Critical care medicine
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Critical care medicine · May 1992
Validation of bedside measurements of absolute human renal blood flow by a continuous thermodilution technique.
There is a clinical need for a system that would allow rapid assessment of renal blood flow in patients with oliguric circulatory shock. A local, continuous thermodilution technique for the measurement of renal venous blood flow, using readily available equipment, was developed. To test the hypothesis that this system would allow measurement of renal blood flow in clinical situations, we compared simultaneous measurements made by the continuous thermodilution technique with measurements of: a) absolute flow measured by volumetric collection in an in vitro flow model; b) renal arterial blood flow measured by electromagnetic flow probe under changing hemodynamic conditions in nine pigs; and c) calculated renal blood flow derived from a clearance technique in 16 patients after cardiac catheterization. The technique utilizes a short-duration, constant infusion of room temperature normal saline into the renal vein via a retrograde thermodilution catheter, with measurement of flow at a thermistor 1 cm back from the tip of the catheter. ⋯ This technique is simple to use, requires only venous cannulation and injection of normal saline, and allows rapidly repeatable, immediately available measurements of renal blood flow in a wide range of clinical circumstances, including severe renal impairment or anuria.
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Critical care medicine · May 1992
ReviewSelective decontamination of the digestive tract in the intensive care unit: current status and future prospects.
To evaluate the available data on selective decontamination of the digestive tract. This therapy aims to prevent infection in critically ill patients admitted to ICUs. Microbial carriage in the oropharynx, stomach, and gut; infection; mortality rate; and antibiotic resistance are the outcome events that are being reviewed. ⋯ There is a general consensus about the efficacy of selective decontamination in diminishing microbial carriage and acquired infection rates, although conclusions about benefits related to mortality rates vary. Differences in mortality rate are found in the selective decontamination studies of patients with curable diseases, including multitrauma and cardiovascular patients. More data on resistance, collected over a longer period of time, are needed. Practical problems of blinding and the major ecological effect of selective decontamination may explain the lack of a randomized, placebo-controlled, double-blind trial.
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Critical care medicine · May 1992
Randomized Controlled Trial Clinical TrialEffects of diltiazem on oxygen delivery and consumption after asphyxial cardiac arrest and resuscitation.
Calcium-channel blockers may attenuate vasospasm after transient ischemia and improve organ blood flow after resuscitation. Our aim was to assess the effect of diltiazem on systemic oxygen delivery and consumption, hemodynamics, electroencephalogram (EEG), and organ blood flow after restoration of spontaneous circulation. After a 3-min period of asphyxial cardiac arrest, 14 pigs (20 to 27 kg) were randomly allocated to treatment with either diltiazem (0.1 mg/kg bolus followed by an iv infusion of 0.025 mg/min/kg over 120 mins) or placebo, given at 5 mins after successful resuscitation. Organ blood flow was measured using tracer microspheres 120 mins after resumption of spontaneous circulation. ⋯ Diltiazem causes an increase in systemic oxygen delivery index by promoting vasodilation, but it does not change systemic oxygen consumption index in comparison to placebo treatment. It may be that an impairment in local autoregulation and/or in oxidative metabolism at the cellular or subcellular level was the reason why diltiazem did not improve these derangements. The observed increase in cerebral blood flow and in EEG recovery may be beneficial to the brain after a period of asphyxia.
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Critical care medicine · May 1992
Randomized Controlled Trial Clinical TrialGastric colonization and pneumonia in intubated critically ill patients receiving stress ulcer prophylaxis: a randomized, controlled trial.
To study the effects of pharmacologically increasing gastric pH on gastric colonization and the development of pneumonia in intubated critically ill patients. ⋯ Pharmacologically increasing gastric pH increases the risk for developing pneumonia in intubated critically ill patients. The pneumonia occurs earlier than in untreated control patients.
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Critical care medicine · May 1992
A simple method for the measurement of intrinsic positive end-expiratory pressure during controlled and assisted modes of mechanical ventilation.
To evaluate a new and simple method for the measurement of intrinsic positive end-expiratory pressure during controlled and assisted modes of mechanical ventilation. ⋯ The manual valve method can be used to determine intrinsic positive end-expiratory pressure during controlled and assisted modes of ventilatory support with current ventilators. The availability of such an approach should facilitate the routine monitoring of intrinsic positive end-expiratory pressure in mechanically ventilated patients, thereby aiding clinical decision-making and management in these critically ill individuals.