[Quality assurance concepts in intensive care medicine]

Intensive care medicine (ICM) is characterized by a high degree of complexity and requires intense communication and collaboration on interdisciplinary and multiprofessional levels. In order to achieve good quality of care in this environment and to prevent errors, a proactive quality and error management as well as a structured quality assurance system are essential. Since the early 1990s, German intensive care societies have developed concepts for quality management and assurance in ICM. In 2006, intensive care networks were founded in different states to support the implementation of evidence-based knowledge into clinical routine and to improve medical outcome, efficacy, and efficiency in ICM. Current instruments and concepts of quality assurance in German ICM include core intensive care data from the data registry DIVI REVERSI, quality indicators, peer review in intensive care, IQM peer review, and various certification processes. The first version of German ICM quality indicators was published in 2010 by an interdisciplinary and interprofessional expert commission. Key figures, indicators, and national benchmarks are intended to describe the quality of structures, processes, and outcomes in intensive care. Many of the quality assurance tools have proved to be useful in clinical practice, but nationwide implementation still can be improved.

Feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients

Monoplane hemodynamic TEE (hTEE) monitoring (ImaCor(®) ClariTEE(®)) might be a useful alternative to continuously evaluate cardiovascular function and we aimed to investigate the feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients. After IRB approval we reviewed the electronic data of cardiac surgery patients admitted to our intensive care between 01/01/2012 and 30/06/2013 in a case-controlled matched-pairs design. Patients were eligible for the study when they presented a sustained hemodynamic instability postoperatively with the clinical need of an extended hemodynamic monitoring: (a) hTEE (hTEE group, n = 18), or (b) transpulmonary thermodilution (control group, n = 18). hTEE was performed by ICU residents after receiving an approximately 6-h hTEE training session. For hTEE guided hemodynamic optimization an institutional algorithm was used. The hTEE probe was blindly inserted at the first attempt in all patients and image quality was at least judged to be adequate. The frequency of hemodynamic examinations was higher (ten complete hTEE examinations every 2.6 h) in contrast to the control group (one examination every 8 h). hTEE findings, including five unexpected right heart failure and one pericardial tamponade, led to a change of current therapy in 89% of patients. The cumulative dose of epinephrine was significantly reduced (p = 0.034) and levosimendan administration was significantly increased (p = 0.047) in the hTEE group. hTEE was non-inferior to the control group in guiding norepinephrine treatment (p = 0.038). hTEE monitoring performed by ICU residents was feasible and beneficially influenced the postoperative management of cardiac surgery patients.

Breed-specific hematologic reference intervals in healthy adult Dogues de Bordeaux

BACKGROUND

There is an increasing interest for breed-specific reference intervals in veterinary medicine. In a previous study, breed-specific biochemical reference intervals (RIs) have been established for Dogues de Bordeaux (DDBs). This breed is predisposed to familial juvenile glomerulonephropathy and hypothyroidism, and would benefit from hematologic RI.

OBJECTIVE

The purpose was de novo establishment of breed-specific hematologic RIs for the DDB in accordance with the International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines.

METHODS

One hundred and twenty DDBs from France and Belgium were recruited. CBCs were determined with the Sysmex XT-2000iV analyzer within 12 hours of blood collection. RIs were determined using the nonparametric method. Effects of sex, age, and face mask color were studied.

RESULTS

RIs were determined in 58 healthy dogs. DDBs had higher RIs for HGB, HCT, MCV, MCHC, and mean platelet volume, and lower RIs for reticulocytes counts, platelets by impedance (PLT-I) and optical count (PLT-O), and plateletcrit when compared with generic canine RIs. Age significantly affected RIs for HGB, HCT, MCHC, WBC, neutrophil, lymphocyte, and monocyte counts.

