[Cerebral near-infrared spectroscopy (NIRS) in paediatric anaesthesia]

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.

Monitoring Cerebral and Renal Oxygenation Status during Neonatal Digestive Surgeries Using Near Infrared Spectroscopy

BACKGROUND

Depending on the initial pathology, hypovolemia, intra-abdominal hypertension, and sepsis are often encountered in neonatal digestive surgery. Accurate newborn monitoring during and after surgery is essential to adapt resuscitation protocols. Near infrared spectroscopy (NIRS) is non-invasive and can detect hypoperfusion which indicates a low circulatory blood flow, regardless of the cause.

OBJECTIVE

Evaluating changes in cerebral and renal regional oxygen saturation during neonatal digestive surgeries, conducted according to normal practices, with commonly used monitoring parameters. Analyzing retrospectively the inter-relationships between NIRS values and mean arterial pressure (MAP) values as well as pre-ductal SpO₂.

METHODS

Prospective, descriptive, monocentric study. All neonates referred for surgery were included. NIRS allows the measurement of cerebral and renal oxygenation fluctuations, as well as calculating difference in intraoperative and postoperative values.

RESULTS

Nineteen patients were included. Cerebral regional oxygen saturation (C rSO₂) values were stable while renal regional oxygen saturation (R rSO₂) values tended to decrease with time during surgery. Indeed, 72% of rSO₂ decline episodes occurred after the first 30 min of surgery, without any significant statistical differences for the next 90 min of surgery. After surgery, the lowest average C and R rSO₂ values were evidenced during the first 6 h, with 60% of C rSO₂ and R rSO₂ anomalies occurring in that time frame. There was no significant statistical difference observed in the following 18 h. There was a significant correlation between R rSO₂ and SpO₂ values (p < 0.01), but not with C rSO₂ values. There was no correlation with the MAP either for the C rSO₂ values or R rSO₂ ones.

CONCLUSION

NIRS is a promising non-invasive bedside tool to monitor cerebral and tissue perfusion, analyzing tissue microcirculation. NIRS has its interest to guide neonatal digestive surgeries (bowel manipulation, viscera reduction) and may represent an early warning for identifying patients requiring resuscitation during or after these surgeries.

Intraoperative blood pressure and cerebral perfusion: strategies to clarify hemodynamic goals

Blood pressure can vary considerably during anesthesia. If blood pressure falls outside the limits of cerebrovascular autoregulation, children can become at risk of cerebral ischemic or hyperemic injury. However, the blood pressure limits of autoregulation are unclear in infants and children, and these limits can shift after brain injury. This article will review autoregulation, considerations for the hemodynamic management of children with brain injuries, and research on autoregulation monitoring techniques.