Luck, an Inquisitive Mind, and Opportunities: Lessons Learned: A Blinded Study of Pulse Oximetry before It Became a Standard of Care.

A Single-blind Study of Pulse Oximetry in Children. By CJ Coté, EA Goldstein, MA Cote, DC Hoaglin, and JF Ryan. Anesthesiology 1988; 68:184-8. Reprinted with permission. Oxygen saturation determined by pulse oximetry was monitored in 152 pediatric surgical patients divided into two groups. In one group, the oximeter data and alarms were available (N = 76) to the anesthesia team, and, in the other group, these data were unavailable (N = 76). A trained observer recorded all intraoperative hypoxic episodes and informed the anesthesia team of all major events (i.e., oxygen saturation 85% or less for 30 s or more; Pao2, approximately 52 mmHg). Thirty-five major events occurred: 24 in the unavailable group, and 11 in the available group (P = 0.021). A greater number of major events occurred in children 2 yr or younger (P = 0.013). Hypoxic events diagnosed by the oximeter, but not by the anesthesiologist, were more frequent in the unavailable group (13) than in the available group (5; P = 0.0495). American Society of Anesthesiologists (Schaumburg, Illinois) Physical Status III and IV patients were more likely to suffer a major event (P = 0.009 available, 0.006 unavailable). The pulse oximeter diagnosed hypoxemia before the signs and symptoms of hypoxemia were apparent (i.e., before observed cyanosis or bradycardia). Major hypoxic events were unrelated to duration of anesthesia. Major events were evenly distributed among induction, maintenance, and awakening from anesthesia; a greater number of hypoxic events occurred during induction in the unavailable group (P = 0.031). No morbidity was documented in any patient who suffered a hypoxic event. More patients experienced borderline oxygenation in room air at the end of anesthesia (90% saturation or less) in the unavailable group (12 of 60) than in the available group (3 of 57; P = 0.009). The authors conclude that pulse oximetry, in contrast to changes in vital signs, does provide an early warning of developing hypoxemia in anesthetized children.

Anatomical In Vitro Investigations of the Pediatric Larynx: A Call for Manufacturer Redesign of Tracheal Tube Cuff Location and Perhaps a Call to Reconsider the Use of Uncuffed Tracheal Tubes.

BACKGROUND: Some in vivo studies question the traditional "funnel-shaped" infant larynx; further anatomic examinations were warranted. Examination of fixative free fresh autopsy laryngeal and upper tracheal specimens and multiple measurements was needed to determine consistency between current tracheal tube designs and anatomic observations. METHODS: Larynges from 19 males and 11 females (Caucasian term newborn to 126 months) were examined by the same forensic pathologist. Measurements included anterior/posterior (A/P) and transverse (T) diameters of the cricoid outlet (CO), interarytenoid diameter (IAD), cricothyroid membrane (CTM), distance from the vocal cords (VC) to CO (VC-CO), and calibration of the larynx lumen with uncuffed tracheal tubes as measuring rods. Assessment of "safe tracheal tube placement" was assessed using manufacturer recommended cuffed Microcuff (Kimberly-Clark, Koblenz, Germany) tubes. RESULTS: In 77% (95% confidence interval [CI], 58-90) of specimens, the proximal end of the cuff was within the CO and in 23% even with or close to the CO. The VC-CO varied from 9.1 to 13.17 mm in infants, 11.55 to 15.17 mm in toddlers, and 13.19 to 18.34 mm in children. The A-P/T ratio of the CO was nearly 0.99 in most larynges; the IAD was greater than CO in all specimens. The CTM could be minimally distended in all specimens. CONCLUSIONS: First, despite being marketed as a safer tracheal tube design, the proximal end of the Microcuff cuff rested within or close to the cricoid cartilage theoretically increasing potential cuff-induced injury when using the VC markings for positioning. Our data suggest that the optimal cuff free distance (VC-CO) would be ~13.5 mm for a Microcuff internal diameter (ID) size 3.0, ~15 mm for size 3.5, and ~16 to 19 mm for greater sizes.Second, the CO was virtually circular in all specimens, suggesting that appropriately sized uncuffed tubes should provide an adequate seal in most neonates and toddlers, thus avoiding the potential for cuff-related necrosis injury.Third, the IAD was always greater than CO confirming that the narrowest point of the infant larynx is the nondistensible cricoid cartilage and not the easily distended glottis.Fourth, appropriately sized Microcuff tubes with the cuff deflated completely filled the lumen of the CO and proximal trachea in all specimens. Our data suggest the need for all manufacturers to further evaluate tracheal tube cuff locations and lengths in relation to the VC safe insertion markings, particularly for neonates and toddlers.Fifth, the CTM is minimally distensible, thus having important implications for emergency surgical airway access with most currently available emergency airway devices.

