Systemic Arterial Oxygen Saturation Research Articles

Short apneas and periodic breathing in preterm infants in the neonatal intensive care unit-Effects of sleep position, sleep state, and age.

This observational study investigated the effects of sleep position and sleep state on short apneas and periodic breathing in hospitalized preterm infants longitudinally, in relation to postmenstrual age. Preterm infants (25-31 weeks gestation, n = 29) were studied fortnightly after birth until discharge, in prone and supine positions, and in quiet sleep and active sleep. The percentage of time spent in each sleep state (percentage of time in quiet sleep and percentage of time in active sleep), percentage of total sleep time spent in short apneas and periodic breathing, respectively, the percentage of falls from baseline in heart rate, arterial oxygen saturation and cerebral tissue oxygenation index during short apneas and periodic breathing, and the associated percentage of total sleep time with systemic (arterial oxygen saturation < 90%) and cerebral hypoxia (cerebral tissue oxygenation index < 55%) were analysed using a linear mixed model. Results showed that the prone position decreased (improved) the percentage of falls from baseline in arterial oxygen saturation during both short apneas and periodic breathing, decreased the proportion of infants with periodic breathing and the periodic breathing-associated percentage of total sleep time with cerebral hypoxia. The percentage of time in quiet sleep was higher in the prone position. Quiet sleep decreased the percentage of total sleep time spent in short apneas, the short apneas-associated percentage of falls from baseline in heart rate, arterial oxygen saturation, and proportion of infants with systemic hypoxia. Quiet sleep also decreased the proportion of infants with periodic breathing and percentage of total sleep time with cerebral hypoxia. The effects of sleep position and sleep state were not related to postmenstrual age. In summary, when sleep state is controlled for, the prone sleeping position has some benefits during both short apneas and periodic breathing. Quiet sleep improves cardiorespiratory stability and is increased in the prone position at the expense of active sleep, which is critical for brain maturation. This evidence should be considered in positioning preterm infants.

Anesthesia in A Patient with Pulmonary Atresia with Intact Ventricular Septum (PA IVS) Underwent Bidirectional Cavo-Pulmonary Shunt (BCPS)

Background: Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare condition, encompassing approximately 1%–3% of congenital heart diseases. Patients with PA-IVS have functional single-ventricle physiology. The ultimate possible outcomes for patients with PA-IVS are biventricular circulation, 1.5-ventricle or single-ventricle palliation, or cardiac transplantation. The bidirectional cavopulmonary shunt (BCPS) procedure directs flow from the superior vena cava into both the right and left pulmonary arteries, permitting flow to both lungs. The shunt is considered to be the second stage of palliation and is generally preparative for the third-stage Fontan procedure. The BCPS improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance.Case: A 10-month-old, 25-day-old boy, weight 9.93 kg, body length 72 cm, diagnosed with PA-IVS, restricted persistent foramen ovale (PFO), right ventricle hypoplastic, and turtuous patent ductus arteriosus (PDA), underwent BCPS, atrial septectomy, and PDA stent evacuation surgery. The patient underwent a PDA stenting and ballooning atrial septectomy (BAS) at 17 days of age at the cathlab. The patient was cyanotic with stable hemodynamics and a saturation of 72% preoperatively.Discussion: Preoperative fasting must be observed to maintain the patient's hydration state. Pulmonary blood flow and systemic blood flow must be balanced. An adequate analgetic can prevent pain stimuli that increase pulmonary vascular resistance. Drugs to reduce the afterload, such as milrinone, are needed. Mechanical ventilation was set to get PaCO2 between 40 and 45 mmHg. Maintain the normal heart beat, preload, and contractility to maintain cardiac output (CO) with saturation 80–85%. Wean from mechanical ventilation as soon as possible.Conclusion: Anesthetic management for BCPS in patients with single ventricles from the preoperative period, intraoperative period, and postoperative period. Understanding single ventricle phsiology is important in order to treat the patient.

Acute Hemodynamics in the Fontan Circulation: Open-Label Study of Vasopressin.

