Sevoflurane anesthesia and brain perfusion

Assessment of Autoregulation of the Cerebral Circulation during Acute Lung Injury in a Neonatal Porcine Model

In neonates with acute lung injury (ALI), targeting lower oxygenation saturations is suggested to limit oxygen toxicity while maintaining vital organ function. Although thresholds for cerebral autoregulation are studied for the management of premature infants, the impact of hypoxia on hemodynamics, tissue oxygen consumption and extraction is not well understood in term infants with ALI. We examined hemodynamics, cerebral autoregulation and fractional oxygen extraction, as measured by near-infrared spectroscopy (NIRS) and blood gases, in a neonatal porcine oleic acid injury model of moderate ALI. We hypothesized that in ALI animals, cerebral oxygen extraction would be increased to a greater degree than kidney or gut oxygen extraction as indicative of the brain's adaptive efforts to increase cerebral oxygen extraction at the expense of splanchnic end organs. Fifteen anesthetized, ventilated 5-day-old neonatal piglets were divided into moderate lung injury by treatment with oleic acid or control (sham injection). The degree of lung injury was quantified at baseline and after establishment of ALI by blood gases, ventilation parameters and calculated oxygenation deficit, hemodynamic indices by echocardiography and lung injury score by ultrasound. PaCO2 was maintained constant during ventilation. Cerebral, renal and gut oxygenation was determined by NIRS during stepwise decreases in inspired oxygen from 50% to 21%, correlated with PaO2 and PvO2; changes in fractional oxygen extraction (ΔFOE) were calculated from NIRS and from regional blood gas samples. The proportion of cerebral autoregulation impairment attributable to blood pressure, and to hypoxemia, was calculated from autoregulation nomograms. ALI manifested as hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance and increased resistance, and marked increase in lung ultrasound score. Brain, gut and renal NIRS, obtained from probes placed over the anterior skull, central abdomen and flank, respectively, correlated with concurrent SVC (brain) or IVC (gut, renal) PvO2 and SvO2. Cerebral autoregulation was impaired after ALI as a function of blood pressure at all FiO2 steps, but predominantly by hypoxemia at FiO2 < 40%. Cerebral ΔFOE was higher in ALI animals at all FiO2 steps. We conclude that in an animal model of neonatal ALI, cerebrovascular blood flow regulation is primarily dependent on oxygenation. There is not a defined oxygenation threshold below which cerebral autoregulation is impaired in ALI. Cerebral oxygen extraction is enhanced in ALI, reflecting compensation for exhausted cerebral autoregulation due to the degree of hypoxemia and/or hypotension, thereby protecting against tissue hypoxia.

Continuous monitoring of cerebral blood flow during general anaesthesia in infants

Background

General anaesthesia is associated with neurocognitive deficits in infants after noncardiac surgery. Disturbances in cerebral perfusion as a result of systemic hypotension and impaired autoregulation may be a potential cause. Our aim was to study cerebral blood flow (CBF) velocity continuously during general anaesthesia in infants undergoing noncardiac surgery and compare variations in CBF velocity with simultaneously measured near-infrared spectroscopy (NIRS), blood pressure, and heart rate.

Methods

NeoDoppler, a recently developed ultrasound system, was used to monitor CBF velocity via the anterior fontanelle during induction and maintenance of general anaesthesia until the start of surgery, and during recovery. NIRS, blood pressure, and heart rate were monitored simultaneously and synchronised with the NeoDoppler measurements.

Results

Thirty infants, with a median postmenstrual age at surgery of 37.6 weeks (range 28.6-60.0) were included. Compared with baseline, the trend curves showed a decrease in CBF velocity during induction and maintenance of anaesthesia and returned to baseline values during recovery. End-diastolic velocity decreased in all infants during anaesthesia, on average by 59%, whereas peak systolic- and time-averaged velocities decreased by 26% and 45%, respectively. In comparison, the reduction in mean arterial pressure was only 20%. NIRS values were high and remained stable. When adjusting for mean arterial pressure, the significant decrease in end-diastolic velocity persisted, whereas there was only a small reduction in peak systolic velocity.

Conclusions

Continuous monitoring of CBF velocity using NeoDoppler during anaesthesia is feasible and may provide valuable information about cerebral perfusion contributing to a more targeted haemodynamic management in anaesthetised infants.

Effective dose of ephedrine for treatment of hypotension after induction of general anaesthesia in neonates and infants less than 6 months of age: a multicentre randomised, controlled, open label, dose escalation trial

BACKGROUND

The recommended dose of ephedrine in adults (0.1 mg kg^-1) frequently fails to treat hypotension after induction of general anaesthesia in neonates and infants less than 6 months of age. The aim of this study was to determine the optimal dose of ephedrine in this population for the treatment of hypotension after induction of general anaesthesia with sevoflurane.

METHODS

We conducted a multicentre, prospective, randomised, open-label, controlled, dose-escalation trial. Subjects were randomised if presenting a >20% change from baseline in MAP. Six cohorts of 20 subjects each were enrolled. Ten subjects in the first cohort received 0.1 mg kg^-1 i. v. (reference dose). For each subsequent cohort, 10 subjects were assigned to the next higher dose (consecutively 0.6, 0.8, 1, 1.2, and 1.4 mg kg^-1 i. v.), and the other subjects were assigned to one or more doses already investigated in previous cohorts. The primary outcome was the return of MAP to >80% of baseline at least once within 10 min after ephedrine administration.

RESULTS

A total of 119 infants (25% females), with a mean age (standard deviation) of 2.7 (1.3) months, received their allocated dose of ephedrine. The optimal dose of ephedrine was 1.2 mg kg^-1, with a percentage of success of 65.5% (95% confidence interval, 35.6-86.4). The doses of ephedrine investigated did not induce adverse events.

CONCLUSIONS

Doses of ephedrine much higher (∼10-fold) than those used in adults are necessary in neonates and infants for the treatment of hypotension after induction of general anaesthesia with sevoflurane.

CLINICAL TRIAL REGISTRATION

NCT02384876.

Intraoperative monitoring of cerebrovascular autoregulation in infants and toddlers receiving major elective surgery to determine the individually optimal blood pressure - a pilot study

INTRODUCTION

Inducing general anesthesia (GA) in children can considerably affect blood pressure, and the rate of severe critical events owing to this remains high. Cerebrovascular autoregulation (CAR) protects the brain against blood-flow-related injury. Impaired CAR may contribute to the risk of cerebral hypoxic-ischemic or hyperemic injury. However, blood pressure limits of autoregulation (LAR) in infants and children are unclear.

MATERIALS AND METHODS

In this pilot study CAR was monitored prospectively in 20 patients aged <4 years receiving elective surgery under GA. Cardiac- or neurosurgical procedures were excluded. The possibility of calculating the CAR index hemoglobin volume index (HVx), by correlating near-infrared-spectroscopy (NIRS)-derived relative cerebral tissue hemoglobin and invasive mean arterial blood pressure (MAP) was determined. Optimal MAP (MAPopt), LAR, and the proportion of time with a MAP outside LAR were determined.

