Elevated intrathoracic CO2 pressure during thoracoscopic surgery decreases regional cerebral oxygen saturation in neonates and infants-A pilot study

Intraoperative Regional Cerebral Oxygenation During Pediatric Thoracoscopic Surgery: A Systematic Review

Background: Ventilating a pediatric patient during thoracoscopy is challenging. Few studies have highlighted the impact of capnothorax in children by measuring regional cerebral oxygen saturation (rcSO2) with near infrared spectroscopy. In this systematic review, we aimed to summarize the data from relevant studies and assess whether thoracoscopy in children is associated with intraoperative pathological cerebral desaturation. Methods: The authors systematically searched four databases for relevant studies on the measurement of rcSO2 during pediatric thoracoscopic procedures. The primary outcome was the proportion of patients with pathological desaturation, that is, >20% decline in the intraoperative rcSO2. Risk of bias among the included studies was estimated using the Newcastle-Ottawa scale. Results: The systematic search resulted in 776 articles, of which 7 studies were included in the analysis. In total, 88 patients (99 procedures) with an age ranging from 0 days to 8.1 years were included. Of these, 43 (49%) patients were neonates. The included cohort had esophageal atresia and tracheoesophageal fistula (n = 26), long-gap esophageal atresia (n = 5), congenital diaphragmatic hernia (n = 14), and congenital pulmonary airway malformations and other conditions needing lung resection (n = 43). Of the total 99 procedures, pathological desaturation was noticed in 13 (13.1%, 95% confidence interval 7.2-21.4) of them. Upon quality assessment, most of the studies were weaker in the selection and comparability domains. Conclusion: In this review, pathological cerebral desaturation was noticed in 13.1% of the pediatric thoracoscopic procedures. However, due to limited methodological quality of the included studies, further randomized multicentric studies comparing rcSO2 in open versus thoracoscopic surgeries are needed to derive definitive conclusions.

The effect of intraoperative cerebral oxygen desaturations on postoperative cerebral oxygen metabolism in neonates and infants a pilot study

INTRODUCTION

Cerebral oxygen desaturation during pediatric surgery has been associated with adverse perioperative outcomes. The aim of this pilot study was to analyze the frequency and severity of intraoperative cerebral oxygen desaturations and their impact on postoperative cerebral oxygen metabolism in neonates and infants undergoing pediatric surgery.

METHODS

In a prospective pilot study, intra- and postoperative regional cerebral oxygen saturation and blood flow were measured noninvasively using a device combining laser Doppler flowmetry and white-light-spectrometry. Thirty-seven consecutive neonates and infants undergoing noncardiac surgery under general anesthesia for more than 30 min and necessity for invasive arterial blood pressure monitoring were included. Patients with pre-known congenital structural heart disease or cerebral disease were excluded. Continuously brain monitor recording was started in sedated patients before induction of anesthesia (preoperative baseline) and was completed 1 h postoperatively in the PICU in sedated, intubated, and mechanically ventilated states at the PICU (postoperative state). Baseline and postoperative state for cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen were calculated.

RESULTS

Seventeen (46%) of the 37 studied neonates and infants suffered from intraoperative periods of regional cerebral oxygen desaturation below 20% of the baseline (event group). Severity of cerebral desaturations was median 4.0%min/h [range 0.1-58.7; interquartile range [IQR] 0.99-21.29]. In the event group, the duration of surgery was significantly longer (median 135 min [range 11-260; IQR 113.5-167.0] vs median 46.5 min [range 11-180; IQR 30.5-159.3]; difference of -62.94; 95% confidence interval [CI] -105.17 to -20.71; p = .021). In the event group, cerebral fractional tissue oxygen extraction (median 0.41 [range 0.20-0.55; IQR 0.26-0.44] vs. median 0.27 [range 0.11-0.41; IQR 0.20-0.31]; difference of -0.11; 95% CI -0.17 to -0.05; p = .001) and approximated cerebral metabolic rate of oxygen (median 6.15 arbitrary unit [range 2.69-12.07; IQR 5.12-7.21] vs. median 4.14 arbitrary unit [range 1.78-7.86; IQR 3.82-6.31]; difference of -1.76; 95% CI -3.03 to -0.49; p = .009) were significantly higher and the cerebral regional oxygen saturation (median 58.99% [range 44.87-79.1; IQR 54.26-72.61] vs median 70.94% [range 57.9-86.13; IQR 67.07-76.59]; difference of 10.01; 95% CI 4.13-15.90; p = .002) significantly lower after surgery compared to the nonevent group.

