End-tidal CO2 and transcutaneous CO2 : Are we ready to replace arterial CO2 in awake children?

INTRODUCTION: Arterial blood gas analysis (ABG) is the gold standard test for carbon dioxide measurement. End-tidal PCO2 (PetCO2 ) and transcutaneous PCO2 (PtcCO2 ) are noninvasive alternative methods. OBJECTIVE: To examine the use of PetCO2 and PtcCO2 as PaCO2 surrogates in awake children. METHODS: A prospective observational study. Consecutive awake children in a stable condition referred to the Sleep Unit of Hospital de Pediatría Dr. J. P. Garrahan with suspected or confirmed sleep-related respiratory disorders requiring ABG were included. PetCO2 and PtcCO2 were recorded simultaneously during arterial puncture. PetCO2 and PtCO2 values were compared with PaCO2 . Correlation coefficient and Bland-Altman analysis were applied. The sample size was calculated considering a mean difference ≤3 mmHg as clinically acceptable. RESULTS: Sixty-eight sample sets were obtained from 67 patients. The median age was 9.11 years (0.23-18.76). During 94.1% of the procedures patients breathed spontaneously, 30% needed multiple punctures and 92% resulted in pain. Median (IQR) PaCO2 (mmHg) was 36.3 (31.45; 40.90), PetCO2 33.0 (29; 39) and PtcCO2 38.8 (32.95; 43.32). Correlation and agreement for PaCO2 /PetCO2 and PaCO2 /PtcCO2 was r = .6 and .9, and media of bias = 2.83 (-9.97; 15.64) and -1.88 (-9.01; 5.24), respectively. Hypercapnia (PaCO2 > 45.0 mmHg) was present in 8/68 (11.8%) samples. Sensitivity, specificity, positive predictive value and negative predictive value to detect hypercapnia with PetCO2 was 38%, 98%, 75%, and 92%, respectively, and with PtcCO2 , 100%, 90%, 57%, and 100%, respectively. CONCLUSION: PtcCO2 showed better agreement with PaCO2 than PetCO2 but because of the wide dispersion of values, neither method can replace the gold standard. Transcutaneous CO2 might be a good screening tool to detect hypercapnia in awake children.

Feasibility of a pediatric long-term Home Ventilation Program in Argentina: 11 years' experience.

BACKGROUND: Pediatric home ventilation (HV) has increased worldwide. A Home Ventilation Program (HVP) was started in the Pulmonary Department of the "Hospital de Pediatría Prof. Dr. J. P. Garrahan," Argentina, in 2007. This is the largest Argentine national pediatric tertiary care referral center. Limited studies on pediatric HV from Latin American countries have been published. OBJECTIVE: This study describes and analyzes the cohort of children admitted to the HVP during an 11 years period. METHODS: Longitudinal study. POPULATION: all patients (pts) admitted to the HVP between 2007 and 2018. We analyzed demographic and clinical variables, sleep study results, ventilation setting, and start manner collected in a prospective data base. RESULTS: A total of 244 pts were admitted. Median age at ventilation start was 9.41 (3.47-14.08) years, 84% of pts had health insurance. The most frequent underlying diseases were neuromuscular disease (43%) and genetic syndromes (23%). Home-hospital distance was 100-500 km in 16% of cases and greater than 500 km in 34%. Seventy percent of pts had sleep studies before ventilation initiation. Ventilation was started in our general pediatric ward in 83.6%. Noninvasive ventilation was used in 86.1%. The actual number of pts still on follow up is 133 of 244 (54.5%), 16.8% dropped out, 16.4% were transitioned to adult care, 5.32% resolved their sleep-disordered breathing, and 5.32% died. CONCLUSIONS: The HVP admitted pts from all the country. Ventilation was started on the basis of clinical and objective sleep measures. This long-term experience underlines the feasibility of a HVP in an emergent country.

Manifestaciones otorrinoloringológicas del síndrome de Prader Willi / Otorhinolaryngologic manifestations of Prader-Willi syndrome / Manifestações otorrinolaringológicas da síndrome de Prader-Willi

El síndrome de Prader-Willi es la causa sindrómica más común de obesidad infantil. Además de la hiperfagia, son característicos la hipotonía, la disfunción hipotalámica y el retraso del desarrollo psicomotor. Esta combinación de signos y síntomas predispone a que estos niños presenten trastornos respiratorios durante el sueño y un mayor riesgo de aspiración de alimentos y asfixia. Describimos las manifestaciones otorrinolaringológicas de este síndrome en la población pediátrica.

