Charles Dean Kurth

Anesthetic management of cesarean delivery complicated by ex utero intrapartum treatment of the fetus

W ith recent developments in prenatal imaging, fetal anatomic malformations involving the airway that would previously have caused difficulty during delivery and in the postpartum period are now diagnosed antenatally. These cases present challenges not only for the obstetrician and pediatric surgeon but also for the anesthesiologist. Maternal and fetal anesthesia and safety as well as uterine relaxation must be considered in formulating an anesthetic plan. We present three cases of anesthetic management for ex utero intrapartum treatment (EXIT procedure) (1). This procedure was used to establish an airway before delivery of two fetuses with large neck masses and in one fetus for removal of a tracheal clip placed at 28 weeks for the antenatal treatment of a diaphragmatic hernia.

Supplementing desflurane with intravenous anesthesia reduces fetal cardiac dysfunction during open fetal surgery.

Objective:  To lower the incidence and severity of fetal cardiovascular depression during maternal fetal surgery under general anesthesia.

Real-Time Assessment of Perioperative Behaviors and Prediction of Perioperative Outcomes

Background and Aims: New onset maladaptive behaviors, such as temper tantrums, nightmares, bed-wetting, attention-seeking, and fear of being alone are common in children after outpatient surgery. Preoperative anxiety, fear and distress behaviors of children predict postoperative maladaptive behaviors as well as emergence delirium. Parental anxiety has also been found to influence children’s preoperative anxiety. Currently, there is no real-time and feasible tool to effectively measure perioperative behaviors of children and parents. We developed a simple and real-time scale, the Perioperative Adult Child Behavioral Interaction Scale (PACBIS) to assess perioperative child and parent behaviors that might predict postoperative problematic behavior and emergence excitement. METHODS: We used the PACBIS to evaluate perioperative behaviors during anesthetic induction and recovery in a sample of 89 children undergoing tonsillectomies and adenoidectomies, and their parents. Preoperative anxiety with the modified Yale Preoperative Anxiety Scale, compliance with induction of anesthesia with Induction Compliance Checklist, and incidence of emergence excitement were also recorded. RESULTS: The PACBIS demonstrated good concurrent validity with modified Yale Preoperative Anxiety Scale and Induction Compliance Checklist and predicted postanesthetic emergence excitement. DISCUSSION: The PACBIS is the first real-time scoring instrument that evaluates children’s and parents’ perioperative behavior. The specific behaviors identified by the PACBIS might provide targets for interventions to improve perioperative experiences and postoperative outcomes.

A randomized trial comparing sevoflurane and propofol in children undergoing MRI scans

Objectives:  We compared three primary outcomes of pausing the magnetic resonance imaging (MRI) scan, emergence quality and respiratory complications.

Cost‐effectiveness of intravenous acetaminophen for pediatric tonsillectomy

The primary outcome of this study was to examine the cost‐effectiveness of the intraoperative combination of intravenous (IV) acetaminophen and IV opioids, versus IV opioids alone, as a part of an inhalational anesthetic technique for tonsillectomy in children.

Real-Time Assessment of Perioperative Behaviors in Children and Parents: Development and Validation of the Perioperative Adult Child Behavioral Interaction Scale

BACKGROUND:Behavior in response to distressful events during outpatient pediatric surgery can contribute to postoperative maladaptive behaviors, such as temper tantrums, nightmares, bed-wetting, and attention seeking. Currently available perioperative behavioral assessment tools have limited utility in guiding interventions to ameliorate maladaptive behaviors because they cannot be used in real time, are only intended to be used during 1 phase of the experience (e.g., perioperative), or provide only a static assessment of the child (e.g., level of anxiety). A simple, reliable, real-time tool is needed to appropriately identify children and parents whose behaviors in response to distressful events at any point in the perioperative continuum could benefit from timely behavioral intervention. Our specific aims were to (1) refine the Perioperative Adult Child Behavioral Interaction Scale (PACBIS) to improve its reliability in identifying perioperative behaviors and (2) validate the refined PACBIS against several established instruments. METHODS:The PACBIS was used to assess the perioperative behaviors of 89 children aged 3 to 12 years presenting for adenotonsillectomy and their parents. Assessments using the PACBIS were made during perioperative events likely to prove distressing to children and/or parents (perioperative measurement of blood pressure, induction of anesthesia, and removal of the IV catheter before discharge). Static measurements of perioperative anxiety and behavioral compliance during anesthetic induction were made using the modified Yale Preoperative Anxiety Scale and the Induction Compliance Checklist (ICC). Each event was videotaped for later scoring using the Child-Adult Medical Procedure Interaction Scale-Short Form (CAMPIS-SF) and Observational Scale of Behavioral Distress (OSBD). Interrater reliability using linear weighted kappa (&kgr;w) and multiple validations using Spearman correlation coefficients were analyzed. RESULTS:The PACBIS demonstrated good to excellent interrater reliability, with &kgr;w ranging from 0.62 to 0.94. The Child Coping and Child Distress subscores of the PACBIS demonstrated strong concurrent correlations with the modified Yale Preoperative Anxiety Scale, ICC, CAMPIS-SF, and OSBD. The Parent Positive subscore of the PACBIS correlated strongly with the CAMPIS-SF and OSBD, whereas the Parent Negative subscore showed significant correlation with the ICC. The PACBIS has strong construct and predictive validities. CONCLUSIONS:The PACBIS is a simple, easy to use, real-time instrument to evaluate perioperative behaviors of both children and parents. It has good to excellent interrater reliability and strong concurrent validity against currently accepted scales. The PACBIS offers a means to identify maladaptive child or parental behaviors in real time, making it possible to intervene to modify such behaviors in a timely fashion.

