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The purpose of this analysis was to investigate biochemical disturbances at presentation and initial fluid resuscitation before surgery in infantile pyloric stenosis. The charts of 139 consecutive infants (113 boys and 26 girls) between 7 d and 20 wk of age with hypertrophic pyloric stenosis were reviewed. The infants were treated at the Department of Pediatric Surgery, University of Bern, Switzerland, in the period between 1987 and 1997. A trend towards hypokalaemia (13 of the 139 patients), hypochloraemia (39 patients) and especially metabolic alkalosis (98 patients) was frequently noted on admission. In 84 patients, data on fluid management and on circulating sodium, potassium, chloride and the acid-base balance immediately before surgery were also available. In these patients a significant correlation was found between the parenteral chloride dose given for fluid repair (y = 0.310 x; r[sup s] = 0.54; p < 0.001) and the changes in plasma bicarbonate. The equation indicates that a chloride dose of 10 mmol/kg body weight is required to reduce plasma bicarbonate on average by 3 mmol/l. Conclusion: Since assessment of the fluid volume stated by physical examination and history is inaccurate in infants with vomiting, the severity of metabolic alkalosis helps to define the amount of fluid required for repair. [ABSTRACT FROM AUTHOR]

Background: The purpose of ureterocystoneostomy to correct vesicoureteral reflux is to thereby prevent recurrent febrile urinary tract infections (UTIs). The objective of this study was to determine the frequency of UTI in adult women who underwent reimplantation as children, with the emphasis on infections during pregnancy., Patients and Methods: Included in the study were women over 20 years of age who underwent surgery for primary reflux between 1969 and 2004. A total of 392 patients were identified and information on their case history, surgery and follow-up was collected from the medical records. A questionnaire, requesting information on their present state of health, and occurrences of lower or upper UTI since the age of 16 and during any pregnancies, was sent to 337 of these patients., Results: In all, 242 (84%) of the questionnaires were returned. UTIs had occurred in 42% of the women before they had any sexual activity; thereafter the frequency increased to 61%. In 113 of the 282 women, 242 pregnancies were recorded. UTI occurred during 59 pregnancies (24%): 19% lower, 5% upper. Risk factors for UTI during pregnancy were infections as adults or decreased differential renal function (< or = 30%)., Conclusions: There is an ongoing risk of UTI in adult women after anti-reflux surgery in childhood. During pregnancy, these women represent a population at risk who should be observed very closely.

Day-case surgery involves a considerable amount of stress not only for the children who undergo surgery but also for their parents. In a prospective survey analysis performed in 1995/1996, we identified the following main factors influencing the amount of stress experienced by parents: feelings of insufficient preparation and problems with postoperative pain at home. As a consequence, measures were taken regarding information and pain management, including the creation of an interactive CD-ROM. We then analysed the consequences of our interventions regarding parental stress. In this study we collected the data of all patients who underwent day-case surgery during two additional 13-month periods in 1997/1998 and 1999/2000. The methods of data collection remained unchanged for all three periods and included a questionnaire for the parents. In total, 1,490 questionnaires were analysed. Comparing the three time periods, parents' feelings of being well-informed improved significantly (91% vs. 98% vs. 97%, P < 0.0001). However, the percentage of those experiencing moderate to severe stress did not change substantially (16% vs. 9% vs. 19%, not significant). Analgaesics were given more frequently over the years in a general as well as a prophylactic manner (20% vs. 35% vs. 43%, P < 0.0001). Nevertheless, problems with pain control at home remained unchanged (33% vs. 23% vs. 29%, not significant). Despite considerable efforts to improve information, parental stress did not significantly decrease. It cannot be assessed yet whether wrong information was given or whether a certain degree of stress cannot be prevented. There is some evidence that improvements in coping with pain-related problems might be a promising next step.