Prader-Willi syndrome is the most common syndromic cause of childhood obesity. In addition to hyperphagia, patients suffer from hypotonia, hypothalamic dysfunction and developmental delay. This combination of signs and symptoms predispose these children to sleep-disordered breathing and to an increased risk of food aspiration and asphyxia. We describe otorhinolaryngologic manifestations of this syndrome in the pediatric population.

Síndrome de Prader-Willi é a causa mais comum de sindrômica obesidade infantil. Além hiperfagia, são característicos hipotonia, disfunção hipotalámica e retardo psicomotor. Esta combinação de sinais e sintomas predispõe essas crianças têm distúrbios respiratórios do sono e aumento do risco de aspiração de alimentos e asfixia. Nós descrevemos as manifestações otorrinolaringológicas desta síndrome na população pediátrica.

[Obstructive sleep apneas in symptomatic obese children: polisomnographic confirmation and its association with disturbances in carbohydrate metabolism]. / Síndrome de apnea obstructiva del sueño en niños obesos sintomáticos: confirmación polisomnográfica y su asociación con trastornos del metabolismo hidrocarbonado.

INTRODUCTION: It has been shown that obesity is a risk factor for Obstructive Sleep Apneas (OSA) and that it could be related to insulin resistance (IR). OBJECTIVE: To establish the frequency of OSA in obese children and adolescents with suggestive symptoms of sleep disordered breathing (SDB) by polisomnografic study (PSG) and to clinically characterize the groups with and without OSA, and their association with IR. PATIENTS, MATERIAL AND METHODS: Descriptive, retrospective, cross-sectional study in patients with obesity and symptoms of SDB examined in the Hospital Nacional de Pediatría "Prof. Dr. Juan P. Garrahan" between october/2002 and july/2008 to whom PGS had been done. Anthropometric and oral glucose tolerance test data were obtained and indices of insulin resistance derived from the homeostatic model were calculated. We assessed the presence of OSA defined as apnea-hypopnea Index > or = 1 Student's and Chi Square Tests were used, establishing a level of significance of 0.05. RESULTS: A total of 58 children were studied (59%M), average age 8.8 +/- 3.5 and Score Z-IMC 2.8 +/- 0.7. In 55.2% of cases, OSA was confirmed, independently of the degree of obesity. 56.9% presented IR. The patients were divided in groups according to the presence or not of OSA. There were no significant differences in age nor in Score Z-IMC. The patients with OSA presented greater frequency of tonsil hypertrophy (p= 0.01, OR= 6.86) and IR (p= 0.01, OR= 4,44) and less insulin sensitivity (p= 0.04). CONCLUSIONS: Both IR and the presence of tonsil hypertrophy were predictors of OSA. This population seems to be heterogeneous. We underline the importance to look for SDB related signs and symptoms in patients with obesity of any degree.

Síndrome de apnea obstructiva del sueño en niños obesos sintomáticos: confirmación polisomnográfica y su asociación con trastornos del metabolismo hidrocarbonado / Obstructive sleep apneas in symptomatic obese children: polisomnographic confirmation and its association with disturbances in carbohydrate metabolism

La obesidad es un factor de riesgo para el síndrome de apnea obstructiva del sueño (SAOS) que estaría relacionado a insulinorresistencia(IR).Objetivo. Establecer la frecuencia de SAOS, mediante polisomnografía (PSG) en niños y adolescentes obesos con síntomas sugestivos de trastornos respiratorios del sueño y caracterizar clínicamente los grupos con SAOS y sin él, y su asociación con IR.Población, material y métodos. Estudio descriptivo, retrospectivo, transversal de pacientes obesos atendidos en el Hospital Nacional de Pediatría Prof. Dr. Juan P. Garrahan, entre octubre/2002-julio/2008, con PSG realizada porpresentar síntomas asociados a trastornos respiratorios del sueño (TRS).Se recabaron datos antropométricos, se realizó prueba de tolerancia oral a la glucosa y se calcularon índices de insulinorresistencia (modelo homeostático).Se evaluó la presencia de SAOS definida por Índice de apnea-hipopnea obstructiva/hora ≥ 1.Se aplicaron las pruebas de Student y c2. Se trabajó con un nivel de significación de 0,05.Resultados. Estudiamos 58 niños (60 por ciento V) edad (media) 8,8 años por ciento 3,5 y puntaje Z-IMC 2,8 más menos 0,7.En el 55,2 por ciento se confirmó SAOS, independientemente del grado de obesidad. En el 56,9 por ciento se hallóIR. Agrupamos los pacientes de acuerdo a la presencia o no de SAOS; no encontramos diferencias significativas en edad ni en puntaje ZIMC. Los pacientes con SAOS presentaron mayor frecuencia de hipertrofia amigdalina (p= 0,01;OR= 6,86), IR (p= 0,01; OR= 4,44) y menor sensibilidad a la insulina (p= 0,04).Conclusiones. Tanto la IR como la presencia de hipertrofia amigdalina fueron predictoras de SAOS. La población con SAOS parece ser heterogénea.Remarcamos la importancia de la búsqueda de signos y síntomas relacionados con TRS en los pacientes con obesidad de cualquier grado.