RESULTS

The mean patient age was 14 ± 10 months. MAPopt could be determined in 19 of 20 patients, with an average of 62 ± 12 mmHg. The required time for a first MAPopt depended on the extent of spontaneous MAP fluctuations. The actual MAP was outside the LAR in 30% ± 24% of the measuring time. MAPopt significantly differed among patients with similar demographics. The CAR range averaged 19 ± 6 mmHg. Using weight-adjusted blood pressure recommendations or regional cerebral tissue saturation, only a fraction of the phases with inadequate MAP could be identified.

CONCLUSION

Non-invasive CAR monitoring using NIRS-derived HVx in infants, toddlers, and children receiving elective surgery under GA was reliable and provided robust data in this pilot study. Using a CAR-driven approach, individual MAPopt could be determined intraoperatively. The intensity of blood pressure fluctuations influences the initial measuring time. MAPopt may differ considerably from recommendations in the literature, and the MAP range within LAR in children may be smaller than that in adults. The necessity of manual artifact elimination represents a limitation. Larger prospective and multicenter cohort studies are necessary to confirm the feasibility of CAR-driven MAP management in children receiving major surgery under GA and to enable an interventional trial design using MAPopt as a target.

Comparison of cerebral oxygen desaturation events between children under general anesthesia and chloral hydrate sedation - a randomized controlled trial

BACKGROUND

During pediatric general anesthesia (GA) and sedation, clinicians aim to maintain physiological parameters within normal ranges. Accordingly, regional cerebral oxygen saturation (rScO₂) should not drop below preintervention baselines. Our study compared rScO₂ desaturation events in children undergoing GA or chloral hydrate sedation (CHS).

METHODS

Ninety-two children undergoing long auditory assessments were randomly assigned to two study arms: CHS (n = 40) and GA (n = 52). Data of 81 children (mean age 13.8 months, range 1-36 months) were analyzed. In the GA group, we followed a predefined 10 N concept (no fear, no pain, normovolemia, normotension, normocardia, normoxemia, normocapnia, normonatremia, normoglycemia, and normothermia). In this group, ENT surgeons performed minor interventions in 29 patients based on intraprocedural microscopic ear examinations. In the CHS group, recommendations for monitoring and treatment of children undergoing moderate sedation were met. Furthermore, children received a double-barreled nasal oxygen cannula to measure end-tidal carbon dioxide (etCO₂) and allow oxygen administration. Chloral hydrate was administered in the parent's presence. Children had no intravenous access which is an advantage of sedation techniques. In both groups, recommendations for fasting were followed and an experienced anesthesiologist was present during the entire procedure. Adverse event (AE) was a decline in cerebral oxygenation to below 50% or below 20% from the baseline for ≥1 min. The primary endpoint was the number of children with AE across the study arms. Secondary variables were: fraction of inspired oxygen (F_IO₂), oxygen saturation (S_pO₂), etCO₂, systolic and mean blood pressure (BP), and heart rate (HR); these variables were analyzed for their association with drop in rScO₂ to below baseline (%drop_rScO₂).

RESULTS

The incidence of AE across groups was not different. The analysis of secondary endpoints showed evidence that %drop_rScO₂ is more dependent on HR and F_IO₂ than on BP and etCO₂.

CONCLUSIONS

This study highlights the strong association between HR and rScO2 in children aged < 3 years, whereas previous studies had primarily discussed the role of BP and etCO₂. Prompt HR correction may result in shorter periods of cerebral desaturation.

TRIAL REGISTRATION

The study was retrospectively registered with the German Clinical Trials Registry (DRKS00024362, 04/02/2021).

[Perioperative Complications in Pediatric Anesthesia]

Perioperative complications are more frequent in younger children, especially under the age of 3 years and in infants. The anatomy and physiology of children cause more respiratory adverse events compared to adult patients. Respiratory adverse events account for 60% of all anesthetic complications. Main risk factors for respiratory adverse events are upper respiratory tract infections. Keeping the airway management as noninvasive as possible helps prevent major complications.Perioperative hypotension can compromise cerebral oxygenation, especially when hypocapnia and anemia are present. Congenital heart disease leads to a higher cardiovascular adverse event rate and should be diagnosed preoperatively whenever possible.Venous and arterial cannulation is more challenging in children and complications are more frequent even for experienced practitioners. Ultrasound is an essential tool for peripheral venous access as well as for central venous catheterization.Medication errors are more common in pediatric than in adult patients. Charts and electronic calculation of dosing can increase safety of prescriptions. Standardized storage of medications at all workplaces, avoiding look-alike medications in the same compartment and storing high-risk medications separately help prevent substitution errors.Emergence delirium and postoperative nausea and vomiting (PONV) are the most frequent postoperative adverse events. For diagnosing emergence delirium, the PAED scale is a helpful tool. Prevention of emergence delirium by pharmacological and general measures plays a key role for patient outcome. Routine prophylaxis of PONV above the age of 3 years is recommended.Frequency and severity of perioperative adverse events in pediatric anesthesia can be reduced by using algorithms and defined processes to allow for structured actions. Efficient communication and organization are mainstays for utilizing all medical options to reduce the risk of complications.

Blood pressure and flow in pediatric anesthesia: An educational review

During recent years, a lot of interest has been focused on blood pressure in the context of pediatric anesthesia, trying to define what is normal in relation to age and what numeric values that should be regarded as hypotension, needing active intervention. However, blood pressure is mainly measured as a proxy for flow, that is, cardiac output. Thus, just focusing on specific blood pressure numbers may not necessarily be very useful or appropriate. The aim of this educational review is to put the issue of intraoperative blood pressure in the context of pediatric anesthesia in further perspective.

General versus general anaesthesia combined with caudal block in laparoscopic-assisted Soave pull-through of Hirschsprung disease: a retrospective study

BACKGROUND

Caudal block is one of the most preferred regional anesthesia for sub-umbilical region surgeries in the pediatric population. However, few studies are available on caudal block performed in laparoscopic-assisted Soave pull-through of Hirschsprung disease (HD). We aimed to compare general anesthesia (GA) and general anesthesia combined with caudal block (GA + CA) in laparoscopic-assisted Soave pull-through of HD.

METHODS

A retrospective review was performed in children with HD operated in our hospital between 2017 and 2020. Patients were divided into the GA and GA + CA group. The primary outcome was the duration of operation, and secondary outcomes included intraoperative hemodynamic changes, the Face, Legs, Activity, Cry, Consolability (FLACC) scale, dose of anesthetics, and incidence of side effects.

RESULTS

A total of 47 children with HD were included in the study, including 20 in the GA group and 27 in the GA + CA Group. The two groups were similar in age, gender, weight and type of HD (P > 0.05). The GA + CA group had significantly shorter duration of operation (especially the transanal operation time) (median 1.20 h vs. 0.83 h, P < 0.01) and recovery time (mean 18.05 min vs. 11.89 min, P < 0.01). The mean doses of sufentanil and rocuronium bromide during the procedure and FLACC scores at 1 h and 6 h after surgery were also lower in the GA + CA group (p < 0.01). The hemodynamic changes in the GA + CA group were more stable at time of t2 (during transanal operation) and t3 (10 min after transanal operation), but there was no significant difference in the incidence of postoperative side effects between the two groups (P = 1.000).

