The effect of pulsatile versus non-pulsatile flow during cardiopulmonary bypass on cerebral oxygenation: A randomized trial

Background The present study aims to compare regional oxygen supply determined by Near-Infrared Spectroscopy in the course of pulsatile perfusion with non-pulsatile perfusion during cardiopulmonary bypass in patients undergoing valvular heart surgery. Methods In this prospective randomized single-blinded trial, we enrolled adult subjects aged 18–65 years scheduled for elective valvular heart repair/replacement surgery with non-stenotic carotid arteries, employing a consecutive sampling method. Eligible patients were then randomly assigned in a 1:1 ratio to pulsatile or non-pulsatile perfusion during aortic cross-clamp. The primary outcome was regional cerebral oxygenation monitored by Near-Infrared Spectroscopy in each group. Results Seventy patients were randomly assigned, and each group comprised 35 patients. Mean age was 46.8 and 46.5 years in pulsatile and non-pulsatile groups, respectively. There were no significant between-group differences in regional cerebral oxygen saturation at different time points of cardiopulmonary bypass ( p-value for analysis of variance repeated measures: 0.923 and 0.223 for left and right hemispheres, respectively). Moreover, no significant differences in regional cerebral oxygen saturation levels from baseline between pulsatile and non-pulsatile groups at all desired time points for the left ( p = 0.51) and right ( p = 0.22) hemispheres of the brain were detected. Conclusion Pulsatile perfusion during cardiopulmonary bypass does not offer superior regional cerebral oxygenation measured by Near-Infrared Spectroscopy than non-pulsatile perfusion during cardiopulmonary bypass. Nonetheless, the efficacy of pulsatile flow in the subgroup of patients in whom cerebral blood flow is impaired due to carotid artery stenosis needs to be explored and evaluated by this method in future studies.

Comparison of the Effects of Normocapnia and Mild Hypercapnia on the Optic Nerve Sheath Diameter and Regional Cerebral Oxygen Saturation in Patients Undergoing Gynecological Laparoscopy with Total Intravenous Anesthesia

Cerebral hemodynamics may be altered by hypercapnia during a lung-protective ventilation (LPV), CO2 pneumoperitoneum, and Trendelenburg position during general anesthesia. The purpose of this study was to compare the effects of normocapnia and mild hypercapnia on the optic nerve sheath diameter (ONSD), regional cerebral oxygen saturation (rSO2), and intraoperative respiratory mechanics in patients undergoing gynecological laparoscopy under total intravenous anesthesia (TIVA). Sixty patients (aged between 19 and 65 years) scheduled for laparoscopic gynecological surgery in the Trendelenburg position. Patients under propofol/remifentanil total intravenous anesthesia were randomly assigned to either the normocapnia group (target PaCO2 = 35 mmHg, n = 30) or the hypercapnia group (target PaCO2 = 50 mmHg, n = 30). The ONSD, rSO2, and respiratory and hemodynamic parameters were measured at 5 min after anesthetic induction (Tind) in the supine position, and at 10 min and 40 min after pneumoperitoneum (Tpp10 and Tpp40, respectively) in the Trendelenburg position. There was no significant intergroup difference in change over time in the ONSD (p = 0.318). The ONSD increased significantly at Tpp40 when compared to Tind in both normocapnia and hypercapnia groups (p = 0.02 and 0.002, respectively). There was a significant intergroup difference in changes over time in the rSO2 (p < 0.001). The rSO2 decreased significantly in the normocapnia group (p = 0.01), whereas it increased significantly in the hypercapnia group at Tpp40 compared with Tind (p = 0.002). Alveolar dead space was significantly higher in the normocapnia group than in the hypercapnia group at Tpp40 (p = 0.001). In conclusion, mild hypercapnia during the LPV might not aggravate the increase in the ONSD during CO2 pneumoperitoneum in the Trendelenburg position and could improve rSO2 compared to normocapnia in patients undergoing gynecological laparoscopy with TIVA.

