Critical care medicine
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Critical care medicine · Jul 1982
Predictive value of stridor in detecting laryngeal injury in extubated neonates.
We evaluated 73 consecutively extubated neonates for evidence of acute laryngeal injury from intubation. Hoarseness and stridor were graded by a clinical scoring system. ⋯ All patients with stridor had moderate or major injury, as did 38% of patients without stridor. Stridor was quite specific for detecting moderate or major injury but did not identify the type of injury.
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Critical care medicine · Jul 1982
Hemodynamic response to changes in ventilatory patterns in patients with normal and poor left ventricular reserve.
Hemodynamic effects of controlled mechanical ventilation (CMV), intermittent mandatory ventilation (IMV), and intermittent mandatory ventilation with 5 cm H20 PEEP (IMV 5 peep) were studied in 20 patients after aortocoronary bypass surgery. Significant increases in cardiac index (CI) and stroke volume index (SI) (p less than 0.01) resulted in patients with normal left ventricular end-diastolic pressure (LVEDP) and ejection fraction (EF) changing from CMV to IMV. With a change from IMV to IMV 5 peep, the CI and SI returned to CMV values. ⋯ We conclude that changing from CMV to IMV has salutory effects on the patient's hemodynamic values with normal left ventricular function. But in patients with failing left ventricle, volume overload of right ventricle which occurs with the institution of spontaneous respiration during IMV has deleterious effects on the hemodynamic variables. These deleterious effects can be effectively negated by the application of IMV 5 peep.
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Several recent articles have suggested the use of mean airway pressure (Paw) as an index of the physiological effect of ventilating pressures. To facilitate the understanding of this parameter, operational formulas are derived by applying the explicit, mathematical definition of Paw to several clinically relevant pressure waveforms. These formulas are then generalized to apply to any wave shape. It is shown that any pressure waveform can be characterized by a waveform constant K, knowledge of which permits the estimation of Paw using information from either airway pressure recordings or the control settings and pressure gauges on conventional ventilators.
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Critical care medicine · Jun 1982
Elective cricothyroidotomy: a clinical and histopathological study.
Elective cricothyroidotomy was carried out on 61 adult patients in the ICU between June 1977 and October 1980. This procedure replaced elective tracheotomy in those patients who were judged to require respirator treatment for a period longer than 72 h. Twenty-six of the patients were examined by the ENT department. ⋯ Contraindications to cricothyroidotomy are endotracheal intubation for a period longer than 72 h, respiratory difficulties after previous endotracheal intubation, and acute infections of the larynx. Cricothyroidotomy is faster and much easier than tracheotomy. The authors believe that every doctor who works in intensive care should be able to carry out this procedure.
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Critical care medicine · Apr 1982
Comparative StudyHemoglobin solution in the treatment of hemorrhagic shock.
The major physiological effects of hemorrhage are hypovolemia and anemia. The administration of an oxygen-carrying plasma expander, such as crystalline hemoglobin solution (CHb), can restore both of these deficits while avoiding many of the logistical problems entailed in the use of blood. The authors have used Chb to treat severe hypovolemia and anemia in separate canine models and found it to be highly effective. ⋯ Hemodynamic responses to low P50 CHb, however, suggest that oxygen offloading at the tissue level is compromised by the high oxygen affinity of unmodified CHb. Whereas such oxygen offloading deficits may be compensated for in the chronic situation, they may be of crucial importance in severe trauma where oxygen transport is often limited by arterial desaturation, low cardiac output, maldistribution of perfusion and interstitial water overload. The development of a lower-affinity CHb is, therefore, of the essence.