Critical care medicine
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Critical care medicine · Nov 1983
Left ventricular regional myocardial blood flows during controlled positive pressure ventilation and positive end-expiratory pressure in dogs.
A decrease in myocardial blood flow (MBF) has been suggested as a possible cause for the depression of left ventricular function during mechanical ventilation. In 8 dogs, hemodynamic effects of controlled mechanical ventilation with 15 cm H2O of PEEP or (CPPV15) were compared to controlled mechanical ventilation without PEEP (IPPV). Addition of PEEP caused a significant decrease in left ventricular epicardial, midwall (p less than .01) endocardial and septal (p less than .05) blood flows. ⋯ Left ventricular myocardial oxygen consumption (LVMVO2) and coronary sinus oxygen content (Ccso2) also did not show any significant change. Pulmonary vascular resistance (PVR) increased significantly (p less than .01). The observed decrease in MBF during PEEP therapy may be due to shift of the interventricular septum, reflexly mediated coronary vasoconstriction, or decreased net coronary filling pressure.
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Critical care medicine · Nov 1983
Clinical TrialPatient-controlled inhalational analgesia in prehospital care: a study of side-effects and feasibility.
A clinical trial of a 50:50 mixture of nitrous oxide and oxygen for pain relief was carried out to determine the feasibility of its use in a field setting and the side-effects produced by this sedative/analgesic. The gas mixture was delivered from a single-tank system using a demand-valve apparatus which was triggered by the patient's inspiratory effort. This "patient-controlled" sedation/analgesia was provided to 1243 patients over a period of 18 months. ⋯ No consistent or clinically adverse changes were found in BP or pulse rates. The trial supports the concept that this agent is a promising sedative/analgesic for the relief of mild to moderate pain and anxiety. Because of its safety, it is particularly suited to use in prehospital emergency care.
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Critical care medicine · Nov 1983
Effect of positive end-expiratory pressure on breathing patterns of normal subjects and intubated patients with respiratory failure.
The aims of this study included assessment of accuracy of respiratory inductive plethysmography when pulmonary hyperinflation was induced by application of PEEP, and examination of breathing patterns of normal subjects, intubated patients requiring mechanical ventilation and intubated patients immediately before extubation during application of PEEP by demand valve and high gas flow reservoir bag systems. Validation of tidal volume (VT) and end-expiratory level measured with respiratory inductive plethysmography to simultaneous spirometry (SP) was achieved with PEEP levels up to 12.5 cm H2O in 7 normals. In 17 intubated patients, almost all VT values measured with respiratory inductive plethysmography fell within +/- 10% of SP even with 2 to 3 changes of body posture. ⋯ PEEP from the high gas flow reservoir bag system produced nonprogressive rises of VT and rib cage (RC) contribution to VT, and rises of Vmin and mean inspiratory and expiratory flows between 10.0 and 12.5 cm H2O of PEEP. Intubated patients requiring intermittent mandatory ventilation (IMV) had a rapid, shallow breathing pattern unaltered by PEEP levels delivered by either system up to 12.5 cm H2O despite increases of end-expiratory level. Intubated patients who were about to be extubated breathed with patterns closer to ambulatory normal subjects with the exception of their elevated RC contribution to VT.(ABSTRACT TRUNCATED AT 250 WORDS)
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Critical care medicine · Oct 1983
Noncardiac pulmonary edema precipitated by tracheal intubation in patients with inhalation injury.
Ten patients with body surface burn and clinical evidence of inhalation injury developed transient, reversible pulmonary edema within 5 min after endotracheal intubation. Hemodynamic studies within 1 hr after intubation revealed normal cardiac output and pulmonary artery wedge pressure (WP). ⋯ It is postulated that glottic generated expiratory retard may increase alveolar pressure, thus preventing pulmonary edema. Bypass of glottis by tracheal intubation may render alveolar pressure atmospheric and facilitate edema formation.
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Critical care medicine · Oct 1983
Randomized Controlled Trial Comparative Study Clinical TrialThe risk of infection related to radial vs femoral sites for arterial catheterization.
To evaluate risk factors for infections associated with indwelling arterial catheters, 186 catheters were randomly allocated for either femoral or radial insertion in 155 critically ill patients. Femoral catheters were easier to insert and it was easier to obtain blood specimens from them. Rates of local infection at the insertion sites and rates of positive catheter-tip cultures were similar for femoral and radial catheters. ⋯ Percutaneously inserted femoral and radial artery catheters had a similarly low incidence of catheter-associated infections. There was only one catheter-related infection, and no cultured catheter was judged the cause of bacteremia. Routine prophylactic replacement of arterial catheter systems may be unnecessary in critical care units where rates of arterial catheter-associated infections are low.