Postoperative EEG abnormalities in relation to neurodevelopmental outcomes after pediatric cardiac surgery.

BACKGROUND: We had reported that postoperative EEG background including sleep-wake cycle (SWC) and discharge (seizures, spikes/sharp waves) abnormalities were significantly correlated with adverse early outcomes in children after cardiac surgery. We aimed to analyze the relations between these EEG abnormalities and neurodevelopmental outcomes at about 2 years after cardiac surgery. METHODS: We enrolled 121 patients undergoing cardiac surgery at 3.3 months (0.03 ~ 28 months). EEG abnormalities described above during the first postoperative 48 h were evaluated. Griffiths Mental Development Scales-Chinese was used to evaluate the quotients of overall development and 5 subscales of the child's locomotor, language, personal-social, eye-hand coordination and performance skills at 16 ~ 31 months of age. RESULTS: EEG background abnormalities occurred in 59/121 (48.8%) patients and 33 (55.9%) unrecovered to normal by 48 h. Abnormal SWC occurred in 15 (12.4%) patients and 7 (5.8%) unrecovered to normal by 48 h. EEG seizures occurred in 11 (9.1%) patients with frontal lobe seizures in 4. Spikes/sharp waves occurred in 100 (82.6%). EEG background abnormalities, number of spikes/sharp waves and frontal lobe seizures were significantly associated with neurodevelopmental impairment at about 1 ~ 2 year after surgery (Ps ≤ 0.05). CONCLUSIONS: Most parameters of EEG abnormalities were significantly associated with neurodevelopmental impairment after cardiac surgery. IMPACT: Neurodevelopmental impairment in children with congenital heart disease remain poorly understood. Previous studies had reported that either EEG seizures or background abnormalities were associated with worse neurodevelopmental outcomes. Our present study showed that all the EEG background and discharge abnormalities including EEG background, seizures and spikes/sharp waves in the early postoperative period were significantly associated with neurodevelopmental impairment at about 1 ~ 2 years after cardiac surgery. Comprehensive evaluation of early postoperative EEG may provide further insights about postoperative brain injury, its relation with neurodevelopmental impairment, and guide to improve clinical management.

The novel and slowest arterial pressure waves: clinical implications in children with congenital heart disease following cardiovascular surgery.

OBJECTIVES: Certain rhythmic arterial pressure waves in humans and animals have been noticed for over one century. We found the novel and slowest arterial pressure waves in children following surgical repair for CHD, and examined their characteristics and clinical implications. METHODS: We enrolled 212 children with 22 types of CHD within postoperative 48 h. We monitored haemodynamics (blood pressure, cardiac cycle efficiency, dP/dTmax), cerebral (ScO2), and renal (SrO2) oxygen saturation every 6 s. Electroencephalogram was continuously monitored. Mean blood flow velocity (Vm) of the middle cerebral artery was measured at 24 h. RESULTS: We found the waves with a frequency of ∼ 90 s immediately following surgical repair in 46 patients in 12 types of CHD (21.7%), being most prevalent in patients with aortic arch abnormalities (Aorta Group, n = 24, 42.3%) or ventricular septal defect (Ventricular Septal Defect Group, n = 12, 23.5%). In Aorta and Ventricular Septal Defect Groups, the occurrence of the waves was associated with lower blood pressures, dP/dTmax, cardiac cycle efficiency, ScO2, SrO2, Vm, worse electroencephalogram background abnormalities, higher number of electroencephalogram sharp waves, and serum lactate (Ps <0.0001-0.07), and were accompanied with fluctuations of ScO2 and SrO2 in 80.6% and 69.6% of patients, respectively. CONCLUSIONS: The waves observed in children following cardiovascular surgery are the slowest ever reported, occurring most frequently in patients with aortic arch abnormalities or ventricular septal defect. While the occurrence of the waves was associated with statistically worse and fluctuated ScO2 and SrO2, worse systemic haemodynamics, and electroencephalogram abnormalities, at present these waves have no known clinical relevance.

