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Biomedical subjects

E Bancalari

Publications and source records attributed to E Bancalari.

At least 91 records · Page 5Linked to original sources
PubMed1989

Pulmonary function in preterm infants whose lungs were ventilated conventionally or by high-frequency oscillation.

To test the hypothesis that high-frequency ventilation may reduce the risk of barotrauma and thus the incidence of chronic pulmonary damage in preterm infants who need mechanical ventilation, we measured lung function before discharge in 53 infants who needed mechanical ventilation on the first day after birth and were randomly assigned to receive intermittent mandatory ventilation (n = 26) or to receive high-frequency oscillatory ventilation (n = 27). There were no significant differences between the groups in birth weight (mean +/- SD: 1010 +/- 240 vs 1030 +/- 230 gm), gestational age (29.1 +/- 2.0 vs 28.9 +/- 2.1 weeks), initial ventilatory support (mean airway pressure 7.2 +/- 1.8 vs 8.1 +/- 2.1 cm H2O; FiO2 0.62 +/- 0.24 vs 0.75 +/- 0.22), duration of mechanical ventilation (median (range): 6 (1 to 61) vs 10 (1 to 50) days) and duration of oxygen therapy (13 (1 to 109) vs 27 (4 to 227) days) for the intermittent mandatory ventilation group and the high-frequency oscillatory ventilation group, respectively. At the time of testing, weight was 1830 +/- 340 vs 1830 +/- 290 gm, and age was 68 +/- 24 vs 70 +/- 31 days. Respiratory flows were determined by pneumotachygraphy, esophageal pressure through a water-filled feeding tube, and functional residual capacity by N2 washout. Both groups had abnormal lung function with decreased lung compliance (1.65 +/- 0.51 vs 1.54 +/- 0.36 ml/cm H2O) and elevated pulmonary resistance (102 +/- 24 vs 107 +/- 36 cm H2O/L/sec). Functional residual capacity was in the normal range (30.6 +/- 6.0 vs 28.2 +/- 10.7 ml) in both groups. There were no significant differences in lung function between the two treatment groups. These results do not support the hypothesis that high-frequency oscillatory ventilation reduces the risk of lung damage in preterm infants.

Female↗
PubMed1989

Comparison of dynamic and static measurements of respiratory mechanics in infants.

The objective of this study was to compare the conventional method of measuring respiratory mechanics, which requires the passage of an esophageal tube, with the occlusion technique, which is less invasive. Thirty-nine preterm infants who received mechanical ventilation on the first day were studied before discharge (mean +/- SD: postnatal age 67 +/- 23 days; weight 1790 +/- 300 gm), and 27 of them again at 1 year (weight 8.1 +/- 1.4 kg). Flows were measured through a nosepiece by pneumotachometry, tidal volume by integration of flow, esophageal pressure through a water-filled tube, and airway pressure directly at the nasal piece. Airway occlusion was performed at the end of inspiration, and the following relaxed exhalation was analyzed to give compliance (Crs) and resistance (Rrs) of the respiratory system. These values were compared with dynamic lung compliance (Cdyn) and expiratory resistance (Re) of the previous unoccluded breath. In the younger infants, dynamic and static measurements did not differ significantly and were well correlated (Cdyn/Crs, r = 0.91; Re/Rrs, r = 0.95). In the older infants, Crs was 80% of Cdyn (p less than 0.001), and Rrs was 24% higher than Re (p less than 0.001). The measurements were well correlated (Cdyn/Crs, r = 0.94; Re/Rrs, r = 0.91). The regression line Cdyn versus Crs had a slope (0.77) significantly less than 1; the regression Re versus Rrs had an intercept (13.8) significantly greater than zero. The lower Crs and higher Rrs values can be expected because the static determinations include the chest wall. In the more immature infants, the very compliant chest wall, in combination with an underestimation of Cdyn because of the higher breathing frequency of these infants, may obscure this difference. We conclude that the occlusion technique gives accurate and reproducible results, is easily applied, does not need the passage of an esophageal tube, and is well tolerated by the infants.

Acute Disease↗
PubMed1988

Effect of distal endotracheal bias flow on PaCO2 during high frequency oscillatory ventilation.

