Critical care medicine
-
Critical care medicine · Mar 1994
ReviewComponents of the work of breathing and implications for monitoring ventilator-dependent patients.
a) To discuss the components of the work of breathing using an established physiologic model (Campbell diagram); b) to describe the requirements of a monitor to measure work; and c) to discuss the implications and relevance for assessing the work of breathing of ventilator-dependent patients. ⋯ Accurate measurement of physiologic and imposed work performed by the patient are essential to assess the afterload on the respiratory muscles, diagnose specific work of breathing abnormalities, and monitor the effects of interventions to mitigate respiratory muscle loading. Work of breathing data are useful in formulating objective guidelines for setting the ventilator appropriately to optimize respiratory muscle loads, e.g., selecting an appropriate amount of pressure support ventilation to decrease the work of breathing to a specific level.
-
Critical care medicine · Mar 1994
Magnetic resonance imaging of the heart during positive end-expiratory pressure ventilation in normal subjects.
Magnetic resonance imaging was used to assess the effects of ventilation with positive end-expiratory pressure (PEEP) on cardiac volumes, especially on atrial volumes as well as to determine semiquantitative measurements of spatial interactions between heart, lungs and chest. ⋯ Left and right ventricular end-diastolic volumes and stroke volumes decreased significantly during ventilation with PEEP at 15 cm H2O, as did end-systolic atrial volumes. Volume changes in association with changes of chest and heart configuration suggest external cardiac compression by the expanding lungs. Furthermore, this study illustrates the feasibility of magnetic resonance imaging in mechanically ventilated patients.
-
Critical care medicine · Mar 1994
Continuous infusion of haloperidol controls agitation in critically ill patients.
To evaluate the safety and efficacy of continuous infusion of haloperidol in treating agitated critically ill adult patients. ⋯ Continuous infusion of haloperidol effectively controls severe agitation in critically ill patients, reduces requirements for bolus administration of sedatives and nursing time lost to that task, and may facilitate ventilator weaning. Parenteral administration of haloperidol was associated with few complications in > 1,340 patient-hours of continuous administration.
-
Critical care medicine · Mar 1994
Optimal release time during airway pressure release ventilation in neonatal sheep.
To systematically investigate the effect of altering release time during airway pressure release ventilation in a neonatal animal model before and after oleic acid-induced acute lung injury. ⋯ In this neonatal laboratory model, release times that were much shorter than previously reported maintained clinically acceptable oxygenation and ventilation. The optimal duration of the release time is a function of the time constant of the respiratory system. During airway pressure release ventilation, alveolar ventilation was maintained without apparent lung volume loss with release times of between 4 tau and 10 tau.