ABSTRACT
Neuromuscular blocking agents (NMBA) are frequently utilized in the ICU, primarily to facilitate mechanical ventilation. An ideal NMBA is nondepolarizing, has no propensity to accumulate, is easily titrated, has a rapid onset and offset, does not rely on organ function for metabolism, and has no toxic or active metabolites. Current NMBAs are classified as aminosteroids or benzylisoquinoliniums and have different features, but none are ideal. Selection of the best NMBA is determined by individual patient characteristics. Proper use of these agents includes a comprehensive plan to manage all aspects of care affected by NMBA, as well as monitoring of clinical effect and degree of neuromuscular blockade via periodic peripheral nerve stimulation. There are well-recognized complications of NMBA, including prolonged drug effect and acute quadriplegic myopathy. The latter condition can result in prolonged rehabilitation. The use of an NMBA can be essential for the successful outcome from critical illness; however, cautious use of these agents with a structured approach to minimize complications is urged.
ABSTRACT
The effects of amrinone and CaCl2 on pulmonary vasculature and biventricular function in sheep with acute lung injury (ALI) were studied. Seven sheep were ventilated with a tidal volume of 10-12 ml.kg-1 with end-tidal CO2 of 40 +/- 5 mmHg (5.3 +/- 0.7 kPa) after acute lung injury was induced with up to 30 mg kg-1 of ethchlorvynol (ECV). Biventricular function and hemodynamic profiles were estimated with a rapid computerized thermodilution method and modified pulmonary artery catheters after acute lung injury, following a loading dose (1 mg kg-1) and maintenance dose (5 micrograms kg-1 min-1) of amrinone and after a bolus dose of CaCl2 (20 mg kg-1). ECV successfully induced acute lung damage in sheep, causing significant increases in pulmonary artery pressure (PAP) and pulmonary vascular resistance index (PVRI). Amrinone reversed the unfavorable changes induced by ECV, significantly reducing PAP, PVRI and left ventricular end-diastolic volume (LVEDV). CaCl2, however, reversed the effect of amrinone and increased PAP, PVRI, and LVEDV but decreased left ventricular ejection fraction.
