12 Apr 09
Posted in Coronary artery disease at 0:28 by Laci
By P Michael Ho,T M Maddox, L Wang, S D Fihn, R L Jesse, E D Peterson, J S Rumsfeld
JAMA. 2009;301:937-944
Prior mechanistic studies reported that omeprazole decreases the platelet inhibitory effects of clopidogrel, yet the clinical significance of these findings is not clear.
Objective
To assess outcomes of patients taking clopidogrel with or without a proton pump inhibitor (PPI) after hospitalization for acute coronary syndrome (ACS).
Design, setting, and patients
Retrospective cohort study of 8205 patients with ACS taking clopidogrel after discharge from 127 Veterans Affairs hospitals between October 1, 2003, and January 31, 2006. Vital status information was available for all patients through September 30, 2006.
Main outcome measures
All-cause mortality or rehospitalization for ACS.
Results
Of 8205 patients taking clopidogrel after discharge, 63.9% (n = 5244) were prescribed PPI at discharge, during follow-up, or both and 36.1% (n = 2961) were not prescribed PPI. Death or rehospitalization for ACS occurred in 20.8% (n = 615) of patients taking clopidogrel without PPI and 29.8% (n = 1561) of patients taking clopidogrel plus PPI. In multivariable analyses, use of clopidogrel plus PPI was associated with an increased risk of death or rehospitalization for ACS compared with use of clopidogrel without PPI (adjusted odds ratio [AOR], 1.25; 95% confidence interval [CI], 1.11-1.41). Among patients taking clopidogrel after hospital discharge and prescribed PPI at any point during follow-up (n = 5244), periods of use of clopidogrel plus PPI (compared with periods of use of clopidogrel without PPI) were associated with a higher risk of death or rehospitalization for ACS (adjusted hazard ratio, 1.27; 95% CI, 1.10-1.46). In analyses of secondary outcomes, patients taking clopidogrel plus PPI had a higher risk of hospitalizations for recurrent ACS compared with patients taking clopidogrel without PPI (14.6% vs 6.9%; AOR, 1.86 [95% CI, 1.57-2.20]) and revascularization procedures (15.5% vs 11.9%; AOR, 1.49 [95% CI, 1.30-1.71]), but not for all-cause mortality (19.9% vs 16.6%; AOR, 0.91 [95% CI, 0.80-1.05]). The association between use of clopidogrel plus PPI and increased risk of adverse outcomes also was consistent using a nested case-control study design (AOR, 1.32; 95% CI, 1.14-1.54). In addition, use of PPI without clopidogrel was not associated with death or rehospitalization for ACS among patients not taking clopidogrel after hospital discharge (n = 6450) (AOR, 0.98; 95% CI, 0.85-1.13).
Conclusion
Concomitant use of clopidogrel and PPI after hospital discharge for ACS was associated with an increased risk of adverse outcomes than use of clopidogrel without PPI, suggesting that use of PPI may be associated with attenuation of benefits of clopidogrel after ACS.
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07 Apr 09
Posted in Fluid management at 7:00 by Laci
By M Jacob, D Chappall, P Conzen, U Finsterer, M Rehm
Acta Anaesthesiol Scand 2008; 52: 522–29
Pre-operative fasting is assumed to cause a deficit in intravascular blood volume (BV), as a result of ongoing urine production and insensible perspiration. Standard regimes consist of volume loading prior or simultaneous to any anaesthetic procedure to minimise the risk of hypotension. However, fluid overload in the context of major abdominal surgery has been shown to deteriorate patient outcome. Our study aimed to quantify total intravascular BV after fasting by direct measurements and to compare it with calculated normal values in comparable non-fasted patients.
Methods
After 10 h of fasting, total plasma volume (PV) and red cell volume (RCV) were measured via the double-label technique (indocyanine green dilution and erythrocytes labelled with fluorescein, respectively) following induction of general anaesthesia in 53 gynaecological patients suffering from malignoma of the cervix. The corresponding normal values were calculated individually from age, body height and body weight.
Results
Measured BV, RCV and PV after fasting were 4123±589, 1244±196 and 2879±496 ml, respectively. The differences to the corresponding calculated normal values were not significant (3882±366, 1474±134 and 2413±232 ml, respectively). The measured haematocrit reflected a slight anaemic state (0.35±0.03).
Conclusion
Our data suggest that even after prolonged pre-operative fasting, cardio-pulmonary healthy patients remain intravascularly normovolaemic. Therefore, hypotension associated with induction of general or neuraxial anaesthesia should perhaps be treated with moderate doses of vasopressors rather than with undifferentiated volume loading
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05 Apr 09
Posted in Inotropic support, Sepsis at 15:31 by Laci
By M Ruggiero
AACN Advanced Critical Care 2008;19:281-287
Septic shock continues to be one of the leading causes of death in the intensive care unit today. The confluence of many factors contributes to the deterioration of patients’ condition in septic shock. Increased levels of nitric oxide, in part, mediate the cardiovascular effects of septic shock. Nitric oxide is major mediator of vasodilation and hypotension as well as myocardial depression. It also contributes to decreased production and release of endogenous vasopressin. Vasopressin effects are actualized by stimulation …
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Posted in Fluid management at 7:24 by Laci
T Borup, R G Hahn, K Holte, L Ravn and H Kehlet
Acta Anaesthesiol Scand 2009;108:311-317
It is unknown whether an intra-operative colloid infusion alters the dynamics of a crystalloid load administered post-operatively.
Methods
Ten patients received 12.5 ml/kg of Ringer’s lactate over 30 min 1–3 days before and 4 h after laparoscopic cholecystectomy, during which 10 ml/kg of a colloid solution, hydroxyethylstarch (HES 130/0.4), was infused. The total body clearance of the pre- and post-operative test infusions was taken as the ratio between the urinary excretion and the Hb-derived dilution of venous plasma over 150 min. The plasma clearance of the infused fluid was calculated using volume kinetics based on the plasma dilution alone. The pre-operative plasma clearance was compared with the post-operative plasma clearance and patients served as their own control.
Results
The urinary excretion averaged 350 ml for the pre-operative infusion and 612 ml post-operatively, which corresponds to 46% and 68% of the pre- and post-operative infusions, respectively. The total body clearance of the crystalloid fluid was 30 ml/min before surgery and 124 ml/min after surgery (P<0.01). The plasma clearance, as obtained from the plasma dilution alone, was 28 and 412 ml/min, respectively. The maximal increase in plasma volume was 410 ml pre-operatively vs. 220 ml post-operatively.
Conclusions
Infusion of a colloid solution in combination with a crystalloid during laparoscopic cholecystectomy increased the plasma clearance of a post-operative crystalloid infusion.
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