Intensive care medicine
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Intensive care medicine · Jan 1990
Measurement of extravascular lung water by thermal-dye dilution technique: mechanisms of cardiac output dependence.
The extent to which extravascular lung water (EVLW) is dependent on cardiac output was analysed in anaesthetized and mechanically ventilated pigs. EVLW was measured by thermal-dye dilution technique, by a fibreoptic thermistor catheter system (system 1), and by a thermistor catheter-external optical cuvette system (system 2). During baseline conditions, at which cardiac output was 3.65 l/min, and EVLW was 11.7 and 7.7 ml/kg b.w. with systems 1 and 2 respectively. ⋯ With system 1 the CO dependence was due to different time constants in thermistor and optical systems, and with appropriate phasing the dependence could be eliminated. With system 2 a large overestimation of the mean transit time difference between the two indicators was seen when cardiac output was low, resulting in overestimation of EVLW. It is concluded that the dependence of EVLW volume on cardiac output is an artefact due to technical problems in the design of the recording equipment rather than a reflection of pulmonary or vascular effects.
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Intensive care medicine · Jan 1990
P 0.1/PIMax: an index for assessing respiratory capacity in acute respiratory failure.
We studied airway occlusion pressure (P 0.1) and maximal inspiratory pressure (PIMax) in 10 healthy volunteers (Group A), 10 early postsurgical cardiac patients on spontaneous breathing (Group B), 10 patients mechanically ventilated for ARF (Group C), 10 patients weaning from mechanical ventilation after ARF (Group D) and 10 patients extubated after post-ARF (Group E). We calculated the index P 0.1/PIMax in an attempt to link the ventilatory demands and muscle ventilatory reserve. ⋯ When the index P 0.1/PIMax was used they were C = (90%, 100%), D = (80%, 87%) and A + B + E = (86%, 90%). We conclude that the index P 0.1/PIMax increases the reliability of P 0.1 alone to correctly classify the patients that will need either full, partial or no ventilatory support in ARF.
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Intensive care medicine · Jan 1990
Case ReportsAccidental hypothermia with cardiac arrest: complete recovery after prolonged resuscitation and rewarming by extracorporeal circulation.
A 51-year-old male remained immersed in sea water (6 degrees C) for 40 min. Brought ashore, the ECG showed asystole. Advanced life support was immediately commenced. ⋯ After 60 min of re-perfusion the patient was be weaned from bypass supported by a high-dose vasopressor infusion and nitroglycerine. He was discharged after 13 days with no evidence of any permanent organ damage. Given the advantage of providing circulatory support, extracorporeal circulation may be useful when rewarming hypothermic victims with cardiac arrest.
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Intensive care medicine · Jan 1990
Low mortality associated with low volume pressure limited ventilation with permissive hypercapnia in severe adult respiratory distress syndrome.
Many animal studies have shown that high peak inspiratory pressures (PIP) during mechanical ventilation can induce acute lung injury with hyaline membranes. Since 1984 we have limited PIP in patients with ARDS by reducing tidal volume, allowing spontaneous breathing with SIMV and disregarding hypercapnia. Since 1987 50 patients with severe ARDS with a "lung injury score" greater than or equal to 2.5 and a mean PaO2/FiO2 ratio of 94 were managed in this manner. ⋯ Only 2 died, neither from respiratory failure. There was no significant difference in lung injury score, ventilator score, PaO2/FiO2 or maximum PaCO2 between survivors and non-survivors. We suggest that this ventilatory management may substantially reduce mortality in ARDS, particularly from respiratory failure.
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Intensive care medicine · Jan 1990
ReviewPractical points in the application of oxygen transport principles.
Application of the principles of oxygen transport in the management of critically ill patients can influence the frequency of organ failure and outcome. Adequate tissue oxygen consumption in these patients may depend on a supranormal level of oxygen delivery. ⋯ The methods used to perform the measurements are reviewed. Widespread acceptance and use of oxygen transport protocols in treatment is only possible if the measurements on which they are based are accurate and properly interpreted.