Bernard Vanacker

Reversal of rocuronium-induced neuromuscular block with the novel drug sugammadex is equally effective under maintenance anesthesia with propofol or sevoflurane

In this study we investigated whether the novel reversal drug, sugammadex, is equally effective at reversing rocuronium-induced neuromuscular block (NMB) in patients under propofol or sevoflurane maintenance anesthesia. After receiving propofol for induction, patients were randomized to propofol (n = 21) or sevoflurane (n = 21). Rocuronium 0.6 mg/kg was administered for tracheal intubation. NMB was monitored using acceleromyography. At reappearance of the second twitch of the train-of-four ratio, sugammadex 2.0 mg/kg was administered by IV bolus. The primary end-point was time from start of sugammadex administration to recovery of train-of-four ratio to 0.9. Mean recovery time was 1.8 min after both propofol and sevoflurane anesthesia. The 95% confidence interval for the difference in recovery time between the 2 groups (–0.5 to +0.4 min) was well within the predefined equivalence interval (–1 to +1 min), indicating that recovery from NMB was unaffected by maintenance anesthesia. Thirteen patients (propofol n = 4; sevoflurane n = 9) experienced adverse events; these were treatment-related in 4 patients (propofol n = 3; sevoflurane n = 1). There were no treatment-related serious adverse events and no discontinuations or deaths. No residual paralysis occurred. The safety profile of sugammadex was somewhat more favorable under propofol than under sevoflurane anesthesia.

Sugammadex Provides Faster Reversal of Vecuronium- Induced Neuromuscular Blockade Compared with Neostigmine: A Multicenter, Randomized, Controlled Trial

BACKGROUND: Sugammadex, a specifically designed &ggr;-cyclodextrin, is a selective relaxant binding drug that rapidly reverses rocuronium-induced and, to a lesser extent, vecuronium-induced neuromuscular blockade. In this study, we compared the efficacy of sugammadex and neostigmine for the reversal of vecuronium-induced neuromuscular blockade in patients scheduled for elective surgery. METHODS: Patients aged ≥18 yr, ASA Class I–III, and scheduled for a surgical procedure under sevoflurane/opioid anesthesia received an intubating dose of vecuronium (0.1 mg/kg) and maintenance doses of 0.02–0.03 mg/kg at reappearance of the second twitch (T2) of train-of-four (TOF) if required. Neuromuscular blockade was monitored using acceleromyography (TOF-Watch® SX, Schering-Plough Ireland, Dublin, Ireland). At end of surgery, at reappearance of T2 after the last dose of vecuronium, patients were randomized to receive either sugammadex (2 mg/kg) or neostigmine (50 &mgr;g/kg) plus glycopyrrolate (10 &mgr;g/kg) IV. The primary efficacy end-point was time from start of administration of sugammadex or neostigmine to recovery of TOF ratio to 0.9. RESULTS: The geometric mean time to recovery of the TOF ratio to 0.9 was significantly faster with sugammadex compared with neostigmine (2.7 min [95% confidence interval {CI}]: 2.2–3.3) versus 17.9 min [95% CI: 13.1–24.3], respectively; P < 0.0001). The mean recovery times to a TOF ratio of 0.8 and 0.7 were also significantly shorter with sugammadex. No serious adverse events or unexpected side effects were reported with either drug. CONCLUSION: Sugammadex provided significantly faster reversal of vecuronium-induced neuromuscular blockade compared with neostigmine.

The effect of prophylactic clonidine on postoperative shivering : A large prospective double-blind study

The primary goal of this study was to assess the influence of clonidine administered after induction on postoperative shivering after elective peripheral surgery. The effect of clonidine on intra‐operative haemodynamics (blood pressure and heart rate) during the first 30 min after induction and on the postoperative sedation of the patient was also investigated. Two hundred and eighty male ASA 1 and 2 patients, undergoing elective peripheral surgery were randomly administered either placebo or clonidine 2 μg.kg‐1 intravenously over 10 min after induction of anaesthesia. Clonidine was found to reduce the total incidence (p = 0.024), the severity (p = 0.005) and the duration (p= 0.01) of postoperative shivering. Clonidine did not increase postoperative sedation or diminish overall consciousness. We conclude that administration of clonidine 2 μg.kg‐1 intravenously after induction of anaesthesia is safe and reduces postoperative shivering in this group of patients.

