Intraoperative changes in blood pressure associated with cerebral desaturation in infants

Blood pressure and heart rates in neonates and preschool children: an analysis from 10 years of electronic recording

BACKGROUND

An acceptable systolic or mean arterial blood pressure for children 0-6 years during anesthesia is unknown. Accepted blood pressures reported in standard charts for healthy awake children may not apply to those undergoing anesthesia.

AIM

Our goal was to define observed blood pressures (BP) and heart rate (HR) in children 0-5 years during anesthesia.

METHODS

Data from the electronic health record database were available for a 10-year period from June 29, 2005 to July 22, 2015. A simple band-pass filter was applied to remove artifact in the physiologic time-series data for heart rate and blood pressure, with heart rate values 40 or above 250, mean or diastolic blood pressures below 20 or above 200, and systolic blood pressures below 30 or above 200 all excluded. For each anesthetic, the centiles of physiological variables (BP, HR) were calculated.

RESULTS

Data were available for 54 896 anesthetics in children 6 years and younger. There were 898 anesthesia reports available that included blood pressure measures immediately before induction. A larger number of anesthesia records (n = 30 008) were available for intraoperative blood pressure recording. The BP decrease after anesthesia induction was most pronounced in infants 0-10 weeks of age where there was a mean arterial blood pressure (MAP) decrease of 16.6-34.5% (mean 28.6%). Systolic blood pressure decreased by 16.3-32.6% (mean 25.5%). Values above a systolic blood pressure of 60 mm Hg were only noted in half the neonates during anesthesia. Heart rates, both before and after anesthesia induction, were similar.

CONCLUSION

Heart rate while under anesthesia appears a poor indicator for blood pressure changes. Recorded blood pressures in this current study, measured immediately before induction, were consistent with those in the literature. A mean MAP decrease of 28.6% was typical in those infants 0-10 weeks of age.

Assessment of risk factors for cerebral oxygen desaturation during neonatal and infant general anesthesia: an observational, prospective study

Background

Cerebral oxygen saturation (rSO₂c) decrease from baseline greater than 20 % during infant cardiac surgery was associated with postoperative neurologic changes and neurodevelopmental impairment at 1 year of age. So far, there is no sufficient evidence to support the routine monitoring of rSO₂c during general surgical procedures in children. We aimed to find out the frequency of cerebral desaturation 20 % or more from baseline and to identify possible predictors of change in cerebral oxygen saturation during neonatal and infant general surgery.

Methods

Forty-four infants up to 3 months of age were recruited. Before induction of anesthesia, two pediatric cerebral sensors were placed bilaterally to the forehead region and monitoring of regional cerebral saturation of oxygen was started and continued throughout the surgery. Simultaneously, mean arterial blood pressure (MAP), pulse oximetry (SpO₂), heart rate (HR), endtidal CO₂, expired fraction of sevoflurane and rectal temperature were recorded. The main outcome measure was rSO₂c value drop-off ≥20 % from baseline. Mann-Whitney U-test, chi-squared test, simple and multiple linear regression models were used for statistical analysis.

Results

Forty-three infants were analyzed. Drop-off ≥20 % in rSO₂c from baseline occurred in 8 (18.6 %) patients. There were no differences in basal rSO₂c, SpO₂, HR, endtidal CO₂, expired fraction of sevoflurane and rectal temperature between patients with and without desaturation 20 % or more from baseline. But the two groups differed with regard to gestation, preoperative mechanical ventilation and the use of vasoactive medications and red blood cell transfusions during surgery. Simple linear regression model showed, that gestation, age, preoperative mechanical ventilation and mean arterial pressure corresponding to minimal rSO₂c value during anesthesia (MAP_minrSO2c) were associated with a change in rSO₂c values. Multiple regression model including all above mentioned variables, revealed that only MAP_minrSO2c was predictive for a change in rSO₂c values (β (95 % confidence interval) -0.28 (−0.52–(−0.04)) p = 0.02).

Conclusions

Cerebral oxygen desaturation ≥20 % from baseline occurred in almost one fifth of patients. Although different perioperative factors can predispose to cerebral oxygenation changes, arterial blood pressure seems to be the most important. Gestation as another possible risk factor needs further investigation.

Trial registration

The international registration number NCT02423369. Retrospectively registered on April 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0274-2) contains supplementary material, which is available to authorized users.

Arterial blood pressure in anesthetized neonates and infants: a retrospective analysis of 1091 cases

BACKGROUND

Hypotension during general anesthesia in neonates and infants is considered to contribute to poor neurological outcome.

AIM

The aim of this retrospective analysis was to determine the incidence of hypotension after induction of anesthesia and sustained hypotension (>10 min) during the anesthesia, and to determine factors contributing to the development of (sustained) hypotension.

METHOD

We performed a retrospective analysis of 1091 electronic anesthesia records from children <1 year. Patients were stratified for age (group 1: <1 month, group 2: 1-3 months, group 3: 4-6 months, group 4: >6 months). Hypotension was defined as a mean arterial pressure (MAP) <35 mmHg in patients ≤6 months and <43 mmHg in patients >6 months.