The aim of the study was to analyse the outcomes of children born with oesophageal atresia over the last 3 decades. The records of 104 patients born between 1973 and 1999 were reviewed retrospectively. To evaluate changes over time, the analysis was done for three consecutive time periods: 1973-79, 1980-89, and 1990-99. Mean birth weight was 2553 g (SD 640), and mean gestational age was 39 weeks (SD 4). Forty-two newborns (40%) had one or more associated congenital malformations, and 30% had associated cardiac malformations. There was no change in incidence of associated anomalies over the three time periods studied. Mortality of patients decreased from 33% to 14% (p = 0.048). There was a significant association between the presence of a major cardiac malformation and survival (survival: 88% vs. 57%, p = 0.004). Analysing the three different time periods separately reveals that cardiac disease was not a significant risk factor in the first period but became significant in the period from 1980-99 (relative risk: 6.76, 95% CI 1.44-31.77). Birth weight was significantly higher in infants who survived (2626 g, SD 642) compared with those who died (2290, SD 570, p = 0.028). This effect, however, is mainly based on the difference during the first period and is lost later. Early and late postoperative complications occurred in 44/102 patients. Strictures developed in 33/91 patients who survived the first month of life (33%). The rate of symptomatic strictures decreased significantly over the three time periods, from 50% to 23% (p = 0.022). In summary, this study shows no significant change in patient characteristics over the last 3 decades, but mortality and postoperative complication rates decreased, and associated cardiac anomalies became the far most important risk factor for mortality.

Background: Most girls with recurrent urinary tract infections do not have major urinary tract abnormalities. Recent studies focus on predisposing behavioral and functional abnormalities: infrequent voiding, inadequate fluid intake, stool retention, poor genital hygiene and voiding dysfunction., Methods: Complete history, bladder and bowel questionnaire, physical examination, voiding-drinking diary, sonography and uroflowmetry were used to assess infrequent voiding, functional stool retention, poor fluid intake, inadequate hygiene, or voiding dysfunction in girls referred for evaluation of three or more symptomatic urinary tract infections (with a first infection at the age of more than 36 months)., Results: A total of 141 girls aged 3.9 to 18 years were evaluated between 1996 and 1999; 212 abnormalities were noted in 120 patients: infrequent voiding (isolated, 16; combined with other abnormalities, 47), poor fluid intake (isolated, 10; combined, 50), functional stool retention (isolated, 5; combined, 25), inadequate hygiene or toilet habits (isolated, 3; combined, 24), dysfunctional voiding (isolated, 15; combined, 10), bladder overactivity (isolated, 5; combined, 2)., Conclusions: Most girls referred for evaluation of three or more urinary tract infections have host-mediated predisposing abnormalities: infrequent voiding, poor fluid intake, functional stool retention or voiding dysfunction. Poor genital hygiene and toilet habits were almost always combined with other abnormalities, suggesting that infections are not necessarily related to poor genital hygiene or toilet habits. Two or more indications of predisposing behavior often concur in the same patient.

Methods: In order to assess intermediate-term speech outcome after pharyngeal flap surgery for velopharyngeal dysfunction in children with cleft palate between 1980 and 1998, their pre- and postoperative speech performance was analyzed in a blinded fashion by speech pathologists and adult lay people. Speech was evaluated on the basis of tape recordings with regard to resonance, intelligibility, articulation, voice and secondary speech disorders., Results: Twenty-three patients could be evaluated. Both lay assessors and speech pathologists noted a significant improvement in speech performance after pharyngeal flap surgery. The percentage of children who improved was 83% (19/23, 95% confidence interval: 0.68-0.98, p = 0.002) when rated by lay people, and 87% (20/23, CI 0.73-1.01, p < 0.0001) when rated by professionals. Rated on a 5-point scale, the mean improvement per speech characteristic was 0.52 +/- 0.32 scale points when judged by lay people, and 0.75 +/- 0.8 points when judged by experts. Experts considered none of the children to have normal speech after surgery. Agreement with regard to outcome between lay people and speech pathologists occurred in 87% of the patients., Conclusion: The cranially based pharyngeal flap can improve speech performance in cleft palate children with chronic velopharyngeal insufficiency. However, it cannot be expected that this type of surgery will result in normal speech., (Copyright 2002 S. Karger AG, Basel)

