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Biomedical subjects

E Bancalari

Publications and source records attributed to E Bancalari.

At least 127 records · Page 7Linked to original sources
PubMed1984

Cardiovascular changes in group B streptococcal sepsis in the piglet: response to indomethacin and relationship to prostacyclin and thromboxane A2.

Seventeen piglets were infected with a continuous intravenous infusion of live group B beta-hemolytic streptococci (GBS). Hemodynamic changes were recorded, and blood samples were drawn for measurement of thromboxane B2 (TxB2) (stable metabolite of thromboxane A2) and 6-keto-PGF1 alpha (stable metabolite of prostacyclin). Control animals (n = 9) received only bacteria, while treatment animals (n = 8) received indomethacin, 3 mg/kg IV, 15 min after the start of the bacterial infusion. Control animals responded to the bacteria within 15 min with marked elevation in mean pulmonary artery pressure (Ppa) from 15 +/- 8 to 39 +/- 6 mm Hg and decline in PaO2 from 80 +/- 11 to 51 +/- 6 mm Hg and cardiac output (CO) from 0.24 +/- 0.07 to 0.13 +/- 0.07 liters/min/kg. Mean arterial blood pressure (AoP) significantly decreased from baseline value of 95 +/- 13 to 51 +/- 32 mm Hg by 180 min. In animals treated with indomethacin, these changes were reversed or significantly attenuated. The hemodynamic changes were associated temporally with elevations in plasma concentrations of TxB2 or 6-keto-PGF1 alpha. In the first 60 min, TxB2 levels in both groups correlated with Ppa (r = 0.72, p less than 0.001) and PaO2 (r = -0.60, p less than 0.001). A strong negative correlation between TxB2 and CO was observed over the first 180 min (r = -0.73, p less than 0.001). There was a statistically significant correlation between AoP and 6-keto-PGF1 alpha concentration between 60 and 180 min (r = -0.54, p less than 0.002). Indomethacin improved the hemodynamic function in this model of GBS sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1984

The effect of calcium antagonists on hypoxic pulmonary hypertension in the piglet.

Cardiovascular responses to the calcium antagonists verapamil and nifedipine were evaluated in a piglet model of hypoxic pulmonary hypertension. All animals were mechanically ventilated and paralyzed. Cardiac output (CO), pulmonary artery (Ppa) and aortic blood pressure (AoP), pulmonary wedge pressure, right atrial pressure (Pra), and arterial blood gases were measured prior to and after pulmonary hypertension was induced by hypoxia and after administration of calcium-blocking agents. Results were compared to a control group of piglets subjected to a similar period of hypoxia. Verapamil infusion (0.15 mg/kg) resulted in a rapid decrease in Ppa, AoP and pulmonary vascular resistance (p less than 0.05) which returned to baseline values by 15 min. Nifedipine (100 micrograms/kg) resulted in a decrease in Ppa at 1 min (p less than 0.05) which remained significantly lower than controls throughout the study period. AoP declined precipitously during the same time period (p less than 0.01). No significant change in Ppa was noted when nifedipine was administered at a dose of 10 micrograms/kg. For the most part, these drugs have a transient vasodilatory action on pulmonary as well as systemic circulation in this animal model; however, they might in higher doses be associated with significant systemic hypotension. For this reason, the use of these drugs in the treatment of hypoxic pulmonary hypertension in the neonate should be approached with caution.

Animals↗
PubMed1984

Apnea of prematurity: I. Lung function and regulation of breathing.

