Is magnesium sulfate by the intrathecal route efficient and safe?

The polypharmacological approach to the treatment of postoperative pain has become routine in an attempt to minimize the adverse side effects of opioids. Magnesium sulphate is a noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptor and thus can modify nociceptive modulation. Intravenous administration of magnesium sulphate can improve postoperative analgesia and decrease the requirement for postoperative opiates, but the effects are inconsistent and have not been reliably accompanied by a reduction in the incidence of morphine-related adverse events. Several studies have shown that the administration of magnesium by the intrathecal route is safe and, in combination with opiates, extends the effect of spinal anaesthesia in both animal and human studies. The analysis of these studies justifies further investigation of the use of magnesium sulphate by the intrathecal route.

The effect of adding intrathecal magnesium sulphate to morphine-fentanyl spinal analgesia after thoracic surgery. A prospective, double-blind, placebo-controlled research study.

BACKGROUND: We investigated whether intrathecally magnesium sulphate added to morphine and fentanyl reduces patients' postoperative analgesia requirements and prolongs spinal opioid analgesia after thoracotomy. METHODS: In a single-center, prospective, placebo-controlled, double-blind trial, we enrolled 58 adult patients undergoing elective posterolateral thoracotomy. Patients were randomized to receive either 25 µg of fentanyl citrate (0.5 mL)+300 µg of morphine+1.0 mL of preservative-free 0.9% sodium chloride (Group S) or 25 µg of fentanyl citrate (0.5 mL)+300 µg of morphine+50mg of magnesium sulphate 5% (1.0 mL) (Group MgSO(4)) for intrathecal analgesia. Opioid consumption and postoperative pain were assessed for 36 hours. RESULTS: VAS pain scores at rest and on coughing were similar in all groups. The total 36-h intravenous morphine requirements were significantly lower in group MgSO(4) (14 [9.50-26.50] mg vs. 33 [30-41] mg, p<0.001); i.e. 57% less for the group MgSO(4). The total dose of intravenous morphine administered during titration was significantly lower in this group (4 [2-8] mg vs. 8 [6-10] mg, p=0.001). Morphine consumption was significantly lower in the group MgSO(4) at intervals 0-12, 12-24 and 24-36 h. The number of patients requiring titration was significantly lower in group MgSO(4) (68% vs. 96%, p=0.001). There is no difference in opioid side effects. No patient experienced side effects resulting from lumbar puncture, or neurological deficit or signs of systemic magnesium toxicity. CONCLUSION: We found that in patients undergoing pulmonary resection with elective posterolateral thoracotomy, magnesium sulphate (50mg), when added to spinal morphine analgesia reduces postoperative morphine requirements, the number of patients requiring morphine titration without increasing opioid side effects.

A prospective, randomised comparison of continuous paravertebral block and continuous intercostal nerve block for post-thoracotomy pain

ABSTRACTBackground: This study aimed to compare paravertebral block and continuous intercostal nerve block after thoracotomy.Methods: Forty-six adult patients undergoing elective posterolateral thoracotomy were randomised to receive either acontinuous intercostal nerve blockade or a paravertebral block. Opioid consumption and postoperative pain were assessedfor 48 hours .Pulmonary function was assessed by forced expiratory volume in 1 s (FEV1) recorded at 4 hours intervals.Results: With respect to the objective visual assessment (VAS), both techniques were effective for post thoracotomy pain.The average VAS score at rest was 29±10mm for paravertebral block and 31.5±11mm for continuous intercostal nerve block.The average VAS score on coughing was 36±14mm for the first one and 4 ±14mm for the second group.Pain at rest was similar in both groups. Pain scores on coughing were lower in paravertebral block group at 42 and 48hours. Post-thoracotomy function was better preserved with paravertebral block. No difference was found among the twogroups for side effects related to technique, major morbidity or duration of hospitalisation.Conclusion: We found that continuous intercostal nerve block and paravertebral block were effective and safe methods forpost-thoracotomy pain

Combined spinal-epidural analgesia in labor--comparison of sufentanil vs tramadol.

BACKGROUND: Combined spinal-epidural (CSE) analgesia is becoming increasingly used to provide pain relief during labor. It combines both the rapid onset of the spinal analgesia and the flexibility of the epidural catheter. Intrathecal sufentanil provides rapid-onset and profound analgesia during the first stage of labor. The dose required to produce this effect can be associated with maternal respiratory depression, hypotension, nausea, or pruritus. The major concern of the anesthesiologist is to limit these side effects sources of discomfort to a parturient, by choosing the optimal dose of sufentanil or searching for an alternative. The purpose of this study is to compare tramadol and sufentanil used in CSE analgesia in terms of duration of analgesia and frequency of adverse maternal or fetal effects. METHODS: Forty parturients requesting labor analgesia were included in this prospective study. In a combined spinal- epidural technique, at 3 to 4 cm cervical dilation, patients were randomly assigned to receive either one of the following intrathecal solutions: 2.5 mg sufentanil (n = 20) and 2.5 mg bupivacaine, or 25 mg tramadol (n = 20) and 2.5 mg bupivacaine. Visual analog scores for pain, blood pressure, heart rate, sensory levels, incidence of nausea and pruritus, motor blockade, and maternal satisfaction, were recorded. RESULTS: Patients receiving 25 mg intrathecal tramadol with 2.5 mg bupivacaine had significantly longer-lasting analgesia (114 +/- 7 min). than those receiving 2.5 mg intrathecal sufentanil and 2.5 mg bupivacaine (54 +/- 11 min). No adverse maternal or fetal effects were noted in the group sufentanil. Five parturients of the tramadol group, presented vomiting 10 min after induction. There was no difference in the time from analgesia to delivery, incidence of operative or assisted delivery or cervical dilation. During labor, maternal satisfaction was good. CONCLUSIONS: 2.5 micrograms of intrathecal sufentanil combined with 2.5 mg bupivacaine provides rapid-onset and profound analgesia during the first stage of labor without adverse maternal or fetal effects. 25 mg intrathecal tramadol with 2.5 mg bupivacaine had longer-lasting analgesia. The major side effect was vomiting.

[The prone position in acute respiratory distress syndrome: a critical systematic review]. / Le décubitus ventral au cours du syndrome de détresse respiratoire aiguë: une revue critique de la littérature.

OBJECTIVE: To do a critical systematic review regarding effects of prone positioning (PP) in patients with acute respiratory distress syndrome (ARDS). METHODS: A systematic review (Highwire, Medline, Cochrane Library from 1976 to 2004), using the keywords: prone position, acute respiratory distress syndrome, allowed us to include the human studies on PP in ARDS patients, independantly of their objectives or their type of protocol. To appreciate the studies validity, we scored the quality evidence of the studies in order to grade our conclusions. RESULTS AND CONCLUSION: The qualitative analysis of the 58 included studies (1,500 patients returned prone, 4,000 episodes of PP) led to the following main conclusions: 1) the PP improves oxygenation in the majority of ARDS patients (level of evidence I); 2) the PP improves the pulmonary haemodynamics without altering the systemic haemodynamics (level of evidence III); 3) the PP enhances the recruitment maneuvers (level of evidence III); 4) because there are no formal predictive criteria for response to the PP, a "trial of PP" or better two PP trials are necessary to look for the responders; 5) the PP should be performed as early as possible in the course of severe ARDS; 6) the optimal duration of PP is 18 to 23 hours daily, and it should be continued until improvement of arterial oxygenation, or loss of the positive effect of PP on arterial oxygenation or evidently patient's death.