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Biomedical subjects

J Pfenninger

Publications and source records attributed to J Pfenninger.

At least 37 records · Page 2Linked to original sources
PubMed1993

Respiratory response to salbutamol (albuterol) in ventilator-dependent infants with chronic lung disease: pressurized aerosol delivery versus intravenous injection.

OBJECTIVE: To compare the effects of intravenously injected with inhaled salbutamol in ventilator dependent infants with chronic lung disease (CLD). DESIGN: Prospective randomized study which each patient served as his/her own control. SETTING: Multidisciplinary neonatal and pediatric ICU. PATIENTS: 8 ventilator dependent premature infants with CLD. INTERVENTIONS: Salbutamol, 10 micrograms/kg was given intravenously, and 10-19 h later, twice 100 micrograms as pressurized aerosol, or vice versa, sequence randomized. The pressurized aerosol was delivered by a metered dose inhaler into a newly developed aerosol holding chamber, integrated into the inspiratory limb of the patient circuit. Respiratory system mechanics were assessed by the single breath occlusion method before and 10 and 60 min after drug administration. MEASUREMENTS AND RESULTS: Compliance improved significantly after intravenous injection (0.48 +/- 0.18 to 0.67 +/- 0.16, p < 0.01 and 0.59 +/- 0.23 ml/cmH2O/kg, NS, (mean +/- 1 SD) and after inhalation (0.46 +/- 0.19 to 0.64 +/- 0.32, p < 0.01 and 0.56 +/- 0.31 ml/cmH2O/kg, NS). Resistance decreased after iv. use (0.38 +/- 0.17 to 0.25 +/- 0.11, p < 0.001 and 0.25 +/- 0.10 cmH2O/ml/s, NS) and after inhalation (0.35 +/- 0.12 to 0.27 +/- 0.09, p < 0.01 and 0.28 +/- 0.12 cmH2O/ml/s, NS). Heart rate increased significantly after both routes of application, whereas mean arterial pressure, respirator settings, FIO2, transcutaneous SO2 and capillary PCO2 did not change. CONCLUSIONS: Inhaled and intravenous salbutamol improves pulmonary mechanics to the same extent with comparable side effects, and may therefore be used to facilitate weaning from respirators.

Administration, Inhalation↗
PubMed1992

Lung mechanics and gas exchange in ventilated preterm infants during treatment of hyaline membrane disease with multiple doses of artificial surfactant (Exosurf)

Eight premature infants ventilated for hyaline membrane disease and enrolled in the OSIRIS surfactant trial were studied. Lung mechanics, gas exchange [PaCO2, arterial/alveolar PO2 ratio (a/A ratio)], and ventilator settings were determined 20 minutes before and 20 minutes after the end of Exosurf instillation, and subsequently at 12-24 hour intervals. Respiratory system compliance (Crs) and resistance (Rrs) were measured by means of the single breath occlusion method. After surfactant instillation there were no significant immediate changes in PaCO2 (36 vs. 37 mmHg), a/A ratio (0.23 vs. 0.20), Crs (0.32 vs. 0.31 mL/cm H2O/kg), and Rrs (0.11 vs. 0.16 cmH2O/mL/s) (pooled data of 18 measurement pairs). During the clinical course, mean a/A ratio improved significantly each time from 0.17 (time 0) to 0.29 (time 12-13 hours), to 0.39 (time 24-36 hours) and to 0.60 (time 48-61 hours), although mean airway pressure was reduced substantially. Mean Crs increased significantly from 0.28 mL/cmH2O/kg (time 0) to 0.38 (time 12-13 hours), to 0.37 (time 24-38 hours), and to 0.52 (time 48-61 hours), whereas mean Rrs increased from 0.10 cm H2O/mL/s (time 0) to 0.11 (time 12-13 hours), to 0.13 (time 24-36 hours) and to (time 48-61 hours) with no overall significance. A highly significant correlation was found between Crs and a/A ratio (r = 0.698, P less than 0.001). We conclude that Exosurf does not induce immediate changes in oxygenation as does the instillation of (modified) natural surfactant preparations. However, after 12 and 24 hours of treatment oxygenation and Crs improve significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Dioxide↗
PubMed1991

[Incidence and prognostic significance of positive blood cultures in neonatal and pediatric intensive care].

The incidence and prognostic importance of positive blood cultures were evaluated over a two-year period (1986/87) in 1371 admissions to a multi-disciplinary neonatal and pediatric intensive care unit (ICU). Blood cultures were performed in 439 patients of which 80 cultures were positive. Septicemia was confirmed in 70 cases, the 10 remaining cases being classified as contamination or bacteremia. The incidence of nosocomial, ICU-acquired septicemia was low (7/70). The major causative organisms of sepsis were those commonly encountered in neonatal and pediatric infections, including Haemophilus influenzae (37), Escherichia coli (11, Neisseria meningitidis (9) and group B streptococci (3). Typically nosocomial organisms were rare. In the group of 70 septicemic cases, multiple organ system failure was diagnosed in 23 patients. Nine died, most often due to irreversible septic shock (13% mortality). In order to avoid a selection bias, all admissions were examined for the presence of sepsis syndrome (clinical signs of sepsis with negative blood cultures). Out of 21 such patients, three died. The results suggest that in comparison to intensive care in adults the following conclusions may be drawn: (1) sepsis with positive blood cultures plays a minor role at our unit; (2) the rate of ICU-acquired septicemia is low (10% of all cases of sepsis with positive blood culture); and (3) the prognostic bearing of a positive blood culture in patients with septic signs is not too unfavourable (87% survival rate).

Bacterial Infections↗
PubMed1991

The paradox of adult respiratory distress syndrome in neonates.

Six full-term newborn infants are described who suffered from severe adult respiratory distress syndrome (ARDS). The triggering event was intrauterine/perinatal asphyxia in five, and group B streptococcal (GBS) septicemia in three. All had severe respiratory distress/failure and were ventilated mechanically with high concentrations of inspired oxygen and positive end-expiratory pressure. Radiography of the chest showed dense bilateral consolidation with air bronchograms and reduced lung volume. Persistent pulmonary hypertension (PPH) was documented in all cases. The coincidence of ARDS and PPH rendered respiratory management extremely difficult. For this reason high-frequency ventilation was instituted in all patients in order to improve CO2 elimination and induce respiratory alkalosis. Acute complications of respiratory therapy were encountered in five patients (pneumothorax, pulmonary interstitial emphysema, pneumopericardium). Three infants died (irreversible septic shock, progressive severe hypoxemia, and sudden cardiac arrest) after 17, 80, and 175 h of life. Histologic examination of the lungs was possible in all fatal cases and revealed typical changes of acute to subacute stages of ARDS. Three infants survived, the mean time of mechanical respiratory support being 703 h. Two patients were still dependent on oxygen after 1 month of life, and all survivors had increased interstitial markings and increased lung volumes on their chest roentgenograms at this time.

Asphyxia Neonatorum↗
PubMed1991

Atrial natriuretic factor after cardiac surgery with cardiopulmonary bypass in children.

OBJECTIVE: To determine circulating atrial natriuretic factor (ANF) concentrations in the postoperative state and to define potential hemodynamic determinants of regional plasma ANF concentrations. DESIGN: Cohort study. SETTING: Pediatric ICU in a university hospital. PATIENTS: Twenty-two children, mean age 4.2 yrs (range 0.9 to 13.5), were studied 18 hrs after corrective surgery on cardiopulmonary bypass. The underlying cardiac malformations were ventricular septum defect (n = 5), transposition of great arteries (n = 5), tetralogy of Fallot (n = 4), pulmonary stenosis (n = 3), and miscellaneous (n = 5). INTERVENTIONS: In addition to the commonly monitored variables in postoperative cardiac patients, blood volume was estimated by the 125I albumin method, and plasma samples for radioimmunoassay determination of ANF concentrations were taken simultaneously from indwelling catheters. MEASUREMENTS AND MAIN RESULTS: Compared with normal age-matched values, plasma ANF concentrations were increased in all patients, with values tending to be highest in the left atrium, followed by systemic artery, superior vena cava, and pulmonary artery (345 +/- 158, 333 +/- 169, 311 +/- 154, and 272 +/- 160 pg/mL, respectively [mean +/- SD; NS]). Simple regression analysis demonstrated a moderate correlation between blood volume and the concentration of ANF in the superior vena cava (p less than .05). Stepwise multivariate analysis showed no significant independent predictor of plasma ANF concentrations. CONCLUSIONS: Plasma ANF concentrations are increased after open-heart surgery in children, with moderate direct correlation to blood volume. The wide scatter of increased hormone concentrations may be explained by the many factors known to influence circulating ANF concentrations, such as age, underlying disease, cardiovascular state, and drugs.

Adolescent↗
PubMed1990

A comparison of ceftriaxone and cefuroxime for the treatment of bacterial meningitis in children.

To compare ceftriaxone with cefuroxime for the treatment of meningitis, we conducted a study in which 106 children with acute bacterial meningitis were randomly assigned to receive either ceftriaxone (100 mg per kilogram of body weight per day, administered intravenously once daily; n = 53) or cefuroxime (240 mg per kilogram per day, administered intravenously in four equal doses; n = 53). The mean age of the children was 3 years (range, 42 days to 16 years), and the characteristics of the two treatment groups were comparable at admission. Excluded from the study were eight other children who died within 48 hours of admission. After 18 to 36 hours of therapy, cultures of cerebrospinal fluid remained positive for 1 of the 52 children (2 percent) receiving ceftriaxone for whom cultures were available and 6 of 52 (12 percent) receiving cefuroxime (P = 0.11). In both groups the mean duration of antibiotic therapy was 10 days. The clinical responses to therapy were similar in the two treatment groups, and all 106 children were cured. Reversible biliary pseudolithiasis was detected by serial abdominal ultrasonography only in the children treated with ceftriaxone (16 of 35 vs. 0 of 35; P less than 0.001). The treatment of three children was switched from ceftriaxone to alternative antibiotics because these children had upper abdominal pain. Other side effects were infrequent in both groups. At follow-up examination two months later, moderate-to-profound hearing loss was present in two children (4 percent) treated with ceftriaxone and in nine (17 percent) treated with cefuroxime (P = 0.05); other neurologic abnormalities were similar in the two treatment groups. We conclude that ceftriaxone is superior to cefuroxime for the treatment of acute bacterial meningitis in children and that the benefits of milder hearing impairment and more rapid sterilization of the cerebrospinal fluid with ceftriaxone outweigh the problem of reversible biliary pseudolithiasis with this drug.

Adolescent↗
PubMed1989

Pulmonary problems following multiple trauma in children.

Acute respiratory failure (ARF = hypoxemia and/or hypercapnia) is a frequent finding in the polytraumatized patient. Multiple injury is often accompanied by injury of the central nervous system, and the presence or absence of ARF may play a key role for survival and late morbidity. This paper reviews the incidence of pulmonary problems after severe head injury and the possible dysfunctions of the respiratory apparatus following single or multiple trauma. Diagnostic work-up in ARF includes consideration of the mechanisms of injury, clinical examination, determinations of arterial blood gases and chest radiographs which are all essential for the choice of an effective treatment. This frequently includes supportive treatment by continuous positive pressure ventilation.

Child↗
PubMed1988

Pressure-volume curves, static compliances and gas exchange in hyaline membrane disease during conventional mechanical and high-frequency ventilation.

