Anatomic measurements of the right (RMB) and left mainstem bronchi (LMB) in infants and children have been accomplished using various modalities. The objective of the present review was to determine whether enough data were available to provide standardized lower airway dimensions in the pediatric population. For the present study, 12 studies with data of the lower pediatric airway dimensions of 1,611 children published from 1923-2020 were reviewed and analyzed. The eligible criteria included studies measuring lower airway dimensions in the pediatric population. Various techniques were used for airway measurement, with computed tomography studies being most abundant. There was a progressive increase in the size of RMB and LMB with age, with a close approximation of the LMB-to-RMB ratio across all studies. In children younger than 1 year old, the RMB and LMB diameters were between 4 and 5 mm and 3 and 5 mm, respectively. Overall, there was significant variation in the methods and modality used to obtain measurements, and therefore it was difficult to establish standardized lower airway dimensions in the pediatric population. Additional homogeneous data with standardized measurement techniques and modalities across different pediatric age groups are needed to define these dimensions further. Such data may be helpful in designing airway equipment, lung isolation devices, and airway stents.

This chapter discusses brain development with a focus on topics that are clinically relevant to the pediatric anesthesiologist. Development of the pathways and neurotransmitters involved in pain transmission is outlined in addition to an expanded focus on cerebrovascular physiology. Clinically common neurological injuries are discussed as a function of developmental stage of occurrence. The physiology of the intracranial compartment and vasculature is emphasized, as are tools that the pediatric anesthesiologist can use to prevent secondary neurological injury.

New observations from novel imaging techniques regarding the anatomy, dimensions, and shape of the pediatric airway have emerged and provide insight for potential changes in the clinical management of the airway in infants and children. These new findings are challenging the historical concepts of a funnel-shaped upper airway with the cricoid ring as the narrowest dimension. Although these tenets have been accepted and used to guide clinical practice in airway management, there are limited clinical investigations in children to support the validity of these concepts. Imaging modalities such as magnetic resonance imaging, computed tomography (CT) scanning, multi-detector CT imaging, and videobronchoscopy suggest the need to revisit the historical view of the pediatric airway. This manuscript reviews the historical evolution of pediatric airway studies, summarizes important scientific observations from recent investigations relevant to our clinical understanding of pediatric airway anatomy, and discusses the importance of these findings for pediatric airway management.

To evaluate the effects of sex on miRNA expression in the hippocampus after isoflurane anesthesia in a neonatal piglet model. Six male and 6 female piglets, aged 3–5 days, were anesthetized with 2% isoflurane in room air for 3 h. Full physiologic monitoring was observed. Untreated animals (6 male, 6 female) served as controls. Expression of miRNAs in hippocampus was assessed. In controls, miRNA expression in the hippocampus was highly conserved between males and females. However, 17/326 displayed sex-dependent differences: 10 miRNAs were more highly expressed in males; 7 showed lower expression in males than females. Isoflurane was associated with changes in the expression of distinct subsets of miRNAs in both males and females. In females, 14/326 miRNAs were significantly changed (3 downregulated; 11 upregulated); in males, 17/326 miRNAs were changed (7 downregulated; 10 upregulated). There was no overlap in significantly changed miRNAs between isoflurane-exposed males and females. In the neonatal piglet hippocampus, miRNA expression was highly conserved. There was no overlap in miRNA expression between isoflurane-exposed males and females, suggesting sex differences in isoflurane-induced miRNA expression. These results support the hypothesis that a clinically relevant exposure to isoflurane induces distinct miRNA signatures in the hippocampus of neonatal male and female piglets. Their functional relevance in anesthesia-induced neurotoxicity remains unknown, although changes in specific miRNAs may either contribute to or protect against anesthesia-induced neurotoxicity.

