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Arterial Hypoxemia (arterial + hypoxemia)

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Medical Sciences	100%

Selected Abstracts

Comparison of desaturation and resaturation response times between transmission and reflectance pulse oximeters

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010
S. J. CHOI
Background: In general, there is a response time between actual arterial hypoxemia and its detection by pulse oximeters. We compared the desaturation and resaturation response times between two types of pulse oximeters, transmission and reflectance pulse oximeters, to find out which oximeter has a more rapid response time. Methods: Thirty-three ASA 1 or 2 patients were enrolled in this study. A transmission pulse oximeter was placed on the index finger and a reflectance pulse oximeter was placed on the forehead and monitored simultaneously. After the induction of general anesthesia without pre-oxygenation, we waited until the oxygen saturation value of any of two pulse oximeters declined to 90%, and then mask ventilation was started with 100% oxygen. Oxygen saturation was recorded at an interval of 2 s during this time. Results: The desaturation response time of SpO2 to 95% after apnea was 82.0 s (interquartile range: 67.0,98.5 s) vs. 94.0 s (interquartile range: 84.0,106.5 s) (P<0.001) and SpO2 to 90% was 94.0 s (interquartile range: 75.5,109.5 s) vs. 100.0 s (interquartile range: 84.5,114.5 s) (P<0.001) in the reflectance and transmission oximeters, respectively. The resaturation response time from mask ventilation to 100% SpO2 was 23.2±5.6 vs. 28.9±7.6 s (P<0.001) in the reflectance and transmission oximeters, respectively. Conclusion: In clinical situations in which rapid changes in oxygen saturation are expected, we recommend the forehead reflectance pulse oximeter because it responds more quickly in detecting oxygen desaturation and resaturation compared with the transmission pulse oximeter. [source]

Utility of pulse oximetry in the detection of arterial hypoxemia in liver transplant candidates

LIVER TRANSPLANTATION, Issue 4 2002
Gary A. Abrams MD Assistant Professor of Medicine
Hepatopulmonary syndrome, arterial hypoxemia caused by intrapulmonary vasodilatation, occurs in approximately 10% of patients with cirrhosis. The severity of hypoxemia affects liver transplant candidacy and is associated with increased morbidity and mortality posttransplantation. Screening guidelines for detecting the presence of arterial hypoxemia do not exist. The aim of this study is to investigate the accuracy and utility of pulse oximetry in the detection of hypoxemia (PaO2 < 70 mm Hg) in patients with cirrhosis. Two hundred prospective liver transplant candidates were compared with 94 controls. Arterial oxyhemoglobin saturation was obtained by pulse oximetry (SpO2) and compared with simultaneous arterial blood gas (ABG) oxyhemoglobin values (SaO2; bias = the difference). PaO2, carboxyhemoglobin, methemoglobin, and routine clinical and biochemical parameters were investigated to account for the bias. SpO2 overestimated SaO2 in 98% of patients with cirrhosis (mean bias, 3.37%; range, ,1% to 10%). Forty-four percent of patients with cirrhosis and controls had a bias of 4% or greater. No clinical or biochemical parameters of cirrhosis accounted for the overestimation of pulse oximetry. Twenty-five subjects with cirrhosis were hypoxemic, and an SpO2 of 97% or less showed a sensitivity of 96% and a positive likelihood ratio of 3.9 for detecting hypoxemia. An SpO2 of 94% or less detected all subjects with an arterial PaO2 less than 60 mm Hg. Pulse oximetry significantly overestimates arterial oxygenation, and the inaccuracy is not influenced by liver disease. Nevertheless, pulse oximetry can be a useful screening tool to detect arterial hypoxemia in patients with cirrhosis, but a higher threshold for obtaining an ABG must be used. [source]

Childhood cirrhosis, hepatopulmonary syndrome and liver transplantation

PEDIATRIC TRANSPLANTATION, Issue 3 2008
Gokhan Tumgor
Abstract:, Objectives:, The hepatopulmonary syndrome (HPS) is characterized as a triad: liver disease, intrapulmonary vascular dilatatiton, and arterial hypoxemia. The aim of this study is to analyze outcome of children with HPS in liver transplant era. Methods:, Between September 1996 and November 2006, 172 cirrhotic patients (median age 5 years; range 0.2,22 years, M/F; 97/75) were followed at Ege University Pediatric Gastroenterology, Hepatology and Nutrition Unit. All patients were evaluated by chest radiography, arterial blood gas analysis, and alveolar-arterial oxygen tension difference, contrast echocardiography (CEE) after and before the liver transplantation. Results:, HPS was diagnosed in 33 patients (19%) by CEE. None of them had pulmonary hypertension. HPS was not found related to etiology of the liver disease. Portal hypertension was found related to the development of HPS (75.7% in patients with HPS and 54.6% in others, p = 0.02). 17 of 33 patients with HPS underwent liver transplantation. Preoperative and postoperative period of these patients was uneventful. Patients were extubated in the operating room except for two. Median follow up of transplanted children was 1.9 year (range; 0.75,10 years). Arterial blood gas analysis and CEE positivity regressed in all of them by postoperative 6th month. Conclusions:, HPS is a serious and important complication of cirrhotic children that leads to tissue hypoxia and central cyanosis. HPS seems reversible after liver transplantation in all patients. [source]