High-dose intraoperative remifentanil infusion increases early postoperative analgesic consumption: a prospective, randomized, double-blind controlled study.

PURPOSE: The purpose of this study was to determine whether intraoperative infusion of remifentanil induces acute tolerance to opioids, and compare the postoperative pain and opioid consumption by the effect site concentrations of remifentanil. METHODS: One hundred and ninety-eight patients undergoing gastrectomy were randomly assigned to maintain target effect site concentrations of remifentanil at 0 (Group 1, n = 39), 2 (Group 2, n = 40), 4 (Group 3, n = 39), 8 (Group 4, n = 40), or 12 ng/ml (Group 5, n = 40) during operation. Postoperative pain intensities and fentanyl requirement were recorded at postoperative 2, 6, 24, and 48 h. RESULTS: Fentanyl requirement for postoperative 2 h was significantly greater in Group 5 compared to Group 1 (376 ± 116 vs. 283 ± 129 µg, P = 0.03). However, there were no differences in fentanyl requirements among the groups after postoperative 2 h. Also, total fentanyl consumption for 48 h was similar in all groups (Group 1; 3106 ± 629, Group 2; 2970 ± 705, Group 3; 3017 ± 555, Group 4; 3151 ± 606, and Group 5; 2984 ± 443 µg, P = 0.717). Pain scores at rest and during deep breathing were comparable in all groups at the time of each examination. CONCLUSION: Intraoperative infusion of remifentanil with 12 ng/ml of effect site concentration in patients undergoing gastrectomy increases early postoperative fentanyl requirement. Acute opioid tolerance would be developed by higher concentration of remifentanil than dosage of common anesthetic practice.

Intrathecal ketamine and pregabalin at sub-effective doses synergistically reduces neuropathic pain without motor dysfunction in mice.

Peripheral or central nerve injury often leads to neuropathic pain. Although ketamine and pregabalin are first line options for the treatment of neuropathic pain, their clinical application is limited due to side effects such as sedation, dizziness and somnolence. We designed this study to determine whether the intrathecal (i.t.) co-treatment with ketamine and pregabalin at sub-effective low doses would elicit a sufficient pain relief without producing side effect in a neuropathic pain mouse model. At day 7 after chronic constriction injury (CCI) of sciatic nerve, dose dependent effects of i.t. ketamine (3, 10, 30, 100 µg) or i.t. pregabalin (10, 30, 100 µg) on mechanical allodynia and thermal hyperalgesia were measured. For combination treatment, 3 or 10 µg of ketamine and 30 µg of pregabalin were selected because these doses of drugs were not effective on neuropathic pain. Interestingly, combined i.t. treatment groups (ketamine 3 µg+pregabalin 30 µg and ketamine 10 µg+pregabalin 30 µg) produced strong analgesia on neuropathic pain although these doses of ketamine and pregabalin alone are not effective. Moreover, rota rod test revealed that normal motor function was not affected by combined treatment while i.t. ketamine at doses above 10 µg showed a significant motor dysfunction. Results of this study suggested that i.t. co-treatment with ketamine and pregabalin at sub-effect low doses may be a useful therapeutic method for the treatment of neuropathic pain patients.

Reliability of assessment of nasal flow rate for nostril selection during nasotracheal intubation.

STUDY OBJECTIVE: To evaluate the reliability of assessments of nasal flow rate for improved nostril selection for nasotracheal intubation. DESIGN: Prospective, randomized, double-blinded study. SETTING: Operating room of a university-affiliated hospital. PATIENTS: 118 ASA physical status 1 and 2 patients, aged 18-65 years, scheduled for elective maxillofacial and oral surgery requiring nasotracheal intubation. INTERVENTIONS: Patients were randomized to the left or right nostril groups. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV(1)) through the mouth and each nostril were measured before anesthesia induction. MEASUREMENTS: The relationship between the rate of airflow through the selected nostril and frequency of epistaxis and navigability of the nasotracheal tube were evaluated. MAIN RESULTS: There were no significant differences in the frequency of epistaxis and degree of navigability of the tracheal tube between the left and right nostril groups. In both nostril groups, patients who suffered epistaxis showed significantly less FEV(1) and FEV(1)/FVC values than did patients without epistaxis (P < 0.05). In addition, in both groups patients who passed the tube easily showed significantly higher FEV(1) and FEV(1)/FVC values than did patients who passed the tube with resistance or failed tube passage (P < 0.05). CONCLUSION: Measurement of nasal flow rate is a useful clinical method for choosing a nostril for nasotracheal intubation.

Computer-assisted three-dimensional reconstruction of the fetal pancreas including the supplying arteries according to immunohistochemistry of pancreatic polypeptide.

