Intraoperative and postoperative risk factors for prolonged mechanical ventilation after pediatric cardiac surgery

Pediatric cardiac surgery: machine learning models for postoperative complication prediction

PURPOSE

Managing children undergoing cardiac surgery with cardiopulmonary bypass (CPB) presents a significant challenge for anesthesiologists. Machine Learning (ML)-assisted tools have the potential to enhance the recognition of patients at risk of complications and predict potential issues, ultimately improving outcomes.

METHODS

We evaluated the prediction capacity of six models, ranging from logistic regression to support vector machine, using a dataset comprising 33 variables and 1364 subjects. The Area Under the Curve (AUC) and the F1 score served as the primary evaluation metrics. Our primary objectives were twofold: first, to develop an effective prediction model, and second, to create a user-friendly comprehensive model for identifying high-risk patients.

RESULTS

The logistic regression model demonstrated the highest effectiveness, achieving an AUC of 83.65%, and an F1 score of 0.7296, with balanced sensitivity and specificity of 77.94% and 76.47%, respectively. In comparison, the comprehensive three-layer decision tree model achieved an AUC of 72.84%, with sensitivity (79.41%) comparable to more complex models.

CONCLUSION

Our machine learning-assisted tools provide an additional perspective and enhance the predictive capabilities of traditional scoring methods. These tools can assist anesthesiologists in making well-informed decisions. Furthermore, we have successfully demonstrated the feasibility of creating a practical white-box model. The next steps involve conducting clinical validation and multicenter cross-validation.

TRIAL REGISTRATION

NCT05537168.

Perioperative Factors and Radiographic Severity Scores for Predicting the Duration of Mechanical Ventilation After Arterial Switch Surgery

OBJECTIVES

Cardiac surgery on cardiopulmonary bypass (CPB) during the neonatal period can cause perioperative organ injuries. The primary aim of this study was to determine the incidence and risk factors associated with postoperative mechanical ventilation duration and acute lung injury after the arterial switch operation (ASO). The secondary aim was to examine the utility of the Brixia score for characterizing postoperative acute lung injury (ALI).

DESIGN

A retrospective study.

SETTING

A single-center university hospital.

PARTICIPANTS

A total of 93 neonates with transposition of great arteries with intact ventricular septum (dTGA IVS) underwent ASO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From January 2015 to December 2022, 93 neonates with dTGA IVS were included in the study. The cohort had a median age of 4.0 (3.0-5.0) days and a mean weight of 3.3 ± 0.5 kg. About 63% of patients had ≥48 hours of postoperative mechanical ventilation after ASO. Risk factors included prematurity, post-CPB transfusion of salvaged red cells, platelets and cryoprecipitate, and postoperative fluid balance by univariate analysis. The larger transfused platelet volume was associated with the risk of ALI by multivariate analysis. The median baseline Brixia scores were 11.0 (9.0-12.0) and increased significantly in the postoperative day 1 in patients who developed moderate ALI 24 hours after admission to the intensive care unit (15.0 [13.0-16.0] v 12.0 [10.0-14.0], p = 0.046).

CONCLUSIONS

Arterial switch operation results in a high incidence of ≥48-hour postoperative mechanical ventilation. Blood component transfusion is a potentially modifiable risk factor. The Brixia scores also may be used to characterize postoperative acute lung injury.

The choice of perioperative inotropic support impacts the outcome of small infants undergoing complex cardiac surgery: an observational study

BACKGROUND

Vaso-inotropic agents are frequently used to prevent and/or treat low cardiac output syndrome in infants undergoing surgery for congenital heart disease. Due to the lack of comparative studies, their use is largely dependent on physician- and center preferences. The aim was to assess the impact of two different inotropic regimens, milrinone-epinephrine versus dobutamine on postoperative morbi-mortality in young children undergoing complex cardiac surgery.

METHODS

All consecutive children younger than one year of age admitted for complex cardiac surgery (Risk Adjustment in Congenital Heart Surgery-1 [RACHS-1] score ≥3) with cardiopulmonary bypass (CPB) from January 2008 to December 2018 were included. Children received either milrinone in association with low dose epinephrine (milrinone-epinephrine group) or dobutamine (dobutamine group) groups were matched and compared using a propensity score. Our primary outcome was a composite measure including either hospital death and/or the presence of at least two of the following events: respiratory failure, prolonged inotropic support, or renal failure.

RESULTS

Two hundred and fifty patients were included in the analysis. Children in the milrinone-epinephrine group (N.=184) suffered more frequently from a cyanotic heart disease and had longer surgery, CPB, and aortic cross clamp times than those in the dobutamine group (N.=66). After matching, children in the milrinone-epinephrine group had a higher incidence of severe postoperative morbidity or mortality compared to those in the dobutamine group (27.4 versus 13.9%; P=0.016). Respiratory failure (28% vs. 12%), prolonged inotropic support (71% vs. 35%) and in-hospital death (3 vs. 0%) were more frequent in the milrinone-epinephrine group.

CONCLUSIONS

In young infants undergoing complex cardiac surgery, milrinone combined with epinephrine is associated with a higher incidence of postoperative morbidity or mortality compared to dobutamine for perioperative inotropic support. Further prospective randomized studies are required to confirm this finding.

A simple-to-use nomogram for predicting prolonged mechanical ventilation for children after Ebstein anomaly corrective surgery: a retrospective cohort study

BACKGROUND

Prolonged mechanical ventilation (PMV) after pediatric cardiac surgery imposes a great burden on patients in terms of morbidity, mortality as well as financial costs. Ebstein anomaly (EA) is a rare congenital heart disease, and few studies have been conducted about PMV in this condition. This study aimed to establish a simple-to-use nomogram to predict the risk of PMV for EA children.