CONCLUSION

General anesthesia combined with caudal block can shorten the duration of operation, and provide more stable intraoperative hemodynamics and better postoperative analgesia.

Spinal Anesthesia is Superior to General Anesthesia for Percutaneous Achilles Tenotomy in Infants

BACKGROUND

Concern about the effects of inhaled, halogenated anesthetics on neurodevelopment of infants has renewed interest in regional anesthesia as an alternative to general anesthesia (GA). Infants undergoing percutaneous Achilles tenotomy (PAT) are well suited for spinal anesthesia (SP).

METHODS

Thirty infants (mean age: 2.3 mo) undergoing PAT with SP were compared with 15 infants (mean age: 2.0 mo) undergoing PAT with GA. Data collected included perioperative times, heart rate and blood pressure, and the administration of opioids.

RESULTS

Ten of 15 GA (67%) patients received perioperative opioids as opposed to 1 of 30 SP patients (3.3%) (P<0.0001). The time from the start of anesthesia to the start of surgery was shorter in the SP group (8.5 vs. 14 min, P<0.0009). The time from the start of anesthesia to first oral intake was shorter in the SP group (12 vs. 31 min, P<0.0033). The time of first phase recovery (phase 1 post anesthesia care unit) was shorter in the SP group (15.5 vs. 34 min, P<0.0026). Surgery time was not significantly different between the groups (SP: 15.5 min, GA: 15 min, P=0.81).

CONCLUSION

Infants undergoing PAT with SP received less opioid, did not require an airway device, did not receive potent inhaled, halogenated hydrocarbon anesthetics, and exhibited faster and qualitatively better postoperative recovery.

LEVEL OF EVIDENCE

Level III-case control study.

Systemic and regional cerebral perfusion in small infants undergoing minor lower abdominal surgery under awake caudal anaesthesia: An observational study

BACKGROUND

Infants undergoing general anaesthesia have an increased risk of severe respiratory and cardiovascular critical events. Awake caudal anaesthesia is an alternative for small infants undergoing minor lower abdominal surgery. While clinical experience has shown stable intra-operative haemodynamic conditions, there are no studies evaluating systemic and regional cerebral perfusion during such a procedure.

OBJECTIVES

The purpose of this study was to evaluate the effects of awake caudal anaesthesia on systemic and regional cerebral perfusion in small infants.

DESIGN

A prospective observational cohort study.

SETTING

Clinic of Anaesthesiology, University Children's Hospital, between November 2017 and June 2018.

PATIENTS

Twenty small infants (postmenstrual age 36 to 54 weeks, weight 1800 to 5700 g) scheduled for lower abdominal surgery under awake caudal anaesthesia were enrolled in this study.

INTERVENTION

Standard monitoring was expanded to include cardiac index using electrical velocimetry and regional cerebral oxygen saturation using near infrared spectroscopy. The caudal block was performed with 0.3% ropivacaine 1 ml kg Hypotension was defined as mean arterial blood pressure (BP) less than 35 mmHg and regional cerebral desaturation as regional cerebral oxygen saturation less than 80% of baseline.

MAIN OUTCOMES

Mean arterial BP, cardiac index and regional cerebral oxygen saturation parameters under awake caudal anaesthesia.

RESULTS

Mean arterial BP, cardiac index and regional cerebral oxygen saturation remained above the predefined lower limits. No episodes of hypotension or regional cerebral desaturation were observed. Operation time was 35 ± 13 (range 20 to 71) min. The infants were discharged to the neonatal ward after the end of surgery, and milk was fed 22 ± 15 (range 6 to 55) min thereafter. Five preterm infants experienced self-limiting episodes of apnoea intra-operatively.

CONCLUSION

The current study shows that awake caudal anaesthesia does not impair systemic and regional cerebral perfusion in small infants.

TRIAL REGISTRATION

German registry of clinical studies (DRKS-ID: 800015742).

The utility of arterial spin labeling in the presurgical evaluation of poorly defined focal epilepsy in children

OBJECTIVE

The authors sought to assess the utility of arterial spin labeling (ASL) perfusion 3T-MRI for the presurgical evaluation of poorly defined focal epilepsy in pediatric patients.

METHODS

Pseudocontinuous ASL perfusion 3T-MRI was performed in 25 consecutive children with poorly defined focal epilepsy. ASL perfusion abnormalities were detected qualitatively by visual inspection and quantitatively by calculating asymmetry index (AI) maps and significant z-score cluster maps based on successfully operated cases. ASL results were prospectively compared to scalp EEG, structural 3T-MRI, FDG-PET, ictal/interictal SPECT, magnetoencephalography (MEG), and intracranial recording results, as well as the final surgically proven epileptogenic zone (EZ) in operated patients who had at least 1 year of good (Engel class I/II) seizure outcome and positive histopathology results.

RESULTS

Qualitative ASL perfusion abnormalities were found in 17/25 cases (68%), specifically in 17/20 MRI-positive cases (85.0%) and in none of the 5 MRI-negative cases. ASL was concordant with localizing scalp EEG findings in 66.7%, structural 3T-MRI in 90%, FDG-PET in 75%, ictal/interictal SPECT in 62.5%, and MEG in 75% of cases, and with intracranial recording results in 40% of cases. Eleven patients underwent surgery; in all 11 cases the EZ was surgically proven by positive histopathology results and the patient having at least 1 year of good seizure outcome. ASL results were concordant with this final surgically proven EZ in 10/11 cases (sensitivity 91%, specificity 50%). All 10 ASL-positive patients who underwent surgery had positive surgical pathology results and good long-term postsurgical seizure outcome at a mean follow-up of 39 months. Retrospective quantitative analysis based on significant z-score clusters found 1 true-positive result that was missed by qualitative analysis and 3 additional false-positive results (sensitivity 100%, specificity 23%).

CONCLUSIONS

ASL supports the hypothesis regarding the EZ in poorly defined focal epilepsy cases in children. Due to its convenience and noninvasive nature, the authors recommend that ASL be added routinely to the presurgical MRI evaluation of epilepsy. Future optimized quantitative methods may improve the diagnostic yield of this technique.

Potential Relationship between Cerebral Fractional Tissue Oxygen Extraction (FTOE) and the Use of Sedative Agents during the Perioperative Period in Neonates and Infants

Fractional tissue oxygen extraction (FTOE) by means of cerebral near-infrared spectroscopy (NIRS) provides information about oxygen uptake in the brain. Experimental animal data suggest that sedative agents decrease cerebral oxygen demand. The aim of the present study was to investigate the association between the cerebral FTOE and the use of pre and intraoperative sedative agents in infants aged 1-90 days. Cerebral NIRS was continuously applied during open major non-cardiac surgery in 46 infants. The main outcomes were the mean intraoperative FTOE and the percentage (%) of time of intraoperative hyperoxia_FTOE relative to the total duration of anesthesia. Hyperoxia_FTOE was defined as FTOE ≤ 0.1. Cumulative doses of sedative agents (benzodiazepines and morphine), given up to 24 h preoperatively, correlated with the mean intraoperative FTOE (Spearman's rho = -0.298, p = 0.0440) and were predictive for the % of time of intraoperative hyperoxia_FTOE (β (95% CI) 47.12 (7.32; 86.92)) when adjusted for the patients' age, type of surgery, preoperative hemoglobin, intraoperative sevoflurane and fentanyl dose, mean intraoperative arterial blood pressure, and end-tidal CO₂ by multivariate 0.75 quantile regression. There was no association with 0.5 quantile regression. We observed the suggestive positive association of decreased fractional cerebral tissue oxygen extraction and the use of sedative agents in neonates and infants undergoing surgery.