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

Background: Deliberate hypotension can reduce bleeding and improve visualization of the surgical field during functional endoscopic sinus surgery (FESS). However, hypotension may cause brain hypoperfusion and subsequent ischemic injuries, such as delayed awakening, stroke, postoperative delirium, and postoperative cognitive dysfunction. Near-infrared spectroscopy (NIRS) can be used to monitor real-time regional cerebral oxygen saturation (rSO2) levels to estimate brain perfusion. The present study aimed to evaluate the change in rSO2 induced by deliberate hypotension during FESS, and assess the impact of deliberate hypotension on the surgical process.Material and Methods: A randomized controlled trial was registered with the Chinese clinical trial registry (ChiCTR2000039846). A total of 40 patients were enrolled and randomly divided into the control and intervention groups, and finally, 39 patients were analyzed. Deliberate hypotension was induced in the intervention group using nicardipine and esmolol, whereas the control group received general anesthesia without deliberate hypotension. We recorded mean arterial pressure (MAP), saturation of pulse oximetry (SpO2), rSO2, and heart rate (HR) before induction of anesthesia (T0), immediately after induction of anesthesia (T1), at the beginning of the operation (corresponding with the establishment of deliberate hypotension) (T2), 10 min (T3) and 20 min (T4) after the operation began, at the end of the operation (corresponding with the end of deliberate hypotension) (T5), and 5 min (T6) and 15 min (T7) after the operation. The partial pressure of end-tidal carbon dioxide (PetCO2) was recorded at T1, T2, T3, T4, T5, and T6. The duration of surgery, intraoperative blood loss, tracheal extubation time, and the number of patients that experienced cerebral desaturation events (CDEs) were recorded. The surgical field was estimated postoperation based on the Fromme score.Results: A 30% decrease from the baseline MAP resulted in a decrease of intraoperative bleeding, improvement in the quality of the surgical field, and the shortening of the duration of surgery during FESS in the intervention group compared with the control group. In addition, rSO2 was reduced and no CDEs were experienced in the intervention group. Linear regression analysis demonstrated a correlation between the decline in rSO2 and that in MAP.Conclusions: A decrease in MAP to a certain level will cause a decrease of rSO2 in patients undergoing FESS under general anesthesia. Based on our findings, we recommend that the deliberate hypotensive target indicated by MAP be reduced by 30%, while PetCO2 is maintained at 35–40 mmHg and HR is maintained at about 60 beats per minute during FESS.

Decreases of regional cerebral oxygen saturation reading during hip arthroplasty associated with postoperative delirium in older adults

Background Postoperative delirium (POD) is a sign of deterioration in the homeostasis and physical status of the patient. However, there have been no reports regarding the relationship between the decrease of regional cerebral oxygen saturation (rSctO2) reading during surgery and the POD in hip replacement in the elder. This study aims to investigate this correlation and the incidence of POD.Methods We performed a retrospective study of 4834 patients who underwent hip arthroplasties between 2015 and 2019 at our hospital. Data were collected as part of routine patient care. The patients’ cognitive performance was evaluated by using the Manual of Mental Disorders (DSM-IV-TR 4th edition) criteria. Patients found to be delirious after surgery served as the delirium group, other patients who did not develop delirium after surgery regarded as the no-delirium group. The various factors including the decline of rSctO2 reading intraoperatively were assessed using Multivariable logistic regression models. Odds ratio (OR) and 95% confidence intervals (CI) are reported.Results POD was found in 27 patients (n=351); the incidence of POD was 7.7%; all of them were in their 70’s or 80’s. Lab data and rSctO2 reading before surgery were no significantly difference between the delirium group and the no-delirium group. Patients who displayed the decline of rSctO2 reading intraoperatively were at higher risk for POD (compared with no-delirium patients: OR2.169 CI 1.663-2.829 p=0.000) and gender (compared with no-delirium patients: OR 0.163 CI 0.029-0.909 p=0.039) was at a higher risk. Twenty-four patients recovered from POD gradually. One patient had persistent and severe cognitive dysfunction after surgery, two patients died of complications either acute pulmonary embolism 4 days after surgery or acute stroke 21 days after surgery respectively.Conclusions The incidence of POD was 7.7%. This study shows that the decline of rSctO2 reading during hip replacement surgery in the elder is associated with increased probability for the POD.

Effect of hemoglobin content on cerebral oxygen saturation during surgery for scoliosis in pediatric patients

Background Although regional cerebral oxygen saturation (rScO2) monitoring has been widely used in clinical practice, the relationship between hemoglobin (dHB) content and rScO2 is incompletely understood. The aim of this study was to analyze the effect of hemoglobin content on rScO2 in pediatric patients undergoing general anesthesia for correction of scoliosis. Methods Ninety-two pediatric patients aged 3 to 14 years undergoing scoliosis correction surgery were enrolled. Continuous monitoring of bilateral regional cerebral oxygen saturation by near-infrared spectroscopy (NIRS, CASMED, USA) was performed after entering the operation room. rScO2 was recorded when the patients entered the operating room (T0, baseline), after anesthesia induced intubation (T1), and after radial artery puncture (T2). The lowest value of rScO2 during surgery was also recorded. The arterial blood pressure (ABP), heart rate (HR), pulse oxygen saturation (SpO2), end tidal carbon dioxide partial pressure (PetCO2) were continuously recorded. Patients were classified as low rScO2 or high rScO2 group according to whether the lowest intraoperative rScO2 was 15% lower than the baseline value. An analysis and comparison of differences in hemoglobin content in these two groups was carried out. Results The preoperative hemoglobin-postoperative hemoglobin of patients in the high rScO2 group was significantly lower than that in the low rScO2 group (t = − 7.86, p < 0.01), the amount of bleeding during the operation was also less than that in the low rScO2 group (t = − 6.05, p < 0.01), and the systolic pressure of patients was higher than that in the low rScO2 group (t = 4.27, p < 0.01). Conclusions The decrease in hemoglobin level which occurs during surgery leads to a decrease in cerebral oxygen saturation. In order to ensure patient safety during surgery, it is necessary to carry out volume management and appropriate transfusion and fluid replacement in a timely manner. Trial registration Chinese Clinical Trial Registry, ChiCTR1800016359. Registered 28 May 2018.

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.