DISCUSSION

The increase of approximated cerebral metabolic rate of oxygen could indicate an elevated oxidative energy metabolism in the "stressed" brain, due to repair processes. The increased cerebral fractional tissue oxygen extraction fits with the decreased NIRS cerebral oxygenation. Our data suggest that an increase in cerebral oxygen metabolism was the cause.

CONCLUSION

Cerebral oxygen desaturation during major surgery in neonates and infants is associated with early postoperative increased cerebral oxygen extraction and possibly increased cerebral oxygen metabolism.

Effects of nonintubated thoracoscopic surgery on postoperative neurocognitive function: a randomized controlled trial

OBJECTIVES

Postoperative neurocognitive disorder following thoracoscopic surgery with general anaesthesia may be linked to reduced intraoperative cerebral oxygenation and perioperative inflammation, which can potentially be exacerbated by mechanical ventilation. However, nonintubated thoracoscopic surgery, which utilizes regional anaesthesia and maintains spontaneous breathing, provides a unique model for studying the potential benefits of avoiding mechanical ventilation. This approach allows investigation into the impact on perioperative neurocognitive profiles, inflammatory responses and intraoperative cerebral oxygen levels.

METHODS

In total, 110 patients undergoing thoracoscopic surgery were randomly equally assigned to the intubated group and the nonintubated group. Regional cerebral oxygenation was monitored during surgery. Serum neuroinflammatory biomarkers, including interleukin-6 and glial fibrillary acidic protein, were measured at baseline (before surgery) and 24 h after surgery. Postoperative complication severity was compared using the Comprehensive Complication Index. The primary outcome was perioperative changes in neurocognitive test score, which was assessed at baseline, 24 h and 6 months after surgery.

RESULTS

Patients in the nonintubated group had higher neurocognitive test scores at 24 h (69.9 ± 10.5 vs 65.3 ± 11.8; P = 0.03) and 6 months (70.6 ± 6.7 vs 65.4 ± 8.1; P < 0.01) after surgery and significantly higher regional cerebral oxygenation over time during one-lung ventilation (P = 0.03). Patients in the intubated group revealed a significantly higher postoperative serum interleukin-6 level (group by time interaction, P = 0.04) and a trend towards a significantly higher serum glial fibrillary acidic protein level (group by time interaction, P = 0.11). Furthermore, patients in the nonintubated group had a significantly lower Comprehensive Complication Index (9.0 ± 8.2 vs 6.1 ± 7.1; P < 0.05).

CONCLUSIONS

Nonintubated thoracoscopic surgery was associated with improved postoperative neurocognitive recovery, more stable intraoperative cerebral oxygenation, ameliorated perioperative inflammation and attenuated postoperative complication severity.

Abdominal and Peripheral Tissue Oxygen Supply during Selective Lower Body Perfusion for the Surgical Repair of Congenital Heart Disease: A Pilot Study

Background: Lower body perfusion (LBP) may be a strategy for maintaining organ perfusion during congenital heart disease surgery. It is hypothesized that renal and lower limb oxygen supply during LBP is superior to off-pump surgery and comparable to that of a standard cardiopulmonary bypass (CPB). Methods: in this prospective single-center study, patients aged <1 year were recruited if they were scheduled for a correction of aortic arch anomalies using antegrade cerebral perfusion and LBP (group 1), a repair of coarctation during aortic cross-clamping (group 2), or surgery under whole-body CPB (group 3). Renal (prefix “r”) and peripheral (prefix “p”) oxygen saturation (SO2), hemoglobin amount (Hb), blood velocity (Velo), and blood flow (Flow) were measured noninvasively. Results: A total of 23 patients were included (group 1, n = 9; group 2, n = 5; group 3, n = 9). Compared to the baseline values, rSO2 and pSO2 decreased significantly in group 2 compared to groups 1 and 3. Conversely, rHB significantly increased in group 2 compared to groups 1 and 3, reflecting abdominal venous stasis. Compared to group 3, group 1 showed a significantly lower pFlow during CPB; however, rFlow, pFlow, and pVelo did not differ. Conclusion: according to these observations, LBP results in an improved renal oxygen supply compared to off-pump surgery and may prove to be a promising alternative to conventional CPB.