Background: Knowledge regarding the shape, size, and variability of the cricoid ring is important to properly choose the correct endotracheal tube (ETT) in the pediatric patient. Studies have measured the size of the cricoid ring using methodologies such as moulages, magnetic resonance imaging, and video-bronchoscopy. In the present study, computed tomography (CT)-based images were used to determine the shape, size, and configuration of the cricoid ring in the pediatric population taking into considerations growth and development.Methods: This is a retrospective review using 130 CT images of children ranging in age from 1 month to 10 years undergoing radiological evaluation unrelated to airway symptomatology. The CT scans were obtained in spontaneously breathing patients during either natural sleep or procedural sedation. Anteroposterior (AP) and transverse (T) diameters were measured at the cricoid ring using these images.Results: The cricoid ring is generally round in children older than 1 year with a T/AP ratio ranging between 0.98 and 1.01. However, in infants (1-12 months of age), the cricoid ring is elliptical with the AP dimension an average of 0.31 mm larger than the T dimension with a T/AP ratio of 0.95. A statistically significant difference between the T and AP dimensions was only observed in infancy (P < 0.05).Conclusion: The cricoid ring is round in children older than 1 year of age. In infants, the cricoid shape presents a more elliptical configuration because the T-axis is narrower than the AP dimension. CT is recognized as the most accurate technique to study cricoid ring configuration, and the present data may help clinicians determine the appropriate type, size, and shape of ETTs, particularly in infants.

Anesthesia cannot be avoided in many cases when surgery is required, particularly in children. Recent investigations in animals have raised concerns that anesthesia exposure may lead to neuronal apoptosis, known as anesthesia-induced developmental neurotoxicity (AIDN). Furthermore, some clinical studies in children have suggested that anesthesia exposure may lead to neurodevelopmental deficits later in life. Nonetheless, an ideal animal model for preclinical study has yet to be developed. The neonatal piglet represents a valuable model for preclinical study, as they share a striking number of developmental similarities with humans. The anatomy and physiology of piglets allow for implementation of rigorous human perioperative conditions in both survival and non-survival procedures. Femoral artery catheterization allows for close monitoring, thus enabling prompt correction of any deviation of the piglet's vital signs and chemistries. In addition, there are multiple developmental similarities between piglets and human neonates. The techniques required to use piglets for experimentation will require experience to master. A pediatric anesthesiologist is a critical member of the investigative team. We describe, in a general sense, the appropriate use of a piglet model for neurodevelopmental study.

To determine if isoflurane anesthesia without surgery causes systemic inflammation in children. Inflammation is targeted as responsible for the development of many neurologic pathologies. The effect will be evaluated by measuring serum cytokine levels before and after isoflurane anesthesia. The possible neurotoxic effect of anesthetic agents is a concern in pediatric anesthesia. Questions remain as to the true effects of anesthesia alone on systemic inflammation. The current study assesses systemic inflammatory response to general anesthesia in children not exposed to surgical stress.

Introduction: Although the Nuss procedure provides excellent cosmetic results for the correction of pectus excavatum, the provision of analgesia following such procedures can be challenging. Methods: The current study retrospectively reviews our experience over a 2.5 year period with thoracic epidural analgesia (TE), paravertebral blockade (PVB), and intravenous opioids delivered via patient-controlled analgesia (PCA) to provide postoperative analgesia. Results: The study cohort included 30 patients (mean age = 15.6 ± 1.5 years), 15 of whom were treated with PCA, 8 with TE, and 7 with PVB. There were no significant differences in pain scores between the 3 groups at any time point during the first 3 postoperative days. Compared to PCA, the PVB group had lower opioid consumption over the first 24 hours of hospitalization by 1.7 mg/kg morphine equivalents (95% CI of difference: 0.1, 3.3; p=0.035); but had higher opioid consumption by 2.0 mg/kg morphine equivalents than the TE group (95% CI of difference: 0.3, 3.7; p=0.024). There were no differences in opioid consumption between PVB and PCA or between PVB and TE at 48 or 72 hours. The number of intraoperative hypotension episodes was significantly lower in the PCA group when compared to the PVB group (p=0.001), with no difference between the PVB and TE groups. Conclusions: The use of regional anesthesia should be considered a viable option for the relief of postoperative pain in pediatric patients following the Nuss procedure albeit with a higher incidence of intraoperative hemodynamic effects. A randomized, prospective, study powered to compare all 3 techniques against one another would be necessary to confirm the significance of these findings.

