Clinical significance of assessing cerebral blood volume by time-domain near-infrared spectroscopy in children with congenital heart disease.

BACKGROUND: Despite providing cerebral tissue oxygen saturation (StO2 ), the lack of quantitative information for continuous wave near-infrared spectroscopy (CW-NIRS) is an obstacle in evaluating cerebral hemodynamic conditions. Time-domain NIRS (TD-NIRS) provides both StO2 and cerebral blood volume and has recently become clinically available. AIM: To investigate if the additional monitoring of cerebral blood volume by TD-NIRS facilitates the understanding of cerebral hemodynamic conditions in patients with congenital heart disease. METHODS: Preoperative TD-NIRS values were retrospectively reviewed in patients who underwent a cardiac surgery or catheter examination. We compared the values between patients with single and two ventricles. Moreover, we investigated the association of these values with the demographic and clinical variables. RESULTS: There was no significant difference in StO2 between single ventricle and two ventricles groups (median: 59.9 vs. 54.4, median difference [95% CI]: -4.06 [-9.90 to 2.90], p = .37). However, cerebral blood volume was significantly higher in the single ventricle group (median: 4.68 vs. 2.84, median difference [95% CI]: -2.01 [-2.88 to -1.06], p < .001). Spearman's rank correlation analysis demonstrated an association between StO2 and postmenstrual age (r = 0.35, p = .03). In contrast, cerebral blood volume was correlated with single ventricle physiology (r = 0.62, p < .001), postmenstrual age (r = 0.74, p < .001), central venous pressure (r = 0.38, p = .02), and SaO2 (r = -0.38, p = .02). The multivariable regression analysis identified the postmenstrual age, single ventricle physiology, and SaO2 as independent factors associated with cerebral blood volume. In the logistic analysis, cerebral blood volume was identified as a significant predictor of unfavorable conditions. CONCLUSION: Cerebral blood volume monitoring detected differences in cerebral hemodynamic conditions, related to the age and the type of ventricle physiologies. However, the differences were not apparent in StO2 . The additional monitoring of cerebral blood volume by TD-NIRS would facilitate a better understanding of cerebral hemodynamic conditions in patients with congenital heart disease.

High-flow Nasal Cannula Versus Noninvasive ventilation for Postextubation Acute Respiratory Failure after Pediatric Cardiac Surgery.

We compared the reintubation rate in children who received high-flow nasal cannula (HFNC) therapy to the rate in children who received noninvasive ventilation (NIV) therapy for acute respiratory failure (ARF) after cardiac surgery. This was a retrospective analysis of 35 children who received HFNC therapy for ARF after cardiac surgery in 2014-2015 (the HFNC group). We selected 35 children who had received NIV therapy for ARF after cardiac surgery in 2009-2012 as a control group. The matching parameters were body weight and risk adjustment for congenital heart surgery category 1. The reintubation rate within 48 h in the HFNC group tended to be lower than that in the NIV group (3% vs. 17%, p=0.06). The reintubation rate within 28 days was significantly lower in the HFNC group compared to the NIV group (3% vs. 26%, p=0.04). The HFNC group's ICU stays were significantly shorter than those of the NIV group: 10 (IQR: 7-17) days vs. 17 (11-32) days, p=0.009. HFNC therapy might be associated with a reduced reintubation rate in children with ARF after cardiac surgery.

Incidence of Pulmonary Complications with the Prophylactic Use of High-flow Nasal Cannula after Pediatric Cardiac Surgery: Prophylactic HFNC Study Protocol.

We will investigate the incidence of postoperative pulmonary complications (PPCs) with the prophylactic use of a high-flow nasal cannula (HFNC) after pediatric cardiac surgery. Children < 48 months old with congenital heart disease for whom cardiac surgery is planned will be included. The HFNC procedure will be commenced just after extubation, at a flow rate of 2 L/kg/min with adequate oxygen concentration to achieve target oxygen saturation ≥ 94%. This study will reveal the prevalence of PPCs after pediatric cardiac surgery with the prophylactic use of HFNC.

High Ionized Calcium Concentration Is Associated With Prolonged Length of Stay in the Intensive Care Unit for Postoperative Pediatric Cardiac Patients.

