Background: This study investigated the relationship between intraoperative requirement for an inhalational anesthetic (sevoflurane) or an opioid (remifentanil) and postoperative analgesic consumption. Methods: The study included 200 adult patients undergoing elective laparoscopic colectomy. In the sevoflurane group, the effect-site concentration of remifentanil was fixed at 1.0 ng/ml, while the inspiratory sevoflurane concentration was adjusted to maintain an appropriate anesthetic depth. In the remifentanil group, the end-expiratory sevoflurane concentration was fixed at 1.0 volume%, and the remifentanil concentration was adjusted. Pain scores and cumulative postoperative analgesic consumptions were evaluated at 2, 6, 24, and 48 h after surgery. Results: Average end-tidal concentration of sevoflurane and effect-site concentration of remifentanil were 2.0 ± 0.4 volume% and 3.9 ± 1.4 ng/ml in the sevoflurane and remifentanil groups, respectively. Cumulative postoperative analgesic consumption at 48 h postoperatively was 55 ± 26 ml in the sevoflurane group and 57 ± 33 ml in the remifentanil group. In the remifentanil group, the postoperative cumulative analgesic consumptions at 2 and 6 h were positively correlated with intraoperative remifentanil requirements (2 h: r = 0.36, P < 0.01; 6 h: r = 0.38, P < 0.01). However, there was no significant correlation in the sevoflurane group (r = 0.04, P = 0.69). Conclusions The amount of intraoperative requirement of short acting opioid, remifentanil, is correlated with postoperative analgesic consumption within postoperative 6 h. It may be contributed by the development of acute opioid tolerance. However, intraoperative sevoflurane requirement had no effect on postoperative analgesic consumption.

Background: This study aimed to evaluate the effects of hypercarbia on arterial oxygenation during one-lung ventilation (OLV). Methods: Fifty adult patients undergoing elective video-assisted thoracoscopic lobectomy or pneumonectomy were enrolled. Group I patients (n = 25) were first maintained at normocarbia (PaCO2: 38‒42 mmHg) for 30 min and then at hypercarbia (45‒50 mmHg). In Group II patients (n = 25), PaCO2 was maintained in the reverse order. Arterial oxygen partial pressure (PaO2), respiratory variables, hemodynamic variables, and hemoglobin concentration were compared during normocarbia and hypercarbia. Arterial O2 content and O2 delivery were calculated. Results: PaO2 values during normocarbia and hypercarbia were 66.5 ± 10.6 and 79.7 ± 17.3 mmHg, respectively (mean difference: 13.2 mmHg, 95% CI for difference of means: 17.0 to 9.3, P < 0.001). SaO2 values during normocarbia and hypercarbia were 92.5 ± 4.8% and 94.3 ± 3.1% (P = 0.009), respectively. Static compliance of the lung (33.0 ± 5.4 vs. 30.4 ± 5.3 ml/cmH2O, P < 0.001), arterial O2 content (15.4 ± 1.4 vs. 14.9 ± 1.5 ml/dl, P < 0.001) and O2 delivery (69.9 ± 18.4 vs. 65.1 ± 18.1 ml/min, P < 0.001) were significantly higher during hypercarbia than during normocarbia. Conclusions Hypercarbia increases PaO2 and O2 carrying capacity and improves pulmonary mechanics during OLV, suggesting that it may help manage oxygenation during OLV. Therefore, permissive hypercarbia may be a simple and valuable modality to manage arterial oxygenation during OLV.

