Diuretic response after neonatal cardiac surgery: a report from the NEPHRON collaborative

BACKGROUND

Multicenter early diuretic response (DR) analysis of single furosemide dosing following neonatal cardiac surgery is lacking to inform whether early DR predicts adverse clinical outcomes.

METHODS

We performed a retrospective cohort study utilizing data from the NEPHRON registry. Random forest machine learning generated receiver operating characteristic-area under the curve (ROC-AUC) and odds ratios for mechanical ventilation (MV) and respiratory support (RS). Prolonged MV and RS were defined using ≥ 90th percentile of observed/expected ratios. Secondary outcomes were prolonged CICU and hospital length of stay (LOS) and kidney failure (stage III acute kidney injury (AKI), peritoneal dialysis, and/or continuous kidney replacement therapy on postoperative day three) assessed using covariate-adjusted ROC-AUC curves.

RESULTS

A total of 782 children were included. Cumulative urine output (UOP) metrics were lower in prolonged MV and RS patients, but DR poorly predicted prolonged MV (highest AUC 0.611, OR 0.98, sensitivity 0.67, specificity 0.53, p = 0.006, 95% OR CI 0.96-0.99 for cumulative 6-h UOP) and RS (highest AUC 0.674, OR 0.94, sensitivity 0.75, specificity 0.54, p < 0.001, 95% CI 0.91-0.97 UOP between 3 and 6 h). Secondary outcome results were similar. DR had fair discrimination for kidney failure (AUC 0.703, OR 0.94, sensitivity 0.63, specificity 0.71, 95% OR CI 0.91-0.98, p < 0.001, cumulative 6-h UOP).

CONCLUSIONS

Early DR poorly discriminated patients with prolonged MV, RS, and LOS in this cohort, though it may identify severe postoperative AKI phenotype. Future work is warranted to determine if early DR or late postoperative DR later, in combination with other AKI metrics, may identify a higher-risk phenotype.

Cardiac Surgery-Associated Acute Kidney Injury in Neonates Undergoing the Norwood Operation: Retrospective Analysis of the Multicenter Neonatal and Pediatric Heart and Renal Outcomes Network Dataset, 2015-2018

OBJECTIVES

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with adverse outcomes. Single-center studies suggest that the prevalence of CS-AKI is high after the Norwood procedure, or stage 1 palliation (S1P), but multicenter data are lacking.

DESIGN

A secondary analysis of the Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) multicenter cohort who underwent S1P. Using neonatal modification of Kidney Disease Improving Global Outcomes (KDIGO) criteria, perioperative associations between CS-AKI with morbidity and mortality were examined. Sensitivity analysis, with the exclusion of prophylactic peritoneal dialysis (PD) patients, was performed.

SETTING

Twenty-two hospitals participating in the Pediatric Cardiac Critical Care Consortium (PC 4 ) and contributing to NEPHRON.

PATIENTS

Three hundred forty-seven neonates (< 30 d old) with S1P managed between September 2015 and January 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 347 patients, CS-AKI occurred in 231 (67%). The maximum stages were as follows: stage 1, in 141 of 347 (41%); stage 2, in 51 of 347 (15%); and stage 3, in 39 of 347 (11%). Severe CS-AKI (stages 2 and 3) peaked on the first postoperative day. In multivariable analysis, preoperative feeding was associated with lower odds of CS-AKI (odds ratio [OR] 0.48; 95% CI, 0.27-0.86), whereas prophylactic PD was associated with greater odds of severe CS-AKI (OR 3.67 [95% CI, 1.88-7.19]). We failed to identify an association between prophylactic PD and increased creatinine (OR 1.85 [95% CI, 0.82-4.14]) but cannot exclude the possibility of a four-fold increase in odds. Hospital mortality was 5.5% ( n = 19). After adjusting for risk covariates and center effect, severe CS-AKI was associated with greater odds of hospital mortality (OR 3.67 [95% CI, 1.11-12.16]). We failed to find associations between severe CS-AKI and respiratory support or length of stay. The sensitivity analysis using PD failed to show associations between severe CS-AKI and outcome.

CONCLUSIONS

KDIGO-defined CS-AKI occurred frequently and early postoperatively in this 2015-2018 multicenter PC 4 /NEPHRON cohort of neonates after S1P. We failed to identify associations between resource utilization and CS-AKI, but there was an association between severe CS-AKI and greater odds of mortality in this high-risk cohort. Improving the precision for defining clinically relevant neonatal CS-AKI remains a priority.

Persistent acute kidney injury and fluid accumulation with outcomes after the Norwood procedure: report from NEPHRON

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common, but its impact on clinical outcomes is variable. Parsing AKI into sub-phenotype(s) and integrating pathologic positive cumulative fluid balance (CFB) may better inform prognosis. We sought to determine whether durational sub-phenotyping of CS-AKI with CFB strengthens association with outcomes among neonates undergoing the Norwood procedure.