[Near-infrared spectroscopy : Technique, development, current use and perspectives]

Near-infrared spectroscopy (NIRS) has been available in research and clinical practice for more than four decades. Recently, there have been numerous publications and substantial developments in the field. This article describes the clinical application of NIRS in relation to current guidelines, with a focus on pediatric and cardiac anesthesia. It discusses technical and physiological principles, pitfalls in clinical use and presents (patho)physiological influencing factors and derived variables, such as fractional oxygen extraction (FOE) and the cerebral oxygen index (COx). Recommendations for the interpretation of NIRS values in connection with influencing factors, such as oxygen transport capacity, gas exchange and circulation as well as an algorithm for cardiac anesthesia are presented. Limitations of the method and the lack of comparability of values from different devices as well as generally accepted standard values are explained. Technical differences and advantages compared to pulse oxymetry and transcranial Doppler sonography are illuminated. Finally, the prognostic significance and requirements for future clinical studies are discussed.

Effect of etomidate on systemic and regional cerebral perfusion in neonates and infants with congenital heart disease: A prospective observational study

BACKGROUND

Neonates and infants with congenital heart disease undergoing general anesthesia have an increased risk for critical cardiovascular events. Etomidate produces very minimal changes in hemodynamic parameters in older children with congenital heart disease. There is a lack of studies evaluating the effect of etomidate on systemic and regional cerebral perfusion in neonates and infants with congenital heart disease.

AIM

The aim of this prospective observational study was to evaluate the effect of etomidate on systemic and regional cerebral perfusion in neonates and infants with congenital heart disease.

METHODS

In fifty infants aged 0-11 months (24% neonates n = 12) with congenital heart disease, mean arterial blood pressure, cardiac index using electrical cardiometry, and regional cerebral oxygen saturation using near-infrared spectroscopy were measured at baseline and 1, 3, 5, and 10 minutes after induction by 0.4 mg kg^-1 etomidate. Hypotension was defined as a mean arterial blood pressure under 35 mm Hg and cerebral desaturation as a regional cerebral oxygen saturation of less than 80% of baseline.

RESULTS

Mean arterial blood pressure, cardiac index, and regional cerebral oxygen saturation remained stable above the predefined limits. Mean arterial blood pressure decreased slightly within a physiological range after 3 minutes (P = .005, 95% CI:-5.9 to -1.0). No significant change in cardiac index could be observed.

CONCLUSION

Etomidate 0.4mg kg^-1 does not impair systemic or regional cerebral perfusion in neonates or infants with congenital heart disease.

Effects of awake caudal anesthesia on mean arterial blood pressure in very low birthweight infants

Background

Intraoperative blood pressure is a relevant variable for postoperative outcome in infants undergoing surgical procedures. It is therefore important to know whether the type of anesthesia has an impact on intraoperative blood pressure management in very low birth weight infants. Here, we retrospectively analyzed intraoperative blood pressure in very low birthweight infants receiving either awake caudal anesthesia without sedation, or caudal block in combination with general anesthesia, both for open inguinal hernia repair.

Methods

Ethical approval was provided by the University of Tuebingen Ethical Committee on 05/29/2018 with the project number 403/2018BO2. Patient records of infants admitted by the neonatologist (median age at birth 31.1 ± 3.5 weeks, median weight at birth 1240 ± 521 g) which were scheduled for inguinal hernia repair were retrospectively evaluated for the course of mean arterial blood pressure and perioperative interventions to stabilize blood pressure. A total of 42 patients were included, 16 patients (11 boys, 5 girls) received awake caudal anesthesia, 26 patients (22 boys, 4 girls) a combination of general anesthesia and caudal block.

Results

Approximately 3% of the measured mean arterial blood pressure values in the caudal anesthesia group were below a critical margin of 35 mmHg, in contrast to 47% in the combined anesthesia group (p < 0.001). Patients in the latter group showed a significantly larger drop of mean arterial blood pressure below 35 mmHg (4.7 ± 2.7 mmHg vs. 1.9 ± 1.6 mmHg; p < 0.005) and a significantly longer time of mean arterial blood pressure below 35 mmHg (25.6 ± 26.0 min vs. 0.9 ± 2.3 min; p < 0.001), although they received more volume and vasopressor boluses for stabilization (27 ± 14.8 ml vs. 10 ± 4.1 ml; p < 0.01 and 0.15 ± 0.06 ml vs. 0 ml of cafedrine/theoadrenaline; p < 0.001).

Conclusions

The study indicates that the use of caudal block as stand alone procedure for inguinal hernia repair in very low birthweight infants might be advantageous in preventing critical blood pressure drops compared to a combination of caudal block with general anesthesia.

Is Anesthesia Bad for the Brain? Current Knowledge on the Impact of Anesthetics on the Developing Brain

There are compelling preclinical data that common general anesthetics cause increased neuroapoptosis in juvenile animals. Retrospective studies demonstrate that young children exposed to anesthesia have school difficulties, which could be caused by anesthetic neurotoxicity, perioperative hemodynamic and homeostatic instability, underlying morbidity, or the neuroinflammatory effects of surgical trauma. Unnecessary procedures should be avoided. Baseline measures of blood pressure are important in determining perioperative blood pressure goals. Inadvertent hypocapnia or moderate hypercapnia and hyperoxia or hypoxia should be avoided. Pediatric patients should be maintained in a normothermic, euglycemic state with neutral positioning. Improving outcomes of infants and children requires the collaboration of anesthesiologists, surgeons, pediatricians and neonatologists.

General Anesthesia Maintained with Sevoflurane versus Propofol in Pediatric Surgery Shorter Than 1 Hour: A Randomized Single-Blind Study

Background

Sevoflurane was compared with propofol for general anesthesia maintenance in pediatric operations lasting less than 1 hour in terms of anesthetic effect and postoperative recovery.

Material/Methods

Children scheduled for inguinal hernia repair or hydrocele testis repair were randomly assigned to receive general anesthesia maintained with either sevoflurane (n=43) or propofol (n=43). The ilioinguinal nerve was blocked with 1% lidocaine (7 mg/kg) after intravenous administration of ketamine (2 mg/kg). At the end of the surgery in patients receiving sevoflurane, sevoflurane was stopped and a bolus of propofol of 1 mg/kg was administered.

