摘要:

We examined the incidence and mortality of adult respiratory distress syndrome (ARDS) in patients receiving emergency medical care at a large metropolitan medical center. The patients were classified into eight high-risk categories and monitored prospectively until discharge or death. Over a period of 12 months, 11,112 such patients entered the emergency room. Of 4926 who were admitted to the hospital acutely ill, 90 (2%) developed ARDS. Thirty-six percent of these survived. ARDS occurred in 25% of patients admitted with acquired immune deficiency syndrome andPneumocystis cariniipneumonia, and mortality in these patients was 86%. Aspiration pneumonia was the primary cause of ARDS in 37% of the patients, who also had a similar mortality rate (85%). Mortality was also high in patients with multisystem organ failure or with ARDS and disseminated intravascular coagulation. These results indicate that there probably is a relatively low incidence of ARDS among hospital patients admitted with high-risk diagnoses.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Gas transport during high-frequency oscillation (HFO) and high-frequency jet ventilation (HFJV) was compared in a simple lung model of human conducting airways. The delivery of gas to distal airways was assessed by measuring the dilution of 5% CO2, introduced separately into the model. Increasing frequency from 1.0 to only 1.7 Hz redistributed gas into straighter airway paths during HFO. Gas flow rates during HFO were sinusoidal, and CO2dilution at the most distal airway sampling site was a function of both mean and peak flow rates. CO2dilution increased as frequency increased, even though tidal volume (Vt) was constant. Peak flow increased as either Vt or frequency was increased (range 132 to 2167 ml/sec). During HFJV, flow approximated a square-wave function. Peak flows during HFJV were lower than during HFO, except at mean flows less than 167 ml/sec. Although CO2dilution at the most distal airway sampling site increased as Vt increased during HFJV, CO2dilution actually decreased as frequency was increased at any given Vt. Thus, in this model, gas transport in large airways differed during HFO or HFJV, and was related to peak as well as mean flows. Also, the distribution of gas within the airways changed as frequency increased.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

A polarographic conjunctival oxygen sensor was used to measure oxygen tension in a tissue bed supplied by the internal carotid artery. The shared vascular source of the conjunctiva and brain suggests that conjunctival Po2monitoring may provide an index of cerebral perfusion. We studied the effects of hyperventilation, a known stimulus of cerebral vasoconstriction, on conjunctival oxygen tension (PcjO2) in six normal, healthy adults; arterial blood gases were simultaneously measured in four of these subjects. A 5-min period of hyperventilation to a Paco2near 20 torr resulted in a rapid and significant (p< .01) increase in systemic oxygen tension as measured by arterial blood gases and a transcutaneous oxygen monitor. These values gradually returned to baseline upon cessation of hyperventilation. PcjO2, near however, decreased significantly (p< .01) during hyperventilation, suggesting vasoconstriction of the conjunctival vascular supply. Because these changes temporally correlate with the cerebral vasoconstriction during hyperventilation, the conjunctival index of tissue oxygen tension may correlate with cerebral perfusion.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Pulmonary artery catheters are frequently used to measure pulmonary vascular pressures, particularly the pulmonary wedge pressure (Pw), which reflects pulmonary venous and ideally left atrial pressures. However, the pulmonary capillary pressure (Pc) is the major force in the formation of pulmonary edema. Unfortunately, Pw has been interpreted as being identical to Pc. In this study we used 7-Fr pulmonary artery catheters to measure effective Pc in closed-chest animals and patients. The decreasing pressure profile after pulmonary artery occlusion was separated into fast and slow components, with the inflection point between them representing Pc. Pc was also estimated by mathematically analyzing the curves in terms of a precapillary resistance, a large pulmonary capillary capacitor, and a postcapillary resistance.In dogs, Pc was determined after pulmonary vascular resistance had been increased by infusing serotonin and histamine. While Pw remained unchanged, serotonin increased pulmonary artery pressure (Ppa) 52% and Pc 16%, whereas histamine increased Ppa only 25%, but increased Pc by 35%. This is consistent with studies showing that serotonin primarily elevates precapillary resistance, and histamine increases postcapillary resistance.In thoracic surgery patients, Pc was not consistently related to Pw. This measurement was simple, reproducible, and provided a more precise capillary filtration pressure than Pw. It should be clinically useful in monitoring patients with pulmonary hypertension and adult respiratory distress syndrome, especially those with pulmonary artery catheters.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We report a series of 60 children with epiglottitis, 42 who were admitted via our emergency room and 18 who were transferred to Children's Hospital of Michigan (CHM) after initial airway management elsewhere. Patients managed entirely at CHM had lateral neck x-rays performed (diagnostic in each case), and underwent nasotracheal intubation in the operating room. There was no mortality or permanent morbidity in this group. Transferred patients were managed in a variety of ways at their referring institutions, sometimes without an artificial airway. Complications in this group included transient hypoxic encephalopathy (three children) and permanent severe encephalopathy (one child); four other children died. Blood cultures were positive forHemophilus influenzaetype b in 96% of the entire series. This study illustrates the importance of a consistent, well-organized approach to the diagnosis and management of epiglottitis, the reliability of a lateral neck x-ray, the high incidence ofH. influenzaebacter-emia, and the efficacy of nasotracheal intubation for maintaining airway patency in this disease.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