Propofol-nitrous oxide versus thiopental sodium-isoflurane-nitrous oxide for strabismus surgery in children

STUDY OBJECTIVES To assess the quality of anesthesia and recovery and the frequency of postanesthetic retching and vomiting with propofol anesthesia for pediatric strabismus surgery. DESIGN Randomized, open, prospective study. SETTING University hospital. PATIENTS Forty children scheduled for strabismus surgery. INTERVENTIONS The 40 patients were all premedicated with oral midazolam and received intraoperative opioids. They were divided into two groups: Twenty children received propofol at induction, followed by maintenance of anesthesia with propofol infusion and an oxygen-nitrous oxide (O2-N2O) mixture. The other 20 children received thiopental sodium at induction, followed by isoflurane in an O2-N2O mixture. MEASUREMENTS AND MAIN RESULTS At induction, pain and spontaneous movements were seen significantly more with propofol (11 of 20 vs. 0 of 20 for pain and 13 of 20 vs. 0 of 20 for spontaneous movements; p < 0.001), whereas thoracic rigidity was observed only with thiopental sodium (4 of 20). During maintenance of anesthesia, significantly more oculocardiac reflexes were seen with propofol (10 of 20 vs. 3 of 20; p < 0.02). The interval between termination of anesthesia and extubation was significantly shorter with propofol (13 minutes vs. 16 minutes; p < 0.02). For the first 24 hours after surgery, significantly less retching and vomiting were observed in the propofol group (4 of 20 vs. 11 of 20; p = 0.02). CONCLUSIONS Propofol induction and maintenance of anesthesia for strabismus surgery in children significantly lowers the frequency of postanesthetic retching and vomiting, but propofol is associated with pain and spontaneous movements at induction and a high frequency of oculocardiac reflexes during maintenance infusion.

Pathogenesis CO2 Pneumoperitoneum-Induced Metabolic Hypoxemia in a Rabbit Model

STUDY OBJECTIVE To investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum-induced changes in blood gases, acid-base balance, and oxygen homeostasis in rabbits. DESIGN Prospective, randomized, controlled study (Canadian Task Force classification I). SETTING University training and teaching center. SUBJECTS Twenty-six adult female New Zealand white rabbits. INTERVENTION Anesthesia and pneumoperitoneum. MEASUREMENTS AND MAIN RESULTS In anesthetized rabbits arterial blood gases, acid-base balance, oxygenation values, and lactate concentrations were assayed during 2 hours. Spontaneous breathing, superficial and optimal ventilation without pneumoperitoneum, and with pneumoperitoneum at low (6 mm Hg) and higher (10 mm Hg) insufflation pressures were compared. The CO(2) pneumoperitoneum profoundly affected blood gases, acid-base balance, and oxygen homeostasis. Carboxemia with increasing end-tidal CO(2) and partial pressure of CO(2) (p <0.001), acidosis with decreasing pH (p <0.001), and base deficiency with decreasing actual base excess (p <0.001), standard base excess and standard bicarbonate and acid excess with increasing hydrogen bicarbonate (p <0.05 and <0.01) were found. Desaturation (p <0.01) with decreasing oxyhemoglobin p <0.05) and hemoglobin oxygen affinity (p <0.01) were also found. Carboxemia with acidosis was more pronounced with higher (p <0.01) than with lower (p >0.05) intraperitoneal pressures, and also with spontaneous breathing (p <0.05) and superficial ventilation (p <0.001) than with optimal ventilation, resulting in metabolic hypoxemia. CONCLUSION In superficially ventilated and spontaneously breathing rabbits, CO(2) pneumoperitoneum profoundly affected blood gases, acid-base balance, and oxygen homeostasis, resulting in metabolic hypoxemia. With optimal ventilation and low intraperitoneal pressure carboxemia, respiratory acidosis, and changes in oxygen metabolism were minimal.

Reduction of CO2‐pneumoperitoneum‐induced metabolic hypoxaemia by the addition of small amounts of O2 to the CO2 in a rabbit ventilated model. A preliminary study

BACKGROUND CO(2)-pneumoperitoneum used in endoscopic surgery induces system effects by CO(2) absorption. This study investigated the effect of the addition of O(2) to CO(2)-pneumoperitoneum, upon CO(2) absorption. METHODS The effect of a pneumoperitoneum using 100% CO(2) or 94% CO(2) + 6% O(2) upon arterial blood gases, acid base and O(2) homeostasis was evaluated. In series A suboptimal ventilation and a pneumoperitoneum pressure (PP) of 10 mmHg was used. In series B adequate ventilation and PP of 6 mmHg was used. RESULTS CO(2)-pneumoperitoneum profoundly affected blood gases and acid base homeostasis i.e. increasing pCO(2), HCO(3)(P < 0.001) and lactate concentrations (P < 0.05) and decreasing pH, actual base excess and standard bicarbonate (P < 0.001), resulting in metabolic hypoxaemia with desaturation, lower pO(2) (P < 0.001) and O(2)Hb (P < 0.05). These effects were more pronounced with higher PP and suboptimal ventilation. CONCLUSION CO(2)-pneumoperitoneum profoundly affected blood gases and acid base homeostasis resulting in metabolic hypoxaemia. The addition of 6% of O(2) to the CO(2)-pneumoperitoneum prevented these effects to a large extent. If these preliminary data are confirmed in the human, the addition of a few percent of O(2) to CO(2) could become important for endoscopic surgery of long duration, especially in obese patients with limited cardiorespiratory adaptation and steep Trendelenburg.

Lower limb compartment syndrome as a complication of laparoscopic laser surgery for severe endometriosis.