Perioperative EEG background and discharge abnormalities in children undergoing cardiac surgery: a prospective single-centre observational study.

BACKGROUND: We analysed the characteristics of abnormal electroencephalogram (EEG) patterns before, during, and 48 h after cardiac surgery in patients with heterogeneous congenital heart disease to assess their relationship to demographic and perioperative variables and to early patient outcomes. METHODS: In 437 patients enrolled in a single centre, EEG was evaluated for background (including sleep-wake cycle) and discharge (seizures, spikes/sharp waves, pathological delta brushes) abnormalities. Clinical data (arterial blood pressure, doses of inotropic drugs, and serum lactate concentrations) were recorded every 3 h. Postoperative brain MRI was performed before discharge. RESULTS: Preoperative, intraoperative, and postoperative EEG was monitored in 139, 215, and 437 patients, respectively. Patients with a degree of preoperative background abnormalities (n=40) had more severe intraoperative and postoperative EEG abnormalities (P<0.0001). Intraoperatively, 106/215 (49.3%) patients progressed into an isoelectric EEG. Longer durations of isoelectric EEG were associated with more severe postoperative EEG abnormalities and brain injury on MRI (Ps≤0.003). Postoperative background abnormalities occurred in 218/437 (49.9%) patients, and 119 (54.6%) of them had not recovered after surgery. Seizures occurred in 36/437 (8.2%) patients, spikes/sharp waves in 359/437 (82.2%), and pathological delta brushes in 9/437 (2.0%). Postoperative EEG abnormalities correlated with degree of brain injury on MRI (Ps≤0.02). Demographic and perioperative variables were significantly correlated with postoperative EEG abnormalities, which in turn correlated with adverse clinical outcomes. CONCLUSIONS: Perioperative EEG abnormalities occurred frequently and correlated with numerous demographic and perioperative variables and adversely correlated with postoperative EEG abnormalities and early outcomes. The relation of EEG background and discharge abnormalities with long-term neurodevelopmental outcomes remains to be explored.

Characteristics of neonatal hypoxic-ischemic encephalopathy at high altitude and early results of therapeutic hypothermia.

BACKGROUND: Altitude hypoxia and limited socioeconomic conditions may result in distinctive features of neonatal hypoxic-ischemic encephalopathy (HIE). Therapeutic hypothermia (TH) has not been used at altitude. We examined characteristics of HIE and early outcomes of TH in 3 centers at two high altitudes, 2 at 2,261 m and 1 at 3,650 m. METHODS: The incidence of HIE at NICUs was noted. TH was conducted when personnel and devices were available in 2019~2020. Standard inclusion criteria were used, with the addition of admission age >6 hours and mild HIE. Demographic and clinical data included gestational age, gender, weight, Apgar score, ethnics, age on admission, age at TH and clinical degree of HIE. EEG was monitored for 96 hours during hypothermia and rewarming. MRI was performed before discharge. RESULTS: There was significant difference in ethnics, HIE degree, age at TH across 3 centers. The overall NICU incidence of HIE was 4.0%. Among 566 HIE patients, 114 (20.1%) received TH. 63 (55.3%) patients had moderate/severe HIE. Age at TH >6 hours occurred in 34 (29.8%) patients. EEG discharges showed seizures in 7~11% of patients, whereas spikes/sharp waves in 94~100%, delta brushes in 50~100%. After TH, MRI showed moderate to severe brain injury in 77% of patients, and correlated with center, demographic and clinical variables (Ps≤0.0003). Mortality was 5% during hospitalization and 11% after discharge until 1 year. CONCLUSIONS: At altitude, the incidence of HIE was high and brain injury was severe. TH was limited and often late >6 hours. EEG showed distinct patterns attributable to altitude hypoxia. TH was relatively safe. TRIAL REGISTRATION: The study was registered on February 23, 2019 in Chinese Clinical Trial Register (ChiCTR1900021481).