Results

Sevoflurane was associated with significantly less use of ketamine (35.1±10.6 mg) than was propofol (59.0±28.0 mg; P<0.001). In addition, sevoflurane was associated with a significantly shorter time in the post-anesthesia care unit (52.1±9.0 min) than was propofol (68.8±15.3 min; P<0.001). Propofol was associated with a significantly higher incidence of intraoperative body movement (33.3%) than was sevoflurane (13.5%; P=0.045). However, the 2 groups showed no important differences in other adverse events such as hypoxia, emergence agitation, and additional use of propofol.

Conclusions

In pediatric surgery lasting less than 1 hour, anesthesia maintained with sevoflurane was associated with significantly less use of ketamine, shorter postoperative recovery time, and less intraoperative body movement than was propofol.

Effects of spinal anesthesia and sedation with dexmedetomidine or propofol on cerebral regional oxygen saturation and systemic oxygenation a period after spinal injection

PURPOSE

To evaluate changes in cerebral regional oxygen saturation (rSO₂) after spinal anesthesia and compare the changes in rSO₂ and systemic oxygenation between dexmedetomidine sedation and propofol sedation.

METHODS

Thirty-six patients scheduled to undergo transurethral surgery under spinal anesthesia were randomly assigned to the dexmedetomidine (n = 18) and propofol groups (n = 18). We used near-infrared spectroscopy sensors to measure rSO₂, and obtained data from each side were averaged. After oxygen insufflation, baseline measurements of mean arterial blood pressure (MAP), heart rate, rSO₂, pulse oximetry saturation (SpO₂), bispectral index, and body temperature were made. After spinal anesthesia, we measured these parameters every 5 min. Twenty minutes after spinal injection, dexmedetomidine or propofol administration was started. We measured each parameter at 10, 25, and 40 min after the administration of dexmedetomidine or propofol.

RESULTS

The baseline rSO₂ in the dexmedetomidine group was 71.3 ± 7.3%, and that in the propofol group was 71.8 ± 5.6%. After spinal anesthesia, rSO₂ in both groups decreased significantly (dexmedetomidine group: 65.4 ± 6.9%; propofol group: 64.3 ± 7.4%). After administering sedatives, rSO₂ was equivalent after spinal anesthesia. rSO₂ was comparable between the two groups. MAP and SpO₂ were significantly higher in the dexmedetomidine group than in the propofol group.

CONCLUSION

Spinal anesthesia decreased rSO₂; however, the decline was not severe. Dexmedetomidine and propofol did not compromise cerebral oxygenation under spinal anesthesia. Nevertheless, MAP and SpO₂ were more stable in dexmedetomidine sedation than in propofol sedation. Dexmedetomidine may be suitable for spinal anesthesia.

Beyond Anesthesia Toxicity: Anesthetic Considerations to Lessen the Risk of Neonatal Neurological Injury

Infants who undergo surgical procedures in the first few months of life are at a higher risk of death or subsequent neurodevelopmental abnormalities. Although the pathogenesis of these outcomes is multifactorial, an understanding of the nature and pathogenesis of brain injury in these infants may assist the anesthesiologist in consideration of their day-to-day practice to minimize such risks. This review will summarize the main types of brain injury in preterm and term infants and their key pathways. In addition, the review will address key potential pathogenic pathways that may be modifiable including intraoperative hypotension, hypocapnia, hyperoxia or hypoxia, hypoglycemia, and hyperthermia. Each of these conditions may increase the risk of perioperative neurological injury, but their long-term ramifications are unclear.

Sevoflurane Inhibits Proliferation and Invasion of Human Ovarian Cancer Cells by Regulating JNK and p38 MAPK Signaling Pathway

Aim

Sevoflurane is a halogen inhaled anesthetic, and we aimed to probe the effect of sevoflurane on proliferation and invasion of human ovarian cancer (OC) and its mechanism.

Methods

OC cell lines were divided into 4 groups including control, sevoflurane low concentration (1.7%), medium concentration (3.4%) and high concentration (5.1%) groups. Flow cytometry and MTT assay were, respectively, employed to detect the cell apoptosis and proliferation. Transwell assay was applied to measure the cell migration and invasion viability. The gene and protein expressions were assessed using qRT-PCR and Western blot. The expressions of MAPK signaling pathway-related proteins were evaluated by Western blot. The p38 and JNK inhibitors were, respectively, added into the high concentration group to analyze the relationship between sevoflurane and modulatingmitogen-activated protein kinase (MAPK) pathway in OC. Nude mice models were constructed to explore the effect of sevoflurane on OC tumor growth in vivo.

Results

Sevoflurane inhibited OC proliferation in vitro and in vivo. It could also promote OC cell apoptosis in a dose-dependent manner. Sevoflurane suppressed the OC cell migration and invasion, and these effects were positively correlated with the dose of sevoflurane. Moreover, sevoflurane treatment inhibited the expressions of PCNA, Twist, cleaved-caspase-3/caspase-3, MMP-2 and MMP-9. In addition, sevoflurane repressed the phosphorylation of JNK and p38 MAPK. When the MAPK pathway was interdicted, the cell proliferation, apoptosis, migration and invasion activity were recovered after sevoflurane treatment.

Conclusion

Sevoflurane affected cell biological activities in OC by regulating JNK and p38 MAPK signaling pathway.

A practical approach to cerebral near-infrared spectroscopy (NIRS) directed hemodynamic management in noncardiac pediatric anesthesia

Safeguarding cerebral function is of major importance during pediatric anesthesia. Premature, ex-premature, and full-term neonates can be vulnerable to physiological changes that occur during anesthesia and surgery. Data from studies performed during pediatric cardiac surgery and in neonatal/pediatric intensive care units have shown the benefits of near-infrared spectroscopy (NIRS) monitoring of regional cerebral oxygenation (c-rSO₂ ). However, NIRS monitoring is seldom used during noncardiac pediatric anesthesia. Despite compelling evidence that blood pressure does not reflect end-organ perfusion, it is still regarded as the most important determinant of cerebral perfusion and the most relevant hemodynamic management target parameter by most (pediatric) anesthetists. The principle of NIRS monitoring is not self-explanatory and sometimes seems even counterintuitive, which may explain why many anesthesiologists are reserved regarding its use. The first part of this paper is dedicated to a clinical introduction to NIRS monitoring. Despite scientific efforts, it has not yet been possible to define individual lower limit c-rSO₂ values and it is unlikely this will succeed in the near future. Nonetheless, published treatment algorithms usually specify c-rSO₂ values which may be associated with cerebral hypoxia. Our treatment guideline for maintaining sufficient cerebral oxygenation differs fundamentally from all previously published approaches. We define a baseline c-rSO₂ value, registered in the awake child prior to anesthesia induction, as the lowest acceptable limit during anesthesia and surgery. The cerebral rSO₂ is the single target parameter, while blood pressure, heart rate, P_a CO₂ , and SaO₂ are major parameters that determine the c-rSO2. Cerebral NIRS monitoring, interpreted together with its continuously available contributing parameters, may help avoid potentially harmful episodes of cerebral desaturation in anesthetized pediatric patients.

Effects of moderate and severe arterial hypotension on intracerebral perfusion and brain tissue oxygenation in piglets

BACKGROUND

Hypotension is common in anaesthetised children, and its impact on cerebral oxygenation is unknown. The goal of the present study was to investigate the effects of moderate systemic arterial hypotension (mHT) and severe hypotension (sHT) on cerebral perfusion and brain tissue oxygenation in piglets.

