Customized Two-Dimensional Computed Tomography-Guided Preoperative Pectus Bar Shaping.

INTRODUCTION: Successful minimally invasive repair of pectus excavatum relies on a pectus bar that closely conforms to the desired shape of the sternum and ribs to produce optimal elevation and remodeling. However, the present method of empirical intraoperative bar shaping is tedious and risks trauma to surrounding structures. To overcome this, we devised a technique using a life-sized computed tomography (CT) printout of the patient's chest wall to guide preoperative bar bending. METHODS: A 5-cm-wide polymethylmethacrylate block placed on the sternum as the patient underwent chest CT was used as a marker to guide scaling of an axial screenshot of the patient's chest to life-size. This life-size image was printed and the planned correction of the patient's chest wall was traced onto it. The pectus bar was bent according to this template. Patient demographics, Haller index, surgical indications, operative technique, complications, aesthetic and functional improvements, and overall satisfaction were assessed. RESULTS: Thirty patients (4 women) underwent primary minimally invasive repair of pectus excavatum with a single pectus bar shaped preoperatively over an 8-year period. The average age and Haller index was 20.6 years and 5.4, respectively. The mean operative time was 66.4 minutes. Satisfactory sternal elevation was attained with a single attempt at bar insertion in all cases. Two patients had pneumothoraxes that resolved without intervention. The mean follow-up period was 50.1 months. There were no cases of bar migration or recurrence of deformity after bar removal. On a 5-point Likert scale, all patients indicated an improvement in aesthetic appearance (4.6), and patients with physical symptoms (10) reported an improvement in function (4.4). The overall satisfaction score was 4.7. CONCLUSIONS: This technique of CT-guided preoperative pectus bar shaping is straightforward, eliminates the need for intraoperative revisions to bar shape, and achieves effective correction of the pectus excavatum deformity. All patients were satisfied with the aesthetic, functional, and overall outcomes.

Implementation of On-table Extubation After Pediatric Cardiac Surgery in the Developing World.

In the recent years there has been increasing trend towards the practice of on-table extubation after pediatric cardiac surgery among practitioner in European and non-European countries. In this article we share our experience with on-table extubation among children after cardiac surgery in the developing world supported with the currently available literature.

Influence of clinical experience of the Macintosh laryngoscope on performance with the Pentax-AWS Airway Scope(®), a rigid video-laryngoscope, by paramedics in Japan.

PURPOSE: We sought to establish the clinical utility of the Pentax-AWS Airway Scope(®) (AWS) when used by paramedics to intubate the trachea, and to evaluate whether their performance was influenced by previous clinical experience with the Macintosh laryngoscope (ML). METHODS: Twenty paramedics attempted tracheal intubation using the AWS in five patients each in the operating room. We recorded the success rate, the number of intubation attempts, and the time for intubation and adverse events, and compared these based on the paramedics' previous clinical experience with the ML. Ten paramedics had no prior clinical experience of the ML (group A) and 10 had used it on more than 30 occasions (group B). RESULTS: The intubation success rate was 99 % (99/100). Notably, 96 % (47/49) of intubations were achieved on the first attempt by the inexperienced paramedics in group A, compared with 64 % (32/50) by the experienced paramedics in group B (p = 0.0001). The time to intubation (mean ± SD) was significantly shorter in group A than in group B (37 ± 24 vs. 48 ± 21 s, p = 0.002). There were marked variations in the times taken to intubate, but no apparent improvement as the intubators gained experience between their first and fifth cases. No complications were encountered in either group. CONCLUSION: We found that paramedics could achieve a high tracheal intubation success rate using the AWS independent of previous airway management experience. Better intubation performance with the AWS was observed in paramedics without clinical experience with the ML.

Detection of the full-length transcript variant for neurokinin-1 receptor in human whole blood associated with enhanced reinforcement of clot by substance-P.

We have recently reported that a neurotransmitter for pain, substance-P (SP), promotes platelet-dependent clot formation through neurokinin-1 receptors (NK1Rs), in which leukocytes appear to be involved (J Thromb Thrombolysis 2009;27:280-6). Two naturally occurring splice isoforms of NK1R with different signal transduction potency, namely the full-length and the truncated NK1Rs are identified. It is known that human leukocytes express truncated NK1Rs, while in vivo expression of the full-length NK1R has not yet been fully clarified. Modulatory effects of alternative splicing for NK1Rs on clot formation also remain to be evaluated. Expression of the transcript variant mRNA for NK1Rs in human whole blood (n = 20) was evaluated by real-time reverse transcription polymerase chain reaction (RT-PCR). A 15 min time series of the strength of clot, formed after reloading of calcium in citrated whole blood with or without SP (10 nM) and a NK1R antagonist Spantide (1 µM), was measured by using oscillating-probe viscoelastometry. The full-length transcript variant was detected in 5 samples among 20. SP significantly increased the clot strength while Spantide suppressed the SP-derived change. The extent of modulation by SP/NK1R pathway in a subgroup with expression of the full-length transcript variant was three times as potent as those in another subgroup without expression. We conclude that expression of the full-length transcript variant for NK1R can be detected in human whole blood and that such expression is associated with the enhanced reinforcement of clot by SP. Further study is required to nominate this mRNA as a biomarker for prothrombotic risks in painful conditions such as perioperative period.

