Pierre-Yves Dewandre

Effect of intra-operative magnesium sulphate on pain relief and patient comfort after major lumbar orthopaedic surgery

Summary The effects of intra‐operative magnesium sulphate on pain relief after major lumbar surgery were investigated in 24 patients. Patients were randomly allocated to receive either an infusion of 50 mg.kg−1 magnesium sulphate or an equivalent volume of saline at induction of anaesthesia. Anaesthesia was induced with propofol and remifentanil. Tracheal intubation was facilitated using rocuronium. Maintenance was achieved with remifentanil and sevoflurane in nitrous oxide/ oxygen. Intra‐operative monitoring included standard equipment and neuromuscular transmission. During surgery, neuromuscular block recovery was longer in the magnesium group. Postoperative opioid consumption and pain scores were lower in the magnesium group. The first nights sleep and the global satisfaction scores were better in the magnesium group. The results of the study support magnesium sulphate as a useful adjuvant for postoperative analgesia after major lumbar surgery.

Influence of induction of anaesthesia on intubating conditions one minute after rocuronium administration: comparison of ketamine and thiopentone

We compared the effect of thiopentone and ketamine on intubating conditions after rocuronium 0.6 mgkg−1 in two groups of patients (n = 16 each), aged 21–44 years, undergoing elective surgery. Premedication consisted of alprazolam 1 mg by mouth 1 h before surgery. All patients received midazolam 2 mg intravenously 2 min before intravenous administration of thiopentone 5 mgkg−1 or ketamine 2.5 mgkg−1. Muscle relaxation was provided by rocuronium 0.6 mgkg−1. One minute after rocuronium administration, tracheal intubation was performed within 15 s by a skilled anaesthetist blinded to the treatment group assignment. Intubating conditions were graded as excellent, good, fair or poor on the basis of jaw relaxation, position of vocal cords and diaphragmatic response. Neuromuscular transmission was assessed at the adductor pollicis muscle using a TOF‐GUARD™ monitor. Excellent and good intubating conditions were obtained in 100% of patients in the ketamine group and in 50% of patients in the thiopentone group (p = 0.002). Jaw relaxation was similar in both groups but vocal cord conditions were better and the diaphragmatic response less marked in the ketamine group compared with the thiopentone group (p = 0.002). The degree of neuromuscular block [% decrease of T1, mean (SD)] at the time of intubation was similar: 51.8 (25)% (ketamine group) and 54.3 (23.1)% (thiopentone group). We conclude that ketamine 2.5  mgkg−1 provides better intubating conditions than thiopentone 5 mgkg−1 1 min after administration of rocuronium 0.6 mgkg−1.

Bispectral index profile during carotid cross clamping.

This study aimed at investigating the Bispectral Index (BIS) profile during carotid cross clamping (CXC). The study involved a pilot group of 10 patients undergoing routine carotid endarterectomy with shunt insertion under total intravenous anesthesia, and a study group of 26 additional patients. In all patients, rates of propofol and remifentanil providing a steady-state level of hypnosis (BIS: 40-60) were maintained constant throughout a recording period ranging from 3 minutes before CXC to shunt insertion. BIS was recorded throughout this period and the internal carotid backflow observed at the time of shunt insertion was graded as good, moderate, or poor. In addition, A-Line Autoregressive Index (AAI) and processed electroencephalogram (EEG) parameters were recorded in patients of the study group. All parameters were averaged over 1 minute before CXC, at CXC, 1, 2, and 3 minutes after CXC, and at shunt insertion. Statistical analysis was performed using χ2, Friedman, and Spearman correlation tests. For technical reasons, reliable AAI, BIS monitor-derived, and other processed EEG data were obtained in 24, 25, and 18 patients of the study group, respectively. During the first 3 minutes after CXC, BIS increased over 60 [68.8 (6.1)] in 47%, decreased below 40 [34.9 (4.4)] in 25%, and remained in the 40 to 60 range in 28% of all recruited patients. A BIS increase was more frequently observed in patients with moderate or poor than in those with good internal carotid backflow (78, 67, and 29%, respectively). It was significantly correlated to an increase in AAI and EEG amplitude, a decrease in EEG suppression ratio, and a shorter time between induction of anesthesia and CXC. A BIS decrease was significantly correlated to an increase in suppression ratio and a longer time between induction and CXC. In conclusion, during CXC under a constant level of intravenous anesthesia, BIS may increase, decrease, or remain unchanged. The paradoxical BIS increase could be related to borderline ischemia, a change in brain anesthetic agent concentration, or a change in the nociceptive-antinociceptive balance associated with a CXC-elicited painful stimulation. Caution should be used when interpreting BIS value during CXC.

Effect of epidural bupivacaine on the relationship between the bispectral index and end‐expiratory concentrations of desflurane

We compared the relationship between the bispectral index and end‐tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or 10 ml bupivacaine 0.125% with epinephrine 1/800 000 (group B) before induction of anaesthesia with sufentanil (0.15 μg.kg−1) and propofol (2 mg.kg−1); muscle relaxation was obtained with cisatracurium (0.2 mg.kg−1). Patients lungs were ventilated to maintain end‐tidal desflurane at 3% in O2/N2O (50/50) until 5 min after skin incision, followed by two consecutive 10 min periods at end‐tidal desflurane 6% and 9%. bispectral index values were recorded before induction, at 3% desflurane before and 5 min after skin incision, and at 6% and 9% end‐tidal desflurane. Bispectral index decreased with increasing end‐tidal desflurane concentration (anova: p < 0.05). The decrease in bispectral index was significant between pre‐induction, 3% and 6% desflurane. No significant difference was observed at 3% desflurane before and after skin incision, or between 6 and 9% desflurane. The relationship between bispectral index and end‐tidal desflurane concentration was fitted by a linear regression in each group. No significant difference in bispectral index was observed between the groups at any time. We conclude that bispectral index decreases with increasing desflurane concentration and that this relationship is not affected by epidural 0.125% bupivacaine.