METHODS

Twenty-seven anaesthetised piglets were randomly allocated to a control group, mHT group, or sHT group. Cerebral monitoring comprised a tissue oxygen partial pressure ( [Formula: see text] ) and laser Doppler (LD) perfusion probe advanced into the brain tissue, and a near-infrared spectroscopy sensor placed over the skin measuring regional oxygen saturation (rSO₂). Arterial hypotension was induced by blood withdrawal and i.v. nitroprusside infusion [target MAP: 35-38 (mHT) and 27-30 (sHT) mm Hg]. Data were analysed at baseline, and every 20 min during and after treatment.

RESULTS

Compared with control, [Formula: see text] decreased equally with mHT and sHT [mean (SD) after 60 min: control: 17.1 (6.4); mHT: 6.4 (3.6); sHT: 7.2 (4.3) mm Hg]. No differences between groups were detected for rSO₂ and LD during treatment. However, in the sHT group, rSO₂ increased after restoring normotension [from 49.3 (9.5) to 58.9 (8.9)% Post60]. sHT was associated with an increase in blood lactate [from 1.5 (0.4) to 2.4 (0.9) mmol L^-1], and a decrease in bicarbonate [28 (2.4) to 25.8 (2.6) mmol L^-1] and base excess [4.7 (1.9) to 2.0 (2.7) mmol L^-1] between baseline and 60 min after the start of the experiment.

CONCLUSIONS

Induction of mHT and sHT by hypovolaemia and nitroprusside infusion caused alterations in brain tissue oxygenation in a piglet model, but without detectable changes in brain tissue perfusion and regional oxygen saturation.

Choosing Wisely in pediatric anesthesia: An interpretation from the German Scientific Working Group of Paediatric Anaesthesia (WAKKA)

Inspired by the Choosing Wisely initiative, a group of pediatric anesthesiologists representing the German Working Group on Paediatric Anaesthesia (WAKKA) coined and agreed upon 10 concise positive ("dos") or negative ("don'ts") evidence-based recommendations. (i) In infants and children with robust indications for surgical, interventional, or diagnostic procedures, anesthesia or sedation should not be avoided or delayed due to the potential neurotoxicity associated with the exposure to anesthetics. (ii) In children without relevant preexisting illnesses (ie, ASA status I/II) who are scheduled for elective minor or medium-risk surgical procedures, no routine blood tests should be performed. (iii) Parental presence during the induction of anesthesia should be an option for children whenever possible. (iv) Perioperative fasting should be safe and child-friendly with shorter real fasting times and more liberal postoperative drinking and enteral feeding. (v) Perioperative fluid therapy should be safe and effective with physiologically composed balanced electrolyte solutions to maintain a normal extracellular fluid volume; addition of 1%-2.5% glucose to avoid lipolysis, hypoglycemia, and hyperglycemia, and colloids as needed to maintain a normal blood volume. (vi) To achieve safe and successful airway management, the locally accepted airway algorithm and continued teaching and training of basic and alternative techniques of ventilation and endotracheal intubation are required. (vii) Ultrasound and imaging systems (eg, transillumination) should be available for achieving central venous access and challenging peripheral venous and arterial access. (viii) Perioperative disturbances of the patient's homeostasis, such as hypotension, hypocapnia, hypothermia, hypoglycemia, hyponatremia, and severe anemia, should not be ignored and should be prevented or treated immediately. (ix) Pediatric patients with an elevated perioperative risk, eg, preterm and term neonates, infants, and critically ill children, should be treated at institutions where all caregivers have sufficient expertise and continuous clinical exposure to such patients. (x) A strategy for preventing postoperative vomiting, emergence delirium, and acute pain should be a part of every anesthetic procedure.

An International, Multicenter, Observational Study of Cerebral Oxygenation during Infant and Neonatal Anesthesia

BACKGROUND

General anesthesia during infancy is associated with neurocognitive abnormalities. Potential mechanisms include anesthetic neurotoxicity, surgical disease, and cerebral hypoxia-ischemia. This study aimed to determine the incidence of low cerebral oxygenation and associated factors during general anesthesia in infants.

METHODS

This multicenter study enrolled 453 infants aged less than 6 months having general anesthesia for 30 min or more. Regional cerebral oxygenation was measured by near-infrared spectroscopy. We defined events (more than 3 min) for low cerebral oxygenation as mild (60 to 69% or 11 to 20% below baseline), moderate (50 to 59% or 21 to 30% below baseline), or severe (less than 50% or more than 30% below baseline); for low mean arterial pressure as mild (36 to 45 mmHg), moderate (26 to 35 mmHg), or severe (less than 25 mmHg); and low pulse oximetry saturation as mild (80 to 89%), moderate (70 to 79%), or severe (less than 70%).

RESULTS

The incidences of mild, moderate, and severe low cerebral oxygenation were 43%, 11%, and 2%, respectively; mild, moderate, and severe low mean arterial pressure were 62%, 36%, and 13%, respectively; and mild, moderate, and severe low arterial saturation were 15%, 4%, and 2%, respectively. Severe low oxygen saturation measured by pulse oximetry was associated with mild and moderate cerebral desaturation; American Society of Anesthesiology Physical Status III or IV versus I was associated with moderate cerebral desaturation. Severe low cerebral saturation events were too infrequent to analyze.

CONCLUSIONS

Mild and moderate low cerebral saturation occurred frequently, whereas severe low cerebral saturation was uncommon. Low mean arterial pressure was common and not well associated with low cerebral saturation. Unrecognized severe desaturation lasting 3 min or longer in infants seems unlikely to explain the subsequent development of neurocognitive abnormalities.

Differences in Blood Pressure in Infants After General Anesthesia Compared to Awake Regional Anesthesia (GAS Study-A Prospective Randomized Trial)

BACKGROUND

The General Anesthesia compared to Spinal anesthesia (GAS) study is a prospective randomized, controlled, multisite, trial designed to assess the influence of general anesthesia (GA) on neurodevelopment at 5 years of age. A secondary aim obtained from the blood pressure data of the GAS trial is to compare rates of intraoperative hypotension after anesthesia and to identify risk factors for intraoperative hypotension.

METHODS

A total of 722 infants ≤60 weeks postmenstrual age undergoing inguinal herniorrhaphy were randomized to either bupivacaine regional anesthesia (RA) or sevoflurane GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born at <26 weeks of gestation. Moderate hypotension was defined as mean arterial pressure measurement of <35 mm Hg. Any hypotension was defined as mean arterial pressure of <45 mm Hg. Epochs were defined as 5-minute measurement periods. The primary outcome was any measured hypotension <35 mm Hg from start of anesthesia to leaving the operating room. This analysis is reported primarily as intention to treat (ITT) and secondarily as per protocol.

