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Item Open Access Therapeutic drug monitoring for continuous infusion of vancomycin in critically ill patients(University of the Free State, 2011) Van den Heever, T.; Spruyt, M. G. L.English: Introduction Studies on therapeutic drug monitoring for continuous infusion of vancomycin in critically ill patients are scant. It has been proven that therapeutic levels of 15 – 20 mg/L is effective in treating severe gram positive infections and if kept in this range the amount of drug entering in and out of the tissue are equal. A loading dose of 15mg/kg should be administered irrespective of the renal function. The maintenance infusion in non renal impaired patients should be 30mg/kg and adjusted on a daily basis according levels. This study was over a short period of time and no nephrotoxicity was detected. Methods A prospective analytical study of 10 consecutive patients meeting the inclusion criteria, admitted to the Multidisciplinary Intensive Care Unit at Universitas Hospital was applied. Results were summarised by means of standard deviations or percentiles (numerical variables), frequencies and percentages (categorical variables). The distribution volume was used to calculate the estimated dosage of vancomycin to be given in order to achieve a therapeutic plasma concentration, in the case of vancomycin 15 – 20 mg/L. A loading does of 15mg/kg in 200ml 5% dextrose water over a 2 hour period was administered. Immediately after the loading dose a constant infusion of 30mg/kg in 200ml 5% dextrose water was started at a rate of 8ml/hr ivi. Results Of the thirteen patients only ten met the inclusion criteria. After the loading dose the mean concentration was 34,9 mg/L. The mean concentration after the first, second and third time interval was between 15 – 20 mg/L. The mean time to reach therapeutic levels of 15 – 20 mg/L was 21 hours. A mean elimination constant of 0.150 was shown to be the most effective in obtaining therapeutic levels whilst on a constant vancomycin infusion. If the elimination constant was more than 0.150 then the maintenance dosage had to be reduced and vice versa. The mean total Vancomycin administered to reach therapeutic levels was 3 282mg. Aim To test a feasible regimen for adjusting maintenance of vancomycin infusion in the critically ill patient in order to reach therapeutic vancomycin levels (15 – 20 mg/L) after commencement. Conclusion To optimise treatment of the critically ill patient institution-specific protocols need to be instituted. For vancomycin, a loading dose of 15mg/kg and a continuous infusion of 30mg/kg in 200ml 5% dextrose water are advisable to keep the concentration 15 – 20 mg/L. A distribution volume of 0,72 l/kg should be used for patients with a creatinine clearance above 60 ml/min. For patients with impaired renal function different distribution volumes are advisable. If the creatinine clearance is between 10 – 60 ml/min then a distribution volume of 0.89 l/kg is advisable. If the creatinine clearance is less than 10 ml/min then a distribution volume of 0.9 l/kg is advisable. These distribution volumes should be used to adjust the maintenance infusion accordingly. This study shows that with known pharmacodynamic and pharmacokinetic parameters it is possible to maintain a steady state with a continuous vancomycin infusion. This would lead to more time- and cost- effective treatment for patients with Vancomycin sensitive organisms.Item Open Access The predictive ability of the Acute Physiology and Chronic Health Evaluation (APACHE II) score for mortality in the Intensive Care Unit in Kimberley hospital(University of the Free State, 2007) Krog, Colleen; Van der Berg, P. S.Introduction: The aim of this study was to assess the Acute Physiology and Chronic Health Evaluation (APACHE II) prognostic index in the Intensive Care Unit of Kimberley Hospital Complex (KHC) on admission. The study was more specifically aimed at patients meeting criteria for the Systemic Inflammatory Response Syndrome (SIRS), as patients admitted to KHC ICU frequently meet the criteria and often progress to sepsis, severe sepsis and septic shock. Design: A cohort study on South African patients meeting SIRS criteria, including all races and gender. Setting: Intensive Care Unit of Kimberley Hospital Complex, provincial hospital in the Northern Cape province, South Africa. Patients and measurements: Consecutive patients meeting the criteria for SIRS on admission to ICU between August 2006 and May 2007 were included. For each patient the diagnosis, physiological and chronic health data necessary for the APACHE score was gathered and recorded by the doctor on duty on time of admission. Predicted and actual mortality rates were calculated. Data was provided to the department of Biostatistics of the UFS for processing. Results were summarised by means, standard variations and percentiles (numerical variables) and frequencies and percentages (categorical variables). Results Of the 160 patients included in the study, 59 died (36.9%). Patients discharged from the unit before 14 days were followed up in the ward until 14 days or discharge from hospital (whichever came first). 77 patients were discharged from ICU within 14 days of which 3 (1.9%) died in the ward within the 14-day period. 74 of the discharged patients (46.3%) were alive after 14 days. 24 patients (14%) participating in the trial were still in ICU after 14 days and mortality not recorded. The counting of patients who survived and those who died, for each level of death risk predicted, allowed the calculation of sensitivity, specificity and the percentage of correct predictions for each level of predicted death risk. The sensitivity of the calculated death risk was higher at scores below 8, gradually decreasing as scores increased, reaching 50.9% at score >21. Conversely the specificity increased from 1% for scores <5, reaching 79.2% for death risk at scores >21. The most accurate combination of sensitivity and specificity was found at scores of 16-18, with the positive prediction value ranging from 51.3-54.4% and the negative prediction value ranging from 76.1-77.5%. There was a meaningful connection between APACHE II scores and the mortality rate, for all patients and each diagnostic group. In each successive APACHE II score interval the mortality rate was higher than that of the preceding interval. Thus, the result has confirmed the capability of this index to stratify such patients according to the degree of severity of their health condition. Conclusion The APACHE II scoring system may be usefully applied in Intensive Care Units for predicting mortality, classifying and assessing severity of disease and evaluating performance. It must however be used with caution for planning department resource allocation and decision making regarding admission of patients to Intensive Care.