To describe the acute hemodynamic effect of vasopressin on the Fontan circulation, including systemic and pulmonary pressures and resistances, left atrial pressure, and cardiac index. Prospective, open-label, nonrandomized study (NCT04463394). Cardiac catheterization laboratory at Lucile Packard Children's Hospital, Stanford. Patients 3-50 years old with a Fontan circulation who were referred to the cardiac catheterization laboratory for hemodynamic assessment and/or intervention. A 0.03 U/kg IV (maximum dose 1 unit) bolus of vasopressin was administered over 5 minutes, followed by a maintenance infusion of 0.3 mU/kg/min (maximum dose 0.03 U/min). Comprehensive cardiac catheterization measurements before and after vasopressin administration. Measurements included pulmonary artery, atrial, and systemic arterial pressures, oxygen saturations, and systemic and pulmonary flows and resistances. There were 28 patients studied. Median age was 13.5 (9.1, 17) years, and 16 (57%) patients had a single or dominant right ventricle. Following vasopressin administration, systolic blood pressure and systemic vascular resistance (SVR) increased by 17.5 (13.0, 22.8) mm Hg ( Z value -4.6, p < 0.001) and 3.8 (1.8, 7.5) Wood Units ( Z value -4.6, p < 0.001), respectively. The pulmonary vascular resistance (PVR) decreased by 0.4 ± 0.4 WU ( t statistic 6.2, p < 0.001), and the left atrial pressure increased by 1.0 (0.0, 2.0) mm Hg ( Z value -3.5, p < 0.001). The PVR:SVR decreased by 0.04 ± 0.03 ( t statistic 8.1, p < 0.001). Neither the pulmonary artery pressure (median difference 0.0 [-1.0, 1.0], Z value -0.4, p = 0.69) nor cardiac index (0.1 ± 0.3, t statistic -1.4, p = 0.18) changed significantly. There were no adverse events. In Fontan patients undergoing cardiac catheterization, vasopressin administration resulted in a significant increase in systolic blood pressure, SVR, and left atrial pressure, decrease in PVR, and no change in cardiac index or pulmonary artery pressure. These findings suggest that in Fontan patients vasopressin may be an option for treating systemic hypotension during sedation or general anesthesia.

Clinical and invasively-measured predictors of high exercise capacity in Fontan patients

IntroductionFontan patients have variable exercise capacity. Contemporary understanding as to which factors predict high tolerance is limited. MethodsRecords from the Ahmanson/University of California, Los Angeles Adult Congenital Heart Disease Center were reviewed for adult Fontan patients who underwent CPET. Patients were considered “high performers” if their maximum oxygen uptake (VO2 max/kg)-predicted was greater than 80%. Cross-sectional clinical, hemodynamic, and liver biopsy data was gathered. High-performers were compared to control patients across these parameters via associations and regression. ResultsA total of 195 adult patients were included; 27 patients were considered “high performers”. They had lower body mass indices (BMI, p < 0.001), mean Fontan pressures (p = 0.026), and cardiac outputs (p = 0.013). High performers also had higher activity levels (p < 0.001), serum albumin levels (p = 0.003), non-invasive and invasive systemic arterial oxygen saturations (p < 0.001 and p = 0.004), lower New York Heart Association (NYHA) heart failure class (p = 0.002), and were younger at Fontan completion (p = 0.011). High performers had less severe liver fibrosis (p = 0.015). Simple regression found Fontan pressure, non-invasive O2 saturation, albumin level, activity level, age at Fontan surgery, NYHA class, and BMI to predict significant changes in VO2 max/kg %-predicted. These associations persisted in multiple regression for non-invasive O2 saturation, NYHA class II, activity level, and BMI. ConclusionsThin Fontan patients who exercise more had better exercise capacity, Fontan hemodynamic profiles, and less liver fibrosis.

RETROSPECTIVE STUDY OF GLENN SHUNT WITHOUT CARDIOPULMONARY BYPASS

The bidirectional Glenn shunt improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance (1).BDG is a commonly performed procedure for a variety of cyanotic congenital heart diseases that lead eventually to a single ventricle repair (2).It is an important intermediate palliation in patients with a structurally or functionally univentricular heart who are ultimately destined to have a Fontan-type operation (3). Avoidance of cardiopulmonary bypass (CPB) has the advantage of early extubation, less blood products, reduced requirement and duration of inotropic support (4).The end-to-side anastomosis of the superior vena cava (SVC) to the right or left pulmonary artery, which may be converted to a total cavopulmonary connection later, can effectively both increase arterial blood oxygen saturation of the patients and decrease volume overload of the ventricle (5)

Sildenafil for adult Asian patients with pulmonary arterial hypertension: a systematic review and meta-analysis.

