Effects of different ventilation on cerebral oxygen saturation and cerebral blood flow before and after modified ultrafiltration in infants during ventricular septal defect repair.

OBJECTIVE: To analyse the changes of different ventilation on regional cerebral oxygen saturation and cerebral blood flow in infants during ventricular septal defect repair. METHODS: Ninety-two infants younger than 1 year were enrolled in the study. End-expiratory tidal pressure of carbon dioxide was maintained at 40-45 and 35-39 mmHg in relative low and high ventilation groups. Regional cerebral oxygen saturation and flow velocity of the middle cerebral artery were recorded after anaesthesia (T0), cut pericardium (T1), separation from cardiopulmonary bypass (T2), the end of modified ultrafiltration, (T3) and at the end of operation (T4). RESULTS: The relative low ventilation group exhibited a significantly high regional cerebral oxygen saturation at each time point except for T2 (T0:77 ± 4, T1:76 ± 5, T3:76 ± 8, T4:76 ± 8, respectively, p < 0.001). Flow velocity of the middle cerebral artery in the relative low ventilation group was higher compared to the relative high ventilation group at each time point except for T2 (T0:53 ± 14, T1:54 ± 15, T3:53 ± 17, T4:52 ± 16, respectively, p < 0.001). Between the two groups, T2 showed the lowest middle cerebral artery flow velocity (relative low ventilation: 39 ± 15, relative high ventilation: 39 ± 11, p < 0.001). CONCLUSION: The infants' regional cerebral oxygen saturation and middle cerebral artery flow velocity performed better in the range of 40-45 mmHg end-expiratory tidal pressure of carbon dioxide during CHD surgery. Modified ultrafiltration increased cerebral oxygen saturation. It was important to regulate ventilation in order to balance cerebral oxygen in infants.

Prognostic value of cardiac cycle efficiency in children undergoing cardiac surgery: a prospective observational study.

BACKGROUND: Cardiac cycle efficiency (CCE) derived from a pressure-recording analytical method is a unique parameter to assess haemodynamic performance from an energetic view. This study investigated changes of CCE according to an anatomical diagnosis group, and its association with early postoperative outcomes in children undergoing cardiac surgery. METHODS: Ninety children were included with a ventricular septal defect (VSD; n=30), tetralogy of Fallot (TOF; n=40), or total anomalous pulmonary venous connection (TAPVC; n=20). CCE along with other haemodynamic parameters, was recorded from anaesthesia induction until 48 h post-surgery. Predictive CCE (CCEp) was defined as the average of CCE at post-modified ultrafiltration and CCE at the end of surgery. The relationship between CCE and early outcomes was assessed by the comparison between the high-CCEp group (CCEp ≥75th centile) and the low-CCEp group (CCEp ≤25th centile). RESULTS: There was a significant time × diagnostic group interaction effect in the trend of CCE. Compared with the high-CCEp group (n=23), the low-CCEp group (n=22) required more inotropics post-surgery, had higher lactate concentrations at 8 and 24 h post-surgery, a longer intubation time and longer ICU stay, and higher frequency of peritoneal fluid. CONCLUSIONS: Perioperative changes of CCE vary according to anatomical diagnosis in children undergoing cardiac surgery. Children with TOF have an unfavourable trend of CCE compared with children with VSD or TAPVC. A decline in CCE is associated with adverse early postoperative outcomes. CLINICAL TRIAL REGISTRATION: ChiCTR1800014996.

Effect of End-Tidal Carbon Dioxide on Cerebral Dynamics in Infants With Ventricular Septal Defect: A Comparison Between Sevoflurane and Intravenous Anesthetics.

OBJECTIVES: The primary aim was to compare the changes in regional cerebral oxygen saturation (rSO2) and cerebral blood flow velocity (CBFV) during sevoflurane and intravenous anesthesia when the end-tidal carbon dioxide partial pressure (PETCO2) changed in infants undergoing ventricular septal defect (VSD) repair. DESIGN: Prospective, observational study. SETTING: Tertiary care hospital. PARTICIPANTS: Patients younger than 6 months with VSDs. INTERVENTIONS: End-tidal carbon dioxide was increased by decreasing tidal volume or respiratory rate. MEASUREMENTS AND MAIN RESULTS: The infants were randomly assigned to receive either sevoflurane (SA group) or midazolam-sufentanil based intravenous anesthesia (IA group). PETCO2 levels of 30 mmHg (T1), 35 mmHg (T2), 40 mmHg (T3), or 45 mmHg (T4) were obtained by adjusting the tidal volume and respiratory rate. There were no significant intergroup differences in rSO2. In the SA group, as PETCO2 increased from T1 to T4, rSO2 increased significantly from 68.8% ± 5.9% to 76.4% ± 6.0% (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). In the IA group, rSO2 showed a significant increase from 68.6% ± 4.6% to 76.1% ± 6.2% with the change in PETCO2 from T1 to T4 (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). CONCLUSION: Cerebrovascular response to different PETCO2 levels was preserved and similar during clinically relevant doses of sevoflurane anesthesia and midazolam-sufentanil based intravenous anesthesia in infants younger than 6 months old undergoing VSD repair.