The Society for Pediatric Anesthesia recommendations for the use of opioids in children during the perioperative period.

Opioids have long held a prominent role in the management of perioperative pain in adults and children. Published reports concerning the appropriate, and inappropriate, use of these medications in pediatric patients have appeared in various publications over the last 50 years. For this document, the Society for Pediatric Anesthesia appointed a taskforce to evaluate the available literature and formulate recommendations with respect to the most salient aspects of perioperative opioid administration in children. The recommendations are graded based on the strength of the available evidence, with consensus of the experts applied for those issues where evidence is not available. The goal of the recommendations was to address the most important issues concerning opioid administration to children after surgery, including appropriate assessment of pain, monitoring of patients on opioid therapy, opioid dosing considerations, side effects of opioid treatment, strategies for opioid delivery, and assessment of analgesic efficacy. Regular updates are planned with a re-release of guidelines every 2 years.

The anatomy of the pediatric airway: Has our knowledge changed in 120 years? A review of historic and recent investigations of the anatomy of the pediatric larynx.

BACKGROUND: There is disagreement regarding the anatomy of the pediatric airway, particularly regarding the shape of the cricoid cartilage and the location of the narrowest portion of the larynx. AIMS: The aim of this review is to clarify the origin and the science behind these differing views. METHODS: We undertook a review of published literature, University Libraries, and authoritative textbooks with key search words and phrases. RESULTS: In vivo observations suggest that the narrowest portion of the airway is more proximal than the cricoid cartilage. However, in vitro studies of autopsy specimens measured with rods or calipers, confirm that the nondistensible and circular or near circular cricoid outlet is the narrowest level. These anatomic studies confirmed the classic "funnel" shape of the pediatric larynx. In vivo studies are potentially misleading as the aryepiglottic, vestibular, and true vocal folds are in constant motion with respiration. These studies also do not consider the effects of normal sleep, inhalation agents, and comorbidities such as adenoid or tonsil hypertrophy that cause some degree of pharyngeal collapse and alter the normal movement of the laryngeal tissues. Thus, the radiologic studies suggesting that the narrowest portion of the airway is not the cricoid cartilage may be the result of an artifact depending upon which phase of respiration was imaged. CONCLUSION: In vivo studies do not take into account the motion of the highly pliable laryngeal upper airway structures (aryepiglottic, vestibular, and vocal folds). Maximal abduction of these structures with tracheal tubes or bronchoscopes always demonstrates a larger opening of the glottis compared to the outlet of the cricoid ring. Injury to the larynx depends upon ease of tracheal tube or endoscope passage past the cricoid cartilage and not passage through the readily distensible more proximal structures. The infant larynx is funnel shaped with the narrowest portion the circular or near circular cricoid cartilage confirmed by multiple in vitro autopsy specimens carried out over the past century.

Continuous noninvasive cardiac output in children: is this the next generation of operating room monitors? Initial experience in 402 pediatric patients.