Prophylactic antibiotics are widely used during surgery, above all for clean-contaminated or contaminated procedures. Because factors other than the degree of contamination play a critical role in regard to postoperative infectious complications, it is not evident that recommendations for antibiotic prophylaxis for an adult population can be transferred to children. The aim of the study was to analyze the incidence of postoperative infections in children undergoing appendectomy for suspected appendicitis to evaluate critically the effectiveness of prophylaxis. The charts of all children undergoing appendectomy between 1988 and 1998 were analyzed. In general, appendectomies were performed without antimicrobial prophylaxis. If a perforated appendicitis was found at operation, antibiotics were given intraoperatively. Postoperative infectious complications were defined as wound infections, intraabdominal infections, or prolonged postoperative pyrexia. During the study period of 10 years, 954 patients underwent appendectomy. In 24% of cases the appendix was perforated. Patients received prophylactic antibiotics at the surgeon's discretion. These patients were excluded from further analysis. Among those with non-perforated appendicitis (n = 633), Infectious complications occurred in 19 (3%). Analyzing subgroups according to histologic diagnosis, the incidence was 4.2% (16/382) for gangrenous appendicitis and 1.2% (3/251) for simple appendicitis or normal appendix. These figures are clearly lower than those reported from an adult population, indicating that results from adults cannot a priori be transferred to children, and that general recommendations concerning antimicrobial prophylaxis must be considered carefully for this age group.

The outcome of patients with thoracic or thoracoabdominal aortic aneurysm is often determined by the concomitant coronary artery disease. Two patients with thoracic and thoracoabdominal aortic aneurysm and concomitant single-vessel coronary artery disease underwent combined myocardial revascularization and repair of aortic aneurysm. The operations were performed through a left thoracotomy and thoracoabdominal incision with distal aortic perfusion using a partial femoro-femoral bypass and selective right lung ventilation. Coronary anastomoses were performed on the beating heart, and the aneurysm was replaced with a woven Dacron tube graft.

Background: To maintain good exposure during major video-assisted thoracic surgery it is necessary to deflate completely the ipsilateral lung. However, little is known about the effects of one-lung ventilation (OLV) on pulmonary function in newborn patients., Methods: Ten neonatal domestic pigs with a mean age of 6+/-0.6 days were intubated and ventilated in pressure-controlled mode (inspired oxygen fraction=1.0). One-lung ventilation was maintained for 120 minutes. Serial measurements of hemodynamics and gas exchange were done before, during, and until 90 minutes after OLV. Pulmonary function testing was performed before and after OLV for each lung separately., Results: With the inspired oxygen fraction set at 1.0, arterial oxygen saturation remained stable at 100% during OLV. Venous admixture and alveolar-arterial oxygen tension gradient increased slightly from the baseline value of 2.6% +/-0.3% to 3.8%+/-0.3% during OLV (mean+/-standard error of the mean; p=0.02), and from 358+/-28 to 407+/-18 mm Hg (not significant), respectively. Both values returned to baseline during the subsequent ventilation of both lungs. Static compliance and resistance of the ventilated lung did not change. Compliance of the collapsed lung decreased after reexpansion from 0.42+/-0.07 to 0.29+/-0.06 mL x cm H2O(-1) x kg(-1), p=0.008). Resistance remained unchanged (0.22+/-0.02 versus 0.25+/-0.05 cm H2O x L(-1) x s(-1); not significant)., Conclusions: There were only minor effects on pulmonary function during and after OLV in the neonatal piglet. Alterations in gas exchange during OLV were minimal. Prolonged collapse of the lung with subsequent reexpansion was associated with a slight decrease in compliance, indicating some mild lung injury.

