Pediatric anesthesiology in Brazil, Chile, and Mexico.

BACKGROUND: Latin America comprises an extensive and diverse territory composed of 33 countries in the Caribbean, Central, and South America where Romance languages-languages derived from Latin are predominantly spoken. Economic disparities exist, with inequitable access to pediatric surgical care. The Latin American Surgical Outcomes Study in Pediatrics (LASOS-Peds), a multi-national collaboration, will determine safety of pediatric anesthesia and perioperative care. OBJECTIVE: Below, we provide a descriptive initiative to share how pediatric anesthesia in Brazil, Chile, and Mexico operate. Theses descriptions do not represent all of Latin America. DESCRIPTIONS AND CONCLUSIONS: Brazil an upper middle-income country, population 203 million, has a public system insufficiently resourced and a private system, resulting in inequitable safety and accessibility. Surgical complications constitute the third leading cause of mortality. Anesthesiology residency is 3 years, with required rotations in pediatric anesthesia; five hospitals offer pediatric anesthesia fellowships. Anesthesiology is a physician-only practice. A Pediatric Anesthesia Committee within the Brazilian Society of Anesthesiology offers education through seasonal courses and workshops including pediatric advanced life support. Chile is a high-income country, population 19.5 million, the majority cared for in the public system, the remainder in university, private, or military systems. Government efforts have gradually corrected the long-standing anesthesiology shortage: twenty 3-year residency programs prepare graduates for routine pediatric cases. The Chilean Society of Anesthesiology runs a 1-month program for general anesthesiologists to enhance pediatric anesthesia skills. Pediatric anesthesia fellowship training occurs in Europe, USA, and Australia, or in two 2-year Chilean university programs. Public health policies have increased the medical and surgical pediatric specialists and general anesthesiologists, but not pediatric anesthesiologists, which creates safety concerns for neonates, infants, and medically complex. Chile needs more pediatric anesthesia fellowship programs. Mexico, an upper middle-income country, with a population of about 126 million, has a five-sector healthcare system: public, social security for union workers, state for public employees, armed forces for the military, and a private "self-pay." There are inequities in safety and accessibility for children. Pediatric Anesthesiology fellowship is 2 years, after 3 years residency. A shortage of pediatric anesthesiologists limits accessibility and safety for surgical care, driven by added training at low salary and hospital under appreciation. The Mexican Society of Pediatric Anesthesiology conducts refresher courses, workshops, and case conferences. Insufficient resources and culture limits research.

Exhaled nitric oxide measurement before pediatric adenotonsillectomy: A feasibility study.

BACKGROUND: Exhaled nitric oxide (eNO) is a known biomarker for the diagnosis and monitoring of bronchial hyperreactivity in adults and children. AIMS: To investigate the potential role of eNO measurement for predicting perioperative respiratory adverse events in children, we sought to determine its feasibility and acceptability before adenotonsillectomy. METHODS: We attempted eNO testing in children, 4-12 years of age, immediately prior to admission for outpatient adenotonsillectomy. We used correlations between eNO levels and postoperative adverse respiratory events to make sample size predictions for future studies that address the predictability of the device. RESULTS: One hundred and three (53%) of 192 children were able to provide an eNO sample. The success rate increased with age from 23% (9%-38%) at age 4 to over 85% (54%-98%) after age 9. Using the eNO normal value (<20 ppb) as a cutoff, an expected sample size to detect a significant difference between children with and without adverse events is 868, assuming that respiratory adverse events occur in 29% of children. CONCLUSIONS: eNO testing on the day of surgery has limited feasibility in children younger than 7 years of age. The most common reason for failure was inadequate physical performance while interacting with the testing device. The role of this respiratory biomarker in the context of perioperative outcomes for pediatric adenotonsillectomy remains unknown and should be further studied with improved technologies.

Secondhand Smoke exposure and risk of Obstructive Sleep Apnea in Children.

OBJECTIVES: Obstructive sleep apnea (OSA) has a prevalence of 4% in children. Few studies have explored the role of secondhand smoke (SHS) on OSA severity and have shown contradicting results. Most studies have focused on the effect of SHS on snoring. This study explored the association of SHS exposure and OSA severity in children aged 3-18 years. METHODS: This is a retrospective single center IRB-approved study. Electronic Medical Records (EMR) were queried between 1/24/2015 and 1/24/2018 to obtain data on SHS exposure with standard questionnaires from perioperative database. SHS was analyzed as a binary variable and OSA was measured using obstructive apnea hypopnea index (OAHI) from polysomnography (PSG) as a continuous variable. Analyses were done on all children and in those with severe OSA (OAHI≥10/h) as a subgroup. RESULTS: EMR query yielded 101,884 children of whom 3776 had PSG. Limiting baseline PSG in 3-18-year-old and reliable information on SHS yielded 167 analyzable children of whom 70 had severe OSA. Children exposed to SHS had significantly more public insurance than non-exposed (p < 0.0001). Among children with severe OSA, median OAHI was significantly higher in SHS exposed compared to non-exposed (29.0vs.19.5,p = 0.04), but not across all children. In multivariable analysis SHS exposure increased OAHI by 48% in severe OSA subgroup (95%CI: 8%-102%; p = 0.01) when adjusted for race, body mass index, and adjusted household income. CONCLUSION: Children aged 3-18 years with severe OSA who were exposed to SHS were found to have 1.48 increase in odds of OAHI than those without SHS exposure. Results could be limited by retrospective nature of study and EMR tools.

STBUR: Sleep trouble breathing and unrefreshed questionnaire: Evaluation of screening tool for postanesthesia care and disposition.

