Critical care medicine
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Critical care medicine · Dec 1987
Comparative StudyMetabolic acidosis not due to lactic acidosis in patients with severe acute asthma.
Asthmatics seeking emergency care for severe acute asthma may show metabolic acidosis. We sought to determine the frequency of metabolic acidosis in such patients and to assess the relative contributions of renal bicarbonate loss and lactic acid accumulation to this acidosis. Twenty-two asthmatics (21-71 yr; four males, and 18 females) who came consecutively to the emergency department with severe acute asthma were studied. ⋯ In the one patient with an elevated whole blood lactate level, the concentration of lactate in excess of normal (0.45 mmol/L) could not account for the magnitude of the base deficit (-4.9 mEq/L). We conclude that a) nonanion gap metabolic acidosis is very common in asthmatics with acute severe asthma (prevalence 45% in our series), and b) the mechanism of the base deficit in these patients is excessive renal bicarbonate excretion. We believe that the latter occurs as a renal compensatory response to a preceding period of hypocapnia due to hyperventilation related to worsening asthma.
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Critical care medicine · Dec 1987
Comparative StudyRelationship of pulse oximetry to arterial oxygen tension in infants.
Pulse oximetry is a useful technique for noninvasive oxygen monitoring in sick infants. We simultaneously measured oxygen saturation by pulse oximetry and on arterial blood samples by co-oximetry as well as PaO2 and the relative content of fetal (F) and adult hemoglobin in order to evaluate the reliability of pulse oximetry. Comparisons were made in triplicate in ten infants with acute cardiorespiratory disease less than 7 days of age and in 11 infants with chronic lung disease greater than 28 days of age. ⋯ Nonetheless, correction of oxygen dissociation curves for type of hemoglobin in these acute infants failed to improve the correlation between calculated and measured PaO2. We conclude that pulse oximetry saturations and their derived PaO2 values correlated well with measured arterial saturation and PaO2 obtained from arterial blood samples in neonates with chronic lung disease and prolonged oxygen dependence. In infants with acute cardiorespiratory problems, pulse oximetry unreliably reflects PaO2, but may be useful in detecting clinical deterioration.
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Critical care medicine · Dec 1987
Comparative StudyRadial arterial catheters in children and neonates: a prospective study.
Over a 3-yr period (1982 to 1984), 533 arterial catheters were inserted in 476 patients admitted to the pediatric ICU or the operating room. Radial arterial catheterization with small-bore, 0.8-mm, 22-ga Teflon cannulas was the most common method (376 of 533 cannulations), and 296 of these catheters were inserted in patients less than 1 yr of age. All catheters were flushed intermittently with heparin (12.5 U/ml) in isotonic saline. ⋯ No complications were noted, and the proportion of catheter malfunction decreased. This study confirms the safety of radial arterial catheterization in children and neonates. The continuous flushing system considerably improved catheter patency compared to a method using intermittent flushing.
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Critical care medicine · Dec 1987
Comparative StudyResuscitation with 7.5% NaCl in 6% dextran-70 during hemorrhagic shock in swine: effects on organ blood flow.
We previously reported that small volume infusions of 7.5% NaCl in 6% dextran-70 (HSD) are superior to equal volumes of normal saline (NS) or 7.5% NaCl in the ability to resuscitate animals from an otherwise lethal hemorrhage. In the present experiment, we evaluated organ blood flow in unanesthetized swine bled 46 ml/kg in 15 min and subsequently infused with a volume of HSD (n = 5) or NS (n = 5) equal to 25% of the shed blood. Radiomicrospheres were injected before hemorrhage, immediately after hemorrhage, and 5 and 30 min after treatment. ⋯ NS was unable to increase these flows significantly above post-hemorrhage levels. We conclude that small volumes of HSD can significantly improve organ blood flow after hemorrhagic shock. This improvement in flow may explain the increased survival observed with this solution and may attenuate some of the later complications of hemorrhagic shock.
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Critical care medicine · Nov 1987
Comparative StudyNoninvasive pulse oximetry in children with cyanotic congenital heart disease.
Arterial oxygen saturation, determined noninvasively by pulse oximetry in 32 pediatric patients with cyanotic congenital heart disease (CHD), was compared with oxygen saturation measured by a cooximeter in simultaneously obtained arterial blood samples. The patients were studied in the cardiac catheterization laboratory, operating room, and ICU. Excellent correlation by linear regression (n = 108, r = .95) was observed between the two methods at oxygen saturations ranging from 35% to 95%. These observations show that in infants and children with cyanotic CHD, arterial oxygen saturations can be determined accurately and reliably by pulse oximetry at rest and during changing circulatory states.