METHODS

Multicenter, retrospective cohort study from the Neonatal and Pediatric Heart and Renal Outcomes Network. Transient CS-AKI: present only on post-operative day (POD) 1 and/or 2; persistent CS-AKI: continued after POD 2. CFB was evaluated per day and peak CFB during the first 7 postoperative days. Primary and secondary outcomes were mortality, respiratory support-free and hospital-free days (at 28, 60 days, respectively). The primary predictor was persistent CS-AKI, defined by modified neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

CS-AKI occurred in 59% (205/347) neonates: 36.6% (127/347) transient and 22.5% (78/347) persistent; CFB > 10% occurred in 18.7% (65/347). Patients with either persistent CS-AKI or peak CFB > 10% had higher mortality. Combined persistent CS-AKI with peak CFB > 10% (n = 21) associated with increased mortality (aOR: 7.8, 95% CI: 1.4, 45.5; p = 0.02), decreased respiratory support-free (predicted mean 12 vs. 19; p < 0.001) and hospital-free days (17 vs. 29; p = 0.048) compared to those with neither.

CONCLUSIONS

The combination of persistent CS-AKI and peak CFB > 10% after the Norwood procedure is associated with mortality and hospital resource utilization. Prospective studies targeting intra- and postoperative CS-AKI risk factors and reducing CFB have the potential to improve outcomes.

Mechanical Ventilation and Outcomes of Children Who Undergo Ventricular Assist Device Placement: 2014-2020 Linked Analysis From the Advanced Cardiac Therapies Improving Outcomes Network and Pediatric Cardiac Critical Care Consortium Registries

OBJECTIVES

Placement of a ventricular assist device (VAD) improves outcomes in children with advanced heart failure, but adverse events remain important consequences. Preoperative mechanical ventilation (MV) increases mortality, but it is unknown what impact prolonged postoperative MV has.

DESIGN

Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and Pediatric Cardiac Critical Care Consortium (PC4) registries were used to identify and link children with initial VAD placement admitted to the cardiac ICU (CICU) from August 2014 to July 2020. Demographics, cardiac diagnosis, preoperative and postoperative CICU courses, and outcomes were compiled. Univariable and multivariable statistics assessed association of patient factors with prolonged postoperative MV. Multivariable logistic regression sought independent associations with outcomes.

SETTING

Thirty-five pediatric CICUs across the United States and Canada.

PATIENTS

Children on VADs included in both registries.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred forty-eight ACTION subjects were linked to a matching patient in PC4. Median (interquartile) age 7.7 years (1.5-15.5 yr), weight 21.3 kg (9.1-58 kg), and 56% male. Primary diagnosis was congenital heart disease (CHD) in 35%. Pre-VAD explanatory variables independently associated with prolonged postoperative MV included: age (incidence rate ratio [IRR], 0.95; 95% CI, 0.93-0.96; p < 0.01); preoperative MV within 48 hours (IRR, 2.76; 95% CI, 1.59-4.79; p < 0.01), 2-7 days (IRR, 1.82; 95% CI, 1.15-2.89; p = 0.011), and greater than 7 days before VAD implant (IRR, 2.35; 95% CI, 1.62-3.4; p < 0.01); and CHD (IRR, 1.96; 95% CI, 1.48-2.59; p < 0.01). Each additional day of postoperative MV was associated with greater odds of mortality (odds ratio [OR], 1.09 per day; p < 0.01) in the full cohort. We identified an associated greater odds of mortality in the 102 patients with intracorporeal devices (OR, 1.24; 95% CI, 1.04-1.48; p = 0.014), but not paracorporeal devices (77 patients; OR, 1.04; 95% CI, 0.99-1.09; p = 0.115).

CONCLUSIONS

Prolonged MV after VAD placement is associated with greater odds of mortality in intracorporeal devices, which may indicate inadequacy of cardiopulmonary support in this group. This linkage provides a platform for future analyses in this population.

Achieving Consensus: Severity-Graded Definitions of Fontan-Associated Complications to Characterize Fontan Circulatory Failure

BACKGROUND

Fontan physiology leads to chronic changes in other organ systems that may affect long-term survival and the success of heart transplantation. Inadequate assessment and treatment of the extra-cardiac effects of Fontan may contribute to poor outcomes. Severity-graded/ordinal consensus definitions of Fontan complications are lacking, which limits understanding of how Fontan-specific morbidity affects patients' outcomes.