Background: There is some evidence that continuous warm blood cardioplegia offers good myocardial protection; however, the effects of interrupting cardioplegia remain controversial. To study this, we compared the effects of continuous and intermittent antegrade warm (37 degrees C) blood cardioplegia on functional recovery after prolonged cardiac arrest (180 minutes)., Methods: Twenty-four juvenile pigs were randomly assigned into four groups. Group 1 received continuous cardioplegia, group 2 underwent several periods of 15 minutes of cardioplegia interrupted by 5 minutes of normothermic ischemia, and group 3 underwent several periods of 10 minutes of cardioplegia interrupted by episodes of 10 minutes. The hearts of group 4 received no cardioplegia. Left ventricular systolic function was assessed from fractional left ventricular shortening and percentage left ventricular wall thickening, and left ventricular diastolic function was determined from the time constant of relaxation and the constant of myocardial stiffness., Results: Systolic and diastolic functions were slightly depressed 1 and 2 hours after cross-clamp removal in all four groups, without significant differences among the groups., Conclusions: These data suggest that antegrade warm blood cardioplegia can be interrupted for up to 10 minutes without obvious negative effects on left ventricular function in the normal myocardium, provided that the intermittent doses of cardioplegia are sufficient to restore the metabolic demands of the arrested myocardium.

Phrenic nerve injury with resulting diaphragm paralysis occurred in 25 (1.5%) of 1,656 cardiac surgical procedures in children during a 10-year period. Phrenic nerve injury was most commonly noted in patients who had undergone previous cardiac surgery (16 of 165, 10%; P < .0001), typically after a previous Blalock-Taussig shunt (10 of 53, 19%; P = .007). Plication of the diaphragm (7 thoracic, 4 abdominal) was performed in 11 patients (44%). Indications for plication were inability to wean from mechanical ventilation (5 patients) and persistent or recurrent respiratory distress (6 patients). The patients who needed diaphragm plication were significantly younger than those who were managed conservatively (median, 11 months [4 days to 23 months] versus 20 months [4 months to 16 years]; P = .01). All patients older than 2 years were extubated within 3 days (mean, 1.5 days) and did not need any surgical intervention. The median follow-up period was 3.2 years, and no patient has had recurrent respiratory problems. There were no deaths as a direct result of phrenic nerve injury. Phrenic nerve injury after cardiac surgery is a serious complication that often leads to respiratory insufficiency in patients under than 2 years of age. For such patients, early diaphragm plication is a simple and effective procedure that prevents the complications of prolonged mechanical ventilation.

An extra corporeal venovenous bypass circuit (right atrium to pulmonary artery), including an intravascular gas exchanger in a blood chamber with a variable inner diameter, was developed for ex vivo evaluation of the host vessel diameter/intravascular oxygen transfer relationship. Three host vessel diameters mimicking different configurations of the caval axis were studied in three bovine experiments (body weight 82 +/- 3 kg). Blood flow was 3,000 ml/min and device oxygen inflow was 2,300 ml/min. Serial blood samples were taken for 26 mm, 23 mm, and 20 mm inner blood chamber diameters after hemodynamic stabilization before and after exposure of the circulating blood to the intravascular gas exchanger (sampling ports at blood chamber inlet and outlet). Measured oxygen saturation at the blood chamber inlet was 25.0 +/- 11.7% for the 26 mm diameter as compared to 31.7 +/- 12.6% for 23 mm, and 28.7 +/- 9.2% for 20 mm. At the outlet, the corresponding O2 saturations were 34.5 +/- 11.5% for 26 mm, 42.9 +/- 8.8% for 23 mm, and 43.2 +/- 6.2 for 20 mm. Total O2 transfer was 24.9 +/- 11.5 ml/min for 26 mm, 31.9 +/- 7.4 ml/min for 23 mm, and 35.9 +/- 12.2 ml/min for 20 mm (p < 0.05). Likewise, O2 transfer rate was 8.3 +/- 3.8 ml/L, 10.6 +/- 2.4 ml/L, and 12.0 +/- 4.0 ml/L (p < 0.05). Parallel analyses of total CO2 transfer and CO2 transfer rates provided less consistent findings. At 3 L/min, the pressure drop between the inlet and outlet of the blood chamber was 12 +/- 3 mmHg for 26 mm, 26 +/- 1 mmHg for 23 mm, and 38 +/- 2 mmHg for 20 mm diameters (p < 0.001). The authors conclude that oxygen transfer of a given intravascular gas exchanger appears to be indirectly proportional to the host vessel diameter. Increasing blood pressure gradient as a function of decreasing diameter has to be considered in clinical application.

