Critical care medicine
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Critical care medicine · Feb 1981
Comparative StudyComparison of electronic and manometric central venous pressures. Influence of access route.
Manometric central venous pressure (CVP) measurements are still routinely used as indicators of intravascular volume, particularly during surgery and when cardiorespiratory function is assumed to be normal. The difference between manometric measurements of CVP, from a 16-gauge polyvinylchloride catheter, and those obtained electronically from the level of the right atrium through the proximal port of a pulmonary artery catheter was studied in 40 patients admitted to the ICU. ⋯ When catheters were inserted from the left subclavian vein or the internal jugular, on the other hand, manometric CVP was consistently 4-6 cm H2O higher than the electronic pressure determination. If a manometric CVP catheter is to be used, the internal jugular or left subclavian routes appear preferable.
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Critical care medicine · Feb 1981
Temporal responses of functional residual capacity and oxygen tension to changes in positive end-expiratory pressure.
PEEP is widely accepted as a therapy for some forms of acute respiratory failure (ARF). PEEP increases functional residual capacity (FRC), decreases intrapulmonary shunt fraction, and improves arterial oxygenation. The time required for FRC and arterial oxygen tension (PaO2) to stabilize after an adjustment in the level of PEEP is not clearly established. ⋯ After PEEP was applied, an average of 15 sec was required to increase FRC; the less compliant the lung, the more rapid the change. After PEEP was removed, FRC stabilized within an average of 22 sec. When PEEP, 25 cm H2O, was removed, arterial oxygenation decreased suddenly and substantially which suggests that PEEP, especially at higher levels, should not be discontinued, even momentarily, for nonessential maneuvers.
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This study evaluates the effectiveness of combining mechanical ventilation and 5 cm H2O positive end-expiratory pressure (PEEP) at the onset of adult respiratory distress syndrome (ARDS) in dogs. Five cm H2O PEEP applied at the onset of ARDS in oleic acid injured dogs resulted in a decrease in cardiac output (CO). ⋯ Control group dogs (receiving mechanical ventilation only) showed a less dramatic changing in CO, but demonstrated a dramatic drop in saturation, compromising oxygen transport of the tissues. Thus, despite decrease in CO experienced by the PEEP group, oxygen extraction at the tissue level remained high.
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Critical care medicine · Jan 1981
Ventilatory management of life-threatening bronchopleural fistulae. A summary.
The loss of a substantial portion of a critically ill patient's inspired tidal volume through a bronchopleural fistula (BPF) may significantly alter the intrapulmonary distribution of ventilation, ventilation-perfusion matching and arterial blood gases. If surgical closure of the fistulous tract is not possible, modifications of traditional ventilatory methods may be necessary to preserve adequate gas exchange. ⋯ Although these techniques might be considered investigational, they can be justified: (1) in the presence of profound hypoxemia and hypercarbia caused by a large BPF, and (2) when reduced gas loss through the fistula is considered an important part of therapy. All the methods discussed below apply in patients requiring endotracheal intubation and mechanical ventilation, whereas some (as indicated in the text) can be used during spontaneous breathing.
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The administration of albumin in the initial resuscitation of shock remains highly controversial. Impaired coagulation in the critically injured patient has recently been added as an argument against the use of supplemental albumin. This study investigated the hemostatic effects of albumin therapy after hemorrhagic shock. ⋯ Coagulation parameters were measured before bleeding, immediately after resuscitation, and on days 2, 3, and 4. The changes in platelet count, platelet function, and serum fibrinogen were similar in the albumin treated and control animals. Although the prothrombin time and partial thromboplastin time were more prolonged in the albumin group, the changes were not sufficient to produce clinical bleeding.