Hugo Van Aken

Long-chain triglycerides improve recovery from myocardial stunning in conscious dogs.

OBJECTIVESnFree fatty acid (FFA) oxidation is depressed in the postischaemic stunned myocardium and recovers in parallel with the normalization of contractile performance. Assuming a causal role for this metabolic disturbance in the pathogenesis of stunning, we questioned whether exogenous administration of high dose triglycerides during reperfusion of postischaemic myocardium, could improve its functional recovery.nnnMETHODSnThirteen dogs were chronically instrumented to measure global and regional haemodynamics and to produce a 10 min episode of regional myocardial ischaemia. In 7 dogs, Intralipid 20% was administered i.v. during the reperfusion phase. Contractile recovery of stunned myocardium was compared with control saline treatments. The series were repeated in another 6 animals, but oxfenicine (CPT I inhibitor) preceeded Intralipid during reperfusion.nnnRESULTSnContractile recovery of stunned myocardium was faster and more extensive when Intralipid was administered during reperfusion than with saline treatment (wall thickening fraction 86 +/- 6% of preischaemic controls versus 52 +/- 11% at 90 min post-reperfusion; P < 0.05). Oxfenicine pretreatment completely abolished this beneficial effect.nnnCONCLUSIONSnExogenous administration of triglycerides during reperfusion of postischaemic myocardium improves functional recovery from stunning. This beneficial effect most likely operates through enhanced FFA availability and/or oxidation since it could be abolished by selective inhibition of the carnitine palmitoyl I enzyme.

Light anaesthesia with propofol for paediatric MRI

Anaesthetic techniques and monitoring equipment may interfere with the technical demands of magnetic resonance imaging. The purpose of this study was to evaluate the safety and efficacy of a light anaesthetic technique with intravenous propofol in nonintubated children. In 20 neuropaediatric patients sedation was induced with propofol 1 mg.kg−1, followed by a continuous infusion titrated to produce adequate immobilisation. Oxygen, 4 l.min−1, was administrated by paediatric face mask. Respiratory rate, end‐tidal carbon dioxide tension and oxygen saturation were continuously monitored. In 10 patients capillary blood gas tensions were determined 3 and 20 min after the procedure. Data are reported as mean (SD) and the mean (SD) total propofol dose was 5 (2) mg.kg−1.h−1. Oxygen saturation remained constantly higher than 96% in all patients. End‐tidal carbon dioxide tension varied between 35 (7) mmHg 3 min after induction, and 41 (6) mmHg 30 min after the start of the procedure. End‐tidal to capillary PCO2 difference was 4 (3) mmHg. Within 20 min after the end of the procedure all patients were fit for dismissal to the ward. One imaging sequence out of 49 was repeated because of movement artefacts. In conclusion, intravenous propofol sedation appears to be a safe and reliable technique for paediatric sedation during magnetic resonance imaging.

Propofol does not inhibit hypoxic pulmonary vasoconstriction in humans

The influence of increasing doses of propofol (from 6 to 12 mg/kg/h by continuous infusion) on hypoxic pulmonary vasoconstriction was studied in 10 patients prior to thoracic surgery. All patients were intubated with a left-sided double-lumen endobronchial tube. Initial anesthesia and muscle relaxation were accomplished by administering fentanyl, droperidol, and pancuronium. After 100% oxygen ventilation of both lungs for 20 min in a lateral decubitus position, the nondependent lung was deflated and one-lung ventilation was started. The dependent lung was continuously ventilated with 100% oxygen. Twenty minutes after the start of one-lung ventilation, propofol at an IV infusion rate of 6 mg/kg/h was added to the anesthetic technique. Thirty minutes later it was increased to 10 mg/kg/h and another 15 min later to 12 mg/kg/h. Then the propofol infusion was stopped. Thirty minutes later, two-lung ventilation was restarted to compare initial values. No changes in venous admixture or PaO2 were observed during propofol infusion. There was no change in any respiratory or circulatory variables except systemic vascular resistance, which decreased significantly immediately after the propofol infusion commenced but returned to control values 15 min later for the rest of the observation period. After reestablishing two-lung ventilation, all variables did not differ from control values. In all patients, the hypoxic pulmonary vasoconstriction reflex was present after institution of one-lung ventilation and was not abolished after administration of propofol in doses from 6 to 12 mg/kg/h.

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

STUDY OBJECTIVESnTo assess the quality of anesthesia and recovery and the frequency of postanesthetic retching and vomiting with propofol anesthesia for pediatric strabismus surgery.nnnDESIGNnRandomized, open, prospective study.nnnSETTINGnUniversity hospital.nnnPATIENTSnForty children scheduled for strabismus surgery.nnnINTERVENTIONSnThe 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.nnnMEASUREMENTS AND MAIN RESULTSnAt 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).nnnCONCLUSIONSnPropofol 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.