BACKGROUND: Electrical Cardiometry(™) (EC) estimates cardiac parameters by measuring changes in thoracic electrical bioimpedance during the cardiac cycle. The ICON(®), using four electrocardiogram electrodes (EKG), estimates the maximum rate of change of impedance to peak aortic blood acceleration (based on the premise that red blood cells change from random orientation during diastole (high impedance) to an aligned state during systole (low impedance)). OBJECTIVE: To determine whether continuous cardiac output (CO) data provide additional information to current anesthesia monitors that is useful to practitioners. METHODS: After IRB approval and verbal consent, 402 children were enrolled. Data were uploaded to our anesthesia record at one-minute intervals. Ten-second measurements (averaged over the previous 20 heart beats) were downloaded to separate files for later comparison with routine OR monitors. RESULTS: Data from 374 were in the final cohort (loss of signal or improper lead placement); 292,012 measurements during 58,049 min of anesthesia were made in these children (1 day to 19 years and 1 to 107 kg). Four events had a ≥25% reduction in cardiac index at least 1 min before a clinically important change in other monitored parameters; 18 events in 14 children confirmed manifestations of other hemodynamic measures; eight events may have represented artifacts because the observed measurements did not seem to fit the clinical parameters of the other monitors; three other events documented decreased stroke index with extreme tachycardia. CONCLUSIONS: Electrical cardiometry provides real-time cardiovascular information regarding developing hemodynamic events and successfully tracked the rapid response to interventions in children of all sizes. Intervention decisions must be based on the combined data from all monitors and the clinical situation. Our experience suggests that this type of monitor may be an important addition to real-time hemodynamic monitoring.

Anesthesiological considerations for children with obstructive sleep apnea.

PURPOSE OF REVIEW: To summarize recent evidence-based data regarding outcomes associated with children who have obstructive sleep apnea (OSA). RECENT FINDINGS: Internet surveys conducted by pediatric otolaryngologists and pediatric anesthesiologists have reported a disturbing number of deaths within 24 h of tonsillectomy attributed to postsurgical/anesthesia apnea. Several occurred in the post anesthesia care unit after routine monitors had been removed. In addition, a number of deaths also have been attributed to children who have duplicated cytochromes allowing the rapid conversion of codeine to morphine, thus producing a relative drug overdose. Finally, there is some human and animal evidence suggesting that repeated episodes of hypoxemia result in altered opioid receptors causing relative opioid sensitivity. These factors have important clinical implications. SUMMARY: Perioperative deaths in children with OSA occur at a low frequency. Hypoxia-induced opioid sensitivity combined with an approximate 1-2% incidence of rapid conversion of codeine to morphine suggest the need for new approaches for providing preoperative assessment of risk, extended postoperative observation and the need for alternative opioids to codeine. Additionally, new less painful surgical approaches may help to reduce postoperative opioid requirements and therefore perhaps less risk for opiate-induced apnea in this vulnerable population.

Death or neurologic injury after tonsillectomy in children with a focus on obstructive sleep apnea: houston, we have a problem!

