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Biomedical subjects

A Piotrowski

Publications and source records attributed to A Piotrowski.

At least 19 recordsLinked to original sources
PubMed2001

Lack of role for nitric oxide in cholinergic modulation of myocardial contractility in vivo.

Despite intensive investigation, the role of nitric oxide (NO) in cholinergic modulation of myocardial contractility remains unresolved. The left anterior descending coronary artery of 34 anesthetized, open-chest dogs was perfused via an extracorporeal circuit. Segmental shortening (SS) was measured with ultrasonic crystals and coronary blood flow (CBF) was measured with an ultrasonic flow transducer. An intracoronary infusion of ACh (20 microg/min) was performed, with CBF held constant, under baseline and during dobutamine, CaCl(2), or amrinone at doses increasing SS by approximately 50% (10 microg/min, 15 mg/min, and 300 microg/min ic, respectively). ACh-induced responses during dobutamine were also assessed following treatment with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microg/min ic for 15 min). The effects of sodium nitroprusside (SNP; 80 microg/min ic), an exogenous NO donor, bradykinin (2.5 microg/min ic), a nonmuscarinic releaser of endothelial NO, and bilateral vagal stimulation (before and after L-NAME) were evaluated during dobutamine. ACh had no effect on SS under baseline or during CaCl(2), but it decreased SS during dobutamine or amrinone (-23 +/- 4% and -30 +/- 5%, respectively). Vagal stimulation also reduced SS during dobutamine. L-NAME did not alter the ACh- or vagal-induced decreases in SS during dobutamine. Neither SNP nor bradykinin affected SS during dobutamine. In conclusion, ACh and vagal stimulation have a negative inotropic effect during stimulation of the beta-adrenergic receptors that is independent of NO. The persistence of this effect during amrinone suggests that a mechanism downstream from adenylate cyclase is involved.

Acetylcholine↗
PubMed2000

Predominant staphylococci in the intensive care unit of a paediatric hospital.

Coagulase-negative staphylococci cause a significant number of infections, especially in immunocompromised patients, including premature neonates. Nosocomial strains present in the environment create a special risk.We studied staphylococci isolated from the intensive care unit of a paediatric teaching hospital over the period of six months in 1997. Biotyping and species identification were performed; resistance to methicillin and other beta-lactam antibiotics and patterns of resistance to antimicrobial agents were determined. Staphylococcus cohnii was the predominant species of 147 isolates of staphylococci recovered from the ward environment. Strains were resistant to several antibiotics and 97% were resistant to methicillin. In isolates from infants (72) methicillin-resistant strains of Staphylococcus epidermidis were predominant. Susceptibility to beta-lactams (penicillin, amoxycillin, amoxycillin-clavulanic acid and cephalosporins: cephalothin, cefuroxime and cefotaxime) showed differences between the two species. Some S. cohnii were susceptible to penicillin and amoxycillin despite methicillin-resistance. S. epidermidis were relatively susceptible to amoxycillin-clavulanic acid and cephalosporins. All strains investigated were susceptible to vancomycin, but nearly 30% demonstrated high-level resistance to mupirocin. The search for strains of the same origin showed clones belonging to S. epidermidis, S. hominis and S. saprophyticus but not S. cohnii.A large number of multiresistant, phenotypically different S. cohnii strains surviving in the ward environment may provide a reservoir of antimicrobial resistance genes.

Bacterial Typing Techniques↗
PubMed2000

Direct coronary vasomotor effects of sevoflurane and desflurane in in situ canine hearts.

