RESUMEN
BACKGROUND: Critically ill patients are characterized by a hypermetabolic state, a catabolic response, higher nutritional needs, and a decreased capacity for utilization of parenteral substrate. OBJECTIVE: We sought to analyze the relation between a patient's metabolic state and their nutritional intake, substrate utilization, and nitrogen balance (NB) in mechanically ventilated, critically ill children receiving parenteral nutrition. DESIGN: This was a cross-sectional study in which resting energy expenditure (REE) and NB were measured and substrate utilization and the metabolic index (MI) ratio (REE/expected energy requirements) were calculated. RESULTS: Thirty-three children (mean age: 5 y) participated. Their average REE was 0.23 +/- 0.10 MJ x kg(-1) x d(-1) and their average MI was 1.2 +/- 0.5. Mean energy intake, protein intake, and NB were 0.25 +/- 0.14 MJ x kg(-1) x d(-1), 2.1 +/- 1 g x kg(-1) x d(-1), and -89 +/- 166 mg x kg(-1) x d(-1), respectively. Patients with an MI >1.1 (n = 19) had a higher fat oxidation than did patients with an MI <1.1 (n = 14; P < 0.05). Patients with lipogenesis (n = 13) had a higher carbohydrate intake than did patients without lipogenesis (n = 20; P < 0.05). Patients with a positive NB (n = 12) had a higher protein intake than did patients with a negative NB (n = 21; P < 0.001) and lower protein oxidation (P < 0.01). CONCLUSIONS: Critically ill children are hypermetabolic and in negative NB. In this population, fat is used preferentially for oxidation and carbohydrate is utilized poorly. A high carbohydrate intake was associated with lipogenesis and less fat oxidation, a negative NB was associated with high oxidation rates for protein, and a high protein intake was associated with a positive NB.
Asunto(s)
Enfermedad Crítica , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/metabolismo , Proteínas en la Dieta/metabolismo , Metabolismo Energético , Nitrógeno/metabolismo , Adolescente , Metabolismo Basal , Calorimetría Indirecta , Niño , Preescolar , Estudios Transversales , Carbohidratos de la Dieta/administración & dosificación , Grasas de la Dieta/administración & dosificación , Proteínas en la Dieta/administración & dosificación , Femenino , Humanos , Lactante , Masculino , Necesidades Nutricionales , Nutrición Parenteral , Respiración Artificial , Especificidad por SustratoRESUMEN
Respiratory syncytial virus (RSV) is an important respiratory pathogen for infants. Aerosolized ribavirin (AR) has been used in mechanically ventilated (MV) patients with RSV bronchiolitis. The purpose of this study was to measure respiratory system mechanics (RSM) in pediatric patients requiring MV and receiving AR for suspected RSV. Patients were prospectively randomized to receive AR, either at a regular dose (RD) (6 g/300 mL over 18 hr/day) or a high dose (HD) (6 g/100 mL over 2 hr, three times a day). To measure changes in RSM, a passive exhalation technique was used before and after each dose of AR; time constant (tc) in s, resistance (Rrs) in cmH(2)O/mL/kg/s, and quasistatic compliance (Crs) in mL/cmH(2)O/kg were measured. Airway pressure and flow signals were obtained and analyzed using a pneumotachograph, a differential pressure transducer, and a computer interface. Statistical analysis was done by Mann-Whitney and Wilcoxon rank tests. Thirteen patients were enrolled: 5 patients in the HD group (mean age of 52 months), and 8 patients in the RD group (mean age of 10 months). Four and 5 patients were positive for RSV by ELISA in the HD and RD groups, respectively. The RSM in the HD group were: tc, 0.58 +/- 0.15 s and 0.55 +/- 0.20 s before and after AR, respectively; Rrs, 0.03 +/- 0. 03 cmH(2)0/mL/kg/s and 0.02 +/- 0.02 cmH(2)0/mL/kg/s, respectively; and Crs, 0.63 +/- 0.21 mL/cmH(2)O/kg and 0.70 +/- 0.13 mL/cmH(2)O/kg, respectively. In the RD group, the RSM were: tc, 0.37 +/- 0.12 s and 0.31 +/- 0.10 s before and after AR, respectively; Rrs, 0.03 +/- 0.02 cmH(2)0/mL/kg/s and 0.02 +/- 0.01 cmH(2)0/mL/kg/s, respectively (P < 0.05); and Crs, 0.46 +/- 0.20 mL/cmH(2)O/kg and 0.46 +/- 0.19 mL/cmH(2)O/kg, respectively. We conclude that the use of AR for bronchiolitis in infants and young children during mechanical ventilation does not worsen RSM.