METHODS AND RESULTS

A panel of Fontan patient and physiology experts, including pediatric, adult congenital, heart failure, and critical-care cardiology as well as pediatric nephrology, hepatology and psychology, convened to develop definitions of Fontan complications. Definitions were created by using a severity-graded ordinal scale: grade 1, mild; grade 2, moderate; grade 3, severe; grade 4, disabling or life threatening. Following definition creation, a second panel of 21 experts in Fontan circulatory failure used a modified Delphi methodology to modify and vote on definitions until consensus (> 90% agreement without recommended further modification) was reached on final definitions. After 3 rounds of modifications and voting, consensus agreement was achieved on all Fontan-specific definitions. The defined complications and morbidities of Fontan include: anatomic Fontan pathway obstruction, cyanosis, systemic venous abnormalities resulting from venous insufficiency, atrial arrhythmia, ventricular arrhythmia, bradycardia, chronic pleural effusions, chronic ascites, protein-losing enteropathy, plastic bronchitis, hemoptysis and pulmonary hemorrhage, sleep apnea, Fontan-associated liver disease, portal and hepatic variceal disease, acute kidney injury affecting clinical treatment, polycythemia, thrombotic disease, recurrent or severe bacterial infection, skin atrophy, adrenal insufficiency, physical impact of previous stroke, mood/behavior disorder, and neurodevelopmental disorder.

CONCLUSION

Consensus and severity-graded definitions of Fontan-specific cardiac and extra-cardiac complications were achieved and are available for use in research. They will allow future robust analyses of Fontan patient outcomes.

Neonatal Chylothorax and Early Fluid Overload After Cardiac Surgery: Retrospective Analysis of the Neonatal and Pediatric Heart and Renal Outcomes Network Registry (2015-2018)

OBJECTIVES

To evaluate the association between postoperative cumulative fluid balance (FB) and development of chylothorax in neonates after cardiac surgery.

DESIGN

Multicenter, retrospective cohort identified within the Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) Registry.

SETTING

Twenty-two hospitals were involved with NEPHRON, from September 2015 to January 2018.

PATIENTS

Neonates (< 30 d old) undergoing index cardiac operation with or without cardiopulmonary bypass (CPB) entered into the NEPHRON Registry. Postoperative chylothorax was defined in the Pediatric Cardiac Critical Care Consortium as lymphatic fluid in the pleural space secondary to a leak from the thoracic duct or its branches.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 2240 NEPHRON patients, 4% ( n = 89) were treated for chylothorax during postoperative day (POD) 2-21. Median (interquartile range [IQR]) time to diagnosis was 8 (IQR 6, 12) days. Of patients treated for chylothorax, 81 of 89 (91%) had CPB and 68 of 89 (76%) had Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery Congenital Heart Surgery 4-5 operations. On bivariate analysis, chylothorax patients had higher POD 1 FB (3.2 vs. 1.1%, p = 0.014), higher cumulative POD 2 FB (1.5 vs. -1.5%, p < 0.001), achieved negative daily FB by POD 1 less often (69% vs. 79%, p = 0.039), and had lower POD 1 urine output (1.9 vs. 3. 2 mL/kg/day, p ≤ 0.001) than those without chylothorax. We failed to identify an association between presence or absence of chylothorax and peak FB (5.2 vs. 4.9%, p = 0.9). Multivariable analysis shows that higher cumulative FB on POD 2 was associated with greater odds (odds ratio [OR], 95% CI) of chylothorax development (OR 1.5 [95% CI, 1.1-2.2]). Further multivariable analysis shows that chylothorax was independently associated with greater odds of longer durations of mechanical ventilation (OR 5.5 [95% CI, 3.7-8.0]), respiratory support (OR 4.3 [95% CI, 2.9-6.2]), use of inotropic support (OR 2.9 [95% CI, 2.0-4.3]), and longer hospital length of stay (OR 3.7 [95% CI, 2.5-5.4]).

CONCLUSIONS

Chylothorax after neonatal cardiac surgery for congenital heart disease (CHD) is independently associated with greater odds of longer duration of cardiorespiratory support and hospitalization. Higher early (POD 2) cumulative FB is associated with greater odds of chylothorax. Contemporary, prospective studies are needed to assess whether early fluid mitigation strategies decrease postoperative chylothorax development.

Factors Associated With Attendance for Cardiac Neurodevelopmental Evaluation

BACKGROUND AND OBJECTIVES

Neurodevelopmental evaluation of toddlers with complex congenital heart disease is recommended but reported frequency is low. Data on barriers to attending neurodevelopmental follow-up are limited. This study aims to estimate the attendance rate for a toddler neurodevelopmental evaluation in a contemporary multicenter cohort and to assess patient and center level factors associated with attending this evaluation.

