Neurological Impact of Slower Rewarming during Bypass Surgery in Infants.

BACKGROUND: Hypothermia is a neuroprotective strategy during cardiopulmonary bypass. Rewarming entailing a rapid rise in cerebral metabolism might lead to secondary neurological sequelae. In this pilot study, we aimed to validate the hypothesis that a slower rewarming rate would lower the risk of cerebral hypoxia and seizures in infants. METHODS: This is a prospective, clinical, single-center study. Infants undergoing cardiac surgery in hypothermia were rewarmed either according to the standard (+1°C in < 5 minutes) or a slow (+1°C in > 5-8 minutes) rewarming strategy. We monitored electrocortical activity via amplitude-integrated electroencephalography (aEEG) and cerebral oxygenation by near-infrared spectroscopy during and after surgery. RESULTS: Fifteen children in the standard rewarming group (age: 13 days [5-251]) were cooled down to 26.6°C (17.2-29.8) and compared with 17 children in the slow-rewarming group (age: 9 days [4-365]) with a minimal temperature of 25.7°C (20.1-31.4). All neonates in both groups (n = 19) exhibited suppressed patterns compared with 28% of the infants > 28 days (p < 0.05). During rewarming, only 26% of the children in the slow-rewarming group revealed suppressed aEEG traces (vs. 41%; p = 0.28). Cerebral oxygenation increased by a median of 3.5% in the slow-rewarming group versus 1.5% in the standard group (p = 0.9). Our slow-rewarming group revealed no aEEG evidence of any postoperative seizures (0 vs. 20%). CONCLUSION: These results might indicate that a slower rewarming rate after hypothermia causes less suppression of electrocortical activity and higher cerebral oxygenation during rewarming, which may imply a reduced risk of postoperative seizures.

Retrospective investigation of >400 patients undergoing thoracic endovascular aortic repair with or without cerebrospinal fluid drainage.

OBJECTIVES: The aim of this study was to analyse the risks and benefits of cerebrospinal fluid drainage (CSFD) placement in patients undergoing thoracic endovascular aortic repair. METHODS: Between 2009 and 2020, 411 patients underwent thoracic endovascular aortic repair in 1 institution where 236 patients (57%) received a preoperative CSFD. Patient and outcome characteristics were retrospectively analysed and compared between patients with and without preoperative CSFD placement. RESULTS: Preoperative CSFD was performed significantly more frequently in elective patients, especially those undergoing distal stent graft extension following frozen elephant trunk-stent placement (P < 0.001). Significantly fewer CSFD was placed in patients with acute aortic injury (P < 0.001). The incidence of permanent spinal cord ischaemia (SCI) was higher in patients without preoperative CSFD [10 patients (2%) vs 1 patient (0.2%), P = 0.001]. Postoperative CSFD was placed in 3 patients (0.7%). Severe CSFD-associated complications affected 2 patients (0.5%) namely, a subdural spinal haematoma causing permanent paraplegia in one of those 2 patients. CONCLUSIONS: CSFS placement is associated with low procedural risk and can potentially help to prevent SCI. However, the SCI incidence is most likely also associated with other preoperative factors including the patient's haemodynamics. Hence, a general recommendation for placing a preoperative CSFD cannot be made when relying on the present evidence.

Risk Assessment of Red Cell Transfusion in Congenital Heart Disease.

BACKGROUND: The storage time of packed red blood cells (pRBC) is an indicator of change in the product's pH, potassium, and lactate levels. Blood-gas analysis is a readily available bedside tool on every intensive care ward to measure these factors prior to application, thus facilitating a calculated decision on a transfusion's quantity and duration.Our first goal is to assess the impact of storage time on pH, potassium, and lactate levels in pRBC. The influence of those parameters in the transfused children will then be evaluated. METHODS: In this retrospective study, we conducted blood-gas analyses of pRBC units before they were administered over 4 hours to neonates, infants, and children in our pediatric cardiac intensive care ward. All patients underwent regular blood-gas analyses themselves, before and after transfusion. RESULTS: We observed a highly significant correlation between the storage time of pRBC units and a drop in pH, as well as an increase in potassium and lactate of stored red cells (p< 0.0001). Median age of recipients with a complete blood-gas dataset was 0.1 (interquartile range [IQR] = 0.0-0.7) years; median pRBC storage duration was 6 (IQR = 5-8) days. Further analyses showed no statistically significant effect on children's blood gases within 4 hours after transfusion, even after stratifying for pRBC storage time ≤7 days and >7 days. CONCLUSION: Stored red blood cells show a rapid decrease in pH and increase in potassium and lactate. Slow transfusion of these units had no adverse effects on the recipients' pH, potassium, and lactate levels.

