The effects of short periods of high pulmonary vascular pressures on the filtration characteristics of the lung's microcirculation have been studied in isolated dog lungs. When left atrial pressures (Pla) were less than 30 cmH2O, the capillary filtration coefficient (Kf,c) was not different from that of controls (0.192 +/- 0.009 ml X min-1 X cmH2O-1 X 100 g-1). In 17 of 23 observations, where Pla exceeded 55 cmH2O, Kf,c was at least 1.5 times control. In 10 of 13 lungs, Kf,c returned to control values within 2 h after the Pla increase. However, in the other three experiments, Kf,c did not return to control values. These findings indicate that the filtration coefficient of pulmonary microvessels increases at high left atrial pressures (greater than 55 cmH2O) and may represent either a "stretching" of existing pores or opening of a few large pores.

Animals↗

PubMed1984

Increased microvascular permeability in dog lungs due to high peak airway pressures.

The effect of peak airway pressure (Paw) on vascular permeability and the "safety factor" against edema formation was determined in isolated blood-perfused lower lobes of dog lungs. Microvascular permeability was evaluated using the measured filtration coefficient (Kf,C), isogravimetric capillary pressure (Pc,i), and critical capillary pressure (Pcrit) for exhaustion of tissue safety factors. Airway pressure was maintained constant at -3 cmH2O except for the test period of 20 min when the lungs were ventilated at 6/min with sufficient volume to generate a peak inflation pressure ranging from 5 to 60 cmH2O. Mean Kf,C (in ml X min-1 X cmH2O X 100 g-1) were measured before and immediately after the period of peak airway pressures. Kf,C was significantly increased in all lungs where Paw exceeded 42 cmH2O, but in only two experiments at a lower Paw. Mean Pc,i was significantly reduced from control in the 45-55 and 55-65 cmH2O Paw groups, and both Pc,i and Pcrit were found to be inversely related to Kf,C measured after Paw ventilation. These data indicate that ventilation with Paw above 42 cmH2O (30.9 Torr) and in some cases lower pressures for 20 min significantly increased capillary hydraulic conductivity, reduced the effective osmotic effect of plasma proteins at the capillary wall, and reduced the total tissue safety factor against edema formation.

Animals↗

PubMed1983

Impact of a maternal transport program on a newborn service.

We reviewed the maternal transfers for one year (1980) to the Emory Perinatal Center, a tertiary care center for North Georgia. Of 445 telephone consultations or patient referrals, 150 women gave birth at the tertiary center. Indications for maternal transfer were predominantly based on the needs or anticipated needs of the fetus. There were a total of 163 births, 10 of them stillborn and 153 live-born. Three infants expired in the delivery room. Sixty infants (40%) required 580 days of intensive care. A total of 1,439 days of care in the intermediate unit was required and 1,077 days of care in other areas of the nursery. Adjusting these figures for a 0.8 occupancy rate revealed that two intensive care beds, 4.9 intermediate care beds, and 3.6 minimal care beds were required for just these maternally transported infants. Maternal transfers will result in a disproportionate increase in the workload of a nursery because of the immaturity and small size of these infants. When considering a maternal transfer service, appropriate planning must be made to meet the special needs of both the infants and their mothers.

Birth Weight↗

PubMedDate not supplied

Stereotypic movements after lorazepam administration in premature neonates: a series and review of the literature.

Explore the source record for details and available documents.

Dyskinesia, Drug-Induced↗