RESULTS

The relative risk of GA compared with RA predicting any measured hypotension of <35 mm Hg from the start of anesthesia to leaving the operating room was 2.8 (confidence interval [CI], 2.0-4.1; P < .001) by ITT analysis and 4.5 (CI, 2.7-7.4, P < .001) as per protocol analysis. In the GA group, 87% and 49%, and in the RA group, 41% and 16%, exhibited any or moderate hypotension by ITT, respectively. In multivariable modeling, group assignment (GA versus RA), weight at the time of surgery, and minimal intraoperative temperature were risk factors for hypotension. Interventions for hypotension occurred more commonly in the GA group compared with the RA group (relative risk, 2.8, 95% CI, 1.7-4.4 by ITT).

CONCLUSIONS

RA reduces the incidence of hypotension and the chance of intervention to treat it compared with sevoflurane anesthesia in young infants undergoing inguinal hernia repair.

Pediatric Laparoscopy and Adaptive Oxygenation and Hemodynamic Changes

Adaptive changes in oxygenation and hemodynamics are evaluated during pediatric laparoscopy. The children underwent laparoscopy (LAP Group, n=20) or open surgery (Open Group, n=10). Regional cerebral (rScO₂) and peripheral oxygen saturation (SpO₂), heart rate (HR), diastolic (DP) and systolic pressure (SP) were monitored at different intervals: basal (T0); anesthesia induction (T1); CO₂PP insufflation (T2); surgery (T3); CO₂PP cessation (T4); before extubation (T5). At T1, in both the LAP and Open groups significant changes in rScO₂, DP and SP were recorded compared with T0; a decrease in SatO₂ was also observed at T5. In the LAP group, at T2, changes in HR related to CO₂PP pressure and in DP and SP related to IAP were noted; at T4, a SP change associated with CO₂PP desufflation was recorded. Open group, at T3 and T5 showed lower rScO₂ values compared with T1. Pneuperitoneum and anesthesia are influent to induce hemodynamics changes during laparoscopy.

Changes in cerebral oxygen saturation and haemoglobin concentration during paediatric cardiac surgery

Although near-infrared spectroscopy (NIRS) enables bedside assessment of cerebral oxygenation, it provides little information on the cause of deoxygenation. The authors aimed to investigate the changes in cerebral oxygenation and haemoglobin concentration and their associations during paediatric cardiac surgery in order to elucidate the physiology underlying cerebral deoxygenation. An observational retrospective study on 399 patients who underwent paediatric cardiac surgery was conducted. With use of NIRS, cerebral oxygen saturation as expressed by tissue oxygen index (TOI) before and after surgery, concentration changes in oxygenated haemoglobin (Δ[HbO₂]) and deoxygenated haemoglobin (Δ[HHb]) after surgery were studied as were the associations between these values and clinical variables. TOI decreased after surgery (preoperative versus postoperative value, 66.0% [56.9, 71.3] versus 63.2% [54.3, 69.4], median [25th, 75th percentile], P <0.001) and the decrease was greater in higher category groups in the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1). [HHb] increased from its baseline (+1.74 μmol/l [-1.57, +5.84], P <0.001) and the increase was greater in higher risk category groups. On the contrary, there was no evidence for a change in [HbO₂] (+0.45 μmol/l [-4.76, +5.30], P=0.42). Cerebral oxygen saturation decreased after paediatric cardiac surgery and the decrease was greater in patients of higher risk groups. The increase in [HHb] was considered to play a predominant role in the cerebral deoxygenation noted, in particular in higher RACHS-1 category groups.

Dexmedetomidine sedation combined with caudal anesthesia for lower abdominal and extremity surgery in ex-preterm and full-term infants

BACKGROUND

Awake caudal anesthesia is a potentially attractive option, because the administration of general anesthesia is associated with a high rate of respiratory complications and hemodynamic disturbances and potential neurotoxic effects. To facilitate the caudal puncture and subsequent surgical intervention, additional sedatives are commonly administered.

AIM

We aimed to establish a new, safe, and effective anesthetic procedure for very young children with comorbidities.

METHODS

We retrospectively analyzed 23 children who underwent lower abdominal or lower extremity surgery with dexmedetomidine sedation and caudal anesthesia from January 2015 to August 2015. Dexmedetomidine was initiated with a total bolus infusion of 0.7-1.1 μg·kg^-1 followed by a continuous infusion of 1 μg·kg^-1 ·h^-1 . Bupivacaine (2.5 mg·kg^-1 ) was supplemented with 5-10 μg·kg^-1 epinephrine to strengthen and prolong motor block. According to maturity at birth, two groups were defined: ex-preterm and full-term infants.

RESULTS

There were 12 ex-preterm and 10 full-term infants available for analysis. The median postmenstrual age was 44 (38-52) weeks in ex-preterm and 46.5 (40-72) weeks in full-term infants. Without any additional intervention, surgery was successfully accomplished in 82% of all cases. While respiratory complications were not a problem, hemodynamic disturbances commonly occurred. Maximum decreases in heart rate (HR) of 30% were accompanied by maximum decreases in mean arterial pressure (MAP) of 38%. No infant had a heart rate below 100 bpm. MAP declined in one ex-preterm infant to a minimum value of 32 mmHg.

CONCLUSION

Caudal anesthesia combined with dexmedetomidine sedation is an effective anesthetic technique for lower abdominal and extremity surgery in ex-preterm and full-term infants with severe comorbidities.

Defining hypotension in anesthetized infants by individual awake blood pressure values: a prospective observational study

BACKGROUND

Blood pressure (BP) is the most commonly applied clinical surrogate parameter for tissue perfusion and cerebral autoregulation. Hypotension during anesthesia may contribute to unfavorable outcome in young children. Hypotension in anesthetized infants can be defined using BP values relative to individual awake baseline or absolute BP values.

AIM

The aim of this study was to investigate the applicability of the two definitions and to compare the incidences of hypotension.

METHOD

This was a prospective observational study in 151 infants <12 months of age. The percentage of successful awake BP measurements was calculated and related to the infant's behavioral state. Hypotension under sevoflurane anesthesia was defined by a decrease of mean arterial pressure (MAP) relative to awake baseline (>20% in infants <6 months, >40% in infants >6 months) or absolute MAP values (<35 mmHg in infants <6 months, <43 mmHg in infants >6 months). The incidences of hypotension using the two definitions were compared.

RESULTS

Awake BP values were obtained in 85% of the patients. Calm patients were more likely to allow their BP to be measured than anxious patients. Anxious patients had higher preinduction MAP values than calm patients. The relative BP approach resulted in a higher incidence of postinduction hypotension than using absolute BP values.

CONCLUSIONS

Awake BP values were unobtainable in 15% of our patients, resulting in the necessity to define hypotension under anesthesia using absolute BP values. Definitions of hypotension using either absolute MAP or values relative to awake baseline are not interchangeable.

Laparoscopy in children and its impact on brain oxygenation during routine inguinal hernia repair

BACKGROUND

The systemic impact of intra-abdominal pressure (IAP) and/or changes in carbon dioxide (CO2) during laparoscopy are not yet well defined. Changes in brain oxygenation have been reported as a possible cause of cerebral hypotension and perfusion. The side effects of anaesthesia could also be involved in these changes, especially in children. To date, no data have been reported on brain oxygenation during routine laparoscopy in paediatric patients.

