29 Oct 09
Posted in Acid-Base disorders at 0:38 by Laci
By T Jansen J van Bommel, J Bakker
Crit Care Med 2009;37:2827-2839
To decide whether the use of blood lactate monitoring in critical care practice is appropriate. We performed a systematic health technology assessment as blood lactate monitoring has been implemented widely but its clinical value in critically ill patients has never been evaluated properly.
Data source
PubMed, other databases, and citation review.
Study selection
We searched for lactate combined with critically ill patients as the target patient population. Two reviewers independently selected studies based on relevance for the following questions: Does lactate measurement: 1) perform well in a laboratory setting? 2) provide information in a number of clinical situations? 3) relate to metabolic acidosis? 4) increase workers’ confidence? 5) alter therapeutic decisions? 6) result in benefit to patients? 7) result in similar benefits in your own setting? 
result in benefits which are worth the extra costs?
Data extraction and synthesis
We concluded that blood lactate measurement in critically ill patients: 1) is accurate in terms of measurement technique but adequate understanding of the (an)aerobic etiology is required for its correct interpretation; 2) provides not only diagnostic but also important prognostic information; 3) should be measured directly instead of estimated from other acid-base variables; 4) has an unknown effect on healthcare workers’ confidence; 5) can alter therapeutic decisions; 6) could potentially improve patient outcome when combined with a treatment algorithm to optimize oxygen delivery, but this has only been shown indirectly; 7) is likely to have similar benefits in critical care settings worldwide; and has an unknown cost-effectiveness.
Conclusions
The use of blood lactate monitoring has a place in risk-stratification in critically ill patients, but it is unknown whether the routine use of lactate as a resuscitation end point improves outcome. This warrants randomized controlled studies on the efficacy of lactate-directed therapy
Permalink
27 Oct 09
Posted in Heart failure/Cardiogenic shock, Monitoring at 0:01 by Laci
By C Torgersen, C Schmittinger, S Wagne, H Ulmer, J Takala, S Jakob and M Dunser
Critical Care 2009,13:R157
Despite the key role of hemodynamic goals, there are few data addressing the question as to which hemodynamic variables are associated with outcome or should be targeted in cardiogenic shock patients. The aim of this study was to investigate the association between hemodynamic variables and cardiogenic shock mortality.
Methods
Medical records and the patient data management system of a multidisciplinary intensive care unit (ICU) were reviewed for patients admitted because of cardiogenic shock. In all patients, the hourly variable time integral of hemodynamic variables during the first 24 hours after ICU admission was calculated. If hemodynamic variables were associated with 28-day mortality, the hourly variable time integral of drops below clinically relevant threshold levels was computed. Regression models and receiver operator characteristic analyses were calculated. All statistical models were adjusted for age, admission year, mean catecholamine doses and the Simplified Acute Physiology Score II (excluding hemodynamic counts) in order to account for the influence of age, changes in therapies during the observation period, the severity of cardiovascular failure and the severity of the underlying disease on 28-day mortality.
Results
One-hundred-nineteen patients were included. Cardiac index (CI) (P=0.01) and cardiac power index (CPI) (P=0.03) were the only hemodynamic variables separately associated with mortality. The hourly time integral of CI drops <3, 2.75 (both P=0.02) and 2.5 (P=0.03) L/min/m2 was associated with death but not that of CI drops <2 L/min/m2 or lower thresholds (all P>0.05). The hourly time integral of CPI drops <0.5-0.8 W/m2 (all P=0.04) was associated with 28-day mortality but not that of CPI drops <0.4 W/m2 or lower thresholds (all P>0.05).
Conclusions
During the first 24 hours after intensive care unit admission, CI and CPI are the most important hemodynamic variables separately associated with 28-day mortality in patients with cardiogenic shock. A CI of 3 L/min/m^2 and a CPI of 0.8 W/m2 were most predictive of 28-day mortality. Since our results must be considered hypothesis-generating, randomized controlled trials are required to evaluate whether targeting these levels as early resuscitation endpoints can improve mortality in cardiogenic shock.
Permalink
24 Oct 09
Posted in Fluid management at 0:46 by Laci
By D Chappell, M Jacob, K Hofmann-Kiefer, P Conzen, M Rehm
Anesthesiology 2008;109:723-740
Replacement of assumed preoperative deficits, in addition to generous substitution of an unsubstantiated increased insensible perspiration and third space loss, plays an important role in current perioperative fluid regimens. The consequence is a positive fluid balance and weight gain of up to 10 kg, which may be related to severe complications. Because the intravascular blood volume remains unchanged and insensible perspiration is negligible, the fluid must accumulate inside the body. This concept brings into question common liberal infusion regimens. Blood volume after fasting is normal, and a fluid-consuming third space has never been reliably shown. Crystalloids physiologically load the interstitial space, whereas colloidal volume loading deteriorates a vital part of the vascular barrier. The endothelial glycocalyx plays a key role and is destroyed not only by ischemia and surgery, but also by acute hypervolemia. Therefore, undifferentiated fluid handling may increase the shift toward the interstitial space. Using the right kind of fluid in appropriate amounts at the right time might improve patient outcome.
Permalink
20 Oct 09
Posted in Anesthesia, Pre-operatie evaluation at 12:18 by Laci
By M London
Anesthesiology 2009;111:690-694
Attempting to articulate his thoughts on the legal definition of obscenity in the 1960s, Supreme Court Justice Potter Stewart, opined I know it when I see it. This approach, celebrated at that time as intuitive and pragmatic, was one he later recanted. Clinicians take a similar approach to situations that are often more complex than they appear. In this issue of Anesthesiology, van Klei et al. report an analysis of patterns of perioperative β-blocker prescription in patients undergoing orthopedic surgery.1 They conclude that their results provide confirmatory evidence to one of the two class 1 recommendations for perioperative β-blockade of the American College of Cardiology/American Heart Association Perioperative Evaluation Guidelines Committee, paraphrased by the authors as not to withdraw β-blocker therapy. As the current guideline comprise only a single paragraph with three literature citations, a closer look at this issue appears timely.
Permalink