Results of open thoracoabdominal aortic replacement in patients unsuitable for or after endovascular repair with remaining disease components.

OBJECTIVES: Our goal was to evaluate outcomes in all-comer patients undergoing open thoracoabdominal aortic replacement either unsuitable for or after failed endovascular aortic repair. METHODS: Within a 4-year period, we analysed a consecutive series of 80 patients undergoing elective, urgent and emergency thoracoabdominal aortic replacement. Preoperative data, intraoperative data and outcomes were evaluated. Specific attention was given to technical refinements needed in patients after previous endovascular aortic repair. RESULTS: Eighty patients underwent thoracoabdominal aortic replacement: 11.3% (n = 9) had connective tissue disorders. Twenty-six patients (32.5%) had previous endovascular aortic repair and 54 (67.5%) did not have previous endovascular repair. The mean age was 64.2 ± 12 years, and 70% (n = 56) were male. The mean EuroSCORE was 7.9 ± 2.6. Urgent or emergency operations were done in 22.5% (n = 18). Overall mortality was 20% (n = 16); symptomatic spinal cord injury occurred in 5% (n = 4). We did not observe differences in survival according to the presence or absence of previous endovascular aortic repair (P = 0.524). Multivariate regression analysis revealed the amount of packed red blood cell units (P = 0.009, confidence interval 1.028-1.215, odds ratio = 1.117) as a predictor of in-hospital death. Follow-up was 100% (37.9 ± 15.8 months); freedom from aortic-related reintervention was 96.3%. CONCLUSIONS: Despite an early attrition rate, survival after open thoracoabdominal aortic replacement is excellent, and freedom from aortic-related reintervention is high. Open surgery continues to remain an essential component in the treatment armamentarium of acute and chronic thoracoabdominal aortic pathology.

Ex Vivo Allograft Perfusion for Complex Pediatric Heart Transplant Recipients.

BACKGROUND: Pediatric heart transplant (HTx) recipients with congenital heart defects require complex concomitant surgical procedures with the risk of prolonging the allograft's ischemic time. Ex vivo allograft perfusion with the Organ Care System (OCS; Transmedics, Andover, MA) may improve survival of these challenging patients. METHODS: In this retrospective, single-center study a consecutive series of 8 children with allografts preserved using the OCS was compared with 13 children after HTx with cold storage of the donor heart from March 2018 to March 2020. RESULTS: Median recipient age in the control group was 18 months (range, 1-189) versus 155 months (range, 83-214) in the OCS group, and the baseline differences between the 2 groups were not significant. Fifty percent of the children in the OCS group had complex congenital heart defects (vs 15% of the control subjects). Median operation time during HTx in the OCS group was 616 minutes (range, 270-809) versus 329 minutes (range, 283-617). Because of the time of ex vivo allograft perfusion (265 minutes [range, 202-372]) median total ischemia time was significantly shorter in the OCS group: 78 minutes (range, 52-111) versus 222 minutes (range, 74-326). The incidence of primary graft, renal, or hepatic failure did not differ between the groups. Graft function and the occurrence of any treated rejection at follow-up revealed no significant difference between the 2 groups. One-year survival was 88% in the OCS group (vs 85%). CONCLUSIONS: Ex vivo allograft perfusion enabled complex pediatric HTx, yielding outcomes as positive as those of children whose donor hearts were stored in ice-cold solution.

A logistic regression analysis comparing minimalistic approach and intubation anaesthesia in patients undergoing transfemoral transcatheter aortic valve replacement.

