Effect of the route of nutrition and L-alanyl-L-glutamine supplementation in amino acids' concentration in trauma patients.

PURPOSE: Our purpose was to assess the amino acids' (AAs) profile in trauma patients and to assess the effect of the route of nutrition and the exogenous ALA-GLN dipeptide supplementation on plasma AAs' concentration. METHODS: This is a secondary analysis of a previous randomized controlled trial. On day 1 and day 6 after trauma, plasma concentration of 25 AAs was measured using reverse phase high-performance liquid chromatography. Results were analyzed in relation to the route of nutrition and supplementation of ALA-GLN dipeptide. Differences between plasma AAs' concentrations at day 1 and day 6 were evaluated using the Student's t test or Mann-Whitney-Wilcoxon test. One-way ANOVA and the Kruskal-Wallis test were used to compare groups. A two-sided p value less than 0.05 was considered statistically significant. RESULTS: Ninety-eight patients were analyzed. Mean plasma concentrations at day 1 were close to the lower normal level for most AAs. At day 6 we found an increase in the eight essential AAs' concentrations and in 9 out of 17 measured non-essential AAs. At day 6 we found no differences in plasma concentrations for the sum of all AAs (p = .72), glutamine (p = .31) and arginine (p = .23) distributed by the route of nutrition. Administration of ALA-GLN dipeptide increased the plasma concentration of alanine (p = .004), glutamine (p < .001) and citrulline (p = .006). CONCLUSIONS: We found an early depletion of plasma AAs' concentration which partially recovered at day 6, which was unaffected by the route of nutrition. ALA-GLN dipeptide supplementation produced a small increase in plasma levels of glutamine and citrulline.

Enteral nutrition volume is not correlated with lower respiratory tract infection in patients on mechanical ventilation.

OBJECTIVE: To evaluate the effect of enteral nutrition volume, gastrointestinal function and the type of acid suppressive drug upon the incidence of lower respiratory tract infections in critically ill patients on mechanical ventilation (MV). DESIGN: A retrospective secondary analysis was carried out. SETTING: The Intensive Care Unit of a University Hospital. PATIENTS OR PARTICIPANTS: Patients≥18-years-old expected to need MV for more than four days, and receiving enteral nutrition by nasogastric tube within 24h of starting MV. INTERVENTIONS: We correlated enteral nutrition volume administered during the first 10 days, gastrointestinal function and the type of acid suppressive therapy with the episodes of lower respiratory tract infection up until day 28. Cox proportional hazards ratios in univariate and adjusted multivariate models were used. Statistical significance was considered for p<0.05. MAIN VARIABLES OF INTEREST: Lower respiratory tract infection episodes. RESULTS: Sixty-six out of 185 patients (35.7%) had infection; 27 patients had ventilator-associated pneumonia; and 39 presented ventilator-associated tracheobronchitis. Uninfected and infected groups were similar in terms of enteral nutrition volume (54±12 and 54±9mL/h; p=0.94) and caloric intake (19.4±4.9 and 19.6±5.2kcal/kg/d; p=0.81). The Cox proportional hazards model showed neurological indication of MV to be the only independent variable related to infection (p=0.001). Enteral nutrition volume, the type of acid suppressive therapy, and the use of prokinetic agents were not significantly correlated to infection. CONCLUSIONS: Enteral nutrition volume and caloric intake, gastrointestinal dysfunction and the type of acid suppressive therapy used were not associated to lower respiratory tract infection in patients on MV.

Effect of FiO2 in the measurement of VO2 and VCO2 using the E-COXV metabolic monitor. / Efecto de la FiO2 sobre la medición del VO2 y la VCO2 con el monitor metabólico E-COVX.