METHODS

The retrospective study included patients under 18 years who underwent corrective surgeries for EA from January 2009 to November 2021. PMV was defined as postoperative mechanical ventilation time longer than 24 hours. Through multivariable logistic regression, we identified and integrated the risk factors to develop a simple-to-use nomogram of PMV for EA children and internally validated it by bootstrapping. The calibration and discriminative ability of the nomogram were determined by calibration curve, Hosmer-Lemeshow goodness-of-fit test and receiver operating characteristic (ROC) curve.

RESULTS

Two hundred seventeen children were included in our study of which 44 (20.3%) were in the PMV group. After multivariable regression, we obtained five risk factors of PMV. The odds ratios and 95% confidence intervals (CI) were as follows: preoperative blood oxygen saturation, 0.876(0.805,0.953); cardiothoracic ratio, 3.007(1.107,8.169); Carpentier type, 4.644(2.065,10.445); cardiopulmonary bypass time, 1.014(1.005,1.023) and postoperative central venous pressure, 1.166(1.016,1.339). We integrated the five risk factors into a nomogram to predict the risk of PMV. The area under ROC curve of nomogram was 0.805 (95% CI, 0.725,0.885) and it also provided a good discriminative information with the corresponding Hosmer-Lemeshow p values > 0.05.

CONCLUSIONS

We developed a nomogram by integrating five independent risk factors. The nomogram is a practical tool to early identify children at high-risk for PMV after EA corrective surgery.

Improving respiratory outcomes after pediatric cardiac surgery: New uses for nitric oxide

BACKGROUND

This month's issue of Journal of Cardiac Surgery features a retrospective study on the effect of combining inhaled nitric oxide with high frequency oscillator ventilation to rescue infants who have failed conventional ventilation after congenital heart surgery.

AIMS

This commentary aims to place that study within the context of available published literature on the topic.

MATERIALS AND METHODS

The PubMed database was queried for all English-language entries between 1995 and 2021 with the terms nitric oxide, congenital heart disease, oscillator, and respiratory failure. The results were then assessed for relevance and impact by the author.

RESULTS

From these results, 15 articles were selected for use in this review. The cost of prolonged mechanical ventilation is described. The use of nitric oxide has been used to improve outcomes in hypoxic respiratory failure. High-frequency oscillator ventilation has also been studied in pediatric patients with ARDS. To date, no studies have been published showing the benefit of combining these two modalities in pediatric cardiac surgical patients.

DISCUSSION

The results of this month's study on nitric oxide and high frequency oscillator ventilation are placed in the context of current literature and suggestions for further study are presented.

CONCLUSION

Pediatric patients with hypoxic respiratory failure following congenital heart surgery have a new treatment strategy that appears effective. Further studies to confirm this should be undertaken.

Relationship Between Cardiovascular Disease Pathology and Fatal Opioid and Other Sedative Overdose: A Post-Mortem Investigation and Pilot Study

Introduction: In 2019, Scotland reported the highest number of drug deaths amongst EU countries. Of the 1,264 drug deaths reported in 2019, 94% were related to polysedative use. Studies have proposed a relationship between opioid use and cardiovascular disease. Furthermore, the concomitant use of sedatives and opioids has been associated with lethal cardiopulmonary events. However, evidence is still limited for the relationship between polysedative use and cardiovascular diseases. Thus, the present study aimed to investigate the association between polysedative use and the underlying cardiovascular pathologies in drug deaths.

Methods: This study consisted of a post-mortem investigation of 436 drug deaths. Data extracted from post-mortem reports included socio-demographic characteristics (e.g., gender, age), cardiovascular pathologies (e.g., atherosclerosis, atheroma, and inflammation), in addition to the presence of opioids (e.g. methadone, heroin) and other substances (e.g., alcohol, benzodiazepine) in the blood of the deceased. Stepwise multiple regression models were employed to identify which substances predicted cardiovascular pathologies.

Results: The presence of opioids, benzodiazepines, and alcohol in the blood of the deceased predicted overall cardiovascular disease (CVD) severity [R2 = 0.33, F (5, 430) = 39.64, p < 0.0001; adjusted R2 = 0.32, f2 = 0.49]. Positive Beta coefficients may indicate an exacerbation of CVD (B = 0.48 95% CI = 0.25, 0.70) due to the presence of opioids in the blood of the deceased. Negative associations may instead indicate a relative protective effect of alcohol (B = −0.2, 95% CI = −0.41, −0.00) and benzodiazepines (B = −0.29, 95% CI = −0.48, −0.09) on CVD.

Conclusion: These findings may inform national clinical guidelines on the need to monitor individuals who abuse opioids for presence of cardiovascular disease risk factors pathologies and provide timely interventions to reduce mortality in the population.

Pro-atrial natriuretic peptide and pro-adrenomedullin before cardiac surgery in children. Can we predict the future?

INTRODUCTION AND OBJECTIVE

Pro-atrial natriuretic peptide (proANP) and pro-adrenomedullin (proADM) levels increase in acute heart failure and sepsis. After cardiac surgery, children may require increased support in the intensive care unit and may develop complications. The aim of this study was to evaluate the utility of proANP and proADM values, determined prior to cardiac surgery, for predicting the need for increased respiratory or inotropic support during the post-operative period.

METHODS

This was a prospective study in children. Biomarkers were analyzed before surgery using a single blood test. The primary endpoints were the need for greater respiratory and/or inotropic support during the post-operative period. Secondary endpoints were the relationship between these biomarkers and complications after surgery.

RESULTS

One hundred thirteen patients were included. ProANP and proADM were higher in children who required greater respiratory and inotropic support, especially proANP; for increased respiratory support, 578.9 vs. 106.6 pmol/L (p = 0.004), and for increased inotropic support, 1938 vs. 110.4 pmol/L (p = 0.002). ProANP had a greater AUC than proADM for predicting increased respiratory support after surgery: 0.791 vs. 0.724. A possible cut-off point for proANP could be ≥ 325 pmol/L (sensitivity = 66.7% and specificity = 88.8%). In the multivariate analysis, the logarithmic transformation of proANP was independently associated with the need for increased respiratory support (OR = 3.575). Patients who presented a poor outcome after cardiac surgery also had higher biomarker values (proADM, p = 0.013; proANP, p = 0.001).