Eight premature infants with hyaline membrane disease needing artificial ventilation were studied at a mean age of 26.5 h. After a preparative phase they were randomly assigned either first to conventional mechanical ventilation (CMV; delivered by a Siemens Servo 900 C), followed by high-frequency ventilation (HFV; delivered by Percussionaire VDR 1 at 10 Hz) or vice versa, each period lasting 4 h. At the end of each period, arterial blood gases, lung volumes and alveolar pressures (Palv) during CMV or HFV and pressure-volume (P-V) curves of the total respiratory system were determined. Expiratory volumes were measured spirometrically, Palv by the clamping method, and the P-V curve was constructed by the syringe method. Single point static compliance at end-inspiration was higher during HFV (0.40 +/- 0.10 vs. 0.32 +/- 0.08 ml/cmH2O.kg-1; p = 0.02), whereas at end-expiration no difference was noted. Two points static compliances were also better during HFV than during CMV (0.32 +/- 0.08 vs. 0.24 +/- 0.06 ml/cmH2O.kg-1; p = 0.01). Static compliances derived from the steepest part of the inflation limb of the P-V curve were 0.55 +/- 0.12 after CMV and 0.50 +/- 0.12 ml/cmH2O.kg-1 after HFV (n.s.). Compared to CMV, HFV resulted in similar oxygenation and CO2-elimination at equal mean lung volumes, but at significantly lower mean Palv. It is concluded that recruitment of lung volume is achieved with less static recoil pressure by HFV. These findings are explained by differences in inspiration allowing more time for volume recruitment during HFV.

Clinical Trials as Topic↗
PubMed1987

Comparison between transcutaneous PO2 and pulse oximetry for monitoring O2-treatment in newborns.

213 paired tcpO2/paO2-data and 186 paired tcSO2/SaO2-data measured in 25 newborns (10 term, 15 prematures) were compared. The correlation coefficient for tcpO2/paO2 was 0.796, for tcSO2/SaO2 0.944. Sensitivity for discriminating between normo- and hypoxemia (paO2 less than 50 torr) was 82% for the tcpO2- and 88% for the tcSO2-method. Positive predictive values for discriminating between normo- and hypoxemia were 88% for both methods. Sensitivity for discrimination between normo- and hyperoxemia (paO2 greater than 100 torr) was 85% for the tcpO2- and 100% for the tcSO2-method. Positive predictive values for the discrimination between normo- and hyperoxemia were 58% and 25% for tcpO2- and tcSO2 respectively. Pulse oximetry proved to be less cumbersome than the tcpO2-method. However, as tcpO2, it could not be used in some very immature newborns and in those with circulatory instability. In conclusion, these preliminary results show a similar discrimination between normoxemia and hypo-hyperoxemia for both methods. A better sensitivity of pulse oximetry for hyperoxemia is counteracted by a lesser positive predictive value.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

High-frequency ventilation (HFV) in hyaline membrane disease--a preliminary report.

Eight premature babies affected by hyaline membrane disease and needing mechanical respiratory support were ventilated by means of a VDR 1 (Bird Space Technology) respirator at 10 Hz during a mean time of 51 h. Before HFV 7 infants had been on conventional mechanical ventilation (CMV) and one on nasal CPAP. The values of mean airway pressure (MAP) and oxygenation index (PaO2/FIO2) on CMV and HFV were (mean and range): CMV: MAP 15 (4-29) mm Hg, ox. index 15.47 (5.07-23.19) kPa; HFV after 1 h: MAP 15 (10-19) mm Hg, ox. index 24.13 (9.07-46.12) kPa. Improved oxygenation allowed rapid reduction of FIO2 in the following hours. Only 3 infants were weaned directly from VDR 1, 5 were switched back to CMV mainly because of technical failures of the respirator. The change from HFV to CMV was associated with a fall of PaO2/FIO2 from 35.99 (15.86-74.52) to 22.39 (7.33-31.46) kPa. The mean time of artificial ventilation (CMV + HFV) was 121 h (range 46-166). Except for 1 pneumothorax no medical complications were seen during HFV, and all patients survived. Despite impressive improvements in oxygenation it is cautioned against the use of the VDR 1 because of the high incidence of technical problems.