CONCLUSION

The generic canine RIs established in the same laboratory with analogous preanalytical and analytical variations did not differ significantly from breed-specific RIs, and thus have no significant impact on clinical decision making; however, breed-specific RIs are advised for some RBC and all platelet-related variables to avoid erroneous suspicion of polycythemia and thrombocytopenia when using general canine RIs for evaluation of DDB.

Hematologic reference intervals in Cynomolgus (Macaca fascicularis) monkeys

BACKGROUND

Reference intervals are important aids for interpreting clinical pathology laboratory data especially in Cynomolgus monkey (Macaca fascicularis), the non-human primate species most widely used in biomedical research. The purpose of this study was to establish hematologic reference intervals for Cynomolgus according to the International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines using the databank at a primatology center.

METHODS

Blood specimens from 272 healthy Cynomolgus imported from Mauritius, the Philippines and Vietnam, were analyzed. Reference intervals were established by nonparametric method. Effects of sex, age, body weight, and breeding origin were investigated.

RESULTS

Hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration decreased slightly and mean corpuscular volume increased slightly with age. Lower red blood cell concentration, hemoglobin, and hematocrit were observed in monkeys from the Philippines.

CONCLUSIONS

These hematology reference intervals, established according to international recommendations, can be used in settings using similar animals and analyzers.

Breed-specific biochemical reference intervals for the adult Dogue de Bordeaux

BACKGROUND

Breed-specific reference intervals are of increasing interest in veterinary medicine. The health monitoring of the Dogue de Bordeaux, a breed predisposed to familial juvenile glomerulonephropathy and hypothyroidism, would benefit from specific reference intervals.

OBJECTIVE

The purpose of this study was to establish breed-specific biochemical reference intervals for the Dogue de Bordeaux in accordance with the International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines.

METHODS

One hundred and twenty Dogues de Bordeaux from France and Belgium were recruited. Complete urinalysis and chemistry panels, venous blood gas variables, total thyroxin and thyroid stimulating hormone, and fibrinogen and antithrombin were measured for each dog. Reference intervals were determined using the non-parametric method. Confounding variables such as sex, age and color of facial mask were analyzed.

RESULTS

Due to pre-defined criteria for exclusion, 62 healthy dogs were finally selected for the reference intervals determination. Using the instrument manufacturer's generic canine RI for most analytes did not have a significant impact on potential clinical decisions, except for total proteins, ALT, AST, total cholesterol, lipase and total thyroxin, for which possible clinically relevant differences were noted.

CONCLUSION

Specific reference intervals for biochemical analytes in the Dogue de Bordeaux were determined under controlled pre-analytical and analytical conditions, and according to international recommendations. The use of these breed-specific reference intervals is recommended when using the specified analytic instruments, especially for the 6 analytes for which the reference intervals differed considerably from those provided by manufacturers.

A new approach for the determination of reference intervals from hospital-based data

BACKGROUND

Reference limits are some of the most widely used tools in the medical decision process. Their determination is long, difficult, and expensive, mainly because of the need to select sufficient numbers of reference individuals according to well-defined criteria. Data from hospitalized patients are, in contrast, numerous and easily available. Even if all the information required for a direct reference interval computation is usually not available, these data contain information that can be exploited to derive at least rough reference intervals.

METHODS

In this article, we propose a method for the indirect estimation of reference intervals. It relies on a statistical method which has become a gold-standard in other sciences to separate components of mixtures. It relies on some distributional assumptions that can be checked graphically. For the determination of reference intervals, this new method is intended to separate the healthy and diseased distributions of the measured analyte. We assessed its performance by using simulated data drawn from known distributions and two previously published datasets (from human and veterinary clinical chemistry).

RESULTS AND DISCUSSION

The comparison of results obtained by the new method with the theoretical data of the simulation and determination of the reference interval for the datasets was good, thus supporting the application of this method for a rough estimation of reference intervals when the recommended procedure cannot be used.

