Intensive care medicine
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Successful organ transplantation offers patients with end stage organ failure the chance of a normal life. The recognition of brain death allowed the use of beating heart donors and this has enabled multiple organ procurement from a single donor. Suitable patients with severe brain injury resulting in brain death, who may be potential organ donors, are to be found on both neurosurgical and general intensive care units. ⋯ The management of brain injury before death often results in abnormalities of fluid balance, due to fluid restriction and diuretic therapy. Other problems such as acute endocrine failure and the impact of their correction on ultimate organ function remains to be elucidated. Good donor maintenance in the intensive care unit and operating theatre is essential if optimal function of the transplanted organ is to occur.
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Intensive care medicine · Jan 1989
Maximum expiratory airflow during chest physiotherapy on ventilated patients before and after the application of an abdominal binder.
Chest physiotherapy using a manual ventilation technique was carried out on 9 intubated patients. One patient was studied on two occasions. ⋯ Chest physiotherapy increased the mean MEFR and application of an abdominal binder (together with physiotherapy) caused a further increase in MEFR. The mean MEFR (assuming a common Vt of 1360 ml) in each group was; (A) = 73.3 l min-1, (B) = 103.9 l min-1, (C) = 113.93 l min-1.
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Intensive care medicine · Jan 1989
Comparative StudyTransthoracic electrical bioimpedance versus thermodilution technique for cardiac output measurement during mechanical ventilation.
To study the possible influence of mechanical ventilation on the accuracy of thoracic electrical bioimpedance (TEI) in the measurement of cardiac output, we determined cardiac output concurrently by TEI using Kubicek's equation and by thermodilution in 8 acutely ill patients who were mechanically ventilated (assist/control mode) but who had no underlying respiratory failure. Cardiac outputs were lower with TEI than with thermodilution (3.97 +/- 0.80 vs 4.83 +/- 1.16 l/min p = 0.004) and there was poor correlation between the values (r = 0.41). Although there is a need to develop non-invasive techniques to measure cardiac output, the present study indicates that TEI is not reliable in mechanically ventilated patients.
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Hemodynamic monitoring is indicated in children with impending or manifest cardiocirculatory failure. Since cardiocirculatory failure is characterized by an imbalance between oxygen delivery and oxygen demand due to perfusion failure, the parameters monitored should aid in the assessment of these oxygen variables. Oxygen delivery depends on oxygen content and cardiac output. ⋯ Since the direct measurement of oxygen consumption routinely is almost impossible, global oxygen utilization represented by mixed venous oxygen saturation may be used to quantify the relationship between oxygen delivery and oxygen consumption. Justification of invasive hemodynamic monitoring depends among other things on an optimal balance between usefulness of information and complications associated with the techniques used. In future, the development of further noninvasive techniques and the scientific evaluation of recommended monitoring techniques are prospects in cardiovascular monitoring in childhood.
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Intensive care medicine · Jan 1989
Diazepam does not improve the mechanical performance of rat cardiac papillary muscle exposed to chloroquine in vitro.
Diazepam has been reported to decrease the cardiac toxicity of chloroquine but the precise mechanism involved remains unknown. Left ventricular papillary muscles from adult Wistar rats were exposed to 10(-4) M chloroquine and assigned to three groups: group I (n = 10) exposed to chloroquine alone; group II (n = 8) exposed to chloroquine and 10(-5) M diazepam; group III (n = 8) exposed to chloroquine and 10(-4) M diazepam. The main mechanical parameters measured were: maximum unloaded shortening velocity (Vmax), maximum lengthening velocity (maxVr), active force normalized per cross-sectional area (AF/s), contraction-relaxation coupling under low load (R1), load sensitivity of relaxation (Isot. ⋯ A/Isom. A (113 +/- 9, 108 +/- 3, 109 +/- 7), or Emax (75 +/- 10, 81 +/- 12, 72 +/- 16). Chloroquine was shown to be a negative inotropic agent since it decreased Vmax, AF/s and Emax, but diazepam did not restore the intrinsic mechanical performance of rat cardiac papillary muscle exposed to chloroquine, therefore 1) the protective cardiovascular effects of diazepam in chloroquine poisoning are not related to an improvement in intrinsic cardiac mechanical properties; 2) inotropic agents are therefore necessary in combination with diazepam for the treatment of severe chloroquine poisoning.