To test the hypothesis that acute lung injury during cardiopulmonary bypass (CPB) is related to the activation of neutrophils and the body temperature during bypass, we determined the differential WBC count, plasma elastase concentrations, and lung function before, during, and after CPB in 38 patients undergoing elective coronary artery bypass surgery. The patients were randomly assigned to receive either normothermic (n = 19, rectal temperature: 35.9 +/- 0.1 degrees C, mean +/- SE) or hypothermic (n = 19, 29.2 +/- 0.5 degrees C) CPB. The cellular response to the extracorporeal circulation was significantly delayed in the hypothermic group with a later onset of neutrophilia and a later increase in plasma elastase levels during bypass. Lung function deteriorated significantly after CPB as assessed by respiratory index, alveolar-arterial oxygen gradient, and intrapulmonary shunt, independent of bypass temperature. There was a positive correlation between peak elastase concentrations and postoperative respiratory index as well as intrapulmonary shunt (R2 = 0.5, p = 0.002 and R2 = 0.45, p = 0.003, respectively). Besides peak plasma elastase levels, multiple regression revealed no significant influence of other independent factors on postoperative lung dysfunction in our patients.

Background: The intravascular gas exchanger is a lung assist device for augmentation of gas exchange in critically ill patients with severe acute respiratory failure. These patients often require inotropic support therapy due to the cardiovascular instability that almost inevitably accompanies severe respiratory failure., Methods: We investigated the interaction of vasoactive medication (dopamine, nitroglycerin, and noradrenaline) with the gas exchange performances of the intravascular gas exchanger in a bovine experimental model., Results: Dopamine administration highly increased cardiac output, caval flow rates, and diameter of vena cava inferior. These effects resulted in a significant increase in oxygen transfer (baseline, 35 +/- 6 mL/min versus 153 +/- 27 mL/min at 20 micrograms.kg-1.min-1 of dopamine, p < 0.001) and carbon dioxide elimination (baseline, 35 +/- 2 mL/min versus 47 +/- 4 mL/min at 20 micrograms.kg-1.min-1 of dopamine, p < 0.001). Administration of nitroglycerin did not cause significant changes of the hemodynamic parameters nor did it affect the oxygen transfer or carbon dioxide elimination. Noradrenaline caused a moderate increase in cardiac output and caval flow, but no changes of caval diameter. hemodynamic changes were accompanied by an increase in oxygen transfer from 38 +/- 5 mL/min to 68 +/- 7 mL/min (p < 0.01) and carbon dioxide elimination from 33 +/- 1 mL/min to 40 +/- 1 mL/min (p = 0.03). The multiple regression analysis showed significant influence of changes in cardiac output on oxygen transfer (p < 0.001) and carbon dioxide elimination (p = 0.004). The administration of vasoactive drugs induced slight changes in caval diameter that did not significantly affect the gas transfer., Conclusions: The results from our study reveal the major influence of cardiac output on efficiency of gas transfer of the intravascular oxygenator.