Outcome for the extremely premature neonate: how far do we push the edge?

Significant advances in perinatal and neonatal medicine over the last 20 years and the recent emergence of fetal surgery has resulted in anesthesia providers caring for a growing number of infants born at the margin of viability. Anesthetic management in this patient population has to take into consideration the immature function of many vital organ systems as well as the effects of the underlying disease processes, which can frequently lead to severe physiological derangements. Accordingly, premature infants presenting for major surgeries early in life can represent a significant anesthetic challenge. However, even with advanced anesthetic and surgical management and optimal intensive care, extremely premature infants face substantial postoperative morbidity and mortality, as well as prolonged hospital courses. In this article, we will discuss the following questions: How far have we come in improving outcomes of extreme prematurity? And what will the future medical and societal challenges be, as we continue to redefine the limits of viability?

Maternal Pulmonary Edema During Fetoscopic Surgery

Minimally invasive fetal surgery uses small endoscopes placed percutaneously through the mothers abdominal wall in order to operate on a fetus, placenta or umbilical cord. We report a case of postoperative pulmonary edema in a mother who underwent minimally invasive fetal surgery for the treatment of twin reverse arterial perfusion sequence. The procedure involves ultrasound and fetoscopic guidance to interrupt umbilical vessel blood flow to one twin. Saline irrigation is used during the procedure to facilitate surgical exposure. We hypothesize that the pulmonary edema resulted from irrigating fluid (totaling net 8 L) absorbed i.v. through myometrial venous channels accessed by passage of the operating trocars.

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.

Staying away from the edge - cerebral oximetry guiding blood pressure management.

Neurological outcome after anesthesia and surgery in young infants has always been of interest, including hypoxia-ischemia, cardiac arrest, embolic stroke, and more recently, ‘neurotoxicity.’ While ‘neurotoxicity’ grabs the headlines, cerebral oxygenation and perfusion changes associated with anesthesia may also be a contributing factor to the neurological outcome. In this issue, Michelet et al. describe the association between blood pressure changes in infants <3 months of age having anesthesia, and changes in regional cerebral oxygen saturation (rScO2) using Near Infrared Spectroscopy (NIRS). Their study demonstrates that cerebral desaturation occurs in <10% of patients whose systolic blood pressure decline is <20% from baseline, and more than 90% whose blood pressure decline is more than 35%. Of their 60 patients, 14 (23%) demonstrated reductions of rScO2 of >20%. The authors conclude by saying that ‘maintaining systolic blood pressure within 20% of baseline values appears a valid clinical target’. An important issue is the definition of what constitutes cerebral desaturation, >20% below baseline rScO2 being the criteria used by Michelet et al. There is very little data to support any one definition in infants, in the absence of large-scale trials with long-term neurodevelopmental follow-up. Studies in piglets by Kurth et al. (1) indicated cerebral hypoxia-ischemia rScO2 thresholds of between 33% and 44%. Thus, off a baseline rScO2 of 75%, a drop of 20% still leaves a buffer before damage is likely to occur, while being large enough to eliminate monitor-based fluctuations and normal physiological variation as the cause of the drop. Another important issue is the patient population and monitoring by Michelet et al. The patients were not healthy, elective surgery patients. Almost all were at risk of pulmonary aspiration and consequently received rapid sequence induction. rScO2 values were excluded if SpO2 was <95%. Thus, cerebral desaturation might have been under reported as arterial desaturation causes cerebral desaturation. During the anesthetic, arterial pressure was monitored every 10 min, far less frequently than the 3-min standard in many countries. Thus, cerebral desaturation might have been over observed because hypotension could have been more severe from delayed treatment from infrequent arterial pressure monitoring. Is cerebral desaturation detected by NIRS linked to neurological damage in humans? The emerging answer from the pediatric cardiac surgical literature suggests the answer is a qualified yes (2), although the multitude of differences in patient and procedural risk factors and the actual cerebral saturations involved may add to this uncertainty. A ‘dose–response’ relationship must exist, with more significant desaturation, for a longer period, being associated with more neuronal damage. Researchers in this area will need to cater for both desaturation and duration, as has been recently defined and reported in a clinical trial in neonatal ICU patients (3). Up until relatively recently, the observation that ‘the infant woke up fine after my anesthetic’, has been the standard by which we have assessed neurocognitive outcomes. As we have learned that neurocognitive deficits and developmental delay are often subtle and may not manifest until school age, this offhanded qualitative approach to conclude safety and no untoward complications does not suffice today. Unfortunately not all infants do wake up fine, and low blood pressure has been implicated in the etiology of postoperative encephalopathies in six neonates (4). In less obvious cases of neurological deficit, it is not detected early on after the procedure, but may then contribute to the putative association between anesthesia and long-term neurocognitive and behavioral deficits. We have all seen substantial drops in arterial blood pressure in our patients, to which we have variably reacted, the primary question being ‘what should we aim for’. We justify our more relaxed definition of hypotension and treatment in part by referencing the reduction in cerebral metabolic rate due to anesthesia, anesthetic-related hypothermia, and our experience that the infant ‘wakes up fine’. The neuroprotection from anesthesia and mild hypothermia somehow ‘balance out’ the possibility of cerebral ischemia from hypotension. They may, but in the absence of any attempt to actually measure cerebral variables, they also may not. Cerebral perfusion and neuroprotection are affected by multiple variables in addition to blood pressure, and over-focussing on blood pressure changes may obscure other important interactions, such as cerebral oxygenation and anesthetic depth. Interpretation of the multiple variables influencing cerebral blood flow is complex, and the use of a multidimensional monitor such as NIRS may facilitate the process (5), although caution is again warranted when trying to infer the status of cerebral blood flow and autoregulation using indirect means.