Use of combined cerebral and somatic renal near infrared spectroscopy during noncardiac surgery in children: a proposed algorithm

Cerebral near infrared spectroscopy (NIRS) monitoring has been extensively applied in neonatology and in cardiac surgery, becoming a standard in many pediatric cardiac centers. However, compensatory physiological mechanisms favor cerebral perfusion to the detriment of peripheral tissue oxygenation. Therefore, simultaneous measurement of cerebral and somatic oxygen saturation has been advocated to ease the differential diagnosis between central and peripheral sources of hypoperfusion, which may go undetected by standard monitoring and not mirrored by cerebral NIRS alone. A clinical algorithm already exists in cardiac surgery, aimed to correct intraoperative cerebral oxygen desaturations. A similar algorithm still lacks in noncardiac pediatric surgery. The goal of this paper is to propose a clinical algorithm for the combined use of cerebral and somatic NIRS monitoring during anesthesia in the pediatric population undergoing noncardiac surgery. A panel of experienced pediatric anesthetists developed the algorithm that is based on the clinical experience and intraoperative observations. It aims to lessen the current variability in interpreting NIRS measurement. Multisite NIRS monitoring was achieved applying one pediatric sensor to the forehead for cerebral tissue perfusion reading and a second one to the decumbent lumbar region for recording somatic renal tissue perfusion. The algorithm describes a sequence of acts aimed to identify the putative cause of intraoperative organ tissue desaturation and suggests clinical interventions expected to restore adequate tissue perfusion. It is composed of two arms: the main arm includes patients with an observed decrease in cerebral perfusion (CrO2), the second one includes those with a stable CrSO2 with declining RrSO2. Described also are five clinical cases of infants and neonates in whom pathological alterations of organ perfusion were detected using intraoperative multisite NIRS monitoring, portrayed in the accompanying figures (Annex).

Effect of different mechanical ventilation modes on cerebral blood flow during thoracoscopic surgery in neonates: A randomised controlled trial

Background and Aims:

Infants exposed to major surgery are at risk of injuries to the immature brain because of reduced arterial oxygen saturation. This study compared the effect of volume-controlled ventilation (VCV) versus pressure-controlled ventilation (PCV) on cerebral oxygenation in neonates subjected to repair of tracheoesophageal fistula (TEF) under video-assisted thoracoscopic surgery (VATS).

Methods:

This randomised controlled study included 30 full-term neonates scheduled for VATS for managing TEF under general anaesthesia. They were randomised to either VC group (n = 15), who received VCV, or PC group (n = 15), who received PCV. Cerebral oxygenation (rScO₂) was monitored throughout the surgery with documentation of episodes of cerebral desaturation. Peripheral oxygen saturation, partial pressure of carbon dioxide (PaCO₂), and end-tidal carbon dioxide were recorded at baseline, after induction of anaesthesia, and every 30 min till the end of the surgery.

Results:

rScO₂ was significantly higher in the PC group than the VC group at baseline and was significantly higher in the VC group after 15 min (P = 0.041). Later, it was comparable in both the groups up to 60 min after starting the surgery. Cerebral desaturation was significantly more common in the PC group (80%) compared to VC group (33.3%) (P = 0.010). PC group required higher fraction of inspired oxygen and positive end-expiratory pressure to prevent cerebral desaturation. PaCO₂ was significantly higher in the PC group than the VC group at 30 and 60 min (P = 0.005 and 0.029).

Conclusion:

VCV is safer than PCV for cerebral oxygenation during VATS in neonates.

Thoracoscopic surgery for congenital diaphragmatic hernia in neonates: Should it be the first choice?

OBJECTIVE

Congenital diaphragmatic hernia (CDH) is an uncommon but potentially life-threatening surgical condition in neonates. Surgery can be performed by either open or thoracoscopic techniques. In this study, we compared the clinical efficacy, safety, and effectiveness of thoracoscopic and open CDH repair.