METHODS

This is a retrospective cohort study of children born between September 2017 and September 2018 who underwent cardiopulmonary bypass in their first year of life at a center contributing data to the Cardiac Neurodevelopmental Outcome Collaborative and Pediatric Cardiac Critical Care Consortium clinical registries. The primary outcome was attendance for a neurodevelopmental evaluation between 11 and 30 months of age. Sociodemographic and medical characteristics and center factors specific to neurodevelopmental program design were considered as predictors for attendance.

RESULTS

Among 2385 patients eligible from 16 cardiac centers, the attendance rate was 29.0% (692 of 2385), with a range of 7.8% to 54.3% across individual centers. In multivariable logistic regression models, hospital-initiated (versus family-initiated) scheduling for neurodevelopmental evaluation had the largest odds ratio in predicting attendance (odds ratio = 4.24, 95% confidence interval, 2.74-6.55). Other predictors of attendance included antenatal diagnosis, absence of Trisomy 21, higher Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category, longer postoperative length of stay, private insurance, and residing a shorter distance from the hospital.

CONCLUSIONS

Attendance rates reflect some improvement but remain low. Changes to program infrastructure and design and minimizing barriers affecting access to care are essential components for improving neurodevelopmental care and outcomes for children with congenital heart disease.

Early postoperative weight-based fluid overload is associated with worse outcomes after neonatal cardiac surgery

OBJECTIVES

Evaluate the association of postoperative day (POD) 2 weight-based fluid balance (FB-W) > 10% with outcomes after neonatal cardiac surgery.

METHODS

Retrospective cohort study of 22 hospitals in the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) registry from September 2015 to January 2018. Of 2240 eligible patients, 997 neonates (cardiopulmonary bypass (CPB) n = 658, non-CPB n = 339) were weighed on POD2 and included.

RESULTS

Forty-five percent (n = 444) of patients had FB-W > 10%. Patients with POD2 FB-W > 10% had higher acuity of illness and worse outcomes. Hospital mortality was 2.8% (n = 28) and not independently associated with POD2 FB-W > 10% (OR 1.04; 95% CI 0.29-3.68). POD2 FB-W > 10% was associated with all utilization outcomes, including duration of mechanical ventilation (multiplicative rate of 1.19; 95% CI 1.04-1.36), respiratory support (1.28; 95% CI 1.07-1.54), inotropic support (1.38; 95% CI 1.10-1.73), and postoperative hospital length of stay (LOS 1.15; 95% CI 1.03-1.27). In secondary analyses, POD2 FB-W as a continuous variable demonstrated association with prolonged durations of mechanical ventilation (OR 1.04; 95% CI 1.02-1.06], respiratory support (1.03; 95% CI 1.01-1.05), inotropic support (1.03; 95% CI 1.00-1.05), and postoperative hospital LOS (1.02; 95% CI 1.00-1.04). POD2 intake-output based fluid balance (FB-IO) was not associated with any outcome.

CONCLUSIONS

POD2 weight-based fluid balance > 10% occurs frequently after neonatal cardiac surgery and is associated with longer cardiorespiratory support and postoperative hospital LOS. However, POD2 FB-IO was not associated with clinical outcomes. Mitigating early postoperative fluid accumulation may improve outcomes but requires safely weighing neonates in the early postoperative period. A higher resolution version of the Graphical abstract is available as Supplementary information.

Assessment of fluid balance after neonatal cardiac surgery: a description of intake/output vs. weight-based methods

BACKGROUND

Fluid overload associates with poor outcomes after neonatal cardiac surgery, but consensus does not exist for the most clinically relevant method of measuring fluid balance (FB). While weight change-based FB (FB-W) is standard in neonatal intensive care units, weighing infants after cardiac surgery may be challenging. We aimed to identify characteristics associated with obtaining weights and to understand how intake/output-based FB (FB-IO) and FB-W compare in the early postoperative period in this population.

METHODS

Observational retrospective study of 2235 neonates undergoing cardiac surgery from 22 hospitals comprising the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) database.

RESULTS

Forty-five percent (n = 998) of patients were weighed on postoperative day (POD) 2, varying from 2 to 98% among centers. Odds of being weighed were lower for STAT categories 4 and 5 (OR 0.72; 95% CI 0.53-0.98), cardiopulmonary bypass (0.59; 0.42-0.83), delayed sternal closure (0.27; 0.19-0.38), prophylactic peritoneal dialysis use (0.58; 0.34-0.99), and mechanical ventilation on POD 2 (0.23; 0.16-0.33). Correlation between FB-IO and FB-W was weak for every POD 1-6 and within the entire cohort (correlation coefficient 0.15; 95% CI 0.12-0.17). FB-W measured higher than paired FB-IO (mean bias 12.5%; 95% CI 11.6-13.4%) with wide 95% limits of agreement (- 15.4-40.4%).