It has been suggested that apnea of prematurity may be caused by "immaturity" of central control of breathing. To test the validity of this hypothesis tidal volume (VT), alveolar ventilation (VA), alveolar Pco2 (Paco2), esophageal pressure change, and the slope of the CO2 response curve (delta Ve [minute ventilation]/delta Paco2) were determined in 18 infants with apnea (mean of 32 episodes of more than 20 seconds duration per day) and in 18 healthy newborns used as control subjects. The infants were matched for birth weight (1,068 g v 1,065 g), gestational age (30.2 weeks v 30.2 weeks), and postnatal age (8.6 days v 8.3 days). The results were as follows: Vt (4.4 +/- 1.0 mL/kg v 5.3 +/- 1.6 mL/kg), Va (96 +/- 21 mL/kg/min v 129 +/- 33 mL/kg/min), Paco2 (45.4 +/- 8.5 mm Hg v 35.6 +/- 4.7 mm Hg), esophageal pressure change (4.5 +/- 0.9 cm H2O v 6.0 +/- 1.8 cm H2O), delta Ve/delta Paco2 (20.2 +/- 10.6 mL/min/kg/mm Hg CO2 v 40.7 +/- 19.9 mL/min/kg/mm Hg CO2). There was a significant difference between infants with and without apnea for all measurements. The results indicate a decreased respiratory center output and a depressed ventilatory response to CO2 in infants with apnea. As there was no difference between the two groups in pulmonary mechanics or oxygenation, the findings support the hypothesis that a central disturbance in regulation of breathing is the cause of apnea in these infants.

Apnea↗
PubMed1984

Apnea of prematurity: II. Respiratory reflexes.

Airway obstruction is a cause of apnea in preterm infants. The activity of protective respiratory reflexes was determined in 18 preterm infants with apnea (mean of 32 episodes of more than 20 seconds duration per day) and in 18 neonates without apnea used as control subjects. This was done in order to elucidate the role of respiratory reflexes in apnea of prematurity. The infants were matched for birth weight (1,068 g v 1,065 g), gestational age (30.2 weeks v 30.2 weeks), and postnatal age (8.6 days v 8.3 days). The airway occlusion technique was used to determine the inspiratory prolongation of the occluded breath and the effective elastance of the respiratory system. Inspiratory prolongation is a measure for the reflex influence on inspiratory duration, and effective elastance reflects load compensating ability. Inspiratory prolongation was 7.3% +/- 33.5% in infants with apnea and 30.6% +/- 22.7% in the control group (P less than .025). Effective elastance was 1.1 +/- 0.5 cm H2O/mL in the apneic group and 1.5 +/- 0.5 cm H2O/mL in the infants without apnea (P less than .025). The results indicate that during exposure to respiratory loads, the infants with apnea maintained inspiratory effort poorly and had a decreased ability for load compensation. Their respiratory reflexes were significantly more immature than the reflex activity of the infants without apnea. This functional immaturity of respiratory reflexes may be a contributing factor in the etiology of apnea of prematurity.

Air Pressure↗
PubMed1983

Limitation of pulsatility index as a diagnostic tool in the newborn.

Pulsatile flow in the anterior cerebral arteries was studied and pulsatility index (PI) calculated by 3 observers in 10 newborn infants in order to establish the reproducibility of a noninvasive Doppler technique. No significant differences were noted among the observers and the estimated error of observation was 0.073. Subsequently, 14 healthy preterm infants were studied daily by a single observer in an attempt to establish a normal range of PI for prematures in the first 5 days of life. The babies were concomitantly studied with serial ultrasound examinations to rule out intracranial hemorrhage. The study revealed good interobserver reliability but wide variation of PI in normal, healthy premature infants with values falling within abnormal ranges previously described in asphyxiated infants or those with intraventricular hemorrhage (IVH). Caution is advised in using the PI to predict outcome.

Cerebral Arteries↗
PubMed1983

Effects of aminophylline on respiratory center and reflex activity in premature infants with apnea.

Fourteen preterm infants with apnea (body weight, 1052 +/- 44 g; gestational age, 30.2 +/- 0.5 wks; and postnatal age, 9.9 +/- 1.5 days) were studied in an effort to evaluate the effects of aminophylline on respiratory center output and respiratory reflex activity in the preterm infant with idiopathic apnea. This was done by using the airway occlusion technique. The infants were studied before and 48 h after aminophylline was begun as a treatment for apnea. Occlusion pressure, which reflects respiratory center output, was measured at 100 msec after occlusion started (P100) and at its maximum (Pmo). P100 increased from 2.4 +/- 0.2 to 3.1 +/- 0.2 cmH2O (P less than 0.005), and Pmo from 6.1 +/- 0.7 to 8.8 +/- 1.0 cmH2O (P less than 0.001) after aminophylline therapy was started. The % prolongation of inspiratory time during the occluded breaths, when compared to the unoccluded breaths increased from 26.2 +/- 10.6 to 55.8 +/- 12.5% (P less than 0.01). This reflects a significant increase in the strength of the Hering Breuer reflex. Effective elastance, a measure of respiratory load compensation, was significantly higher during aminophylline treatment. It increased from 1.09 +/- 0.14 to 1.33 +/- 0.14 cmH2O/ml (P less than 0.02).

