1996 OPEN FORUM Abstracts
All Patients Requiring High Levels of Ventilatory Support Should Be Heavily Sedated or Neuromuscularly Blocked
John M. Graybeal, CRTT Wednesday, November 6, 1996
Acutely ill patients receiving ventilatory support can be divided into two general classes of patients. Those requiring ventilatory support for relatively short duration, while a non-respiratory illness is corrected differ from those patients requiring ventilatory support for primary acute pulmonary disease (ARDS). These latter patients often require aggressive high levels of ventilatory support including, Pressure Control Ventilation, Inverse Ratio Ventilation, often requiring abnormally high respiratory rates, prolonged inspiratory times and elevated airway distending pressures. All of these therapies have the potential to increase the risk of over distending the airways and causing trauma to the lung parenchyma (barotrauma or volutrauma). Also it is these most critically ill patients in whom we now reluctantly "accept" abnormally low arterial oxygen contents and abnormally high arterial carbon dioxide concentrations, i.e. permissive hypercapnea, in order to minimize the risk of iatrogenic lung injury.
"Heavy" sedation and neuromuscular blockade should be considered whenever patients require such aggressive levels of ventilatory support. The use of neuromuscular blocking drugs may be beneficial to these patients for any one of the following reasons: Elimination of discoordinate mechanical ventilation, allowance of inverse I:E ratios, improvement in pulmonary compliance and reduction of oxygen consumption and carbon dioxide production. By increasing the patient's compliance with the ventilatory support methods being used and by decreasing the metabolic demands of the body during this critical time, the patient's risk of iatrogenic lung damage should be reduced.