Measuring Cerebral Carbon Dioxide Reactivity With Transcranial Doppler and Near-Infrared Spectroscopy in Children With Ventricular Septal Defect.

OBJECTIVE: Neurologic impairment is frequently observed in children with congenital heart disease. Impairment in cerebrovascular carbon dioxide reactivity (CO2R) is related with poor neurologic outcomes. The present study examined CO2R measured with transcranial Doppler (TCD) and near-infrared spectroscopy (NIRS) in children with ventricular septal defect undergoing cardiac surgery. DESIGN: Prospective, paired controlled study. SETTING: Operating room of a tertiary care center. PARTICIPANTS: Twenty children with ventricular septal defect and younger than 1 year were enrolled, and 17 children were studied (age: 6.0 ± 2.0 mo, weight 5.9 ± 1.0 kg). INTERVENTION: After induction of anesthesia and tracheal intubation, the lungs were ventilated and mechanical ventilation was initiated. Partial pressure of end-tidal carbon dioxide (PETCO2) was adjusted at 4 different levels (30, 35, 40, and 45 mmHg). MEASUREMENTS AND MAIN RESULTS: Paired measurements of middle cerebral artery mean blood flow velocity (VMCA) by TCD and tissue oxygen index (TOI) by NIRS were recorded at each level of PETCO2. CO2R was calculated as the percentage change of VMCA and TOI per mmHg change in PETCO2. Systemic hemodynamic parameters were recorded. As PETCO2 rose from 30 to 45 mmHg, VMCA and TOI increased linearly (p < 0.001 for both), and CO2R-TCD and CO2R-NIRS were calculated to be 2.8% ± 0.9%/mmHg and 1.2% ± 0.3 %/mmHg, respectively. CO2R-NIRS was significantly lower compared with CO2R-TCD (p < 0.001). Significant correlations were found between VMCA and TOI (r = 0.487; p < 0.001) and between ΔVMCA and ΔTOI (r = 0.693; p < 0.001), but not between CO2R-TCD and CO2R-NIRS (r = 0.18; p = 0.24). With the increase of PETCO2, cardiac index, systemic vascular resistance index, and mean arterial pressure remained constant (p > 0.05 for all) and the heart rate decreased significantly (p = 0.018). CONCLUSIONS: During anesthesia, CO2R remains preserved in children with a ventricular septal defect. Even though there is lack of correlation between CO2R-TCD and CO2R-NIRS, changes in TOI and VMCA were correlated as the PETCO2 changed. NIRS may be used as a surrogate to investigate CO2R when the ultrasound window is poor.

Age-related cerebrovascular carbon dioxide reactivity in children with ventricular septal defect younger than 3 years.

BACKGROUND: Impaired cerebrovascular reactivity to carbon dioxide was proposed to contribute to neurological morbidity in children undergoing cardiac surgery. The objective of this study was to assess carbon dioxide reactivity and regional cerebral oxygen saturation in children younger than 3 years. METHODS: This study enrolled children younger than 3 years undergoing ventricular septal defect repair. The cohort was divided into three age groups: younger than 6 months, 6-12 months, and 12-36 months. Under steady-state anesthesia, carbon dioxide reactivity was calculated by measuring changes in middle cerebral artery blood flow velocity using transcranial Doppler sonography. Regional cerebral oxygen saturation changes were measured by near-infrared spectroscopy while endtidal carbon dioxide pressure was adjusted from 30 to 45 mm Hg. RESULTS: Carbon dioxide reactivity showed a statistically significant increasing relationship with age (younger than 6 months group: 4.42% ± 2.73%, 6-12 months group: 5.86% ± 1.91%, 12-36 months group: 7.58% ± 1.49%; P < .001). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with age (younger than 6 months group: 65% ± 6%, 6-12 months group: 68% ± 5%, 12-36 months group: 70% ± 5%; P = .027). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with endtidal carbon dioxide pressure in all children (P < .001). CONCLUSION: Abnormal carbon dioxide reactivity is prevalent in children younger than 3 years and the degree varies according to age.