The accumulation of activated leukocytes in the pulmonary circulation plays an important role in the pathogenesis of lung dysfunction associated with cardiopulmonary bypass. Animal studies have demonstrated that the elimination of leukocytes from the circulation reduces postoperative lung injury and improves postoperative pulmonary function. We conducted a prospective randomized clinical study to evaluate whether postoperative lung function could be improved by use of a leukocyte filter during cardiopulmonary bypass. Elective coronary artery bypass grafting was done with a leukocyte-depleting arterial blood filter incorporated in the extracorporeal circuit (14 patients, leukocyte filter group) or without the filter (18 patients, control group). Blood samples collected at intervals before, during, and after operation were used for analysis of blood cell counts, elastase concentrations, and arterial blood gases. The use of the leukocyte filter caused no significant reduction in leukocyte count (p = 0.86). There were no differences in postoperative lung function between the groups, as assessed through (1) oxygenation index (290 for leukocyte filter group compared with 329 for control group, 95% confidence interval, 286 to 372, p = 0.21), (2) pulmonary vascular resistance (p = 0.10), and (3) intubation time (16.6 hours for leukocyte filter group versus 15.7 hours for control group, 95% confidence interval, 12.1 to 19.1 hours, p = 0.72). The levels of neutrophil elastase were significantly higher at the end of cardiopulmonary bypass in the leukocyte filter group (460 microgram/L in leukocyte filter group versus 230 microgram/L in control group, 95% confidence interval, 101 to 359 microgram/L, p = 0.003). We conclude that the clinical use of the present form of leukocyte-depleting filter did not improve any of the postoperative lung function parameters analyzed in this study.

Objective: To compare the methods for continuous and bolus thermodilution cardiac output measurements., Design: In vivo and in vitro experimental studies., Setting: Surgical research division in a university hospital., Subjects: Eight calves and flow bench model., Interventions: Data were collected in vivo from eight calves instrumented with pulmonary artery catheters, which allowed both continuous and bolus thermodilution measurements. The pulmonary artery catheter was placed through the external jugular vein. All in vitro measurements were performed using a flow bench model., Measurements and Main Results: A total of 232 bolus and continuous thermodilution measurements were analysed in vivo to determine the degree of agreement between the two methods. The absolute measurement bias was 0.14 L/min with 95% confidence limits ranging from -0.83 to 1.15 L/min. In vitro analysis of 576 measurements at six different temperature points (range 31 degrees to 41 degrees C), using clinically relevant flows (2 to 9 L/min), showed overestimation of flow values using continuous and bolus thermodilution methods. However, the continuous method showed better accuracy by a lower degree of overestimation. Systematic error was 9.7 +/- 8.4 (SD) % for continuous and 11.1 +/- 6.3% for the bolus method (p < .001). This effect was especially evident at lower flow rates. The influence of various temperatures on the accuracy and reproducibility of both methods of measurement was statistically significant but not clinically relevant. The infusion of lactated Ringer's lactate solution (infusion rates 100 to 1000 mL/hr) affects both methods at a low flow rate of 2 L/min, without causing a significant effect on continuous measurement at a higher flow rate (4 L/min). Shunting of 50% of circulating volume to the distal part of the thermal filament of the pulmonary catheter impaired the accuracy of continuous measurement without affecting results from bolus measurements (systematic error -26.8 +/- 8.2% for continuous and -5.2 +/- 4.1% for bolus thermodilution)., Conclusions: Continuous thermodilution cardiac output measurement provided higher accuracy and greater resistance to thermal noise than standard bolus measurements. The correct placement of the catheter is essential for precise measurements.

To evaluate the influence of perfusion temperature on systemic effects of cardiopulmonary bypass (CPB), 30 patients undergoing elective coronary artery bypass grafting were randomly assigned to either normothermic (warm, n = 14, 36 degrees C) or hypothermic (cold, n = 16, 28 degrees C) CPB. Serial hemodynamic measurements and blood samples were obtained before, during and after the CPB procedure. During CPB, there were no differences between both groups in the need for vasopressors (norepinephrine, phenylephrine), urinary output, or fluid balance. In the early postoperative period, normothermic CPB patients had significantly lower systemic vascular resistance and higher cardiac index measurements (mean +/- standard error: systemic vascular resistance, 880 +/- 27 versus 1,060 +/- 57 dyne.s.cm-5, p = 0.025; cardiac index, 3.6 +/- 0.1 versus 2.9 +/- 0.1 L.min-1.m-2, p = 0.01) without differences in the administration of vasoactive drugs. Blood loss was significantly higher in patients after hypothermic CPB (median [range] body surface area: 370 [180-560] versus 490 [280-2,120] mL/m2, p = 0.0006), with a greater need for transfusion of erythrocytes and fresh frozen plasma. Plasma levels of tumor necrosis factor and soluble tumor necrosis factor receptors increased during and after CPB, independent of perfusion temperature. This study suggests a significant influence of CPB temperature and respective perfusion management on postoperative hemodynamics and blood loss. Normothermic CPB is not associated with additional systemic adverse effects.