Aminophylline↗
PubMed1982

Components of effective elastance and their maturational changes in human newborns.

The newborn's ability to compensate for a sudden increase in respiratory load remains unclear. The mouth occlusion pressure (Pmo) and the effective elastance (E'rs) were determined in 58 neonates ranging in gestational age from 28 to 41 wk. These results were compared with the esophageal pressure change (delta Pes) and with lung elastance (EL) obtained during regular breathing. Since E'rs = Pmo/delta Pes X EL, E'rs is proportional to an active component, Pmo/delta Pes and a passive component, EL. Although EL is 1.10 +/- 0.31 (mean +/- SD) cmH2O/ml at 28 wk gestation, this value decreases to 0.20 +/- 0.04 cmH2O/ml at full-term. The active component Pmo/delta Pes changes in the opposite direction. It is 0.92 +/- 0.25 at 28 wk gestation, indicating that there is no load compensation in the very premature infant. It increases to 2.06 +/- 0.50 in the full-term newborn, reflecting a linear increase in the ability for load compensation with advancing gestational age. The E'rs is largely determined by EL and is, therefore, not a good measure to compare load compensating ability. The quotient Pmo/delta Pes, being independent of tidal volume, lung maturation, and growth, reflects load compensating activity better than E'rs.

Compliance↗
PubMed1981

Maturational changes of reflexes influencing inspiratory timing in newborns.

Premature infants have frequent apneic spells, which in some cases are triggered by airway obstruction or increase in respiratory load. The response of the preterm infant to increased respiratory loads has not been adequately studied. Utilizing the airway occlusion technique, we determined the percent prolongation of the occluded, compared with the preceding unoccluded breath, in 58 newborns (gestational age 28-41 wk) during the first days of life. A significant correlation was found between gestational age and percent prolongation of inspirations (r = 0.76). At 29 wk gestation, prolongation was zero and increased up to 55% at term. The low mean prolongation obtained in the very premature infants can be explained by the large number of these infants who responded with shortening of their inspiratory time during airway occlusion. The response may be secondary to the intercostal phrenic inhibitory reflex, which inhibits inspiration when distortions of the chest wall occur. The shortening of inspiration during airway occlusion in many premature newborns reflects their inability to tolerate respiratory loads and may contribute to the high incidence of apnea in these infants. The progressive increase in prolongation with gestational age reflects the maturation of the respiratory system toward the more stable respiratory function of the full-term neonate.

Gestational Age↗
PubMed1980

Acute effects of albumin infusion on blood volume and renal function in premature infants with respiratory distress syndrome.

The purpose of this study was to determine the acute effects of albumin infusion on blood volume and renal function in preterm infants with RDS and low total serum protein values. Ten infants (gestational age 28 to 36 weeks, body weight 0.88 to 2.46 kg) were given albumin 1 gm/kg (as 25% iv solution) over a ten-minute period. Within ten minutes after infusion was completed, total serum protein concentration, colloid osmotic pressure, and blood volume rose significantly while hematocrit fell from their preinfusion levels (P < 0.0005). Mean arterial blood pressure showed a smaller and less clear-cut increase (P < 0.05). Creatinine clearance rose significantly with infusion; even though preinfusion clearances correlated poorly with gestational age (r = 0.43), postinfusion clearances correlated well (r = 0.92). No significant rises in urinary flow rate Uosm/Posm, or free-water clearance were observed. These results indicate that albumin infusion acutely increases both blood volume and glomerular filtration in premature infants with RDS.

Albumins↗
PubMed1980

Chestwall compliance in full-term and premature infants.

