Critical care medicine
-
Critical care medicine · Mar 1983
Pressure-time relationships of pressure-limited neonatal ventilators.
A pressure-limited ventilator (Bourns BP-200, Anaheim, CA) and a simple, manually operated constant flow ventilator were studied using a commercially available infant lung simulator (Bourns LS-130, Anaheim, CA). The characteristics of inspiratory pressure-time relationships during ventilation with these ventilators were analyzed. ⋯ Qualitatively similar tracings were obtained with the BP-200 during normal ventilation, with simulated airway obstruction and thoracic restriction. These findings suggest that monitoring pressure-time relationships may be useful in the qualitative assessment of resistance and compliance during pressure-limited ventilation of neonates.
-
Determining adequacy of mechanical ventilation is as important during CPR as in a more stable situation (such as, a patient on a ventilator in an ICU). Yet, such assessment during CPR usually only means listening for breath sounds, checking chest excursion, and blood gases. Exhaled tidal volume (VT) was measured on 45 intubated adult patients during resuscitation using a Wright's spirometer attached to a T-valve above the endotracheal tube. ⋯ Our findings suggest that lung compliance is markedly reduced within a short time after cardiac arrest. Fifty-five % of patients in this series could not be adequately oxygenated (PaO2 less than 50 torr) despite an FIO2 of 0.8 and adequate ventilation. Due to the reduced cardiac output during CPR causing venoarterial shunting, it is speculated that pulmonary edema is the most plausible explanation for this observation.
-
Critical care medicine · Feb 1983
Comparative StudyEffect of the dynamic response of transducer-tubing system on accuracy of direct blood pressure measurement in patients.
The dynamic responses of 3 transducer-tubing systems (TTS) were documented using square and sine wave generators. The TTS tested were P23 ID with 5 feet tubing (P23-5'), P23 ID with 6 inches tubing (P23-6") and P50A transducer with no tubing (P50). Natural frequencies were 45, 33, and 7 Hz for P50, P23-6", and P23-5', respectively. ⋯ However, the differences were greater with radial, compared to brachial arterial cannulation (p less than 0.02). There were no differences in systolic pressures measured with P23-6" and P50. There were no differences in diastolic or electronic mean pressures recorded by the 3 TTS.