In order to evaluate the effect of distal endotracheal bias flow during HFOV on PaCO2 we studied adult rabbits with normal lungs and those who had meconium-induced lung dysfunction. Animals were studied while 1.0, 1.4 and 1.8 ml/kg tidal volumes (VT) were delivered by a high frequency oscillator. In animals with normal lungs and a 1.0 liter/min distal bias flow, the PaCO2 decreased significantly (p less than 0.01) with all VT used. In animals with meconium instillation the decrease in PaCO2 was also significant (p less than 0.05) at all combinations of VT and distal bias flow. The higher the distal bias flow the more pronounced was the lowering effect on PaCO2. We conclude that during HFOV it is possible to improve CO2 elimination using small additional bias flow delivered near the tip of the endotracheal tube in animals with normal abnormal lung function. This may allow adequate alveolar ventilation with even smaller VT, thus reducing the risk of barotrauma.

Animals↗
PubMed1988

The role of leukotrienes in the late hemodynamic manifestations of group B streptococcal sepsis in piglets.

In order to evaluate the role of leukotrienes in group B streptococcal (GBS) sepsis we studied the effect of a leukotriene receptor antagonist, FPL 57231, on the late hemodynamic changes occurring secondary to an infusion of live GBS. Paralyzed, mechanically ventilated piglets received a continuous intravenous infusion of bacteria (5 x 10(7) org/kg/min) while systemic arterial (Psa) and pulmonary artery pressures (Ppa) were measured. To separate the effects of the lipoxygenase products of arachidonic acid from those of the cyclooxygenase by-products, animals in control and treatment groups received indomethacin, a cyclooxygenase blocking agent, 15 min after the infusion of GBS was begun. In addition to GBS and indomethacin, treatment animals received a 30 min infusion of FPL 57231 starting 120 min after the bacterial infusion was begun. All study animals responded to bacteria within 15 min with marked elevation in pulmonary artery pressure (X +/- SD) (12 +/- 3 to 49 +/- 5 mmHg; p less than .01), and a decline in PaO2 (84 +/- 9 to 49 +/- 5 mmHg; p less than .01) and cardiac output (0.29 +/- 0.04 to 0.18 +/- .07 liter/min/kg; p less than .01). These changes were reversed by indomethacin. Subsequent values remained relatively stable until approximately 90 min when a gradual decrease in cardiac output (CO) and PaO2, and an increase in Ppa, and calculated systemic (SVR) and pulmonary (PVR) vascular resistances occurred. After the initial increase in TxB2 and 6-keto-PGF1 alpha, indomethacin treatment resulted in return of these values to baseline with no further increase throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Prophylactic indomethacin for prevention of intraventricular hemorrhage in premature infants.

The impact of early prophylactic use of intravenous indomethacin on the incidence and severity of periventricular-intraventricular hemorrhage and patent ductus arteriosus in 199 oxygen-requiring premature infants (less than or equal to 1300 g birth weight) was prospectively investigated. The trial was controlled, the infants were randomized, and the investigators were unaware of the group assignments. Patients with minimal (grade I) or no periventricular-intraventricular hemorrhage determined by prestudy echoencephalography were randomized within two birth weight subgroups (500 to 899 and 900 to 1300 g) to receive either prophylactic indomethacin (n = 99) or an equal volume of saline-vehicle placebo (n = 100). The first dose (0.2 mg/kg) was given within 12 hours of delivery and two subsequent doses (0.1 mg/kg) were administered at 12 hourly intervals. Prophylactic indomethacin significantly reduced the incidence of grades II to IV periventricular-intraventricular hemorrhage. Intraventricular hemorrhage was half as common in infants given prophylactic indomethacin as in control infants (23% v 46%, P less than .002). The reduction was manifested in both birth weight subgroups. Results of this study also confirmed a lower incidence of clinically significant patent ductus arteriosus in infants who received prophylactic indomethacin in contrast to those who received placebo (11% v 42%, P less than .001). No significant differences were found between treatment and control groups in the duration of oxygen therapy, mechanical ventilation, or hospitalization or in the incidence of pneumothorax, chronic lung disease, sepsis, necrotizing enterocolitis, retinopathy of prematurity, or death. Early prophylactic indomethacin initiated within 12 hours of delivery is effective in reducing the incidence of intraventricular hemorrhage as well as clinically significant patent ductus arteriosus in very low birth weight premature infants.