OBJECTIVE: There has been controversy regarding the beneficial effects of calcium on myocardial contractility and the harmful effects on myocardial cells, especially in children. The aim of this study was to investigate an association between ionized calcium concentration (iCa) and outcomes for pediatric patients after cardiac surgery. DESIGN: A retrospective, single-center study from May 2013 to December 2014. SETTING: Referral high-volume pediatric cardiac center in a tertiary teaching hospital. PATIENTS: Patients <72 months old with congenital heart disease who underwent palliative or definitive surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The association between pH-corrected iCa within 24 hours after surgery and intensive care unit (ICU) length of stay (ILOS) was defined as the primary outcome. The highest iCa (iCamax), lowest iCa (iCamin), and time-weighted average iCa (iCaave) were stratified and compared with the outcomes. The authors reviewed 5,468 ionized calcium measurements from 357 consecutive pediatric patients during the study period. One patient died at postoperative day 34 in the ICU. Significant differences in ILOS were observed among patients after cardiopulmonary bypass (CPB) according to iCaave, iCamax, and iCamin but not among patients without CPB. Patients with CPB and an iCaave value of 1.31-to-1.40 mmol/L, 1.41-to-1.50 mmol/L, 1.51-to-1.60 mmol/L, and >1.60 mmol/L stayed in the ICU for 7 (interquartile range [IQR] 4-10) days, 8 (IQR 6-16) days, 10 (IQR 8-14) days, and 19 (IQR 12-38) days, respectively, which was significantly longer than the ILOS of 5 (4-8) days for patients with an iCaave of 1.21-to-1.30 mmol/L. Even after adjustment for other predictors of ILOS using multivariable analyses, there were significant relationships of ILOS with iCaave and iCamin values of >1.50 mmol/L among patients with CPB. CONCLUSIONS: Higher iCa within 24 hours after congenital cardiac surgery using CPB was independently associated with longer LOS in the ICU.

Physiological impact of high-flow nasal cannula therapy on postextubation acute respiratory failure after pediatric cardiac surgery: a prospective observational study.

BACKGROUND: Reintubation after pediatric cardiac surgery is associated with a high rate of mortality. Therefore, adequate respiratory support for postextubation acute respiratory failure (ARF) is important. However, little is known about the physiological impact of high-flow nasal cannula (HFNC) therapy on ARF after pediatric cardiac surgery. Our working hypothesis was that HFNC therapy for postextubation ARF after pediatric cardiac surgery improves hemodynamic and respiratory parameters. METHODS: This was a prospective observational study conducted at a single university hospital. Children less than 48 months of age who had postextubation ARF after cardiac surgery were included in this study. HFNC therapy was started immediately after diagnosis of postextubation ARF. Data obtained just before starting HFNC therapy were used for pre-HFNC analysis, and data obtained 1 h after starting HFNC therapy were used for post-HFNC analysis. We compared hemodynamic and respiratory parameters between pre-HFNC and post-HFNC periods. The Wilcoxon signed-rank test was used to analyze these indices. RESULTS: Twenty children were included in this study. The median age and body weight were 4.5 (2.3-14.0) months and 4.3 (3.1-7.1) kg, respectively. Respiratory rate (RR) significantly decreased from 43.5 (32.0-54.8) to 28.5 (21.0-40.5) breaths per minute (p = 0.0008) 1 h after the start of HFNC therapy. Systolic blood pressure also decreased from 87.5 (77.8-103.5) to 76.0 (70.3-85.0) mmHg (p = 0.003). Oxygen saturation, partial pressure of arterial carbon dioxide, heart rate, and lactate showed no remarkable changes. There was no adverse event caused by HFNC therapy. CONCLUSIONS: HFNC therapy improves the RR of patients who have postextubation ARF after pediatric cardiac surgery without any adverse events.

Cerebral oxygen saturation and tissue hemoglobin concentration as predictive markers of early postoperative outcomes after pediatric cardiac surgery.

