摘要:

The alveolar to arterial oxygen pressure difference (AaDO2) and pulmonary venous admixture (Qs/Qt) were measured in 32 patients with chronic obstructive pulmonary disease during right heart catheterization at inspired oxygen concentrations (FIO2) of 21, 24, 28, 35, and 40%. Patients without chronic hypercapnia (PaCO2< 45 torr, group A) had Qs/Qt less than 25% while breathing room air; their AaDO2rose at a rate of 3 torr for each percent increase in FIO2. In those with chronic hypercapnia (PaCO2> 44 torr, group B), the Qs/Qt was always greater than 24% during air breathing and the AaDO2rose at a rate of 5 torr for each percentage increase in FIO2. These changes should be considered in the interpretation of the AaDO2in patients with COPD in whom the FIO2is changed during the course of therapy. The Qs/Qt fell curvilinearly with increasing FIO2but the rates of fall were quantitatively different in groups A and B. A physiological explanation for the changes in Qs/Qt and AaDO2which result from changes in FIO2is presented.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Twelve patients were treated prospectively for adult respiratory distress syndrome with diuresis and low levels (≤20 mm Hg) of positive end-expiratory pressure. Eight patients responded to diuretics and two to dialysis by an increase in static compliance of the respiratory system, improvement in arterial oxygen tension, and an increased urine output. Two patients did not respond with an improvement in these tests. Responses were transient and multiple doses were required to produce a sustained effect.Even with improvement of pulmonary function after treatment, the mortality was 67%, similar to that reported from other centers since 1975. Recently a new treatment protocol has been proposed that uses high positive end-expiratory pressure (≥20 mm Hg) early in the course of adult respiratory distress syndrome; mortality using this technique was 20%. The difference in survival may be more apparent than real since each center has a unique population of patients and time of initial therapeutic intervention. A randomized collaborative study comparing treatment protocols is needed.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

The effect of altered mechanical ventilation on the incidence of alveolar rupture and bronchopulmonary dysplasia (BPD) was reviewed in infants who had neonatal respiratory distress syndrome (RDS) (N = 99). From 1971 to 1974 we attempted to minimize pulmonary oxygen exposure. Accordingly, during the resolution of respiratory distress syndrome, the ventilator pressures were not reduced until the FIO2had been lowered to 0.4 (N = 61). In 1974 to 1975 earlier reduction of pressures was instituted as the FIO2was lowered to 0.6 or less (N = 38).Birth weight and gestational age were comparable in the two groups. With earlier reduction of ventilator pressures, there was a significant decrease in the duration of exposure to peak inspiratory pressures ≥40 cm H2O (p< 0.004) and ≥50 cm H2O (p< 0.02). The incidence of alveolar rupture during positive pressure ventilation fell from 51 to 24% (p< 0.015) and bronchopulmonary dysplasia from 41 to 13% (p< 0.003). In addition, there was a decrease in the duration of mechanical ventilation (p< 0.02) and exposure to an FIO2≥ 0.6 (p= 0.07).The results confirm the intimate relationship of pulmonary barotrauma, as reflected by the occurrence of alveolar rupture during positive pressure inflation of the lungs, to the subsequent development of bronchopulmonary dysplasia and that prevention of the former is associated with a concomitant fall in the incidence of the latter.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Studies of breathing patterns that use a mask (M) or mouthpiece plus noseclip (MP + NC) may contain artifacts due to the stimuli of the apparatus used. A canopy-spirometry-computer system was used to analyze respiratory patterns in a noninvasive manner. Changes in respiration induced by the application of M or MP + NC were analyzed.Twenty-two normal subjects and five critically ill patients were studied in (1) canopy alone, (2) canopy with M and (3) canopy with a MP + NC (in normal subjects only). An algorithm quantified each breath and determined tidal volume (VT), frequency (f), minute ventilation (V), O2consumption (VO2), CO2production (Vco2), sigh frequency (SF), ventilatory equivalent (VEco2defined as V/Vco2), and tidal volume distribution (VTD) VTD that reflects the tendency to breathe in a relatively narrow range of tidal volumes and is quantified as VTD10, VTD20(% breaths within ± 10% and ± 20% of mean VT).The M increased VT, V, VEco2(presumbly secondary to its increased dead space) VTD10and VTD20. MP + NC increased VT, V and decreased VTD10and VTD20. Neither device affected SF. The M produced similar changes in the resting ventilation of both the patients and normal subjects.Our previous studies have shown that ill patients breathe at relatively fixed VT, i.e., high VTD10and VTD20. Use of a M or MP + NC obscured this phenomenon and altered VT, V, and VEco2