Background: Fatigue in anesthesiologists may have implications that extend beyond individual well-being.Aim: The aim of the present study was to evaluate the impact of sleep deprivation on the reaction time in anesthesiologists either after an overnight call or regular working hours. Moderation of this effect by coping strategies was observed.Methods: Psychomotor vigilance test was used to assess reaction time in 23 anesthesiologists at two time-points: (i) on a regular non-call day and (ii) after a 17-h in-house call. Student's paired t-test was used to compare Psychomotor Vigilance Task data at these two moments. Change score regression was performed to determine the association between coping strategies, assessed using the Coping Strategy Indicator instrument, and decline in reaction time after night call.Results: Twenty-one colleagues completed the psychomotor vigilance test measurements after two decided to end their participation for personal reasons. Post-call psychomotor vigilance test mean reaction time decreased by an average of 31.2 ms (95% CI: 0.5, 61.9; P = 0.047) when compared to regular day. Reliance on specific coping mechanisms, indicated by Coping Strategy Indicator scale scores, included problem-solving (28 +/- 4), followed by seeking social support (23 +/- 5) and avoidance (19 +/- 4). The change score regression model (r(2) = 0.48) found that greater reliance on avoidance was associated with greater increase in reaction time after night call.Conclusion: Reaction time increased considerably in anesthesiologists after a night call duty. Greater subjective reliance on avoidance as a coping strategy was associated with greater deterioration in performance.

Anesthesia-induced neurotoxicity research in the developing brain must rely upon an unimpeachable animal model and a standardized treatment approach. In this manner, identification of mechanisms of action may be undertaken. The goal of this study was to develop a novel, clinically relevant, translational way to use a piglet model to investigate anesthesia effects on the developing brain.

BACKGROUND:A physician's fatigue raises significant concerns regarding personal and patient safety. Effects of sleep deprivation on clinical performance and the quality of patient care are major considerations of today's health care environment.AIM:To evaluate the impact of partial sleep deprivation after a 17-h overnight call (3 pm-7 am) on the mood status and cognitive skills of anesthesiologists in an academic clinical hospital setting, as compared to these parameters during regular working hours.METHODS:Taking circadian rhythm into account, the following measures were assessed in 21 pediatric anesthesiologists at two time points over the course of the study; (i) between 7 and 8 am on a regular non call day, and (ii) between 7 and 8 am after a 17-h in-house call (3 pm-7 am). Six mood states were assessed using the Profile of Mood States. A Total Mood Disturbance (TMD) score was obtained as the sum of all mood scores minus vigor. The total score provides a global estimate of affective state. Simple cognitive tests were similarly administered to assess cognitive skills. A two-tailed paired t-test was used to compare data between regular and post call days. A P < 0.05 was used.RESULTS:The study cohort included 21 pediatric anesthesiologists at a tertiary care children's hospital. Tension, anger, fatigue, confusion, TMD, irritability, feeling jittery, and sleepiness were significantly affected (P < 0.05). A decrease in vigor, energy, and confidence was observed after a night call shift (P < 0.05). There was also a decrease in being "talkative" after the call shift (P < 0.05).CONCLUSION:Partial sleep deprivation affects the total mood status of anesthesiologists and impacts their cognitive skills. These findings are particularly relevant in a context of increased work expectation, particularly on clinical performance in our modern medical system. Such observations suggest that there may be changes that impact the safety of our patients and the quality of health care that is provided.