BACKGROUND: Near-infrared spectroscopy (NIRS) provides an assessment of cerebral oxygenation and tissue hemoglobin concentration. AIM: The aim of this study was to investigate whether the cerebral oxygenation and hemoglobin concentration measured with NIRS could predict outcomes after pediatric cardiac surgery. METHOD: We conducted a retrospective observational study in 399 patients who underwent pediatric cardiac surgery. Associations were determined between postoperative outcome and preoperative and postoperative cerebral tissue oxygenation index (TOI), postoperative normalized tissue hemoglobin index (nTHI), concentration changes in oxygenated hemoglobin (Δ[HbO2 ]) and deoxygenated hemoglobin (Δ[HHb]). RESULTS: Thirty-nine children had major postoperative morbidity and 12 died. Using Spearman's correlation analysis, postoperative lower TOI and higher Δ[HHb] were associated with longer stays in the Intensive Care Unit (ICU) (r = -0.48, P < 0.001, r = 0.31, P < 0.001, respectively) and longer duration of intubation (r = -0.48, P < 0.001, r = 0.31, P < 0.001, respectively) and higher probability of death determined by the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1) (r = -0.39, P < 0.001, r = 0.23, P < 0.001, respectively). In multivariate regression analysis, postoperative TOI was independently associated with major morbidity and mortality and Δ[HHb] was independently associated with major morbidity. In receiver operating characteristic analysis, postoperative TOI and Δ[HHb] predicted major morbidity (Area under the curve [AUC] = 0.72, 0.68, respectively) and mortality (AUC = 0.81, 0.69, respectively). CONCLUSION: Lower TOI or higher [HHb] at the end of surgery and higher RACHS-1 category predicted worse outcomes.

[Intracranial Hemorrhage and Pneumocephalus after Spinal Cord Tumor Resection: A Case Report].

A 75-year-old woman was scheduled for spinal cord tumor resection. General anesthesia was induced and maintained using propofol, remifentanil and fentanyl. Aside from fluctuations in intraoperative blood pres- sure, the surgery was uneventful, but emergence from anesthesia was delayed and the patient showed partial paralysis. Emergent brain CT revealed multiple intracranial hemorrhages and pneumocephalus. Since a large amount of fluid was observed from the drainage tube at the surgical site, loss of cerebrospinal fluid and subsequent low intracranial pressure were considered to be the cause of the hemorrhage and pneumocepha- lus. Intracranial hemorrhage and pneumocephalus are rare complications after spinal surgery, but they can lead to serious neurological dysfunction. Dural tear and/or excessive drainage are considered to be the causes of these complications, and careful observation of the property, amount and rate of drainage is there- fore warranted.

[Pacing lead extraction using an excimer laser sheath under general anesthesia].

An excimer laser sheath has recently been used for extraction of pacing and ICD leads. By using this technique, leads are removed more easily and it has to take a shorter time to extract leads. Although lead extraction with this method can cause fatal complications such as large vessel injury, little has been reported regarding anesthetic management during the lead extraction. We experienced two cases of pacing lead extraction using an excimer laser sheath under general anesthesia. The procedures were mainly performed by cardiologists in the operating theater. A wide area was prepared with sterile drapes as for cardiac surgery with cardiovascular surgeons standing by. Vascular access catheters were placed in the right femoral artery as well as vein, and in the right internal jugular vein so that immediate PCPS introduction could be performed in case of sudden hemodynamic collapse by massive bleeding. In the first case, lead extraction was completed without any complication, but in the second case sternotomy was performed by cardiac surgeons for safe separation of leads from vessels. There were also no bleeding episodes in the second case. Preparation for bleeding and cooperation among cardiologists, cardiovascular surgeons, medical engineers and anesthesiologists are necessary from the safety point of view of this procedure under general anesthesia.

[General anesthesia for pediatric cardiac catheterization--effects of anesthetics on blood pressure, heart rate, oxygen saturation, and carbon dioxide].

BACKGROUND: There are limited data about the correlations between amount of anesthetics and variations in vital signs during pediatric cardiac catheterization. METHODS: Data in 80 children with congenital heart disease undergoing cardiac catheterization with/without interventional cardiology in 2004 were examined in this retrospective cohort study. Data on blood pressure, heart rate, oxygen saturation, partial tension in end tidal carbon dioxide (PETCO2), and total amount of anesthetics given during general anesthesia were obtained from anesthetic charts. The correlations between amount of anesthetics and those vital signs were analyzed. RESULTS: Median age of the patients was 14 months and median body weight was 8.8 kg. Median rates of variation in heart rate, blood pressure, oxygen saturation and PET(CO2) were 22.8%, 29.3%, 5.9% and 10.8%, respectively. Although there were no statistical correlations between those vital signs and amounts of anesthetics such as fentanyl, vecuronium and sevoflurane, rates of variation in heart rate was smaller in patients for whom the amount of fentanyl given was more than 4 microg x kg(-1) x hr(-1). CONCLUSIONS: There were no associations between amount of anesthetics and variations in vital signs in pediatric cardiac catheterization.

