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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Some bacteria have a natural tendency to adhere to available surfaces and to form biofilms. Biofilms have been demonstrated on right heart flow-directed catheters, endocardial pacemaker leads, urinary catheters, and other medical devices. In this study, we examined arterial and central venous catheters that had been in place in ICU patients between 1 and 14 days for the presence of bacterial biofilms by scanning electron microscopy, transmission electron microscopy, and a special scraping/sonication bacterial recovery technique. The data taken from these processes were compared with skin entry site swabs and blood cultures and correlated with patient data on infection, bacterial colonization, and antibiotic use. ⋯ Direct microscopic examination of 68 vascular catheters that had been in place 1 to 14 days showed that most (81%) were colonized by bacteria growing in slime-enclosed biofilms. In many cases, this colonization of catheter surfaces could be confirmed by special biofilm culture recovery methods. Although the clinical importance of bacterial biofilms on catheter surfaces is speculative, their presence and potential to serve as a nidus for infection and bacteremia in critically ill immunocompromised hosts are cause for concern.
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Critical care medicine · May 1992
Plasma catecholamine concentrations after successful resuscitation in patients.
To measure plasma catecholamine concentrations after cardiopulmonary resuscitation (CPR) and to correlate catecholamine concentrations with heart rate (HR), BP, and plasma glucose and lactate concentrations. ⋯ After CPR, plasma catecholamine concentrations remained at high values but they did not lead to increases in BP, HR, or circulating glucose concentrations.
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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.
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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.