The prognosis of patients with untreated pulmonary arterial hypertension (PAH) has historically been poor. Previous studies have recommended that sildenafil was beneficial, but the dose varies greatly. In this study, we aimed to evaluate the safety and effectiveness of sildenafil [dose: 20 mg/three times a day (TID)] for adult Asian PAH patients. Electronic databases (MEDLINE, Embase, Web of Science, the Cochrane Library, CBM, CNKI, and Wanfang Data) were searched from their inception to January 2022. We recruited all randomized controlled trials and non-randomized studies of interventions that compared sildenafil (20 mg/TID) versus placebo or symptomatic treatment for adult Asian PAH patients. A total of 10 studies involving 480 participants were included. Compared to symptomatic treatment, sildenafil-treated patients were more likely to walk 57.68 meters further in six-minute walk distance [mean difference (MD) =57.68 m, 95% confidence interval (CI): 41.55 to 73.81], achieve an improvement in systemic arterial oxygen saturation (MD =2.48%, 95% CI: 1.26 to 3.71), and increase the score of the Borg scale for dyspnea (MD =-0.99 points, 95% CI: -1.45 to -0.53). The total number of patients with World Health Organization class III and IV also exhibited a downtrend. Compared to the placebo, sildenafil was associated with a reduction in the mean pulmonary artery pressure (MD =-4.13 mmHg, 95% CI: -6.52 to -1.74) and the level of brain natriuretic peptide (MD =-86.16 pg/mL, 95% CI: -103.39 to -68.93). The most common adverse events were headache, flushing, dyspepsia, and diarrhea, which were relatively mild. Sildenafil at a dose of 20 mg/TID is well tolerated in adult Asian PAH patients, and is associated with statistically significant improvements in exercise capacity, cardio-pulmonary function, and haemodynamic indices. The long-term prognosis still needs to be evaluated and confirmed by further trials.

The physiology of extracorporeal membrane oxygenation: The Fick principle.

Extracorporeal membrane oxygenation (ECMO) can be delivered in veno-arterial (VA) and veno-venous (VV) configurations based on the cannulation strategy. VA and VV ECMO are delivered primarily for haemodynamic and respiratory support in patients with severe heart and lung failure, respectively. The Fick principle describes the relationship between blood flow and oxygen consumption - key parameters in the physiological management of extracorporeal support. This review will discuss the application of the Fick principle in: (i) recirculation in VV ECMO; (ii) the quantification of oxygen delivery (DO2) in VV ECMO and (iii) the quantification of transpulmonary blood flow and systemic arterial oxygen saturation in VA ECMO.

The Critical Role of Pulmonary Artery Wedge Pressure Saturation In The Standardization of Pulmonary Artery Wedge Pressure Measurement

Introduction Inadequate balloon occlusion while measuring pulmonary artery wedge pressure (PAWP) during right heart catheterization (RHC) may lead to inaccurate measures and clinically relevant misdiagnosis of disease. Following the 6th World Symposium on Pulmonary Hypertension (PH) recommendations, we instituted a standard of care clinical protocol at the Medical University of South Carolina that required obtaining a PAWP saturation (sat) to confirm complete occlusion whenever initially measured PAWP is >15 mmHg. We sought to determine: 1) The difference between initial and lowest reported PAWP 2) The frequency in which this practice leads to a change in PH classification 3) The overall success rate in obtaining a PAWP sat. Methods After IRB approval, investigators not performing the RHC procedure prospectively collected demographic, echocardiographic and hemodynamic data. Subjects undergoing routine post-transplant RHC were excluded. After the initial PAWP measurement (as determined by the RHC operator), a PAWP sat was drawn to confirm occlusion (defined as >90% or within 5% of the systemic arterial oxygen saturation). If the PAWP sat did not confirm occlusion, the balloon was deflated and up to two additional attempts were made to re-measure the PAWP and confirm with a PAWP sat. PAWP were recorded at the same point in the respiratory cycle with each attempt. Repeated measures were compared using Signed Rank Test. Results We enrolled 75 subjects (age 58.3 +/- 13.3 years, 60% men, 59% with LVEF 15 mmHg. Despite apparent confirmation of PAWP position by fluoroscopy and/or typical hemodynamic waveforms, an occlusive PAWP sat was unable to be confirmed in 39 (52%) of subjects during the first attempt. In these subjects, the mean difference between initial and lowest PAWP was -4.1 +/- 7.7 mmHg (p 5 mmHg. Three of the 4 subjects referred for PH with preserved EF were ultimately reclassified as having pre-capillary PH. Eight of the 16 referred for advanced heart failure evaluation were re-classified as combined post- and pre-capillary PH with PVR > 3 WU, which then required vasodilator testing. With additional attempts, a PAWP sat was confirmed in 83% of subjects. There were no observed complications during additional PAWP attempts. Conclusion The practice of requiring a PAWP sat resulted in significantly lower PAWP, higher PVR and clinically relevant disease reclassification. A PAWP sat is a simple and safe technique to verify an elevated PAWP during RHC.