AIMS: Patients with postoperative delirium (POD) after transcatheter aortic valve replacement (TAVR) are ventilated and hospitalized longer and suffer increased in-hospital mortality. This study hypothesized that a minimalistic approach with conscious sedation during transfemoral aortic valve replacement (TF-AVR) protects against delirium, time of mechanical ventilation, and increased length of stay in intensive care unit (ICU) compared to intubation anaesthesia. METHODS AND RESULTS: 308 patients which underwent TF-AVR in our centre between 01/2013 and 08/2017 were retrospectively evaluated regarding postoperative delirium, time of mechanical ventilation, and days in ICU. TF-AVR was performed with intubation anaesthesia in 245 patients and with conscious sedation in 63. The operative risk estimated by the logEUROScore was similar in both groups (intubation: 13.28 +/-9.06%, conscious sedation: 12.24 +/-6.77%, p = 0.395). In the conscious sedation group procedure duration was shorter (0.61 +/-0.91h vs. 1.75 +/-0.96h, p<0.001). The risk for intraprocedural complications was not influenced by the anaesthesia method (OR conscious sedation instead of intubation 1.66, p = 0.117), but days on ICU (-2.21 days, p<0.0001) and minutes of mechanical ventilation (-531.2 min, p < 0.0001) were reduced. Furthermore, the risk of POD was decreased when TF-AVR was performed under conscious sedation (6.35% vs. 18.18%, OR 0.29, p = 0.021). CONCLUSIONS: Time of mechanical ventilation, risk of POD, and days on ICU were substantially reduced in patients who underwent TF-AVR under conscious sedation. Our data suggest that TF-AVR with conscious sedation is safe with a beneficial postoperative course in clinical practice, and should be considered the favoured approach.

Implementing and Assessing a Standardized Protocol for Weaning Children Successfully From Extracorporeal Life Support.

Extracorporeal life support (ECLS) weaning is a complex interdisciplinary process with no clear guidelines. To assess ventricular and pulmonary function as well as hemodynamics including end-organ recovery during ECLS weaning, we developed a standardized weaning protocol. We reviewed our experience 2 years later to assess its feasibility and efficacy. In 2015 we established an inter-professional, standardized, stepwise protocol for weaning from ECLS. If the patient did not require further surgery, weaning was conducted bedside in the intensive care unit (ICU). Most of the weaning procedures are guided via echocardiography. Data acquisition began at baseline level, followed by four-step course (each step lasting 10 min), entailing flow-reduction and ending 30 min after decannulation. Moreover, data from the preprotocol era are presented. Between May 2015 and 2017, 26 consecutive patients (18 male), median age 177 days (2 days-20 years) required ECLS with median support of 4 (2-11) days. Excluding eight not weanable patients, 21 standardized weaning procedures were protocolled in the remaining 18 children. Our generally successful protocol-guided weaning rate (with at least 24-h survival) was 89%, with a discharge home rate of 58%. Practical application of the novel standard protocol seems to facilitate ECLS weaning and to improve its success rate. The protocol can be administered as part of standard bedside ICU assessment.

Aortic Replacement After TEVAR-Diameter Correction With Modified Use of the Siena Prosthesis.

BACKGROUND: To report a new technique for diameter correction in patients after thoracic endovascular aortic repair (TEVAR) with large stent-grafts using the Vascutek Siena 4-branch collared prosthesis (Vascutek Terumo, Inchinnan, Scotland, UK) in patients undergoing thoracoabdominal (TA) aortic replacement. METHODS: Within a 24-month period, 39 patients underwent TA replacement at our center. Of these, 6 patients had undergone previous TEVAR with large stent-grafts (42 to 48 mm diameter). Indications for TEVAR were aneurysm formation in 3 patients and residual type B aortic dissection (status post repair of type A dissection) in 3 patients. In these patients, the Vascutek Siena 4-branch prosthesis was used in a reversed fashion, removing the elephant trunk portion and using the sewing collar for diameter correction at the anastomotic site. RESULTS: No 30-day mortality and no stroke or symptomatic spinal cord ischemia was observed. Median diameter of the TEVAR graft at the anastomotic site was 44 mm. Median size of the Siena graft used was 26 mm. Diameter correction was successfully achieved in all patients by tailoring the sewing collar of the Siena 4-branch prosthesis to the individual need according to the diameter of the distal end of the stent-graft. CONCLUSIONS: Using the sewing collar of the Vascutek Siena 4-branch prosthesis for diameter correction in patients undergoing TA replacement after previous TEVAR with large stent-grafts adds a useful adjunct to the armamentarium of options in a growing patient population.

First serial in vivo results of mechanical circulatory support in children with a new diagonal pump.