METHODS

A retrospective review of neonates with CDH who underwent operations at our hospital from 2013 to 2021 was performed. The various perioperative parameters were compared between neonates undergoing thoracoscopic and open surgery.

RESULTS

There were 50 neonates in this study (37 in the thoracoscopic group and 13 in the open group). Thoracoscopic surgery was associated with significantly shorter hospital stay (13.32 vs. 18.77 days, p < 0.001); shorter duration of postoperative mechanical ventilation (3.70 vs. 5.98 days, p < 0.001); early feeding (4.34 vs. 7.46 days, p < 0.001); and shorter time to reach optimal feeding (8.21 vs. 13.38 days, p < 0.001). There was one postoperative death in the open group and no death in the thoracoscopic group. The median follow-up time of the two groups was 23.8 months (20.5 months in open group and 25.0 months in thoracoscopic group). Thoracoscopic surgery was associated with lower recurrence rates, but the difference was not statistically significant (2.7% vs. 7.7%, p = 0.456).

CONCLUSION

Thoracoscopy CDH repair, a safe and effective surgical technique for neonates, has better cosmesis, faster postoperative recovery, and a lower recurrence rate than other procedures. It can be considered the first choice for CDH treatment for neonates among experienced surgeons.

Neurodevelopmental outcome of patients with congenital gastrointestinal malformations: a systematic review and meta-analysis

AIM

Children with congenital gastrointestinal malformations may be at risk of neurodevelopmental impairment due to challenges to the developing brain, including perioperative haemodynamic changes, exposure to anaesthetics and postoperative inflammatory influences. This study aggregates existing evidence on neurodevelopmental outcome in these patients using meta-analysis.

METHOD

PubMed, Embase and Web of Science were searched for peer-reviewed articles published until October 2019. Out of the 5316 unique articles that were identified, 47 studies met the inclusion criteria and were included. Standardised mean differences (Cohen's d) between cognitive, motor and language outcome of patients with congenital gastrointestinal malformations and normative data (39 studies) or the studies' control group (8 studies) were aggregated across studies using random-effects meta-analysis. The value of (clinical) moderators was studied using meta-regression and diagnostic subgroups were compared.

RESULTS

The 47 included studies encompassed 62 cohorts, representing 2312 patients. Children with congenital gastrointestinal malformations had small-sized cognitive impairment (d=-0.435, p<0.001; 95% CI -0.567 to -0.302), medium-sized motor impairment (d=-0.610, p<0.001; 95% CI -0.769 to -0.451) and medium-sized language impairment (d=-0.670, p<0.001; 95% CI -0.914 to -0.425). Patients with short bowel syndrome had worse motor outcome. Neurodevelopmental outcome was related to the number of surgeries and length of total hospital stay, while no relations were observed with gestational age, birth weight, age and sex.

INTERPRETATION

This study shows that children with congenital gastrointestinal malformations exhibit impairments in neurodevelopmental outcome, highlighting the need for routine screening of neurodevelopment during follow-up.

Cerebral Oxygenation by Near-Infrared Spectroscopy in Infants Undergoing Thoracoscopic Lung Resection

Background: Thoracoscopic resection is the standard of care for congenital lung malformations (CLMs) in infants. However, there is rising concern that capnothorax may affect cerebral perfusion and oxygenation, carrying potential long-term effects on neurodevelopmental behavior. The aim of our study was to investigate, using near-infrared spectroscopy (NIRS), the regional cerebral oxygenation (CrSO₂) in infants undergoing thoracoscopic lung resection; the secondary aim was to assess the relationship between rSO₂ and standard monitoring. Methods: In this retrospective study, we reviewed all infants (<1 year old, ASA II) who underwent thoracoscopic CLM resection in double-lung ventilation under fixed capnothorax parameters (5 mmHg of pressure, 1 L/minute flow), standardized anesthetic protocol, standard monitoring, and multisite NIRS in our center. We focused our attention on 8 anesthetic and surgical maneuvers, potentially affecting tissue oxygen saturation. Results: Ten infants met the inclusion criteria. At surgery, median age was 5.5 (4-7) months, median weight 7.2 (6.6-8) kg, median operative time 110 (55-180) minutes, and median capnothorax duration 79 (34-168) minutes. No conversion to open surgery occurred. CrSO₂ values remained within clinically accepted values during thoracoscopy, beside a CrSO₂ drop >20% of basal value in 1 patient, during capnothorax induction. Renal NIRS added very little to standard monitoring, which appeared generally inadequate to consistently appraise end-organ perfusion. ETCO₂ best correlated with CrSO₂ variations, suggesting to be able to realistically predict them. Conclusions: The thoracoscopic treatment of CLMs under the given conditions appears well tolerated in infants, pending the continuous adjustment of ventilator settings by an experienced anesthetist, confident with NIRS technology.

