Verification of an intravenous fluid warmer: A prospective, two-center observational trial.

Objectives: Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmers used intraoperatively are critical for maintaining euthermia. We sought to prospectively evaluate the performance of the parylene-coated enFlow™ intravenous fluid warmer in patients undergoing surgery. Methods: This was a prospective two-center observational clinical trial performed in inpatient surgical services of two large academic hospital systems. After written informed consent, patients were enrolled in the trial. All patients were adults scheduled for a surgery that was expected to last for at least 1 h with the administration of at least 1 L of fluid warmed prior to infusion. Patient temperature was recorded in the preoperative unit, at the induction of anesthesia, and then every 15 or 30 min until the end of surgery. Temperature monitoring continued in the recovery unit. The parylene-coated enFlow™ intravenous fluid warmer was used in addition to the usual patient warming techniques. The primary outcome was the average core temperature, and secondary analyses assessed individual temperature measurements, temperature measurements during specific time periods, and rate of hypothermic events. Results: In all, 50 patients (29 males) with a mean age of 64 years were included in the analysis. The mean surgical time was 195 min and patients received an average of 1142 mL of fluids. Core temperature dropped by only 0.3°C approximately 60 min after induction and recovered back to the baseline level approximately 60 min later. There was no correlation between flow rate and measured core body temperature. Conclusions: The parylene-coated enFlow intravenous fluid warmer was able to warm fluids at all flow rates during prolonged surgery. The results showed that enFlow performed as expected.

Efficacy of thoracic epidural analgesia with or without intercostal nerve cryoanalgesia for postthoracotomy pain.

BACKGROUND: We evaluated effects of thoracic epidural analgesia combined with intercostal nerve cryoanalgesia or epidural analgesia alone on acute and long-term pain after posterolateral thoracotomy. METHODS: Forty-two elective thoracotomy patients were randomly assigned to two groups, epidural combined with cryoanalgesia or epidural alone. A thoracic epidural catheter was inserted before induction of anesthesia. At the end of the operation, cryoanalgesia was performed to 3 intercostals nerves: 1 at the level of the incision, 1 caudal, and 1 cranial. Cryoanalgesia was blinded to the investigating anesthetists and patients. To avoid impingement of intercostal nerves, chest closure in all patients was performed using intracostal sutures through drilled holes in adjacent ribs. In the postanesthesia care unit, epidural infusion of ropivacaine (1 mg/mL) with fentanyl (5 µg/mL) was started and continued 3 days. Thereafter, pain was treated with oral strong or weak opioids combined with nonsteroidal antiinflammatory drugs or acetaminophen. Pain was assessed with the verbal pain scale or visual analog scale. Patients visited a local pain clinic at 8 weeks and at 6 months postoperatively. RESULTS: The cryoanalgesia group had more neuropathic-type pain compared with the epidural-alone group 8 weeks after operation (p < 0.05). The cryoanalgesia group had also more pain on normal daily activities 8 weeks after the operation (p < 0.05). After 6 months, there were no statistically significant differences between groups. CONCLUSIONS: Intercostal cryoanalgesia seems to increase the incidence of long-term pain after thoracotomy.

Electroencephalographic burst suppression versus loss of reflexes anesthesia with propofol or thiopental: differences of variance in the catecholamine and cardiovascular response to tracheal intubation.

UNLABELLED: The electroencephalographic burst suppression pattern (BSP) might indicate the brain's effect-site concentration of anesthetics more precisely than clinical signs and thus eliminate bias from studies on the reaction to tracheal intubation after different induction drugs. To test this hypothesis, we compared the catecholamine and cardiovascular responses and their variances to tracheal intubation when either BSP was induced by infusion of propofol (30 mg x kg(-1) x h(-1); n = 14) or thiopental (75 mg x kg(-1) x h(-1); n = 14) or anesthesia by repeated bolus doses until loss of reflexes (LR), initially of propofol 2.5 mg/kg (n = 15) or thiopental 5 mg/kg (n = 15). The standard deviations were more often smaller in the BSP than in the LR groups, but the results of Levene's test for differences of variance were insignificant. At the LR level, propofol attenuated catecholamine, arterial blood pressure, and heart rate responses to intubation better than thiopental, but at the BSP level, only the norepinephrine response was better attenuated. Cp50 concentrations of propofol and thiopental at the onset of BSP were 9.65 and 31.60 micro g/mL, respectively. IMPLICATIONS: Our results did not support the hypothesis that the responses to tracheal intubation can be more accurately predicted when unconsciousness is controlled with the aid of an electroencephalographic burst suppression pattern. Significant differences were found in the reactions between propofol and thiopental. At the burst suppression level, the catecholamine response was abolished with propofol.