Distinct profiles of cerebral oxygenation in focal vs. secondarily generalized EEG seizures in children undergoing cardiac surgery.

Objectives: Seizures are common in children undergoing cardiopulmonary bypass (CPB). Cerebral oxygen saturation (ScO2) by near-infrared spectroscopy is routinely monitored in many centers, but the relations between the levels and changes of ScO2 and brain injuries remain incompletely understood. We aimed to analyze the postoperative profiles of ScO2 and cerebral blood flow velocity in different types of EEG seizures in relation to brain injuries on MRI. Methods: We monitored continuous EEG and ScO2 in 337 children during the first 48 h after CPB, which were analyzed in 3 h periods. Cerebral blood flow peak systolic velocity (PSV) in the middle cerebral artery was measured daily by transcranial Doppler. Postoperative cerebral MRI was performed before hospital discharge. Results: Based on the occurrence and spreading types of seizures, patients were divided into three groups as patients without seizures (Group N; n = 309), those with focal seizures (Group F; n = 13), or with secondarily generalized seizures (Group G; n = 15). There were no significant differences in the onset time and duration of seizures and incidence of status epilepticus between the two seizures groups (Ps ≥ 0.27). ScO2 increased significantly faster across Group N, Group G, and Group F during the 48 h (p < 0.0001) but its overall levels were not significantly different among the three groups (p = 0.30). PSV was significantly lower (p = 0.003) but increased significantly faster (p = 0.0003) across Group N, Group G, and Group F. Group F had the most severe brain injuries and the highest incidence of white matter injuries on MRI among the three groups (Ps ≤ 0.002). Conclusion: Postoperative cerebral oxygenation showed distinct profiles in secondarily generalized and particularly focal types of EEG seizures in children after CPB. A state of 'overshooting' ScO2 with persistently low PSV was more frequently seen in those with focal seizures and more severe brain injury. Information from this study may have important clinical implications in detecting brain injuries when monitoring cerebral oxygenation in this vulnerable group of children after CPB.

Cerebral Autoregulation Status in Relation to Brain Injury on Electroencephalogram and Magnetic Resonance Imaging in Children Following Cardiac Surgery.

Background Disturbed cerebral autoregulation has been reported in children with congenital heart disease before and during cardiopulmonary bypass surgery, but not after. We sought to characterize the cerebral autoregulation status in the early postoperative period in relation to perioperative variables and brain injuries. Methods and Results A prospective and observational study was conducted in 80 patients in the first 48 hours following cardiac surgery. Cerebral oximetry/pressure index (COPI) was retrospectively calculated as a moving linear correlation coefficient between mean arterial blood pressure and cerebral oxygen saturation. Disturbed autoregulation was defined as COPI >0.3. Correlations of COPI with demographic and perioperative variables as well as brain injuries on electroencephalogram and magnetic resonance imaging and early outcomes were analyzed. Thirty-six (45%) patients had periods of abnormal COPI for 7.81 hours (3.38 hours) either at hypotension (median <45 mm Hg) or hypertension (median >90 mm Hg) or both. Overall, COPI became significantly lower over time, suggesting improved autoregulatory status during the 48 postoperative hours. All of the demographic and perioperative variables were significantly associated with COPI, which in turn was associated with the degree of brain injuries and early outcomes. Conclusions Children with congenital heart disease following cardiac surgery often have disturbed autoregulation. Cerebral autoregulation is at least partly the underlying mechanism of brain injury in those children. Careful clinical management to manipulate the related and modifiable factors, particularly arterial blood pressure, may help to maintain adequate cerebral perfusion and reduce brain injury early after cardiopulmonary bypass surgery. Further studies are warranted to determine the significance of impaired cerebral autoregulation in relation to long-term neurodevelopment outcomes.