Airway Resistance↗
PubMed1987

The postnatal development and growth of the human lung. I. Morphometry.

The lungs of 7 children (age: 26 days to 5 years 4 months) who died from non-respiratory causes were morphometrically investigated by means of light and electron microscopy. For analysis, the set of data was supplemented with results obtained previously on 8 normal adult lungs using similar quantitative techniques (Gehr et al., 1978). The results allowed us to distinguish two phases of postnatal lung development and growth, the first phase lasting from birth to about 18 months and the second phase from then to adulthood. The first phase was characterized by an overproportionate volume increase in the O2-transporting media, air and blood, at the expense of the parenchymal tissue compartment. In the second phase, the volumetric composition of the lung did not change further because there was proportionate growth of all lung compartments. The growth curves for the airspace and capillary surface areas were not biphasic: they increased in direct proportion to lung volume from birth to adulthood, indicating a steady increase in the air-blood interface complexity during the entire growth period. As a consequence of the differences in growth paces between the various structural lung components in early childhood, the morphometric parameters showed large variations in their overall growth rates between birth and adulthood. Thus, the parenchymal tissue components increased by a factor of 15, lung volume and the gas-exchange surface areas between 20 and 25 times (in parallel to body mass), and, finally, the O2-transporting media, air and blood, more than 30 times. The morphometrically determined pulmonary diffusing capacity for O2 (DLO2) scaled with body mass to the power of 1.15, a value significantly different from 1. This relative improvement with age of the gas exchange function per unit body mass is due mainly to an overproportionate growth of the capillary blood compartment.

Adult↗
PubMed1987

Sequential intravenous-oral amoxycillin/clavulanate (Augmentin) therapy in paediatric hospital practice.

The efficacy and safety of intravenous and sequential intravenous-oral clavulanate-potentiated amoxycillin therapy was evaluated in 71 hospitalized paediatric patients, one month to 16 years of age. The infections treated included peritonsillar abscess (2 patients), purulent tracheitis (1), acute epiglottitis (24), pneumonia (31), pansinusitis (4), mastoiditis (1), cellulitis (4), lymphadenitis (2) and pyelonephritis (2). The severity of disease was rated as moderate in 31 patients (44%), and as severe in 40 (56%). Bacterial pathogens could be cultured in 26 cases (37%). The response to therapy was prompt and followed by clinical cure in each patient. Adverse drug effects included phlebitis (in 6%), mild gastrointestinal complaints (6%), rash (4%) and transient neutropenia and elevation of transaminases (one case each). It is concluded that amoxycillin/clavulanate is effective and safe treatment for bacterial infections of the respiratory tract, urinary tract, skin or soft tissues in children.

Administration, Oral↗
PubMed1986

Acute epiglottitis: management by short duration of intubation and hospitalisation.

One hundred and thirty-seven patients with acute epiglottitis were studied retrospectively with regard to the efficacy and safety of short duration of intubation and hospitalisation. All patients were treated by nasotracheal intubation and antibiotic therapy. Inhalation anesthesia with halothane/oxygen was the preferred method for intubation (80.3%). Extubation was based on clinical improvement in 88.1% and on laryngoscopy in 11.9% of cases. Fifty-four percent of the patients were extubated successfully within 24 h and 94.8% within 48 h. Three patients (2.2%) had to be reintubated once. The mean duration of intubation was 27.6 h (range 8-86) and of hospitalisation 4.0 days (range 2-9). Two children (1.5%) died because of severe hypoxic brain damage due to cardiorespiratory arrest prior to hospital admission. A follow-up study conducted via the family physician revealed only two major complications (granulation polyp of the vocal cords, 1; long-lasting hoarseness, 1). It is concluded that short duration of intubation and hospitalisation are effective and safe in the management of acute epiglottitis.

Anti-Bacterial Agents↗