Konstantinos Karakoulas

Clonidine versus ketamine to prevent tourniquet pain during intravenous regional anesthesia with lidocaine

Background and Objectives Both clonidine and ketamine have been found to prolong the action of local anesthetics through a peripheral mechanism. Our study compares the efficacy of a low dose of clonidine or ketamine separately added to intravenous regional anesthesia (IVRA) with lidocaine to prevent tourniquet pain. Methods We conducted a prospective randomized double-blinded study in 45 patients undergoing hand or forearm surgery, with anticipated duration exceeding 1 hour under IVRA. Proximal cuff inflation of a double tourniquet was followed by administration of 40 mL of lidocaine 0.5% and either saline, 1 μg/kg clonidine, or 0.1 mg/kg ketamine. When anesthesia was established, the inflation of the proximal and distal cuff was interchanged. Thereafter, tourniquet pain was rated on a visual analog scale (VAS) every 10 minutes. Intraoperatively, boluses of 25 μg fentanyl were provided for tourniquet pain treatment when required, and total fentanyl consumption was recorded. Results Patients receiving plain lidocaine persistently reported the highest pain scores among groups (P < .001) 20 minutes after distal cuff inflation. Differences between the groups with additional treatment were noted 50 minutes after distal cuff inflation and until the end of the observation, with significantly lower VAS ratings (P < .001 to P < .01) in ketamine-treated patients. Total fentanyl consumption was significantly decreased by ketamine (70.00 ± 25.35 μg) or clonidine (136.67 ± 39.94 μg) compared with the plain lidocaine group (215.33 ± 52.33 μg) (P < .001 between all groups). Conclusions The addition of clonidine 1 μg/kg or ketamine 0.1 mg/kg to lidocaine for IVRA delays the onset of unbearable tourniquet pain and decreases analgesic consumption for tourniquet pain relief, although ketamine has a more potent effect.

Rocuronium duration of action under sevoflurane, desflurane or propofol anaesthesia.

Background and objective: We conducted a prospective randomized study to evaluate whether the duration of action of a single bolus dose of rocuronium is influenced by maintenance of anaesthesia with sevoflurane, desflurane or propofol infusion. Methods: Fifty-seven ASA I-II patients undergoing elective abdominal surgery were enrolled in this study. Anaesthesia was induced with thiopental 3-5 mg kg−1 or propofol 2.5 mg kg−1 and fentanyl 5 μg kg−1 and tracheal intubation was facilitated with rocuronium 0.9 mg kg−1. Thereafter patients were randomly allocated to three different groups to receive sevoflurane, desflurane or propofol for maintenance of anaesthesia. Recovery of neuromuscular function was monitored by single twitch stimulation of the ulnar nerve and by recording the adductor pollicis response using accelerometry. Intergroup recovery times to 5% of control value of single twitch were analysed using analysis of variance with Bonferroni correction. Results: The mean (95% confidence interval) recovery time to 5% of control value of single twitch during desflurane anaesthesia was 90.18 (86.11-94.25) min. Significantly shorter recovery times were observed during sevoflurane or propofol anaesthesia, 58.86 (54.73-62.99) min and 51.11 (45.47-56.74) min, respectively (P < 0.001). There were also significant differences in the recovery time between groups receiving desflurane vs. sevoflurane (P < 0.001) and desflurane vs. propofol (P < 0.001). Conclusions: Desflurane anaesthesia significantly prolongs the duration of action of rocuronium at 0.9 mg kg−1 single bolus dose, compared to sevoflurane or propofol anaesthesia maintenance regimens.

Comparison between the Combination of Gabapentin, Ketamine, Lornoxicam, and Local Ropivacaine and Each of these Drugs Alone for Pain after Laparoscopic Cholecystectomy: A Randomized Trial

The main purpose of the study was to test whether the combination of gabapentin (600 mg 4 hours before surgery, 600 mg after 24 hours), ketamine (0.3 mg/kg before anesthesia), lornoxicam (8 mg before anesthesia and 8 mg/12 hours), and local ropivacaine (5 mL 7.5% at insertion sites) provides superior analgesia to each of these drugs alone in the first 24 hours after laparoscopic cholecystectomy. The secondary purpose was to examine whether this combination has less opioid‐related side effects.