CONCLUSIONS

Elevated proANP before cardiac surgery may identify which children will need more respiratory and inotropic support during the post-operative period.

An evolving anesthetic protocol fosters fast tracking in pediatric cardiac surgery: A comparison of two anesthetic techniques

Background:

The past two decades have seen rapid development of new surgical techniques for repair as well as palliation of complex congenital heart diseases. For a better patient outcome, minimal postoperative ventilation remains one of the most important endpoints of an effectual perioperative management.

Aims and Objectives:

The aim of this randomized open-label trial was to compare postoperative extubation time and intensive care unit (ICU) stay when two different anesthetic regimens, comprising of induction with ketamine and low-dose fentanyl versus high-dose fentanyl, are used, in pediatric patients undergoing corrective/palliative surgery.

Materials and Methods:

Patients with congenital cardiac defects, under 14 years of age undergoing cardiac surgery under cardiopulmonary bypass (CPB) and epidural analgesia, were enrolled into two groups – Group K (ketamine with low-dose fentanyl) and Group F (high-dose fentanyl) – over a period of 10 months, starting from January 2018. The effect of both these drugs on postoperative extubation time and ICU stay was compared using Mann–Whitney U-test.

Results:

A total of 70 patients were assessed with equal distribution in both the groups. In Group K, 32 of 35 patients were extubated in the operation room, whereas extubation time in Group F was18.1 ± 11 h. Total ICU stay in Group K and Group F was 45.2 ± 30.1 and 60.1 ± 24.5 h, respectively (P = 0.02). Systolic blood pressure was significantly higher in Group K.

Conclusion:

Ketamine along with low-dose fentanyl, when used for anesthetic induction, in comparison to high-dose fentanyl, reduces postoperative extubation time and ICU stay, in pediatric patients undergoing corrective/palliative surgery under CPB and epidural analgesia for congenital cardiac defects.

Risk stratification models for congenital heart surgery in children: Comparative single-center study

OBJECTIVE

Three scores have been proposed to stratify the risk of mortality for each cardiac surgical procedure: The RACHS-1, the Aristotle Basic Complexity (ABC), and the STS-EACTS complexity scoring model. The aim was to compare the ability to predict mortality and morbidity of the three scores applied to a specific population.

DESIGN

Retrospective, descriptive study.

SETTING

Pediatric and neonatal intensive care units in a referral hospital.

PATIENTS

Children under 18 years admitted to the intensive care unit after surgery.

INTERVENTIONS

None.

OUTCOME MEASURES

Demographic, clinical, and surgical data were assessed. Morbidity was considered as prolonged length of stay (LOS > 75 percentile), high respiratory (>72 hours of mechanical ventilation), and high hemodynamic support (inotropic support >20).

RESULTS

One thousand and thirty-seven patients were included, in which 205 were newborns (18%). The category 2 was the most frequent in the three scores: In RACHS-1, ABC, 44.9%, and STS-EACTS, 40.8%. Newborns presented significant higher categories. Children required cardiopulmonary bypass in more occasions (P < .001) but the times of bypass and aortic cross-clamp were significantly higher in newborns (P < .001 and P = .016). Thirty-two patients died (2.8%). A quarter of patients had a prolonged LOS, 17%, a high respiratory support, and 7.1%, a high hemodynamic support. RACHS-1 (AUC 0.760) and STS-EACTS (AUC 0.763) were more powerful for predicting mortality and STS-EACTS for predicting prolonged LOS (AUC 0.733) and the need for high respiratory support (AUC 0.742).

CONCLUSIONS

STS-EACTS seems to stratify better risk of mortality, prolonged LOS, and need for respiratory support after surgery.

Impact of Cardiopulmonary Bypass and Aorta Cross Clamp Time on the Length of Mechanical Ventilation after Cardiac Surgery among Children: A Saudi Arabian Experience

Aim Several factors determine the perioperative outcome besides the nature of the congenital heart defect. Prolonged mechanical ventilation (PMV) is a major factor that determines mortality, length of stay (LOS), residual disability, and other functional outcomes. We aim to determine the clinical variables predicting PMV and LOS in hospital, and specifically the impact from the duration of cardiopulmonary bypass (CPB) and aortic cross-clamp (ACC). Method We conducted a retrospective review of the medical records of 413 children consecutively admitted to the Pediatric Cardiac Intensive Care Unit (PCICU) in one year at a single center. We collected demographic information (e.g., age, gender, and weight), perioperative variables, clinical outcomes, length of mechanical ventilation, high-frequency ventilator use, and mortality. We used logistic regression to analyze the data. PMV was defined as mechanical ventilation for longer than seven days. Results A total of 410 records were included in our study. We found no statistically significant association between CPB time and mechanical ventilation days. Forty-seven children had PMV, 362 did not have PMV. We found no statistically significant association between CPB time and mechanical ventilation days after adjusting for covariates. Reanalyzing the data with PMV defined as longer than four days produced the same results. Using a regression model to assess the variables via the least absolute shrinkage and selection operator for feature selection, we found no statistically significant association between ACC time and mechanical ventilation days after adjusting for covariates. Conclusion According to our results, CPB and ACC time are not associated with PMV or prolonged hospital LOS.

