Induction of anesthesia with sevoflurane in children: Curiosities and controversies.

Inhalational inductions with sevoflurane (up to 8% inspired concentration) have been the standard for inducing anesthesia in children for over three decades. However, when sevoflurane was first introduced, clinicians reported isolated cases of unexpected myoclonic jerking movements during the induction in children without epilepsy. These cases raised concerns regarding the widespread use of sevoflurane particularly after reports of seizures and epileptiform electroencephalographic (EEG) discharges surfaced. The latter reports prompted recommendations to reduce the concentration of sevoflurane during induction of anesthesia. More recently, a shift away from the use of nitrous oxide has prompted some to question whether sevoflurane has a role as an induction agent in children. The preponderance of evidence supports the practice of safely inducing anesthesia with 8% sevoflurane with or without nitrous oxide in children but recommended strategies to mitigate against epileptiform discharges may be more harmful than beneficial.

Pro-Con Debate: 1- vs 2-Hour Fast for Clear Liquids Before Anesthesia in Children.

Perioperative fasting guidelines are designed to minimize the risk of pulmonary aspiration of gastrointestinal contents. The current recommendations from the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology and Intensive Care (ESAIC) are for a minimum 2-hour fast after ingestion of clear liquids before general anesthesia, regional anesthesia, or procedural sedation and analgesia. Nonetheless, in children, fasting guidelines also have consequences as regards to child and parent satisfaction, hemodynamic stability, the ability to achieve vascular access, and perioperative energy balance. Despite the fact that current guidelines recommend a relatively short fasting time for clear fluids of 2 hours, the actual duration of fasting time can be significantly longer. This may be the result of deficiencies in communication regarding the duration of the ongoing fasting interval as the schedule changes in a busy operating room as well as to poor parent and patient adherence to the 2-hour guidelines. Prolonged fasting can result in children arriving in the operating room for an elective procedure being thirsty, hungry, and generally in an uncomfortable state. Furthermore, prolonged fasting may adversely affect hemodynamic stability and can result in parental dissatisfaction with the perioperative experience. In this PRO and CON presentation, the authors debate the premise that reducing the nominal minimum fasting time from 2 hours to 1 hour can reduce the incidence of prolonged fasting and provide significant benefits to children, with no increased risks.

The Effects of a Shoulder Roll During Laryngoscopy in Infants: A Randomized, Single-Blinded, Crossover Study.

BACKGROUND: The use of a shoulder roll to view the glottic opening during direct laryngoscopy in infants has been recommended but is not evidence based. METHODS: Twenty infants with normal airways, <6 months of age undergoing elective surgery under general anesthesia were randomized to undergo direct laryngoscopy first with a 2-inch vertical shoulder roll and then without, or vice versa. The primary outcome was the difference in the vertical distance between the angle of the laryngoscopist's eye and the operating room table in the 2 positions. Also, the views of the glottic opening in both positions were recorded for each infant and analyzed by a blinded investigator using the percent of glottic opening (POGO). RESULTS: Twenty infants completed the study without complications. The vertical distance did not differ significantly whether the shoulder roll was placed first or second, and there was no evidence of a differential carryover effect in the crossover design (P = .268). The main effect of the shoulder roll on the mean (95% confidence interval [CI]) vertical distances without 47.8 cm (43.5-52.1) and with the shoulder roll 37.2 cm (33.3-41) yielded a mean (95% CI) vertical difference of 10.6 cm (9.3-11.79; P = .0001). The median (interquartile range [IQR]) POGO scores without 100 [86.2, 100] and with the shoulder roll 97.5 [80, 100] did not differ (median difference [95% CI]: 0 [-20 to 0]; P = .39). CONCLUSIONS: A 2-inch shoulder roll lowers the line of sight of the glottic opening compared with no shoulder roll, without affecting the view of the glottic opening during laryngoscopy in infants.

Drug Calculation Errors in Anesthesiology Residents and Faculty: An Analysis of Contributing Factors.

