Intraoperative hypotension in neonates

Propofol and thiopental for intravenous induction in neonates: Study protocol for a dose-finding trial

BACKGROUND

Propofol and thiopental are commonly used induction agents in neonatal anesthesia. Even though both hypnotics have been used off-label for many years, pharmacological knowledge regarding these agents is scarce in neonates. The significant variability in neonates' body composition, organ function, and maturation makes pharmacological studies highly relevant albeit challenging. As a result, there is currently limited data about the anesthetic induction dose of thiopental and propofol in neonates. In addition, a knowledge gap exists concerning the pharmacodynamics of induction doses.

OBJECTIVE

To determine the median effective anesthetic induction dose of propofol and thiopental in neonatal patients of different gestational and postnatal ages and evaluate the pharmacodynamics of the anesthesia induction doses on the neonatal systemic and cerebral hemodynamics.

METHODS

This is a single-center, prospective, open-label, interventional, dose-finding study, including neonatal patients from birth up to 28 postnatal days undergoing general anesthesia for surgical or diagnostic procedures. The patients will be stratified according to their gestational and postnatal age and allocated to one of the two trial arms: anesthesia induction with propofol or anesthesia induction with thiopental. We will use Dixon's up-and-down method to estimate the median effective anesthesia induction dose of both agents in neonates of different gestational and postnatal ages. In addition, we will study the relationship between anesthesia induction doses and changes in systemic and cerebral hemodynamics.

DISCUSSION

Alterations in the systemic and cerebral regional hemodynamics secondary to anesthesia induction may be harmful in neonates, especially premature and critically ill newborns, due to their immature organ systems, reduced physiological reserves, and impaired cerebral autoregulation. Perfusion homeostasis is considered one of the significant and modifiable determinants of anesthesia-related neurocognitive outcomes. Therefore, dose-finding and safety pharmacological studies of the anesthetic induction agents in neonates are urgently needed and acknowledged as a high priority by the European Medicine Agency. Estimating adequate induction doses to ensure optimal depth of anesthesia while avoiding systemic and cerebral hemodynamic disturbances will help ensure safe anesthesia and potentially improve anesthesia-related outcomes in this group of patients.

TRIAL REGISTRATION

EudraCT (EudraCT Identifier: 2019-001534-34), 05.07.2022.

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.

After nectarine: how should we provide anesthesia for neonates?

PURPOSE OF REVIEW

Neonates have a high risk of perioperative morbidity and mortality. The NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE) investigated the anesthesia practice, complications and perioperative morbidity and mortality in neonates and infants <60 weeks post menstrual age requiring anesthesia across 165 European hospitals. The goal of this review is to highlight recent publications in the context of the NECTARINE findings and subsequent changes in clinical practice.

RECENT FINDINGS

A perioperative triad of hypoxia, anemia, and hypotension is associated with an increased overall mortality at 30 days. Hypoxia is frequent at induction and during maintenance of anesthesia and is commonly addressed once oxygen saturation fall below 85%.Blood transfusion practices vary widely variable among anesthesiologists and blood pressure is only a poor surrogate of tissue perfusion. Newer technologies, whereas acknowledging important limitations, may represent the currently best tools available to monitor tissue perfusion. Harmonization of pediatric anesthesia education and training, development of evidence-based practice guidelines, and provision of centralized care appear to be paramount as well as pediatric center referrals and international data collection networks.

SUMMARY

The NECTARINE provided new insights into European neonatal anesthesia practice and subsequent morbidity and mortality.Maintenance of physiological homeostasis, optimization of oxygen delivery by avoiding the triad of hypotension, hypoxia, and anemia are the main factors to reduce morbidity and mortality. Underlying and preexisting conditions such as prematurity, congenital abnormalities carry high risk of morbidity and mortality and require specialist care in pediatric referral centers.

