Intravenous magnesium re-establishes neuromuscular block after spontaneous recovery from an intubating dose of rocuronium: a randomised controlled trial.

CONTEXT: Intravenous magnesium deepens non-depolarising neuromuscular block. OBJECTIVE: To assess whether intravenous magnesium has the potential to re-establish paralysis in patients who have just recovered from a non-depolarising neuromuscular block. DESIGN: Prospective randomised double-blind controlled study. PATIENTS: Twenty non-obese patients ranging in age from 18 to 80 years were enrolled. Exclusion criteria were a history of liver, kidney or neuromuscular disease and intake of medications interacting with neuromuscular blocking agents. INTERVENTION: After spontaneous recovery from an intubating dose of rocuronium had been achieved (train-of-four ratio ≥0.9), patients were given either a bolus dose of magnesium 50 mg kg(-1) intravenously or an equivalent volume of isotonic saline over 5 min. MAIN OUTCOME MEASURES: The train-of-four ratio was measured every minute until the end of surgery. The primary endpoint was the proportion of patients who experienced a decrease in train-of-four ratio following administration of magnesium or saline. RESULTS: Following infusion of the study solution, the train-of-four ratio decreased in all patients in the magnesium group in contrast to none in the saline group (P<0.001). On average, magnesium-induced train-of-four ratio depression reached a nadir of 0.49 after 10 min and lasted for 45 min. CONCLUSION: A bolus dose of intravenous magnesium 50 mg kg(-1) re-establishes a clinically relevant degree of muscle paralysis in patients who have just recovered from a non-depolarising neuromuscular block. TRIAL REGISTRATION: EudraCT.ema.europa.eu 2009-017372-24.

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors.

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.