BACKGROUND: Limited data exist regarding computational drug error rates in anesthesia residents and faculty. We investigated the frequency and magnitude of computational errors in a sample of anesthesia residents and faculty. METHODS: With institutional review board approval from 7 academic institutions in the United States, a 15-question computational test was distributed during rounds. Error rates and the magnitude of the errors were analyzed according to resident versus faculty, years of practice (or residency training), duration of sleep, type of question, and institution. RESULTS: A total of 371 completed the test: 209 residents and 162 faculty. Both groups committed 2 errors (median value) per test, for a mean error rate of 17.0%. Twenty percent of residents and 25% of faculty scored 100% correct answers. The error rate for postgraduate year 2 residents was less than for postgraduate year 1 (P = .012). The error rate for faculty increased with years of experience, with a weak correlation (R = 0.22; P = .007). The error rates were independent of the number of hours of sleep. The error rate for percentage-type questions was greater than for rate, dose, and ratio questions (P = .001). The error rates varied with the number of operations needed to calculate the answer (P < .001). The frequency of large errors (100-fold greater or less than the correct answer) by residents was twice that of faculty. Error rates varied among institutions ranged from 12% to 22% (P = .021). CONCLUSIONS: Anesthesiology residents and faculty erred frequently on a computational test, with junior residents and faculty with more experience committing errors more frequently. Residents committed more serious errors twice as frequently as faculty.

Pediatric ambulatory anesthesia: an update.

PURPOSE OF REVIEW: Ambulatory surgery is the standard for the majority of pediatric surgery in 2019 and adenotonsillectomy is the second most common ambulatory surgery in children so it is an apt paradigm. Preparing and managing these children as ambulatory patients requires a thorough understanding of the current literature. RECENT FINDINGS: The criteria for undertaking pediatric adenotonsillectomy on an ambulatory basis, fasting after clear fluids, postoperative nausea and vomiting (PONV), perioperative pain management and discharge criteria comprise the themes addressed in this review. SUMMARY: Three criteria determine suitability of adenotonsillectomy surgery on an ambulatory basis: the child's age, comorbidities and the severity of the obstructive sleep apnea syndrome (OSAS). Diagnosing OSAS in children has proven to be a challenge resulting in alternate, noninvasive techniques, which show promise. Abbreviating the 2 h clear fluid fasting guideline has garnered attention, although the primary issue is that parents do not follow the current clear fluid fasting regimen and until that is resolved, consistent fasting after clear fluids will remain elusive. PONV requires aggressive prophylactic measures that fail in too many children. The importance of unrecognized genetic polymorphisms in PONV despite prophylactic treatment is understated as are the future roles of palonosetron and Neurokinin-1 receptor antagonists that may completely eradicate PONV when combined with dexamethasone. Pain management requires test doses of opioids intraoperatively in children with OSAS and nocturnal desaturation to identify those with reduced opioid dosing thresholds, an uncommon practice as yet. Furthermore, postdischarge nonsteroidal anti-inflammatory agents as well as other pain management strategies should replace oral opioids to prevent respiratory arrests in those who are ultra-rapid CYP2D6 metabolizers. Finally, discharge criteria are evolving and physiological-based criteria should replace time-based, reducing the risk of readmission.

Evaluating Patient-Centered Outcomes in Clinical Trials of Procedural Sedation, Part 2 Safety: Sedation Consortium on Endpoints and Procedures for Treatment, Education, and Research Recommendations.

The Sedation Consortium on Endpoints and Procedures for Treatment, Education, and Research, established by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks, a public-private partnership with the US Food and Drug Administration, convened a second meeting of sedation experts from a variety of clinical specialties and research backgrounds to develop recommendations for procedural sedation research. The previous meeting addressed efficacy and patient- and/or family-centered outcomes. This meeting addressed issues of safety, which was defined as "the avoidance of physical or psychological harm." A literature review identified 133 articles addressing safety measures in procedural sedation clinical trials. After basic reporting of vital signs, the most commonly measured safety parameter was oxygen saturation. Adverse events were inconsistently defined throughout the studies. Only 6 of the 133 studies used a previously validated measure of safety. The meeting identified methodological problems associated with measuring infrequent adverse events. With a consensus discussion, a set of core and supplemental measures were recommended to code for safety in future procedural clinical trials. When adopted, these measures should improve the integration of safety data across studies and facilitate comparisons in systematic reviews and meta-analyses.

Perioperative considerations for airway management and drug dosing in obese children.

PURPOSE OF REVIEW: Childhood obesity, a phenomenon that is increasing globally, holds substantial relevance for pediatric anesthesia. In particular, understanding the nuances of airway management and drug dosing in obese children can be daunting. RECENT FINDINGS: Respiratory adverse events and challenges in managing the airway may be anticipated. In addition, drug-dosing strategies for the obese child are complex and poorly understood although recent advances have clarified the optimal dosing for anesthetics in these children. SUMMARY: Theoretical knowledge, practical skills, meticulous risk stratification and optimal drug regimens are crucial to ensure the safe conduct of anesthesia for obese children.

