The effect of continuous PEEP administration during surfactant instillation on cerebral hemodynamics in intubated preterm infants: a NIRS study

Objective: There is an ongoing debate about the best and comfortable way to administer surfactant. We hypothesized that uninterrupted respiratory support and continuous PEEP implementation while instilling surfactant via endotracheal tube (ETT) with side port will result in higher regional cerebral tissue oxygenation (rcSO2) and the alterations in cerebral hemodynamics will be minimal. Methods: Preterm infants who required intubation in the delivery room and/or in the first 24 hours of life with gestational age <32 were enrolled. Patients were intubated either via conventional ETT or ETT with side port (Vygon®) with appropriate sizes. Following NICU admission a NIRS probe placed on the forehead and each infant started to monitored with NIRS.In conventional ETT group, patients separated from the ventilator while surfactant was instilled. In ETT with side port group respiratory support was not interrupted during instillation. Heart rate, oxygen saturations, rcSO2, cerebral fractional tissue oxygen extraction (cFTOE) and blood pressures were recorded. Results: A total of 46 infants analyzed. Surfactant was instilled with conventional ETT in 23 and ETT with side port in 23 infants. Birth weights (1037±238 vs 1152±277g) and gestational ages (28±2.3 vs 29±1.6weeks) did not differ between groups. During instillation of surfactant, rcSO2 levels [61.5 (49-90) vs 70 (48-85)] and cFTOE levels 0.28 (0.10-0.44) vs 0.23 (0.03-0.44)] were similar (p=0.58 and 0.82 respectively). Conclusion: Interruption of respiratory support during surfactant instillation did not significantly alter the cerebral tissue oxygenation. These results did not support our hypothesis and should be confirmed with further studies.

The Behavioral Problems in 2.5–5 Years Old Children Linked with Former Neonatal/Infantile Surgical Parameters

Studies report the link between exposure to major neonatal surgery and the risk of later neurodevelopmental disorders. The aim of this study was to find out the behavioral problem scores of 2.5–5 years old children who had undergone median/major non-cardiac surgery before the age of 90 days, and to relate these to intraoperative cerebral tissue oxygenation values (rSO2), perioperative duration of mechanical ventilation (DMV) and doses of sedative/analgesic agents. Internalizing (IP) and externalizing problems (EP) of 34 children were assessed using the CBCL for ages 1½–5. Median (range) IP and EP scores were 8.5 (2–42) and 15.5 (5–33), respectively and did not correlate with intraoperative rSO2. DMV correlated and was predictive for EP (β (95% CI) 0.095 (0.043; 0.148)). An aggregate variable “opioid dose per days of ventilation” was predictive for EP after adjusting for patients’ gestational age and age at the day of psychological assessment, after further adjustment for age at the day of surgery and for cumulative dose of benzodiazepines (β (95% CI 0.009 (0.003; 0.014) and 0.008 (0.002; 0.014), respectively). Neonatal/infantile intraoperative cerebral oxygenation was not associated with later behavioral problems. The risk factors for externalizing problems appeared to be similar to the risk factors in preterm infant population.

Effect of aging on cerebral tissue oxygenation in relation to reflex syncope

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Swedish Heart and Lung Foundation, The Swedish Heart and Lung Association, ALF funds, Skåne University Hospital Funds, The Crafoord Foundation. Background There is an increased susceptibility to syncope with aging attributed to age-related physiological impairments. Cerebral oximetry non-invasively measures cerebral tissue oxygenation (SctO2) and has been shown to be valuable in syncope evaluation. SctO2 has been found to decrease with aging but it is unknown whether the decrease in SctO2 is related to increased susceptibility to syncope during orthostatic provocation. By measuring SctO2 during head up tilt test (HUT) we can study age-related differences in SctO2 and their impact on developing reflex syncope. Purpose To investigate the effect of age on the cerebral tissue oxygenation threshold for syncope and presyncope among patients with vasovagal syncope. Methods Non-invasive haemodynamic monitoring and near-infrared spectroscopy (NIRS) were applied during head-up tilt (HUT) in 139 vasovagal syncope patients (mean [SD] 45[17] years, 60% female), and 82 control patients with a normal response to HUT (45[18] years, 61% female). Group differences in SctO2 and systolic blood pressure (SBP) during HUT in supine position, after 3 and 10 min of HUT, 30 seconds prior to syncope ("presyncopal phase") and during syncope in different age groups (&lt;30, 30-60 and &gt;60 years) were compared using one-way ANOVA and Tukey"s multiple comparison test. Associations between age and SctO2 were studied using linear regression models adjusted for sex and concurrent SBP. Results Lower SctO2 in supine position was associated with increasing age among controls (B=-0.085, p = 0.010) but not among VVS patients (B=-0.036, p = 0.114). No age-related differences in SctO2 were found after 3 and 10 minutes of HUT and during syncope. Mean SctO2 (%) during the presyncopal phase decreased over the advancing age groups (&lt;30: 66.9 ± 6.2, 30-60: 64.5 ± 6.1, &gt;60: 62.2 ± 5.8; p = 0.009 for inter-group comparison). In contrast, mean SBP during the presyncopal phase did not differ by age groups (&lt;30: 85.6 ± 21.8, 30-60: 77.6 ± 19.7, &gt;60: 77.6 ± 20.8 mmHg, p = 0.133). Age was associated with lower SctO2 during the presyncopal phase after adjusting for sex and SBP (B = 0.096, p = 0.001). Conclusion Older VVS patients have lower cerebral tissue oxygenation in the presyncopal phase compared with younger patients independently of systolic blood pressure. These results suggest either that with imminent reflex syncope cerebral tissue oxygenation diminishes more with advancing age or that cerebral deoxygenation is better tolerated by older reflex syncope patients. Abstract Figure.

Comparison of renal region, cerebral and peripheral oxygenation for predicting postoperative renal impairment after CABG

Patients undergoing coronary artery bypass grafting (CABG) are at risk of developing postoperative renal impairment, amongst others caused by renal ischemia and hypoxia. Intra-operative monitoring of renal region tissue oxygenation (SrtO2) might be a useful tool to detect renal hypoxia and predict postoperative renal impairment. Therefore, the aim of this study was to assess the ability of intra-operative SrtO2 to predict postoperative renal impairment, defined as an increase of serum creatinine concentrations of > 10% from individual baseline, and compare this with the predictive abilities of peripheral and cerebral tissue oxygenation (SptO2 and SctO2, respectively) and renal specific tissue deoxygenation. Forty-one patients undergoing elective CABG were included. Near-infrared spectroscopy (NIRS) was used to measure renal region, peripheral (thenar muscle) and cerebral tissue oxygenation during surgery. Renal region specific tissue deoxygenation was defined as a proportionally larger decrease in SrtO2 than SptO2. ROC analyses were used to compare predictive abilities. We did not observe an association between tissue oxygenation measured in the renal region and cerebral oxygenation and postoperative renal impairment in this small retrospective study. In contrast, SptO2 decrease > 10% from baseline was a reasonable predictor with an AUROC of 0.767 (95%CI 0.619 to 0.14; p = 0.010). Tissue oxygenation of the renal region, although non-invasively and continuously available, cannot be used in adults to predict postoperative renal impairment after CABG. Instead, peripheral tissue deoxygenation was able to predict postoperative renal impairment, suggesting that SptO2 provides a better indication of ‘general’ tissue oxygenation status.Registered at ClinicalTrials.gov: NCT01347827, first submitted April 27, 2011.