Hemodynamic Effects of Additional Pulmonary Blood Flow on Glenn and Fontan Circulation.

Additional pulmonary blood flow (APBF) can provide better pulsating blood flow and systemic arterial oxygen saturation, while low blood pulsation and low oxygen saturation are defects of the Fontan and Glenn procedure. Studying the hemodynamic effect of APBF is beneficial for clinical decisions. This study aimed to explore the effect on particle washout, as well as the differences among the sensitivities of both different hemodynamic parameters and different procedures to APBF. The patient-specific clinical datasets of a patient who underwent bilateral bidirectional Glenn (BBDG) with APBF were enrolled in this study, and using these datasets, Glenn- and Fontan-type artery models were reconstructed. A series of parameters, including the total caval flow pulsatility index (TCPI), indexed energy loss (iPL), wall shear stress (WSS), systemic arterial oxygen saturation (Satart), particle washout time (WOT), pressure in the rightsuperior vena cava (PRSVC), pulmonary flow distribution (PFD) and hepatic flow distribution (HFD), were computed from computational fluid dynamic (CFD) simulation to evaluate the hemodynamic effect of APBF. The result showed that APBF led to better iPL and Satart but worse PRSVC and heart load accompanied by a great impact on HFD, making hepatic flow easier to perfuse the side without MPA and APBF. The increase in the APBF rate also effectively results in larger flow pulsation, region velocity, and wall shear stress and lower WOT, and this effect may be more effective for patients with persistent left superior vena cava (PLSVC). However, APBF might have little effect on PFD. Furthermore, APBF might affect WOT, iPL and HFD more significantly than PRSVC and has a greater improvement effect in patients with poorer iPL and WOT. Moderate APBF is not only a measure to promote pulmonary artery growth and systemic arterial oxygen saturation but also an effective method against endothelial dysfunction and thrombosis. However, moderate APBF is patient-specific and should be determined based on hemodynamic preference that leads to desired patient outcomes, and care should be taken to prevent PRSVC and heart load from being too high as well as an imbalance in HFD.

Results of surgery on adults with functional single ventricle without prior cardiac surgery in childhood.

Patients with unoperated functional single ventricle (FSV) rarely survive into adulthood with good functional status and there are few reports about surgical results of adult patients with FSV. This study retrospectively reviews our experience with surgery in adult patients with FSV. From January 2008 to September 2017, 65 adult patients with FSV underwent surgery in our hospital. Twenty underwent Blalock-Taussig shunt or bidirectional Glenn procedures in other hospitals prior, and four were lost to follow-up. Finally, 41 patients were included in this study. The early postoperative mortality was 7.3% (3/41). Postoperative systemic arterial oxygen saturation (SpO2 , 83.7% ± 4.8%) was significantly higher than preoperative SpO2 (77.9% ± 10.1%, P < .01). The mean follow-up time was 3.9 ± 3.1 years (range 1-11 years). There was only one case of late mortality and massive hemoptysis was the cause of death. Right ventricular morphology and severe atrioventricular valve regurgitation (AVVR) were the risk factors of postoperative death for patients with pulmonary stenosis(PS). There was no death case in patients who received Fontan procedure. In a follow-up, we found the grade of AVVR was reduced and the grade of heart function (New York Heart Association) was improved. Adult patients with FSV can also undergo surgery. The mortality was acceptable and late results were satisfactory. After surgery, oxygen saturations increased, grades of AVVR decreased and the heart functions improved. Right ventricular morphology and severe AVVR were risk factors for patients with PS.

