The effects of magnesium sulfate on neuromuscular blockade by cisatracurium during induction of anesthesia.

BACKGROUND: During the induction of anesthesia, patients are at risk of aspiration while awaiting full muscle relaxation. Magnesium has been shown to have synergistic effects with neuromuscular blocking drugs. We tested if magnesium, as an adjunct, increases the speed of onset of muscle relaxation, thereby decreasing the risk of aspiration. METHODS: Eighty-eight American Society of Anesthesiologists (ASA) physical status 1 or 2 patients were randomly assigned to three groups. Group Mg-0 received 100 mL of normal saline, whereas groups Mg-25 and Mg-50 received magnesium sulfate at doses of 25 and 50 mg/kg, respectively. Anesthesia was induced with thiopental 5 mg/kg and cisatracurium 0.15 mg/kg. A peripheral nerve stimulator and single-twitch test was performed on the ulnar nerve until the twitch responses to stimulation had disappeared, and the times were recorded. Then the patients were intubated and anesthesia was maintained with 100 µg/kg/min of propofol. The intensity of blockade was measured at regular time intervals with the post-tetanic count test. RESULTS: The mean times to muscle relaxation in groups Mg-0, Mg-25, and Mg-50 were 226, 209, and 188 s, respectively (P = 0.047). The intensity of the block increased with the dose of magnesium, and remained highest in group Mg-50 at all times measured (P < 0.05). The speed of onset and the intensity of muscle relaxation increased as higher doses of magnesium were used. CONCLUSION: The increased speed of onset of muscle relaxation produced by magnesium is not substantial enough to justify its use in combination with cisatracurium in rapid sequence induction.

Comparative induction of controlled circulation by magnesium and remifentanil in spine surgery.

AIM: To evaluate the efficacy of magnesium sulfate (MGS) in comparison with remifentanil for induction of relative hypotension in posterior fusion of spine (PSF). METHODS: In this randomized clinical trial, 40 patients with the American Society of Anesthesiologists I and II physical status undergoing lumbar PSF were randomized to receive remifentanil (REM) 0.15 µg/kg or MGS 50 mg/kg for controlled hypotension. The administering anesthesiologist was blinded to the medication. Continuous infusion was maintained at a fixed volume rate to deliver precalculated doses of either study drugs. All other aspects of anesthesia and surgery were similar in the two groups. The target mean arterial pressure (MAP) range used in this study was 60-70 mmHg. In the course of surgery, the hemodynamic variables, volume of blood loss, urine output, fluid intake and surgeon's satisfaction were recorded. Data was analyzed with SPSS version 13.0 and P values less than 0.05 were considered significant. RESULTS: Twenty patients in the MGS group and 19 patients in the REM group were studied. There was no difference between the two groups in the hemodynamic variables, blood loss, urine output, fluid requirement and surgeon's satisfaction for exposure. The target MAP was achieved in 75% of Mg and 58% of remifentanil groups. Although a higher number of patients in the REM group required nitroglycerin (42.1%) to reach the target MAP than those in the MGS group (25%), this difference was not statistically significant (P = 0.32). CONCLUSION: Our findings showed that in patients undergoing lumbar PSF surgery, remifentanil and MGS have a similar hypotensive effect and comparable amount of blood loss without any significant adverse effects.

Anesthesia Personnel's Knowledge of, Attitudes Toward, and Practice to Prevent Needlestick Injuries.

Anesthesia personnel are at risk for needlestick injuries (NSIs). This study evaluated the knowledge of, attitudes toward, and practice of preventing NSIs among anesthesia personnel in four Iranian university hospitals. A self-administered anonymous questionnaire was distributed to 104 anesthesia personnel. In addition, hospital infection control center records were reviewed. The prevalence of NSI among anesthesia personnel was 56.8%. Only 32.2% reported their NSI. Men were more knowledgeable about the risks associated with NSI and the application of standard precautions than women, but were also more likely to experience NSI. Standard precautions were often not followed. In contrast with other hospital staff, most reported NSIs among anesthesia personnel produced high-risk exposures. The knowledge and prevention practices of anesthesia personnel related to needles and other sharps were not satisfactory. These health care providers need appropriate training on standard precautions and administrative oversight to improve their practices. Anesthesia personnel's gender and position should also be considered to improve compliance.