Martin Rosenblum

Activation of the Bezold-Jarisch reflex in the sitting position for shoulder arthroscopy using interscalene block.

A retrospective analysis of 116 patients who underwent shoulder arthroscopy in the sitting position with interscalene block (ISB) revealed 20 patients who experienced potentially dangerous vasovagal events characterized by sudden severe hypotension and bradycardia (Group 1).The event occurred 61 +/- 18 min after the block placement. Ninety-six patients (Group 2) did not experience a vasovagal event. Of the patients in Group 2, 18 received beta-adrenergic blockers for increasing heart rate and/or arterial blood pressure (Group 2B) while 78 did not (Group 2A). The number receiving beta-adrenergic blockers was significantly greater than in Group 1 (18/96 vs 0/20, P < 0.05). There were no significant demographic or baseline hemodynamic differences between groups, but the beta-adrenergic blocker and vagal groups showed significantly greater intraoperative peak heart rates (P < 0.05). All patients received epinephrine in their local anesthetic for ISB, incision sites, and articular irrigating solution. Total and weight-corrected epinephrine doses differed significantly between groups (lowest in Group 2A, P < 0.01). Activation of the Bezold-Jarisch reflex, induced by increased circulating epinephrine levels and the sitting position, is the postulated mechanism. (Anesth Analg 1995;80:1158-62)

Ibuprofen provides longer lasting analgesia than fentanyl after laparoscopic surgery

The authors compared the analgesic efficacy of one dose of oral ibuprofen with that of intravenously administered fentanyl for relief of pain after outpatient laparoscopic surgery. Thirty healthy female patients received either 800 mg of oral ibuprofen preoperatively or 75 micrograms of intravenous fentanyl intraoperatively plus respective intravenous or oral placebos in a randomized, double-blind manner. Patients recorded their degree of pain and nausea in the recovery room, in the same-day surgery stepdown unit, during the ride home, and upon arrival at home. The postanesthesia care nurse recorded the amount of fentanyl and droperidol needed to treat pain and nausea in the recovery room. Patients who received ibuprofen were more comfortable in the stepdown unit (P less than 0.05) and after arrival home (P less than 0.05) than those in the fentanyl group. Additionally, patients who received ibuprofen had lower nausea scores in the step-down unit (P less than 0.05); this may have been related to the lower total fentanyl dose in these patients. The authors conclude that ibuprofen may be a useful alternative to fentanyl for providing postoperative analgesia for outpatient surgery.

Comparison of epidural and patient-controlled intravenous morphine following joint replacement surgery

The authors conducted a randomized, prospective study comparing epidural morphine with patient-controlled intravenous (iv) morphine in 30 patients recovering from total hip or total knee arthroplasty. Six, 18, and 24 hr postoperatively, patients useda 10 cm visual-analogue scale to indicate both their current degree of discomfort and the maximum discomfort they had experienced since the previous evaluation. Pain at the time of evaluation did not differ between patients receiving epidural (2.6 ± 0.4 cm, mean ± SEM) and patient-controlled iv morphine (3.4 ± 0.3 cm). However, patients who received epidural morphine recalled less pain during the period preceding evaluation (4.2 ± 0.5 cm) than did those receiving patient-controlled analgesia (5.5 ± 0.4 cm, P < 0.05). Patients receiving epidural morphine were more likely to require treatment for pruritus (4 of 15) than patients who received patient-controlled iv morphine (none of 15, P < 0.05). Minimum respiratory rates were lower in patients receiving epidural morphine (15.0 ± 0.3) than in those receiving patient-controlled analgesia (16.5 ± 0.4, P < 0.05), but no patients required treatment for respiratory depression. The authors conclude that epidural morphine may provide more consistent analgesia following joint replacement surgery than patient-controlled morphine; however, there is a higher incidence of side-effects with the epidural technique.RésuméLes auteurs ont procédé à une étude prospective, randomisée, comparant la morphine épidurale avec l’administration intraveineuse (iv) de morphine controlée par le patient, chez 30 patients ayant subi une arthroplastie totale de la hanche ou du genoux. Les patients ont utilisé une échelle visuelle analogue de 10 cm à 6, 18 et 24 heures dans la période postopératoire pour indiquer le degré d’inconfort à ce moment et le degré d’inconfort maximal ressenti depuis l’évaluation précédente. La douleur, au moment de l’évaluation, n’était pas différente chez les patients sous morphine épidurale (2.6 ± 0.4 cm, moyenne ± ET) comparativement à la morphine IV sous le contrôle du patient (3.4 ± 0.3 cm). Cependant, les patients qui recevaient de la morphine épidurale étaient mains souffrants dans la période précédant l’évaluation (4.2 ± 0.5 cm) que ceux qui recevaient de l’analgésie contrôlée par le patient (5.5 ± 0.4 cm, P <0.05). Quatre des 15 patients recevant de la morphine epidurale ont été traités pour un prurit, comparativement à aucun des 15 patients recevant de la morphine iv sous controle du patient (P < 0.05). Le rythme respiratoire minimum était plus lent chez les patients recevant de la morphine épidurale (15.0 ± 0.3) que chez ceux recevant de l’analgésie controlée par le patient (16.5 ± 0.4, P < 0.05), mais aucun patient n’a dû être traité pour dépression respiratoire. Les auteurs concluent que la morphine épidurale pourrait procurer une analgésie plus consistante que la morphine iv sous controle du patient suite à une chirurgie pour remplacement articulaire; cependant, il y a une incidence plus élevée d’effets secondaires avec la technique épidurale.