OBJECTIVE: We evaluated the effect of changes in FiO2 on the bias and accuracy of the determination of oxygen consumption (V˙O2) and carbon dioxide production (V˙CO2) using the E-COVX monitor in patients with mechanical ventilation. DESIGN: Descriptive of concordance. SETTING: Intensive Care Unit. PATIENTS OR PARTICIPANTS: Patients with mechanical ventilation. INTERVENTIONS: We measured V˙O2 and V˙CO2 using the E-COVX monitor. Values recorded were the average in 5min. Two groups of 30 patients. We analyzed: 1) the reproducibility in the measurement of V˙O2 and V˙CO2 at FiO2 0.4, and 2) the effect of the changes in FiO2 on the measurement of V˙O2 and V˙CO2. Statistical analysis was performed using Bland and Altman test. VARIABLES OF MAIN INTEREST: Bias and accuracy. RESULTS: 1) FiO2 0.4 reproducibility: The bias in the measurement of V˙O2 and V˙CO2 was 1.6 and 2.1mL/min, respectively, and accuracy was 9.7 to -8.3% and 7.2 to -5.2%, respectively, and 2) effect of FiO2 on V˙O2: The bias of V˙O2 measured at FiO2 0.4 and 0.6 was -4.0mL/min and FiO2 0.4 and 0.8 was 5.2mL/min. Accuracy between FiO2 0.4 and 0.6 was 11.9 to -14.1%, and between FiO2 0.4 and 0.8 was 43.9 to -39.7%. CONCLUSIONS: The E-COVX monitor evaluates V˙O2 and V˙CO2 in critical patients with mechanical ventilation with a clinically acceptable accuracy until FiO2 0.6.

El volumen de nutrición enteral no se correlaciona con las infecciones del tracto respiratorio inferior en pacientes con ventilación mecánica / The volume of enteral nutrition does not correlate with lower respiratory tract infections in patients with mechanical ventilation

Objetivo. Valorar el efecto del volumen de nutrición enteral, la función gastrointestinal y el tipo de protección gástrica en la incidencia de infección respiratoria del tracto inferior en pacientes críticos con ventilación mecánica (VM). Diseño Análisis secundario retrospectivo. Ámbito La Unidad de Cuidados Intensivos de un hospital universitario. Pacientes o participantes Pacientes con edad≥18 años que se espera que precisen de VM durante>4 días y reciban nutrición enteral en las primeras 24h. Intervenciones Correlacionamos el volumen de nutrición enteral administrado durante los primeros 10 días, la función gastrointestinal y el tipo de protección gástrica con los episodios de infección pulmonar del tracto inferior hasta el día 28. Utilizamos el modelo de regresión de Cox. Un valor de p<0,05 fue considerado estadísticamente significativo. Principal variable de interés Episodios de infección del tracto respiratorio inferior. Resultados Sesenta y seis de los 185 pacientes (35,7 por ciento) presentaron infección, 27 pacientes neumonía y 39 traqueobronquitis. Los pacientes no infectados e infectados fueron similares en el volumen de nutrición enteral (54±12 y 54±9mL/h; p=0,94) y aporte calórico (19,4±4,9 y 19,6±5,2kcal/kg/d; p=0,81). El modelo de regresión de Cox mostró que la causa neurológica de VM fue la única variable independiente asociada con infección (p=0,001). El volumen de nutrición enteral, el tipo de protección gástrica y la función gastrointestinal no se correlacionaron significativamente con la infección. Conclusiones El volumen y aporte calórico de nutrición enteral, la disfunción gastrointestinal y el tipo de protección gástrica no se asociaron a la infección del tracto respiratorio inferior en pacientes con VM.

Respiratory CO2 response depends on plasma bicarbonate concentration in mechanically ventilated patients.

OBJECTIVE: There is controversy about the effects of high plasma bicarbonate concentration ([HCO3(-)]) and the CO2 response test. We analyzed the relationship between [HCO3(-)] and the variation in hydrogen ion concentration (pH) for a given change in PaCO2, and its effects upon CO2 response. DESIGN: A retrospective study was carried out. SETTING: Two intensive care units. PATIENTS: Subjects with and without chronic obstructive pulmonary disease (COPD), at the beginning of weaning from mechanical ventilation. INTERVENTIONS: The CO2 response was evaluated by the re-inhalation of expired air method, measuring the hypercapnic ventilatory response (ΔVE/ΔPaCO2) and hypercapnic drive response (ΔP01/ΔPaCO2), where VE is minute volume and P0.1 is airway occlusion pressure 0.1s after the initiation of inspiration. MAIN OUTCOME MEASURES: [HCO3(-)] and CO2 response. RESULTS: A total of 120 patients in the non-COPD group and 48 in the COPD group were studied. COPD patients had higher mean [HCO3(-)] than non-COPD patients (33.2 ± 5.4 vs. 25.7 ± 3.7 mmol/l, p<0.001). In both non-COPD and COPD patients we observed a significant inverse linear relationship between [HCO3(-)] and pH change per mmHg of PaCO2 (p<0.001), ΔVE/ΔPaCO2 (p<0.001) and ΔP0.1/ΔPaCO2 (p<0.001). CONCLUSIONS: There is an inverse linear relationship between [HCO3(-)] and the variation of pH for a given change in PaCO2 and the CO2 response.