OBJECTIVES: Mechanical circulatory support (MCS) is a rescue therapy for infants and children suffering from severe cardiorespiratory failure with specific system-related complications like bleeding, thromboembolism and device failure. Novel circuit components for temporary MCS with improved haemodynamic properties may improve patients' outcome and reduce system-related morbidities. The Deltastream DP3 (Medos Medizintechnik AG, Stolberg, Germany) is a newly designed rotational pump with a diagonally streamed impeller that can be used in children of all ages (priming volume 16 ml, flow 0-8 l/min). The aim of this study was to analyse the feasibility and safety of the DP3 pump system in children. METHODS: We retrospectively investigated a consecutive series of 16 children [median age 0.9 months (0.1-55 months), median weight 3.2 kg (2.5-14 kg)]. The DP3 circuit was used 22 times in these children for different indications: (I) extracorporeal life support (ECLS) in post-cardiotomy heart failure (n = 11), (II) ECLS in cardiopulmonary resuscitation (CPR) (n = 7) and (III) extracorporeal membrane oxygenation (ECMO) in acute respiratory distress syndrome (ARDS) (n = 4). RESULTS: Median duration of MCS was 4 days (0-18 days), 12 patients (75%) were weaned successfully from MCS, 4 of these children (25%) died after weaning, with a median survival time of 15 days (6-28 days). Overall survival rate was 50% and all 8 survivors were discharged home without neurological injury. There was no case of severe bleeding, thromboembolic complications or device failure. Mean lactate dehydrogenase (LDH) before MCS was 700 (±384) U/l, and increased to a maximum of 2279 (±2635) U/l during MCS (P = 0.04). Baseline D-dimer values were 3.4 (±3.0) mg/l and rose significantly to 19.5 (±11.5) mg/l during MCS (P < 0.001). The mean of the highest plasma-free haemoglobin during MCS was 21.0 (±42.9) mg/dl. The increase in plasma-free haemoglobin correlated moderately with the duration of MCS (Pearson's r: 0.78). CONCLUSION: The use of the Deltastream DP3 seems to be safe and effective for MCS in children and may show a low degree of haemolysis. We observed no system-related complications and an overall good outcome in this demanding patient cohort.

Early prediction of capillary leak syndrome in infants after cardiopulmonary bypass.

OBJECTIVES: As an inflammatory reaction after cardiac surgery involving cardiopulmonary bypass (CPB), capillary leak syndrome (CLS) is associated with increased morbidity, especially in newborns and infants. We investigated whether different cytokines measured via microdialysis can monitor local inflammation in adipose tissue subcutaneously and predict the development of CLS early, before clinical signs appear. Furthermore, we investigated whether there are age-related differences between the inflammatory responses in newborns and infants. METHODS: We performed a prospective study taking serial measurements of the inflammatory response detected in subcutaneous adipose tissue up to 24 h postoperatively. The cohort consisted of 23 neonates and infants (median age 155, range 6-352 days; median body weight 5.4 kg, range 2.6-9.2 kg) who underwent congenital heart surgery with CPB. Microdialysis catheters were introduced in one lateral thigh subcutaneously using a velocity of 1.0 µl/min. Serial microdialysis analyses for cytokines (interleukin [IL]-6, IL-8, IL-10) and complement activation (C3a) were performed. CLS was quantified by X-ray subcutaneous-thoracic ratios. RESULTS: The median bypass time was 150 min (range 42-432 min) and the aortic cross-clamp time 76 min (range 0-188 min). Six out of 23 infants developed postoperative CLS. Younger age (P = 0.02) and longer bypass time (r = 0.48; P = 0.021) correlated strongly with the development of CLS. Pro- and anti-inflammatory cytokines and complement activation were detected subcutaneously in all patients. The highest levels of IL-6 (55.0 pg/ml) and IL-8 (65.9 pg/ml) were detected 2 h after CPB. During surgery, the C3a level rose dramatically (167.1 ng/ml), followed by a release of IL-10 at the end of CPB. Patients with CLS produced a characteristic and significant second peak of C3a at 8 h postoperatively (CLS 63.8 ng/ml vs non-CLS 23.5 ng/ml; P < 0.01). We detected an aged-related difference in the release of IL-6 and C3a. Longer intubation time (r = 0.63; P = 0.001), higher inotropic demand (r = 0.67; P = 0.001) and higher serological lactate levels (r = 0.65; P = 0.001) correlated closely with the development of CLS. CONCLUSION: Diagnostic microdialysis can detect local inflammation and may predict the development of CLS early before severe clinical signs appear.