Risk factors for prolonged mechanical ventilation after surgical repair of congenital heart disease. Experience from a single cardiac center

OBJECTIVES

We studied these predictors at a single cardiac center. Methods: A retrospective cohort study was carried out after obtaining approval from the institutional review board. All patients (age, 0-14 years) who underwent  congenital heart disease (CHD)  surgery from January 2014 to June 2016 were included. Prolonged mechanical ventilation (PMV)  was defined as greater than 72 hours of ventilation. Results: A total of 257 patients were included, among whom 219 (85.2%) were intubated for greater than 72 hours and 38 (14.8%) were intubated for ≥72 hours. Age (29.9 versus 11.95 years), weight (9.6 versus 5.9 kg), cross-clamp time (CCT) (53.6 versus 71.8 min), cardiopulmonary bypass time (CBP) (80.98 versus 124.36 min), length of stay in the pediatric intensive care unit (PICU) (10.4 versus 27.2 days), infection (12.8% versus 42.1%), open sternum (0.9% versus 13.2%), re-intubation (19.2% versus 39.5%), pulmonary hypertension (10.9% versus 31.6%), and impaired heart function (10.1% versus 23.7%) were associated with PMV. In terms of Risk Adjustment in Congenital Heart Surgery (RACHS) classification, only patients with RACHS 4 (18.4%) were associated with the risk for PMV. Conclusions: Age, weight, CBP, CCT, pulmonary hypertension, impaired cardiac function, and sepsis are risk factors for PMV. These factors should be considered when deciding surgery and in providing PICU care.

Predictive value of C-reactive protein and the Pediatric Risk of Mortality III Score for occurrence of postoperative ventilator-associated pneumonia in pediatric patients with congenital heart disease

IMPORTANCE

Ventilator-associated pneumonia (VAP) is one of the most common complications after cardiac surgery in children with congenital heart disease (CHD). Early prediction of the incidence of VAP is important for clinical prevention and treatment.

OBJECTIVE

To determine the value of serum C-reactive protein (CRP) levels and the Pediatric Risk of Mortality III (PRISM III) score in predicting the risk of postoperative VAP in pediatric patients with CHD.

METHODS

We performed a retrospective review of clinical data of 481 pediatric patients with CHD who were admitted to our pediatric intensive care unit. These patients received mechanical ventilation for 48 hours or longer after corrective surgery. On the basis of their clinical manifestations and laboratory results, patients were separated into two groups of those with VAP and those without VAP. CRP levels were measured and PRISM III scores were collected within 12 hours of admission to the pediatric intensive care unit. The Pearson correlation coefficient was used to evaluate the association of CRP levels and the PRISM score with the occurrence of postoperative VAP. A linear regression model was constructed to obtain a joint function and receiver operating curves were used to assess the predictive value.

RESULTS

CRP levels and the PRISM III score in the VAP group were significantly higher than those in the non-VAP group (P < 0.05). Receiver operating curves suggested that using CRP + the PRISM III score to predict the incidence of VAP after congenial heart surgery was more accurate than using either of them alone (CRP + the PRISM III score: sensitivity: 53.2%, specificity: 85.7%). When CRP + the PRISM III score was greater than 45.460, patients were more likely to have VAP.

INTERPRETATION

Although using CRP levels plus the PRISM III score to predict the incidence of VAP after congenial heart surgery is more accurate than using either of them alone, its predictive value is still limited.

Predictors and outcome of early extubation in infants postcardiac surgery: A single-center observational study

Objective

The objective of the current study was to evaluate the timing of first extubation and compare the outcome of patient extubated early with others; we also evaluated the predictors of early extubation in our cohort.

Materials and Methods

This prospective cohort study included children <1 year of age undergoing surgery for congenital heart disease. Timing of first extubation was noted, and patients were dichotomized in the group taking 6 h after completion of surgery as cutoff for early extubation. The outcome of the patients extubated early was compared with those who required prolonged ventilation. Variables were compared between the groups, and predictors of early extubation were evaluated using multivariate logistic regression analysis.

Results

One hundred and ninety-four (33.8%) patients were extubated early including 2 extubation in operating room and 406 (70.7%) were extubated within 24 h. Four (0.7%) patients died without extubation. No significant difference in mortality and reintubation was observed between groups. Patient extubated early had a significant lower incidence of sepsis (P = 0.003) and duration of Intensive Care Unit (ICU) stay (P = 0.000). Age <6 months, risk adjustment for congenital heart surgery category ≥3, cardiopulmonary bypass time ≥80 min, aortic cross-clamp time ≥ 60 min, and vasoactive-inotropic score >10 were independently associated with prolonged ventilation.

Conclusion

Early extubation in infants postcardiac surgery lowers pediatric ICU stay and sepsis without increasing the risk of mortality or reintubation. Age more than 6 months, less complex of procedure, shorter surgery time, and lower inotropic requirement are independent predictors of early extubation.

Recommendations on RBC Transfusion in Infants and Children With Acquired and Congenital Heart Disease From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with acquired and congenital heart disease developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of 38 international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

Experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations and research priorities for RBC transfusions in critically ill children. The cardiac disease subgroup included three experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA appropriateness method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Twenty-one recommendations were developed and reached agreement. For children with myocardial dysfunction and/or pulmonary hypertension, there is no evidence that transfusion greater than hemoglobin of 10 g/dL is beneficial. For children with uncorrected heart disease, we recommended maintaining hemoglobin greater than 7-9.0 g/dL depending upon their cardiopulmonary reserve. For stable children undergoing biventricular repairs, we recommend not transfusing if the hemoglobin is greater than 7.0 g/dL. For infants undergoing staged palliative procedures with stable hemodynamics, we recommend avoiding transfusions solely based upon hemoglobin, if hemoglobin is greater than 9.0 g/dL. We recommend intraoperative and postoperative blood conservation measures. There are insufficient data supporting shorter storage duration RBCs. The risks and benefits of RBC transfusions in children with cardiac disease requires further study.

CONCLUSIONS

We present RBC transfusion management recommendations for the critically ill child with cardiac disease. Clinical recommendations emphasize relevant hemoglobin thresholds, and research recommendations emphasize need for further understanding of physiologic and hemoglobin thresholds and alternatives to RBC transfusion in subpopulations lacking pediatric literature.