BACKGROUND: Obesity is epidemic in the United States and with it comes an increased incidence of obstructive sleep apnea (OSA). Evidence regarding opioid sensitivity as well as recent descriptions of deaths after tonsillectomy prompted a survey of all members of the Society for Pediatric Anesthesia regarding adverse events in children undergoing tonsillectomy. METHODS: An electronic survey was sent to 2377 members of the Society for Pediatric Anesthesia. Additionally, data from the American Society of Anesthesiologists Closed Claims Project were obtained. Adverse events during or after tonsillectomy with or without adenoidectomy in children were included. Children at risk for OSA were identified as either having a positive history for OSA or a post hoc application of the American Society of Anesthesiologists OSA practice guidelines. These children were compared with all other children by Fisher exact test for proportions and t test for continuous variables. RESULTS: A total of 129 cases were identified from the 731 replies to the survey, with 92 meeting inclusion criteria for having adequate data. Another 19 cases with adequate data were identified from the 45 from the American Society of Anesthesiologists Closed Claims Project. A total of 111 cases were included in the final analysis. Death and permanent neurologic injury occurred in 86 (77%) cases and were reported in the operating room, postanesthesia care unit, on the ward, and at home. Sixty-three (57%) children fulfilled American Society of Anesthesiologists criteria to be at risk for OSA. Children categorized as at risk for OSA were more likely than other children to be obese and to have comorbidities (P < 0.0001). A larger proportion of at risk children had the event attributed to apnea (P = 0.016), whereas all others had a larger proportion of events attributed to hemorrhage (P = 0.006). CONCLUSIONS: Deaths or neurologic injury after tonsillectomy due to apparent apnea in children suggest that at least 16 children could have been rescued had respiratory monitoring been continued throughout first- and second-stage recovery, as well as on the ward during the first postoperative night. A validated pediatric-specific risk assessment scoring system is needed to assist with identifying children at risk for OSA who are not appropriate to be cared for on an outpatient basis.

Unintentional epidural injection of 88 µg·kg(-1) of epinephrine.

We report the effects of 88 µg·kg(-1) of epinephrine (1:10,000) injected into the caudal epidural space of a 42-week postconceptual age infant. No long-term neurological or cardiovascular sequelae occurred. Noninvasive cardiac output (CO) monitoring revealed increased CO, contractility, and stroke volume for about an hour, accompanied by a reduction in peripheral vascular resistance and a modest increase in pulse and blood pressure.

A history of pediatric anesthesia: a tale of pioneers and equipment.

The history of pediatric anesthesia is fascinating in terms of how inventive anesthesiologists became over time to address the needs for advances in surgery. We have many pioneers and heroes. We hope you will enjoy this brief overview and that we have not left out any of the early contributors to our speciality. Obviously there is insufficient space to include everyone.

Population pharmacokinetics of intravenous ondansetron in oncology and surgical patients aged 1-48 months.

PURPOSE: Until recently, ondansetron was approved for the prevention of nausea and vomiting only in patients older than 2 years. However, as the use of ondansetron in patients younger than 2 years had been documented, characterization of ondansetron pharmacokinetics in this younger pediatric age group was warranted. METHODS: The pharmacokinetics of intravenously administered ondansetron were evaluated in oncology and surgical patients aged 1-48 months. Pooled data from 124 patients, including 745 pharmacokinetic samples, were analyzed using nonlinear mixed-effects modeling. RESULTS: Ondansetron pharmacokinetics were described by a two-compartment model. Body-size effects on ondansetron disposition were accounted for via standard allometric relationships, normalized to 10.4 kg. A maturation process with a half-life of approximately 4 months was incorporated to describe a decrease in clearance (CL) in infants. Clearance [95% confidence interval (CI)] for a typical patient was 1.53 (1.34-1.78) L/h/kg(0.75) with an interindividual variability of 56.8%. Ondansetron CL was reduced by 31%, 53%, and 76% for the typical 6-month-, 3-month-, and 1-month-old patient, respectively. Simulations showed that an ondansetron dose of 0.1 mg/kg in children younger than 6 months produced exposure similar to a 0.15-mg/kg dose in older children. CONCLUSIONS: The population pharmacokinetic analysis of ondansetron allows for characterization of individual patients based on body weight and age. It is recommended that patients younger than 4 months receiving ondansetron be closely monitored.

Ketamine and neurotoxicity: clinical perspectives and implications for emergency medicine.

Rodent and monkey research has shown that ketamine can induce accelerated programmed nerve cell death (apoptosis) when administered in high doses, for prolonged periods, or both. Concern about similar neurotoxicity with human therapeutic use has prompted ongoing investigations by the Food and Drug Administration and National Institutes of Health. If the results of these inquiries are unfavorable to ketamine, such action could ultimately lead to restricted availability of this drug or even its discontinuation from the market. This article discusses the limitations of the published animal research, the challenges in extrapolating such data to humans, the need for further animal and human investigations, and the potential adverse effect on current clinical practice that might result, should the use of ketamine be restricted or the drug removed from the market.