BACKGROUND: An extracorporeal system was used to investigate the direct coronary vasomotor effects of sevoflurane and desflurane in vivo. The role of the adenosine triphosphate-sensitive potassium channels (KATP channels) in these effects was evaluated. METHODS: Twenty-one open-chest, anesthetized (fentanyl-midazolam) dogs were studied. The left anterior descending coronary artery was perfused at controlled pressure (80 mmHg) with normal arterial blood or arterial blood equilibrated with either sevoflurane or desflurane. Series 1 (n = 16) was divided into two groups of equal size on the basis of whether sevoflurane (1.2, 2.4, and 4.8%) or desflurane (3.6, 7.2, and 14.4%) was studied. The concentrations for the anesthetics corresponded to 0.5, 1.0, and 2.0 minimum alveolar concentration (MAC), respectively. Coronary blood flow (CBF) was measured with an ultrasonic, transit-time transducer. Local coronary venous samples were obtained and used to evaluate changes in myocardial oxygen extraction (EO2). In series 2 (n = 5), changes in CBF by 1 MAC sevoflurane and desflurane were assessed before and during intracoronary infusion of the KATP channel inhibitor glibenclamide (100 microg/min). RESULTS: Intracoronary sevoflurane and desflurane caused concentration-dependent increases in CBF (and decreases in EO2) that were comparable. Glibenclamide blunted significantly the anesthetic-induced increases in CBF. CONCLUSIONS: Sevoflurane and desflurane have comparable coronary vasodilative effects in in situ canine hearts. The KATP channels play a prominent role in these effects. When compared with data obtained previously in the same model, the coronary vasodilative effects of sevoflurane and desflurane are similar to those of enflurane and halothane but considerably smaller than that of isoflurane.

ATP-Binding Cassette Transporters↗
PubMed1997

Patient-initiated, pressure-regulated, volume-controlled ventilation compared with intermittent mandatory ventilation in neonates: a prospective, randomised study.

OBJECTIVE: To compare the effects of patient-initiated, pressure-regulated, volume-controlled ventilation (PRVC) with pressure-preset intermittent mandatory ventilation (IMV) in neonates with respiratory failure. DESIGN: Randomised, prospective study. SETTING: Intensive care unit (14 beds) in a 300-bed paediatric teaching hospital. PATIENTS: 60 neonates with respiratory distress syndrome (RDS) or congenital pneumonia, weighing < 2500 g and requiring mechanical ventilation. INTERVENTIONS: Ventilatory support until extubation via either IMV (n = 30) or PRVC (n = 27). In PRVC, the tidal volume (VT) was preset and pressure-controlled breaths delivered with peak inspiratory pressure values adapted to achieve the preset VT. MEASUREMENTS AND RESULTS: Main outcome measures were duration of ventilation and incidence of bronchopulmonary dysplasia (BPD). Pulmonary air leaks and intraventricular haemorrhage (IVH) were considered major adverse effects. Demographic data, ventilation parameters and arterial/alveolar oxygen tension ratio were similar at randomisation. Duration of ventilation and incidence of BPD were not decreased by the use of PRVC. Air leaks occurred in 3 neonates in the PRVC group and in 7 babies treated with IMV (NS). The incidence of IVH grade > II was lower in babies treated with PRVC (p < 0.05). In a subgroup of neonates weighing < 1000 g, the duration of ventilation and incidence of hypotension were reduced in the PRVC group (p < 0.05). CONCLUSION: Patient-initiated, pressure-regulated, volume-controlled ventilation can be safely used in neonates and may contribute to a lower incidence of complications.

Female↗
PubMed1996

Circulatory and diuretic effects of dopexamine infusion in low-birth-weight infants with respiratory failure.

OBJECTIVE: To investigate the effects of infusion of dopexamine hydrochloride, a new synthetic catecholamine, on cardiopulmonary status and urine output in neonates with respiratory and circulatory failure. DESIGN: Prospective clinical study with each patient serving as his own control. SETTING: Intensive care unit (14 beds) in a 300-bed paediatric teaching hospital. PATIENTS: Seventeen neonates with low birth weight (LBW) requiring mechanical ventilation in the first 4 days of life, who initially had two of the following symptoms: hypotension, oliguria, metabolic acidosis with base deficit >10 and failure to respond to volume loading. INTERVENTIONS: Cardiopulmonary variables, diuresis and acid-base status were measured before and after volume loading, in patients who did not improve infusion of dopexamine was started at a dose of 2 microg kg-1 min-1 which was titrated to achieve blood pressure, urine output, and base deficit in normal range. Observations were continued for a period of 5 h. MEASUREMENTS AND RESULTS: Systolic blood pressure increased significantly after 3 h. of dopexamine infusion and remained elevated up to the end of the study period. Diastolic and mean blood pressure increased slightly (NS). Diuresis increased significantly from the 4th h of dopexamine infusion. Arterial blood pH increased significantly from baseline at 5 h after the start of dopexamine administration. There was also a significant improvement in the PtcO2/PaO2 index. CONCLUSION: In neonates with respiratory and circulatory failure, dopexamine increases blood pressure and improves arterial pH and urine output.