Birth Weight↗
PubMed1987

Transcutaneous oxygen monitoring and retinopathy of prematurity.

This study was performed to determine whether the use of continuous tcPO2 monitoring could reduce the incidence of ROP in preterm infants receiving oxygen therapy. Two hundred and ninety-six infants with birth weights less than or equal to 1300 grams were randomly assigned to a continuous monitoring (CM) or a standard care (SC) group. CM infants had tcPO2 monitored continuously as long as they required supplemental oxygen while SC infants had tcPO2 monitored only during the more acute state of their illness. Management of both groups was otherwise identical. One hundred and one of 148 infants in the CM and 113 of 148 patients in the SC groups survived. Mean birth weights and gestational age were similar in both groups. Duration of mechanical ventilation and oxygen therapy was also similar. The overall incidence of ROP was 51% in the CM and 59% in the SC group. As birth weight for infants greater than or equal to 1000 grams increased a higher risk for developing ROP was noted in the SC group. Four infants in the CM and 5 in the SC group developed cicatricial ROP. These results suggest that continuous tcPO2 monitoring may reduce the incidence of ROP in infants with birth weights greater than 1000 grams, but not in the smaller infants in whom this complication occurs more frequently and is more severe.

Birth Weight↗
PubMed1987

Serial determination of pulmonary function in infants with chronic lung disease.

Pulmonary function was measured in 39 infants with chronic lung disease who had required mechanical ventilation starting during the first week of life for a median of 9 days (range 1 to 46 days) and supplemental oxygen for a median of 48 days (range 28-162 days). Their mean birth weight was 1140 g (range 550 to 2325 g), and mean gestational age 29.8 weeks (range 26 to 37 weeks). Ventilation was measured by pneumotachography, esophageal pressure through a water-filled feeding tube, and functional residual capacity (FRC) by a modified nitrogen washout technique. Lung compliance, pulmonary conductance, and FRC were determined at 1, 3, 6, 12, 18, 24, and 36 months after birth. Pulmonary function was also determined in 40 normal children, ranging in age from neonates to 5 years, who served as controls. In infants with chronic lung disease, growth in weight and length followed the 10th to 25th percentiles of the normal curve. Minute ventilation and respiratory effort remained elevated throughout the follow-up. FRC per kilogram of body weight was decreased at 1, 3, and 6 months after birth, but thereafter was in the normal range. FRC increased in proportion to weight at the same rate as in the controls. Lung compliance was only half of normal at 1 month, increased with growth in close correlation with weight, and was approximately 80% of normal at the end of follow-up. Pulmonary conductance was 50% of normal at 1 month, increased little during the first 6 months, but reached 85% of normal at 3 years of age. There was no evidence of gas trapping. These results indicate that in infants with chronic lung disease after mechanical ventilation, lung volume increases normally, probably by formation of new alveoli, which also leads to improvement in lung compliance. Airway growth is slow during the first 6 months after birth, but the subsequent faster growth leads to conductance values close to normal at 3 years of age.

Body Weight↗
PubMed1987

Gas trapping with high-frequency ventilation: jet versus oscillatory ventilation.

Gas trapping was evaluated during high-frequency jet ventilation (HFJV) and high-frequency oscillatory ventilation (HFOV) in nine adult rabbits under basal conditions and after instillation of a mixture of 20% human meconium (2 mL/kg). The anesthetized animals underwent tracheostomy and were placed inside a body plethysmograph. Respiratory compliance and resistance were calculated from airway pressure and simultaneous flow, and volume was measured with a pneumotachograph. Gas trapping was measured as the change in volume observed in the plethysmograph after clamping the jet or the oscillatory line at respiratory rates of 10 and 15 Hz and tidal volumes of 1.0 and 2.0 mL/kg. Mean airway pressure was similar with both ventilators. Inspiratory/expiratory ratios were 1:4 at 10 Hz and 1:2 at 15 Hz with HFJV, and 1:1 during HFOV. Under all conditions, gas trapping was significantly greater with HFJV than with HFOV. More gas trapping was observed with higher tidal volume (2 mL/kg) and respiratory rate (15 Hz) during HFJV, before and after meconium instillation. After meconium instillation, gas trapping during HFJV at 15 Hz and tidal volume 2 mL/kg decreased significantly (32.7 +/- 10.4 to 24.9 +/- 10.3; P less than 0.05), compared with basal conditions. This finding may be explained by the shorter time constant of the respiratory system after meconium instillation (0.118 vs 0.083 seconds, P less than 0.01). Thus gas trapping was significantly greater with HFJV than with HFOV, a difference most likely related to the active expiratory phase of HFOV.