Influence of factor XIII activity on post-operative transfusion in congenital cardiac surgery-A retrospective analysis

Objectives

Coagulation factor XIII (FXIII) plays a key role in fibrin clot stabilization—an essential process for wound healing following cardiothoracic surgery. However, FXIII deficiency as a risk for post-operative bleeding in pediatric cardiac surgery involving cardiopulmonary bypass (CPB) for congenital heart disease (CHD) is controversially discussed. Thus, as primary outcome measures, we analyzed the association of pre-operative FXIII activity and post-operative chest tube drainage (CTD) loss with transfusion requirements post-operatively. Secondary outcomes included the influence of cyanosis and sex on transfusion.

Methods

Our retrospective analysis (2009–2010) encompassed a single center series of 76 cardio-surgical cases with CPB (0–17 years, mean age 5.61 years) that were post-operatively admitted to our pediatric intensive care unit (PICU). The observational period was 48 hours after cardiac surgery. Blood cell counts and coagulation status, including FXIII activity were routinely performed pre- and post-operatively. The administered amount of blood products and volume expanders was recorded electronically, along with the amount of CTD loss. Uni- and multivariate logistic regression analysis was performed to calculate the associations (odds ratios) of variables with post-operative transfusion needs.

Results

FXIII activities remained stable following CPB surgery. There was no association of pre- and post-operative FXIII activities and transfusion of blood products or volume expanders in the first 48 hours after surgery. Similarly, FXIII showed no association with CTD loss. Cyanosis and female sex were associated with transfusion rates.

Conclusions

Although essentially involved in wound healing and clotting after surgery, FXIII activity does not serve as a valid predictor of post-operative transfusion need.

Risk Factors for Delayed Extubation after Ventricular Septal Defect Closure: a Prospective Observational Study

Objective

The objective of our study was to determine the feasibility of early extubation and to identify the risk factors for delayed extubation in pediatric patients operated for ventricular septal defect closure.

Methods

A prospective, observational study was carried out at our Institute. This study involved consecutive 135 patients undergoing ventricular septal defect closure. Patients were extubated if feasible within six hours after surgery. Based on duration of extubation, patients were divided two groups: Group 1= extubation time ≤ 6 hours, Group 2= extubation time >6 hours.

Results

A total of 99 patients were in Group 1 and 36 patients in Group 2. Duration of ventilation was 4.4±0.9 hours in Group 1 and 25.9±24.9 hours in Group 2 (P<0.001). Univariate analysis showed that young age, low weight, low partial pressure of oxygen, trisomy 21, multiple ventricular septal defect, high vasoactive inotropic score, transient heart block and low cardiac output syndrome were associated with delayed extubation. However, regression analysis revealed that only trisomy 21 (OR: 0.248; 95%CI: 0.176-0.701; P=0.001), low cardiac output syndrome (OR: 0.291; 95%CI: 0.267-0.979; P=0.001), multiple ventricular septal defect (OR: 0.243; 95%CI: 0.147-0.606; P=0.002) and vasoactive inotropic score (OR: 0.174 95%CI: 0.002-0.062; P=0.039) are strongest predictors for delayed extubation.

Conclusion

Trisomy 21, low cardiac output syndrome, multiple ventricular septal defect and high vasoactive inotropic score are significant risk factors for delay in extubation. Age, weight, pulmonary artery hypertension, size of ventricular septal defect, aortic cross-clamp and cardiopulmonary bypass time did not affect early extubation.

Duration of Postoperative Mechanical Ventilation as a Quality Metric for Pediatric Cardiac Surgical Programs

BACKGROUND

Few metrics exist to assess quality of care at pediatric cardiac surgical programs, limiting opportunities for benchmarking and quality improvement. Postoperative duration of mechanical ventilation (POMV) may be an important quality metric because of its association with complications and resource utilization. In this study we modelled case-mix-adjusted POMV duration and explored hospital performance across POMV metrics.

METHODS

This study used the Pediatric Cardiac Critical Care Consortium clinical registry to analyze 4,739 hospitalizations from 15 hospitals (October 2013 to August 2015). All patients admitted to pediatric cardiac intensive care units after an index cardiac operation were included. We fitted a model to predict duration of POMV accounting for patient characteristics. Robust estimates of SEs were obtained using bootstrap resampling. We created performance metrics based on observed-to-expected (O/E) POMV to compare hospitals.

RESULTS

Overall, 3,108 patients (65.6%) received POMV; the remainder were extubated intraoperatively. Our model was well calibrated across groups; neonatal age had the largest effect on predicted POMV. These comparisons suggested clinically and statistically important variation in POMV duration across centers with a threefold difference observed in O/E ratios (0.6 to 1.7). We identified 1 hospital with better-than-expected and 3 hospitals with worse-than-expected performance (p < 0.05) based on the O/E ratio.

CONCLUSIONS

We developed a novel case-mix-adjusted model to predict POMV duration after congenital heart operations. We report variation across hospitals on metrics of O/E duration of POMV that may be suitable for benchmarking quality of care. Identifying high-performing centers and practices that safely limit the duration of POMV could stimulate quality improvement efforts.

Non-invasive mechanical ventilation after heart surgery in children

Background

The purpose of the study was to analyze the characteristics and evolution of non-invasive mechanical ventilation (NIV) in the postoperative period of heart surgery in children.

Methods

Retrospective observational study including all children requiring NIV after heart surgery in a single center pediatric intensive care unit (PICU) between 2001 and 2012. Demographic characteristics, ventilation parameters and outcomes were registered, comparing the first 6 years of the study with the last 6 years.

Results

935 children required invasive or non-invasive mechanical ventilation, of which 200 (21.4) received NIV. The median duration of NIV was 3 days. Mortality rate was 3.9%. The use of NIV increased from 13.2% in the first period to 29.2% in the second period (p <0.001). Continuous positive airway pressure (CPAP) was the most common modality of NIV (65.5%). The use of bilevel positive airway pressure mode (BIPAP) increased from 15% in the first period to 42.9% in the second period (p < 0.001). The nasopharyngeal tube was the most common interface (66%), but the use of nasal cannula increased from 3.3 to 41.4% in the second period (p < 0.001). NIV failed in 15% of patients. The mortality rate did not change, the duration of NIV decreased and the PICU length of stay increased throughout the study.