BACKGROUND:Recent studies have challenged the historically accepted fact that the larynx is cone-shaped in infants and children. The present study used computed tomography (CT)-based measurements to evaluate airway dimensions. The purpose of this investigation was to determine the dimensional transition between the subglottic area and the cricoid ring in children. METHODS:This is a retrospective review of 220 CT scans of children aged 1 month to 10 years undergoing radiological evaluation unrelated to airways symptomatology. The CT scans were evaluated in children either sleeping naturally or sedated throughout the study period. Anteroposterior (AP) and Transverse (T) diameters were measured at the subglottic level and at the cricoid ring. RESULTS:The mean (±SD) age was 47.4 ± 33.1 months. The mean AP and transverse diameters were 9.2 ± 1.9 and 7.5 ± 1.6 mm at the subglottic area and 8.5 ± 1.7 and 8.3 ± 1.5 mm at the cricoid. AP dimension showed a decrease from the subglottis to the cricoid ring. A more rapid enlargement of the airway from the subglottis to cricoid ring is observed in the transverse dimension (P < 0.05). A linear progression in the size of airway dimensions between both levels was observed with age (r > 0.7). CONCLUSION:The narrower transverse dimension compared to the AP diameter suggests that the airway is elliptical immediately below the vocal cords. The present study demonstrates that the airway characteristics in children between the subglottic area and the cricoid change from an elliptical to a round (circular) shape. The cone-shaped airway characteristic, which has been historically proposed, was not observed. Given that subglottic transverse diameter is the smallest area dimension, one must assume this is the most likely area of resistance to the passage of an endotracheal tube rather than only the cricoid.

Background First generation cephalosporins are commonly used as antibiotic prophylaxis prior to surgery. Patients labeled as penicillin-allergic are often precluded from receiving cephalosporins because of an allergic cross-reactivity. The aims of this study were to evaluate the clinical practice for surgical prophylaxis at Nationwide Children's Hospital and to determine the incidence of adverse effects and allergic reactions when using cephalosporins in patients labeled as penicillin-allergic. Methods A retrospective chart review was performed to identify patients who were allergic to penicillin, penicillin antibiotic family, who required surgical treatment for an existing medical condition, and received an antibiotic to prevent surgical site infection. Results Five hundred thirteen penicillin-allergic patients were identified, encompassing 624 surgical cases. Cephalosporins were administered in 153 cases (24.5%) with cefazolin used 83% of the time. Only one documented case of nonanaphylactic reaction was reported. Clindamycin was the most common cephalosporin substitute (n = 387), and the reported adverse reaction rate was 1.5%. No cases of anaphylaxis were documented. Conclusions Our data suggest that the administration of cephalosporins for surgical prophylaxis following induction of anesthesia in a patient with a known or reported penicillin-allergy appears appropriate and results in a lower adverse event rate that when clindamycin is administered.

The aim of this study was to evaluate the response of pleth variability index (PVI) to phlebotomy in anesthetized children prior to surgery for congenital heart disease. After induction of general anesthesia and prior to surgical incision, approximately 10 mL/kg of blood was removed from 40 mechanically ventilated children over a 5-10 min period. The PVI was continuously monitored. Additionally, the volume of crystalloid required to ensure hemodynamic and near infrared spectroscopy stability was recorded. There was no difference between the pre-phlebotomy PVI (13% ± 6.2) and the post-phlebotomy PVI (16.4% ± 9.6) (P = 0.55). Patients who had a starting PVI ≤14% had a significant increase in PVI after phlebotomy from 9.1% ± 3 to 14.3% ± 7.2 (P = 0.0014). Although, patients with a pre-phlebotomy PVI of >14% required more crystalloid replacement (11 ± 9.4 mL/kg) than those with a PVI ≤14% (5.3 ± 4.7 mL/kg), this was not significant (P = 0.06). In patients who received less crystalloid replacement during phlebotomy, PVI did show a significant increase. Additionally, the data suggests that patients with a pre-phlebotomy PVI >14% required greater fluid replacement than those with a PVI < 14%. Further research is needed to better delineate the utility of PVI in this unique group of patients.