BACKGROUND: The Snoring, Trouble Breathing, and Un-Refreshed (STBUR) questionnaire is a five-question screening tool for pediatric sleep-disordered breathing and risk for perioperative respiratory adverse events in children. The utility of this questionnaire as a preoperative risk-stratification tool has not been investigated. In view of limited availability of screening tools for preoperative pediatric sleep-disordered breathing, we evaluated the questionnaire's performance for postanesthesia adverse events that can impact postanesthesia care and disposition. METHODS: The retrospective study protocol was approved by the institutional research board. The data were analyzed using two different definitions for a positive screening based on a five-point scale: low threshold (scores 1 to 5) and high threshold (score of 5). The primary outcome was based on the following criteria: (a) supplemental oxygen therapy following postanesthesia care unit (PACU) stay until hospital discharge, (b) greater than two hours during phase 1 recovery, (c) anesthesia emergency activation in the PACU, and (d) unplanned hospital admission. RESULTS: About 6025 patients completed the questionnaire during the preoperative evaluation. And 1522 patients had a low threshold score and 270 had a high-threshold score. We found statistically significant associations in three outcomes based on the low threshold score: supplemental oxygen therapy (negative-predictive value [NPV] 0.97, 95% CI 0.97-98), PACU recovery time (NPV 0.99, 95% CI 0.99-0.99) and escalation of care (NPV 0.98, 95% CI 0.97-0.98). Positive-predictive values were statistically significant for all outcomes except anesthesia emergency in the PACU. CONCLUSION: The Snoring, Trouble Breathing, and Un-Refreshed questionnaire identified patients at higher risk for prolonged phase 1 recovery, oxygen therapy requirement, and escalation of care. The questionnaire's high-negative predictive value and specificity may make it useful as a screening tool to identify patients at low risk for prolonged stay in PACU.

Comparing the effect of arginine vasopressin on ear and finger photoplethysmography.

STUDY OBJECTIVE: To test whether the relative insensitivity of craniofacial vessels to catecholamines differs in response to arginine vasopressin. DESIGN: Prospective, observational human study. SETTING: University hospital. PATIENTS: 8 ASA physical status I and II women scheduled for elective myomectomy. INTERVENTIONS: Patients underwent elective myomectomy surgery with intrauterine injection of arginine vasopressin. MEASUREMENTS: Finger, ear, and forehead photoplethysmographs were monitored. Changes in the plethysmographic amplitudes were recorded before and after arginine vasopressin injection. MAIN RESULTS: In all subjects, ear photoplethysmographic amplitude (but not oxygen saturation) decreased precipitously (62% +/- 10%; P < 0.001) after arginine vasopressin injection. In contrast, there was no significant decline in the finger signal (4.5% +/- 27%; P = 0.19). The forehead plethysmograph decreased in amplitude, but this finding did not achieve significance (33% +/- 18%; P = 0.18). CONCLUSION: In contrast to prior observations during adrenergic activation, arginine vasopressin induced relatively greater vasoconstriction at the ear and forehead than at the finger. This finding has potential implications with respect to arginine vasopressin's effect on blood flow and indicates that monitoring the ear plethysmographic signal may provide useful information during arginine vasopressin administration.

Impact of withdrawal of 450 ml of blood on respiration-induced oscillations of the ear plethysmographic waveform.

OBJECTIVE: It has been widely appreciated that ventilation-induced variations in systolic blood pressure during mechanical ventilation correlate with changes in intravascular volume. The present study assessed whether alterations in volume status likewise can be detected with noninvasive monitoring (ear plethysmograph) in non-intubated subjects (awake volunteers). METHODS: Eight healthy adults were monitored with EKG, noninvasive blood pressure, an unfiltered ear plethysmograph, and a respiratory force transduction belt before (PRE) and after (POST) withdrawal of 450 ml of blood from an antecubital vein. Spectral-domain analysis was used to determine the peak ventilatory frequency and the power of the associated variation in the ear plethysmographic tracing; Interphase differences in the respiration-induced plethysmographic variations were assessed by Wilcoxon signed rank test. In addition, the changes in the ear plethysmographic tracing were compared to changes in heart rate and blood pressure. RESULTS: There was a significant increase in respiratory-associated oscillations at the respiratory frequency between the PRE and POST phases (p = 0.012). These changes were detected despite lack of changes in heart rate or blood pressure. CONCLUSIONS: Respiration-induced changes of the ear plethysmographic waveform during spontaneous ventilation increase significantly as a consequence of withdrawal of approximately one unit of blood in healthy volunteers.

What is the best site for measuring the effect of ventilation on the pulse oximeter waveform?

The cardiac pulse is the predominant feature of the pulse oximeter (plethysmographic) waveform. Less obvious is the effect of ventilation on the waveform. There have been efforts to measure the effect of ventilation on the waveform to determine respiratory rate, tidal volume, and blood volume. We measured the relative strength of the effect of ventilation on the reflective plethysmographic waveform at three different sites: the finger, ear, and forehead. The plethysmographic waveforms from 18 patients undergoing positive pressure ventilation during surgery and 10 patients spontaneously breathing during renal dialysis were collected. The respiratory signal was isolated from the waveform using spectral analysis. It was found that the respiratory signal in the pulse oximeter waveform was more than 10 times stronger in the region of the head when compared with the finger. This was true with both controlled positive pressure ventilation and spontaneous breathing. A significant correlation was demonstrated between the estimated blood loss from surgical procedures and the impact of ventilation on ear plethysmographic data (r(s) = 0.624, P = 0.006).

Opioids in pediatric anesthesia.

Opioids are used widely in the practice of pediatric anesthesia and pediatric perioperative medicine. The benefits of opioids are well documented, and their pharmacology has been extensively studied. Nonetheless special care is important when using these agents in the pediatric population. This article addresses the developmental pharmacologic changes that occur with opioids as well as their most common clinical uses.