The Organ-Protective Effect of Higher Partial Pressure of Arterial Carbon Dioxide in the Normal Range for Infant Patients Undergoing Ventricular Septal Defect Repair.

Hypercapnia has been reported to play an active role in protection against organ injury. The aim of this study was to determine whether a higher level of partial pressure of arterial carbon dioxide (PaCO2) within the normal range in pediatric patients undergoing cardiac surgery had a similar organ-protective effect. From May 2017 to May 2018, 83 consecutive infant patients undergoing ventricular septal defect (VSD) repair with cardiopulmonary bypass were retrospectively enrolled. We recorded the end-expiratory tidal partial pressure of carbon dioxide (Pet-CO2) as an indirect and continuous way to reflect the PaCO2. The patients were divided into a low PaCO2 group (LPG; 30 mmHg < Pet-CO2 < 40 mmHg) and a high PaCO2 group (HPG; 40 mmHg < Pet-CO2 < 50 mmHg). The regional cerebral oxygen saturation (rScO2), cerebral blood flow velocity (CBFV), and hemodynamics at five time points throughout the operation, and perioperative data were recorded and analyzed for the two groups. In total, 34 LPG and 49 HPG patients were included. Demographics and perioperative clinical data showed no significant difference between the groups. Compared with LPG, the HPG produced lower postoperative creatine kinase isoenzyme-MB (40.88 versus 50.34 ng/mL, P = 0.038). The postoperative C-reactive protein of HPG trended lower than in LPG (61.09 versus 73.4 mg/L, P = 0.056). The rScO2 and mean CBFV of HPG were significantly higher compared with LPG (P < 0.05) except at the end of cardiopulmonary bypass. Hemodynamic data showed no significant difference between the groups. As a convenient and safe approach, higher-normal PaCO2 could attenuate brain injury, heart injury, and inflammatory response in infant patients undergoing VSD repair.

Effects of relative low minute ventilation on cerebral haemodynamics in infants undergoing ventricular septal defect repair.

BACKGROUND: Ventilation-associated changes in blood carbon dioxide levels are associated with various physiological changes in infants undergoing surgery. Studies on the effects of mechanical ventilation on cerebral haemodynamics especially for infants with CHD are scarce. AIM: This study was done to compare the changes in regional cerebral oxygen saturation and cerebral blood flow velocity when the end-tidal carbon dioxide partial pressure changed during different minute ventilation settings in infants undergoing ventricular septal defect repair. METHODS: A total of 67 patients less than 1 year old with ventricular septal defect were enrolled, and 65 patients (age: 6.7 ± 3.4 months, weight: 6.4 ± 1.5 kg) were studied. After anaesthesia induction and endotracheal intubation, the same mechanical ventilation mode (The fraction of inspired oxygen was 50%, and the inspiratory-to-expiratory ratio was 1:1.5.) was adopted. The end-tidal carbon dioxide partial pressure of 30 mmHg (T1), 35 mmHg (T2), 40 mmHg (T3), or 45 mmHg (T4) were obtained, respectively, by adjusting tidal volume and respiratory rate. Minute ventilation per kilogram was calculated by the formula: minute ventilation per kilogram = tidal volume * respiratory rate/kg. Regional cerebral oxygen saturation was monitored by real-time near-infrared spectroscopy. Cerebral blood flow velocity (systolic flow velocity, end-diastolic flow velocity, and mean flow velocity), pulsatility index, and resistance index were measured intermittently by transcranial Doppler. Systolic pressure, diastolic pressure, stroke volume index, and cardiac index were recorded using the pressure recording analytical method. RESULTS: As the end-tidal carbon dioxide partial pressure increased from 30 to 45 mmHg, regional cerebral oxygen saturation increased significantly from 69 ± 5% to 79 ± 4% (p < 0.001). Cerebral blood flow velocity (systolic flow velocity, end-diastolic flow velocity, and mean flow velocity) increased linearly, while pulsatility index and resistance index decreased linearly from T1 (systolic flow velocity, 84 ± 19 cm/second; end-diastolic flow velocity, 14 ± 4 cm/second; mean flow velocity, 36 ± 10 cm/second; pulsatility index, 2.13 ± 0.59; resistance index, 0.84 ± 0.12) to T4 (systolic flow velocity, 113 ± 22 cm/second; end-diastolic flow velocity, 31 ± 6 cm/second; mean flow velocity, 58 ± 11 cm/second; pulsatility index, 1.44 ± 0.34; resistance index, 0.72 ± 0.07) (p < 0.001). There were significant differences in changes of systolic flow velocity, end-diastolic flow velocity, mean flow velocity, pulsatility index, and resistance index as the end-tidal carbon dioxide partial pressure increased from 30 to 45 mmHg between subgroups of infants ≤6 and infants >6 months, while the changes of regional cerebral oxygen saturation between subgroups were not statistically different. Regional cerebral oxygen saturation and cerebral blood flow velocity (systolic flow velocity, end-diastolic flow velocity, and mean flow velocity) were negatively correlated with minute ventilation per kilogram (r = -0.538, r = -0.379, r = -0.504, r = -0.505, p < 0.001). Pulsatility index and resistance index were positively related to minute ventilation per kilogram (r = 0.464, r = 0.439, p < 0.001). The diastolic pressure was significantly reduced from T1 (41 ± 7 mmHg) to T4 (37 ± 6 mmHg) (p < 0.001). There were no significant differences in systolic pressure, stroke volume index, and cardiac index with the change of end-tidal carbon dioxide partial pressure from T1 to T4 (p = 0.063, p = 0.382, p = 0.165, p > 0.05). CONCLUSION: A relative low minute ventilation strategy increases regional cerebral oxygen saturation and cerebral blood flow, which may improve cerebral oxygenation and brain perfusion in infants undergoing ventricular septal defect repair.