Comparison of measurements of canine plasma glucose, creatinine, urea, total proteins, alanine aminotransferase, and alkaline phosphatase obtained with the APOLOWAKO and Vitros 250 analyzers

The APOLOWAKO is an entirely automatic benchtop biochemistry analyzer that uses stabilized liquid reagents. It was tested for canine blood and plasma glucose, creatinine, urea, total proteins, alanine aminotransferase, and alkaline phosphatase. The APOLOWAKO gave very similar results for whole blood and the corresponding plasma (n=32). Within-laboratory imprecision was below 2.2% and 5.8% for substrates and enzymes, respectively. Comparison of results with whole blood by APOLOWAKO and with the corresponding plasma by Vitros 250 (n=139) showed very good correlations. Passing-Bablok's regression slopes ranged from 0.83 to 1.12 and intercepts were close to zero, except for ALP where the results obtained by APOLOWAKO were approximately 1.5 times higher than by Vitros. The APOLOWAKO system can be a reliable instrument in veterinary practices where larger systems are not available but it should be further validated and reference intervals should be determined.

[Analysis of personnel costs after reorganization of intensive care using calculated diagnosis-related groups comparative data. An investigation at the Charité Berlin]

BACKGROUND

In an extensive project intensive care units (ICUs) of the Charité University Hospital were reorganized. The aim of this investigation was to determine if staff costs after this reorganization are financed by modular profits of diagnosis-related groups (DRGs).

METHODS

Staff costs of all non-pediatric intensive care units, including ICUs, intermediate care units and post-anaesthesia care units (PACUs) in the Charité University Hospital were compared with the modular profits of all DRGs of patients older than 14 years in 2005. These DRGs were converted into the German refined DRG (GDRG) system 4.0 from 2006 with calculations based on actual income for medical doctors and nurses in 2006. Due to changed wage agreements for the incomes of physicians in 2006 there was an increase of costs. For the other professional groups an increase in income is expected, which cannot be estimated at present.

RESULTS

The calculation revealed that staff costs of the ICUs at the Charité University Hospital based on a current German mean base rate of 2,836 EUR were 4.2% above the modular profits of the DRGs. As a result of a structural reorganization of the ICUs, the costs of staff could be adapted to the modular profits. Under the conditions of the actual reduced base rate of Berlin of 2,955 EUR the costs and profits were nearly equal. As the financial impact of the reorganization of the ICUs will take full effect in the coming years, it can be anticipated that with an expected base rate of 2,949 EUR in 2010 the intensive care medicine of a University hospital in Germany can become profitable.

DISCUSSION

The spectrum of intensive care medicine at the Charité University Hospital covers the maximum range of operative and non-operative medicine. After an extensive reorganization of the ICUs under the aspect of staff costs, intensive care medicine can become profitable under the 4.0 G-DRG system. With consequent reorganization the cost efficiency of staff can be optimized, particularly in the setting of high-end intensive care medicine.

Barrier function of the gut and multiple organ dysfunction after cardiac surgery

We studied the influence of sequential involvement of the gastrointestinal (GI) tract on the development of multiple organ dysfunction (MOD) after cardiopulmonary bypass (CPB). One hundred and forty-six patients undergoing elective cardiac surgery were included in this prospective observational study. Standardized oral inert-sugar tests (sucrose, lactulose, mannitol, sucralose) were performed before and after CPB in different patients. Enzyme-linked immunosorbent assay of plasma levels of endotoxin core antibodies (EndoCAb) were performed peri-operatively. The functional mucosal surface was calculated from the amount of mannitol absorbed from the GI tract. Lower urine concentrations of absorbed mannitol were observed pre-operatively in patients developing MOD. In binary logistic regression this was an independent parameter. Decreased plasma concentrations of EndoCAb after surgery were seen in every patient, but were more significant in patients developing MOD. A reduced pre-operative functional mucosal surface may predict the early occurrence of MOD after surgery.

Stability of selected hematology variables in canine blood kept at room temperature in EDTA for 24 and 48 hours

BACKGROUND

Most hematologic analyses are performed within a short time of blood sampling, but samples collected at the end of a week may have to be stored for up to 2 days. The stability of hematologic constituents is poorly documented.