Background: This study aimed to evaluate the effects of hypercarbia on arterial oxygenation during one-lung ventilation (OLV). Methods: Fifty adult patients undergoing elective video-assisted thoracoscopic lobectomy or pneumonectomy were enrolled. Group I patients (n = 25) were first maintained at normocarbia (PaCO2: 38‒42 mmHg) for 30 min and then at hypercarbia (45‒50 mmHg). In Group II patients (n = 25), PaCO2 was maintained in the reverse order. Arterial oxygen partial pressure (PaO2), respiratory variables, hemodynamic variables, and hemoglobin concentration were compared during normocarbia and hypercarbia. Arterial O2 content and O2 delivery were calculated. Results: PaO2 values during normocarbia and hypercarbia were 66.5 ± 10.6 and 79.7 ± 17.3 mmHg, respectively (mean difference: 13.2 mmHg, 95% CI for difference of means: 17.0 to 9.3, P < 0.001). SaO2 values during normocarbia and hypercarbia were 92.5 ± 4.8% and 94.3 ± 3.1% (P = 0.009), respectively. Static compliance of the lung (33.0 ± 5.4 vs. 30.4 ± 5.3 ml/cmH2O, P < 0.001), arterial O2 content (15.4 ± 1.4 vs. 14.9 ± 1.5 ml/dl, P < 0.001) and O2 delivery (69.9 ± 18.4 vs. 65.1 ± 18.1 ml/min, P < 0.001) were significantly higher during hypercarbia than during normocarbia. Conclusions Hypercarbia increases PaO2 and O2 carrying capacity and improves pulmonary mechanics during OLV, suggesting that it may help manage oxygenation during OLV. Therefore, permissive hypercarbia may be a simple and valuable modality to manage arterial oxygenation during OLV.

BACKGROUND: The current study evaluated the hemodynamic effects of different types of pneumatic compressions of the lower extremities during anesthesia induction. In addition, the hemodynamic effects were compared between patients older than 65 age years and those aged 65 years or younger. METHODS: One hundred and eighty patients (90: > 65 years and 90: ≤ 65 years) were enrolled. Each age group of patients was randomly assigned to one of three groups; Group 1 (no compression), Group 2 (sequential pneumatic compression), and Group 3 (sustained pneumatic compression without decompression). Invasive blood pressure, cardiac index (CI), and stroke volume variation (SVV) were measured. RESULTS: In patients aged ≤ 65 years, mean arterial pressure (MAP) and CI were significantly higher and SVV was lower in Group 3 compared to Group 1 before tracheal intubation, but there were no differences between Groups 1 and 2. However, there were no differences in MAP, CI, and SVV among the three groups in patients aged > 65 years. The number of patients who showed a MAP < 60 mmHg was less in Group 3 than Group 1 in patients aged ≤ 65 years, but not in patients aged > 65 years. CONCLUSIONS: Sustained pneumatic compression of the lower extremities has more hemodynamic stabilizing effects compared to sequential compression during anesthesia induction in patients aged 65 years or younger. However, no difference between methods of compression was observed in patients older than 65 years.
Anesthesia* ; Arterial Pressure ; Blood Pressure ; Hemodynamics* ; Humans ; Intubation ; Lower Extremity* ; Prospective Studies* ; Stroke Volume

BACKGROUND: We compared the analgesic efficacy and side effects of ketorolac and nefopam that were co-administered with fentanyl via intravenous patient-controlled analgesia. METHODS: One hundred and sixty patients scheduled for laparoscopic cholecystectomy were randomly assigned to ketorolac (Group K) or nefopam (Group N) groups. The anesthetic regimen was standardized for all patients. The analgesic solution contained fentanyl 600 µg and ketorolac 180 mg in Group K, and fentanyl 600 µg and nefopam 120 mg in Group N. The total volume of analgesic solution was 120 ml. Postoperative analgesic consumption, recovery of pulmonary function, and pain intensities at rest and during the forced expiration were evaluated at postoperative 2, 6, 24, and 48 h. The postoperative side effects of analgesics were recorded. RESULTS: Cumulative postoperative analgesic consumptions at postoperative 48 h were comparable (Group K: 93.4 ± 24.0 ml vs. Group N: 92.9 ± 26.1 ml, P = 0.906) between the groups. Pain scores at rest and during deep breathing were similar at the time of each examination. The recovery of pulmonary function showed no significant differences between the groups. Overall, postoperative nausea and vomiting incidence was higher in Group N compared with Group K (59% vs. 34%, P = 0.015). The other side effects were comparable between both groups. CONCLUSIONS: Analgesic efficacies of ketorolac and nefopam that were co-administered with fentanyl for postoperative pain management as adjuvant analgesics were similar. However, postoperative nausea and vomiting incidence was higher in the nefopam-fentanyl combination compared with the ketorolac-fentanyl combination.
Analgesia, Patient-Controlled* ; Analgesics* ; Cholecystectomy, Laparoscopic ; Fentanyl ; Humans ; Incidence ; Ketorolac* ; Nefopam* ; Pain, Postoperative ; Postoperative Nausea and Vomiting ; Prospective Studies* ; Respiration