4284The combined use of radiofrequency-ablation and balloon-dilation (CURB) in the creation of a stable inter-atrial communication: first-in-man use for patients with severe pulmonary arterial hypertension

Abstract Background Recent preclinical research has suggested that combined use of radiofrequency-ablation and balloon-dilation (CURB) had the potential to create a stable inter-atrial communication. However, the related clinical data is still absent. Purpose This study describes the first-in-man use of CURB in the patients with severe pulmonary arterial hypertension (PAH). Methods Under the guidance of fluoroscopy and intra-cardiac echocardiography, CURB was attempted in 3 patients with severe PAH (age: 35.0±12.1 years, one idiopathic PAH and two PAH related to repaired congenital heart disease). With the aid of 3D location system, fossae ovalis was ablated with radiofrequency. Then the graded balloon-dilation was performed after transseptal puncture, and radiofrequency-ablation was repeated around the rim of fenestration created with balloon-dilation. The exercise capacity and fenestration-size were followed up. Results CURB was performed successfully in all 3 patients, and pulmonary vascular resistance was 30.3±10.9 Wood units. The fenestration size was 5.0±1.0 mm (range: 4–6 mm), and systemic arterial oxygen saturation decreased by 4.7±0.6% (range: 4–5%). World Health Organization functional class increased by 1.6±0.5 (P&lt;0.001) and cardiac index increased by 0.58±0.34 L/min/m2 (P&lt;0.001). In addition, exercise capacity improved significantly (+63.7 meters, P&lt;0.001). Follow-up (6.0±1.0 months; range: 5–7 months) showed that all fenestrations were stable (P=0.808), and no complication occurred. Figure 1. The combined use of radiofrequency-ablation and balloon-dilation (CURB) was performed in the patient with severe PAH. Left figures showed the procedure of CURB. Middle figures showed the created fenestration with MSCT, and the morphology and size of fenestration was provided in the right-inferior panel. In addition, the sizes of right atrium and ventricle were alleviated with increase of left atrium. Right figures indicated that the fenestration-size was stable during follow-up (one week, one month and six months, respectively). Conclusions In patients with severe PAH, CURB is feasible and effective to create a stable inter-atrial communication. Further research was required to evaluate the long-term result of this novel approach. ClinicalTrials.gov ID: NCT03554330. Acknowledgement/Funding National Natural Science Foundation of China (81670283) and Beijing Natural Science Foundation (7162160)

Long-term results after palliative intra-cardiac repair for tetralogy of Fallot and diminutive pulmonary arteries.

In patients with tetralogy of Fallot with the diminutive pulmonary arteries, we sometimes have to give up the complete intra-cardiac repair due to insufficient growth of the pulmonary arteries. We have carried out palliative intra-cardiac repair using a fenestrated patch. Of all 202 patients with tetralogy of Fallot in our centre since 1996, five patients (2.5%) with the diminutive pulmonary arteries underwent palliative intra-cardiac repair using a fenestrated patch. Mean operative age was 1.8 years. Previous operation was Blalock-Taussig shunt in 4. At operation, the ventricular septal defect was closed using a fenestrated patch and the right ventricular outflow tract was enlarged. Follow-up period was 9.8 ± 2.6 years. There were no operative and late deaths. Fenestration closed spontaneously on its own in four patients 2.7 ± 2.1 years after the intra-cardiac repair with a stable haemodynamics; however, the last patient with the smallest pulmonary artery index had supra-systemic pressure of the right ventricle post-operatively. The fenestration was emergently enlarged. Systemic arterial oxygen saturation was significantly and dramatically increased from 83.5 to 94% after the palliative intra-cardiac repair, and to 98% at the long term. A ratio of systolic pressure of the right ventricle to the left was significantly decreased to 0.76 ± 0.12 at the long term. Now all five patients were Ross classification class I. Although frequent catheter and surgical interventions were needed after the palliative intra-cardiac repair, this repair might be a choice improving quality of life with good results in patients with tetralogy of Fallot associated with the diminutive pulmonary arteries.