OBJECTIVE

The objective of this study was to compare the results of RBC, WBC and platelet counts, hemoglobin (Hgb) concentration, and MCV before and after storage of canine blood at room temperature for 24 and 48 hours.

METHODS

One hundred fifty-two K3-EDTA canine blood specimens from 2 veterinary hospitals were analyzed within 4 hours of collection, then 24 and 48 hours later with a Coulter T540 hematology analyzer. Results were compared by Passing-Bablock agreement, difference plots, and according to their classification as normal or abnormal based on reference intervals.

RESULTS

RBC count and Hgb concentration were stable for the duration of the study. Differences in WBC and platelet counts varied with the specimen, independently of the initial value. MCV increased consistently over the 2 days. However, only a few results were misclassified.

CONCLUSION

Whole blood specimens stored for up to 2 days at room temperature are suitable for cell counts and Hgb measurement. However, potential variations have to be known to avoid misinterpretations, especially near the decision limits.

Simultaneous and minimally invasive assessment of muscle tolerance and bioavailability of different volumes of an intramuscular formulation in the same animals1

Evaluation of skeletal muscle tolerance during development of new drug formulations for i.m. use is most often based on terminal methods performed in the target species after slaughtering. The objective of this study was to evaluate the effect of muscle damage on the pharmacokinetic parameters of the drug delivered into the muscle using an alternative, noninvasive method. Phenylbutazone (PBZ) was used as the test article. Six ewes received increasing volumes of a 20% PBZ i.m. formulation, according to a cross-over design, and an i.v. bolus of the same formulation. Serial blood samples were taken, and a pharmacokinetic analysis of the plasma activity of creatine kinase and plasma PBZ concentrations was carried out. The amount of muscle damage after i.m. administration of 2, 4, or 8 mL of PBZ, calculated from the area under the curve of plasma creatine kinase across time was 36, 76, and 178 g for a 70-kg ewe. The corresponding absolute bioavailability of PBZ was 100 +/- 32%, 96 +/- 19%, and 100 +/- 17%, and the maximal PBZ concentrations were 42 +/- 3.4, 74 +/- 8.8, and 119 +/- 18.2 microg/mL. The plasma clearance of PBZ (i.v.) was 4.2 +/- 0.94 mL.kg(-1).h(-1). In conclusion, the absolute bioavailability of PBZ after i.m. administration was not altered by the increased volume of formulation administered despite the overall increase in the extent of muscle damage.

Adverse Haematological Effects of Vinblastine, Prednisolone and Cimetidine Treatment: a Retrospective Study in Fourteen Dogs with Mast Cell Tumours

Vinblastine toxicity is poorly documented in dogs. The aim of this study was to investigate the haematological alterations in dogs treated with vinblastine and prednisolone. Fourteen dogs with mast cell tumours (MCT) were selected on at least one of the following criteria: lymph node infiltration, surgical margin infiltration, grade II MCTs with Ki-67 >10%, and grade III MCTs. Starting 15 days after surgery, the dogs were given vinblastine (2 mg/m2 i.v. four times weekly, then twice monthly for 2 months) and prednisolone (2 mg/kg/day p.o.). An EDTA blood sample was collected weekly for complete blood count (CBC). A total of 98 doses of vinblastine were given to the 14 dogs and 114 CBC were performed. Abnormal haematological findings were observed in 12 CBCs from five dogs, which represent a prevalence of 20% of the total CBCs performed in these animals. The most prevalent abnormal finding was thrombopenia (9/12) most often with grade I toxicity (6/9). In conclusion, the risk of occurrence of adverse haematological effects resulting from vinblastine-prednisolone treatment seems limited in dogs with MCT and it should not be overestimated.