Evaluating Patient-Centered Outcomes in Clinical Trials of Procedural Sedation, Part 1 Efficacy: Sedation Consortium on Endpoints and Procedures for Treatment, Education, and Research Recommendations.

The Sedation Consortium on Endpoints and Procedures for Treatment, Education, and Research, established by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks public-private partnership with the US Food and Drug Administration, convened a meeting of sedation experts from a variety of clinical specialties and research backgrounds with the objective of developing recommendations for procedural sedation research. Four core outcome domains were recommended for consideration in sedation clinical trials: (1) safety, (2) efficacy, (3) patient-centered and/or family-centered outcomes, and (4) efficiency. This meeting identified core outcome measures within the efficacy and patient-centered and/or family-centered domains. Safety will be addressed in a subsequent meeting, and efficiency will not be addressed at this time. These measures encompass depth and levels of sedation, proceduralist and patient satisfaction, patient recall, and degree of pain experienced. Consistent use of the recommended outcome measures will facilitate the comprehensive reporting across sedation trials, along with meaningful comparisons among studies and interventions in systematic reviews and meta-analyses.

Pediatric sleep-disordered breathing: an update on diagnostic testing.

PURPOSE OF REVIEW: Recent advances in diagnostic testing for obstructive sleep apnea in children have refined the standard tests while identifying several new tools that hold promise to radically change how we diagnose sleep apnea. RECENT FINDINGS: Studies have demonstrated that the polysomnogram may be modified to permit home assessment of sleep disturbed breathing in children to ensure more widespread access to the test. Alternately, questionnaires, nocturnal oximetry, and diagnostic urinary biomarkers have shown great promise as both sensitive and specific tools to diagnose sleep apnea in children as well as track the severity of the disease. SUMMARY: The gold standard polysomnogram has been refined to permit its application in a modified form at home and for brief examinations in children. This standard has been challenged on several fronts, including questionnaires, nocturnal oximetry, drug-induced sleep endoscopy, and noninvasive urinary biomarkers that may ultimately supplant polysomnography as the gold standard to diagnose obstructive sleep apnea syndrome in children.

Linshom respiratory monitoring device: a novel temperature-based respiratory monitor.

PURPOSE: We sought to develop a temperature-based respiratory instrument to measure respiration noninvasively outside critical care settings. METHOD: Respiratory temperature profiles were recorded using a temperature-based noninvasive instrument comprised of three rapid responding medical-grade thermistors-two in close proximity to the mouth/nose (sensors) and one remote to the airway (reference). The effect of the gas flow rate on the amplitude of the tracings was determined. The temperature-based instrument, the Linshom Respiratory Monitoring Device (LRMD) was mounted to a face mask and positioned on a mannequin face. Respiratory rates of 5-40 breaths·min(-1) were then delivered to the mannequin face in random order using artificial bellows (IngMar Lung Model). Data from the sensors were collected and compared with the bellows rates using least squares linear regression and coefficient of determination. The investigators breathed at fixed rates of 0-60 breaths·min(-1) in synchrony with a metronome as their respiratory temperature profiles were recorded from sensors mounted to either a face mask or nasal prongs. The recordings were compared with a contemporaneously recorded sidestream capnogram from a CARESCAPE GEB450 Monitor. The extracted respiratory rates from the LRMD tracings and capnograms were compared using linear regression with a coefficient of determination and a Bland-Altman plot. RESULTS: The amplitude of the sensor tracings was independent of the oxygen flow rate. Respiratory rates from the new temperature-based sensor were synchronous and correlated identically with both the artificial bellows (r(2) = 0.9997) and the capnometer mounted to both the face mask and nasal prongs (r(2) = 0.99; bias = -0.17; 95% confidence interval, -2.15 to 1.8). CONCLUSIONS: Respiratory rates using the LRMD, a novel temperature-based respiratory instrument, were consistent with those using capnometry.