Pediatric transtracheal and cricothyrotomy airway devices for emergency use: which are appropriate for infants and children?

Cricothyrotomy or insertion of a transtracheal device is a life-saving maneuver that may be performed on an emergent or semi-elective basis as a means of bypassing an obstructed upper airway. A surgeon is trained to perform this life-saving procedure whereas most anesthesiologists are not facile with the scalpel. It is for this reason that many percutaneous devices have been developed for use by surgeons and nonsurgeons alike. Unfortunately, the majority of such devices are designed for use in adults and/or teenagers but are not appropriate for neonates and infants. The unique anatomy of the infant larynx, the small size of the cricothyroid membrane, and the technical difficulty of locating the correct anatomical structures make the use of most of these devices impractical if not outright dangerous in neonates and infants. This paper will review many (but not all) of the available devices, associated literature, pitfalls and dangers. It is emphasized that each clinician should become familiar with the advantages and disadvantages of these devices and obtain training with simulators or animal models. A strategy for management of the 'cannot ventilate, cannot oxygenate, cannot intubate' situation should be developed with age and size appropriate equipment.

Inhalation burn injury in children.

With advances in burn care, many children are surviving severe burn injuries. Inhalation injury remains a predictor of morbidity and mortality in burn injury. Inhalation of smoke and toxic gases leads to pulmonary complications, including airway obstruction from bronchial casts, pulmonary edema, decreased pulmonary compliance, and ventilation-perfusion mismatch, as well as systemic toxicity from carbon monoxide poisoning and cyanide toxicity. The diagnosis of inhalation injury is suggested by the history and physical exam and can be confirmed by bronchoscopy. Management consists of supportive measures, pulmonary toilet, treatment of pulmonary infection and ventilatory support as needed. This review details the pathophysiology, diagnosis, and management options for inhalation injury.

Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures.

The safe sedation of children for procedures requires a systematic approach abstract that includes the following: no administration of sedating medication without the safety net of medical/dental supervision, careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications, appropriate fasting for elective procedures and a balance between the depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure, a focused airway examination for large (kissing) tonsils or anatomic airway abnormalities that might increase the potential for airway obstruction, a clear understanding of the medication's pharmacokinetic and pharmacodynamic effects and drug interactions, appropriate training and skills in airwaymanagement to allow rescue of the patient, age- and size-appropriate equipment for airway management and venous access, appropriate medications and reversal agents, sufficient numbers of appropriately trained staff to bothcarry out the procedure and monitor the patient, appropriate physiologic monitoring during and after the procedure, a properly equippedand staffed recovery area, recovery to the presedation level of consciousness before discharge from medical/dental supervision, and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatricproviders updated information and guidance in delivering safe sedation to children.

Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures.

The safe sedation of children for procedures requires a systematic approach abstract that includes the following: no administration of sedating medication without the safety net of medical/dental supervision, careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications, appropriate fasting for elective procedures and a balance between the depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure, a focused airway examination for large (kissing) tonsils or anatomic airway abnormalities that might increase the potential for airway obstruction, a clear understanding of the medication's pharmacokinetic and pharmacodynamic effects and drug interactions, appropriate training and skills in airway management to allow rescue of the patient, age- and size-appropriate equipment for airway management and venous access, appropriate medications and reversal agents, sufficient numbers of appropriately trained staff to both carry out the procedure and monitor the patient, appropriate physiologic monitoring during and after the procedure, a properly equipped and staffed recovery area, recovery to the presedation level of consciousness before discharge from medical/dental supervision, and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatric providers updated information and guidance in delivering safe sedation to children.