During this one-year prospective study, 61 (13.7%) of 444 patients admitted to the pediatric ICU at the University of Virginia Hospital developed nosocomial infections. By comparison, general medical/surgical ward patients had an overall 4.8% risk of acquiring an infection during their hospital stay. Patients who had prolonged ICU stays and those on plastic surgery, neurosurgery, and pediatric surgery services were more likely to become infected. The four bloodstream pathogens isolated in five episodes of hospital-acquired bacteremia wereStaphylococcus epidermidis, S. aureus, Escherichia coli, andSerratia liquifaciens.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Sixteen elderly postoperative patients were randomized in a crossover study comparing isocaloric volumes of 20% and 10% fat emulsions used for total parenteral nutrition (TPN). The caloric intake was maintained constant during the two 7-day periods of each infusion. The indices measured after each period were total volume of fluid administered, change in body weight, hematocrit, serum sodium, creatinine, albumin, blood urea nitrogen, glucose, inorganic phosphate, and cholesterol.The total volume of 10% isocaloric nutrient solution was significantly (p< .05) greater than that of the 20% solution. A rise in body weight and a fall in serum indices of hydration status were observed; five patients developed clinical signs of overhydration while on the 10% solution. These changes did not occur with the 20% solution. Thus, isocaloric substitution of a 20% fat emulsion for a 10% fat emulsion with TPN prevented overhydration and hemodilution without compromising nutrient intake.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

This study investigated the involvement of substances derived from arachidonic acid in the mechanism of endotoxin's protective action against pulmonary oxygen toxicity, Eighty-three percent of rats treated with a small dose of endotoxin (1 mg/kg) survived exposure to over 95% oxygen for 7 days. In contrast, all control rats exposed to the same oxygen concentration died within 3 days. When the endotoxin-treated rats were also treated with the soluble lysine salt of acetylsalicylic acid (100 mg/kg), 7-day survival decreased to 25%. This suggests that prostaglandin metabolism may play an important role in the protective action of endotoxin during hyperoxia.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To evaluate the effectiveness of high-frequency jet ventilation (HFJV) in the treatment of meconium aspiration, 28 puppies were assigned randomly to one of three ventilator techniques. After aspiration of 4 ml/kg of 20% meconium and baseline measurements on conventional ventilation (CV), the animals were ventilated for 6 h with either CV, HFJV, or HFJV combined with slow conventional ventilation (combined HFJV). Arterial and mixed venous blood gases, systemic and pulmonary arterial pressures, pulmonary capillary wedge pressure, and cardiac output were measured. Combined HFJV proved superior to the other two techniques, resulting in significantly better oxygenation and ventilation at a lower mean airway pressure (Paw). Oxygenation with standard HFJV was comparable to CV, producing Paw and Pco2values intermediate between those of CV and combined HFJV. There were no significant intergroup differences in cardiac output or the incidence of pneumothorax. Improved gas exchange was attributed to alveolar recruitment and prevention of atelectasis. Alteration of the distribution and/or clearance of meconium may also be important.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Mechanical ventilation at rapid rates may cause gas trapping by decreasing the time available for expiration. The volume of gas trapped within the lungs depends not only on the expiratory time, but also on the rate of emptying of the lungs. Because newborn infants are frequently ventilated at rapid rates, we examined the factors determining the rate of lung emptying, and thereby the development of gas trapping, at ventilatory rates of 40 to 120 breath/min in anesthetized and paralyzed rabbits. We found that flow and volume were related nonlinearly during the first segment of expiration, and linearly during the second segment. Only the second segment could therefore be described with a single time constant. The expiratory resistance of the respiratory system and endotracheal tube was up to 4.5 times greater than the inspiratory resistance, a finding explained by the higher transmural airway pressures during inspiration and by the dynamic effects of the increase in cross-sectional airway area at the junction of endotracheal tube and trachea. This high expiratory resistance lengthened the time constant of the second segment of expiration which, combined with the delay caused by the slow opening of the exhalation valve during the first segment, promoted gas trapping when the expiratory time was shortened.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID