Altered Cisatracurium Pharmacokinetics and Pharmacodynamics in Patients with Congenital Heart Defects.

The neuromuscular blocking agent cisatracurium is frequently used adjunctively in anesthesia to facilitate endotracheal intubation and to provide muscle relaxation during surgery. We aimed to determine the pharmacokinetics (PK)/pharmacodynamics (PD) of cisatracurium in patients with congenital heart defects (CHDs), such as ventricular septal defects and atrial septal defects, and to assess the effects of CHDs on the PK/PD profiles of cisatracurium. A modified two-compartment model with drug clearance from both compartments was best fitted to the PK data to determine the PK parameters. The model suggested that septal defects significantly lowered the rate of cisatracurium distribution from the central to peripheral compartment. The intercompartment rate constants k12 and k21 were significantly reduced (35%-60%, P < 0.05) in patients with ventricular septal defects and in patients with atrial septal defects compared with control patients. Consistently, septal defects caused a marked increase (160%-175%, P < 0.001) in the distribution half-life. Furthermore, significantly delayed pharmacodynamic responses to cisatracurium were observed in patients with septal defects. The onset time (i.e., the time to maximal neuromuscular block) was prolonged from 2.2 minutes to 5.0 minutes. PK/PD modeling suggested that reduced concentrations of cisatracurium in the effect compartment due to poorer distribution were the main cause of lagged pharmacodynamic responses. In conclusion, cisatracurium PK/PD were significantly altered in patients with septal defects. Our study should be of use in clinical practice for the administration of cisatracurium to patients with CHDs.

Changes in Plasma Atrial and Brain Natriuretic Peptide Levels in Children Undergoing Surgical Isolated Atrial Septal Defect Closure.

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase after cardiopulmonary bypass (CPB) in pediatric patients. However, the exact reason for the postoperative increase remains unclear. This study elucidated the perioperative changes in plasma natriuretic peptide levels in children undergoing surgical isolated atrial septal defect (ASD) closure. Between 2010 and 2012, 24 pediatric patients (median 7.1, range 2.7-15.7 years) underwent surgery for simple ASD using CPB under ventricular fibrillation (Group A, 16 patients) or under cardiac arrest (Group B, 8 patients). Natriuretic peptide levels were measured before surgery, on postoperative day 0, 1, 3, and at the first outpatient visit. The pulmonary to systemic blood flow ratio (Qp/Qs) was estimated by echocardiography using an index of right ventricle end-diastolic area. Preoperative natriuretic peptide levels positively correlated with the Qp/Qs. Plasma ANP levels peaked on postoperative day 0, and its values were higher in Group A than in Group B patients (p < 0.001). Plasma BNP levels increased significantly in both Groups on postoperative day 1, and its values were significantly greater in Group A than in Group B patients (p = 0.007). There was a weak negative correlation between the amount of postoperative increase in natriuretic peptide levels and the Qp/Qs. There was no appreciable difference in the acute postoperative clinical course and echocardiographic parameter on postoperative day 3 between Group A and B patients. In conclusion, acute postoperative natriuretic peptide levels after isolated ASD closure were multifactorial, and they might be unreliable for predicting clinical outcomes.

Platelet activation through the efficacy of aspirin in congenital heart disease patients undergoing transcatheter closure of atrial septal defects or ventricular septal defects.

OBJECTIVES: The aim of this study is to compare preoperative and postoperative conditions of GMP-140 concentration, the aggregation and activation of platelets in congenital heart disease patients undergoing transcatheter closure of atrial septal defects (ASDs) or ventricular septal defects (VSDs), and the appropriate dose of aspirin of patients after transcatheter closure. MATERIALS AND METHODS: Thirty-two consecutive patients with ASD (n=16) and VSD (n=16), as shown on transthoracic echocardiography and right heart catheter examination, were treated with a percutaneous catheter occlusion. The patients comprised 13 males and 19 females with a mean age of 25.6±9.15. Patients were randomly assigned into two groups within half an hour after ASD or VSD occlusion. Group A cases were treated with 3 mg/kg/day enteric-coated aspirin tablets for 6 months, while patients in group B received 5 mg/kg/day enteric-coated aspirin tablets for 6 months. RESULTS: The rates of platelet aggregation (PAG) in the immediate postoperative ASD/VSD occlusion were significantly higher than those in the preoperative ASD/VSD occlusion (adenosine diphosphate [ADP]-induced PAG: 64.98%±7.65% vs. 86.33%±6.54%, p<0.05; arachidonic acid [AA]-induced PAG: 62.92%±9.11% vs. 86.96%±6.90%, p<0.05, respectively). After treatment with aspirin, the GMP-140 levels presented a clearly defined downward trend in the immediate postoperative period (3 mg/kg/day aspirin: 18.30±3.42 vs. 13.37±1.80, p<0.05; 5 mg/kg/day aspirin: 18.30±3.42 vs. 13.41±1.60, p<0.05), but no obvious difference was observed considering the GMP-140 levels in the 4 days after occlusion (all p>0.05). CONCLUSION: Our study showed that the GMP-140 serum level and PAG were increased after ASD and VSD occlusion, and patients may have a trend of decreased GMP-140 serum levels after the ASD or VSD occlusion surgeries after the treatment with aspirin. Daily oral administration of 3 and 5 mg/kg/day aspirin can induce a significant decrease in PAG of patients after VSD/ASD occlusion.

Mean platelet volume levels predict pulmonary artery hypertension in patients with atrial septal defect.

INTRODUCTION: Some reports have shown increased platelet aggregation and activation in patients with pulmonary artery hypertension (PAH). Mean platelet volume (MPV) is a simple and easy method of assessing platelet function. We aimed to investigate the mean platelet volume levels in patients with atrial septal defect (ASD) and the association between MPV levels and pulmonary artery hypertension. METHOD: One hundred and forty consecutive patients (42 males and mean age 35 +/- 9 y) and forty healthy controls (15 males and mean age 35 +/- 4 y) were enrolled in the study between December 2008 and February 2011. RESULTS: The ASD group demonstrated a significantly higher right ventricular size and pulmonary artery pressure than the control group (42 +/- 4 mm vs. 36 +/- 3 mm and 43 +/- 12 mmHg vs. 32 +/- 11 mmHg; P < 0.001 and P < 0.001, respectively). MPV levels were higher in the ASD group than the control group (9.3 +/- 1.2 fl vs. 8.6 +/- 0.8 fl, P < 0.001). There was a significant, positive correlation between MPV and systolic pulmonary artery pressure (PAP) (r = 0.542 and P < 0.001) in the ASD group. MPV was also significantly correlated with right ventricular size but not ASD diameter in the ASD group (r = 0.441, P < 0.001 and r = 0.126, P = 0.268, respectively). In receiver operating characteristics curve analysis, the cut-off value of MPV levels was > 8.7 fl and had 82% sensitivity and 63% specificity in predicting pulmonary artery hypertension. CONCLUSION: In the present study, we found that MPV levels, an indicator of platelet activation, were significantly higher in patients with ASD and correlated with systolic pulmonary artery pressure and right ventricular diameter.

Circulating ghrelin was negatively correlated with pulmonary arterial pressure in atrial septal defect patients.

BACKGROUND: Ghrelin was found to attenuate the magnitude of pulmonary arterial hypertension and pulmonary vascular remodeling in rats. The objective of this study was to explore the fasting plasma ghrelin level and the relationships between ghrelin and pulmonary arterial pressure (PAP) in atrial septal defect (ASD) patients with pulmonary arterial hypertension (PAH). METHODS: Fasting plasma ghrelin, obestatin, and insulin levels were measured by enzyme linked immunosorbent assay (ELISA) method in ASD patients with or without PAH according to the manufacturer's instructions. Insulin resistance was calculated by the homeostasis model of assessment for insulin resistance (HOMA-IR) approach, calculated as fasting insulin (microunits/ml)× fasting blood glucose (mmol/L)/22.5. Comparisons between the parameters of patients with PAH and those of patients with normal PAP were performed with an unpaired Student's t test. The relationships between ghrelin and various clinical parameters were examined by bivariate correlations and multiple regression analysis. RESULTS: We found that the fasting plasma ghrelin level and the ratio of ghrelin to obestatin were significantly lower in the PAH group compared with the control group ((582.4±12.8) pg/ml vs. (1045.2±95.5) pg/ml, P < 0.05 and 30.5±4.9 vs. 70.0±9.7, P < 0.01). The fasting plasma obestatin level was higher in the PAH group compared with the control group, but the difference between them was not significant ((23.2±3.1) pg/ml vs. (16.3±1.6) pg/ml, P > 0.05). In a multiple regression model analysis, only mean PAP was an independent predictor of ghrelin and the ratio of ghrelin to obestatin (standardized coefficient = -0.737, P < 0.001 and standardized coefficient = -0.588, P = 0.006, respectively). CONCLUSION: Ghrelin is negatively correlated with mean PAP and this suggests that circulating ghrelin might predict the severity of pulmonary hypertension in ASD patients with PAH.

Use of dopamine infusion improved oxygenation in a patient of Ebstein's anomaly with atrial septal defect.

We present the successful perioperative management of an adult patient with Ebstein's anomaly for abdominal rectopexy surgery. The patient developed mild hypotension and a fall in peripheral oxygen saturation (SpO 2 ) after administration of a graded epidural block. Correction of the fall in the blood pressure; however, did not improve the SpO 2 . The patient was administered an intravenous infusion of dopamine to improve the cardiac output and this led to improvement in the SpO 2 .

Neurohormonal and cytokine fluctuations following transcatheter closure for an atrial septal defect.

INTRODUCTION: Inflammation and neurohormonal activation are considered to be involved in the development of earlier and/or later complications in congenital heart disease patients, even after a successful repair of the lesion. It is not yet clarified what is the role of the therapeutic interventions in the occurrence of such a response and how it could be associated with possible postoperative complications. AIM: We sought to assess the inflammatory and neurohormonal response to transcatheter closure of secundum type atrial septal defects (ASD) over a six-month follow-up period. We also evaluated the association between the respective markers and catheterization data as well as echocardiographic measurements. METHODS: Plasma concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), N-terminal-proatrial natriuretic peptide (NT-proANP) and N-terminal-probrain natriuretic peptide (NT-proBNP) were assessed and echocardiographic measurements were performed in twenty-eight patients with atrial septal defect prior to, and at the first, second and sixth months post transcatheter closure. Thirty-three age-matched healthy volunteers were also enrolled. RESULTS: IL-6 plasma levels, although higher preoperatively, [physical logarithm (ln) IL-6: 3.37±0.66 vs 2.92±0.44 pg/ml, p=0.015], reached control levels postoperatively, at the end of the third month, whereas TNF-α and IL-10 were not influenced by the procedure. NT-proANP levels were elevated preoperatively compared to the control group (ln NT-proANP 3.78±0.572 vs 3.48±0.30, p=0.031), with a further significant increase during the 1st month (ln NT-proANP 3.78±0.572 vs 4.2±0.42, p=0.006), following the pattern of the left atrial volume enlargement, and remained high even 6 months after the procedure .On the other hand, the initially normal concentrations of NT-proBNP, after a transient significant increase during the first month postoperatively (ln NT-proBNP 3.56±0.94 vs 4.58±0.91, p<0.0001) returned to the controls' levels at the end of the third month. Preoperative concentrations of NT-proANP positively correlated with NT-proBNP concentrations and pulmonary to systemic flow ratio (Qp/Qs). CONCLUSIONS: Transcatheter closure could improve, on a mid- term basis, the inflammatory process but natriuretic peptides' secretion continues in parallel with left atrial volume increase. Further follow up is required to determine the long-term progress of the inflammatory and neurohormonal response to the procedure.

Association of plasma B-type natriuretic peptide levels with shunt size in young adults with atrial septal defect.