Abdominal aortic aneurysm in a child with tuberous sclerosis.

Abdominal aortic aneurysm is rare in the pediatric population and even more uncommon in association with tuberous sclerosis. We have presented a unique case of a 3-year, 8-month-old girl who was successfully treated. She was admitted because of breakthrough seizures. A painless pulsatile abdominal mass on examination prompted an abdominal ultrasound scan, which identified a large saccular abdominal aortic aneurysm. Urgent replacement of the abdominal aorta with a 12-mm woven Dacron graft was undertaken. A postoperative ultrasound evaluation confirmed the successful repair. She was growing well when examined 7 months after surgery.

Aortic intimal fold in Takayasu arteritis causing obstruction of left coronary ostium.

An 11-year-old girl with Takayasu arteritis was presented with recurrent chest pain. A transthoracic echocardiogram showed moderate to severe aortic regurgitation with impaired cardiac function. Cardiac catheterization revealed the total occlusion of the small right coronary artery and left main stenosis of 40%. An intraoperative transesophageal echocardiogram showed a redundant intimal fold partially covering the left coronary ostium and this was further confirmed from the intraoperative finding. This is a case report of recurrent angina associated with obstruction of left main coronary artery orifice by an intimal fold secondary to Takayasu arteritis.

How efficacious are Octreotide and Somatostatin in the management of chylothorax in congenital cardiac surgical patients?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was how efficacious are Octreotide and Somatostatin in the management of chylothorax in congenital cardiac surgical patients. Altogether >55 papers were found using the reported search, of which 8 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The comparative data on LOS and chylothorax duration are mixed though interpretation is difficult since Octreotide has been instituted belatedly from the onset of chylothorax in multiple instances. There is also preliminary evidence to suggest that responders to Somatostatin and Octreotide are affected by single-ventricle physiology and CVP levels. Meanwhile, non-responders tend to have higher mortality and may merit earlier surgical intervention. The included studies thus far have significant limitations such as low-level evidence study design, selection bias, variability in duration and dosage of therapy and heterogenous comparative arms. Notwithstanding these limitations, Octreotide has shown to be an useful adjunct treatment in reducing chylothorax volume especially in patients with higher output chylothorax (>40 ml/kg/h) after the failure of conservative management.

Combination of slide tracheoplasty and side-to-side bronchoplasty for complex congenital tracheobronchial stenosis.

Congenital tracheal stenosis is a rare but serious condition with high mortality and morbidity. We present a 6-month-old patient with complex congenital tracheal stenosis involving the trachea, carina and right bronchus intermedius, which was corrected with a combination of slide tracheoplasty and side-to-side bronchoplasty.

Congenital left atrial appendage aneurysm with unexpected course of left anterior descending coronary artery.

The left atrial appendage (LAA) aneurysm is a rare condition that can produce local compressive effects and complications including supraventricular tachyarrhythmias, thromboembolic events and myocardial ischaemia. We present a rare case of a neonate with a congenital LAA aneurysm which resulted in local compressive effects on the left ventricle, severe mitral regurgitation and malposition of the left anterior descending (LAD) coronary artery. Intraoperatively, the LAD was found to be within the aneurysmal wall exterior to the left ventricular epicardium and was inadvertently injured during LAA aneurysm resection. Retrospective review of the preoperative computed tomography and echocardiography scans demonstrated the LAD lying within the wall of the LAA aneurysm, although this had not been well appreciated at that time. This highlights the importance of thorough multimodal preoperative imaging and intraoperative assessment for recognition of this rare association between the LAA aneurysm and LAD malposition, and prevention of inadvertent LAD injury during aneurysm resection.