PURPOSE: Computer-assisted three-dimensional reconstruction of the fetal human pancreas was prepared to reconsider topographical relation between the dorsal/ventral anlagen and the vascular supply. METHODS: Tissue sections from the upper abdominal viscera of three fetuses were examined. Sections were immunohistochemically stained to determine pancreatic polypeptide expression, a marker of the ventral pancreas. RESULTS: The immunohistochemical findings were used to create three-dimensional computer-assisted reconstructions to identify pancreatic arteries. The narrowest part of the pancreas, or the neck, corresponding to a part of the dorsal pancreas, was located on the left side of the common bile duct, portal vein and gastroduodenal artery (GDA). The posterior arterial arcade accompanied the ventral pancreas, whereas the anterior arcade did not. In contrast to the GDA, the splenic artery was clearly separated from the neck in fetuses. The GDA appears to be the primary and stable arterial supply for the neck of the pancreas. CONCLUSIONS: This observation may have implications for the preservation of the neck with the GDA during pancreaticoduodenectomy for benign and low-grade malignant diseases.

Isoflurane cracks the polycarbonate connector of extra-corporeal circuit -A case report-.

Cardiopulmonary bypass (CPB) is widely used for cardiac surgery by virtue of its proven safety over the course of its use during the past half century. Even though perfusion is safer, incidents still occur. During the repair of a ventricular-septal defect in an 11-month-old infant, we experienced a critical incident related to the potential hazardous effect of volatile anesthetics on the polycarbonate connector of extra-corporeal circuit. The damage to the polycarbonate connector had occurred after spillage of isoflurane during the filling of the vaporizer, causing it to crack and leak. The incident was managed by replacement of the cracked connector during a temporary circulatory arrest. The patient was hypothermic and the time off bypass was less than 1.5 min. There were no neurologic sequelae, the patient made an uneventful recovery. In conclusion, the spillage of volatile anesthetics can cause cracks in the polycarbonate connector of the extra-corporeal circuit, leading to potentially interruption of CPB.

A comparison of the consumption of inhaled anesthetics according to fresh gas flow and anesthetic circuits.

BACKGROUND: In the Korean National Health Insurance Corporation (KNHIC), payment for inhaled anesthetics are made according to the simulated dose and not the consumed dose. We compare the consumption of inhaled anesthetics according to fresh gas flow (FGF) and anesthetic circuits to compare the consumption of anesthetics and the guidelines for KNHIC payments. METHODS: 161 patients were randomized into six groups who received isoflurane using a closed circuit (group I-C), a semi-closed circuit with FGF 3 L/min (group I-3), or 4 L/min (group I-4), as for the sevoflurane group (group S-C, S-3, and S-4). Mean arterial pressure (MAP) and heart rate (HR) were maintained within +/- 20% of baseline. Minimum alveolar concentration (MAC) and consumption of inhaled anesthetics were recorded by a new anesthetic machine. RESULTS: There were no significant differences among the groups for MAP, HR, and MAC. During anesthesia maintenance, the mean consumption per 15 minutes of inhaled anesthetics was significantly lower in group I-C (1.0 +/- 0.3 ml) than in group I-3 (3.5 +/- 0.7 ml) and than group I-4 (4.9 +/- 0.9 ml) and similar to the sevoflurane groups (group S-C [1.3 +/- 0.4 ml] vs group S-3 [5.3 +/- 1.0 ml] vs group S-4 [6.9 +/- 1.3 ml], respectively; P < 0.05). CONCLUSIONS: In sevoflurane groups, inhaled anesthetics were consumed more than in isoflurane groups. The KNHIC payment guidelines were close to the actual consumption of inhaled anesthetics under using a semi-closed circuit with FGF 3 L/min in sevoflurane and FGF 4 L/min in isoflurane.

Anatomical variations of the origin of the segment 4 hepatic artery and their clinical implications.

The threat of ischemic complications following massive resection, especially in living donor hepatectomy or split liver transplantation, has been haunting surgeons for many years. Postmortem dissections of 62 livers were performed to investigate anatomical variations of the principal artery for segment 4 (A4). The origin of A4 was examined separately in the liver with (n = 46) or without (n = 16) an aberrant left hepatic artery (abLHA). A4s were found to be extrahepatic or intrahepatic branches of the right hepatic artery (RHA), left hepatic artery, or proper hepatic artery and were categorized into 4 different types according to their origins. The RHA type, originating from the RHA or right anterior hepatic artery (RAHA), was the most common pattern in our series. The A4 roots had a strong tendency of stemming from the RHA (n = 12) even in the livers with abLHA (n = 16). Among the RHA-type A4s, the A4 arising from RAHA (n = 2) is supposed to be the most dangerous variant because it can cause an ischemic change in the remaining part of the liver after right hepatectomy. In conclusion, in the era of living donor liver transplantation, paying particular attention to the point of origin of A4 is a prerequisite, especially when the lateral section is relatively small. Arterial injuries to A4 during split liver transplantation may also increase the risk of hepatic artery thrombosis and ischemic cholangiopathy.