Comparison of measurements of canine plasma creatinine, glucose, proteins, urea, alanine aminotransferase, and alkaline phosphatase obtained with Spotchem SP 4430 and Vitros 250 analyzers

The suitability of the Spotchem 4430 benchtop biochemistry analyzer for canine blood samples was tested for creatinine, glucose, proteins, urea, alkaline phosphatases and alanine aminotransferase. Results obtained from whole blood and corresponding heparin plasma were identical except for proteins which were higher in plasma (n=10). Between series imprecision (n=10) was <5% for substrates and <10% for enzymes. Comparison of results from 100 Li-heparin samples with those measured with a Vitros 250 analyzer showed good correlation (r>0.93). The slopes of the Passing-Bablock's regression ranged from 0.90 to 1.20 and intercepts were low. The mean biases were low, except for creatinine for which the results obtained by Spotchem (Jaffe reaction) were about 20 micromol/L higher than with the Vitros (enzymatic reaction). The results of this study show that the Spotchem analyzer is suitable for use in canine whole blood or plasma when small numbers of tests are to be performed and large analyzers are not available.

Comparison of plasma/serum urea and creatinine concentrations in the dog: a 5-year retrospective study in a commercial veterinary clinical pathology laboratory

Serum/plasma urea (S/P-urea) and creatinine (S/P-creatinine) concentrations are routinely assayed as indirect markers of glomerular filtration rate and have been reported to be highly correlated. The aim of this study was to evaluate the relationship between the two analytes in a large number of unselected samples submitted to a commercial laboratory. In 4799 pairs of results, the correlation was high (r = 0.795) and was not affected by sex or age. The relationship between the two analytes was best represented by a second-order polynomial equation. However, the dispersion of results was large and there was a high percentage of cases (27.5%) where S/P-urea was increased and S/P-creatinine normal (< or =120 micromol/l for this laboratory), while there was a low percentage of cases where S/P-creatinine (1.6%) was increased and S/P-urea normal (< or =8 mmol/l for this laboratory). The discrepancy between increases in S/P-urea and S/P-creatinine might not only reflect a high incidence of non-renal factors of variation for S/P-urea but also an effect of the size or muscle mass of the dogs on the limit of decision for S/P-creatinine. In dogs with normal S/P-urea, there was a significant effect of the size on the 0.975 quantile of S/P-creatinine, ranging from 106 micromol/l in very small dogs to 133 micromol/l in large and very large dogs. This study shows that isolated increases in S/P-urea could be misleading for the diagnosis of renal diseases and that the reference intervals of S/P-creatinine should be re-evaluated according to breed or muscle mass of dogs.

Splanchnic oxygen transport, hepatic function and gastrointestinal barrier after normothermic cardiopulmonary bypass

BACKGROUND

The effect of non-pulsatile, normothermic cardiopulmonary-bypass (CPB) on the splanchnic blood-flow and oxygen-transport, the hepatic function and the gastrointestinal barrier were observed in a prospective observational study in 31 adults undergoing cardiac valve replacement surgery.

METHODS

The splanchnic (i.e. hepatic) blood-flow (HBF) was measured by the constant infusion of indocyanine-green (ICG) using a hepatic-venous catheter. Liver function was examined by calculation of lactate uptake, ICG extraction and the monoethylglycinexylidide (MEGX) test. A day before and after surgery the gastrioduodenal and intestinal permeability was measured by determination of sucrose and lactulose/mannitol excretion.

RESULTS

Splanchnic blood flow and oxygen delivery did not decrease during and after surgery while splanchnic oxygen consumption (P < 0.0125) and arterial lactate concentrations increased. The splanchnic lactate uptake paralleled the lactate concentration. After but not during CPB an increase of systemic oxygen consumption was observed. The MEGX test values decreased on the first day after surgery. The ICG extraction was attenuated during the operation. The gastroduodenal and the intestinal permeability increased significantly postoperatively (P < 0.002, respectively, P < 0.001). There was no correlation between these findings and the duration of CPB. There was a significant correlation of the intestinal permeability but not of the gastroduodenal permeability between the prior and after surgery values (P < 0.001).