CONCLUSIONS

Weighing neonates early after cardiac surgery is uncommon, with significant practice variation among centers. Patients with increased severity of illness are less likely to be weighed. FB-W and FB-IO have weak correlation, and further study is needed to determine which cumulative FB metric most associates with adverse outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Fluid Accumulation After Neonatal Congenital Cardiac Operation: Clinical Implications and Outcomes

BACKGROUND

This study was conducted to determine the association between fluid balance metrics and mortality and other postoperative outcomes after neonatal cardiac operation in a contemporary multicenter cohort.

METHODS

This was an observational cohort study across 22 hospitals in neonates (≤30 days) undergoing cardiac operation. We explored overall percentage fluid overload, postoperative day 1 percentage fluid overload, peak percentage fluid overload, and time to first negative daily fluid balance. The primary outcome was in-hospital mortality. Secondary outcomes included postoperative duration of mechanical ventilation and intensive care unit (ICU) and hospital length of stay. Multivariable logistic or negative binomial regression was used to determine independent associations between fluid overload variables and each outcome.

RESULTS

The cohort included 2223 patients. In-hospital mortality was 3.9% (n = 87). Overall median peak percentage fluid overload was 4.9% (interquartile range, 0.4%-10.5%). Peak percentage fluid overload and postoperative day 1 percentage fluid overload were not associated with primary or secondary outcomes. Hospital resource utilization increased on each successive day of not achieving a first negative daily fluid balance and was characterized by longer duration of mechanical ventilation (incidence rate ratio, 1.11; 95% CI, 1.08-1.14), ICU length of stay (incidence rate ratio, 1.08; 95% CI, 1.03-1.12), and hospital length of stay (incidence rate ratio, 1.09; 95% CI, 1.05-1.13).

CONCLUSIONS

Time to first negative daily fluid balance, but not percentage fluid overload, is associated with improved postoperative outcomes in neonates after cardiac operation. Specific treatments to achieve an early negative fluid balance may decrease postoperative care durations.

Epidemiology of neonatal acute kidney injury after cardiac surgery without cardiopulmonary bypass

BACKGROUND

The purpose of this Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) study was to describe the epidemiology and outcomes of CS-AKI after cardiac surgery without cardiopulmonary bypass (non-CPB).

METHODS

We performed a retrospective study of neonates (≤30 days) who underwent non-CPB cardiac surgery at 22 centers affiliated with the Pediatric Cardiac Critical Care Consortium. CS-AKI was defined using the modified Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine (SCr) and urine output criteria from postoperative day (POD) 0-6. CS-AKI by SCr was further subclassified into transient (resolved by POD3) and persistent/late (≥3 days). Multivariable regression analyses were used to determine risk factors for CS-AKI, and associations with outcomes of ventilation hours and cardiac intensive care unit length of stay (LOS).

RESULTS

582 neonates [median age at surgery: 9 days (IQR:5-15 days), 25% functional single ventricle] were included. CS-AKI occurred in 38.3%: rate and severity varied across centers. Aggregate daily CS-AKI prevalence peaked on POD1 (17.1%). No stage of CS-AKI was associated with ventilation hours or LOS. Persistent/late CS-AKI occurred in 48 (8%). Prostaglandin use and single ventricle surgery were associated with persistent/late CS-AKI. Higher baseline SCr, but not persistent/late CS-AKI was associated with longer ventilation duration and ICU LOS after adjusting for confounders.

CONCLUSIONS

KDIGO-defined CS-AKI occurred commonly in neonates undergoing non-CPB cardiac surgery. However, most CS-AKI was transient, and no CS-AKI classification was associated with worse outcomes. Further work is needed to determine the CS-AKI definition that best associates with outcomes in this cohort.

Epidemiology of Acute Kidney Injury After Neonatal Cardiac Surgery: A Report From the Multicenter Neonatal and Pediatric Heart and Renal Outcomes Network

OBJECTIVES

Cardiac surgery-associated acute kidney injury occurs commonly following congenital heart surgery and is associated with adverse outcomes. This study represents the first multicenter study of neonatal cardiac surgery-associated acute kidney injury. We aimed to describe the epidemiology, including perioperative predictors and associated outcomes of this important complication.

DESIGN

This Neonatal and Pediatric Heart and Renal Outcomes Network study is a multicenter, retrospective cohort study of consecutive neonates less than 30 days. Neonatal modification of The Kidney Disease Improving Global Outcomes criteria was used. Associations between cardiac surgery-associated acute kidney injury stage and outcomes (mortality, length of stay, and duration of mechanical ventilation) were assessed through multivariable regression.

SETTING

Twenty-two hospitals participating in Pediatric Cardiac Critical Care Consortium.