Congenital diaphragmatic hernia repair in patients requiring extracorporeal membrane oxygenation: are outcomes better with repair on ECMO or after decannulation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether congenital diaphragmatic hernia repair outcomes are better before or after decannulation in infants requiring extracorporeal membrane oxygenation (ECMO). A total of 884 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that infants with congenital diaphragmatic hernia requiring ECMO should undergo a trial of weaning and aim for post-decannulation repair, as this has been associated with improved survival, shorter ECMO duration and fewer bleeding complications. However, if weaning of ECMO is unsuccessful, the patient should ideally undergo early on-ECMO repair (within 72 h of cannulation), which has been associated with improved survival, less bleeding, shorter ECMO duration and fewer circuit changes compared to late on-ECMO repair. Anticoagulation protocols including perioperative administration of aminocaproic acid or tranexamic acid, as well as close perioperative monitoring of coagulation parameters have been associated with reduced bleeding risk with on-ECMO repairs.

Multiscale modeling of a modified Blalock-Taussig surgery in a patient-specific tetralogy of Fallot.

Tetralogy of Fallot (TOF) is a congenital heart anomaly that causes a drastic reduction in the oxygen level. In this study, we coupled a lumped-parameter model with a patient-specific three-dimensional (3D) model which included a modified Blalock-Taussig (MBT) shunt. By forming a closed loop, we investigated the effects of certain parameters on the flow rates and the pressures at different locations of the developed network. A local sensitivity analysis on an initial zero-dimensional (0D) closed-loop model was conducted. The 0D lumped parameter (LP) model was then refined based on the results of the multiscale 0D-3D model and the local sensitivity analysis was repeated for the refined 0D model. It was shown that the maximum pressure of the pulmonary bed had the highest sensitivity of 94% to the diameter of MBT shunt. We observed that the existence of the flow in the shunt during the diastole caused an elevated wall shear stress (WSS) in the pulmonary artery. In this work, we calculated the flow velocity and pressure field in a 3D patient-specific aorta with an MBT shunt, and then we used the results to increase the accuracy of our LP model to simulate numerous 0D simulations in a significantly shorter time, which is potentially applicable for medical decision-making.

Fast tracking after repair of congenital heart defects.

Fast tracking after repair of congenital heart defects (CHD) is a process involving the reduction of perioperative period by timely admission, early extubation after surgery, short intensive care unit (ICU) stay, early mobilisation, and faster hospital discharge. It requires a coordinated multidisciplinary team involvement. In the last 2 decades, many centres have adopted the fast tracking strategy in paediatric cardiac population, safely and successfully extubating patients in the OR with reported benefits in terms of reduced morbidity and ICU/hospital stay. In this manuscript, we will review the literature available on early extubation after repair of CHD and share our experience with this approach.

Repair of pulmonary artery sling with tracheal and intracardiac defects.

BACKGROUND: Pulmonary artery sling is commonly associated with tracheal stenosis and intracardiac anomalies. While surgical repair is standardized, coexistent anomalies often determine outcomes. With the paucity of risk stratification, this study aimed to review our experience and stratify risk factors for the surgical outcome of complex pulmonary artery sling repair in the presence of airway or intracardiac lesions. METHODS: Seventy-nine consecutive children with pulmonary artery sling were evaluated retrospectively following surgical repair. Median age at surgery was 5 months (interquartile range 3-9). Surgical approaches included pulmonary artery sling alone (n = 10), pulmonary artery sling with tracheoplasty (n = 41), and pulmonary artery sling with both intracardiac and tracheal surgery (n = 28). RESULTS: There were 7 early (8.8%) deaths. Two patients after left pulmonary artery reimplantation needed revision of the anastomosis. The median intensive care and hospital stay were 11 (interquartile range 9.2-24.8) and 17.9 (interquartile range 4.3-19.8) days, and considerably longer when associated tracheal surgery (p = 0.002). Follow-up was complete in 66/69 and 3 (3.8%) children died late: 2.7, 10.2, and 17 months after surgery. Univariate analysis showed abnormal lung and coexisting structural heart disease as risk factors. Multivariate analysis revealed total cardiopulmonary bypass time as an independent predictor of overall mortality. CONCLUSION: Complex pulmonary artery sling repair can be performed with a good surgical outcomes even when associated with airway malformations or structural heart diseases. Lung abnormality and longer cardiopulmonary bypass time as a surrogate marker of complex surgery, are possible risk factors.

Prothrombotic roles of substance-P, neurokinin-1 receptors and leukocytes in the platelet-dependent clot formation in whole blood.