Síndrome de apnea obstructiva del sueño en niños obesos sintomáticos: confirmación polisomnográfica y su asociación con trastornos del metabolismo hidrocarbonado / Obstructive sleep apneas in symptomatic obese children: polisomnographic confirmation and its association with disturbances in carbohydrate metabolism

La obesidad es un factor de riesgo para el síndrome de apnea obstructiva del sueño (SAOS) que estaría relacionado a insulinorresistencia(IR).Objetivo. Establecer la frecuencia de SAOS, mediante polisomnografía (PSG) en niños y adolescentes obesos con síntomas sugestivos de trastornos respiratorios del sueño y caracterizar clínicamente los grupos con SAOS y sin él, y su asociación con IR.Población, material y métodos. Estudio descriptivo, retrospectivo, transversal de pacientes obesos atendidos en el Hospital Nacional de Pediatría Prof. Dr. Juan P. Garrahan, entre octubre/2002-julio/2008, con PSG realizada porpresentar síntomas asociados a trastornos respiratorios del sueño (TRS).Se recabaron datos antropométricos, se realizó prueba de tolerancia oral a la glucosa y se calcularon índices de insulinorresistencia (modelo homeostático).Se evaluó la presencia de SAOS definida por Indice de apnea-hipopnea obstructiva/hora ≥ 1.Se aplicaron las pruebas de Student y c2. Se trabajó con un nivel de significación de 0,05.Resultados. Estudiamos 58 niños (60 por ciento V) edad (media) 8,8 años por ciento 3,5 y puntaje Z-IMC 2,8 más menos 0,7.En el 55,2 por ciento se confirmó SAOS, independientemente del grado de obesidad. En el 56,9 por ciento se hallóIR. Agrupamos los pacientes de acuerdo a la presencia o no de SAOS; no encontramos diferencias significativas en edad ni en puntaje ZIMC. Los pacientes con SAOS presentaron mayor frecuencia de hipertrofia amigdalina (p= 0,01;OR= 6,86), IR (p= 0,01; OR= 4,44) y menor sensibilidad a la insulina (p= 0,04).Conclusiones. Tanto la IR como la presencia de hipertrofia amigdalina fueron predictoras de SAOS. La población con SAOS parece ser heterogénea.Remarcamos la importancia de la búsqueda de signos y síntomas relacionados con TRS en los pacientes con obesidad de cualquier grado.(AU)

Clinical-etiologic correlation in children with Prader-Willi syndrome (PWS): an interdisciplinary study.

Prader-Willi syndrome (PWS) is a multisystemic disorder caused by the loss of expression of paternally transcribed genes within chromosome 15q11-q13. Most cases are due to paternal deletion of this region; the remaining cases result from maternal uniparental disomy (UPD) and imprinting defects. To better understand the phenotypic variability of PWS, a genotype-phenotype correlation study was performed in 91 children with PWS. Patients were diagnosed by Southern Blot Methylation assay and genetic subtypes were established using FISH and microsatellite analyses. Fifty-nine subjects with deletion (31/28 males/females; mean age 3.86 years), 30 with UPD (14/16 males/females; mean age 3.89 years) and 2 girls with a presumed imprinting defect (mean age 0.43 yrs) were identified. For correlation purposes patients were grouped as "deleted" and "non-deleted." An increased maternal age was found in the UPD group. Four of Holm's criteria were more frequently present in the deleted group: need for special feeding techniques, sleep disturbance, hypopigmentation, and speech articulation defects. Concerning cognitive assessments, only 9.52% of subjects with deletion had Full-Scale IQ (FSIQ) > or =70, while 61.53% of subjects without deletion had FSIQ > or =70. Similar results were found in behavioral measures. Sleep disorders and carbohydrate metabolism were systematically assessed. Polysomnoghaphic studies revealed a higher frequency of central events with desaturations > or =10% in the deleted group (P = 0.020). In summary, the phenotype was significantly different between both groups in certain parameters related to the CNS. These results might be related to the differences in brain gene expression of the genetic subtypes.

Relevance of a portable spirometer for detection of small airways obstruction.