PATIENTS

Twenty-two-thousand forty neonates who underwent major cardiac surgery from September 2015 to January 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cardiac surgery-associated acute kidney injury occurred in 1,207 patients (53.8%); 983 of 1,657 in cardiopulmonary bypass patients (59.3%) and 224 of 583 in noncardiopulmonary bypass patients (38.4%). Seven-hundred two (31.3%) had maximum stage 1, 302 (13.5%) stage 2, 203 (9.1%) stage 3; prevalence of cardiac surgery-associated acute kidney injury peaked on postoperative day 1. Cardiac surgery-associated acute kidney injury rates varied greatly (27-86%) across institutions. Preoperative enteral feeding (odds ratio = 0.68; 0.52-0.9) and open sternum (odds ratio = 0.76; 0.61-0.96) were associated with less cardiac surgery-associated acute kidney injury; cardiopulmonary bypass was associated with increased cardiac surgery-associated acute kidney injury (odds ratio = 1.53; 1.01-2.32). Duration of cardiopulmonary bypass was not associated with cardiac surgery-associated acute kidney injury in the cardiopulmonary bypass cohort. Stage 3 cardiac surgery-associated acute kidney injury was independently associated with hospital mortality (odds ratio = 2.44; 1.3-4.61). No cardiac surgery-associated acute kidney injury stage was associated with duration of mechanical ventilation or length of stay.

CONCLUSIONS

Cardiac surgery-associated acute kidney injury occurs frequently after neonatal cardiac surgery in both cardiopulmonary bypass and noncardiopulmonary bypass patients. Rates vary significantly across hospitals. Only stage 3 cardiac surgery-associated acute kidney injury is associated with mortality. Cardiac surgery-associated acute kidney injury was not associated with any other outcomes. Kidney Disease Improving Global Outcomes criteria may not precisely define a clinically meaningful renal injury phenotype in this population.

Mortality from Pulmonary Hypertension in the Pediatric Cardiac ICU

Rationale: Patients with pulmonary hypertension (PH) admitted to pediatric cardiac ICUs are at high risk of mortality. Objectives: To identify factors associated with mortality in cardiac critical care admissions with PH. Methods: We evaluated medical admissions with PH to Pediatric Cardiac Critical Care Consortium institutions over 5 years. PH was standardly defined in the clinical registry by diagnosis and/or receipt of intensive care-level pulmonary vasodilator therapy. Multivariable logistic regression identified independent associations with mortality. Measurements and Main Results: We analyzed 2,602 admissions; mortality was 10% versus 3.9% for all other medical admissions. Covariates most strongly associated with mortality included invasive ventilation (adjusted odds ratio, 44.8; 95% confidence interval, 6.2-323), noninvasive ventilation (19.7; 2.8-140), cardiopulmonary resuscitation (8.9; 5.6-14.1), and vasoactive infusions (4.8; 2.6-8.8). Patients receiving both invasive ventilation and vasoactive infusions on admission Days 1 and 2 had an observed mortality rate of 29.2% and 28.6%, respectively, compared with <5% for those not receiving either. Vasoactive infusions emerged as the dominant early risk factor for mortality, increasing the absolute risk of mortality on average by 6.4% when present on admission Day 2. Conclusions: Patients with PH admitted to pediatric cardiac critical care units have high mortality rates. Those receiving invasive ventilation and vasoactive infusions on Day 1 or Day 2 had an observed mortality rate that was more than fivefold greater than that of those who did not. These data highlight the illness severity of patients with PH in this setting and could help inform conversations with families regarding the prognosis.

[Recommendations for sedation during flexible bronchoscopy]

Flexible bronchoscopy is a standard examination today and is conducted not only in nearly every hospital but also in privately owned practices. The vast majority of patients want sedation for this examination. Such a procedure is nearly always necessary in complex and interventional procedures, irrespective of the patient's wish. The recommendation at hand to use sedation measures for flexible bronchoscopy is based on the results of numerous clinical studies and also takes account of individual experiences in this area. The structural and procedural requirements and the requirements for staff training are defined and should describe the minimum standard when it comes to conducting a bronchoscopy under sedation. Furthermore the drugs recommended for sedation are discussed and their methods of application shown. Finally the recommendations also include suggestions for patient clarification, monitoring and discharge. They should provide the examiner with concrete operating options and therefore above all increase patient safety.