Insufflation in minimally invasive surgery: Is there any advantage in staying low?

AIM

Minimally invasive repair of esophageal atresia with tracheoesophageal fistula (EA/TEF) and congenital diaphragmatic hernia (CDH) is feasible and confers benefits compared to thoracotomy or laparotomy. However, carbon dioxide (CO₂) insufflation can lead to hypercapnia and acidosis. We sought to determine the effect of lower insufflation pressures on patients' surrogate markers for CO₂ absorption - arterial partial pressure of CO₂ (PaCO₂), end tidal CO₂ (EtCO₂) and pH.

METHODS

Single center retrospective review, including neonates without major cardiac anomaly. Selected patients formed 2 groups: Historical pressure (HP) group and low pressure (LP) group. We reported on the patients' preoperative characteristics that potentially confound the degree of CO₂ absorption or elimination. Outcome measures were perioperative PaCO₂, EtCO₂, arterial pH and anesthetic time.

RESULTS

30 patients underwent minimally invasive surgery for CDH and 24 patients for EA/TEF with similar distribution within the HP and LP group. For CDH patients as well as for EA/TEF patients, there were no significant differences in their preoperative characteristics or surgery duration comparing HP and LP groups. With a decrease in insufflation pressure in CDH patients, there were a significant decrease (p = 0.002) in peak PaCO₂ and an improvement in nadir pH (p = 0.01). For the EA/TEF patients, the decrease in insufflation pressure was associated with a significant decrease (p = 0.03) in peak EtCO₂. Considering all 54 patients, we found EtCO₂ to be highly significantly inversely correlated with pH and positively correlated with intraoperative PaCO₂ (p < 0.001). Baseline Hb was inversely correlated with mean EtCO₂ (p < 0.001).

CONCLUSION

With lower insufflation pressures, CDH patients had significantly improved hypercapnia and acidosis, while EA/TEF patients had significantly reduced EtCO₂. EtCO₂ was correlated with acidosis and hypercapnia.

TYPE OF STUDY

Retrospective case control study.

LEVEL OF EVIDENCE

Level III.

Blood Glucose and Lactate Levels and Cerebral Oxygenation in Preterm and Term Neonates-A Systematic Qualitative Review of the Literature

Background: Cerebral oxygenation monitored non-invasively by near-infrared spectroscopy (NIRS) is of increasing interest in neonatal care. Cerebral oxygenation is determined by cerebral oxygen delivery and cerebral oxygen consumption. Oxygen delivery as well as oxygen consumption might be influenced by metabolic parameters like blood glucose and lactate. Objective: The aim of the present systematic qualitative review is therefore to identify and summarize all studies, which describe cerebral oxygenation measured with NIRS and blood glucose and/or blood lactate levels in neonates. Data sources: A systematic search of Ovid Embase and PubMed was performed. Search terms included near-infrared spectroscopy, fractional tissue oxygen extraction, cerebral tissue oxygen saturation, regional cerebral tissue oxygen saturation, oxygenation, term, and preterm neonates, cesarean delivery, transition, after-birth, newborn, vaginal delivery, cesarean delivery, baby, neonatal transition, metabolism, lactate, glucose, and blood glucose level. Study selection/data synthesis: Studies analyzing cerebral oxygenation and blood glucose and/or blood lactate levels in neonates were included. Animal studies, duplicates, or studies in non-English language were excluded. Results: Twenty-five studies were identified that describe blood glucose and/or blood lactate levels as primary or secondary outcome parameters with additional measured cerebral oxygenation by NIRS in neonates. Twelve studies were included with blood glucose measurements: four described an association between blood glucose levels and cerebral oxygenation, two show no association, and six do not report on possible associations. Eighteen studies were included with lactate measurements: one describe an association between lactate levels and cerebral oxygenation, while three show no association and 14 do not report on possible associations. Discussion: The influence of blood glucose and blood lactate levels on the cerebral oxygenation in neonates is still controversial. However, there seems to be an association between cerebral oxygenation and the metabolic parameter blood glucose and lactate, which need further investigation.