The hemopump HP 31 is an improved version of a catheter-mounted, transvalvular, left ventricular assist device, which can be placed into the left ventricle through the ascending aorta. The purpose of this study was to examine the influence of hematocrit and afterload on the pump flow. The hemopump was tested using a flow bench model filled with heparinized bovine blood. The measurements were performed at four various hematocrit values: 16%, 24%, 32%, and 40%. The pump flow was measured at each hematocrit value under increasing afterload pressures (40-120 mm Hg), by all pump speed levels (n = 7). The average pump flow at highest pump speed and lowest afterload was 5.1 +/- 0.3 l/min (mean +/- standard deviation). The influence of afterload on the pump flow was statistically significant (p < 0.001). The highest afterload pressure of 120 mm Hg caused a reduction in pump flow of 24 +/- 5%. The alterations of hematocrit values caused no statistically significant influence on the pump flow (p = 0.72). The results of our study enabled the construction of the nomogram for the in vivo determination of the pump flow. The in vivo performances of the hemopump can be improved through the afterload reduction, especially in the weaning phase of treatment. The oxygen delivery can be improved through the increase in hematocrit values without significant impairment of the pump flow.

We examined the effectiveness of inhaled nitric oxide (NO) as a selective pulmonary vasodilator in acute pulmonary hypertension in an in vivo canine model with fixed cardiac output. In 5 dogs, total right heart bypass was instituted, and pulmonary hypertension was induced by infusion of the thromboxane analogue U-46619. During U-46619 infusion, NO was administered at 10 and 40 ppm for 5 minutes followed by breathing of the oxygen mixture without NO. Pump flow was held constant during the experiment. Infusion of the thromboxane analogue resulted in an increase in pulmonary vascular resistance and systemic vascular resistance from 147 +/- 83 to 740 +/- 126 dyne.s.cm-5 and from 1,720 +/- 113 to 2,407 +/- 232 dyne.s.cm-5, respectively. During inhalation of 10 ppm NO, pulmonary vascular resistance significantly decreased to 613 +/- 55 dyne.s.cm-5 (p < 0.05) and further decreased to 527 +/- 163 dyne.s.cm-5 with 40 ppm NO inhalation (p < 0.05). Systemic vascular resistance did not change during NO treatment (2,300 +/- 70 dyne.s.cm-5 during 40 ppm NO). There was no increase in intrapulmonary shunting or methemoglobin levels during NO inhalation. In this setting, with a constant cardiac output throughout the experiment, NO acted as a selective pulmonary vasodilator without altering systemic vascular resistance. However, induced pulmonary vasoconstriction was only partially reversed by NO inhalation.