Respiratory CO2 response in acute cervical spinal cord injury (CO2 response in spinal cord injury).

STUDY DESIGN: Retrospective study. OBJECTIVES: The objective of this study was to compare the CO2 response of acute tetraplegic cervical spinal cord injury (SCI) patients undergoing mechanical ventilation with a control group of critically ill patients ready for weaning of mechanical ventilation and successfully extubated. SETTING: This study was conducted at the intensive care unit of a University Hospital in Mallorca, Spain. METHODS: CO2 response was studied in 12 acute tetraplegic cervical SCI patients at the C4-C7 level and 22 control patients. The control group patients were consecutively selected from a database of patients with mechanical ventilation and who were successfully extubated after a CO2 response test. To increase the CO2 , we used the method of re-inhalation of expired air, and we evaluated the hypercapnic ventilatory response, the change in minute ventilation induced by the increase of partial pressure of arterial carbon dioxide (PaCO2 ), which measures the whole respiratory system (metabolic control, neuromuscular or ventilatory apparatus), and the hypercapnic drive response, the change in the airway occlusion pressure at 100 ms induced by the increase in PaCO2, which measures the chemosensitivity of the respiratory center. RESULTS: Cervical SCI patients were younger than the control group patients (26±7 and 62±12 years, respectively; P<0.001). Mean values of the hypercapnic ventilatory response in cervical SCI and control groups were 0.52±0.31 and 0.64±0.33 l min(-1) per mm Hg (P=0.40), respectively, and the hypercapnic drive response was 0.24±0.16 and 0.48±0.23 cm H2O per mm Hg (P=0.001), respectively. CONCLUSION: Acute tetraplegic cervical SCI patients had reduced hypercapnic drive response that may contribute to the difficult weaning, without reduction in hypercapnic ventilatory response.

[Efficacy of the dipeptide N(2)-L-Alanyl-L-glutamine in traumatic patients admitted to the ICU: a prospective, randomized, double-blind, multicentre study]. / Eficacia del dipéptido N(2)-L-Alanil-L-glutamina en los pacientes traumáticos ingresados en la UCI: estudio prospectivo, multicéntrico, aleatorizado y doble ciego; hipótesis y protocolo.

HYPOTHESIS: the endovenous administration of glutamine, independently of the type of nurtrition received, can reduce the ICU length of stay, the incidence of infections and the mortality in the traumatic patients admitted to the ICU. OBJECTIVES: The main objective is to assess the efficacy of glutamine suplementation, given intravenously, to reduce the incidence of infectious complications, mortality and ICU length of stay in the traumatic patients admitted to the ICU. Other objectives are: 1) to assess the efficacy of glutamine in different groups of patients according to the severity and the plasma levels of glutamine. 2) Record all the adverse events due to the intravenous administration of glutamine. METHODS: prospective, randomized, doble-blind and multicenter study with two parallel groups: placebo and treatment group. The patients who fulfill the inclusion criteria will receive either glutamine or placebo, independently of the type on nutrition. Glutamine will be administered as a pharmaconutrient at 0.5 g/kg/day during 5 days as a continous perfusion.

Long-term follow-up of patients with post-traumatic refractory high intracranial pressure treated with lumbar drainage.