Acidosis, Respiratory↗
PubMed1995

Cannulation of the axillary artery in critically ill newborn infants.

UNLABELLED: The axillary artery has been successfully cannulated in critically ill adult and paediatric patients. There is little information about experience with this technique in neonates. We report the use of axillary cannulation in 62 mechanically ventilated neonates with birth weight from 750 to 3800 g (mean 1950 g). The axillary artery was catheterized with 24 or 22 gauge teflon catheters by means of the catheter-over-a-needle technique. Arterial access was used for blood pressure monitoring, blood sampling and in seven cases for blood removal during exchange transfusions. Cannulae were removed when the fraction of inspired oxygen (FIO2) was less than 0.3. During cannulation capillary refill, radial artery pulse and neurological status of the arm were checked daily. The mean period of cannulation was 4.1 days (1-10 days). During cannulation and after catheter removal there were no complications related to the chosen vessel e.g. no change in the skin colour, skin warmth, capillary refill and the quality of the radial pulse. No changes in the motor activity of the limb on the cannulated side were observed. CONCLUSION: Axillary artery cannulation is a useful alternative for establishing an arterial access in ventilated neonates. Further studies are needed to evaluate the long-term consequences of this technique.

Axillary Artery↗
PubMed1993

Comparison of atracurium and pancuronium in mechanically ventilated neonates.

OBJECTIVE: To compare haemodynamic and gas exchange effects after either atracurium or pancuronium given to ventilated neonates with respiratory failure. DESIGN: In this prospective study neonates were alternately assigned to receive either atracurium or pancuronium, intravenously. SETTING: Paediatric and neonatal ICU in a teaching hospital. PATIENTS: 21 ventilated neonates with mean birth weight of 2293 g, suffering from respiratory distress syndrome, meconium aspiration syndrome or pneumonia were included in the study. Patients were entered if they were breathing out of phase with the ventilator and required FIO2 > 0.4 and peak inspiratory pressure (PIP) > 15 cm H2O. Exclusion criteria were unstable haemodynamics or a pneumothorax. INTERVENTIONS: Heart rate, respiratory rate, invasive blood pressure and transcutaneous oxygen tension were monitored continuously. IV atracurium (0.3 mg/kg) or pancuronium (0.1 mg/kg) were administered. Arterial blood gas analysis was performed before and 10 min after injection of muscle relaxant. MEASUREMENTS AND RESULTS: Atracurium caused a significant decrease in heart rate (p < 0.05), systolic and mean blood pressure (p < 0.01). There was also a slight decrease in PaO2 and PaCO2 (n.s.). Administration of pancuronium resulted in an increase in heart rate (p < 0.01) and a slight decrease of blood pressure (n.s.). PaCO2 remained unchanged, whereas PaO2 increased slightly (n.s.). The PtcO2 index (PtcO2/PaO2) decreased after atracurium and did not change after pancuronium (both n.s.). With both drugs a slight increase in alveolar to arterial oxygen tension difference was observed (n.s.). There was one episode of hypotension and one of hypoxaemia--both after pancuronium. CONCLUSION: Both drugs may be used for muscle relaxation in neonates with respiratory failure. Atracurium however causes more cardiovascular depression, whereas the effect of pancuronium may be difficult to predict.

Atracurium↗
PubMed1993

[Bacterial flora of the hospital environment: identification, susceptibility to disinfecting agents, antibiotics and chemotherapeutics].

The studies were performed at the Intensive Care Unit of the Institute of Pediatrics. There were aimed at determination of cleanliness of boxes together with ante-rooms. At the same time bacterial flora of hospitalized children was investigated. The bacteria were isolated and identified by classical methods and by the API system. Among the identified strains, 60% constituted Gram-positive cocci with dominant participation of coagulase-negative staphylococci. Gram-negative rods (25% of total bacterial number) were represented mainly by Pseudomonas and Acinetobacter. Determination of susceptibility of tested strains toward 24 antibiotics and chemotherapeutics demonstrated wide occurrence of multiple antibiotic-resistance, particularly among enterococci and Gram-negative rods. Tests for susceptibility to disinfectants revealed presence of strains sensitive to chloramine in concentrations a dozen times higher when compared with standard strains. These strains occurred in the ward after systematic use of this disinfectant for many years. After replacement of chloramine by sterinol and chlorhexidine, these bacteria were not detectable after one year.

Acinetobacter↗