Comparison of sufentanil-midazolam and sevoflurane for anesthesia induction in children undergoing cardiac surgery by real-time hemodynamic and cardiac efficiency monitoring: A prospective randomized study.

Background Intravenous sufentanil-midazolam and inhalational sevoflurane are widely used for anesthetic induction in children undergoing cardiac surgery. However, knowledge about their effects on hemodynamics and cardiac efficiency remains limited due largely to the lack of direct monitoring method. We used minimally invasive technique pressure recording analytical method (PRAM) to directly monitor hemodynamics and cardiac efficiency and compared the effects of the two anesthetic regimens in children undergoing ventricular septal defect repair. Methods Forty-Four children (2.3±0.9 years) were randomly divided into two groups to receive either intravenous sufentanil (1 µg/kg) and midazolam (0.2 mg/kg) (Group SM) or 2.0 minimal alveolar concentration (MAC) sevoflurane (Group S) to complete induction after sedation was obtained with 2.0 MAC sevoflurane. Systemic hemodynamic data recorded by PRAM included heart rate (HR), systolic (SBP) and mean (MBP) blood pressure, stroke volume index (SVI), cardiac index (CI), systemic vascular resistance index (SVRI), the maximal slope of systolic upstroke (dp/dtmax) and cardiac cycle efficiency (CCE) after sedation obtained, 1, 2, 5 min after induction achieved, 1, 2, 5 and 10 min after intubation. Results HR, SVRI showed a decrease in Group SM but an increase in Group S (Ptime*group<0.0001) in the study period. SVI and CCE showed an increase in Group SM but a decrease in Group S (Ptime*group<0.0001). SBP, MBP and CI were related to time after polynomial transformation, and showed an increase after intubation in Group SM but a decrease in Group S (Ptime2*group<0.0001). Conclusion PRAM provides meaningful and direct monitoring of hemodynamics and cardiac efficiency during the dynamic period of anesthetic induction in children undergoing cardiac surgery. As compared to inhalational sevoflurane, intravenous sufentanil-midazolam exerts more favorable effects on systemic hemodynamics and cardiac efficiency during anesthetic induction in this group of patients.

Different predictivity of fluid responsiveness by pulse pressure variation in children after surgical repair of ventricular septal defect or tetralogy of Fallot.

BACKGROUND: Pulse pressure variation derived from the varied pulse contour method is based on heart-lung interaction during mechanical ventilation. It has been shown that pulse pressure variation is predictive of fluid responsiveness in children undergoing surgical repair of ventricular septal defect. Right ventricle compliance and pulmonary vascular capacitance in children with tetralogy of Fallot are underdeveloped as compared to those in ventricular septal defect. We hypothesized that the difference in the right ventricle-pulmonary circulation in the two groups of children would affect the heart-lung interaction and therefore pulse pressure variation predictivity of fluid responsiveness following cardiac surgery. METHODS: Infants undergoing complete repair of ventricular septal defect (n=38, 1.05±0.75 years) and tetralogy of Fallot (n=36, 1.15±0.68 years) clinically presenting with low cardiac output were enrolled. Fluid infusion with 5% albumin or fresh frozen plasma was administered. Pulse pressure variation was recorded using pressure recording analytical method along with cardiac index before and after fluid infusion. Patients were considered as responders to fluid loading when cardiac index increased ≥15%. Receiver operating characteristic curves analysis was used to assess the accuracy and cutoffs of pulse pressure variation to predict fluid responsiveness. RESULTS: The pulse pressure variation values before and after fluid infusion were lower in tetralogy of Fallot children than those in ventricular septal defect children (15.2±4.4% vs 19.3±4.4%, P<.001; 11.6±3.8 vs 15.4±4.3%, P<.001, respectively). In ventricular septal defect children, 27 were responders and 11 nonresponders. Receiver operating characteristic curve area was 0.89 (95% confidence interval, 0.77-1.01) and cutoff value 17.4% with a sensitivity of 0.89 and a specificity of 0.91. In tetralogy of Fallot children, 26 were responders and 10 were nonresponders. Receiver operating characteristic curve area was 0.79 (95% CI, 0.64-0.94) and cutoff value 13.4% with a sensitivity of 0.81 and a specificity of 0.80. CONCLUSION: Pulse pressure variation is predictive of fluid responsiveness in ventricular septal defect and tetralogy of Fallot patients following cardiac surgery.