Conclusions

NIV is increasingly being used in the postoperative period of heart surgery in our center with an 85% success rate and is associated with a lesser need for invasive mechanical ventilation. CPAP was the most common modality and the “nasopharyngeal tube” was the most common interface in our study although, in the latter years, the use of BIPAP and nasal cannula has increased significantly.

Predictors of Early Extubation After Pediatric Cardiac Surgery: A Single-Center Prospective Observational Study

This prospective, observational, single-center study aimed to determine the perioperative predictors of early extubation (<24 h after cardiac surgery) in a cohort of children undergoing cardiac surgery. Children aged between 1 month and 18 years who were consecutively admitted to pediatric intensive care unit after cardiac surgery for congenital heart disease between January 2012 and June 2014. Ninety-nine patients were qualified for inclusion during the study period. The median duration of mechanical ventilation was 20 h (range 1-480), and 64 patients were extubated within 24 h. Four of them failed the initial attempt at extubation, and the success rate of early extubation was 60.6 %. Older patient age (p = .009), greater body weight (p = .009), absence of preoperative pulmonary hypertension (p = .044), lower RACHS-1 category (OR, 3.8; 95 % CI 1.35-10.7; p < .05), shorter cardiopulmonary bypass (p = .008) and cross-clamp (p = .022) times, lower PRISM III-24 (p < .05) and PELOD (p < .05) scores, lower inotropic score (p < .05) and vasoactive-inotropic score (p < .05), and lower number of organ failures (OR, 2.26; 95 % CI 1.30-3.92; p < .05) were associated with early extubation. Our study establishes that early extubation can be accomplished within the first 24 h after surgery in low- to medium-risk pediatric cardiac surgery patients, especially in older ones undergoing low-complexity procedures. A large prospective multiple institution trial is necessary to identify the predictors and benefits of early extubation and to facilitate defined guidelines for early extubation.

Predictors of Prolonged Mechanical Ventilation in Pediatric Patients After Cardiac Surgery for Congenital Heart Disease

Background

The duration of mechanical ventilation (MV) is one of the most important clinical factors which predict outcomes in pediatric cardiac surgery. The prolonged mechanical ventilation (PMV) following cardiac surgery is a multifactorial phenomenon and there are conflicts regarding its predictors in pediatric population between different centers.

Objectives

The current study aimed to describe PMV predictors in patients undergoing cardiac surgery for congenital heart disease in a tertiary center for pediatric cardiovascular diseases in Iran.

Patients and Methods

From May to December 2014, all pediatric patients (less than a month – 15 years old) admitted to pediatric Intensive Care Unit (PICU) after congenital heart surgeries were consecutively included. The PMV was defined as mechanical ventilation duration more than 72 hours as medium PMV and more than seven days as extended PMV. The demographic data and variables probably related to PMV were recorded during the PICU stay.

Results

A total of 300 patients, 56.7% male, were enrolled in this study. Their mean age was 32 ± 40 months .The median duration (IQR) of MV was 18 hours (8.6 - 48 hours). The incidence of PMV more than 72 hours and seven days was 20% and 10.7%, respectively. Younger age, lower weight, heart failure, higher doses of inotropes, pulmonary hypertension, respiratory infections and delayed sternal closure were independent predictors of PMV in multivariate analyses.

Conclusions

The results of this study indicated that PMV predictors could be specific for each center and a good administration program is needed for each pediatric cardiac surgery center for the preoperative management of patients undergoing congenital heart surgeries.

Surgical Quality Predicts Length of Stay in Patients with Congenital Heart Disease

Historically, the primary marker of quality for congenital cardiac surgery has been postoperative mortality. The purpose of this study was to determine whether additional markers (10 surgical metrics) independently predict length of stay (LOS), thereby providing specific targets for quality improvement. Ten metrics (unplanned ECMO, unplanned cardiac catheterization, revision of primary repair, delayed closure, mediastinitis, reexploration for bleeding, complete heart block, vocal cord paralysis, diaphragm paralysis, and change in preoperative diagnosis) were defined in 2008 and subsequently collected from 1024 consecutive index congenital cardiac cases, yielding 990 cases. Four patient characteristics and 22 case characteristics were used for risk adjustment. Univariate and multivariable analyses were used to determine independent associations between each metric and postoperative LOS. Increased LOS was independently associated with revision of the primary repair (p = 0.014), postoperative complete heart block requiring a permanent pacemaker (p = 0.001), diaphragm paralysis requiring plication (p < 0.001), and unplanned postoperative cardiac catheterization (p < 0.001). Compared with patients without each metric, LOS was 1.6 (95 % CI 1.1-2.2, p = 0.014), 1.7 (95 % CI 1.2-2.3, p = 0.001), 1.8 (95 % CI 1.4-2.3, p < 0.001), and 2.0 (95 % CI 1.7-2.4, p < 0.001) times as long, respectively. These effects equated to an additional 4.5-7.8 days in hospital, depending on the metric. The other 6 metrics were not independently associated with increased LOS. The quality of surgery during repair of congenital heart disease affects outcomes. Reducing the incidence of these 4 specific surgical metrics may significantly decrease LOS in this population.

Longer RBC storage duration is associated with increased postoperative infections in pediatric cardiac surgery

OBJECTIVES

Infants and children undergoing open heart surgery routinely require multiple RBC transfusions. Children receiving greater numbers of RBC transfusions have increased postoperative complications and mortality. Longer RBC storage age is also associated with increased morbidity and mortality in critically ill children. Whether the association of increased transfusions and worse outcomes can be ameliorated by use of fresh RBCs in pediatric cardiac surgery for congenital heart disease is unknown.

