Capnografía en recién nacidos en ventilación mecánica y su relación con la medición de CO2 en muestras sanguíneas / Capnography in newborns under mechanical ventilation and its relationship with the measurement of CO2 in blood samples

Introducción: Monitorear la presión parcial de CO2 (PCO2) en los recién nacidos que requieren ventilación permitiría evitar hipocapnia e hipercapnia. La medición de CO2 espirada (ETCO2) es una alternativa poco implementada en esta población.Objetivo: Evaluar la relación entre la ETCO2 y la PCO2 en recién nacidos.Métodos: Estudio de corte transversal, comparativo entre dos métodos de medición de PCO2, el convencional mediante análisis de muestras sanguíneas y el estimado mediante ETCO2. Se incluyeron recién nacidos internados que requerían ventilación mecánica convencional. La medición de ETCO2 se realizó mediante un ventilador neonatal Graph Net Neo-TECME®, con capnógrafo incorporado y se obtuvo el gradiente ETCO2-PCO2. Se realizaron análisis de correlación y gráficos de Bland-Altman para estimar la concordancia.Resultados: Se analizaron 277 muestras (ETCO2/PCO2) en 83 recién nacidos. Los valores promedios de ETCO2 y PCO2 fueron de 41,36 mmHg y 42,04 mmHg. Hubo correlación positiva y significativa entre ETCO2 y PCO2 en el análisis global (r = 0,5402; p < 0,001) y en el de cada unidad (p < 0,001). La media de las diferencias fue de 0,68 mmHg (IC 95%- 0,68 a 1,95) y no resultó significativa. Se observó error sistemático positivo (PCO2 > ETCO2) en dos de las unidades, mientras que en la tercera la diferencia fue negativa (PCO2 < ETCO2)Discusión: La correlación entre ETCO y PCO2 es significativa, si bien los valores obtenidos no resultan equivalentes y la diferencia varía entre 0,1 mmHg a 20 mmHg. Asimismo, observamos errores sistemáticos de signo diferente (positivo o negativo) entre las instituciones. (AU)

Introduction: Monitoring the partial pressure of CO2 (PCO2) in newborns who require ventilation would allow avoiding hypocapnia and hypercapnia. The measurement of end-tidal carbon dioxide (ETCO2) is an alternative rarely implemented in this population.Objective: To evaluate the relationship between ETCO2 and PCO2 in newborns.Methods: Cross-sectional study comparing two PCO2 measurement methods, the conventional one by analysis of blood samples and the one estimated by ETCO2. The study included hospitalized newborns that required conventional mechanical ventilation. The ETCO2 was measured with a Tecme GraphNet® neo, a neonatal ventilator with an integrated capnography, and we obtained the ETCO2-PCO2 gradient. We conducted correlation and Bland-Altman plot analyses to estimate the agreement.Results: A total of 277 samples (ETCO2/PCO2) from 83 newborns were analyzed. The mean values of ETCO2 and PCO2 were 41.36 mmHg and 42.04 mmHg. There was a positive and significant correlation between ETCO2 and PCO2 in the overall analysis (r = 0.5402; p < .001) and in the analysis of each unit (p < .001). The mean difference was 0.68 mmHg (95% CI, −0.68 to 1.95) and was not significant. We observed a positive systematic error (PCO2 > ETCO2) in 2 of the units, and a negative difference in the third (PCO2 < ETCO2).Discussion: The correlation between ETCO and PCO2 was significant, although the obtained values were not equivalent, with differences ranging from 0.1 mmHg to 20 mmHg. Likewise, we found systematic errors that differed in sign (positive or negative) between institutions. (AU)

Capnography in newborns under mechanical ventilation and its relationship with the measurement of CO2 in blood samples.

INTRODUCTION: Monitoring the partial pressure of CO2 (PCO2) in newborns who require ventilation would allow avoiding hypocapnia and hypercapnia. The measurement of end-tidal carbon dioxide (ETCO2) is an alternative rarely implemented in this population. OBJECTIVE: To evaluate the relationship between ETCO2 and PCO2 in newborns. METHODS: Cross-sectional study comparing two PCO2 measurement methods, the conventional one by analysis of blood samples and the one estimated by ETCO2. The study included hospitalized newborns that required conventional mechanical ventilation. The ETCO2 was measured with a Tecme GraphNet® neo, a neonatal ventilator with an integrated capnograph, and we obtained the ETCO2-PCO2 gradient. We conducted correlation and Bland-Altman plot analyses to estimate the agreement. RESULTS: A total of 277 samples (ETCO2 / PCO2) from 83 newborns were analyzed. The mean values ​​of ETCO2 and PCO2 were 41.36mmHg and 42.04mmHg. There was a positive and significant correlation between ETCO2 and PCO2 in the overall analysis (r=0.5402; P<.001) and in the analysis of each unit (P<.001). The mean difference was 0.68 mmHg (95% CI, -0.68 to 1.95) and was not significant. We observed a positive systematic error (PCO2 > ETCO2) in 2 of the units, and a negative difference in the third (PCO2 < ETCO2). DISCUSSION: The correlation between ETCO and PCO2 was significant, although the obtained values ​​were not equivalent, with differences ranging from 0.1mmHg and 20mmHg. Likewise, we found systematic errors that differed in sign (positive or negative) between institutions.

Open lung strategy in a lamb model of respiratory distress syndrome.

We tested the hypothesis that an open lung strategy with recruitment maneuvers will improve oxygenation and decrease lung injury in comparison with a permissive hypercapnia strategy in preterm lambs. Preterm lambs born by operative delivery at 131 ± 1 days of gestational age (term = 150 days) were randomized to an open lung group (OLG, n = 5) or a permissive hypercapnia group (PHG, n = 4). In the OLG, ramp recruitment maneuvers were performed by increasing and then decreasing peak inspiratory pressure and positive end-expiratory pressure (adjusting for expiratory tidal volume [V(T)] 6 to 8 mL/kg). In the PHG, lambs received ventilation with V(T) of 6 to 8 mL/kg, adapting pressures and respiratory rate according to arterial blood gases results. Fraction of inspired oxygen was adjusted for oxygen saturation 88 to 93%. Lambs were ventilated for 6 hours. Lung pathology was assessed by masked examiners. There were no significant differences for arterial to alveolar oxygen tension ratio, partial pressure of arterial carbon dioxide, blood pressure, compliance, resistance, and other variables between groups. Gas leaks were noted in four of five lambs in the OLG and one of four in the PHG (relative risk 3.2; 95% confidence interval 0.5 to 18). By histological examination, lung areas were overdistended (49% in the OLG, 37% in the PHG). Open lung ventilation following ramp recruitment maneuvers did not offer advantages and might increase lung injury compared with a permissive hypercapnia strategy in preterm lambs with lung immaturity.