A number of types of non-neuronal cells including leukocytes have been confirmed to possess substance-P and its specific neurokinin-1 receptor (NK1R), while the pathophysiological roles of substance-P in these cells remain to be established. Effects of substance-P through NK1R on platelet-dependent clot formation were evaluated by using an oscillating-probe viscoelastometer. The clot signal, indicative of the clot strength in blood-derived samples, was measured after the stimulation with celite and Ca(2+). Substance-P (10 nM) increased the clot signal of whole blood obtained from healthy volunteers, especially modulating the platelet-dependent distinctive peak in traces of the signal. A NK1R antagonist Spantide (500 nM) blocked such substance-P derived change, suggesting the involvement of platelets in the action of substance-P. In contrast, substance-P did not increase the clot signal of platelet-containing but leukocyte-removed plasma. From these, we conclude that substance-P promotes platelet-dependent clot formation through NK1R, in which leukocytes appear to be involved.

In vitro Assessment of the Impacts of Leaflet Design on the Hemodynamic Characteristics of ePTFE Pulmonary Prosthetic Valves.

Prosthetic pulmonary valves are widely used in the management procedures of various congenital heart diseases, including the surgical pulmonary valve replacement (PVR) and right ventricular outflow tract reconstruction (RVOT). The discouraging long-term outcomes of standard prostheses, including homografts and bioprosthetic, constrained their indications. Recent developments in the expanded-polytetrafluoroethylene (ePTFE) pulmonary prosthetic valves provide promising alternatives. In this study, the hemodynamic characteristics of bileaflet and trileaflet ePTFE valve designs were experimentally evaluated. The in vitro tests were performed under the right ventricle (RV) flow conditions by using an in vitro RV circulatory system and particle image velocimetry (PIV). The leaflet kinetics, trans-valvular pressure gradients, effective orifice areas, regurgitant fractions, energy losses, velocity fields, and Reynolds shear stress (RSS) in both prostheses were evaluated. The opening of the bileaflet and trileaflet valve takes 0.060 and 0.088 s, respectively. The closing of the former takes 0.140 s, in contrast to 0.176 s of the latter. The trans-valvular pressure is 6.8 mmHg in the bileaflet valve vs. 7.9 mmHg in the trileaflet valve. The effective orifice area is 1.83 cm2 in the bileaflet valve and 1.72 cm2 in the trileaflet valve. The regurgitant fraction and energy loss of bileaflet are 7.13% and 82 mJ, which are 7.84% and 101.64 mJ in its bileaflet counterpart. The maximum RSS of 48.0 and 49.2 Pa occur at the systole peak in the bileaflet and trileaflet valve, respectively. A higher average RSS level is found in the bileaflet valve. The results from this preliminary study indicate that the current bileaflet prosthetic valve design is capable of providing a better overall hemodynamic performance than the trileaflet design.

Numerical and in-vitro experimental assessment of the performance of a novel designed expanded-polytetrafluoroethylene stentless bi-leaflet valve for aortic valve replacement.

The expanded polytetrafluoroethylene (ePTFE) heart valve can serve as a viable option for prosthetic aortic valve. In this study, an ePTFE bi-leaflet valve design for aortic valve replacement (AVR) is presented, and the performance of the proposed valve was assessed numerically and experimentally. The valve was designed using CAE software. The dynamic behavior of the newly designed bi-leaflet valve under time-varying physiological pressure loading was first investigated by using commercial finite element code. Then, in-vitro tests were performed to validate the simulation and to assess the hemodynamic performance of the proposed design. A tri-leaflet ePTFE valve was tested in-vitro under the same conditions as a reference. The maximum leaflet coaptation area of the bi-leaflet valve during diastole was 216.3 mm2. When fully closed, no leakage gap was observed and the free edges of the molded valve formed S-shaped lines. The maximum Von Mises stress during a full cardiac cycle was 4.20 MPa. The dynamic performance of the bi-leaflet valve was validated by the in-vitro test under physiological aortic pressure pulse. The effective orifice area (EOA), mean pressure gradient, regurgitant volume, leakage volume and energy loss of the proposed valve were 3.14 cm2, 8.74 mmHg, 5.93 ml/beat, 1.55 ml/beat and 98.99 mJ, respectively. This study reports a novel bi-leaflet valve design for AVR. The performance of the proposed valve was numerically and experimentally assessed. Compared with the reference valve, the proposed design exhibited better structural and hemodynamic performances, which improved valve competency. Moreover, the performance of the bi-leaflet design is comparable to commercialized valves available on the market. The results of the present study provide a viable option for the future clinical applications.

[Diagnosis and transfusion algorithm for the management of perioperative coagulopathy].