Postoperative hypernatremia is associated with worse brain injuries on EEG and MRI following pediatric cardiac surgery.

Objectives: Dysnatremia is a common electrolyte disturbance after cardiopulmonary bypass (CPB) surgery for congenital heart disease (CHD) and a known risk factor for adverse neurological events and clinical outcomes. The objective of this study was to evaluate the association of dysnatremia with worse abnormal EEG patterns, brain injuries detected by magnetic resonance imaging (MRI) and early adverse outcomes. Methods: We monitored continuous EEG in 340 children during the initial 48 h following cardiac surgery. Demographics and clinical characteristics were recorded. Sodium concentrations were measured in the arterial blood gas analysis every 6 h. Hyponatremia and hypernatremia were classified by the average of sodium concentrations over 48 h. Postoperative cerebral MRI was performed before hospital discharge. Results: In our patient cohort, dysnatremia was present in 46 (13.5%) patients. Among them, hyponatremia occurred in 21 (6.2%) and hypernatremia in 25 (7.4%). When compared to patients with normonatremia, hyponatremia was not associated with EEG abnormalities and early adverse outcomes (Ps ≥ .14). In hypernatremia group, the CPB time was significantly longer and more frequent use of DHCA (Ps ≤ .049). After adjusting for time, CPB time and the use of DHCA, hypernatremia was significantly associated with worse EEG abnormalities (including background, seizures and pathological delta brushes), more severe brain injuries on MRI (Ps ≤ .04) and trended to be associated with longer postoperative mechanical ventilation time (P = .06). Conclusion: Hypernatremia and hyponatremia were common in children after cardiac surgery. Hypernatremia, but not hyponatremia, was significantly associated with worse EEG abnormalities and more severe brain injuries on MRI and extended postoperative mechanical ventilation time.

Assessment of postoperative risk factors for EEG abnormalities in routine clinical management after paediatric cardiopulmonary bypass.

OBJECTIVES: The postoperative risk factors for electroencephalogram(EEG) abnormalities after paediatric cardiopulmonary bypass (CPB) remain to be identified. We investigated the characteristics of EEG abnormalities and risk factors in routine clinical management post-CPB. METHODS: EEG and cerebral oxygen saturation (ScO2) were monitored in 96 patients (aged 3 days, 37 months, median 5 months) for 72 h post-CPB. Clinical measurements included 4-hourly arterial and central venous pressure, arterial blood gases, doses of inotropic and vasoactive drugs, daily C-reactive protein (CRP) and NT-proB-type Natriuretic Peptide (NT-proBNP). Demographics, STAT categories and outcomes (duration of mechanical ventilation,CICU stay) were recorded. Un. RESULTS: Seizures occurred in 20 patients (20.8%) beginning at 0-48 hand lasting 10 min-31 h; background abnormalities occurred in 67 (69.8%) beginning at 0-8 h and lasting 4-48 h. Patients with EEG abnormalities had worse outcomes. In univariable regression, seizures positively correlated with STAT categories, CPB time, temperature, blood pressure, central venous pressure, NT-proBNP, CRP, lactate and epinephrine, negatively with ScO2 and PaCO2 (P < 0.001 for lactate and epinephrine, P < 0.1 for the remaining). The degree of background abnormalities positively correlated with STAT categories, CPB time, operative time, central venous pressure, milrinone, negatively with blood pressure (P = 0.0003-0.087); it negatively correlated with lower dose of epinephrine (P < 0.001) and positively with higher dose (P = 0.03l). In multivariable regression, seizures positively correlated with epinephrine, lactate and temperature; the background abnormality correlations remain significant except for milrinone and operative time (P < 0.001 for epinephrine, P < 0.05 for the remaining). CONCLUSIONS: Numerous perioperative risk factors are associated with EEG abnormalities post-CPB. The most significant and consistent risk factor is epinephrine.