tailieunhanh - Ebook Evidence-based critical care (3rd edition): Part 2

(BQ) Part 2 book "Evidence-based critical care" presents the following contents: Arterial blood gas analysis, acute severe asthma, pleural effusions and atelectasis, hypertensive crises, acute decompensated cardiac failure, acute coronary syndromes, stress ulcer prophylaxis, acute and chronic liver disease,. | Chapter 22 Arterial Blood Gas Analysis Arterial blood gas ABG analysis plays a pivotal role in the management of critically ill patients. Although no randomized controlled study has ever been performed evaluating the benefit of ABG analysis in the ICU it is likely that this technology stands alone as that diagnostic test which has had the greatest impact on the management of critically ill patients this has likely been translated into improved outcomes. Prior to the 1960s clinicians were unable to detect hypoxemia until clinical cyanosis developed. ABG analysis became available in the late 1950s when techniques developed by Clark Stow and coworkers and Severinghaus and Bradley permitted the measurement of the partial pressures of oxygen PaO2 and carbon dioxide PaCO2 1-3 . The ABG remains the definitive method to diagnose categorize and quantitate respiratory failure. In addition ABG analysis is the only clinically applicable method of assessing a patient s acid-base status. ABGs are the most frequently ordered test in the ICU and have become essential to the management of critically ill patients 4 . Indeed a defining requirement of an ICU is that a clinical laboratory should be available on a 24-h basis to provide blood gas analysis 5 . Indications for ABG Sampling ABGs are reported to be the most frequently performed test in the ICU 4 . There are however no published guidelines and few clinical studies which provide guidance as to the indications for ABG sampling 6 . It is likely that many ABGs are performed unnecessarily. Muakkassa and coworkers studied the relationship between the presence of an arterial line and ABG sampling 7 . These authors demonstrated that patients with an arterial line had more ABGs drawn than those who did not regardless of the value of the PaO2 PaCO2 APACHE II score or the use of a ventilator. In this study multivariate analysis demonstrated that the presence of an arterial line was the most powerful predictor of the number of ABGs drawn