13 Jan 08
Posted in Infection, Procalcitonin at 17:50 by Laci
By R Zazula, M Prucha, T Tyll and E Kieslichova
Critical Care 2007,11
The aim of this study was to compare the early postoperative kinetics of procalcitonin (PCT) and C-reactive protein (CRP) serum levels in patients undergoing orthotopic liver transplantation (OLTx) with different immunosuppressive regimens.
Methods
PCT and CRP serum concentrations were measured in a group of 28 OLTx recipients before induction of anesthesia, at 4 and 8 hours following graft reperfusion, and daily until postoperative day 4. The same parameters were determined in 12 patients undergoing liver resection without conjunctive immunosuppressive therapy. Summary data are expressed as medians and ranges. Two-tailed nonparametric tests were performed and considered significant at p values of less than 0.05.
Results
The highest serum levels of PCT (median 3.0 ng/mL, minimum 1.4 ng/mL, maximum 13.9 ng/mL) were found in patients after OLTx without ATG therapy, on postoperative day 1. In patients with ATG administration, PCT levels were highly increased on postoperative day 1 (median 53.0 ng/mL, minimum 7.9 ng/mL, maximum 249.1 ng/mL). Thereafter, PCT values continuously decreased independently of further ATG administration in both groups of patients. No evidence of infection was present in either group. In 12 patients undergoing liver resection, peak serum PCT levels did not exceed 3.6 ng/mL. CRP serum levels in a group of patients with and without ATG therapy increased significantly on postoperative day 1, followed by a decrease. The highest levels of CRP were found in patients after liver resection on postoperative day 2 and decreased thereafter.
Conclusion
ATG administration to patients with OLTx is associated with an increase in serum PCT levels, with peak values on postoperative day 1, and this was in the absence of any evidence of infection. The results of this study indicate that ATG immunosuppressive therapy is a stimulus for the synthesis of PCT.
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Posted in Acid-Base disorders at 17:46 by Laci
By D Bruegger, GI Kemming, M Jacob, FG Meisner, C J Wojtczyk, KB Packert et al
Critical Care 2007, 11:R130
Metabolic acidosis during hemorrhagic shock is common and conventionally considered to be due to hyperlactatemia. There is increasing awareness, however, that other nonlactate, unmeasured anions contribute to this type of acidosis.
Methods
Eleven anesthetized dogs were hemorrhaged to a mean arterial pressure of 45 mm Hg and were kept at this level until a metabolic oxygen debt of 120 mLO2/kg body weight had evolved. Blood pH, partial pressure of carbon dioxide, and concentrations of sodium, potassium, magnesium, calcium, chloride, lactate, albumin, and phosphate were measured at baseline, in shock, and during 3 hours post-therapy. Strong ion difference and the amount of weak plasma acid were calculated. To detect the presence of unmeasured anions, anion gap and strong ion gap were determined. Capillary electrophoresis was used to identify potential contributors to unmeasured anions.
Results
During induction of shock, pH decreased significantly from 7.41 to 7.19. The transient increase in lactate concentration from 1.5 to 5.5 mEq/L during shock was not sufficient to explain the transient increases in anion gap (+11.0 mEq/L) and strong ion gap (+7.1 mEq/L), suggesting that substantial amounts of unmeasured anions must have been generated. Capillary electrophoresis revealed increases in serum concentration of acetate (2.2 mEq/L), citrate (2.2 mEq/L), α-ketoglutarate (35.3 μEq/L), fumarate (6.2 μEq/L), sulfate (0.1 mEq/L), and urate (55.9 μEq/L) after shock induction.
Conclusion
Large amounts of unmeasured anions were generated after hemorrhage in this highly standardized model of hemorrhagic shock. Capillary electrophoresis suggested that the hitherto unmeasured anions citrate and acetate, but not sulfate, contributed significantly to the changes in strong ion gap associated with induction of shock.
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12 Jan 08
Posted in Acid-Base disorders at 12:59 by Laci
By D A Story, H Morimatsu and R Bellomo
BJA 2004;92:54-60
The Fencl-Stewart approach to acid-base disorders uses five equations of varying complexity to estimate the base excess effects of the important components: the strong ion difference (sodium and chloride), the total weak acid concentration (albumin) and unmeasured ions. Although this approach is straightforward, most people would need a calculator to use the equations. We proposed four simpler equations that require only mental arithmetic and tested the hypothesis that these simpler equations would have good agreement with more complex Fencl-Stewart equations.
Methods
We reduced two complex equations for the sodium±chloride effect on base excess to one simple equation: sodium±chloride effect (meq litre-1)=[Na+]-[Cl-]-38. We simplified the equation of the albumin effect on base excess to an equation with two constants: albumin effect (meq litre-1)=0.25x(42-[albumin]g litre-1). Using 300 blood samples from critically ill patients, we examined the agreement between the more complex Fencl-Stewart equations and our simplified versions with Bland-Altman analyses.
Results
The estimates of the sodium-chloride effect on base excess agreed well, with no bias and limits of agreement of -0.5 to 0.5 meq litre-1. The albumin effect estimates required log transformation. The simpliÆed estimate was, on average, 90% of the Fencl±Stewart estimate. The limits of agreement for this percentage were 82-98%.
Conclusions
The simplified equations agree well with the previous, more complex equations.Our findings suggest a useful, simple way to use the Fencl-Stewart approach to analyse acid-base disorders in clinical practice.
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Posted in Infection at 12:53 by Laci
By S Florman and R L Nichols
Am J Infect Dis. 2007;3:51-61
Surgical site infections (SSIs) are the most common type of nosocomial infection among surgical patients and are commonly caused by the patients own microbial flora. The prevalence of SSI is a major concern because of the associated increase in the incidence of morbidity and mortality, length of hospitalization and cost of care for postoperative patients. Key factors that determine whether patients are at risk for developing SSI include the inherent potential contamination of the surgical site, the duration of the operation and the individual patient susceptibility. Preventive preoperative measures that can reduce the risk of SSIs include administration of antimicrobial prophylaxis, proper utilization of skin antiseptic agents for both the patient and the surgical team, proper patient preoperative hair removal and the policy of canceling elective procedures when remote skin, urinary or pulmonary infections occur. This paper will review the efficacy and safety of available antiseptic agents, as well as discuss patient-specific prevention strategies.
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