Drainage of cerebrospinal fluid by means of external lumbar drainage (ELD) is controversial in the adult population with traumatic brain injury. We report our experience with ELD in the treatment of post-traumatic high intracranial pressure (ICP) and the results of the long-term follow-up in these patients. We undertook clinical evaluation of 30 patients with traumatic brain injury and high ICP treated with second-tier measures or with first-tier measures if second-tier measures were contraindicated. The study involved a retrospective review of collected data. Outcome at intensive care unit discharge and three to five years after injury were evaluated with the Glasgow Outcome Scale. The mean age of patients was 34.9 +/- 12.5 years and 25 (83%) were male. The median (interquartile range) Glasgow Coma score was 8 (7 to 10). ICP before and one hour after ELD placement was 33.7 +/- 9.0 and 12.5 +/- 4.8 mmHg respectively, a decrease in 21.2 +/- 8.3 mmHg (P < 0.0001). ELD was placed after a mean of 8.6 +/- 3.9 days. Cerebrospinal fluid drainage was maintained for a mean of 6.6 +/- 3.5 days. Four patients (13%) required ELD replacement and one patient developed a cerebrospinal fluid infection (3%). No pupillary changes were noted within 48 hours of ELD placement. Long-term outcome was favourable (good recovery or moderate disability) in 62% of the patients studied. The use of ELD resulted in a marked decrease in ICP These patients presented a good outcome in 62% of the cases in the long-term evaluation. Few complications related with ELD use were noted.

Correlation between brain interstitial and total serum cortisol levels in traumatic brain injury. A preliminary study.

INTRODUCTION: Brain cortisol availability has never been evaluated in patients with traumatic brain injury (TBI). Cerebral microdialysis is a well-established technique for monitoring brain metabolism in neurocritically ill patients, which may be used to measure interstitial cortisol. The objective of this preliminary study was to measure brain interstitial cortisol and its correlation with total serum cortisol in patients with TBI. METHODS: We prospectively studied 6 patients with severe TBI admitted to the Intensive Care Unit of our tertiary University Hospital in which multimodal neuromonitoring including cerebral microdialysis with a high cut-off of 100 k-Da and 20-mm long membrane was used. Serum and brain interstitial cortisol microdialysis samples were obtained every 8 h and analyzed afterwards. RESULTS: Linear regression analysis of total serum cortisol and brain interstitial cortisol in the whole population showed a moderate correlation (R2=0.538, p<0.001, no.=118). However, intra-individual correlation showed a great variability, with correlation coefficients ranging from a R2=0.091 to R2=0.680. CONCLUSION: Our prospective and preliminary study showed a moderate correlation of brain interstitial cortisol and total serum cortisol values in patients with diffuse TBI. However, intra-individual analysis showed a great variability. These results suggest that total serum cortisol may not reflect brain cortisol availability in half of TBI patients.

Síndrome serotoninérgico por interacción entre linezolid, triptófano y metoclopramida / Serotonin syndrome due to interaction between linezolid, tryptophan, and metoclopramide

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Hypercapnia test and weaning outcome from mechanical ventilation in COPD patients.

We evaluated the hypercapnia response test as a weaning outcome predictor from mechanical ventilation in patients with chronic obstructive pulmonary disease (COPD). We studied 44 COPD intubated patients considered ready for a weaning trial. The hypercapnia test was based on the modified method of re-inhalation of expired air Through the hypercapnic test we calculated the ratio of the change in minute volume (V(E)) to the change in PaCO2 (deltaV(E)/deltaPaCO2), the change in airway occlusion pressure at 0.1 second of inspiration (P0.1) to change in PaCO2 (deltaP0.1/deltaPACO2), the ratio of the change in P0.1 to baseline PaCO2 (deltaP0.1/PaCO2) and the ratio of the change in V(E) to baseline PaCO2 (deltaV(E)/PaCO2). Nineteen patients were successfully weaned and 25 patients failed. No differences in baseline clinical characteristics were found between the two groups. Weaning failure COPD patients had lower deltaP0.1/deltaPaCO2 (0.19 +/- 0.11 and 0.34 +/- 0.20 cm H2O/mmHg respectively, P = 0.006) and lower deltaV(E)/deltaPaCO2 (0.21 +/- 0.15 and 0.40 +/- 0.22 l/min/mmHg respectively, P = 0.002) than successfully weaned patients. The area under the receiver operating characteristic curve to discriminate weaning outcome was for the baseline PaCO2 0.81 (95% confidence interval: 0.66 to 0.91), hypercapnic PaCO2 0.76 (0.61 to 0.88), hypercapnic drive response 0.74 (0.59 to 0.86), hypercapnic ventilatory response 0.76 (0.60 to 0.87), deltaP0.1/PaCO2 0.76 (0.60 to 0.87) and for the deltaV(E)/PaCO2 0.81 (0.67 to 0.91). COPD patients with weaning failure have a significantly more blunted response to the hypercapnia response test than weaning success patients. This test could be useful to predict weaning failure patients if the combined values of the hypercapnic drive and hypercapnic ventilatory response were below the threshold values.