CONCLUSION

Increased oxygen consumption during CPB may indicate an inflammatory reaction due to the pump beginning in the splanchnic area or a redistribution of the splanchinc blood flow during the CPB. Normothermic CPB does not lead to a significant or prolonged reduction of liver function. Normothermic CPB causes an increase of gastrointestinal permeability. The intestinal barrier function prior to surgery was accountable for the degree of loss of intestinal barrier function following surgery.

Comparison of whole blood and plasma potassium concentrations in dogs using the Reflovet system

BACKGROUND

The Reflovet system is designed for chemical analysis of whole blood. However, plasma or serum is recommended for potassium analysis because of possible interference from RBC potassium. Because RBC potassium concentration is low in most canine erythrocytes, however, there should be little or no interference.

OBJECTIVE

The objective of this study was to compare potassium results obtained in whole blood and in plasma from dogs using the Reflovet system.

METHODS

Blood samples were collected from 104 dogs into lithium-heparin tubes. The potassium concentration was measured in whole blood, and subsequently the PCV was measured. Samples were centrifuged and the potassium concentration was measured in plasma. Comparisons were made using Deming's regression and Bland-Altman difference plots.

RESULTS

There was very good correlation between results of potassium measurements in whole blood and plasma (r = 0.93). Potassium values were moderately lower in whole blood: Potassium(blood) = 0.912 x Potassium(plasma)+ 0.119. Hemolysis had a negligible effect on the results, but the difference increased with the PCV value. In more than 90% of samples, the difference between the 2 measurements was <or= 0.3 mmol/L.

CONCLUSION

There is only a negligible difference in most cases between potassium values in canine plasma and whole blood using the Reflovet system.

Creatinine in the Dog: A Review

Creatinine is the analyte most frequently measured in human and veterinary clinical chemistry laboratories as an indirect measure of glomerular filtration rate (GFR). Although creatinine metabolism and the difficulties of creatinine measurement have been reviewed in human medicine, similar reviews are lacking in veterinary medicine. The aim of this review is to summarize information and data about creatinine metabolism, measurement, and diagnostic significance in the dog. Plasma creatinine originates from the degradation of creatine and creatine phosphate, which are present mainly in muscle and in food. Creatinine is cleared by glomerular filtration with negligible renal secretion and extrarenal metabolism, and its clearance is a good estimate of GFR. Plasma and urine creatinine measurements are based on the nonspecific Jaffé reaction or specific enzymatic reactions; lack of assay accuracy precludes proper interlaboratory comparison of results. Preanalytical factors such as age and breed can have an impact on plasma creatinine (P-creatinine) concentration, while many intraindividual factors of variation have little effect. Dehydration and drugs mainly affect P-creatinine concentration in dogs by decreasing GFR. P-creatinine is increased in renal failure, whatever its cause, and correlates with a decrease in GFR according to a curvilinear relationship, such that P-creatinine is insensitive for detecting moderate decreases of GFR or for monitoring progression of GFR in dogs with severely reduced kidney function. Low sensitivity can be obviated by determining endogenous or exogenous clearance rates of creatinine. A technique for determining plasma clearance following IV bolus injection of exogenous creatinine and subsequent serial measurement of P-creatinine does not require urine collection and with additional studies may become an established technique for creatinine clearance in dogs.

Assessment of a pyrogallol red technique for total protein measurement in the cerebrospinal fluid of dogs

The measurement of protein concentration in the cerebrospinal fluid is a basic analytical method in neurology. In this study, a pyrogallol red technique using a human albumin calibrator previously validated in human medicine was tested for canine samples, and the results were compared with those obtained using urine test strips. Pyrogallol red significantly (P<0.05) but moderately underestimated purified dog albumin and globulins. The imprecision of the technique was low: intra- and between-series coefficients of variation were 1.6 and 4.3 per cent at protein concentrations of about 0.3 g/litre. Over 49 samples, there was good agreement between the pyrogallol red and test strip results (r=0.63), especially for low and high protein concentrations, but misclassifications were observed with '+' test strip readings.