Risk factors for anesthesia-associated postoperative capillary leakage after thoracoscopic surgery in neonates: A single-center observational study

BACKGROUND

Thoracoscopy is considered the surgical method of choice for addressing a wide range of conditions in neonates. However, there is a lack of experience in anesthesia management for this procedure. On reviewing the newborns who had undergone thoracoscopic surgery at our medical center, some had developed edema after surgery. After excluding other etiologies, these neonates were diagnosed with capillary leakage secondary to thoracoscopy.

AIMS

This study aimed to identify the potential risk factors for capillary leakage secondary to thoracoscopy in neonates and to provide reference information for optimal anesthesia management.

METHODS

This single-center, retrospective, observational study examined neonates who had undergone thoracoscopic surgery between January 1, 2018, and September 31, 2021. Their electronic medical records were analyzed for demographic and clinical characteristics associated with anesthesia, and postoperative capillary leakage occurring within 24 and 48 h of surgery was assessed based on medical records.

RESULTS

A total of 56 neonates that underwent thoracoscopic surgery were included in this study. Postoperative capillary leakage within 24 h was diagnosed in 14 neonates (25%). The partial pressure of carbon dioxide was an independent factor influencing the occurrence of postoperative edema within 24 h (P = 0.021). Overall, 21 cases (37.5%) were diagnosed as postoperative capillary leakage within 48 h, and age was an independent factor influencing the occurrence of postoperative edema within 48 h (P = 0.027).

CONCLUSIONS

According to our findings, we concluded that preventing the elevation of the partial pressure of carbon dioxide may reduce the occurrence of secondary capillary leakage within 24 h after thoracoscopic surgery, and that older newborns are less likely to have secondary capillary leakage within 48 h after thoracoscopic surgery. Our findings provide evidence that directly informs anesthesia management for thoracoscopic surgery in neonates.

CLINICAL TRIAL REGISTRATION

The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100054117).

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.

[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.

Anesthesia for bilateral pulmonary banding as part of hybrid stage I approach palliating neonates with hypoplastic left heart syndrome

BACKGROUND

Neonatal management of patients with hypoplastic left heart syndrome and complex remains a challenging task, whereby the "hybrid" palliation is often reserved for high-risk patients as a "rescue" procedure.

AIM

This study documents the anesthetic challenges and potential complications associated with the Giessen hybrid stage I approach.

METHODS

The Giessen hybrid stage I approach is focused on surgical bilateral pulmonary artery banding. Retrospective perioperative data were analyzed. Contrary to a stable group A, inotropic treatment before surgery for treatment of postnatal shock classified patients as unstable (Group B). Clinical outcomes considered were inhospital mortality, duration of postoperative mechanical ventilation, postoperative time at the intensive care unit, perioperative vasoactive medication requirements, and red blood cell transfusion.

RESULTS

From June 1998 to December 2015, 185 patients were allocated to Group A (n = 165) and Group B (n = 20). The inhospital mortality was 2.2% with no difference between the groups. There was also no difference in the postoperative time on mechanical ventilation and the time in the intensive care unit. Vasoactive medication was more often required in Group B (100%) compared to Group A (19%). In Group B, more red blood cells were transfused 6.0 ± 8.3 vs 2.0 ± 5.8 mL/kg in Group A (P < .05, 95% CI 0.0 - 2.6).

CONCLUSION

Considering a learning curve, anesthesia for surgical bilateral pulmonary artery banding palliating patients with hypoplastic left heart syndrome and complex can safely be performed, independent from the preoperative clinical status.

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.

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.

Neonatal anesthesia: how we manage our most vulnerable patients

Neonates undergoing surgery are at higher risk than older children for anesthesia-related adverse events. During the perioperative period, the maintenance of optimal hemodynamics in these patients is challenging and requires a thorough understanding of neonatal physiology and pharmacology. Data from animals and human cohort studies have shown relation of the currently used anesthetics may associate with neurotoxic brain injury that lead to later neurodevelopmental impairment in the developing brain. In this review, the unique neonatal physiologic and pharmacologic features and anesthesia-related neurotoxicity will be discussed.