The present article reviewed the management of coagulopathy in the perioperative setting, following the Japanese practical guidelines for the blood component therapy, edited by the Ministry of Health, Labour and Welfare of Japan in 2005. The threshold concentrations of platelets, prothrombin time international normalized ratio (PT-INR) and activated partial thromboplastin time (APTT) were optimized for the perioperative critical care under active and/or microvascular bleeding, based on currently available randomized controlled trials. Discontinuation or modification of anticoagulants as well as antiplatelets is essential for the safe perioperative care. Several factors, including normothermia, normovolemia, as well as the maintenance of plasma calcium levels within normal range, are important for the management of coagulopathy. Platelet counts, PT, APTT, and if possible, other point-of-care testing including thromboelastography and its modified techniques should be performed following visual inspection of abnormal bleeding. The transfusion algorithms based on causal diagnosis of coagulopathy optimize the risk/ benefit ratio of perioperative transfusion therapy.

Prevention of Acute Kidney Injury in Children Undergoing Cardiac Surgery: A Narrative Review.

Children undergoing cardiac surgery are at risk of developing acute kidney injury (AKI). Preventing cardiac surgery-associated AKI (CS-AKI) is important as it is associated with increased early- and long-term mortality and morbidity. Targeting modifiable risk factors (eg, avoiding poor renal perfusion, nephrotoxic drugs, and fluid overload) reduces the risk of CS-AKI. There is currently no strong evidence for the routine use of pharmacological approaches (eg, aminophylline, dexmedetomidine, fenoldopam, and steroids) to prevent CS-AKI. There is robust evidence to support the role of early peritoneal dialysis as a nonpharmacologic approach to prevent CS-AKI.

Changes in Near-Infrared Spectroscopy After Congenital Cyanotic Heart Surgery.

BACKGROUND: Since oxygen saturation from pulse oximetry (SpO2) and partial pressure of arterial oxygen (PaO2) are observed to improve immediately after surgical correction of cyanotic congenital heart disease (CHD), we postulate that cerebral (CrO2) and somatic (SrO2) oximetry also improves immediately post-correction. We aim to prospectively examine CrO2 and SrO2, before, during, and after surgical correction as well as on hospital discharge in children with cyanotic CHD to determine if and when these variables increase. METHODS: This is a prospective observational trial. Eligibility criteria included children below 18 years of age with cyanotic CHD who required any cardiac surgical procedure. CrO2 and SrO2 measurements were summarized at six time-points for comparison: (1) pre-cardiopulmonary bypass (CPB); (2) during CPB; (3) post-CPB; (4) Day 1 in the pediatric intensive care unit (PICU); (5) Day 2 PICU; and (6) discharge. Categorical and continuous variables are presented as counts (percentages) and median (interquartile range), respectively. RESULTS: Twenty-one patients were analyzed. 15 (71.4%) and 6 (28.6%) patients underwent corrective and palliative surgeries, respectively. In the corrective surgery group, SpO2 increased immediately post-CPB compared to pre-CPB [99 (98, 100) vs. 86% (79, 90); p < 0.001] and remained in the normal range through to hospital discharge. Post-CPB CrO2 did not change from pre-CPB [72.8 (58.8, 79.0) vs. 72.1% (63.0, 78.3); p = 0.761] and even decreased on hospital discharge [60.5 (53.6, 62.9) vs. 72.1% (63.0, 78.3); p = 0.005]. Post-CPB SrO2 increased compared to pre-CPB [87.3 (77.2, 89.5) vs. 72.7% (65.6, 77.3); p = 0.001] but progressively decreased during PICU stay to a value lower than baseline at hospital discharge [66.9 (57.3, 76.9) vs. 72.7% (65.6, 77.3); p = 0.048]. CONCLUSION: CrO2 and SrO2 did not increase after corrective surgery of cyanotic CHD even up to hospital discharge. Future larger studies are required to validate these findings. (This study is registered with ClinicalTrials.gov ID: NCT02417259.).

Neonatal airway: challenging endotracheal intubation in infants with tracheal malformations at birth.

Intubating newborn infants can be exacting. We describe two cases of endotracheal intubations in infants born with tracheal malformations. A male infant aged 30 weeks required intubation at birth for respiratory distress. Repeated attempts at intubation failed to achieve an optimal endotracheal tube position as the tube could not advance beyond the vocal cords. Hence ventilation continued with suboptimal air entry in the lungs. Bronchoscopy and CT scan confirmed tracheal stenosis. Slide tracheoplasty was successfully executed on day 78 of life. A female infant aged 33 weeks was intubated at birth for perinatal depression. Attempts at intubation were unsuccessful due to non-visualisation of the laryngeal inlet. Oesophagus was intubated and attempts to inflate showed air entry in the lungs, suggesting a fistulous communication between oesophagus and airway. A contrast oesophagogram showed a fistula connecting oesophagus and carina. With airway patency in question and associated major anomalies, parents were counselled and support was withdrawn.