While portable spirometers are increasingly used, little attention has been paid to test their validity for measurement of flows in small airways. The aim of this study was to compare the Spirotel portable spirometer to a laboratory spirometer (Jeager PFT), with regard to accuracy in measuring forced expiratory flows, and more specifically those influenced by small airways (FEF(25-75)). Fifty-nine children (mean age, 12 years; range, 7-17), were studied at baseline and after a bronchodilator inhalation. Spirometers were tested separately in a randomly designed order. A total of 117 sessions of flow-volume curves was performed with each spirometer. We obtained at least two acceptable and reproducible curves in 88% and 76% of the sessions, with the laboratory and the portable spirometers, respectively. Unacceptable curves were easily detected by visual inspection of flow-time and flow-volume waveforms. Agreement was excellent between spirometers for the measurement of all expiratory flows, both at baseline and postbronchodilator. More specifically, agreement between spirometers was as high for measurements of FEF(25-75) (intraclass correlation coefficients 0.97) as for proximal flows. High correlations were found between baseline expiratory flows measured by each spirometer (and expressed as percent of predicted values), both in large and small airways (P < 0.001). The portable spirometer was highly sensitive for detecting small airways obstruction, as compared to the laboratory spirometer. Finally, the magnitudes of bronchodilator-related flow changes were also highly correlated, both in large and small airways (P < 0.001 and P = 0.004, respectively). We conclude that the Spirotel portable spirometer is reliable for measurement of forced expiratory flows, in large and small airways, provided that all curve waveforms can be stored and available for visual inspection.

Sleep desaturation: comparison of two oximeters.

Oxygen saturation is measured by pulse oximetry during sleep studies. Body movements and peripheral vasoconstriction related to respiratory events may interfere with measurements by conventional oximeters. Our objective was to compare the detection rate of sleep desaturations by two oximeters, one of which used new motion-resistant technology. We studied 34 children (median age, 13 years; range, 3-18) with suspected sleep-disordered breathing. During polysomnography, oxygen saturation was measured by two oximeters set on fast mode: the motion-resistant Radical oximeter (2-sec averaging), and the conventional Nellcor N-200 oximeter (2-3-sec averaging). Respiratory events were identified based on airflow signal. The numbers of respiratory event-related desaturations > or =3% or > or =5% detected by each oximeter were determined. Valid desaturations were defined using the Nellcor plethysmographic waveform and the Radical signal-quality data. Hypoxemic respiratory events were those with associated valid desaturation. In total, 1,278 respiratory events were identified and pooled. Basal oxygen saturation measured just before event onset was not different between oximeters (Radical: 98%; range, 84-100; Nellcor: 97%; range, 86-100; P = ns). However, the Radical detected a greater number of valid desaturations than did the Nellcor for any level of desaturation (respectively, N = 651 and 476 desaturations > or =3%, P < 0.001; and N = 232 and 146 desaturations > or =5%, P = 0.01). Consequently, for each patient, the number of hypoxemic respiratory events per hour of sleep was greater using the Radical than using the Nellcor (P = 0.002, and P = 0.021, for desaturation > or =3% and > or =5%, respectively). In conclusion, standardized oximeter settings are required to achieve more accurate assessments of hypoxemia in children with sleep-disordered breathing.

Use of nasal cannula for detecting sleep apneas and hypopneas in infants and children.

We evaluated tolerance of nasal cannula (NC) by 14 infants (median age, 2.6 months) and 16 children (median age, 5.5 years) with suspected obstructive sleep apnea syndrome and compared the efficacy of the NC with that of a nasobuccal thermistor in detecting obstructive apneas (OA) and obstructive hypopneas (OH) on polysomnography traces. The relationship between cannula flow and esophageal pressure was assessed in six patients. Time spent with an uninterpretable flow signal was longer when using a cannula than when using a thermistor in infants (p < 0.05) and children (p < 0.01), and it was longer in the younger patients (p < 0.05). Among the 650 OA-OH detected by either method, only 38% were detected by both, and 58% were detected by the cannula and missed by the thermistor, so that the apnea-hypopnea index was higher with cannula than with thermistor in each age group (p < 0.01). More hypopneas than apneas were detected by the cannula and missed by the thermistor (p < 0.001). Out-of-phase thoracic and abdominal motions and/or changes in the end-tidal CO(2) signal shape were associated with 86% of OH identified by cannula. In the six patients whose esophageal pressure was measured, all respiratory events identified using a cannula were associated with increased "airway resistance." Thus, the NC is more likely than the thermistor to detect OA and OH in infants and children, and this superiority is particularly marked for hypopneas.