Chestwall compliance was determined in 26 premature infants (BW 1 320 +/- 410 g, gest. age 32 weeks) and in 10 full-term infants (BW 3 155 +/- 810 g) who were ventilated mechanically. Chestwall compliance in premature infants was 6.4 ml/(cmH2O X kg), decreasing with advancing gestational age to 4.2 ml/(cmH20 X kg) in full-term infants. There was a linear correlation (r = 0.95 and 0.79 respectively) between tidal volume and the pressure transmitted to the esophagus throughout the tidal volume range. The protion of airway pressure transmitted to the infants with hyaline membrane disease, 12% in newborns with a patent ductus arterisus, 17% in normal prematures and 25% in normal full-term infants. The findings suggest that during mechanical ventilation the high chestwall compliance and low lung compliance of premature infants prevent a significant rise in intrapleural pressure which could interfere with central venous return and cardiac output. However, using high inspiratory pressures and continuous distending airway pressure in the absence of lung pathology may result in a decreased cardiac output. The highly compliant chestwall of the premature infant may exert insufficient outward recoil and might be one of the causes of a low functional residual capacity and chronic pulmonary failure in the premature infant.

Compliance↗
PubMed1980

Lung compliance in newborns with patent ductus arteriosus before and after surgical ligation.

Pressure volume curves of the lungs were determined in 10 premature infants (mean gestational age 31.4 weeks, mean birth weight 1,260 g) before and after surgical ligation of a patent ductus arteriosus (PDA). 7 infants who had low compliance initially showed a significant improvement in lung compliance after surgery, while 3 infants whose compliance was close to normal before surgery had a decrease after ligation. In conclusion, a PDA with left to right shunt is frequently associated with a decrease in lung compliance that improves after ligation. Measurement of lung compliance in infants with PDA can be helpful in predicting the degree of improvement in lung function that may result from the closure of the ductus.

Ductus Arteriosus, Patent↗
PubMed1980

Normal pulmonary vascular resistance and left ventricular hypertrophy in young infants with bronchopulmonary dysplasia: an echocardiographic and pathologic study.

To evaluate the cardiac anatomy and functional hemodynamics in young infants with chronic lung disease, nine patients, aged 2 to 7 months, with a clinical diagnosis of bronchopulmonary dysplasia (BPD) underwent echocardiographic examination. All infants required supplemental O2 (mean FIO2 35%) to maintain adequate systemic oxygenation (Pao2 greater than 50 mm Hg). None of the infants had evidence of a patent ductus arteriosus at the time of examination. Echocardiographic measurements of left and right ventricular systolic time intervals revealed normal systolic time interval ratios suggesting pulmonary vascular resistances. However, echocardiographic evidence of left ventricular hypertrophy was found in eight of the nine infants, while right ventricular anterior wall thickness and right ventricular diastolic dimensions were not increased. Two infants died; marked left ventricular hypertrophy was noted at the time of postmortem examination while the right ventricular wall thickness was normal. The findings of left ventricular hypertrophy led to a retrospective review of autopsy material of seven patients who died with BPD over the past year. In six of seven cases examined, left ventricular posterior wall thickening was noted (range 7 to 11 mm); while the right ventricular wall thickness was normal (range 2 to 5 mm). These data suggest that (1) as assessed by echocardiography, the pulmonary vascular resistance is not significantly elevated in young infants with BPD, and (2) a hypertrophic left ventricle evolves which may assume importance in the pathogenesis of pulmonary edema in BPD, though the precise etiology remains undetermined.

Bronchial Diseases↗
PubMed1979

Hyaline membrane disease. Comparison of continuous negative pressure and nasal positive airway pressure in its treatment.

The effectiveness of continuous negative pressure (CNP) and nasal continuous positive airway pressure (CPAP) in the treatment of hyaline membrane disease and the incidence of complications were compared in 36 preterm infants randomly treated with CNP or nasal CPAP. Both methods of treatment were effective in increasing PaO2 and allowing a decrease in inspired O2 concentration. The time required with mechanical assistance and with an O2 concentration of more than 40% was equal in both groups. In the CNP group, four infants required mechanical ventilation because of clinical deterioration whereas in the nasal CPAP group, seven needed this type of therapy. Three infants in each group had extraalveolar air, and two patients in each group died. The results suggest that both methods of applying continuous distending airway pressure are effective. Nasal CPAP has the advantages of easier application and better access to the infant.

Blood Pressure↗