[Immediate hemodynamic response to steroid treatment in septic shock]. / Respuesta hemodinámica precoz a los corticoides en el shock séptico.

OBJECTIVE: Treatment with low dose steroids (LDST) in patients with septic shock treated with vasoactive agents has been related to earlier shock reversal. Patients with low baseline cortisol and a blunted response to the corticotropin test are more likely to benefit from LDST, so we compared the immediate hemodynamic response in patients with septic shock who received LDST with that of those who did not receive LDST. DESIGN: Retrospective study. SCOPE: Intensive Care Unit (ICU) of a tertiary university hospital. PATIENTS: We studied 96 patients admitted to the ICU. Patients were classified in two groups of 48 patients: group A received LDST and group B did not; patients were matched according to baseline cortisol levels and norepinephrine requirements. INTERVENTIONS: All patients underwent a short corticotropin test (250 microg ACTH) within 72 h of septic shock onset. MAIN VARIABLES OF INTEREST: Baseline cortisol, delta cortisol, peak cortisol, norepinephrine reduction after LDST, and duration of shock. RESULTS: The two groups were comparable: baseline and stimulated cortisol levels before corticotropin test were similar, and there were no differences in the norepinephrine dose before and 24 h after testing adrenal response (p = 0.98 and p = 0.53, respectively). Norepinephrine reduction at 24 h after testing was not correlated with baseline cortisol or with adrenal response to the corticotropin test. CONCLUSIONS: LDST was not associated to improved 24-hour hemodynamic response, irrespective of the baseline and stimulated cortisol levels.

Respuesta hemodinámica precoz a los corticoides en el shock séptico / Immediate hemodynamic response to steroid treatment in septic shock

Objetivo. El tratamiento con corticoides a dosis bajas (LDST) en los pacientes con shock séptico tratados con soporte vasoactivo se ha asociado a una disminución del tiempo de shock. Los pacientes con cortisol basal disminuido o con respuesta anormal a la estimulación suprarrenal deberían tener un mayor beneficio con los LDST, por lo que hemos estudiado la respuesta hemodiná-mica precoz en pacientes con shock séptico tratados o no con LDST. Diseño. Estudio retrospectivo. Ámbito. Unidad de cuidados intensivos (UCI) en un hospital universitario de tercer nivel. Pacientes. Estudiamos a 96 pacientes ingresados en la UCI, distribuidos en dos grupos de 48 pacientes según hubieran recibido corticoides (grupo A) o no (grupo B), apareados según los valores de cortisol basal y los requerimientos de noradrenalina. Intervenciones. A todos los pacientes, se realizó un test de estimulación suprarrenal con 250 μg de corticotrofina en las primeras 72 h del inicio del shock. Variables principales de interés. Cortisol basal, incremento de cortisol, cortisol máximo, reducción de la dosis de noradrenalina, duración del shock. Resultados. Ambos grupos fueron comparables. Las cifras de cortisol basal antes del test de estimulación suprarrenal y el cortisol máximo fueron similares en ambos grupos. No hubo diferencias significativas entre ambos grupos en la dosis de noradrenalina antes y a las 24 h tras la estimulación suprarrenal. La reducción en la dosis de noradrenalina a las 24 h no se correlacionó con las cifras de cortisol basal ni con la respuesta a la estimulación suprarrenal. Conclusiones. El tratamiento con LDST no se asoció a una mejoría hemodinámica a las 24 h, independientemente de las cifras de cortisol basal y de la respuesta a la estimulación suprarrenal

