摘要:

High frequency jet ventilation (HFJV) has been used hi recent years hi some forms of respiratory failure, where the presence of barotrauma limited the application of high peak inspiratory pressure. In the present report, the authors describe the clinical experience with 17 patients, who could not be supported with conventional mechanical support and were placed on HFJV. Rates of 100 breath/nun, inspiratory/ex-piratory ratio of 1:2 and cannula size of 1.06–1.62 mm (18–14) gauge were used. Driving pressure required to maintain a Paco2 of 40–45 torr was 14–45 psig; however, except in 2 patients who developed hemorrhagic tracheitis with subtotal obstruction of both mainstem bronchi, a driving pressure higher than 27 psig was never required, even when PEEP up to 32 cm H2O was used. Of 17 patients treated, 8 survived. In all cases, alveolar ventilation could be maintained within the desired range with high frequency ventilation, even in those patients who eventually died; mechanical support never provided better oxygenation or alveolar ventilation than high frequency ventilation. Hemodynamic function was essentially unchanged with high frequency ventilation; indeed, hi three cases, motropic support with dopamine could be discontinued after initiation of high frequency ventilation.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

After administration of monocrotaline to dogs to produce noncardiogenic pulmonary edema, one-half of the animals (controls) were treated with intermittent positive pressure breathing (IPPV), and one-half with that ventilation plus the addition of 10 cm H2O of positive end-expiratory pressure (PEEP). After 6 h, the animals treated with PEEP demonstrated significantly better arterial oxygenation and reduced AaDO2, but lung water, quantitated either postmortem or in vivo by indicator-dilution techniques, was no less than controls. Although PEEP improves gas exchange, it fails to modify the degree of pulmonary edema present.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