BACKGROUND: Nitrous oxide (N2O) is much cheaper than recently introduced volatile anesthetics such as sevoflurane and desflurane, and can reduce the consumption of these anesthetics. The use of N₂O is under current debate. The purpose of this study was to evaluate economic effect of 50% N₂O during sevoflurane anesthesia in Korea. METHODS: Seventy patients were randomly allocated to Group A or Group N. Anesthesia induction was performed using propofol, rocuronium, and 3–5% of sevoflurane with air (Group A) or 50% N2O (Group N). Fresh gas flow (FGF) was 6 L/min during induction, and 3 L/min for maintenance. Mean arterial pressure (MAP), heart rate (HR), bispectral index (BIS), and minimum alveolar concentration (MAC) were recorded. The consumption of sevoflurane was measured at every 10 minutes for the first 1 hour. The economic effect was analyzed based on the payment criterion of Korean National Health Insurance Service. RESULTS: MAP, HR, BIS, and MAC showed no differences between the two groups. The sevoflurane consumptions for the first 1 hour were 39.2 ± 6.3 ml in Group A and 29.2 ± 4.9 ml in Group N (P < 0.01); and the N₂O consumption was 93.7 ± 1.5 L in Group N. The total costs of inhaled anesthetics were 16,190 (14.8 USD) and 13,062 (12.0 USD) Korean won for the first 1 hour in Groups A and N, respectively. CONCLUSIONS: Use of 50% N₂O with 3 L/min FGF reduced the sevoflurane consumption by 25% and anesthetic cost by 20% for the first 1 hour.
Anesthesia* ; Anesthetics ; Arterial Pressure ; Cost-Benefit Analysis* ; Heart Rate ; Humans ; Korea ; National Health Programs ; Nitrous Oxide* ; Propofol

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BACKGROUND: Although the use of postoperative opioids is a well-known risk factor for postoperative nausea and vomiting (PONV), few studies have been performed on the effects of intraoperative opioids on PONV. We examined the effects of a single bolus administration of fentanyl during anesthesia induction and the intraoperative infusion of remifentanil on PONV. METHODS: Two hundred and fifty women, aged 20 to 65 years and scheduled for thyroidectomy, were allocated to a control group (Group C), a single bolus administration of fentanyl 2 microg/kg during anesthesia induction (Group F), or 2 ng/ ml of effect-site concentration-controlled intraoperative infusion of remifentanil (Group R) groups. Anesthesia was maintained with sevoflurane and 50% N2O. The incidence and severity of PONV and use of rescue antiemetics were recorded at 2, 6, and 24 h postoperatively. RESULTS: Group F showed higher incidences of nausea (60/82, 73% vs. 38/77, 49%; P = 0.008), vomiting (40/82, 49% vs. 23/77 30%; P = 0.041) and the use of rescue antiemetics (47/82, 57% vs. 29/77, 38%; P = 0.044) compared with Group C at postoperative 24 h. However, there were no significant differences in the incidence of PONV between Groups C and R. The overall incidences of PONV for postoperative 24 h were 49%, 73%, and 59% in Groups C, F, and R, respectively (P = 0.008). CONCLUSIONS: A single bolus administration of fentanyl 2 microg/kg during anesthesia induction increases the incidence of PONV, but intraoperative remifentanil infusion with 2 ng/ml effect-site concentration did not affect the incidence of PONV.
Analgesics, Opioid ; Anesthesia ; Antiemetics ; Female ; Fentanyl* ; Humans ; Incidence ; Intraoperative Period ; Nausea ; Postoperative Nausea and Vomiting* ; Risk Factors ; Thyroidectomy ; Vomiting