INTERVENTIONS

One hundred and twenty-eight consecutively transfused children undergoing repair or palliation of congenital heart disease with cardiopulmonary bypass who were participating in a randomized trial of washed versus standard RBC transfusions were evaluated for an association of RBC storage age and clinical outcomes. To avoid confounding with dose of transfusions and timing of infection versus timing of transfusion, a subgroup analysis of patients only transfused 1-2 units on the day of surgery was performed.

MEASUREMENTS AND MAIN RESULTS

Mortality was low (4.9%) with no association between RBC storage duration and survival. The postoperative infection rate was significantly higher in children receiving the oldest blood (25-38 d) compared with those receiving the freshest RBCs (7-15 d) (34% vs 7%; p = 0.004). Subgroup analysis of subjects receiving only 1-2 RBC transfusions on the day of surgery (n = 74) also demonstrates a greater prevalence of infections in subjects receiving the oldest RBC units (0/33 [0%] with 7- to 15-day storage; 1/21 [5%] with 16- to 24-day storage; and 4/20 [20%] with 25- to 38-day storage; p = 0.01). In multivariate analysis, RBC storage age and corticosteroid administration were the only predictors of postoperative infection. Washing the oldest RBCs (> 27 d) was associated with a higher infection rate and increased morbidity compared with unwashed RBCs.

DISCUSSION

Longer RBC storage duration was associated with increased postoperative nosocomial infections. This association may be secondary in part, to the large doses of stored RBCs transfused, from single-donor units. Washing the oldest RBCs was associated with increased morbidity, possibly from increased destruction of older, more fragile erythrocytes incurred by washing procedures. Additional studies examining the effect of RBC storage age on postoperative infection rate in pediatric cardiac surgery are warranted.

Tracheostomy in children with congenital heart disease: a national analysis of the Kids' Inpatient Database

Background. While single-institution studies reported the indications and outcomes of tracheostomy in children with congenital heart disease (CHD), no national analyses have been performed. We sought to examine the indications, performance, outcomes, and resource utilization of tracheostomy in children with CHD using a nationally representative database. Methods. We identified all children undergoing tracheostomy in the Kids' Inpatient Database 1997 through 2009, and we compared children with CHD to children without CHD. Within the CHD group, we compared children whose tracheostomy occurred in the same hospital admission as a cardiac operation to those whose tracheostomy occurred without a cardiac operation in the same admission. Results. Tracheostomy was performed in n = 2,495 children with CHD, which represents 9.6% of all tracheostomies performed in children (n = 25,928), and 3.5% of all admissions for children with CHD (n = 355,460). Over the study period, there was an increasing trend in the proportion of all tracheostomies that were done in children with CHD (p < 0.0001) and an increasing trend in the proportion of admissions for children with CHD that involved a tracheostomy (p < 0.0001). The population of children with CHD undergoing tracheostomy differed markedly in baseline characteristics, outcomes, and resource utilization. Similarly, the subgroup of children whose tracheostomy was performed in the same admission as a cardiac operation differed significantly from those whose tracheostomy was not. Conclusions. Tracheostomy is an increasingly common procedure in children with CHD despite being associated with significantly greater resource utilization and in-hospital mortality. The population of children with CHD who undergo tracheostomy differs markedly from that of children without CHD who undergo tracheostomy, and important differences are observed between children who undergo tracheostomy in the same admission as a cardiac surgical procedure and those who undergo tracheostomy in a nonsurgical admission, as well as between children with single-ventricle physiology and children with two-ventricle physiology.

Risk factors for postoperative hypoxemia in patients undergoing Stanford A aortic dissection surgery

Background

The purpose of this study is to identify the risk factors for postoperative hypoxemia in patients with Stanford A aortic dissection surgery and their relation to clinical outcomes.

Methods

Clinical records of 186 patients with postoperative hypoxemia in Stanford A aortic dissection were analyzed retrospectively. The patients were divided into two groups by postoperative oxygen fraction (PaO2/FiO2):hypoxemia group (N=92) and non-hypoxemia group (N=94).

Results

We found that the incidence of postoperative hypoxemia was 49.5%. Statistical analysis by t-test and χ2 indicated that acute onset of the aortic dissection (p=0.000), preoperative oxygen fraction (PaO2/FiO2) ≤200 mmHg(p=0.000), body mass index (p=0.008), circulatory arrest (CA) time (p=0.000) and transfusion more than 3000 ml(p=0.000) were significantly associated with postoperative hypoxemia. Multiple logistic regression analysis showed that preoperative hypoxemia, CA time and transfusion more than 3000 ml were independently associated with postoperative hypoxemia in Stanford A aortic dissection.

Conclusion

Our results suggest that postoperative hypoxemia is a common complication in patients treated by Stanford A aortic dissection surgery. Preoperative oxygen fraction lower than 200 mmHg, longer CA time and transfusion more than 3000 ml are predictors of postoperative hypoxemia in Stanford A aortic dissection.

Determinants of immediate extubation in the operating room after total thoracoscopic closure of congenital heart defects

OBJECTIVE

This study was designed to assess the factors that influence immediate extubation following totally thoracoscopic closure of congenital heart defects.

SUBJECTS AND METHODS

Clinical and operational data of 216 patients (87 males, average age 13.6 ± 10.9 years) were retrospectively analyzed. Atrial (ASD, n = 90) or ventricular septal defects (VSD, n = 126) were closed via a totally thoracoscopic approach. Ultra-fast-track anesthesia (UFTA) was used in all patients.

RESULTS

Immediate extubation in the operating room was successfully performed in 156 (72.2%) patients. A delayed extubation was completed in the intensive care unit in the remaining 60 (27.8%) patients. There was no significant difference in the age, sex, body weight, or type of congenital heart defect between the immediate and delayed extubation groups (p > 0.05). However, more patients in the delayed extubation group had severe preoperational pulmonary hypertension [8 (13.3%) vs. 4 (2.3%), p < 0.05]. The cardiopulmonary bypass time, aortic clamp time, and total duration of the surgery in the immediate extubation group were shorter than in the delayed extubation group (p < 0.05). Multivariate logistic regression analysis showed that preoperational pulmonary hypertension, duration of the surgery or cardiopulmonary bypass, and dosage of fentanyl used during the surgery were independent predictors for immediate extubation.