RESULTS

The incidence of hypotension after induction was highest in group 1 (25.5%) [P = 0.009 vs group 2 (13.3%), P < 0.0001 vs groups 3 (3.4%) and 4 (1.0%)], in group 2, it was higher than in groups 3 and 4 (P < 0.0001), and in group 3, it was higher than in group 4 (P = 0.033). The incidence of sustained hypotension was highest in group 1 (43.6%) (P < 0.0001 vs groups 2-4), followed by group 2 (15.7%) [P < 0.0001 vs group 3 (3.4%) and P = 0.006 vs group 4 (8.8%)] and group 4 (P = 0.004 vs group 3). Hypotension after induction occurred more often in emergency procedures than in elective procedures in groups 1 (P = 0.002), 2 (P = 0.029), and 3 (P = 0.037).

CONCLUSION

Hypotension, both postinduction and sustained during surgery, is a common phenomenon in anesthetized children under 1 year, peaking in neonates. Generally accepted lower limits of MAP in anesthetized infants urgently need to be defined, enabling us to develop anesthesia strategies avoiding cerebral hypoperfusion.

Optimized preoperative fasting times decrease ketone body concentration and stabilize mean arterial blood pressure during induction of anesthesia in children younger than 36 months: a prospective observational cohort study

BACKGROUND

In pediatric anesthesia, preoperative fasting guidelines are still often exceeded.

OBJECTIVE

The objective of this noninterventional clinical observational cohort study was to evaluate the effect of an optimized preoperative fasting management (OPT) on glucose concentration, ketone bodies, acid-base balance, and change in mean arterial blood pressure (MAP) during induction of anesthesia in children.

METHODS

Children aged 0-36 months scheduled for elective surgery with OPT (n = 50) were compared with peers studied before optimizing preoperative fasting time (OLD) (n = 50) who were matched for weight, age, and height.

RESULTS

In children with OPT (n = 50), mean fasting time (6.0 ± 1.9 h vs 8.5 ± 3.5 h, P < 0.001), deviation from guideline (ΔGL) (1.2 ± 1.4 h vs 3.7 ± 3.1 h, P < 0.001, ΔGL>2 h 8% vs 70%), ketone bodies (0.2 ± 0.2 mmol·l(-1) vs 0.6 ± 0.6 mmol·l(-1) , P < 0.001), and incidence of hypotension (MAP <40 mmHg, 0 vs 5, P = 0.022) were statistically significantly lower and MAP after induction was statistically significantly higher (55.2 ± 9.5 mmHg vs 50.3 ± 9.8 mmHg, P = 0.015) as compared to children in the OLD (n = 50) group. Glucose, lactate, bicarbonate, base excess, and anion gap did not significantly differ.

CONCLUSION

Optimized fasting times improve the metabolic and hemodynamic condition during induction of anesthesia in children younger than 36 months of age.

Pediatric neuroanesthesia

PURPOSE OF REVIEW

A series of recent studies have changed the practice of pediatric neuroanesthesia, improving outcomes and making children's quality of life better.

RECENT FINDINGS

Potential long-term neurologic effects in infants and young children undergoing surgery and anesthesia have been recognized for over a decade. Several recent, well performed studies suggest that hypotension may also be a major contributor to postoperative neurologic impairment in children. Craniosynostosis surgery has also been the subject of extensive study, both related to decreasing blood loss and to optimizing postoperative outcomes.

SUMMARY

Although neurosurgical anesthesia research in the pediatric population can be ethically and logistically complex, resolving questions such as the optimal blood pressure during surgery and best management of infants undergoing repair of craniosynostosis will improve patient outcomes.

Perioperative use of cerebral and renal near-infrared spectroscopy in neonates: a 24-h observational study

BACKGROUND

Neonates undergoing surgery and intensive care still carry a significant morbidity and mortality often related to hypoxic/ischemic events; some of which may go undetected by conventional monitoring. Near-infrared spectroscopy (NIRS) is a noninvasive, continuous method of measuring regional tissue oxygen saturation, and may be used to supplement conventional monitoring to improve neonatal perioperative care. However, high costs and lack of evidence regarding improved outcomes have minimized wider perinatal use of NIRS. The aim of this study was to investigate the applicability of NIRS in neonates and premature infants undergoing noncardiac surgeries.

METHOD

Neonates were monitored with both cerebral and renal NIRS for 24 h after induction of anesthesia and compared with systemic blood pressure (BP), peripheral oxygen saturation (SpO2 ), and heart rate (HR).

RESULTS

A total of 23 368 min of data were collected from 21 neonates. NIRS reported cerebral/renal hypoxia 2.8 (±8.3)%/19.3 (±25.4)% of the time intraoperatively and 9.6 (±17.0)%/9.9 (±18.9)% of the time postoperatively. A moderate positive correlation was found between SpO2 and NIRS (φcerebral = 0.371, φrenal = 0.542). BP showed a weaker positive correlation (φcerebral = 0.231, φrenal = 0.246), and HR no correlation (φcerebral = -0.083, φrenal = -0.029). NIRS reported hypoxia two to three times more frequently than SpO2 , and SpO2 readings were 10-15 s delayed compared to NIRS. Furthermore, NIRS appeared effective at detecting postoperative apnea.

CONCLUSION

Near-infrared spectroscopy is an easily applicable technique that appears effective at detecting hypoxic events and postoperative apneas in neonates. The high incidences of regional hypoxia reported by NIRS in this study imply that there is a need for a more specific regional cerebral and renal monitoring. Despite some practical and economical limitations, NIRS may be considered a useful supplement to perinatal perioperative intensive care.

Noteworthy Literature in 2015

This article is a review of the literature published during the 12 months of 2015, which is of interest to the congenital cardiac anesthesiologist. While the review is not exhaustive, it identifies 7 themes in the literature for 2015 and cites 78 peer-reviewed publications.