Culture of safety and error traps in pediatric thoracoscopy

Growing adoption of thoracoscopy by pediatric surgeons has resulted in increasingly complex operations being performed. Although common complications of these procedures have decreased with experience, surgeons are still at risk to fall into error traps where routine practice in uncommon situations results in unanticipated complications. A background culture of safety that rewards multidisciplinary communication, teamwork, openness and standardization of care can assist surgeons to recognize, address and report error traps when they arise. This article serves to encourage a culture of safety and raise awareness of error traps in pediatric thoracoscopy to minimize potential harm and improve quality of care.

[Clinical comparative study of thoracoscopic assisted reduction and traditional manual reduction with percutaneous intramedullary nail internal fixation for mid-clavicular fractures]

Objective

To compare the effectiveness of thoracoscopic assisted reduction and traditional manual reduction with percutaneous intramedullary nail internal fixation in the treatment of mid-clavicular fractures.

Methods

A prospective randomized controlled trial was conducted. Twenty-two patients with mid-clavicular fractures who met the selection criteria between March 2012 and March 2017 were recruited and randomly divided into trial group (7 cases, thoracoscopic assisted reduction and percutaneous intramedullary nail fixation) and control group (15 cases, traditional manual reduction and percutaneous intramedullary nail fixation). There was no significant difference in gender, age, side, cause of injury, fracture classification, interval between injury and operation between the two groups ( P>0.05). The operation time and fracture healing time were recorded and compared between the two groups. The effectiveness was evaluated by Constant-Murley scale at 6 months after operation, which included subjective evaluation indexes (functional activity and pain) and objective evaluation indexes (range of motion of shoulder joint and muscle strength).

Results

The operation time of the trial group was significantly longer than that of the control group ( t=5.881, P=0.000). Patients in both groups were followed up 7-20 months, with an average of 11 months. Satisfactory anatomical reduction achieved in all patients, and all incisions healed by first intension. In the control group, 1 patient had difficulty in removing the intramedullary nail, and 1 patient had fracture nonunion. No fracture nonunion or intramedullary nail rupture in the other patients of two groups. There was no significant difference in fracture healing time between the two groups ( t=0.764, P=0.453). At 6 months after operation, there was no significant difference in Constant-Murley scale between the two groups ( P>0.05).

Conclusion

The treatment of the mid-clavicular fracture by using thoracoscopic assisted reduction with intramedullary nail internal fixation requires longer operation time, but does not require fluoroscopy. The effectiveness is comparable to that of traditional surgery.

Perioperative Cerebral Oxygenation Metabolism in Neonates with Hypoplastic Left Heart Syndrome or Transposition of the Great Arteries