Nerve stimulator polarity and brachial plexus block.

To determine whether needle polarity significantly affects nerve stimulation during peripheral nerve block, we performed a randomized double-blinded study of 10 patients undergoing axillary block for upper extremity surgery. Using an insulated needle, we determined the minimum current necessary to elicit muscle contraction with positive and negative needle polarity at two needle placements: (A) where stimulation was first observed and (B) where stimulation was maximal. At Position A, stimulation required significantly more current when the needle was positive (2.32 +/- 0.45 mA, mean +/- SEM) than when it was negative (1.05 +/- 0.23 mA, P < 0.001). Similarly, at Position B, stimulation required more current when the needle was positive (1.49 +/- 0.49 mA) than when it was negative (0.47 +/- 0.15 mA, P < 0.001). The mean ratio of positive to negative threshold stimulation current at Position B (3.11 +/- 0.20) was significantly greater than that at Position A (2.37 +/- 0.19, P < 0.05). Our results emphasize the importance of attaching the negative terminal of the nerve stimulator to the stimulating electrode. Use of the positive terminal could lead to abandoning a block if stimulation were not obtained at a low enough current; alternatively, motor contraction might not be observed before neural contact or vascular puncture.

Delayed recognition of podophyllum toxicity in a patient receiving epidural morphine.

Podophyllum is frequently used by both dermatologists and gynecologists for the treatment of condylomata acuminata. However, the potential toxicity of topically applied podophyllum is not widely appreciated. We describe below a postanesthetic death directly related to topically applied podophyllum;

Comparison of Epidural and Patient-Controlled Intravenous Morphine Following Joint Replacement Surgery

The authors conducted a randomized, prospective study comparing epidural morphine with patient-controlled intravenous (iv) morphine in 30 patients recovering from total hip or total knee arthroplasty. Six, 18, and 24 hr postoperatively, patients used a 10 cm visual-analogue scale to indicate both their current degree of discomfort and the maximum discomfort they had experienced since the previous evaluation. Pain at the time of evaluation did not differ between patients receiving epidural (2.6 +/- 0.4 cm, mean +/- SEM) and patient-controlled iv morphine (3.4 +/- 0.3 cm). However, patients who received epidural morphine recalled less pain during the period preceding evaluation (4.2 +/- 0.5 cm) than did those receiving patient-controlled analgesia (5.5 +/- 0.4 cm, P less than 0.05). Patients receiving epidural morphine were more likely to require treatment for pruritus (4 of 15) than patients who received patient-controlled iv morphine (none of 15, P less than 0.05). Minimum respiratory rates were lower in patients receiving epidural morphine (15.0 +/- 0.3) than in those receiving patient-controlled analgesia (16.5 +/- 0.4, P less than 0.05), but no patients required treatment for respiratory depression. The authors conclude that epidural morphine may provide more consistent analgesia following joint replacement surgery than patient-controlled morphine; however, there is a higher incidence of side-effects with the epidural technique.