Pulmonary hypertensive crisis in children with idiopathic pulmonary arterial hypertension undergoing cardiac catheterization: the risk factors and clinical aspects

Objective: To investigate the risk factors, clinical features, treatments, and prevention of pulmonary hypertensive crisis (PHC) in children with idiopathic pulmonary arterial hypertension (IPAH) undergoing cardiac catheterization. Methods: This retrospective study included 67 children who were diagnosed with IPAH and underwent cardiac catheterization between April 2009 and June 2017 in Beijing Anzhen Hospital. The medical histories, clinical manifestations, treatments, and outcomes were characterized. Statistical analyses were performed using t test, χ(2) test and a multiple Logistic regression analysis. Results: During cardiac catheterization, five children developed PHC who presented with markedly elevated pulmonary artery pressure and central venous pressure, decline in systemic arterial pressure and oxygen saturation. Heart rate decreased in 4 cases and increased in the remaining one. After the treatments including cardiopulmonary resuscitation, pulmonary vasodilator therapy, improving cardiac output and blood pressure, and correction of acidosis, 4 of the 5 cases recovered, while 1 died of severe right heart failure with irreversible PHC 3 days after operation. Potential PHC was considered in 7 other patients, whose pulmonary artery pressure increased and exceeded systemic arterial pressure, oxygen saturation decreased, and central venous pressure and vital signs were relatively stable. Univariate analysis showed that the risk factors of PHC in children with IPAH undergoing cardiac catheterization were younger age (t=3.160, P=0.004), low weight (t=4.004, P<0.001), general anesthesia (χ(2)=4.970, P=0.026), history of syncope (χ(2)=4.948, P=0.026), and WHO cardiac functional class Ⅲ or Ⅳ (χ(2)=19.013, P<0.001). Multivariate Logistic regression analysis revealed that worse WHO cardiac functional class (Wald=13.128, P<0.001, OR=15.076, 95% CI: 3.475-65.418) was the independent risk factor of PHC. Conclusions: PHC is a severe and extremely dangerous complication in children with IPAH during cardiac catheterization. WHO cardiac functional class may be associated with PHC. Integrated treatment is required for these patients. Reducing risk factors, early identification, and active treatment may help to prevent the occurrence and progression of PHC.

Hemodynamic determinants of mortality after Fontan operation

Elevated central venous pressure (CVP), low cardiac output, and mild hypoxia are common early and late after Fontan operations. However, the association of these characteristics with late mortality is unclear. We aimed to elucidate the hemodynamic determinants of mortality after Fontan operation. We evaluated early (group early; 0.5-5years postoperatively, n=387) and late (group late; ≥15years postoperatively, n=161) Fontan hemodynamics that included CVP (mm Hg), cardiac index (CI; L/min per m2), systemic ventricular end-diastolic volume index (mL/m2), ejection fraction (EF; %), and arterial blood oxygen saturation (%). We examined the effect of these variables on 5-year all-cause mortality. Mortality was higher in group late than in group early (17 vs 11, P<.0001). In both groups, higher CVP (hazard ratio [HR]1.46 and 1.38, respectively; P<.001-.0001) and lower arterial blood oxygen saturation (HR 1.12, P<.001 for both) were associated with increased mortality. Greater end-diastolic volume index (HR per 20: 1.73) and lower EF (HR per 10%: 3.38) were associated with increased mortality only in group early (P<.0001 for both). In contrast, only in group late was higher CI associated with increased mortality (HR 2.50, 95% CI 1.30-4.55, P<.01). Seven patients in group late with both high CVP (≥14) and CI (≥3.0) had the highest mortality (HR 18.1, 5.55-52.4, P<.0001). Elevated CVP and low arterial blood oxygen saturation correlate with mortality in both early and late Fontan survivors. End-diastolic volume index and EF are associated with mortality only in the earlier cohort, whereas interestingly, elevated cardiac output is associated with increased mortality in the later cohort.

Monitoring Cerebral Oxygenation in Neonates: An Update.

Cerebral oxygenation is not always reflected by systemic arterial oxygenation. Therefore, regional cerebral oxygen saturation (rScO2) monitoring with near-infrared spectroscopy (NIRS) is of added value in neonatal intensive care. rScO2 represents oxygen supply to the brain, while cerebral fractional tissue oxygen extraction, which is the ratio between rScO2 and systemic arterial oxygen saturation, reflects cerebral oxygen utilization. The balance between oxygen supply and utilization provides insight in neonatal cerebral (patho-)physiology. This review highlights the potential and limitations of cerebral oxygenation monitoring with NIRS in the neonatal intensive care unit.