RéSUMé: OBJECTIF: Nous avons tenté de mettre au point un instrument respiratoire se fondant sur la température afin de mesurer la respiration de façon non invasive en dehors des unités de soins critiques. MéTHODE: Les profils de température respiratoire ont été enregistrés à l'aide d'un instrument non invasif se fondant sur la température et composé de trois thermistances de qualité médicale à réponse rapide ­ deux à proximité de la bouche et du nez (capteurs) et un troisième à l'écart des voies aériennes (référence). L'effet du débit gazeux sur l'amplitude des tracés a été déterminé. L'instrument fondé sur la température, nommément le dispositif de monitorage respiratoire Linshom (LRMD), a été fixé à un masque facial et positionné sur le visage d'un mannequin. Des fréquences respiratoires de 5-40 respirations·min−1 ont ensuite été livrées au visage du mannequin dans un ordre aléatoire à l'aide de soufflets artificiels (modèle de poumon IngMar). Les données des capteurs ont été colligées et comparées aux fréquences des soufflets à l'aide d'une méthode de régression linéaire des moindres carrés et d'un coefficient de détermination. Les chercheurs ont respiré à des fréquences fixes de 0-60 respirations·min−1 en synchronie avec un métronome pendant que leurs profils de température respiratoire étaient enregistrés par des capteurs fixés à un masque facial ou à des canules nasales. Les enregistrements ont été comparés à un tracé de capnogramme latéral enregistré simultanément par un moniteur CARESCAPE GEB450. Les fréquences respiratoires extraites des tracés du LRMD et des capnogrammes ont été comparées à l'aide d'une méthode de régression linéaire avec un coefficient de détermination et un graphique de Bland-Altman. RéSULTATS: L'amplitude des tracés des capteurs était indépendante du débit d'oxygène. Les fréquences respiratoires du nouveau capteur basé sur la température étaient synchrones et identiquement corrélées aux soufflets artificiels (r2 = 0,9997) et au capnomètre fixé au masque facial et aux canules nasales (r2 = 0,99; biais = −0,17; intervalle de confiance 95 %, −2,15 à 1,8). CONCLUSION: Les fréquences respiratoires mesurées à l'aide du LRMD, un nouvel instrument respiratoire fondé sur la température, étaient cohérentes à celles mesurées par capnométrie.

Stridor in Neonates After Using the Microcuff® and Uncuffed Tracheal Tubes: A Retrospective Review.

BACKGROUND: We conducted a retrospective chart review to determine the frequency of stridor and contributing factors after the use of Microcuff® and uncuffed tracheal tubes (TTs) in neonates. METHODS: All neonates in our neonatal intensive care unit whose airways were intubated between May 2011 and June 2012 were included. Data were collected from the neonatal intensive care unit database and from the electronic anesthesia record. Extracted data included postmenstrual age (PMA) at birth, birth weight, TT size and type, duration of tracheal intubation, and number of reintubations. The use of racemic epinephrine, heliox, and/or dexamethasone postextubation was considered diagnostic of stridor. RESULTS: Of the 324 neonates whose data were reviewed, 27 (8.3%) developed postextubation stridor. Neonates who developed stridor were more premature (PMA at birth, 29.9 ± 5.8 vs 33.0 ± 4.8 weeks, P = 0.001), had a lower birth weight (1.56 ± 1.07 vs 2.02 ± 0.96 kg, P = 0.005), greater duration of intubation (median: 20 vs 3 days, P < 0.0001), and multiple reintubations (median: 2 vs 0, P < 0.0001). The frequency of stridor was 17.2% after using Microcuff TT and 7.5% after using uncuffed TTs (Fisher exact test, 2-sided P = 0.08 [95% confidence interval for difference in proportions: -9.4% to 28.7%]). In a multivariable logistic regression model, after adjusting for PMA, birth weight, duration of intubation, and number of reintubations, the use of a Microcuff TT was associated with increased odds of stridor (adjusted odds ratio = 9.27 [95% confidence interval: 1.88-45.67], P = 0.006). CONCLUSIONS: The use of the Microcuff TT is associated with increased odds of postextubation stridor in neonates compared with the use of uncuffed TT.

Propofol anesthesia for children undergoing magnetic resonance imaging: a comparison with isoflurane, nitrous oxide, and a laryngeal mask airway.

BACKGROUND: Both propofol infusions with oxygen delivered through nasal cannula and isoflurane/N2O (nitrous oxide) delivered via a laryngeal mask airway (LMA) are used to provide anesthesia for children undergoing magnetic resonance imaging scans. We compared the incidence of adverse events and perioperative physiologic responses in children anesthetized with these 2 regimens. METHODS: One hundred-fifty healthy children, ages 1 to 10 years, were randomized to receive either a propofol infusion (starting at 300 µg kg·min) with oxygen via nasal cannula (n = 75) or isoflurane with 70% N2O in oxygen delivered via an LMA (n = 75), both after a sevoflurane/N2O/oxygen induction. Adverse airway events, as well as hemodynamic, respiratory, and other physiologic responses were recorded during the magnetic resonance imaging scans and in the postanesthesia care unit by a single research nurse who was blind to the treatments. All parents were contacted postoperatively to complete a postanesthetic follow-up. RESULTS: All 150 children completed their scans. The frequency of all adverse airway events during emergence and recovery after propofol (12%) was significantly less than that after isoflurane/N2O/LMA (49%) (95% confidence interval for the risk difference was 23%-50%) (P = 0.0001). Hemodynamic responses and recovery times for the 2 treatments were similar. Early recovery, defined as the time interval from admission to the postanesthesia care unit until eye opening and wakefulness (modified Aldrete score >5), after propofol was more rapid than that after isoflurane/N2O/LMA (P = 0.0001 and P = 0.0012, respectively). No scans had to be repeated. CONCLUSIONS: The frequency of adverse airway events during emergence and recovery after propofol infusion with oxygen by nasal cannula is less than with isoflurane/N2O/LMA in children.