Anesthesia for craniotomy: Total intravenous anesthesia with propofol and alfentanil compared to anesthesia with thiopental sodium, isoflurane, fentanyl, and nitrous oxide

STUDY OBJECTIVEnTo compare a total intravenous (IV) anesthetic technique based on propofol and alfentanil with a commonly used anesthetic technique for craniotomy.nnnDESIGNnOpen-label, randomized, clinical study.nnnSETTINGnNeurosurgical clinic at a university hospital.nnnPATIENTSnForty patients, aged 18 to 55 years, scheduled for brain tumor surgery.nnnINTERVENTIONSnIn 20 patients, anesthesia was induced with fentanyl and thiopental sodium and maintained with fentanyl, dehydrobenzperidol, isoflurane, nitrous oxide (N2O), and a thiopental sodium infusion. Twenty patients were anesthetized with a propofol loading infusion followed by a maintenance infusion at a fixed rate. In addition, alfentanil was administered as a loading bolus, followed by a variable-rate infusion, with additional doses as necessary to maintain hemodynamic stability.nnnMEASUREMENTS AND MAIN RESULTSnA decrease in blood pressure (BP) after induction with thiopental sodium was followed by a significant increase in BP and heart rate (HR) during intubation. BP and HR did not change during the propofol loading infusion. However, the administration of alfentanil was followed by a similar decrease in BP with a return to baseline values during the intubation period. Return of normal orientation (7 +/- 5 minutes vs 27 +/- 23 minutes) and concentration (12 +/- 12 minutes vs 35 +/- 37 minutes) was shorter and more predictable for the propofol-alfentanil-treated patients than for the thiopental sodium patients. Maintenance propofol concentration (nine patients) was between 3 +/- 0.69 micrograms/ml and 3.36 +/- 1.17 micrograms/ml, while the concentration at awakening was 1.09 microgram/ml. Alfentanil concentration at extubation (nine patients) was 79 +/- 34 ng/ml.nnnCONCLUSIONnA total IV anesthetic technique with propofol and alfentanil is a valuable alternative to a more commonly used technique based on thiopental sodium, N2O, fentanyl, and isoflurane.

Maternal and neonatal effects of adding epidural sufentanil to 0.5% bupivacaine for cesarean delivery

STUDY OBJECTIVEnTo determine the maternal and fetal effects of the addition of epidural sufentanil to 0.5% bupivacaine for cesarean delivery.nnnDESIGNnRandomized, double-blind, prospective study.nnnSETTINGnUniversity Hospitals, Katholieke Universiteit Leuven, Leuven, Belgium.nnnPATIENTSnSixty women at term scheduled for elective cesarean section, all of whom had elected epidural anesthesia.nnnINTERVENTIONSnThe 60 women were divided into three groups of 20, with each group receiving a different 1 ml study solution: saline (control) or sufentanil 20 micrograms or sufentanil 30 micrograms added to 0.5% bupivacaine and epinephrine (1:200,000).nnnMEASUREMENTS AND MAIN RESULTSnIn the mother, the quality of anesthesia, the duration of postoperative analgesia, the volume of anesthetic, and the frequency of side effects were examined. The neonates were evaluated at 5 and 10 minutes after birth by Apgar scores and between 60 and 120 minutes after birth by both the screening test developed by Prechtl and the Neurological and Adaptive Capacity Scoring System. Immediately after delivery, maternal and umbilical vein blood were drawn and assayed for sufentanil levels. Adding sufentanil significantly improved the quality of anesthesia without depressing the neurobehavioral status of the baby.nnnCONCLUSIONnThe epidural injection of sufentanil added to 0.5% bupivacaine with epinephrine improved the quality of anesthesia during elective cesarean section without jeopardizing the safety of the baby.

Comparison of the addition of three different doses of sufentanil to 0.125% bupivacaine given epidurally during labour

In a double‐blind, randomised, prospective study 150 women in labour received intermittent epidural injections of 10 ml 0.125% bupivacaine with adrenaline (1: 800000) with 5, 7.5 or 10 μg of sufentanil added. The onset, duration, and quality of analgesia were compared. Motor block, type of delivery and neonatal Apgar scores were noted. The onset, duration, and quality of analgesia were generally similar in the three groups, except following the second injection when the quality of analgesia was significantly superior in the sufentanil 7.5 and 10 μg groups. Motor blockade and type of delivery did not differ between the groups and there were no differences in neonatal Apgar scores. No patient required more than three injections. We conclude that 7.5 μg sufentanil is the optimal dose to add to intermittent epidural injections of 10 ml 0.125% bupivacaine with adrenaline (1: 800000) for pain relief in labour.