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

In order to assess the immediate and long-term outcome of very low birth weight infants, a retrospective analysis of clinical and biochemical parameters of 100 consecutive newborns with birth weights

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

We reviewed the charts of 31 children receiving dopamine to document possible changes in cardiac rhythm associated with dopamine infusion. Six of these developed a dysrhythmia while on dopamine. All six were receiving dosages greater than 10μ/kg/min; in five of the six patients the infusion rate varied from 10–20 μ/kg/min. Of the remaining 25 patients, 14 had preexisting dysrhythmias of nonventricular origin. Two of these 14 patients converted to sinus rhythm while on dopamine. Eleven patients who were in preexisting sinus rhythm had no rhythm changes on dopamine. Based on the results of this study, we recommend that dopamine should be used cautiously in children in the dosage range between 10–20 μ/kg/min.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A method for continuous measurements of oxygen consumption (VO2) and cardiac output is described. This relatively inexpensive system was found to be practical for monitoring critically ill patients over the past 5 years. Clinical studies illustrating its usefulness are presented.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Most critically ill patients have a high catabolic rate to which sepsis, restlessness, and the hormonal stress response may be contributing factors. This has been confirmed by measurement of oxygen consumption. (Vo2) as a reflection of energy expenditure. While acutely ill patients may adapt to this situation, one of their adaptative mechanisms is to increase their minute ventilation. Increased minute ventilation increases the work of breathing and the oxygen cost of respiratory work. The higher the minute ventilation, the higher the percentage of oxygen consumed for respiratory work.In order to evaluate the magnitude of these factors, 20 acutely ill patients (severe burns, multiple injuries, and comatose states) were studied by measurements of Vo2during mechanical ventilation and after disconnection from the ventilator for short periods of time; i.e., 20 min. Paired tests, on and off ventilator, were performed successively three to five times on each patient ventilated for various reasons, but not those in respiratory distress. The tests were mainly performed during the period of weaning from mechanical ventilation. A reproducible increase in Vo2was observed in most patients when they were disconnected from mechanical ventilation and allowed to breathe spontaneously. The observed reduction of Vo2with mechanical ventilation was interpreted as a direct result of mechanical ventilation. The possibility of extending the indications for mechanical ventilation in hypercatabolic state patients without acute respiratory failure is discussed.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

At operation the body temperature of mechanically ventilated infants was initially decreased from 25 to 22°C with surface cooling and further lowered to 16°C by total body perfusion. During circulatory arrest, averaging 40 min, repair of complex intracardiac deformities was carried out. Rewarming to 36°C was achieved by 35–65 min of total body perfusion. Of 29 infants, 23 under 10 kg survived their correction; normothermic ventilation without added CO2was given throughout the cooling period. The following measurements were made: gas exchange, lung mechanics, heart rate, arterial pressure, right atrial pressure, cardiac output (Qt), ECG., core and nasopharyngeal temperature, as well as biochemical determinations. During surface cooling O2consumption (V02), CO2production (Vo2), endtital CO2(PETCO2) and PaCO2decreased proportionally and linearly with body temperature. Inspiratory resistance, total compliance, physiological dead space (VD/VT), and the single breath CO2curve did not reveal disturbed lung function. Mean arterial pressure was 98, 90, and 70 mm Hg and heart rate was 141, 107, and 76 beat/min, at temperature 35,30, and 25°C, respectively. Cardiac index was 2.2 ± 0.2 liter/min/m2(mean ± SEM,n= 25) 2 hours after surgery. Arterial lactate reached peak values of 4.1 ± 0.3 mM/liter (n= 17), during rewarming but returned to normal. Respiratory alkalosis caused by hyperventilation during cooling caused no apparent harm. No neurological damage was observed. It is concluded that surface cooling performed with normothermic ventilation under guidance of core temperature, Vo2, PETco2, and Vco2is a safe method.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

The right atrial pressure (PRA) was compared to the pulmonary capillary wedge pressure (PCW) in 54 patients. In patients with heart disease, the correlation of PRAwith PCWwas poor. However, in patients without clinical heart disease, PRAapproximated PCW, in both absolute number and change. This finding was independent of disease process or the presence of controlled mechanical ventilation.

ISSN:0090-3493    

出版商:OVID    

年代:1978

数据来源: OVID