Optimizing oxygen delivery to the brain is one of the main goals in children with congenital heart defects after surgery. It has been shown that cerebral oxygen saturation (cSO2) is depressed within the first day after neonatal cardiopulmonary bypass surgery. However, peri-operative cerebral oxygen metabolism has not yet been assessed in previous studies. The aim of this study was to describe the peri-operative changes in cerebral oxygen metabolism in neonates with congenital heart defects following cardiopulmonary bypass surgery. Prospective observational cohort study. PICU of a tertiary referral center. Fourteen neonates with hypoplastic left heart syndrome (HLHS) undergoing Norwood procedure and 14 neonates with transposition of great arteries (TGA) undergoing arterial switch operation (ASO) were enrolled. Pediatric heart surgery. We measured non-invasively regional cSO2 and microperfusion (rcFlow) using tissue spectrometry and laser Doppler flowmetry before and after surgery. Cerebral fractional tissue oxygen extraction (cFTOE), the arterio-cerebral difference in oxygen content (acDO2) and approximated cerebral metabolic rate of oxygen (aCMRO2) were calculated. According to the postsurgical hemodynamics, arterial saturation (aSO2) normalized immediately after surgery in the TGA group, whereas HLHS patients still were cyanotic. cSO2 significantly increased in TGA group over 48 h after ASO (p = 0.004) and was significantly higher compared to HLHS group after Norwood procedure. cFTOE as a risk marker for brain injury was elevated before surgery (TGA group 0.37 ± 0.10, HLHS group 0.42 ± 0.12) and showed a slight decrease after ASO (p = 0.35) but significantly decreased in patients after Norwood procedure (p = 0.02). Preo-peratively, acDO2 was significantly higher in patients with HLHS compared to patients with TGA (7.7 ± 2.5 vs. 5.2 ± 1.6 ml/dl, p = 0.005), but normalized in the posto-perative course. Before surgery, the aCMRO2 was slightly higher in the HLHS group (5.1 ± 1.5 vs. 3.9 ± 2.5 AU, p = 0.14), but significantly decreased after Norwood procedure (- 1.6 AU, p = 0.009). There was no difference in rcFlow between both groups and between the points in time prior and after surgery. Neonates undergoing cardiac surgery suffer from peri-operative changes in hemodynamics and cerebral hypoxemic stress. The cerebral oxygen metabolism seems to be more affected in cyanotic children with functionally univentricular hearts compared to post-operative acyanotic patients. Additional stress factors must be avoided to achieve the best possible neurological outcome.

Cerebral Oxygen Metabolism Before and After RBC Transfusion in Infants Following Major Surgical Procedures

OBJECTIVE

Although infants following major surgery frequently require RBC transfusions, there is still controversy concerning the best definition for requirement of transfusion in the individual patient. The aim of this study was to determine the impact of RBC transfusion on cerebral oxygen metabolism in noncardiac and cardiac postsurgical infants.

DESIGN

Prospective observational cohort study.

SETTING

Pediatric critical care unit of a tertiary referral center.

PATIENTS

Fifty-eight infants (15 after pediatric surgery and 43 after cardiac surgery) with anemia requiring RBC transfusion were included.

INTERVENTIONS

RBC transfusion.

MEASUREMENTS AND MAIN RESULTS

We measured noninvasively regional cerebral oxygen saturation and microperfusion (relative cerebral blood flow) using tissue spectrometry and laser Doppler flowmetry before and after RBC transfusion. Cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen were calculated. Fifty-eight RBC transfusions in 58 patients were monitored (15 after general surgery, 24 after cardiac surgery resulting in acyanotic biventricular physiology and 19 in functionally univentricular hearts including hypoplastic left heart following neonatal palliation). The posttransfusion hemoglobin concentrations increased significantly (9.7 g/dL vs 12.8 g/dL; 9.7 g/dL vs 13.8 g/dL; 13.1 g/dL vs 15.6 g/dL; p < 0.001, respectively). Posttransfusion cerebral oxygen saturation was significantly higher than pretransfusion (61% [51-78] vs 72% [59-89]; p < 0.001; 58% [35-77] vs 71% [57-88]; p < 0.001; 51% [37-61] vs 58% [42-73]; p = 0.007). Cerebral fractional tissue oxygen extraction decreased posttransfusion significantly 0.37 (0.16-0.47) and 0.27 (0.07-039), p = 0.002; 0.40 (0.2-0.62) vs 0.26 (0.11-0.57), p = 0.001; 0.42 (0.23-0.52) vs 0.32 (0.1-0.42), p = 0.017. Cerebral blood flow and approximated cerebral metabolic rate of oxygen showed no significant change during the observation period. The increase in cerebral oxygen saturation and the decrease in cerebral fractional tissue oxygen extraction were most pronounced in patients after cardiac surgery with a pretransfusion cerebral fractional tissue oxygen extraction greater than or equal to 0.4.

CONCLUSION

Following RBC transfusion, cerebral oxygen saturation increases and cerebral fractional tissue oxygen extraction decreases. The data suggest that cerebral oxygenation in postoperative infants with cerebral fractional tissue oxygen extraction greater than or equal to 0.4 may be at risk in instable hemodynamic or respiratory situations.