Labor pain relief using bupivacaine and sufentanil: Patient controlled epidural analgesia versus intermittent injections

OBJECTIVESnTo determine whether the use of patient-controlled epidural analgesia (PCEA) versus intermittent injections (CIT) resulted in local anesthetic dose reduction.nnnSTUDY DESIGNnPCEA and CIT using a mixture of 0.125% bupivacaine with sufentanil 1 or 0.75 microgram/ml were compared in 60 and 195 parturients, respectively. Assessments included pain scores, local anesthetic consumption, degree of motor blockade, type of delivery and neonatal outcome. Statistical analysis was done using Students t test and Chi-squares.nnnRESULTSnPCEA and CIT provided effective analgesia during labor and delivery. A higher dose of opioid significantly reduced the use of local anesthetic solution in PCEA-patients. There was no difference in motor blockade, type of delivery and neonatal outcome.nnnCONCLUSIONnPatient-controlled epidural analgesia is an effective, safe and acceptable alternative to conventional intermittent epidural injections for pain relief during labor and delivery.

Interaction of antibiotics on pipecuronium-induced neuromuscular blockade

STUDY OBJECTIVEnTo measure the interaction of two antibiotics (clindamycin and colistin) on neuromuscular blockade induced by pipecuronium bromide (a new long-acting, steroidal, nondepolarizing neuromuscular blocking drug).nnnDESIGNnProspective, randomized, placebo-controlled study.nnnSETTINGnInpatient gynecologic and gastroenterologic service at a university medical center.nnnPATIENTSnThree groups of 20 ASA physical status I and II patients with normal kidney and liver function, taking no medication, and undergoing elective surgery under general anesthesia.nnnINTERVENTIONSnAnesthesia was induced with propofol and alfentanil intravenously (IV) and maintained with a propofol infusion and 60% nitrous oxide in oxygen. Pipecuronium bromide 50 micrograms/kg was administered after reaching a stable baseline of single-twitch response. At 25% recovery of pipecuronium-induced neuromuscular blockade, patients received one of two antibiotics, clindamycin 300 mg or colistin 1 million IU, or a placebo.nnnMEASUREMENTS AND MAIN RESULTSnThe recovery index (RI, defined as time from 25% to 75% recovery of neuromuscular blockade) was measured using the single-twitch response of the adductor pollicis muscle with supramaximal stimulation of the ulnar nerve at the wrist. RI after administration of an antibiotic (given at 25% recovery) was measured and compared with RI of the control group using Students unpaired t-test. Statistical analyses of the results showed a significant prolongation of the recovery time (from 25% to 75% recovery) of 40 minutes for colistin.nnnCONCLUSIONSnWhen this type of antibiotic is used during anesthesia with pipercuronium as a muscle relaxant, one must be aware of a significant prolongation of an already long-acting neuromuscular blockade and (although not observed in this study) possible problems in antagonism.

4 Paracetamol and propacetamol for post-operative pain: contrasts to traditional NSAIDs

Summary Although less efficacious than opioid compounds, parenterally administered NSAID and paracetamol are effective analgesics that have a clear role in the management of post-operative pain. They should be considered as part of a balanced approach to analgesia using a combination of different drugs and techniques. Pain therapy should be structured. Assessment of pain allows the finding of appropriate measures of treatment. The first step of the ‘analgesic treatment ladder’ is represented by paracetamol/NSAIDs (mild analgesics) which are the first line drugs for control of mild to moderate pain. The second step of the ‘analgesic treatment ladder’ for the control of more severe pain includes the combination of these drugs with opioids. Paracetamol/NSAIDs have fewer side effects than opioids and by combination of both groups a lower dose of opioids can be administered (opioid sparing). A third step of the ‘analgesic treatment ladder’ might be necessary for patients with severe pain. This step includes the use of local anaesthetics and other adjuvant medications that can improve the pain treatment ( Kehlet and Dahl, 1993 ). Paracetamol and NSAIDs, are indicated for the treatment of mild to moderate pain and for more severe pain, in combination with opioids, local anaesthetics and other adjuvant medications. If a patient presents risk factors for NSAIDs-induced adverse events, today it is recommended to achieve the regular background analgesia with paracetamol alone. In the future, a more selective use of NSAIDs will provide more advantages. For this reason, more research is required to distinguish the differences between the various NSAIDs concerning efficacy, tolerability, incidence of adverse effects, optimal route of administration and dosage schedules. Today, the optimal regimen for the peri-operative management of pain would appear to involve primarily paracetamol, the selective use of NSAIDs in low-risk patients in combination with opioid analgesics and local anaesthetics whenever necessary.