OBJECTIVE: This study was designed to investigate the validity of brain natriuretic peptide (BNP) levels for the estimation of the shunt size in young adults with atrial septal defect (ASD), and to determine the relationship between BNP levels and echocardiographic parameters of right heart chambers. METHODS: Fifty-six patients with ASD (mean age 22.9 ± 2.0 years) were studied. The control group consisted of 31 age-gender matched healthy volunteers (mean age 22.7 ± 1.9 years). Coventional echocardiography, tissue Doppler imaging (TDI) and plasma BNP level measurement was performed in all participants. The ratio of pulmonary to systemic blood flow (Qp/Qs) was measured noninvasively using transthoracic echocardiography. RESULTS: Plasma BNP levels were significantly higher in ASD patients than in controls (42.9 ± 29.4 vs. 8.3 ± 2.6 pg/mL, P < 0.05). Pulmonary artery pressure (PAP) (P = 0.0001), right atrium (RA) volume (P = 0.0001), and right ventricular end-diastolic volume (RVEDV) (P = 0.0001) values were higher in ASD patients. There was a powerful correlation between plasma BNP levels and Qp/Qs ratio (r = 0.71, P < 0.0001). The plasma BNP levels significantly correlated with PAP (r = 0.61, P < 0.0001), RA volume (r = 0.54, P < 0.0001), RVEDV (r = 0.55, P < 0.0001), and right ventricular myocardial performance index (r = 0.50, P < 0.0001). CONCLUSION: This study shows that there is a significant correlation between right heart echocardiographic parameters and concentrations of BNP in the plasma of young adults with ASD. BNP levels may provide a supplemental data to predict of shunt size in these patients.

Value of monitoring pulse oximetry for imputability of patent foramen ovale in transient dyspnoea.

Diagnosis of patent foramen ovale (PFO) is commonly made by echocardiography with contrast injection. PFO can be responsible for a transient right-to-left shunting with paroxysmal dyspnoea but punctual measurements of oxygen saturation may fail to detect arterial desaturations. Thus, claiming the imputability of PFO in dyspnoeic symptoms remains difficult. We report on the case of a 64-year-old man presenting an intermittent disabilitating dyspnoea, for which the pulse oximetry monitoring allowed to impute symptoms to the right-to-left shunting through the PFO and influenced the decision of percutaneous closure.

Restrictive left atrial outflow adversely affects outcome after the modified Norwood procedure.

OBJECTIVE: Moderate restrictive foramen ovale in neonates with hypoplastic left heart syndrome (HLHS) is considered to be favourable, reducing pulmonary overcirculation, before modified Norwood operation. However, some newborns with severe restriction of interatrial communication will have pulmonary vascular disease at birth, which correlates with increased perioperative mortality. This article studies the post-Norwood hemodynamic patterns and outcome for the particular group of HLHS newborns with restrictive left atrial outflow compared to other patients. METHODS: Restrictive left atrial outflow is defined as mitral and/or aortic atresia with intact ventricular septum, and restrictive foramen ovale, with 3 mm diameter or less with mean interatrial pressure gradient more than 5 mmHg at preoperative echo-Doppler. Four neonates fulfilled these criteriae among 18 consecutive patients, who underwent Norwood procedure from October 2002 to December 2003. Mean arterial pressure, heart rate, mean common atrial pressure, urinary output, central venous and arterial oximetry data, serum lactate levels, and dosages of milrinone, phentolamine and norepinephrine were collected at 0, 6, 12, 18 and 24 h after operation. Data were summarized as mean+/-SEM. For univariate comparison of different variables, Student's t-test was used. RESULTS: The postoperative hemodynamic pattern of patients with restrictive left atrial outflow was characterized by hypoxemia and low cardiac output. Arterial (66+/-3.0% vs 76+/-1.0%, P=0.01) and central venous (37+/-1.2 vs 52+/-1.1%, P=0.001) oxygen saturations were much lower than in patients without restriction. Arterio-venous oxygen saturation difference was wider (29+/-2.4% vs 23+/-0.9%, P=0.02) and serum lactate levels were higher (10.8+/-3.0 vs 2.8+/-0.2 mmol/l, P=0.03). Common atrial pressures were more elevated (12+/-0.8 vs 8+/-0.3 mmHg, P<0.001) and higher norepinephrine doses were needed (0.44+/-0.15 vs 0.06+/-0.01 microg/kg/min, P=0.03). The difference for the mean arterial pressures did not reach the significance level (48+/-2.0 vs 51+/-2.0 mmHg, P=0.2). Operative mortality was higher 75% (3/4) compared to 14.3% (2/14, P=0.04) for the other patients. CONCLUSIONS: Restrictive left atrial outflow adversely affects outcome after modified Norwood procedure. Abnormal pulmonary vasculature leading to insufficient pulmonary perfusion is incriminated. To improve outcome, implantation of larger size modified Blalock-Taussig or right ventricle-to-pulmonary artery shunts and routine use of postoperative mechanical assist device should be considered.

Dextran sulfate as a leukocyte-endothelium adhesion molecule inhibitor of lung injury in pediatric open-heart surgery.

BACKGROUND: In spite of the progress in operative techniques and pre- and postoperative management for congenital heart disease, lung injury induced by the extracorporeal circulation is still a serious insult in pediatric open-heart operations. To prevent this injury, we used a leukocyte-endothelial cell adhesion molecule blocking agent, dextran sulfate, in a clinical setting. METHODS: Sixty mg/kg of dextran sulfate (DS) was intravenously infused to the patients just before cardiopulmonary bypass was started and 600 mg was added to the bypass circuit prime. Thirty patients (DS group, 14 patients with atrial septal defect, and 16 patients with ventricular septal defect) were compared with age and body-weight matched control patients (control group, 14 patients with atrial septal defect, 11 patients with ventricular septal defect). Postoperative respiratory index, white blood cell counts, complement C3 and plasma granulocyte elastase levels during and after the operation were measured. RESULTS: Respiratory index just after the termination of cardiopulmonary bypass was better preserved in the DS group than in the control group (0.50 +/- 0.08 versus 0.81 +/- 0.12, p < 0.01). The sum total amount of measured granulocyte elastase across whole study period was significantly lower in the DS group (p < 0.05). CONCLUSIONS: The data suggeste the possible effects of dextran sulfate in ameliorating post-perfusion lung damage by interfering with leukocyte-endothelial cell adhesion in pediatric open-heart operations. Future application to patients with more complex anomalies is anticipated.

Menstrual cycle dependent right-to-left shunting: a single-blinded transcranial Doppler sonography study.

BACKGROUND AND PURPOSE: Menstruation has been described as risk factor for neurological decompression sickness in divers. In considering this for paradoxical gas embolism, we hypothesized that there may be a link between cycle-dependent hormonal changes and the manifestation of a right-to-left shunt (RLS). METHODS: 40 women with a regular cycle of 28 days underwent transcranial Doppler sonography examinations (TCD) on day 1 and on day 15 of the menstrual cycle. Cerebral high intensity transient signs (HITS) proved a RLS. RESULTS: We found a 25% RLS incidence consistent with the literature. In 7 of 10 shunt-positive women it was detected mainly or exclusively on day 15. This difference in PFO detection rate is statistically significant (p = 0.031), indicating more RLS during the peri-ovulatory period. CONCLUSIONS: Our results do not support menstruation as a risk factor for neurological decompression sickness. The peri-ovulatory estrogen peak, which leads to systemic vasodilation, may explain our data. Factors that increase the risk for developing a RLS and thereby paradoxical embolism should be avoided, perhaps including diving during the peri-ovulatory period of the menstrual cycle. Furthermore, contrast PFO testing in fertile females may be most sensitive if conducted mid-cycle.

Elevation of the tumor marker CA125 in right heart failure.

Carbohydrate antigen 125, known as a marker for ovarian cancer, has been reported to be elevated in heart failure caused by left ventricular dysfunction. A case of elevated carbohydrate antigen 125 in isolated right heart failure due to atrial septal defect with preserved left ventricular function is reported.

Atrial natriuretic peptide levels in adult patients before and after surgery for correction of atrial septal defects: relationship with atrial arrhythmias.

In the present study, we have examined whether increased N-ANP (N-terminal pro-ANP) levels before and after surgery in patients with ASD (atrial septal defect) along with echocardiographic findings provide a better insight into the pathophysiology and increased morbidity and mortality following corrective surgery. Eighteen adult ASD patients (> 20 years of age; six male and 12 female) with shunts (Qp/Qs > or = 2, where Qp/Qs is the pulmonary blood flow/systemic blood flow) had complete echocardiographic, clinical and laboratory parameters evaluated before and 6 months after surgery. Eight age- and sex-matched individuals (three male and five female) were enrolled as a control group. Blood samples for N-ANP analysis were obtained in both groups. N-ANP levels in the peripheral blood sample from ASD patients before surgery were significantly higher than those in the control group. In patients with ASD, mean N-ANP levels obtained from the pulmonary artery were significantly higher than that obtained from the peripheral vein. RA (right atrial) area, adjusted for body surface area, and RA long-axis and short-axis measurements were significantly higher in the patient group than the control group. N-ANP was correlated significantly with these parameters. Following corrective surgery, N-ANP values and RA area, RA long-axis and short-axis normalization decreased significantly and were accompanied by a decrease in systolic mean pulmonary artery pressure. N-ANP levels were normalized following septal closure in most patients, except in those with atrial fibrillation attacks following corrective surgery. In conclusion, we have shown correlations among variables indicating changes in the architecture of the right atrium along with temporal changes in ANP providing insights into the pathophysiology of post-operative atrial arrhythmias.

Natriuretic peptide and echocardiography after operation of atrial septal defect.

Patients benefit from surgical seclusion of atrial septal defect but have excessive cardiovascular morbidity after the operation. We evaluated haemodynamics and looked for abnormalities of cardiac structures and function late after surgical seclusion of the defect. Serum N-terminal natriuretic peptide measurement and transthoracic and transoesophageal echocardiography were performed in 61 patients aged 43+/-15 years (mean+/-standard deviation) 21+/-5 years after surgery. The findings were compared with 67 control subjects. The patients had higher serum N-terminal atrial natriuretic peptide concentration than the control subjects (0.40+/-0.32 vs. 0.24+/-0.12 nmol/l, P=0.0001). Peptide levels correlated with current age (P=0.0001) and age at operation (P=0.0014), but not with age in the control subjects. In the patients, echocardiography measurements of cardiac dimensions correlated with hormone levels (atrial natriuretic peptide concentration with left atrial end-systolic diameter (P=0.042), left ventricular end-diastolic (P=0.021) and end-systolic diameter (P=0.042). There were only 10 patients (16%) without any abnormality in echocardiography. Their peptide concentration was 0.25+/-0.18 nmol/l (P=not significant compared to the control subjects). The association between increasing N-terminal atrial peptide levels and operation age together with echocardiography findings support the clinical consensus of treating atrial septal defect patients in their childhood and adolescence.

Soluble endothelial adhesion molecules during paediatric cardiovascular surgery with or without cardiopulmonary bypass.

BACKGROUND: Paediatric cardiovascular surgery with or without cardiopulmonary bypass induces a complex pattern of pro- and anti-inflammatory responses. It is suspected that they may contribute to changes on the vascular endothelium. The endothelial response to cardiosurgical trauma and cardiopulmonary bypass, especially in children, has yet to be well established. PATIENTS AND METHODS: We studied 29 children undergoing cardiovascular surgery with cardiopulmonary bypass, comparing them with 21 not undergoing bypass. The groups did not differ significantly with respect to age, sex, weight and preoperative parameters. Blood samples were drawn 24 h before surgery, after onset of anaesthesia, after onset of cardiopulmonary bypass and after rewarming in those undergoing bypass, or immediately after surgery in the control group, 4 h and 2 days after surgery, at discharge, and months after surgery during out-patient follow-up. Serum levels of soluble E-selectin, P-selectin and P-selectin glycoprotein ligand-1 were measured by enzyme-linked immunoassay. RESULTS: Paediatric cardiovascular surgery leads perioperatively to the significant decreases of the serum levels of soluble P- and E-selectin, as well as of soluble P-selectin glycoprotein ligand-1 (all p < 0.05). The time course, and all concentrations, of these molecules were not significantly different with and without bypass. The decreases, however, were more pronounced with cardiopulmonary bypass. Preoperative baseline values were reached months after surgery. CONCLUSION: Endothelial activation of release of adhesion molecules is reduced during paediatric cardiovascular surgery. Endothelial activity is more perturbed with cardiopulmonary bypass and for a long time after surgery.

Lung impairment following cardiac surgery in patients with pulmonary hypertension.

BACKGROUND: Postoperative respiratory management following cardiac surgery is sometimes troublesome in patients with pulmonary hypertension. We retrospectively studied the relationship between the etiology of preoperative pulmonary hypertension and the postoperative decline of blood oxygenation capacity by focusing on the postoperative intravascular fluid volume. METHODS: Sixteen adult patients with an atrial septal defect (preload group) and 17 patients with solitary mitral valve disease (afterload group) were studied. The mean age of the patients in the preload and afterload group was 51 and 52 years old, respectively. RESULTS: Preoperative pulmonary-systemic pressure ratio and pulmonary artery resistance index were significantly higher in the preload group than in the afterload group. The respiratory index (RI) and the pulmonary shunt ratio (Qs/Qt) measured immediately after the operation was larger in the afterload group than in the preload group. Postoperative RI and Qs/Qt remained high until postoperative day 3 in both groups. In the preload group RI on postoperative day 1 had a reverse correlation with the central venous pressure (CVP). Meanwhile, the RI in the afterload group on postoperative day 1 was slightly larger in patients with a high CVP and pulmonary capillary wedged pressure. Similar relationships were seen in the relations between pulmonary capillary wedged pressure and RI in the afterload group. CONCLUSIONS In conclusion, a preoperative pulmonary vascular change and a postoperative precipitous decrease of pulmonary blood flow may have caused postoperative lung oxygenation impairment in the preload group. An extended period of extracorporeal circulation associated with cardiac arrest and postoperative volume overload may have caused lung impairment in the afterload group. In aspect of postoperative management, low CVP is beneficial to the patients in the afterload group, however, hypovolemia should be avoided in patients of the preload group.

Transcutaneous-PO2 monitoring for detection of exercise-induced right-to-left shunts in children with congenital heart defects: a case report.

UNLABELLED: A 2-y-old boy with scimitar syndrome underwent surgery involving the redirection of partial anomalous pulmonary venous return to the left atrium. Heart catheterization after the operation did not reveal any significant intra-cardiac shunts. An exercise test performed at the age of 10 y revealed a reduction in working capacity. At the age of 12 y, the patient became unconscious and experienced seizures during heavy physical exercise. EEG and Holter ECG examinations were normal. In a second exercise test, a fall in transcutaneous PO2 was demonstrated at the start of the test. A new heart catheterization revealed communication between the inferior vena cava and the left atrium owing to a misplaced patch. No right-to-left shunt was found at rest, probably as a result of drainage of the inferior vena cava to the superior vena cava by the azygous vein. An exercise test after re-operation revealed normal conditions. CONCLUSION: Haemodynamic studies during heart catheterization in children are usually performed at rest. This could result in exercise-induced right-to-left-shunts being overlooked. The use of PtcO2 monitoring during exercise tests is a non-invasive means of exposing these shunts.

Arterial desaturation and orthodeoxia after atrial septal defect repair: demonstration of the mechanism by transesophageal and contrast echocardiography.

A young woman without symptoms underwent repair of an ostium secundum atrial septal defect, and exertional dyspnea developed postoperatively. This was found to be due to arterial oxygen desaturation which was exaggerated in the upright position and with exercise. Contrast echocardiography confirmed a right-to-left shunt at the atrial level that was shown only with femoral venous contrast injection and not with upper extremity venous injection. Transesophageal echocardiography and subsequent surgical exploration found that the Eustachian valve had been mistaken for the inferior rim of the defect and sutured to the upper rim of the defect. This created a channel through which blood from the inferior vena cava could be partially deferred to the left atrium.