Patent ductus arteriosus with persistent pulmonary artery hypertension after transcatheter closure.

ObjectivesTo observe the change in pulmonary artery systolic pressure (PASP) of patients with persistent pulmonary arterial hypertension (PAH) after patent ductus arteriosus (PDA) occlusion.BackgroundAfter occlusion of PDA in patients with PAH, some patients still tend to suffer from persistent PAH.MethodsA chest X-ray, an electrocardiogram, and an echocardiogram were performed on nine patients at 24 hours, 1 and 6 months, and 1 year serially.ResultsThere was a significant fall (P<0.05) in mean PASP after occlusion (to 59.3±12.7 mmHg). However, the aortic pressure and systemic arterial oxygen saturation changed slightly (P>0.05). During the follow up, there was a further fall in the PASP in five patients (No 1, 5, 6, 7, and 8). Four patients (No 2, 3, 4, and 8) showed the evidence of worsening PAH and were treated with sildenafil. Patient 2 died from acute right heart failure after a period of 11 months from the time of transcatheter closure, triggered by pulmonary infection.ConclusionSome patients with borderline hemodynamic data with PDA and PAH can deteriorate or keep sustained PAH after PDA closure. The treatment of permanent closure to these patients must be cautious.

Effects of long-term iloprost treatment on right ventricular function in patients with Eisenmenger syndrome

BackgroundRight ventricular (RV) function is an important prognostic factor of pulmonary arterial hypertension (PAH), but there is insufficient data regarding RV function after long-term inhaled iloprost treatment. We evaluated the effect of long-term iloprost treatment on RV function in patients with Eisenmenger syndrome (ES). MethodsEleven consecutive patients with ES associated with congenital heart disease underwent echocardiographic measurements at baseline and 48 weeks after iloprost therapy. In addition, we recorded World Health Organization (WHO) functional class, 6-minute walk distance (6MWD), systemic arterial oxygen saturation (SaO2), and laboratory values such as hemoglobin, serum creatinine, and N-terminal pro-B natriuretic peptide. ResultsAfter 48 weeks of iloprost therapy, mean pulmonary arterial pressure (mPAP), pulmonary arterial systolic pressure (PASP), and pulmonary vascular resistance (PVR) were significantly decreased [mPAP, 42.5 (38.5–61.0) to 36.5 (29.1–40.0)mmHg; PASP, 92.6±19.9 to 74.5±23.8mmHg; PVR, 23.4 (19.8–26.0) to 23.4 (19.8–26.0)Wood unit respectively, all p<0.05]. There was also significant improvement in RV myocardial performance index [0.68 (0.61–0.80) to 0.52 (0.51–0.62), p=0.003] and RV longitudinal strain (−15.7±1.6 to −18.1±1.5%, p<0.001). In clinical assessment, WHO functional class (p=0.006), 6MWD (310.6±44.7 to 399.7±80.8m, p<0.001), and SaO2 (90.9±6.0% to 92.5±6.0%, p=0.022) were significantly improved. ConclusionThe improvement in echocardiographic parameters of the RV function after 48 weeks of iloprost therapy may provide insight on the efficacy of long-term iloprost treatment for RV functional improvement, which is a prognostic factor in patients with ES.

Guidelines for the management of grown-up congenital heart disease (new version 2010)