Effect of tranexamic acid on blood loss in pediatric cardiac surgery: a randomized trial.

PURPOSE: The benefit of tranexamic acid (TXA) in pediatric cardiac surgery on postoperative bleeding has varied among studies. It is also unclear whether the effects of TXA differ between cyanotic patients and acyanotic patients. The aim of this study was to test the benefit of TXA in pediatric cardiac surgery in a well-balanced study population of cyanotic and acyanotic patients. METHODS: A total of 160 pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (81 cyanotic, 79 acyanotic) were included in this single-blinded, randomized trial at a tertiary care university-affiliated teaching hospital. Eighty-one children (41 cyanotic, 40 acyanotic) were randomly assigned to a TXA group, in which they received 50 mg/kg of TXA as a bolus followed by 15 mg/kg/h infusion and another 50 mg/kg into the bypass circuit. The other 79 patients were randomly assigned to a placebo group. The primary end point was the amount of 24-h blood loss. RESULTS: The amount of 24-h blood loss was significantly less in the TXA group than in the placebo group [mean (95% confidence interval): 18.6 (15.8-21.4) vs. 23.5 (19.4-27.5) ml/kg, respectively; mean difference -4.9 (-9.7 to -0.01) ml/kg; p = 0.049]. This effect of TXA was already significant at 6 h [9.5 (7.5-11.5) vs. 13.2 (10.6-15.9) ml/kg, respectively; mean difference -3.47 (-7.0 to -0.4) ml/kg; p = 0.027]. However, there was no significant difference in the amount of blood transfusion between the groups. There was also no statistical difference in the effect of TXA in each cyanotic and acyanotic subgroup. CONCLUSION: TXA can reduce blood loss in pediatric cardiac surgery but not the transfusion requirement (http://ClinicalTrials.gov number NCT00994994).

[Postoperative coil embolization of residual MAPCAs greatly improved left heart failure in a patient after corrective surgery for pulmonary atresia, ventricular septal defect and MAPCAs].

A male child, aged 1 year, with pulmonary atresia, ventricular septal defect and major aorto-pulmonary collateral arteries (PA, VSD, MAPCA) underwent corrective surgery including MAPCA ligation uneventfully. A few hours after admission to the ICU, severe heart failure, refractory to aggressive cardiac support including epinephrine infusion, became worse. Emergent cardiac catheterization on postoperative day 5 demonstrated the residual MAPCA and its occlusion by coil embolization dramatically resolved heart failure, indicating that the primary cause of this hemodynamic instability was likely excessive left-to-right shunt due to MAPCA. Residual LR shunt should be kept in mind to be a rare but significant cause of postoperative serious heart failure.

[Successful use of intravenous amiodarone for refractory ventricular fibrillation just after releasing aortic cross-clamp].

Amiodarone is widely used in Europe and the United States for refractory ventricular fibrillation (VF) in various situations, such as VF after myocardial infarction or out-of-hospital cardiac arrest. We report a case of successful treatment with amiodarone of refractory VF immediately after releasing aortic cross-clamp in cardiac surgery. A 66-year-old man suffering from severe aortic stenosis underwent aortic valve replacement (AVR). General anesthesia was induced with propofol and remifentanil, and subsequently AVR was performed under cardiopulmonary bypass. Just after releasing aortic cross-clamp, VF occurred, and it continued despite multiple trials of cardioversion with direct current (DC) shocks of 20 J or 30 J. Furthermore, some DC shocks of 30 J or 50 J after administering lidocaine 60 mg and 0.5 mol x l(-1) magnesium sulfate 20 ml were also ineffective. Then, nifekalant 20 mg was administered and DC shocks of 50 J were repeated intermittently, but VF still persisted. Eventually, VF disappeared after a final DC shock of 50 J with intravenous amiodarone 125 mg. Overall duration of VF was 60 minutes. The patient's trachea was extubated three days after the surgery without any complications. Intravenous amiodarone may be one of the most useful remedies for some types of arrhythmias including persistent VE.