This study evaluates the effectiveness of combining mechanical ventilation and 5 cm H2O positive end-expiratory pressure (PEEP) at the onset of adult respiratory distress syndrome (ARDS) in dogs. Five cm H2O PEEP applied at the onset of ARDS in oleic acid injured dogs resulted in a decrease in cardiac output (CO). This decrease was accompanied by beneficial effects including a relatively stable Sao2 and Pao2. Control group dogs (receiving mechanical ventilation only) showed a less dramatic change in CO, but demonstrated a dramatic drop in saturation, compromising oxygen transport to the tissues. Thus, despite decrease in CO experienced by the PEEP group, oxygen extraction at the tissue level remained high.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The object of this paper was to evaluate the effect of a continuous dopamine infusion (10–12 μg/kg·min) on the estimated hepatic blood flow (EHBF) and cardiac output (CO) in man. Measurements were made in 3 periods: the initial control state, during dopamine infusion, and after the infusion.The CO (by thermodilution) and EHBF (by hepatic vein sampling after continuous indocyanine green (ICG) infusion) were measured during each phase. Ten subjects, with inapparent hepatic disease, hemorrhage, or hemodynamic anomalies, were studied. The results showed a 64% increase in the EHBF and a 49% increase in the CO. All subjects showed a return to the original baseline state after infusion.The EHBF/CO was 14% in the control period, 17.3% during infusion, and 13.4% after dopamine infusion. These changes were not statistically significant. Dopamine, therefore, increased both EHBF and CO, but the existence of intrahepatic dopaminergic receptors could not be established.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The effect of an acute 25% decrease in mean arterial pressure (MAP) produced by sodium nitroprusside (SNP) infusion on mean intracerebral and cerebral perfusion pressures was examined in 7 swine with intracranial hypertension. All animals were anesthetized (a-chloralose), paralyzed (pancuronium bromide), orotracheally intubated and mechanically ventilated to maintain normocapnia. An epidural balloon was incrementally inflated to produce the desired brain tissue pressure (BTP) which was measured by an intracerebral microtransducer implanted contralat-eral to the balloon. MAP was measured from the carotid artery; cerebral perfusion pressure (CPP) was calculated as: MAP - BTP. During mildly (14 ± 1 (se) mm Hg) or moderately (37 ± 3 mm Hg) increased BTP, SNP infusion further increased BTP (17 ± 1 and 44 ± 3 mm Hg, respectively) (p < 0.05). During severely increased BTP (70 ± 4 mm Hg), SNP decreased BTP (53 ± 4 mm Hg, p < 0.05). Despite this variable BTP, CCP consistently decreased during SNP infusion. BTP and supratentorial subarachnoid cerebrospinal fluid pressure correlated closely; however, the supratentorial subarachnoid pressure consistently underestimated BTP. These findings suggest that estimation of BTP obtained from subarachnoid screw-type devices may not accurately record the pressure within cerebral tissue and the SNP should not be administered to patients with known or suspected intracranial hypertension unless an intracranial (either BTP or subarachnoid) pressure is being monitored.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The administration of albumin in the initial resuscitation of shock remains highly controversial. Impaired coagulation in the critically injured patient has recently been added as an argument against the use of supplemental albumin. This study investigated the hemostatic effects of albumin therapy after hemor-rhagic shock. Twenty mongrel dogs were bled to a systolic pressure of 60 mm Hg for 1 h. After the return of shed blood, the animals received either lactated Ringer's solution or 5% serum albumin (25 ml/kg) daily for the 3 days. Coagulation parameters were measured before bleeding, immediately after resuscitation, and on days 2, 3, and 4.The changes in platelet count, platelet function, and serum fibrinogen were similar in the albumin treated and control animals. Although the prothrombin time and partial thromboplastin time were more prolonged in the albumin group, the changes were not sufficient to produce clinical bleeding.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Hemodynamics, pulmonary diffusing capacity (DLco) blood gases, oxygen consumption (Vo2) and carbon dioxide excretion (Vco2) were studied in healthy volunteers and ventilator-treated, critically ill patients before and during infusion of lipid emulsion for 4 h. Triglyceride levels rose from 1.0 mmole/L to 8.5 mmole/L in the volunteers and from 1.4 mmole/L to 6.3 mmole/L hi the patients after 4 h. No adverse effects on cardiovascular performance were observed. Increases in Vo2, and Vco2 and cardiac output were found m both groups, while RQ remained constant. No changes hi DLco and blood gases occurred.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Arterial (Paco2), alveolar (Paco2), mixed expired (Peco2) CO2 pressures, CO2 production (Vco2) as well as arterial O2 saturation (Sao2) were measured on 20 severely hypoxic and hypercapnic patients breathing air (A) and 100% O2 (HO). On HO, mean Paco2 increased to 56.6 torr from 50.8 torr on A, whereas there was no significant change in Paco2 (38.3 on A, 38.6 on HO), so that the arterial-alveolar gradient (aADCO2) increased from 12.5 to 18.0 torr. Peco2 remained essentially the same. There was a statistically significant correlation between the increase in Paco2 on HO and the arterial unsaturation (100 - Sao2) on A and also between Paco2 on A and its increment on HO. When the rise in Paco2 and aADCO2 were estimated which resulted from the shift in the Co2 dissociation curve due to complete oxygen-ation of hemoglobin on HO (Haldane effect), 78% of the observed change in Paco2 could be accounted for. The deadspace/tidal volume ratio (Vd/Vt) increased from 0.59 on A to 0.64 on HO and 87% of this difference could be attributed to the Haldane effect. The results emphasize the importance of considering this effect when interpreting alterations in Paco2, aADCO2 and Vd/Vt on transition from air to hyper-oxia, particularly in patients with severe hypoxemia and hypercapnia.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The course of idiopathic respiratory distress syndrome (IRDS) treated with continuous positive airway pressure (CPAP) was studied in 38 infants with a respiratory index (RI) based on AaDO2 and Po2 measurements. Thirteen infants were treated with early CPAP (Fio2= 0.3, Po2 > 50 torr (6.7k Pa)) at a mean age of 7.1 h and 25 infants received late CPAP (Fio2 = 0.5, Po2 > 50 torr) at a mean age of 15.1 h. Significant differences were demonstrated between the two groups in duration of CPAP (42 versus 72 hours) peak RI (3.7 vs. 6.7), time to peak RI from start of therapy (10.0 versus 19.4 h), number of infants ventilated (0 versus 5) and number of air leaks (0 versus 3).The rate of disease worsening as measured by changes in Rl/h before CPAP and after CPAP initiation was comparable in the respective treatment groups.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The present experiments were designed to simulate postoperative shock in 145 Wistar rats by exteriori-zation of the intestine in wet gauze and occluding completely the superior mesenteric vessels with a rubber clamp. After 1 h, the clamp was removed, the intestine was returned to the abdominal cavity and the abdomen closed. Two sets of experiments were undertaken. First, in order to study plasma volume loss after untreated shock, animals were sampled for he-matocrit and organ weights. Also, plasma volume loss during this shock after single infusions during 10 min of various fluids was assessed using hematocrit change as a measure of plasma loss.Second, on the basis of the results from the first set of experiments, the relative effectiveness of colloids (albumin, dextran 70, and dextran 40) and one electrolyte solution (Ringer's acetate) was evaluated in rats subjected to the intestinal shock using the survival rate as the criterion. The agents were given in volumes needed to maintain similar hemodilution during 4 h. In untreated rats, hematocrit increased from 51.7 ± 3.0 (sd) to 65.7 ± 3.5% at 6 h after return of the intestine, and then gradually decreased to preshock values after 24 h. Concomitantly, the weight of the exteriorized intestine increased from 6.5 ± 0.5 g/100 g of body weight (bwt) to 10.7 ± 1.5 g at 6 h after shock; the survival rate at 24 h was 29%. Large volumes of fluids were required initially in order to maintain hemodilution. Ringer's acetate in volumes of 71–118 mg/100 g of bwt were given to obtain hematocrit at the preshock level, but there was no improvement in 24 h survival rate after Ringer's acetate. Colloids of 3.5% concentrations hi volumes between 19–24 ml/100 g bwt maintained hematocrit at about > during 4 h and resulted hi 72% survival rate at 24 h. Animals infused with Ringer's acetate gained 44–59% in weight versus 9–11% in rats given colloids. It is concluded that shock associated with plasma volume loss and hemoconcentration is best resuscitated with colloid containing fluids at a rate determined by the degree of hemodilution.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID