M. De Kock

Intrathecal ropivacaine for ambulatory surgery - A comparison between intrathecal bupivacaine and intrathecal ropivacaine for knee arthroscopy

Background The rationale of this study was to evaluate intrathecal ropivacaine for ambulatory surgery. Methods: One hundred fifty patients with American Society of Anesthesiologists physical status 1 scheduled for knee arthroscopy were studied. Patients were randomly assigned to receive 4 ml of one of five isobaric intrathecal solutions: Patients in group 1 (n = 30) received 8 mg of bupivacaine; patients in group 2 (n = 30) received 8 mg ropivacaine; patients in group 3 (n = 30) received 10 mg ropivacaine; patients in group 4 (n = 30) received 12 mg ropivacaine; and patients in group 5 (n = 30) received 14 mg ropivacaine. The level and duration of sensory anesthesia were recorded along with the intensity and duration of motor block. Patients were interviewed to identify transient neurologic symptoms. Results: Intrathecal ropivacaine 10 mg produced shorter sensory anesthesia and motor blockade than bupivacaine 8 mg (152 +/- 44 min and 135 +/- 41 min vs. 181 +/- 44 min and 169 +/- 52 min, mean +/- SD; P < 0.05). However, the quality of intraoperative analgesia was significantly lower in the 10-mg ropivacaine group (P < 0.05). Ropivacaine 12 mg produced sensory and motor block almost comparable to bupivacaine 8 mg. Ropivacaine 14 mg produced sensory and motor block comparable to ropivacaine 12 mg but significantly increased the time to void. No sign of transient radicular irritation mere noted. Conclusion: Intrathecal ropivacaine 12 mg is approximately equivalent to bupivacaine 8 mg. At this dose, ropivacaine offers no significant advantage compared with bupivacaine.

Epidural clonidine used as the sole analgesic agent during and after abdominal surgery : A dose-response study

BACKGROUND: Many studies have shown the beneficial effect of epidural clonidine in postoperative pain management. In these studies, the patients received local anesthetics, opioids, or both in combination with clonidine. Due to the interactive potentiation of those drugs, the importance of the intrinsic analgesic properties of the alpha 2-adrenoceptor agonist is difficult to establish. The authors investigated the analgesic potency of epidural clonidine when used as the sole analgesic agent during and after major abdominal surgery. METHODS: Fifty young adult patients undergoing intestinal surgery under general anesthesia with propofol were studied. At induction, the patients received epidurally either an initial dose of 2 micrograms/kg clonidine followed by an infusion of 0.5 microgram.kg-1.h-1 (group 1, n = 10) or 4 micrograms/kg followed by 1 microgram.kg-1.h-1 (group 2, n = 20) or 8 micrograms.kg-1.h-1 followed by an infusion of 2 micrograms.kg-1.h-1 (group 3, n = 20). During the operation, increases in arterial blood pressure or heart rate that did not respond to a propofol bolus (0.5 mg/kg) were treated with a bolus of intravenous lidocaine (1 mg/kg). Three successive injections were allowed. When baseline values were not restored, opioids were added and the patient was removed from the study. After operation, the clonidine infusions were maintained for 12 h. During this period and at every 30 min, sedation scores and visual analog scale values at rest and at cough were noted. In case of subjective scores up to 5 cm at rest or up to 8 cm at cough, the patients were given access to a patient-controlled analgesia device that delivered epidural bupivacaine. The end point of the study was reached once the patient activated the analgesic delivery button. RESULTS: During surgery, 60% of patients in group 1 compared with 33% of patients in group 2 and only 5% of patients in group 3 were removed from the study protocol because of inadequate anesthesia (P < 0.05). After operation, epidural clonidine provided complete analgesia lasting 30 +/- 21 min in group 1 compared with 251 +/- 237 min in group 2 or 369 +/- 256 min in group 3 (P < 0.05 for group 1 vs. groups 2 and 3 and group 2 vs. group 3). CONCLUSIONS: Epidural clonidine used as the sole analgesic agent provided dose-dependent control of the hemodynamic changes associated with surgical stimulation. It also produced dose-dependent postoperative analgesia without major side effects.

Intraoperative use of ketorolac or diclofenac is associated with improved disease-free survival and overall survival in conservative breast cancer surgery

BACKGROUND An association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and better outcome after mastectomy and lung surgery for cancer has been recently suggested. In a retrospective analysis, we investigated the association between intraoperative NSAIDs use in conservative breast cancer surgery and breast cancer disease-free survival (DFS). Similarly, we also evaluated the association between breast cancer DFS and preoperative neutrophil:lymphocyte ratio (NLR). METHODS A retrospective analysis of a single-centre cohort was performed in breast cancer patients (n=720) with uni- and multivariate analyses, using a Cox regression model. RESULTS In conservative breast cancer surgery, the intraoperative use of NSAIDs (ketorolac or diclofenac) was associated with an improved DFS {hazard ratio (HR)=0.57 [95% confidence interval (CI): 0.37-0.89], P=0.01} and an improved overall survival (OS) [HR=0.35 (95% CI: 0.17-0.70), P=0.03]. In these patients, an NLR >3.3 (identified by a receiver-operating characteristic curve) was associated with a shorter DFS [HR=1.99 (95% CI: 1.16-3.41), P=0.01] and OS [HR=2.35 (95% CI: 1.02-5.43), P=0.046]. CONCLUSIONS Intraoperative NSAIDs and higher preoperative NLR are associated with improved outcome in conservative breast cancer surgery. Prospective, randomized trials to evaluate if these associations are causal are warranted.

