation scores were not different in any group. CONCLUSIONS: Gabapentin has a preemptive effect in gynecologic surgery, but there were no additional fentanyl-sparing benefits at doses above 300 mg. Thus, 300 mg is an optimal dose for decreasing fentanyl consumption following gynecologic surgery.