Search

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., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: ML, SM, KR, JJ, and VK have no competing interests. The actual research including case extraction and data analysis were performed by an outside clinical research organization, Clinius Oy (VK). DB, ER, HG, and AW are affiliated with Vyaire Medical. SC is an independent consultant. This manuscript and all attached tables and figures were reviewed and approved by all authors., (© The Author(s) 2023.)

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., (Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Some reports show no interaction between propofol and opioids, whereas others state such interactions. We evaluated the influence of remifentanil on propofol requirements at certain anesthesia end-points., Methods: Elective surgical patients were randomly assigned to three groups of 15 patients each. Premedication was with oral diazepam 0.1 mg kg(-1). Patients were blindly given equal volumes of saline or remifentanil (7.5 or 30 microg kg(-1). h(-1)) 1 min before induction of anesthesia with infusion of propofol, 30 mg kg(-1). h(-1). We recorded times to, propofol requirements, and bispectral index at loss of counting (LC), loss of verbal command (LVC), loss of reaction to tetanic stimulation (LRT), and onset of burst suppression pattern (BSP) of electroencephalography., Results: In the remifentanil groups end-points were attained significantly faster and with lower doses of propofol than in the saline group. BIS-values were significantly different at LRT and BSP end-points., Conclusions: We conclude that remifentanil infusion started before induction of propofol anesthesia significantly reduces propofol requirements at all end-points. The results suggest that remifentanil accelerates the hypnotic onset of propofol.

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.

Effective plasma concentrations of propofol, thiopentone and ketamine were determined at different endpoints in a study with randomized, crossover design in nine New Zealand White rabbits. A continuous infusion was used (30 ml/h) with concentrations of 10 mg/ml for propofol, 25 mg/ml for thiopentone and 20 mg/ml for ketamine. The endpoints were loss of the righting reflex, loss of purposeful reactions to tail clamping (as an example of a peripheral pain stimulus) or to intranostril insufflation of ammonia vapour (as an example of a central reflex stimulus), and the recovery of these reflexes and reactions. According to the ED50 values the potency ratios of propofol, thiopentone and ketamine were at the loss of righting reflex 1:1.8:1.2, at the loss of reaction to ammonia vapour 1:1.5:1.6, and at the loss of reaction to tail clamping 1:1.5:3.9, respectively. Recovery was significantly faster after propofol than after thiopentone and ketamine. Measuring the effective plasma concentrations of intravenous anaesthetics provides a method of relating dose to effect, but there still remains a variable gap between plasma concentration and effect.

We compared the haemodynamic responses to endolaryngeal procedures during anaesthesia with propofol or thiopentone. Two minutes after administration of glycopyrronium 4 micrograms.kg-1 and alfentanil 17.5 micrograms.kg-1 anaesthesia was induced with either propofol 2.0 mg.kg-1 (n = 8) or thiopentone 5.0 mg.kg-1.min-1, respectively. Muscle relaxation was induced and maintained with suxamethonium. Intratracheal jet-ventilation (rate: 20 breath.min-1) was with 100% oxygen. Blood samples for later determination of plasma catecholamines were drawn and haemodynamic responses were recorded at tracheal intubation, after insertion of the operating laryngoscope, during the endolaryngeal procedure and after extubation. With both anaesthetic agents the only statistically significant haemodynamic response to intubation was a rise of heart rate. With propofol, plasma adrenaline concentrations decreased significantly after induction and remained below baseline values throughout the procedure. After insertion of the operating laryngoscope the haemodynamic response was more pronounced with thiopentone than with propofol. Propofol blocks the catecholamine and haemodynamic responses to endolaryngeal procedures more effectively than thiopentone.