Cryobiopsy increases the diagnostic yield of endobronchial biopsy: a multicentre trial

Forceps, brushes or needles are currently the standard tools used during flexible bronchoscopy when diagnosing endobronchial malignancies. The new biopsy technique of cryobiopsy appears to provide better diagnostic samples. The aim of this study was to evaluate cryobiopsy over conventional endobronchial sampling. A total of 600 patients in eight centres with suspected endobronchial tumours were included in a prospective, randomised, single-blinded multicentre study. Patients were randomised to either sampling using forceps or the cryoprobe. After obtaining biopsy samples, a blinded histological evaluation was performed. According to the definitive clinical diagnosis, the diagnostic yield for malignancy was evaluated by a Chi-squared test. A total of 593 patients were randomised, of whom 563 had a final diagnosis of cancer. 281 patients were randomised to receive endobronchial biopsies using forceps and 282 had biopsies performed using a flexible cryoprobe. A definitive diagnosis was achieved in 85.1% of patients randomised to conventional forceps biopsy and 95.0% of patients who underwent cryobiopsy (p<0.001). Importantly, there was no difference in the incidence of significant bleeding. Endobronchial cryobiopsy is a safe technique with superior diagnostic yield in comparison with conventional forceps biopsy.

[Survival and pattern of failure in palliative endobronchial HDR -- brachytherapy using iridium 192 in recurring bronchial carcinoma]

To evaluate the impact of palliative high dose rate brachytherapy on survival and a pattern of failure, we performed a matched pair study. 94 patients with tumor recurrence after external beam radiation received endobronchial brachytherapy. They were followed prospectively and matched retrospectively with 94 comparable patients who had not received brachytherapy. Matched parameters were age, gender, smoking behaviour, histology, tumor stage, EBRT-dose and fractionation. The leading cause of death in both groups was generalized tumor growth. In the combined therapy group, fatal hemorrage was 27.7 %, two and a half times higher than in the EBRT group with 10.6 %, whereas respiratory insufficiency in the brachytherapy group was 6.4 % and 11.7 % in the EBRT group. A complete remission after brachytherapy yielded a 10.5 months longer mean survival. Patients dying from fatal hemorrhage after endobronchial brachytherapy lived on average 10.2 months longer than matched EBRT patients dying from the same cause. Analyzing the time-course of fatal hemorrage in the brachytherapy group we conclude that - because of its early onset in the first 10 months after induction of therapy roughly 20 % of the deaths can be attributed to a radiation damage. In those patients who died after 10 months the major cause of fatal hemorrhage was the natural course of sqamous cell carcinoma with prolonged survival.

[A new rigid bronchoscope with a measuring tube for pressure and capnometry]

BACKGROUND

Pulmonary gas exchange under jet ventilation is usually controlled by pulse-oxymetry and blood gas analysis. Capnometry is not common in clinical use. Rigid bronchoscopes with pressure measurements are not known. Our aim was the development of a rigid bronchoscope with a built-in tube for the online measurement of airway pressure and gas composition.

METHODS

We measured the distribution of inspiratory pressure under jet ventilation over the length inside a 8 x 400 mm rigid bronchoscope in a lung model and in patients. A measuring tube was constructed for obtaining representative values of airway pressure and capnometry. Using a prototype of a new rigid bronchoscope with the built-in measuring tube (R. Wolf Company, Knittlingen, Germany) inspiratory pressure and expiratory CO2 were measured during interventional bronchoscopy. The measuring tube was connected to the pressure control port of the jet ventilator. We applied jet ventilation with frequencies of 10 to 12 pulses per minute.

RESULTS

The inspiratory pressure reaches after 10 cm distally the instrumental port a significant constant plateau. Via the built-in measuring tube representative measurement of pressure and gas can be made there. The correlation between arterial CO2 (paCO2) and expiratory CO2 (petCO2) was excellent (r = 0.96). To maintain normocapnia in 25 patients undergoing interventional bronchoscopy, the jet pressure had to be adjusted to values between 0.5 and 3.5 bar (median 2.5 bar). The responding inspiratory pressure varied from 3 to 25 mbar (median 15 mbar). A flexible bronchoscope in the working channel raises the airway pressure from 18 to 23 mbar. The automatic interruption of the jet-pulses by connecting the measuring tube to the pressure control port of the ventilator in order to prevent a barotrauma was found feasible.

CONCLUSIONS

Simultaneous online control of airway pressure and gas is possible with the new rigid bronchoscope. Pressure depending jet ventilators can be controlled via the measuring tube to minimise the risk of barotrauma.

[Argon plasma coagulation in bronchology: a new method--alternative or complementary?]