Asunto(s)
Antivirales/administración & dosificación , Bronquiolitis Viral/terapia , Respiración Artificial , Mecánica Respiratoria/efectos de los fármacos , Infecciones por Virus Sincitial Respiratorio/terapia , Ribavirina/administración & dosificación , Administración por Inhalación , Aerosoles , Resistencia de las Vías Respiratorias/efectos de los fármacos , Bronquiolitis Viral/fisiopatología , Preescolar , Humanos , Lactante , Rendimiento Pulmonar/efectos de los fármacos , Estudios Prospectivos , Infecciones por Virus Sincitial Respiratorio/fisiopatologíaRESUMEN
Nutritional support is important in critically ill patients, with variable energy and nitrogen requirements (e.g., sepsis, trauma, postsurgical state) in this population. This study investigates how age, severity of illness, and mechanical ventilation are related to resting energy expenditure (REE) and nitrogen balance. Nineteen critically ill children (mean age, 8 +/- 6 [SD] y and range 0.4-17.0 y) receiving total parenteral nutrition (TPN) were enrolled. We used indirect calorimetry to measure REE. Expected energy requirements (EER) were obtained from Talbot tables. Pediatric Risk of Mortality (PRISM) and Therapeutic Intervention Scoring System (TISS) score were calculated. Total urinary nitrogen was measured using the Kjeldahl method. PRISM and TISS scores were 9 +/- 5 and 31 +/- 6 points, respectively. REE was 62 +/- 25 kcal.kg-1.d-1, EER was 42 +/- 11 kcal.kg-1. d-1, and caloric intake was 49 +/- 22 kcal.kg-1.d-1. Nitrogen intake was 279 +/- 125 mg.kg-1.d-1, total urinary nitrogen was 324 +/- 133 mg.kg-1.d-1, and nitrogen balance was -120 +/- 153 mg.kg-1.d-1. The protein requirement in this population was approximately 2.8 g.kg-1.d-1. These critically ill children were hypermetabolic, with REE 48% higher (20 kcal.kg-1.d-1) than expected. Nitrogen balance significantly correlated with caloric and protein intake, urinary nitrogen, and age, but not with severity of illness scores or ventilatory parameters.
Asunto(s)
Enfermedad Crítica , Metabolismo Energético , Nitrógeno/metabolismo , Respiración Artificial , Adolescente , Niño , Preescolar , Cuidados Críticos , Proteínas en la Dieta/administración & dosificación , Ingestión de Energía , Eritema Multiforme/metabolismo , Femenino , Infecciones por VIH/metabolismo , Humanos , Lactante , Masculino , Nitrógeno/orina , Neumonía/metabolismo , Neumonía por Pneumocystis/metabolismo , Descanso , Sepsis/metabolismoRESUMEN
The use of prediction equations has been recommended for calculating energy expenditure. We evaluated two equations that predict energy expenditure, each of which were corrected for two different stress factors, and compared the values obtained with those calculated by indirect calorimetry. The subjects were 55 critically ill children on mechanical ventilation. Basal metabolic rates were calculated with the Harris-Benedict and Talbot methods. Measured resting energy expenditure was 4.72 +/- 2.53 MJ/d. The average difference between measured resting energy expenditure and the Harris-Benedict prediction with a stress factor of 1.5 was -0.98 MJ/d, with an SD delta of 1.56 MJ/d and limits of agreement from -4.12 to 2.15; for a stress factor of 1.3 the average difference was -0.22 MJ/d, with an SD delta of 1.57 MJ/d and limits of agreement from -3.37 to 2.93. The average difference between measured resting energy expenditure and the Talbot prediction with a stress factor of 1.5 was -0.23 MJ/d, with an SD delta of 1.36 MJ/d and limits of agreement from -2.95 to 2.48; for a stress factor of 1.3, it was 0.42 MJ/d, with an SD delta of 1.24 MJ/d and limits of agreement from -2.04 to 2.92. These limits of agreement indicate large differences in energy expenditure between the measured value and the prediction estimated for some patients. Therefore, neither the Harris-Benedict nor the Talbot method will predict resting energy expenditure with acceptable precision for clinical use. Indirect calorimetry appears to be the only useful way of determining resting energy expenditure in these patients.
Asunto(s)
Calorimetría Indirecta/métodos , Enfermedad Crítica , Metabolismo Energético/fisiología , Consumo de Oxígeno/fisiología , Respiración Artificial , Adulto , Metabolismo Basal/fisiología , Niño , Preescolar , Interpretación Estadística de Datos , Femenino , Humanos , Lactante , Recién Nacido , Unidades de Cuidado Intensivo Pediátrico , Masculino , Valor Predictivo de las PruebasRESUMEN
Patients with toxic epidermal necrolysis, a severe, exfoliative skin disorder, have clinical features similar to those of partial-thickness burn patients. The literature suggests that they also have similar nutritional requirements. We report two patients diagnosed with toxic epidermal necrolysis on mechanical ventilation, in whom resting energy expenditure and respiratory quotient were measured by indirect calorimetry. The patients were treated using standard burn protocols. Nitrogen balance was calculated by measuring total urinary nitrogen in urine samples obtained over 24 hours. These measurements were done while the patients were on mechanical ventilation and receiving total parenteral nutrition. As in burn patients, early in their course the two patients had resting energy expenditure values twice that predicted. After 12 days of hospitalization, nitrogen balance was negative in patient 1 and positive in patient 2. Energy and protein requirements appear to have been related to the amount of body surface affected.