Clonidine pretreatment reduces the systemic toxicity of intravenous bupivacaine in rats.

Backgrounds:Clonidine prolongs the duration of sensory and motor block induced by bupivacaine, and this association, in constant infusion by the epidural route, is used for postoperative analgesia. After a near-fatal intravenous bolus of bupivacaine in dogs, clonidine improves ventricular electrophysiologic parameters, but probably worsens bupivacaine induced bradycardia and depression of the myocardial contractility. The current study, using a rodent animal model, evaluated the influence of clonidine pretreatment on the systemic toxic effects of bupivacaine overdose induced by a constant intravenous infusion. Methods:Twenty Wistar male rats were anesthetized with thiopental, and controlled ventilation was started with an equal mixture of O2 and N2O. Electrocardiogram (ECG), electroencephalogram (EEG), and invasive arterial blood pressure were continuously recorded. Clonidine (5 µg/kg) or saline was injected intravenously in a randomized fashion. After 15 min, an intravenous infusion of bupivacaine was started at 2 mg · kg−1 · min−1. The time of occurrence of the bupivacaine-induced toxic events was recorded and the doses were calculated. Ten (five in each group) additional rats, pretreated according to the same protocol, were killed at the time of the first dysrhythmia, for blood sampling and plasma bupivacaine concentration measurement. Results:Clonidine reduced heart rate and arterial blood pressure before bupivacaine infusion (P < 0.05). The threshold doses at the first QRS modification (11.3 ± 5.6 vs. 2.1 ± 0.9 mg/kg) and the first dysrhythmia (40.6 ± 15.3 vs. 8.48 ± 3.7 mg/kg), the increase In EEG total spectral power (33.3 ± 21.9 vs. 8.2 ± 5.1 mg/kg), the 25 and 50% reduction in baseline mean arterial pressure and heart rate, the isoelectric EEG (58.6 ± 14 vs. 22 ± 6.6 mg/kg), and the final systole (99 ± 16 vs. 51.8 ± 14.5 mg/kg) were significantly greater in the clonidine group than in the saline group (P < 0.01). The time between the first dysrhthymia and 50% reduction of baseline mean arterial blood pressure was not different between the groups. In the additional series, the first dysrhythmia occurred later (10.9 ±4.5 vs. 3.2 + 1.0 min, P < 0.01) and plasma bupivacaine levels were greater (18.7 ± 8.0 vs. 7.8 ± 3.2 µg/ml, P < 0.01) in the clonidine group than in the saline group. Conclusions:In this model, clonidine given prophylactically delays the toxic manifestations of bupivacaine overdose and does not accentuate the subsequent hypotension.

Hepatopulmonary syndrome and liver transplantation: a review of the peroperative management of seven paediatric cases.

Until recently, hypoxaemia was considered as a relative contraindication for liver transplantation. The hepatopulmonary syndrome associated with a right to left shunt of blood through the lungs is reversible in adults and children after correction of the cirrhosis by liver transplantation. However, concerns have been raised regarding the risks of anaesthesia in such hypoxaemic patients. Since the peroperative management of children undergoing liver transplantation and suffering from hepatopulmonary syndrome and severe hypoxemia has never been described, we report here our experience in seven children. Despite the fact that severe arterial desaturation was recorded throughout the procedure, no major complications were recorded peroperatively. The postoperative intubation time was 58 ± 21 h, five children being extubated while still hypoxaemic. All seven patients reversed their hepatopulmonary syndrome after a mean postoperative period of 24±10 weeks. This shows that liver transplantation can be successfully achieved in severely hypoxaemic children and that postoperative correction of the right to left shunt is then obtained.

In vivo optical spectroscopy monitoring in a new model of muscular compartment syndrome

BACKGROUND Muscular compartment syndrome (MCS) is a rare but serious postoperative complication. In vivo optical spectroscopy (INVOS) monitors continuously and non-invasively regional oxygen saturation (rSO(2)), and could predict the development of MCS. METHODS In 10 healthy volunteers, we inflated a tourniquet to the mean arterial pressure to produce slight venous congestion and arterial hypoperfusion. Comparisons were made between the relative reduction in rSO(2) with baseline (deltaINVOS) and the time to observe motor nerve block (with non-invasive electromyography). Neurological symptoms, pain, and invasive intracompartmental pressure (ICP) were assessed. RESULTS In the eight volunteers completing the protocol, we observed a profound motor nerve conduction block, immediately reversible. Baseline values were: [mean (sd)] INVOS: 73.3 (8.9)% and ICP: 16.9 (8.6) mm Hg. At the time of the block, values were: INVOS: 46.4 (10.9)%, deltaINVOS: 28.7 (10.6)%, and ICP: 70.0 (5.5) mm Hg. The time to reach the block was 33.0 (10.9) min, and to a deltaINVOS>10%: 27.4 (10.4) min. Receiver-operating characteristic curves demonstrated a similar accuracy of ICP and INVOS to predict the occurrence of the block. Twenty minutes with a deltaINVOS>10% or ICP>30 mm Hg were associated with a sensitivity and a specificity of 95% and 70%; or 91% and 65%, respectively. CONCLUSIONS We have developed a model of acute immediately reversible MCS. Monitoring using the INVOS technology is as accurate as measurement of ICP, and could be a useful tool to prevent development of intraoperative MCS.