Correlation of central venous-arterial and mixed venous- arterial carbon dioxide tension gradient with cardiac output during neurosurgical procedures in the sitting position

Background and objective The study was conducted to evaluate the correlation of central venous–arterial and mixed venous–arterial pCO2 gradient with cardiac output in patients being operated in the sitting position. Methods Fifty-one patients, aged 41–69 years, classified as American Society of Anesthesiologists physical status II and III, scheduled to undergo elective neurosurgical procedures in the sitting position, were enrolled in this prospective cohort study. Simultaneous blood gas samples from arterial, central venous and pulmonary artery catheters were collected at four different time points during supine and sitting position. Cardiac index (CI) determination was accomplished simultaneously, with continuous cardiac output technique. The mixed venous–arterial pCO2 and central venous–arterial pCO2 gradients were calculated and related to CI at the specific time points, thus a total of 204 points of comparison were obtained. Results Changing from the supine to the sitting position induced a significant deterioration of CI, right atrial pressure, mean pulmonary arterial pressure and pulmonary wedge pressure. The mean delta pCO2 difference (bias) in the four time points ranged between −0.07 and −0.27. The upper (1.59–1.71 mmHg) and lower limits of agreement (−2.16 to −1.82 mmHg) were quite narrow, suggesting an acceptable overall agreement between the mixed and central venous pCO2 differences. The coefficient of determination (R2) between the venous–arterial pCO2 and CI for mixed and central venous circulations was 0.830 and 0.760 (P < 0.001 for both), respectively. In contrast, R2 values between mixed and central venous oxygen saturation values and CI were 0.324 and 0.286, respectively (P < 0.001 for both), illustrating a rather weak relationship. Conclusion It seems that venous–arterial pCO2 values obtained from mixed and central venous circulations can be reliably interchanged in estimating CI in patients undergoing neurosurgical procedures in the sitting position. Thus, central venous–arterial pCO2 gradient could serve as a useful and simple method for estimating cardiac performance, in which further invasive monitoring is not strongly indicated.

Postoperative analgesia after low-frequency electroacupuncture as adjunctive treatment in inguinal hernia surgery with abdominal wall mesh reconstruction

Objective To determine whether an electroacupuncture (EA) technique that was developed for a surgical population under general anaesthesia reduces pain after mesh inguinal hernia open repair. Methods A total of 54 patients with right or left inguinal hernia were randomised to group I (preoperative, intraoperative, postoperative EA), group II (preoperative, postoperative EA), or a sham control group (group III; preoperative and postoperative placement of needles, but without skin penetration). The Visual Analogue Scale (VAS) (primary outcome) and the State-Trait Anxiety Spielberger Inventory were evaluated preoperatively and at 30 min, 90 min, 10 h and 24 h after surgery. Pain threshold and tolerance were evaluated using an algometer at these same time points and preoperatively before and after EA. Levels of the stress hormones cortisol, corticotrophin and prolactin were determined at 30 min, 90 min and 10 h after surgery and preoperatively before and after EA. Results The results showed significant differences between the true EA and control groups. The true EA groups (I and II) showed statistically significantly greater improvements in the primary (VAS pain, p<0.05) and secondary outcome measures (Anxiety scale; algometer measurements, p<0.05 and stress hormones, p<0.01) compared to the control group. There were no statistically significant differences between groups I and II. Conclusions Electroacupuncture reduces postoperative pain after mesh inguinal hernia repair and decreases stress hormone levels and anxiety during the postoperative period. Trial Registration Number ClinicalTrials.gov identifier NCT01722253.

Reliability of continuous jugular venous bulb hemoglobin oxygen saturation during cardiac surgery