Pediatric AnesthesiaVolume 24, Issue 2 p. 224-225 Correspondence Response of Dr. Ho's comments Markus Weiss, Markus Weiss [email protected] Department of Anaesthesia, University Children's Hospital Zurich, Zurich, SwitzerlandSearch for more papers by this authorThomas Engelhardt, Thomas Engelhardt Department of Anesthesia, Royal Aberdeen Children's Hospital, Aberdeen, UKSearch for more papers by this authorBruno Bissonnette, Bruno Bissonnette Department of Anesthesiology and Pain Medicine, Nationwide Children's, Columbus, OH, USASearch for more papers by this authorSulpicio Soriano, Sulpicio Soriano Department of Anesthesia, Boston Children's Hospital, Harvard Medical School, Boston, MA, USASearch for more papers by this author Markus Weiss, Markus Weiss [email protected] Department of Anaesthesia, University Children's Hospital Zurich, Zurich, SwitzerlandSearch for more papers by this authorThomas Engelhardt, Thomas Engelhardt Department of Anesthesia, Royal Aberdeen Children's Hospital, Aberdeen, UKSearch for more papers by this authorBruno Bissonnette, Bruno Bissonnette Department of Anesthesiology and Pain Medicine, Nationwide Children's, Columbus, OH, USASearch for more papers by this authorSulpicio Soriano, Sulpicio Soriano Department of Anesthesia, Boston Children's Hospital, Harvard Medical School, Boston, MA, USASearch for more papers by this author First published: 06 January 2014 https://doi.org/10.1111/pan.12317Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume24, Issue2February 2014Pages 224-225 RelatedInformation

BACKGROUND:Normovolemic hemodilution (HD) in adult animal studies has shown exacerbation of traumatic brain injury (TBI) lesion volumes. Similar studies in juvenile rats have not been reported and outcomes are likely to be different. This study investigated the effects of normovolemic hemodilution (21% hematocrit) in a juvenile TBI (jTBI) model. METHODS:Twenty 17-day-old rats underwent moderate cortical contusion impact injury (CCI) and were divided into four groups: CCI/hemodilution (HD) (group HD), CCI/no HD (group C), Sham/HD (group SHD), and Sham/no HD (group S). Regional laser Doppler flowmetry (LDF), edema formation (MRI-T2WI), water mobility assessed using diffusion weighted imaging (MRI-DWI), open field activity tests, and histological analyses were evaluated for lesion characteristics. RESULTS:Hemodilution significantly increased blood flow in the HD compared to the C group after TBI. T2WI revealed a significantly increased extravascular blood volume in HD at 1, 7, and 14 days post-CCI. Edematous tissue and total contusional lesion volume were higher in HD-treated animals at 1 and 14 days. DWI revealed that HD, SHD, and C groups had elevated water mobility compared to S groups in the ipsilateral cortex and striatum. Histology showed a larger cortical lesion in the C than HD group. Open field activity was increased in HD, C, and SHD groups compared to the S group. CONCLUSIONS:Hemodilution results in significant brain hyperemia with increased edema formation, extravascular blood volume, and water mobility after jTBI. Hemodilution results in less cortical damage but did not alter behavior. Hemodilution is likely not to be clinically beneficial following jTBI.

Neurological insults are a leading cause of morbidity and mortality, both in adults and especially in children. Among possible therapeutic strategies to limit clinical cerebral damage and improve outcomes, hypothermia remains a promising and beneficial approach. However, its advantages are still debated after decades of use. Studies in adults have generated conflicting results, whereas in children recent data even suggest that hypothermia may be detrimental. Is it because brain temperature physiology is not well understood and/or not applied properly, that hypothermia fails to convince clinicians of its potential benefits? Or is it because hypothermia is not, as believed, the optimal strategy to improve outcome in patients affected with an acute neurological insult? This review article should help to explain the fundamental physiological principles of brain heat production, distribution and elimination under normal conditions and discuss why hypothermia cannot yet be recommended routinely in the management of children affected with various neurological insults.