Nifedipine is a calcium antagonistic drug which reduces elevated vascular resistances. The hemodynamic effects of 20 mg of sublingual nifedipine were studied in 10 patients with chronic pulmonary hypertension. The etiology of pulmonary hypertension was chronic lung disease in 4, congenital heart disease in 2, mitral stenosis in 1, recurrent pulmonary embolism in 2 and primary pulmonary hypertension in one case. 30' after the drug administration there was a fall both of total pulmonary vascular resistance (from 992 +/- 586 to 648 +/- 428 d s cm-5, p less than 0.02) and of systemic vascular resistance (from 1416 +/- 868 to 896 +/- 440 d s cm-5 p less than 0.02) with an increase of systemic cardiac index from 3.2 +/- 1 to 4.5 +/- 2 l/min/m'2 (p less than 0.02). No significant change in systemic arterial oxygen saturation was noted, while pulmonary arterial oxygen saturation increased from 56 +/- 16 to 62 +/- 13% (p less than 0.01). These hemodynamic changes persisted for 120' when a significant fall of mean pulmonary arterial pressure was also noted (from 59 +/- 11 to 52 +/- 9 mm Hg, p less than 0.02). These data indicate that nifedipine may be useful to reduce pulmonary resistance in pulmonary hypertension. However this effect was less pronounced in patients with chronic lung disease compared to the other cases. It is suggested that the type of pulmonary arterial changes may determine the hemodynamic response. Nifedipine may be particularly indicated when vasoconstriction (as in primary pulmonary hypertension) is the main determinant of pulmonary hypertension.

Acute hemodynamic response of infused fasudil in patients with pulmonary arterial hypertension: A randomized, controlled, crossover study

BackgroundThe Rho-kinase pathway has been shown to be involved in the pathogenesis of PAH. As yet, however, the acute effects of the Rho-kinase inhibitor fasudil have not been compared with established pulmonary selective vasodilators in patients with PAH. We compared the acute effects of intravenous fasudil with inhaled iloprost in patients with pulmonary arterial hypertension (PAH). MethodsUsing a crossover design, 50 patients with PAH (idiopathic PAH, PAH associated with repaired left-to-right cardiac shunts, or connective tissue disease) were randomized to iloprost inhalation (5μg) and intravenous fasudil (30mg over 30min). Hemodynamic data were collected at baseline and during acute drug exposure. ResultsComparable decreases were observed in mean pulmonary artery pressure (−4.6±4.3mmHg vs. −4.8±4.2mmHg) and pulmonary vascular resistance (−3.0±3.0 Wood U vs. −2.2±2.7 Wood U) with fasudil infusion and iloprost inhalation, respectively, during acute challenge. However, fasudil infusion resulted in a more pronounced increase in mean cardiac output and mixed venous oxygen saturation compared with iloprost inhalation (13.7±17.1% vs. 6.9±15.0%; p=0.044 and 4.5±5.3% vs. 2.7±8.2%; p=0.044, respectively). Whereas inhaled iloprost resulted in a non-significant increase in mean systemic arterial oxygen saturation (0.8±3.6%), infused fasudil resulted in a non-significant reduction (−0.6±1.1%). ConclusionInfused fasudil improved pulmonary hemodynamics in patients with PAH without significant toxicity.

The Effect of Volume Loading on Systemic Oxygenation After Bidirectional Superior Cavopulmonary Anastomosis

The unique series arrangement of the cerebral and pulmonary circulation in bidirectional superior cavopulmonary anastomosis (BCPA) makes the pulmonary blood flow dependent upon the cerebral blood flow. Until now, several investigators have tried to correct post-BCPA hypoxemia with various methods such as induced hyperventilation, the addition of carbon dioxide, and inhaled nitric oxide with variable success rates. We prospectively studied 25 children with univentricular physiology undergoing BCPA surgery at 5 different time points in the preoperative (1 time point) and postoperative period (4 time points, each separated by at least 3 mm Hg changes in the superior vena cava [SVC] pressure). Intravenous fluids were administered in the postoperative period to raise the SVC pressure. The systemic arterial oxygen saturation (Sao2) increased significantly (p = 0.000) from a preoperative value of 80% ± 7% to 86% ± 7%, 91% ± 3% and 95% ± 4% at SVC pressures of 9 ± 1.6 mm Hg, 13 ± 1.3 mm Hg, and 16 ± 1.4 mm Hg, respectively, and then decreased to 94% ± 4% at SVC pressure of 20 ± 1.7 mm Hg. Systolic and diastolic blood pressure increased significantly and simultaneously with SVC pressure from 71 ± 8 mm Hg and 42 ± 6 mm Hg to 89 ± 11 mm Hg and 52 ± 7 mm Hg, respectively (p = 0.000). Administration of intravenous fluids improves the SVC pressure, possibly due to an increase in the cerebral blood flow and the SVC flow, and thus raises the arterial oxygen tension (Pao2) and Sao2. Each patient has a unique SVC pressure where the Sao2 and the Pao2 are maximum; beyond that limit, the Sao2 does not improve.