BACKGROUND: The purpose of this study was to compare temperatures measured at three different sites where a nasopharyngeal temperature probe is commonly placed. METHODS: Eighty elective abdominal surgical patients were enrolled. After anesthesia induction, four temperature probes were placed at the nasal cavity, upper portion of the nasopharynx, oropharynx, and the esophagus. The placement of the nasopharyngeal temperature probes was evaluated using a flexible nasendoscope, and the depth from the nares was measured. The four temperatures were simultaneously recorded at 10-minute intervals for 60 minutes. RESULTS: The average depths of the probes that were placed in the nasal cavity, upper nasopharynx, and the oropharynx were respectively 5.7 ± 0.9 cm, 9.9 ± 0.7 cm, and 13.6 ± 1.7 cm from the nares. In the baseline temperatures, the temperature differences were significantly greater in the nasal cavity 0.32 (95% CI; 0.27-0.37)℃ than in the nasopharynx 0.02 (0.01-0.04)℃, and oropharynx 0.02 (−0.01 to 0.05)℃ compared with the esophagus (P < 0.001). These differences were maintained for 60 minutes. Twenty patients showed a 0.5℃ or greater temperature difference between the nasal cavity and the esophagus, but no patient showed such a difference at the nasopharynx and oropharynx. CONCLUSIONS: During general anesthesia, the temperatures measured at the upper nasopharynx and the oropharynx, but not the nasal cavity, reflected the core temperature. Therefore, the authors recommend that a probe should be placed at the nasopharynx (≈ 10 cm) or oropharynx (≈ 14 cm) with mucosal attachment for accurate core temperature measurement.
Anesthesia ; Anesthesia, General ; Body Temperature ; Esophagus ; Humans ; Nasal Cavity ; Nasopharynx ; Oropharynx ; Thermometers

BACKGROUND: The authors hypothesized that the continuous infusion of ramosetron 0.15 mg following a 0.15 mg bolus administration would maintain higher 5-hydroxytryptamine type 3 receptor occupancy levels and be more effective in preventing postoperative nausea and vomiting (PONV) than a 0.3 mg single bolus administration. We conducted a study to compare the efficacy of single bolus ramosetron administration with the combination of continuous infusion following intravenous bolus administration for PONV prophylaxis. METHODS: One hundred and fifty female patients undergoing thyroidectomy were allocated randomly to one of three groups to receive a placebo (Group 1, n = 49), 0.3 mg of IV ramosetron (Group 2, n = 53), or the continuous infusion of 0.15 mg ramosetron following a bolus administration of 0.15 mg of ramosetron (Group 3, n = 48). Anesthesia was maintained with sevoflurane and N2O. The incidence of PONV, nausea severity, and use of rescue antiemetics during the postoperative 24 hours were recorded. RESULTS: Group 1 showed higher incidences of PONV during the postoperative 24 hour than Group 2 (81% vs. 58%, P = 0.02) and Group 3 (81% vs. 48%, P < 0.01), but there was no difference between Groups 2 and 3 (P = 0.39). The use of rescue antiemetics was significantly lower in Groups 2 and 3 than Group 1 during the postoperative 6 to 24 hours. CONCLUSIONS: There were no significant differences of incidence and severity of PONV between ramosetron 0.3 mg single bolus administration and the combination of ramosetron infusion after 0.15 mg bolus administration.
Analgesia, Patient-Controlled ; Anesthesia ; Antiemetics* ; Female ; Humans ; Incidence ; Morphine ; Nausea ; Postoperative Nausea and Vomiting ; Serotonin ; Thyroidectomy