[Monitoring oxygen consumption in energy metabolism in pediatric anesthesia: clinical utility]. / Monitorización del consumo metabólico de oxígeno en anestesia pediátrica. Utilidad clínica.

OBJECTIVES: To determine changes in oxygen consumption as a marker of energy metabolism during general inhaled anesthesia in pediatric patients and to identify factors that might influence consumption. MATERIAL AND METHODS: Prospective, observational, double-blind study in children under inhaled anesthesia in spontaneous ventilation. We monitored heart rate electrocardiogram, noninvasive blood pressure, respiratory frequency, carbon dioxide (CO2) end-expiratory pressure, oxygen saturation by pulse oximetry, state entropy, response entropy, esophageal temperature, and (by indirect calorimetry) oxygen consumption and the respiratory quotient. Capillary blood was extracted every 5 minutes to determine lactate concentration. RESULTS: Thirty-six patients (ASA 1-2) between 5 and 11 years old were included. Mean (SD) oxygen consumption was 0.6 (0.12) mL x kg(-1)min(-1) at baseline, 5.3 (03) mL x kg(-1) min(-1) during maintenance of anesthesia, and 8.1 (1.1) mL x kg(-1) min(-1) on awakening. A progressive increase was detected in lactic acid concentration, from a baseline mean of 0.8 (0.1) mmol/L to 2.2 (0.9) mmol/L half an hour later; the change was unrelated to oxygen consumption. After correcting the flow of normal saline solution to 0.9%, a significant increase in oxygen consumption (P < .05) was detected. Factors that were significantly correlated (P < 0.1 and r of +/- 0.95) were temperature (oxygen consumption decreased > 10% for each degree centigrade decrease), inspired oxygen fraction > 0.8; sharp changes in the expired CO2 fraction exceeding 2 standard deviations (+/- 6), use of nitrous oxide in the gas mix (inspired nitrous oxide fraction > 20%), the length of the sampling line, and increased respiratory frequency. A model with 3 factors was constructed to explain the kinetics of oxygen consumption during anesthesia. CONCLUSIONS: Oxygen consumption monitoring may provide an indirect indicator of homeostatic changes during surgery. The ideal system for carrying out such monitoring during anesthesia remains to be found, and the values to guide the anesthesiologist in deciding whether or not to intervene immediately still need to be determined.

Monitorización del consumo metabólico de oxígeno en anestesia pediátrica. Utilidad clínica / Monitoring oxygen consumption in energy metabolism in pediatric anesthesia: clinical utility

OBJETIVOS: Comprobar las modificaciones en el consumometabólico de oxígeno durante la anestesia generalinhalatoria en el paciente pediátrico y determinar losfactores que pudieran influirlo.MATERIAL Y MÉTODOS: Se realizó un estudio observacionalprospectivo y doble ciego en niños anestesiadoscon anestesia inhalatoria en ventilación espontánea. Semonitorizó la frecuencia cardiaca, el ECG, la presiónarterial no invasiva, la frecuencia respiratoria, la fraccióntelespiratoria de CO2, la saturación de O2 por pulsioximetría,así como la entropía de estado y respuesta,temperatura esofágica y, por calorimetría indirecta, consumode oxígeno y el cociente respiratorio. Se realizaronextracciones capilares seriadas para determinar lactatocada 5 minutos.RESULTADOS: Se incluyeron 36 pacientes de entre 5 y11 años, ASA I y II. El consumo de oxígeno medio encondiciones basales fue 0,6 ± 0,12 ml Kg–1 min–1, duranteel mantenimiento de 5,3 ± 0,3 ml Kg–1 min–1 y en el despertarde 8,1 ± 1,1 ml Kg–1 min–1. Tras la primera mediahora se detectó un aumento progresivo de ácido lácticodel valor medio basal (0,8 ± 0,1 mmol/l), hasta 2,2 ± 0,9mmol/l, que no se correspondía con cambios en el consumode oxígeno. Al corregir con la administración desuero salino fisiológico al 0,9% se detectó elevación significativadel consumo de O2 (p < 0,05). Los factores consignificación estadística (p < 0,01) y un índice de correlación(r) superior a ± 0,95 fueron la temperatura (cadagrado de caída produjo un descenso del consumo de O2> 10%), una FiO2 > 0,8; cambios bruscos en la fracciónespirada de CO2 (superiores a 2 derivaciones estándares± 6), la asociación a la mezcla de gases de óxido nitroso(FiN2O > 20%), la longitud de la línea de muestreo y losaumentos de frecuencia respiratoria. Se pudo obtener unmodelo de tres componentes que determinan la cinéticadel consumo de O2 durante anestesia...(AU)

OBJECTIVES: To determine changes in oxygenconsumption as a marker of energy metabolism duringgeneral inhaled anesthesia in pediatric patients and toidentify factors that might influence consumption.MATERIAL AND METHODS: Prospective, observational,double-blind study in children under inhaled anesthesiain spontaneous ventilation. We monitored heart rateelectrocardiogram, noninvasive blood pressure,respiratory frequency, carbon dioxide (CO2) endexpiratorypressure, oxygen saturation by pulseoximetry, state entropy, response entropy, esophagealtemperature, and (by indirect calorimetry) oxygenconsumption and the respiratory quotient. Capillaryblood was extracted every 5 minutes to determine lactateconcentration.RESULTS: Thirty-six patients (ASA 1-2) between 5 and11 years old were included. Mean (SD) oxygenconsumption was 0.6 (0.12) mL·kg-1min-1 at baseline, 5.3(0.3) mL·kg-1min-1 during maintenance of anesthesia, and8.1 (1.1) mL·kg-1min-1 on awakening. A progressiveincrease was detected in lactic acid concentration, froma baseline mean of 0.8 (0.1) mmol/L to 2.2 (0.9) mmol/Lhalf an hour later; the change was unrelated to oxygenconsumption. After correcting the flow of normal salinesolution to 0.9%, a significant increase in oxygen aproximaconsumption(P<.05) was detected. Factors that weresignificantly correlated (P<0.1 and r of ±0.95) weretemperature (oxygen consumption decreased >10% foreach degree centigrade decrease), inspired oxygenfraction >0.8; sharp changes in the expired CO2 fractionexceeding 2 standard deviations (±6), use of nitrousoxide in the gas mix (inspired nitrous oxide fraction>20%), the length of the sampling line, and increasedrespiratory frequency. A model with 3 factors wasconstructed to explain the kinetics of oxygenconsumption during anesthesia...(AU)