[Perioperative management for open balloon atrial septostomy immediately after caesarean section in a baby with hypoplastic left heart syndrome and intact atrial septum].

Hypoplastic left heart syndrome (HLHS) with intact atrial septum (IAS) is an extreme type of single ventricle physiology among congenital heart diseases, in which a baby cannot supply oxygenated blood into systemic circulation without alternative pathway. We report the case of the neonate undergoing open balloon atrial septostomy (BAS) and bilateral pulmonary artery banding (PAB) soon after scheduled caesarean sections (C/S). A 35-year-old female was pregnant and fetal echocardiography at 32 weeks revealed one of the twins as HLHS/IAS. Severe hypoxia soon after birth was suspected. Thus, scheduled C/S followed by open BAS was planned. At 36 weeks of gestation, the mother was anesthetized with spinal bupivacaine and the female baby with HLHS/IAS was delivered. After diagnosed definitely by pediatric cardiologists, her trachea was intubated by anesthegiologists and umbilical catheters were placed by neonatologists. Then the baby was transferred to neighboring operating theater for BAS 68 minutes after the birth, while her Sp(O2) was maintained around 75-85% through serial procedures. Open BAS and PAB were performed under general anesthesia without any hemodynamic instability or severe hypoxia. Cooperation among anesthegiologists, neonatologists, pediatric cardiologists, and cardiac surgeons is mandatory in order to successfully complete such a rushed procedure.

Impairment of leukocyte deformability in patients undergoing esophagectomy.

Impaired deformability might contribute to the accumulation of activated leukocytes within pulmonary microcapillaries, leading to acute lung injury. The purpose of our study was to investigate changes in leukocyte deformability during periods of inflammation after esophagectomy. The study group comprised 20 patients who underwent esophagectomy. Changes in leukocyte deformability were investigated by examining filtration through a silicon microchannel, which simulated human pulmonary microcapillaries. Changes in the neutrophil cytoskeleton were investigated by measuring neutrophil F-actin assembly. The severity of patient clinical outcome was evaluated by the lung injury score. Leukocyte filtration through the microchannel was significantly weaker in esophagectomy patients than in healthy subjects (p<0.01). After esophagectomy, filtration was further impaired compared with preoperative values (p<0.05). The neutrophil F-actin content was higher in patients than in controls (p<0.01), and increased after esophagectomy compared with preoperative values (p<0.01). We concluded that circulating leukocytes showed reduced deformability and appeared to be sequestered within microcapillaries after esophagectomy. Changes in neutrophil cytoskeleton were considered to be responsible for the reduced deformability. Leukocyte accumulation within pulmonary microcapillaries might be related to the pathogenesis of lung injury after esophagectomy.

Analysis of cyclic-stretching responses using cell-adhesion-patterned cells.

Human vascular endothelial cells form the interface between the bloodstream and vessel walls and are continuously subjected to mechanical stimulation. When endothelial cells are stretched cyclically, along one axis, they align perpendicular to the axis of stretch. We previously reported that applying a cyclic, uni-axial strain to cells induced tyrosine phosphorylation of focal adhesion kinase and stimulated mitogen-activated protein kinase. However, it is difficult to quantify and analyze the spatial distribution of tyrosine phosphorylation in these cells, as they form focal adhesions randomly. In this study, we developed a system to overcome this problem by preparing individual, uniform, patterned cells that could be stretched cyclically and uni-axially. We constructed polydimethylsiloxane stretch chambers and used microcontact printing technology to imprint a pattern of 2 microm fibronectin dots (10 lines x 10 columns in a 38 microm square) before seeding them with human umbilical vein endothelial cells (HUVEC). We found that most HUVEC attached to the patterned dots after 2h and were similar in size and morphology, based on phase-contrast microscopy. In this system we were able to statistically analyze tyrosine phosphorylation and actin polymerization in these patterned cells, when subjected to a cyclic, uni-axial strain, using fluorescent microscopy.