Argon plasma coagulation (APC) is a thermal coagulation technique that uses ionized argon to transmit high-frequency electrical current, contact free, to tissue. APC has been used in surgery for more than 20 years, particularly for the hemostasis of superficial bleeding. Although APC has become well established in gastrointestinal endoscopy since its introduction in 1991, very few reports of its use in bronchoscopy exist to date. From June 1994 to June 1998, 364 patients (80 women, 284 men), 88% with a confirmed malignant tumor, were treated prospectively in a total of 482 sessions. The single most common indication was recanalization of malignant airway stenoses (186 patients). The defined therapy objective was achieved with good results in 67% of patients. More than 90% of interventions were performed with rigid bronchoscopy. Despite less penetration compared with Nd:YAG laser, extensive bronchial tumors were treatable, in which coagulated tumor fractions were removed either with forceps or bronchoscope tip. The second indication was bleeding in the central airways (119 patients). Acute hemostasis was achieved in 118 patients, 20% in whom the flexible technique under local anesthesia was used. In 34 patients, APC was successfully used to recanalize occluded stents. Rare indications included benign endobronchial tumor, fistula conditioning before fibrin adhesion, and the treatment of scar tissue stenosis. Summarizing all complications, a rate of 3.7% "per treatment" was recorded. Two patients died within 24 hours; their deaths were not directly related to APC. APC is an effective and safe technique for the treatment of bronchologic tumor ablation and hemostasis and can be used with local anaesthetic with flexible bronchoscopy or rigid bronchoscopy with general anesthesia. Compared with Nd:YAG laser, APC is an economic alternative technique offering more effective hemostasis. Furthermore, APC is of particular value as a compliment to well-known techniques, increasing the options in interventional bronchoscopy.

[Experiences with fluorescence diagnosis and photodynamic therapy in a multimodality therapy concept of operated, recurrent bronchial carcinoma]

Even of those few patients who are operated because of bronchial cancer up to a quarter develop a recurrence. One reason is certainly that tumor-cells already present at the time of surgery are bronchoscopically invisible. Fluorescence methods might be able to detect these malignant cells. For patients with post-surgical recurrences the therapeutical choices are limited due to the loss of parenchyma. Photodynamic therapy (PDT) with the hematoporphyrine derivative Photofrin is one laborious but promising option. Based on an argon-dye laser we have developed a combined system for the diagnostical measurement of autofluorescence and Photofrin-induced fluorescence at 488 nm and the therapeutical PDT at 630 nm. Under the excitation with blue light from the argon laser, differences in the autofluorescence of malignant and benign cells can be distinguished. Following the injection of Photofrin a spectrum peak at 628 nm clearly delineates tumor cells. In six out of twelve patients with post-surgical recurrences a single PDT course resulted in tumor eradication. With additional PDT courses and brachytherapies local tumor control could be achieved in all cases. The general photosensitivity and the necessary light protection were tolerated by all patients. In order to avoid severer complications such as asphyxia, obstruction of bronchi and pneumotharaces resulting from fibrin-plugs and necrotic tissue following PDT must be considered. Especially in patients with pneumonectomy a careful surveillance and debridement is mandatory.

[Thoracic bilateral myelolipoma]

Diagnostics, histogenetic derivatives and determination of the mediastinal neoplasms can still be problematic today despite the use of CT and MRT. Although the exact location and determination of neoplasmic density help to reduce the differential diagnostic spectrum in some cases, in the case of a 50-year old patient it was only via thoracoscopy and the taking of specimens that the diagnosis of a bilateral paravertebral crescent-shaped tumour of the posterior mediastinum as a rare myelolipoma could be obtained. Formal and causal pathogenesis of myelopomas are referred to in this paper with special reference to the clinical and pathologico-anatomical findings.

The role of ultrasound assisted thoracoscopy in the diagnosis of pleural disease. Clinical experience in 687 cases

Ultrasonic examination is an established method used to differentiate between solid and liquid structures in the pleural space. It can estimate the volume of a pleural effusion and demonstrate whether the effusion is associated with loculations or adhesions. It is complementary to thoracoscopy. In the diagnosis of pleural disease ultrasonic-assisted thoracoscopy should only be used when the less invasive methods of diagnosis such as pleural aspiration for cytological, bacteriological and chemical examinations and needle biopsy of the pleura have not yielded a diagnosis. Although thoracoscopy is a relatively invasive procedure, it has the advantages of speed and accuracy in the diagnosis of pleural disease. This procedure is not widely used as it requires specialized instruments and equipment and may be time-consuming. The latter disadvantage may be minimized by the use of prior pleural sonography. The ultrasonic examination will indicate the optimal point of entry of the thoracoscopy to avoid adhesions. In order to evaluate feasibility, complications and clinical results in ultrasonic-assisted thoracoscopy, we investigated 687 patients with pleural diseases from 1987 to 1990. As prior induction of a pneumothorax under X-ray control was not necessary, the 20-30 min required for this procedure was saved in all patients. Very few complications were attributable to ultrasonic-assisted thoracoscopy as it could normally be performed under local anesthesia. A macroscopic diagnosis was made in 80% of malignant diseases and 77% of inflammatory diseases in our total of 687 thoracoscopies. The diagnosis of a malignant pleural effusion was confirmed histologically and cytologically in 95% of those 190 patients in whom it was present.(ABSTRACT TRUNCATED AT 250 WORDS)