Impact of the addition of sufentanil 5 μg or clonidine 75 μg on the minimum local analgesic concentration of ropivacaine for epidural analgesia in labour: a randomized comparison

BACKGROUND Addition of lipophilic opioids or alpha2-agonists to local anaesthetic solutions reduces local anaesthetic requirements and side effects. While the efficacy and side effects of these adjuvants are dose-related, information about their relative analgesic potencies is lacking, making it difficult to draw meaningful clinical conclusions. The aim of the present study was to assess the relative sparing of ropivacaine by clinically relevant doses of sufentanil and clonidine using the minimum local analgesic concentration (MLAC) model. METHODS In this prospective, double-blind study, the sparing effect of sufentanil 5 microg and clonidine 75 microg on the MLAC of ropivacaine administered for labour epidural analgesia was compared in 78 women at <5 cm cervical dilatation. Women were randomly allocated to one of three groups: plain ropivacaine, ropivacaine with sufentanil 5 microg and ropivacaine with clonidine 75 microg. RESULTS The MLAC of plain ropivacaine was 0.099% wt/vol (95%CI: 0.090 to 0.109) and was reduced to 0.036% wt/vol (95% CI: 0.024 to 0.049) when combined with sufentanil 5 microg and to 0.036% wt/vol (95% CI: 0.027 to 0.046) with clonidine 75 microg (P < 0.001). The wt/wt local anesthetic sparing potency ratio of sufentanil to clonidine was 15.1 (95% CI: 10.3 to 23.4). CONCLUSIONS Sufentanil 5 microg and clonidine 75 microg produce similar reductions in the MLAC of ropivacaine. This finding will make feasible the assessment of the side effects of these adjuvants administered at equipotent doses in further studies.

Side effects of the addition of clonidine 75 μg or sufentanil 5 μg to 0.2% ropivacaine for labour epidural analgesia

BACKGROUND Sufentanil 5 microg and clonidine 75 microg produce a similar reduction in minimum local anaesthetic concentration of ropivacaine. The aim of the present study was to compare the side effects of two equianalgesic solutions by combining 0.2% ropivacaine with either sufentanil 5 microg or clonidine 75 microg for labour epidural analgesia. METHODS In a prospective double-blind study, 60 women at 5 cm cervical dilatation were randomly allocated to receive 0.2% ropivacaine with either sufentanil 5 microg or clonidine 75 microg to initiate labour analgesia. The analgesic efficacy and side effects of the two mixtures were compared. RESULTS Onset, duration and quality of analgesia and subsequent ropivacaine consumption were similar in the two groups. Hypotension was significantly more frequent and severe with clonidine than with sufentanil (systolic blood pressure <100 mmHg: 17/26 vs. 6/24, P <0.05; systolic blood pressure <90 mmHg: 5/26 vs. 0/24, P <0.05) resulting in more frequent ephedrine administration (11/26 vs. 2/24, P <0.05) and larger fluid requirements (1696 +/- 583 mL vs. 1264 +/- 407 mL, P < 0.05). Conversely, pruritus was more frequent with sufentanil than with clonidine (6/26 vs. 1/24, P <0.05). CONCLUSIONS Hypotension occurs more frequently when clonidine is added to epidural ropivacaine instead of an equianalgesic dose of sufentanil. Therefore, clonidine cannot be recommended for routine administration for labour epidural analgesia.

Management of severe preeclampsia

Abstract Features of severe preeclampsia include severe proteinuric hypertension and symptoms of central nervous system dysfunction, hepatocellular injury, thrombocytopenia, oliguria, pulmonary oedema, cerebrovascular accident and severe intrauterine growth restriction. Women with severe preeclampsia must be hospitalized to confirm the diagnosis, to assess the severity of the disease, to monitor the progression of the disease and to try to stabilize the disease. Severe preeclampsia may be managed expectantly, in selected cases. The objective of expectant management in these patients is to improve neonatal outcome. Expectant management is based on antihypertensive treatment and prevention of end organ dysfunction. Antihypertensive treatment improves maternal outcome but has the potential to be deleterious for the foetus. Plasma volume expansion has been suggested for severe preeclampsia but trials failed to show any benefit. Magnesium sulfate is the anticonvulsivant of choice to treat or prevent eclampsia when indicated. Antenatal corticosteroids are recommended in severely preeclamptic women with 26-34 weeks gestation. Timing of delivery is based upon gestational age, severity of preeclampsia, maternal and foetal risks.

Analgésie épidurale obstétricale et pseudoxanthome élastique : à propos d’un cas

Pseudoxanthoma elasticum is a rare inherited disorder of the elastic tissue characterised by multisystem manifestations. Skin, eyes, gastro-intestinal system and cardiovascular system are the major affected systems. We describe the anaesthetic management of a parturient affected by this disease.