CONCLUSIONS

UFTA and immediate extubation in the operating room was feasible and safe in the majority of patients undergoing totally thoracoscopic closure of ASD or VSD. Preoperational pulmonary hypertension, duration of the surgery, and the dosage of fentanyl used for UFTA were the determining factors for immediate extubation.

Blood transfusion is associated with prolonged duration of mechanical ventilation in infants undergoing reparative cardiac surgery

OBJECTIVE

Perioperative transfusion has adverse effects in adults undergoing cardiac surgery. We sought to investigate whether greater use of blood and blood products might be an independent predictor of prolonged postoperative recovery, indicated by duration of mechanical ventilation (DMV), after reparative infant heart surgery.

DESIGN

Secondary analysis of prospectively collected data from two randomized trials of hematocrit strategy during cardiopulmonary bypass in infant heart surgery to explore the association of DMV with perioperative transfusion and other variables.

SETTING

Tertiary pediatric hospital.

PATIENTS

Two hundred seventy infants undergoing two ventricle corrective cardiac surgery without aortic arch reconstruction.

MEASUREMENTS AND MAIN RESULTS

In univariable analyses, longer DMV was associated with younger age and lower weight at surgery, diagnostic group, and higher intraoperative and postoperative blood product transfusion (each p < .001). In multivariable proportional hazard regression, longer total support time and greater intraoperative and early postoperative blood products per kg were the strongest predictors of longer DMV. Patients in the highest tertile of intraoperative blood products per kg had an instantaneous risk of being extubated approximately half that of patients in the lowest tertile (hazard ratio, 0.51; 95% confidence interval, 0.35, 0.73). Patients who received any blood products on postoperative day 1, compared with those who did not, had a hazard ratio for extubation of 0.65 (95% confidence interval, 0.50, 0.85).

CONCLUSIONS

In this exploratory secondary analysis of infants undergoing two ventricular repair of congenital heart disease without aortic arch obstruction, greater intraoperative and early postoperative blood transfusion emerged as potential important risk factors for longer DMV. Future prospective clinical trials are needed to determine whether reduction in blood product administration hastens postoperative recovery after infant heart surgery.

Increased postoperative and respiratory complications in patients with congenital heart disease associated with heterotaxy

OBJECTIVE

Patients with heterotaxy and complex congenital heart disease underwent cardiac surgery with high mortality and morbidity. Recent studies have revealed an association among heterotaxy, congenital heart disease, and primary ciliary dyskinesia. We undertook a retrospective review of patients undergoing cardiac surgery at Children's National Medical Center between 2004 and 2008 to explore the hypothesis that there is increased mortality and respiratory complications in heterotaxy patients.

METHODS

Retrospective review was performed on postsurgical outcomes of 87 patients with heterotaxy and congenital heart disease exhibiting the full spectrum of situs abnormalities associated with heterotaxy. As controls patients, 634 cardiac surgical patients with congenital heart disease, but without laterality defects, were selected, and surgical complexities were similar with a median Risk Adjustment in Congenital Heart Surgery-1 score of 3.0 for both groups.

RESULTS

We found the mean length of postoperative hospital stay (17 vs 11 days) and mechanical ventilation (11 vs 4 days) were significantly increased in the heterotaxy patients. Also elevated were rates of tracheostomies (6.9% vs 1.6%; odds ratio, 4.6), extracorporeal membrane oxygenation support (12.6% vs 4.9%: odds ratio, 2.8), prolonged ventilatory courses (23% vs 12.3%; odds ratio, 2.1) and postsurgical deaths (16.1% vs 4.7%; odds ratio, 3.9).

CONCLUSIONS

Our findings show heterotaxy patients had more postsurgical events with increased postsurgical mortality and risk for respiratory complications as compared to control patients with similar Risk Adjustment in Congenital Heart Surgery-1 surgical complexity scores. We speculate that increased respiratory complications maybe due to ciliary dysfunction. Further studies are needed to explore the basis for the increased surgical risks for heterotaxy patients undergoing cardiac surgery.

Higher pulmonary dead space may predict prolonged mechanical ventilation after cardiac surgery

Children undergoing congenital heart surgery are at risk for prolonged mechanical ventilation and length of hospital stay. We investigated the prognostic value of pulmonary dead space fraction as a non-invasive, physiologic marker in this population. In a prospective, cross-sectional study, we measured pulmonary dead space fraction in 52 intubated, pediatric patients within 24 hr postoperative from congenital heart surgery. Measurements were obtained with a bedside, non-invasive cardiac output (NICO) monitor (Respironics Novametrix, Inc., Wallingford, CT). Median pulmonary dead space fraction was 0.46 (25-75% IQR 0.34-0.55). Pulmonary dead space fraction significantly correlated with duration of mechanical ventilation and length of hospital stay in the entire cohort (r(s) = 0.51, P = 0.0002; r(s) = 0.51, P = 0.0002) and in the subset of patients without residual intracardiac shunting (r(s) = 0.45, P = 0.008; r(s) = 0.49, P = 0.004). In a multivariable logistic regression model, pulmonary dead space fraction remained an independent predictor for prolonged mechanical ventilation in the presence of cardiopulmonary bypass time and ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (OR 2.2; 95% CI 1.14-4.38; P = 0.02). The area under the receiver operator characteristic curve for this model was 0.91. Elevated pulmonary dead space fraction is associated with prolonged mechanical ventilation and hospital stay in pediatric patients who undergo surgery for congenital heart disease and has additive predictive value in identifying those at risk for longer duration of mechanical ventilation. Pulmonary dead space may be a useful prognostic tool for clinicians in patients who undergo congenital heart surgery.