PATIENTS AND METHODS

Brain and peripheral oxygenation were investigated in 10 children (8 male, 2 female) who underwent elective minimally invasive surgery for inguinal hernia repair. Intraoperative transcranial near-infrared spectroscopy to assess regional cerebral oxygen saturation (rScO2), peripheral oxygen saturation using pulse oximetry and heart rate (HR) were monitored at five surgical intervals: Induction of anaesthesia (baseline T1); before CO2insufflation induced pneumoperitoneum (PP) (T2); CO2PP insufflation (T3); cessation of CO2PP (T4); before extubation (T5).

RESULTS

rScO2decreases were recorded immediately after T1 and became significant after insufflation (P = 0.006; rScO2decreased 3.6 ± 0.38%); restoration of rScO2was achieved after PP cessation (P = 0.007). The changes in rScO2were primarily due to IAP increases (P = 0.06). The HR changes were correlated to PP pressure (P < 0.001) and CO2flow rate (P = 0.001). No significant peripheral effects were noted.

CONCLUSIONS

The increase in IAP is a critical determinant in cerebral oxygenation stability during laparoscopic procedures. However, the impact of anaesthesia on adaptive changes should not be underestimated. Close monitoring and close collaboration between the members of the multidisciplinary paediatric team are essential to guarantee the patient's safety during minimally invasive surgical procedures.

The timing and prevalence of intraoperative hypotension in infants undergoing laparoscopic pyloromyotomy at a tertiary pediatric hospital

BACKGROUND

Intraoperative hypotension may be associated with adverse outcomes in children undergoing surgery. Infants and neonates under 6 months of age have less autoregulatory cerebral reserve than older infants, yet little information exists regarding when and how often intraoperative hypotension occurs in infants.

AIMS

To better understand the epidemiology of intraoperative hypotension in infants, we aimed to determine the prevalence of intraoperative hypotension in a generally uniform population of infants undergoing laparoscopic pyloromyotomy.

METHODS

Vital sign data from electronic records of infants who underwent laparoscopic pyloromyotomy with general anesthesia at a children's hospital between January 1, 1998 and October 4, 2013 were analyzed. Baseline blood pressure (BP) values and intraoperative BPs were identified during eight perioperative stages based on anesthesia event timestamps. We determined the occurrence of relative (systolic BP <20% below baseline) and absolute (mean arterial BP <35 mmHg) intraoperative hypotension within each stage.

RESULTS

A total of 735 full-term infants and 82 preterm infants met the study criteria. Relative intraoperative hypotension occurred in 77%, 72%, and 58% of infants in the 1-30, 31-60, and 61-90 days age groups, respectively. Absolute intraoperative hypotension was seen in 21%, 12%, and 4% of infants in the 1-30, 31-60, and 61-90 days age groups, respectively. Intraoperative hypotension occurred primarily during surgical prep and throughout the surgical procedure. Preterm infants had higher rates of absolute intraoperative hypotension than full-term infants.

CONCLUSIONS

Relative intraoperative hypotension was routine and absolute intraoperative hypotension was common in neonates and infants under 91 days of age. Preterm infants and infants under 61 days of age experienced the highest rates of absolute and relative intraoperative hypotension, particularly during surgical prep and throughout surgery.

Developing an objective method for analyzing vital signs changes in neonates during general anesthesia

BACKGROUND

Commonly used general anesthetics are considered to be neurotoxic to the developing rodent brain, leading to poor long-term outcome. However, it is unclear whether these rodent studies can be extrapolated to the human neonate. Given that anesthesia for urgent neonatal surgery cannot be avoided, it is vitally important to assess other factors that may impact neurological outcome following anesthesia and surgery.

OBJECTIVE

The purpose of this study is to identify thresholds for detecting vital sign deviations, which may have the potential for affecting neurological outcome following anesthesia and surgery in neonates. These data may be suitable to identify targets for prospective quality improvement projects and guide future research for strategies to reduce detrimental neurocognitive outcomes.

METHODS

A retrospective analysis of vital sign data was performed for neonates (age ≤28 days), undergoing noncardiac surgery over a 4-year period (2010-2013). Thresholds for detecting bradycardia, tachycardia, hypothermia, hyperthermia, hypertension, hypotension, hypocarbia, hypoxemia, significant changes in mean arterial blood pressure, and periods of high inspired oxygen concentration, were proposed. Selected chart review, to identify additional risk factors, and identify sources of data artifact, was performed for 224 cases.

RESULTS

Data from 435 procedures in neonates, with median (IQR [range]) ages of 6 (2-16 [0-28]) days were available for analysis. Five (3-6 [0-12]) rule deviations per case were observed; only 11 cases had no rule deviations. Hypothermia was observed in 285/435 (70%), moderate hypocapnia in 298/430 (69%), and severe hypotension in 270/435 (62%) cases.

CONCLUSION

An objective method of comparing cases has been created with a method to automatically identify neonatal vital sign deviations. With further validation the method has the potential to be a powerful tool to drive future quality improvement projects in neonatal anesthesia.

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.

Effects of hypotension and/or hypocapnia during sevoflurane anesthesia on perfusion and metabolites in the developing brain of piglets-a blinded randomized study

BACKGROUND

Hypotension (HT) and/or hypocapnia (HC) are frequent complications occurring during pediatric anesthesia and may cause cerebral injury in the developing brain.

AIM

The aim of this study is to investigate the effects of HT and/or HC on perfusion and metabolism in the developing brain.

METHODS

Twenty-eight piglets were randomly allocated to four groups: control (C), HT, HC, and hypotension and hyocapnia (HTC). Anesthesia was induced and maintained using sevoflurane. Fentanyl was added for instrumentation. Piglets were fully monitored and their lungs were artificially ventilated. Before treatment, conventional magnetic resonance imaging (MRI), dynamic susceptibility-contrast-enhanced T2*-weighted MRI (DSC-MRI), and single voxel proton MR spectroscopy ((1) H MRS) were performed. Hypotension (mean arterial blood pressure: 30 ± 3 mmHg) was induced by blood withdrawal and nitroprusside infusion, and hyperventilation was used to induce HC (PaCO2 : 2.7-3.3 kPa). (1) H MRS and DSC-MRI were repeated immediately once treatment goals were achieved and 120 min later. Radiologists were blinded to the groups. DSCI-MRI and (1) H MRS analyses were performed in the thalamus, occipital and parietal lobe, hippocampus, and watershed areas.

RESULTS

In comparison to C, mean time to peak (TTP) increased with HTC in all brain areas as assessed with DSC-MRI (n = 26). Using (1) H MRS, a significant decrease in N-acetyl aspartate, choline, and myoinositol, as well as an increase in glutamine-glutamate complex (Glx) were detected independent of group. Compared to C, changes were more pronounced for Glx (due to an increase in glutamate) and myoinositol with HTC, for N-acetyl aspartate with HT, and for Glx with HC. No lactate signal was present.

CONCLUSIONS

The combination of HT and HC during sevoflurane anesthesia resulted in alteration of cerebral perfusion with signs of neuronal dysfunction and early neuronal ischemia. HT and HC alone also resulted in signs of metabolic disturbances despite the absence of detectable cerebral perfusion alterations.

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.

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.