OBJECTIVE To report a case of lower limb compartment syndrome (LLCS) during long duration laparoscopic interventions for resection of extensive endometriosis, and evaluate the efficiency of a novel patient positioning method to reduce its prevalence. DESIGN Case report and observational study. SETTING University Hospitals, Belgium. PATIENT(S) Thirty-year-old woman undergoing a long duration laparoscopic intervention for resection of stage IV pelvic endometriosis. INTERVENTION(S) Laparoscopic intervention for resection of stage IV pelvic endometriosis. MAIN OUTCOME MEASURE(S) The occurrence of LLCS after laparoscopic surgery for extensive endometriosis, in this case, and the prevention of subsequent LLCS after the application of a novel patient positioning method including the following steps: maximal avoidance of the lithotomy position, patient positioning in a modified supine position, mobilization of the legs of the patient in between different surgical phases, and application of intermittent compression stockings. RESULT(S) The prevalence of lower limb compartment syndrome has been reduced to 0 since the application of the new patient positioning method. CONCLUSION(S) Lower limb compartment syndrome can be prevented in patients undergoing long duration multidisciplinary laparoscopic resection of extensive endometriosis by a novel sequential positioning method of patients before and during surgery.

Comparison of intramuscular buprenorphine and a buprenorphine/naloxone combination in the treatment of post-operative pain.

The analgesic efficacy and tolerance of a single intramuscular injection of either buprenorphine (0.3 mg) or a buprenorphine (0.3 mg)/naloxone (0.2 mg) combination was compared in 70 patients suffering from moderate to severe pain after abdominal surgery. Patients in both treatment groups experienced good analgesia which was apparent within 10 minutes of administration and lasted for approximately 12 hours. The most frequently reported unwanted effects were drowsiness and/or sleepiness and nausea and/or vomiting which were of mild or moderate severity in most cases. No significant differences were seen between the two treatment groups with regard to the overall assessments of efficacy and tolerance.

Effects of adding small amounts of oxygen to a carbon dioxide-pneumoperitoneum of increasing pressure in rabbit ventilation models

OBJECTIVE To evaluate the metabolic consequences of the addition of oxygen to the CO(2)-pneumoperitoneum. DESIGN Prospective randomized study in rabbits. After 30 minutes of ventilation pneumoperitoneum was maintained for 90 minutes with pure CO(2) or CO(2) with 2% or 6% of oxygen. The intraperitoneal pressure was increased from 10 to 15 and 20 mm Hg every 30 minutes. Ventilation rate was either fixed or a progressive hyperventilation. End points were changes in arterial blood gases (Pco(2), Po(2)), pH, acid-base balance (actual base excess [ABE], standard bicarbonate [SBC], standard base excess [SBE], hydrogen carbonate [HCO(3)(-)], concentration of total carbon dioxide [Tco(2)]); oxygen and oximetry (oxyhemoglobin [O(2)Hb], oxygen saturation [So(2)], reduced hemoglobin [RHb], total oxygen concentration [To(2)], and oxygen tension at half saturation assessing hemoglobin oxygen affinity [p50]); and lactate concentrations assayed every 15 minutes. SETTING University research center. ANIMALS Twenty-four adult female New Zealand white rabbits. INTERVENTION(S) Anesthesia, mechanical ventilation, and pneumoperitoneum. RESULT(S) The effects of CO(2)-pneumoperitoneum on all end points increased with the elevated intraperitoneal pressure and were more pronounced when ventilation was fixed. Changes were less when 2% or 6% of oxygen had been added to the CO(2)-pneumoperitoneum. With use of logistic regression, the addition of oxygen, intraperitoneal pressure, and ventilation were found to be independent variables affecting Pco(2), pH, ABE, SBE, HCO(3)(-), O(2)Hb, So(2), p50, and end-tidal CO(2). CONCLUSION(S) The metabolic consequences of the combined effect of increased intraperitoneal pressure and CO(2)-pneumoperitoneum were less when 2% to 6% of oxygen was added or when animals were hyperventilated. We suggest that metabolic and mesothelial hypoxemia caused by CO(2) absorption can be reduced by adding small amounts of oxygen and by hyperventilation.

A systematic review and meta-regression analysis of mivacurium for tracheal intubation

We systematically reviewed factors associated with intubation conditions in randomised controlled trials of mivacurium, using random‐effects meta‐regression analysis. We included 29 studies of 1050 healthy participants. Four factors explained 72.9% of the variation in the probability of excellent intubation conditions: mivacurium dose, 24.4%; opioid use, 29.9%; time to intubation and age together, 18.6%. The odds ratio (95% CI) for excellent intubation was 3.14 (1.65–5.73) for doubling the mivacurium dose, 5.99 (2.14–15.18) for adding opioids to the intubation sequence, and 6.55 (6.01–7.74) for increasing the delay between mivacurium injection and airway insertion from 1 to 2 min in subjects aged 25 years and 2.17 (2.01–2.69) for subjects aged 70 years, p < 0.001 for all. We conclude that good conditions for tracheal intubation are more likely by delaying laryngoscopy after injecting a higher dose of mivacurium with an opioid, particularly in older people.