Hemodynamic response to fluid management in children undergoing dexmedetomidine sedation for MRI.

OBJECTIVE: Dexmedetomidine is administered for pediatric sedation for MRI studies. It has the advantage of preserving respiratory function and producing a sedation state identical to that of natural sleep. It can, however, cause a dose-dependent decrease in systemic blood pressure in children. The purpose of this study was to investigate whether i.v. fluid loading with normal saline solution before the initiation of dexmedetomidine administration would affect the frequency of hypotension. MATERIALS AND METHODS: Quality assurance data on consecutively registered children who were sedated with dexmedetomidine for MRI were reviewed. All children received a bolus of 3 µg/kg dexmedetomidine followed by a continuous infusion of 2 mg/ kg/h. A normal saline fluid bolus consisting of 0, 10, or 20 mL/kg was administered to each child within 1 hour before initiation of dexmedetomidine administration. Hypotension was defined as a greater than 20% decrease in mean arterial blood pressure from baseline. RESULTS: Sedation was administered to 1692 children. Data on fluid administration were missing in three cases. In the other cases, 252 (14.9%) children received 0 mL/kg of normal saline solution, 598 (35.3%) received 10 mL/kg, and 839 (49.6%) received 20 mL/kg. In a multiple logistic regression model controlled for confounding variables, the odds of development of hypotension with 10 mL/kg of fluid decreased 53% (odds ratio, 0.47; 95% CI, 0.28-0.79; p = 0.004) compared with 0 mL/kg. CONCLUSION: Administration of 10 mL/kg of normal saline solution before the initiation of dexmedetomidine administration for pediatric MRI sedation is effective in decreasing the incidence of observed hypotension.

Effects of fresh gas flow, tidal volume, and charcoal filters on the washout of sevoflurane from the Datex Ohmeda (GE) Aisys, Aestiva/5, and Excel 210 SE Anesthesia Workstations.

PURPOSE: We investigated the effects of tidal volume (VT), fresh gas flow (FGF), and a charcoal filter in the inspiratory limb on the washout of sevoflurane from the following Datex Ohmeda (GE) Anesthesia Workstations (AWSs): Aisys, Aestiva/5, and Excel 210SE. METHODS: After equilibrating the AWSs with 2% sevoflurane, the anesthetic was discontinued, and the absorbent anesthesia breathing circuit (ABC), reservoir bag, and test lung were changed. The lung was ventilated with 350 or 200 mL·breath(-1), 15 breaths·min(-1), and a FGF of 10 L·min(-1) while the washout of sevoflurane was performed in triplicate using a calibrated Datex Ohmeda Capnomac Ultima™ and a calibrated MIRAN SapphIRe XL ambient air analyzer until the concentration was ≤ 10 parts per million (ppm). The effects of decreasing the FGF to 5 and 2 L·min(-1) after the initial washout and of a charcoal filter in the ABC were recorded separately. RESULTS: The median washout times with the Aisys AWS (14 min, P < 0.01) and the Aestiva/5 (17 min, P < 0.001) with VT 350 mL·breath(-1) were significantly less than that with the Excel 210SE (32 min). The mean (95% confidence interval) washout time with the Aisys increased to 23.5 (21.5 to 25.5) min with VT 200 mL·breath(-1) (P < 0.01). Decreasing the FGF from 10 to 5 and 2 L·min(-1) with the Aisys caused a rebound in sevoflurane concentration to ≥ 50 ppm. Placement of a charcoal filter in the inspiratory limb reduced the sevoflurane concentration to < 2 ppm in the Aisys and Aestiva/5 AWSs within two minutes. CONCLUSION: The GE AWSs should be purged with large FGFs and VTs ~350 mL·breath(-1) for ~25 min to achieve 10 ppm sevoflurane. The FGF should be maintained to avoid a rebound in anesthetic concentration. Charcoal filters rapidly decrease the anesthetic concentration to < 2 ppm.