OBJECTIVE To evaluate the accuracy and reliability of continuous measurement of jugular venous bulb hemoglobin oxygen saturation (SjvO2) with a fiberoptic catheter (SjvO(2OX)) during cardiac surgery versus simultaneous paired measurements of hemoglobin oxygen saturation by the Hemoximeter (SjVO(2HEM); Radiometer, Copenhagen, Denmark) and indirect estimations of hemoglobin oxygen saturation from measurements of partial pressure of oxygen in blood gases (SjVO(2BG)). DESIGN A prospective study. SETTING American Hellenic Educational Progressive Association General Hospital, University Hospital of Thessaloniki, Greece. PATIENTS Thirty patients undergoing elective aortocoronary artery bypass surgery. INTERVENTIONS In addition to routine pressure monitoring, a 4F fiberoptic catheter was placed in the left jugular bulb by a retrograde internal jugular vein approach and SIvO(2OX) was continuously measured. Before insertion, each catheter was calibrated in vitro. MEASUREMENTS AND MAIN RESULTS One hundred twelve simultaneous paired recordings between SjvO(2OX) and SjVO2BG were performed to define the accuracy of SjVO(2OX) to SjVO(2BG). Sixty-one of 112 simultaneous paired recordings between SjvO(2OX) and SjVO(2HEM) and SjVO(2HEM) and SjVO(2BG) were performed to define the accuracy of SjvO(2OX) to the reference SjVO(2HEM) and the reliability of the SjVO(2BG) measurement to SjVO(2HEM). The fiberoptic catheter readings varied from underestimating to overestimating hemoglobin saturation by a mean of -5.35% to +9.67% and of -3.22% to +7.81% versus Blood Gas Analyzer (Ciba-Corning) and Co-Oximeter (OSM 2b Hemoximeter, Radiometer) values, respectively. The mean underestimation and overestimation of Co-Oximeter versus Blood Gas Analyzer values were -3.18% and +4.17%, respectively. CONCLUSION SjvO2 values obtained continuously from a jugular venous bulb fiberoptic catheter may give relatively accurate readings provided they are duly interpreted and errors caused by wall artifact or blood sampling are avoided.

Interaction of a Cannabinoid-2 Agonist With Tramadol on Nociceptive Thresholds and Immune Responses in a Rat Model of Incisional Pain.

The aim of this study was to elucidate the antinociceptive interaction between cannabinoids and tramadol and their impact on proinflammatory response, in terms of serum intereleukin-6 (IL-6) and interleukin-2 (IL-2) release, in a rat model of incisional pain. Prospective randomized trial assessing the individual or combined application of intraperitoneal tramadol (10 mg/kg) and the selective cannabinoid-2 (CB-2) agonist (R,S)-AM1241 (1 mg/kg) applied postsurgical stress stimulus. Pharmacological specificity was established by antagonizing tramadol with naloxone (0.3 mg/kg) and (R,S)-AM1241 with SR144528 (1 mg/kg). Thermal allodynia was assessed by hot plate test 30 (T30), 60 (T60), and 120 (T120) minutes after incision. Blood samples for plasma IL-6 and IL-2 level determination were obtained 2 hours after incision. Data from 42 rats were included in the final analyses. Significant augmentation of thermal threshold was observed at all time points, after administration of either tramadol or (R,S)-AM1241 compared with the control group (P = 0.004 and P = 0.015, respectively). The combination of (R,S)-AM1241 plus tramadol promoted the induced antinociception in an important manner compared with control (P = 0.002) and (R,S)-AM1241 (P = 0.022) groups. Although the antiallodynic effect produced by tramadol was partially reversed by naloxone 30 and 60 minutes after incision (P = 0.028 and P = 0.016, respectively), SR144528 blocked the effects of (R,S)-AM1241 administration in a significant manner (P = 0.001) at all time points. Similarly, naloxone plus SR144528 also blocked the effects of the combination of (R,S)-AM1241 with tramadol at all time points (P = 0.000). IL-6 level in (R,S)-AM1241 plus tramadol group was significantly attenuated compared with control group (P = 0.000). Nevertheless, IL-2 levels remained unchanged in all experimental groups. It seems that the concomitant administration of a selective CB-2 agonist with tramadol in incisional pain model may improve antinociceptive effects and immune responses of cannabinoids, but this effect does not seem to be superior to that of tramadol alone.

