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.