摘要:

Coagulation, fibrinolytic, kallikrein, and complement systems were studied in 20 patients with multiple trauma. Three of four patients with a trauma score less than 10 on hospital arrival died, compared to one of 16 with a score over 10. Five patients developed disseminated intravascular coagulation. Signs of activated cas-cade systems were evident in most patients on hospital arrival. Changes were not related to trauma score, but patients with an arterial pressure below 110 mm Hg had significantly lower levels of antithrombin III and alpha2-antiplasmin than those with higher BP. This study confirms that the cascade systems are activated very soon after multiple trauma.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Twenty-seven low birth weight infants who developed pulmonary interstitial emphysema (PIE) and respiratory failure while on conventional ventilation were treated with high-frequency oscillatory ventilation (HFOV). The mean birth weight was 1.2 kg (range 0.55 to 2) with gestational age of 28 wk (range 25 to 34). Ten patients died, six of whom had documented sepsis with shock and were therefore excluded from analysis. All patients showed initial improvement on HFOV. Surviving patients showed continued improvement in oxygenation and ventilation at increasingly lower fraction of inspired oxygen and proximal airway pressure with resolution of PIE, while nonsurvivors progressively developed chronic respiratory insufficiency with continued PIE from which recovery was not possible. Overall survival in nonseptic patients was 80% (16 of 20). We found HFOV to be effective in the treatment of PIE and hypothesieze that interstitial airleak is decreased during HFOV because adequate ventilation is provided at lower peak distal airway pressures.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

External cardiac pacing is a recently reintroduced, effective method for emergency cardiac stimulation. The optimal electrode position and polarity for external pacing were determined in two groups of normal subjects. In six subjects there was no significant difference in pacing threshold when electrodes were positioned as follows: negative electrode in left parasternal region, positive electrode in right subscapular region; negative electrode in left parasternal region, positive electrode in left subscapular region; or negative electrode at cardiac apex, positive electrode in right parasternal region. In the remaining ten patients, pacing attempts were ineffective when electrode polarity was reversed. We conclude that exact electrode positioning is not crucial for external cardiac pacing, as long as the anterior or apical electrode is negative.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