Objective. Treatment with low dose steroids(LDST) in patients with septic shock treated withvasoactive agents has been related to earliershock reversal. Patients with low baseline cortisoland a blunted response to the corticotropin testare more likely to benefit from LDST, so we comparedthe immediate hemodynamic response inpatients with septic shock who received LDSTwith that of those who did not receive LDST.Design. Retrospective study.Scope. Intensive Care Unit (ICU) of a tertiaryuniversity hospital.Patients. We studied 96 patients admitted tothe ICU. Patients were classified in two groups of48 patients: group A received LDST and group Bdid not; patients were matched according tobaseline cortisol levels and norepinephrine requirements.Interventions. All patients underwent a shortcorticotropin test (250 g ACTH) within 72 h ofseptic shock onset.Main variables of interest. Baseline cortisol,delta cortisol, peak cortisol, norepinephrine reductionafter LDST, and duration of shock.Results. The two groups were comparable:baseline and stimulated cortisol levels before corticotropintest were similar, and there were no differencesin the norepinephrine dose before and24 h after testing adrenal response (p = 0.98 and p= 0.53, respectively). Norepinephrine reduction at24 h after testing was not correlated with baselinecortisol or with adrenal response to the corticotropintest.Conclusions. LDST was not associated to improved24-hour hemodynamic response, irrespectiveof the baseline and stimulated cortisollevels

Effect of barbiturate coma on adrenal response in patients with traumatic brain injury.

INTRODUCTION: Barbiturate coma is the second tier measure recommended by guidelines to treat post-traumatic refractory intracranial pressure. Systemic hypotension is its most important side effect. Recent evidence suggests that low-dose corticosteroid therapy may be used in a subset of patients with traumatic brain injury (TBI) to avoid hypotension. We evaluated adrenal function in TBI patients undergoing barbiturate coma, as treatment of their refractory intracranial hypertension. MATERIALS AND METHODS: We prospectively studied 40 patients with moderate to severe TBI. Group A (17 patients) were treated with barbiturate coma. Group B (23 patients) presented intracranial hypertension controlled with first tier measures, and acted as a control. Adrenal function was evaluated by using the high-dose corticotropin stimulation test within 24 h after brain injury and after barbiturate coma induction. RESULTS: Within 24 h after TBI, adrenal function was similar in both groups. Once barbiturate coma was induced, patients in group A treated with barbiturate coma presented a higher incidence of adrenal insufficiency compared with the control group B (53% vs 22%, p=0.03). Patients treated with barbiturates, who developed adrenal impairment, required higher doses of norepinephrine to maintain cerebral perfusion pressure than patients treated with barbiturates without adrenal impairment (1.07+/-1.04 microg/kg/min vs 0.31+/-0.32 mug/kg/min, p=0.03). CONCLUSIONS: Patients with TBI treated with barbiturate coma are at higher risk of developing adrenal insufficiency. This subset of patients presented higher requirements of vasoactive support to avoid hypotension. In these patients corticosteroid therapy may have potential therapeutic implications to treat hemodynamic instability.

[Oxygen cost of breathing in the prediction of successful weaning from mechanical ventilation]. / Coste de oxígeno de la respiración y predicción del éxito de la desconexión de la ventilación mecánica.

OBJECTIVE: To determine whether the oxygen cost of breathing (VO2 resp) may predict successful weaning from mechanical ventilation. DESIGN: A prospective clinical study. SETTING: A polyvalent intensive care unit of a teaching hospital. PATIENTS: Thirty non-consecutive mechanically ventilated patients ready to wean. Successful weaning was considered when reintubation was not needed for 48 h after extubation. INTERVENTIONS: Spontaneous breathing test with a t-tube. VO2 resp was measured with the Douglas bag method. RESULTS: Successful weaning was present in 20 (67%) of 30 patients. No patient with successful weaning needed tracheal reintubation. A cut-off value for VO2 resp