The intravascular oxygenator is a newly developed device for intracaval gas exchange in critically ill patients with respiratory failure. In an experimental ex vivo model, performance characteristics of the intravascular oxygenator/carbon dioxide removal device were studied. With a mean hemoglobin concentration of 6.2 +/- 1.9 g/dL (mean +/- standard deviation), total O2 transfer was 21.8 +/- 4.8 mL/min at a blood flow of 1 L/min, 37.0 +/- 12.6 mL/min at 2 L/min, at 2 L/min, and 47.5 +/- 16.7 mL/min at 3 L/min. Total CO2 transfer was 27.3 +/- 6.6 mL/min at a blood flow of 1 L/min, 38.6 +/- 8.9 mL/min at 2 L/min, and 40.4 +/- 9.3 mL/min at 3 L/min. In contrast to total gas transfer, O2/CO2 transfer rates (mL/L) diminished significantly with increasing blood flow. In addition, there was a negative correlation between O2 transfer rate and venous O2 partial pressure (r = -0.73; p < 0.0001), a positive correlation between CO2 transfer rate and venous CO2 partial pressure (r = 0.65; p < 0.0001), and a positive correlation between O2 and CO2 transfer rates and blood hemoglobin level (r = 0.57 [p < 0.01] and r = 0.70 [p < 0.01], respectively). These results demonstrate that the behavior of the intravascular hollow-fiber oxygenator is similar to that of the classic membrane oxygenator used for cardiopulmonary bypass: total gas transfer correlates directly with blood flow and venous CO2 partial pressure and indirectly with venous O2 partial pressure. The O2 and CO2 transfer rates increase significantly with increasing hemoglobin content of the blood.

Activation of leukocytes (especially neutrophils) during cardiopulmonary bypass (CPB) causes a reperfusion injury through the release of oxygen free radicals and formation of microvascular occlusions. Leukocyte filtration during CPB could solve these drawbacks. We investigated the selectivity of leukocyte filtration by fifteen patients undergoing coronary artery bypass surgery. Leukocyte depleted patients (n = 8) had a leukocyte filter incorporated in the bypass circuit. We evaluated the number of lymphocytes, neutrophils and platelets as well as hematocrit values at following time points: a) before CPB, b) 15 min after the start of CPB, c) before the administration of protamin and d) 3 hours after the CPB. No statistically significant changes of hematocrit values, lymphocyte or platelet counts between control and leukocyte depleted group of patients were observed. However, the use of leukocyte filter caused significant decrease in number of circulating neutrophils at 15 min after begin of CPB (1.20 +/- 0.17 x 10(9)/l for leukocyte depleted patients and 1.90 +/- 0.42 x 10(9)/l for control group of patients, p < 0.05). Our temporary results indicate the selectivity of leukocyte filtration during the cardiopulmonary bypass.

Unlabelled: There is some evidence of improved myocardial protection with warm continuous blood cardioplegia. Warm cardioplegia however implies warm (normothermic) cardiopulmonary bypass (CPB). We evaluated retrospectively the influence of bypass temperature on the intra- and postoperative course of 121 patients, operated on for valvular and/or coronary artery disease. Only elective procedures with continuous blood cardioplegia were included. The patients were divided in two groups: warm group (n = 78): normothermic CPB (venous temperature > 33 degrees C) cold group (n = 43): hypothermic CPB (< 33 degrees C)., Results: normothermic CPB resulted in a significantly shorter CPB time (84 + 3 min vs. 98 +/- 6 min, p = 0.02, mean +/- 1 standard error of the mean). In addition there was a higher need for vasoconstrictive drugs during cold CPB (Noradrenalin: 19 +/- 3 micrograms vs. 90 +/- 32 micrograms, p = 0.003). There was no difference in enzyme levels on the first postoperative day (amylase, creatinkinase, creatinin), in postoperative complication rate (resuscitations, rethoracotomies, cerebrovascular incidents) and mortality (warm 3% vs. cold 2%) between the two groups. The postoperative time until extubation however was significantly shorter in the warm group (33 +/- 5 h vs. 60 +/- 11 h, p = 0.04)., Conclusion: there is no evidence of increased morbidity due to normothermic CPB. The shorter time until extubation may be due to a improved postoperative lung function and/or a more stable hemodynamic postoperative course after normothermic CPB.

Several surgical approaches have been reported for operative correction of complex or recurrent form of aortic coarctation. In this study we report our experience with extra-anatomic ascending-supraceliac abdominal bypass grafting for complicated form of aortic coarctation in 12 patients. All patients survived the operations, without late mortality. This type of surgical correction of complex or recurrent form of coarctation is a safe and effective procedure.