Critical care : the official journal of the Critical Care Forum
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Comparative Study
Femoral vein size in newborns and infants: preliminary investigation.
The femoral vein is an important site for central venous access in newborns and infants. The objectives of this study are to determine whether age or weight can be used clinically to predict the size of the femoral vein in newborns and infants, and to compare the size of the vein in each individual in both the supine and reverse Trendelenburg positions. ⋯ Weight is predictive of femoral vein diameter in infants, but not in newborns. In infants, weight might serve as a more sensitive index for estimating size of the femoral vein in order to determine accurately the size of intravascular catheter appropriate for cannulation. The diameter of the femoral vein increases in the reverse Trendelenburg position compared with that in the supine position in both newborns and infants. A large prospective study is required to validate these findings.
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Comparative Study
A new device for 100 per cent humidification of inspired air.
STATEMENT OF A new humidifier for use during mechanical ventilation in endotracheally intubated patients is described and tested. The humidifier is based on a heat-moisture exchanger, which absorbs the expired heat and moisture and releases it into the inspired air. ⋯ In bench tests using constant and decelerating inspiratory flow and minute volumes of 3-25 l the device gave an absolute humidity of 41-44 mg/l, and it reduced the amount of water consumed in eight mechanically ventilated patients compared with a conventional active humidifier. During a 24-h test period there was no water condensation in the ventilator tubing with the new device.
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The modern intensive care unit (ICU) has evolved into an area where mortality and morbidity can be reduced by identification of unexpected hemodynamic and ventilatory decompensations before long-term problems result. Because intensive care physicians are caring for an increasingly heterogeneous population of patients, the indications for aggressive monitoring and close titration of care have expanded. Agitated patients are proving difficult to deal with in nonmonitored environments because of the unpredictable consequences of the agitated state on organ systems. The severe agitation state that is associated with ethanol withdrawal and delirium tremens (DT) is examined as a model for evaluating the efficacy of the ICU environment to ensure consistent stabilization of potentially life-threatening agitation and delirium.
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The recent Cochrane report on albumin administration is analysed and criticised on the grounds of clinical methodology, content and interpretation. Although it is naïve and illogical to treat hypoalbuminaemia with albumin infusions, a more balanced view on the use of albumin for resuscitation in acute hypovolaemia is necessary. Once the acute phase of critical illness is past, interstitial volume is often expanded causing oedema, with a low plasma volume. We argue for the use of salt-poor albumin solutions in this situation and conclude that, on current evidence, the assertion that albumin should be avoided in all situations is irrational and untenable.
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Physiological background concerning mechanics of the respiratory system, techniques of measurement and clinical implications of pressure-volume curve measurement in mechanically ventilated patients are discussed in the present review. The significance of lower and upper inflection points, the assessment of positive end-expiratory pressure (PEEP)-induced alveolar recruitment and overdistension and rationale for optimizing ventilatory settings in patients with acute lung injury are presented. Evidence suggests that the continuous flow method is a simple and reliable technique for measuring pressure-volume curves at the bedside. In patients with acute respiratory failure, determination of lower and upper inflection points and measurement of respiratory compliance should become a part of the routine assessment of lung injury severity, allowing a bedside monitoring of the evolution of the lung disease and an optimization of mechanical ventilation.