Electrodermal Activity during Blood Pooling for Arterial Blood Gases Analysis in Sedated Adult Intensive Care Unit Patients

Electrodermal activity (EDA) is considered a measure of autonomous nervous system activity. This study performed an exploratory analysis of the EDA changes during blood pooling for arterial blood gas analysis in sedated adult critical care patients and correlated the variations to other monitored parameters. EDA, along with other parameters, were monitored during 4 h routine daytime intensive care nursing and treatment in an adult ICU. 4 h measurements were divided into two groups based upon the sedation level. Selected recordings before and after blood pooling for arterial blood gases analysis (stress event) was performed. Nine stress events from Group A and 17 from Group B were included for further analysis. Patients’ demographics, laboratory exams, and severity scores were recorded. For both sedation levels, EDA changes are much greater than any other monitoring parameters used. The changes are noticed in both measurement (15 s and 60 s), even though in the 60 s measurement only selected EDA parameters are significantly changed after the start of the procedure. EDA measurements are more sensitive to a given stress event than cardiovascular or respiratory parameters. However, the present results could only be considered as a pilot study. More studies are needed in order to identify the real stress-load and clinical significance of such stimuli, which are considered otherwise painless in those patients.

Electrodermal Activity Monitoring during Endotracheal Suction in Sedated Adult Intensive Care Unit Patients

Abstract Background: Endotracheal suctioning of respiratory secretions is one of the most common causes of pain and discomfort in Intensive Care Unit environment. The electrical properties of the skin, also known as electrodermal activity (EDA), are considered as an indirect measure of autonomous nervous system. Aim: This study explores EDA changes during endotracheal suction in sedated adult critical care patients; and compares these changes to other monitoring parameters. Materials and methods: Skin conductance variability, selected hemodynamic and respiratory parameters, bispectral index (BIS) and ambient noise level, were monitored during 4 hour routine daytime intensive care nursing and treatment in an adult Intensive Care Unit. 4h-measurements were divided into 2 groups, based upon the sedation level (group A: Ramsay sedation scale 2-4 and group B: 5-6 respectively) of the patients. Selected recordings before and after endotracheal suction (stress events) were performed. Seven stress events from Group A and 17 from Group B were included for further analysis. Patients’ demographics, laboratory exams and severity scores were recorded. Pain status evaluation before every event was also performed via 2 independent observers. Results: In both groups the rate of EDA changes was greater than in other monitoring parameters. Yet, in group A only selected parameters were significantly changed after the start of the procedure, while in group B, every parameter showed significant change (p<0.05). Groups were similar for other co-founding factors. Conclusion: EDA measurements are more sensitive to stress stimuli, than cardiovascular, respiratory or even BIS monitoring. Deeper sedation seems to affect more the intensity of EDA changes during suction.

Cerebral Oxygenation Impairment and S-100β Protein Release During Off-Pump Coronary Artery Revascularization

OBJECTIVE To elucidate the magnitude of global cerebral oxygenation impairment, using cerebral oxygenation indices and S-100β protein as potential markers, during off-pump coronary artery bypass grafting (OPCAB). DESIGN Prospective cohort study. SETTING Tertiary cardiac center. PARTICIPANTS Thirty-five patients undergoing OPCAB. INTERVENTIONS Jugular bulb and arterial blood samples for cerebral oxygenation indices (arterial oxygen and carbon dioxide partial pressures, jugular bulb oxygen saturation, arterial-jugular bulb oxygen content, arterial-jugular carbon dioxide partial pressure, brain oxygen extraction ratio, and estimated respiratory quotient) and S-100β protein determination were collected at anesthesia induction; anterior, inferior, and posterior wall anastomoses; after sternal closure; and 6 hours postoperatively. Concomitant hemodynamic data were obtained. The S-100β determination was extended to 12 and 24 hours postoperatively. MEASUREMENTS AND MAIN RESULTS Heart positioning for the target vessel exposure induced significant hemodynamic deterioration (p < 0.001). Although cerebral oxygenation indices were influenced adversely by a low-cardiac-output state mainly during vertical heart dislocation (p < 0.001), they remained within normal limits. Hemodynamic and cerebral oxygenation statuses reverted to baseline within 6 hours postoperatively. Similarly, S-100β jugular bulb and arterial protein levels presented a gradual increase, which peaked by the end of surgery (means, 0.54 and 0.62 μg/L, respectively; p < 0.001) and then decreased by the first postoperative day. Jugular bulb-arterial S-100β levels were maximized during posterior wall anastomosis (0.098 μg/L; p < 0.01). CONCLUSION Although exposure of the 3 main coronary arteries during OPCAB promotes derangement of the cerebral oxygen indices and S-100β release, this seems to be transient, remains within the near-normal range, and is reversible almost completely 6 hours postoperatively.