Resuscitation
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HFPPV is not a jet technique, as it works without air entrainment. A low-compression ventilator, with a conventional rate of 20/min, provides efficient intrapulmonary gas mixing; however, with higher rates of 60-100/min the high inspiratory flow improves transfer/mixing of gas in the conducting airways. ⋯ It is important to note that enhanced gas mixing and improved gas distribution during HFPPV in acute respiratory failure patients are accomplished with lower mean airway pressure, thereby reducing barotrauma. In the future, versatile low-compression ventilators for volume-controlled IPPV and HFPPV will hopefully improve safety, efficiency and patient acceptance of mechanical ventilation in acute respiratory failure.
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Plasma growth hormone, cortisol, insulin and blood glucose concentrations were measured intra- and postoperatively in ten patients who underwent open heart surgery with moderate hypothermia. Diazepam-ketamine anaesthesia for 10-20 min failed to precipitate any significant alterations in the levels of measured hormones and blood glucose. In the pre-bypass period of surgery, an increase in cortisol and a slight elevation in growth hormone levels was observed; insulin level showed no change in spite of marked hyperglycaemia. ⋯ The post-bypass period with rewarming the restoring spontaneous circulation was characterized by further marked increase in cortisol and growth hormone levels and, in spite of decreasing levels of blood glucose, by a paradoxical elevation in plasma insulin. It is suggested that hypothermia, haemodilution, reduced tissue perfusion affecting endocrine glands, as well as denaturation of some hormones in the oxygenator, participate in the moderate endocrine response, disproportionate to the stress of cardiopulmonary bypass surgery. The rise in hormone levels on terminating bypass seems to be dependent on the improved blood flow to endocrine glands due to recovered spontaneous circulation, rewarming and, as for insulin, presumably even on the reduced inhibitory effect of catecholamines.
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The interrelations among core temperatures (cardiac, esophageal, tympanic, rectal), skin temperature, and cardiovascular function (cardiac output, arterial pressure, heart rate, total peripheral resistance) were studied in a conscious subject during entry into mild hypothermia through cold water (10 degrees C) immersion, and during rewarming by three basic procedures: peripheral heat donation (bath); core heat donation (inhalation); and no exogenous heat (spontaneous). Swan-Ganz catheterization of the heart enabled measurement of cardiac temperature as well as cardiac output by the thermal dilution method. During cooling, all sites of core temperature measurement showed similar rates of entry into hypothermia. ⋯ This afterdrop coincided with cardiovascular changes including abrupt decreases in arterial pressure and total peripheral resistance, along with increases in heart rate and cardiac output. Such evidence of increased peripheral circulation was not observed with the inhalation and spontaneous methods. The findings relate to experimental evaluation of rewarming techniques and principles for resuscitation of hypothermia victims, especially in the first-aid situation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Advantages of dextran 70 over Ringer acetate solution in shock treatment and in prevention of adult respiratory distress syndrome. A randomized study in man after traumatic-haemorrhagic shock.
Twenty-three patients aged 20-58 years in a serious state of shock and suffering from major pelvic and femoral fractures sustained in traffic accidents were studied. As initial fluid management, either dextran 70 (1000-1500 ml) together with Ringer's acetate solution (2000-3000 ml), or Ringer's acetate alone (5000-8000 ml), was administered on a random basis. Thus, 12 patients received dextran and 11 patients crystalloid treatment to counteract shock. ⋯ To maintain a stable circulation and a urinary output above 50 ml/h the Ringer patients required significantly more (P less than 0.001) crystalloid solution (910 +/- 300 ml) daily than the dextran patients (460 +/- 400 ml). The frequency of adult respiratory distress syndrome (ARDS) was significantly lower (P less than 0.05) in the dextran group (0 of 12) than in the Ringer group (4 of 11). Thus, in the initial treatment of traumatic-haemorrhagic shock and in the post-resuscitative period dextran 70 would seem of advantage over Ringer's acetate both in shortening the shock period and in reducing the frequency of adult respiratory distress syndrome.
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The authors have analysed the incidence of specific complications in a series of 420 intracaval catheters placed in 388 patients, using six transcutaneous puncture techniques: supraclavicular and infraclavicular subclavian, external and internal jugular, antecubital and brachiocephalic approaches. Strict and moderate criteria were used to evaluate the frequency of complications. Using strict criteria, the lowest rate of surgical complications (5%) was found with the antecubital and external jugular approach, followed by infraclavicular (6.7%) and supraclavicular (9.3%) subclavian techniques; the highest rate was seen with internal jugular (10%) and brachiocephalic (15%) routes. ⋯ Manifest thromboembolic complications were observed only in the brachiocephalic and antecubital groups (2.5% and 10%, respectively), the overall incidence of pulmonary embolism being 0.2%. None of the approaches used can be recommended as an exclusive method of choice. The risks of central venous catheterization should be minimalized by adherence to strict principles of placing as well as care of the indwelling intravenous catheters.