Prediction of Fluid Responsiveness Using Pulse Pressure Variation in Infants Undergoing Ventricular Septal Defect Repair with Median Sternotomy or Minimally Invasive Right Thoracotomy.

Fluid management is challenging in infants after cardiopulmonary bypass. Pulse pressure variation (PPV) derived from pressure recording analytical method (PRAM) is based on lung-heart interaction during mechanical ventilation. A prospective observational study conducted in operating room tested PPV to predict fluid responsiveness in ventricular septal defect infants. Infants in open chest conditions with median sternotomy (n = 26) or minimally invasive right thoracotomy (n = 29) undergoing ventricular septal defect repair were enrolled. After cardiopulmonary bypass and modified ultrafiltration, all patients received fluid challenge. PPV was recorded using PRAM along with heart rate, diastolic blood pressure, stroke volume index (SVI), and cardiac index (CI) before and after volume replacement. Patients were considered as responders to fluid loading when CI increased ≥15%. In infants with median sternotomy, 12 were responders and 14 non-responders. PPV in responders was higher than that in non-responders (24.7 ± 6.4 vs. 16.6 ± 5.0%, P < 0.01). Area under the curve was 0.85 (95% confidence interval, 0.69-1, P = 0.001) and cutoff value 19% with a sensitivity of 92% and a specificity of 71%. In infants with minimally invasive right thoracotomy, 16 were responders and 13 non-responders. PPV in responders was higher than that in non-responders (25.0 ± 6.8 vs. 18.2 ± 5.3, P < 0.01). Area under the curve was 0.83 (95 confidence interval, 0.66-0.98, P = 0.001) and cutoff value 18% with a sensitivity of 94% and a specificity of 69%. PPV sensitively predicts fluid responsiveness in ventricular septal defect infants after surgical repair in open chest conditions both with median sternotomy and minimally invasive right thoracotomy.

Comparison of hemodynamic effects of sevoflurane and ketamine as basal anesthesia by a new and direct monitoring during induction in children with ventricular septal defect: A prospective, randomized research.

BACKGROUND: Sevoflurane and ketamine are commonly used to obtain sedation and facilitate intravenous anesthetic induction in children undergoing cardiac surgery who are uncooperative. We used a new and direct systemic hemodynamic monitoring technique pressure recording analytical method and compared the hemodynamic effects of sevoflurane and ketamine to facilitate intravenous anesthetic induction. METHODS: Forty-four children with ventricular septal defect (2.2 ±â€Š1.2 years) were enrolled and randomized to receive sevoflurane (Group S) or intramuscular ketamine (Group K) for sedation, followed by intravenous midazolam-sufentanil induction and tracheal intubation. Recorded parameters included heart rate (HR), arterial pressures, stroke volume index (SVI), cardiac index (CI), systemic vascular resistance index (SVRI), the maximal slope of systolic upstroke (dp/dtmax) after sedation obtained with sevoflurane or ketamine, 1, 2, 5 minutes after midazolam-sufentanil, 1, 2, 5, and 10 minutes after tracheal intubation. Rate-pressure product (RPP) and cardiac power output (CPO) were calculated. RESULTS: As compared with Group S, Group K had faster decreases during intravenous anesthetic induction in arterial pressures (P < .01 for all), higher HR, arterial pressures, SVRI, dp/dtmax, RPP, lower SVI, CI, CPO (P < .05 for all) during the study period. CONCLUSION: As compared with sevoflurane, ketamine facilitated intravenous anesthetic induction exerts unfavorable effects on systemic hemodynamic and myocardial energetic in children with ventricular septal defect.