ABSTRACT
Antecedentes: El procedimiento de tomar las muestras de gases arteriales puede ser técnicamente difícil y tiene limitaciones y complicaciones. La colocación de un catéter venoso central es un procedimiento obligado en la unidad de cuidados intensivos (UCI). La toma de muestras de sangre venosa central es mucho más fácil y rápida, y menos complicada. Contexto: Correlación y concordancia entre los valores de pH, PO2, PCO2 y HCC3 en sangre arterial y venosa central de pacientes con ventilación mecánica. Objetivo: El objetivo era evaluar la correlación y la concordancia entre los valores de pH, PO2, PCO2 y HCC3 en sangre arterial y venosa central e inferir si los valores de los gases venosos centrales podían reemplazar la lectura de los gases arteriales. Lugar y diseño: UCI y estudio prospectivo de tipo observacional. Materiales y métodos: Se tomaron en total 100 muestras (50 gases arteriales y 50 gases venosos centrales) de 50 pacientes adultos con distintos procesos patológicos ingresados en la UCI de un hospital universitario. Se ingresaron en el estudio los pacientes normotensos y normotérmicos que requirieron ventilación mecánica y tenían arteria radial palpable. No se repitió ningún paciente en el estudio. En cada paciente se tomó primero la muestra de sangre arterial de la arteria radial y 2 min después se tomó la muestra de sangre venosa central. Se evaluaron la correlación y la concordancia entre los valores de pH, PO2, PCO2 y HCO3 - en sangre arterial y venosa central. Análisis estadístico utilizado: Correlación de Pearson y análisis de Bland Altman. Resultados: Se encontró una correlación significativa entre los valores venosos y arteriales de pH, PO2, PCO2 y HCO3 (r pH = 0,88, p< 0,001; rP02 = 0,358, p<0,05; rPC0(2) = 0,470, p< 0,001 y rHC03 = 0,714, p< 0,001). Se derivaron ecuaciones de regresión para predecir los valores en sangre arterial a partir de los valores en sangre venosa: pH arterial = 0,879 xpH venoso central +114,4 (constante), R² = 0,128, PC0(2) arterial = 0,429 x P0(2) venoso central + 24.627 (constante), R² = 0,2205 y HC0(3) arterial = 1.045 x HC0(3) venoso central+ 3.402 (constante), R² = 0,5101. La diferencia media de la lectura arterial menos la venosa para pH, P0(2), PC0(2), y bicarbonato fue de 0,053 ± 0,014, 56,04 ± 15,74, 2,20 ± 4,4 y 4,30 ± 1,64, respectivamente. Las gráficas de Bland-Altmanpara la concordancia de los valores de pH, P0(2), PC0(2) y bicarbonato mostraron límites de concordancia del 95% de -0,04 a 0,146, -52,51 a 164,59, -26,61 a 31,01 y -7,0 a 15,6, respectivamente. Conclusiones: Hubo una buena correlación entre los valores arteriales y venosos centrales de pH, P0(2), PC0(2) y HCO3 -. Sin embargo, solamente el valor venoso central del pH puede reemplazar el valor arterial del pH.
Background: The procedure for arterial blood sampling can be technically difficult with various limitations and complications. Central venous catheterization is a mandatory procedure in ICU. The sampling of central venous blood is much easier, quicker and less complicated. Context: Correlation and agreement between arterial and central venous blood pH, PO2, PCO2 and HCO3 − values of mechanically ventilated patients. Aims: Aim was to evaluate the correlation and agreement between arterial and central venous blood pH, PO2, PCO2 and HCO3 − values and infer whether central venous blood gas values could replace arterial blood gas values. Settings and design: Intensive Care Unit and prospective observational study. Materials and methods: A total of 100 samples (50 arterial blood gas and 50 central venous blood gas) were collected from 50 adult patients with varied disease process admitted in a medical college ICU. Patients requiring mechanical ventilation having palpable radial artery, normotensive and normothermic were enrolled for the study. No patient was repeated for the study. Arterial blood was collected from radial artery and within 2 minutes central venous blood was withdrawn from the same patient. Correlation and agreement were evaluated between arterial and central venous pH, PO2, PCO2 and HCO3 −. Statistical analysis used: Pearson's correlation and Bland-Altman analysis. Results: The pH, PO2, PCO2 and HCO3 − of CVBG correlated significantly with arterial values (r pH = 0.88, P < 0.001; rPO2 = 0.358, P < 0.05; rPCO2 = 0.470, P < 0.001 and rHCO3 = 0.714, P < 0.001). Regression equations were derived to predict arterial blood values from venous blood values as follows: arterial pH= 0.879×central venous pH+ 0.9422 (constant), arterial PO2 = 0.421×central venous PO2 + 114.4 (constant), R² = 0.128, arterial PCO2 = 0.429×central venous PO2 + 24.627 (constant), R² = 0.2205 and arterial HCO3 = 1.045×central venous HCO3 + 3.402 (constant), R² = 0.5101. The mean arterial minus venous difference for pH, PO2, PCO2, and bicarbonatewas 0.053±0.014, 56.04±15.74, 2.20±4.4 and 4.30±1.64 respectively. Bland-Altman plots for agreement of pH, PO2, PCO2, and bicarbonate showed 95% limits of agreement of −0.04 to 0.146, −52.51 to 164.59, −26.61 to 31.01 and −7.0 to 15.6, respectively. Conclusions: The arterial pH, PO2, PCO2 and HCO3 – values correlatedwell with central venous values. However, only the arterial pH value can replace the central venous pH value.
Subject(s)
HumansABSTRACT
CONTEXT: Snake bites are the common cause of morbidity and mortality in tropical countries. AIMS: To analyze the outcome of snake bite victims SETTINGS AND DESIGN: Retrospective analysis of data from Intensive care unit, Department of Anesthesiology. MATERIALS AND METHODS: All the patients admitted in the intensive care unit for snake bite management during the year May 2004 - April 2009 were retrospectively reviewed. The data included age, sex, month and time of incident, site of bite, dose of anti--snake venom, time of anti--snake venom, administration, duration of mechanical ventilation, complications and death of a victim. STATISTICAL ANALYSIS USED: Pearson's correlation test, paired samples t-test. RESULTS AND CONCLUSIONS: 113 patients reported to the Accident and Emergency with history of snake bite. 26 patients were referred to other hospital, 17 patients were brought dead, and 70 patients were admitted to the intensive care unit. In 59 snake-bite victims, maximum data could be recovered. Krait was the most common type of snake bite reported. There was a male preponderance (69.4%) with age ranging between 20 and 40 years (52.5%). The mean lag time (time elapsed between bite and first dose of anti--snake venom) was 5.3 ± 1.4 h and the mean anti-snake venom dose was 12.3 ± 2.4 vials. There was a positive and significant correlation between lag time and total dose of anti--snake venom (correlation coefficient =0.956, P<0.0001). Overall 72.9% patients required mechanical ventilation with a mean duration of 56.2 ± 16.1 h. 10.2% patients sustained cardiac arrest, 8.7% patients developed ventilator associated pneumonia, 6.7% suffered mild anti-snake venom reaction, 6.7% had hypotension and 5.1% patients developed renal failure. The overall mortality was 5.1%.