In order to evaluate a new thoracic electrical bioimpedance (TEB) system for measurement of stroke volume based on the Sramek-Bernstein equation, 391 paired values of cardiac output were measured simultaneously with the standard thermodilution method. These values were obtained from 16 patients selected for having the most severe illness during a 6-month period; the intent was to evaluate the bioimpedance method in the worst possible situations. The correlation coefficient (r) was 0.83, slope was 0.87, intercept was 1.53, and the mean difference between the two methods was 16.2 ± 11.8 (SD)% in the total series. In 285 paired samples where satisfactory conditions were met, r was 0.90, slope was 0.98, intercept was 0.34, and the mean difference was 11.8 ± 8.9%. The data indicate satisfactory correlations between these two methods. When the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreement between serial thermodilution methods.Difficulties may arise with dysrhythmias, tachycardia (heart rate greater than 150 beat/min), metal in the chest or chest wall, sepsis, hypertension, and extremely oily skin. Mechanical ventilation did not appear to be a problem.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We examined the extracellular equilibrium status of two redox couplets normally found in plasma (lactatepyruvate [L-P], beta-hydroxybutyrate, and acetoacetate) during acute metabolic acidosis produced by muscle exertion. Both pre- and postexertion plasma spontaneously underwent loss of acetoacetate and gain of L when compared to the baseline values. Exercise further induced a 332% rise in L (p< .001) and a 102% rise in P (p< .001). The empirically derived ratio of equilibrium constants, KI.P/KBA, fell 50% (p< .001), and the calculated change in free energy (ΔF) fell from 3.6 to 3.1 kcal/mol (p< .001) after exercise. The changes induced by exertion were simulated closely by an in vitro model of a reduced state. Thus, the triad of a) inconstant metabolite concentrations, b) inconstant KI.P/KBA, and c) ΔF both inconstant and non-zero, indicates that there is no state of equilibrium for these metabolite couplets in human plasma. The KI.P/KBAratio appeared to reflect the degree of deviation from equilibrium and may therefore be useful when investigating altered redox states such as metabolic acidosis.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Clinical evaluation of metabolic acidosis has involved measurement of lactate (L), pyruvate (P), beta-hydroxybutyrate (BOHB), and acetoacetate (AcAc). We previously demonstrated that these metabolites are not at equilibrium in plasma. Their degree of disequilibrium is reflected in the ratio of apparent equilibrium constants (KLP/KBA) for the two redox couplets, L-P and BOHB-AcAc. The purpose of the study was to examine how well this ratio reflects disequilibrium in patients with metabolic acidosis. Measurements of the four metabolites were obtained in 23 critically ill patients. Disequilibrium was again observed, as manifested in an inconstant ratio (p< .01). The ratio increased with clinical improvement. Patients were more likely to die during their ICU stay if the estimated ratio was low, particularly if metabolic acidosis was present. Patients with respiratory acidosis had both intermediate probabilities of death and intermediate ratios when compared to inpatient controls (ICU patients without acidosis). Our data indicate that changes in the L-P-BOHB-AcAc cycle reflect the degree of metabolic derangement in critically ill patients.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We evaluated the influence of intrinsic positive end-expiratory pressure (PEEPi) on the measurement of static respiratory compliance in 15 adult patients with acute respiratory failure under mechanical ventilation. Modifying the inspiratory/expiratory ratio from 1:2 to 2:1, and the respiratory frequency from 15 to 20 and 25 breath/min significantly changed compliance values. Because PEEPi can increase the work of breathing, we suggest adjusting ventilatory variables to minimize PEEPi.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We observed prospectively 20 consecutive patients with severe hypomagnesemia (serum Mg 0.01 to 1.2 mg/dl [0.01 to 0.5 mmol/L], mean 0.8 mg/dl [0.33 mmol/L]) before and after correction with parenteral magnesium sulfate. Only three patients, all with hypocalcemia, had tremor and muscle twitching and none showed tetany, a positive Trousseau's test, arrhythmias, or ECG abnormalities. Moreover, review of the literature on hypomagnesemia did not justify attributing these clinical symptoms to hypomagnesemia.In a follow-up study of 111 consecutive serum samples from hypocalcemic patients, 36 (32%) indicated hypomagnesemia (serum Mg no greater than 1.5 mg/dl [0.6 mmol/L]); however, hypomagnesemia had been unsuspected in all but two patients. We conclude that hypomagnesemia rarely shows specific signs or symptoms; its diagnosis depends on a high index of suspicion in patients with hypokalemia, especially after its correction, and in patients with unexplained hypocalcemia.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effect of ventilation by high-frequency oscillation (HFO) on gas exchange in the abnormal lung is not well defined. In this study the efficiency of oxygenation by HFO (stroke volume 2.5 to 3.5 ml/kg, frequency 15 to 30 Hz) and by conventional mechanical ventilation (CMV) (tidal volume 15 to 20 ml/kg, frequency 8 to 15 breath/min) was compared in dogs with acute lung injury. Sixteen normal animals were studied under general anesthesia (halothane) on day 0 (control) and then injected intraperitoneally with 10 mg/kg of paraquat in divided doses over 3 consecutive days. Eight dogs were restudied on day 4 (moderate lung injury) and the other eight dogs on day 8 (more severe lung injury). With acute lung injury there was a progressive decrease in total lung capacity, decrease in lung compliance, and hypoxemia. In the moderate lung injury group, at equal alveolar ventilation, HFO resulted in a significant improvement in oxygenation (PaO295 to 104 torr) with a corresponding increase in mean lung volume when compared with CMV. In the severe lung injury animals, there were no significant differences in oxygenation or in mean lung volume between HFO and CMV.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The accuracy with which transcutaneous measurements of oxygen tension reflect Pao2in older infants has recently been questioned. We therefore examined the effects of maturation, i.e., age or skinfold thickness, on the accuracy of transcutaneous oxygen tension (Ptco2) and oxygen saturation (Stco2) measurements in 19 infants (age 1 to 61 wk) undergoing elective cardiac catheterization.Twenty-seven simultaneous arterial and transcutaneous measurements revealed a good correlation between Ptco2and Pao2(r = .91, slope .77, intercept 3.23 torr). The mean arterial-transcutaneous Po2difference of 10 torr (range −15 to 35) was independent of age but was significantly correlated with skinfold thickness (r = .45,p<.05). There was also a good correlation between Stco2and Sao2(r = .95, slope .65, intercept 27.8%). The mean arterial-transcutaneous oxygen saturation of 1.4% (range −17.3 to 14) was unaffected by age or skinfold thickness. However, neither Ptco2or Stco2measurements were accurate in patients with severe hypoxemia; Stco2consistently overestimated the Sao2when the Sao2was below 70%.Thus, in this study the discrepant Ptco2measurements in older infants were due to increasing skinfold thickness rather than age. Ptco2monitoring still has an important role in oxygen monitoring and together with Stco2provides valuable information on oxygenation.

ISSN:0090-3493    

出版商:OVID    

年代:1986

数据来源: OVID