Airway Obstruction↗
PubMed1987

Retinopathy of prematurity. A randomized, prospective trial of transcutaneous oxygen monitoring.

To determine whether the use of continuous transcutaneous oxygen monitoring (tcPO2) could reduce the incidence of retinopathy of prematurity (ROP) in pre-term infants receiving oxygen therapy, a randomized, prospective trial of constant monitoring using the transcutaneous oxygen monitor versus intermittent monitoring of oxygen was performed on a population of premature infants at very high risk for the development of ROP. Two hundred ninety-six infants were randomly assigned to either a constantly monitored (CM) or standard care (SC) group. CM infants had tcPO2 monitored continuously as long as they required supplemental oxygen, whereas SC infants had tcPO2 monitored only during the more acute state of their illness. Management of both groups was otherwise identical. One hundred one of 148 infants in the CM group and 113 of 148 in the SC group survived. The overall incidence of ROP was 51% in the CM group and 59% in the SC group (no significant difference). In infants over 1000 g birthweight, as the weight increased there was increasing risk of developing ROP in the SC group. The odds ratio for the ROPsc:ROPcm reached 7.6 in infants between 1200 and 1300 g in infants with Apgar scores greater than or equal to 8 at 5 minutes. The incidence of cicatricial ROP was similar in both groups: four in the CM and five in the SC group.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Extrathoracic airway stability during resistive loading in preterm infants.

Extrathoracic airway (ETA) stability was tested in 10 preterm infants during sleep with a drop in intraluminal pressure produced by the application of an external inspiratory flow-resistive load (IRL, 125 cmH2O.1-1.s at 1 l/min). An increase in total pulmonary resistance was sought as the measure of airway narrowing. The role of the ETA in the increased pulmonary resistance with loading was examined by testing the same infants while endotracheally intubated and after extubation. Total pulmonary resistance decreased with loading during the intubated studies (102.5 +/- 41.2 to 82.4 +/- 33.3 cmH2O.1-1.s, P less than 0.05), whereas a significant increase in pulmonary resistance was seen with loading in the extubated studies (101 +/- 58.1 to 128 +/- 68.6 cmH2O.1-1.s, P less than 0.01). Intraluminal pressure in the ETA, measured by the lowest proximal airway pressure, fell significantly with loading in both conditions, with values changing from -0.7 +/- 0.3 to -4.7 +/- 2.7 cmH2O in the intubated infants and from -0.9 +/- 0.3 to -4.6 +/- 0.9 cmH2O) in the extubated infants (P less than 0.01). The results suggest ETA narrowing with loading in extubated infants despite the absence of overt obstructive apnea. Measurements of total pulmonary resistance with IRL can be used as a simple test of ETA stability.

Airway Obstruction↗
PubMed1987

Hemodynamic and ventilatory effects of high-frequency jet and conventional ventilation in piglets with lung lavage.

The cardiovascular and ventilatory effects of high-frequency jet ventilation (HFJV) and conventional ventilation (CV) were evaluated in a saline lung lavage model in piglets. After saline lavage and stabilization on CV, animals were randomized to either mode of ventilation for 4 h. Arterial blood gases, cardiac output, mean pulmonary and arterial blood pressures, and pulmonary and systemic vascular resistances were compared between groups. Alveolar-arterial oxygen gradient (AaDO2) was lower in the HFJV than in the CV group after 3 h of ventilation (p less than 0.04). The peak inspiratory pressure necessary to maintain PaCO2 within the normal range was approximately half as much in the HFJV group as in the CV group (p less than 0.005) throughout the entire study period. Mean airway pressure, cardiac output, mean pulmonary and arterial blood pressures as well as pulmonary and systemic vascular resistances were not statistically different between groups. These results suggest that in this model, HFJV produces better oxygenation with lower peak airway pressures compared to CV without producing hemodynamic compromise.

Airway Resistance↗