Comparison of the techniques of evaluation of urine dilution/concentration in the dog

The objective of this study was to evaluate the quality of the measurement of dog urine dilution/concentration by comparing osmolality with three methods of specific gravity (USG) measurement, i.e. weighing, refractometry and test strips. In unselected urine samples from 182 dogs there was a better agreement between osmolality and USG determination by refractometry (r = 0.92) than by weighing (r = 0.82) or by test strips (r = 0.27). There was an almost linear relationship between osmolality and USG: osmolality (mOsm/kg) = 36646(34318/38974) x (USGref - 1) + 25(-39/88); calculated osmolality differed from measured osmolality by more than 500 mOsm/kg in only 8 of 181 samples. There was a good agreement between USG determination by weighing and refractometry: USGref = 1.000(0.905/1.095) x USGweighing - 0.0004(-0.0019/0.0027), with a moderate bias. Only 12% of the differences between the two methods exceeded 0.010. Test strip assessment of USG was unreliable because of systematic underestimation and should not be used for dog urine. Refractometry is the best technique for routine evaluation of urine concentration/dilution when osmometry is not available.

Measurement of alpha-amylase activity in cat plasma: test of specificity of a chromogenic substrate, reference values

Glucoamylase activity can interfere with the measurement of alpha-amylase activity in cat plasma. This can be avoided by the use of "blocked" substrates such as 4,6-O-benzylidene-4-nitrophenyl-alpha-D-maltoheptaoside. In 241 healthy cats, reference values were 586 +/- 241 U/L (m +/- standard deviation) at 30 degrees C; age, sex, overnight fasting, and mild hemolysis had no significant effect.

The accuracy of the i-STAT portable analyser for measuring blood gases and pH in whole-blood samples from dogs

To assess the suitability of the i-STAT portable analyser for use by non-laboratory personnel, we measured blood gases and pH in venous blood samples from 100 dogs. Deming's regression and bias plots were used to compare i-STAT results with those obtained by laboratory professionals using two different autocalibrated benchtop analysers. Overall accuracy of the portable analyser proved excellent for pH, pO(2), and pCO(2) (r=0.978, 0.968 and 0.997, respectively), with Deming's regression slopes close to 1.00 (0.96, 0.97 and 1.08 for pH, pO(2), and pCO(2), respectively) and intercepts close to zero (0.28, 0.47 kPa and 0.46 kPa for pH, pO(2), and pCO(2), respectively). The accuracy of the i-STAT was also satisfactory for calculated parameters: bicarbonates, total CO(2), base excess and oxygen saturation. Our findings show this portable analyser to be a valid substitute for expensive benchtop analysers in situations requiring mobility, or when small numbers of tests are to be performed by users not specialized in laboratory techniques.

Exercise does not induce major changes in plasma muscle enzymes, creatinine, glucose and total proteins concentrations in untrained beagle dogs

Changes in plasma creatinine (Pl-Creat), glucose, total proteins (Pl-TP), creatine kinase (Pl-CK), lactate dehydrogenase, aspartate aminotransferase and packed cell volume were evaluated in untrained Beagle dogs before, during and after a 60 min race at an average speed of 9 km/h. There was no major effect of exercise on those parameters except, when phases are compared, a slight increase of Pl-TP during exercise (max. + 6.4%), a moderate but after exercise (delayed increase of Pl-CK max. + 245%) and a slight decrease of Pl-Creat after exercise (max. -9.6%). It was therefore concluded that strenuous exercise in sedentary dogs did not induce major variations in any of routine plasma variables measured and would not lead to clinically relevant misinterpretation. However, for Pl-CK, the interpretation of repeated measures may be misleading if two samples are collected in the same animal before and after exercise.

Plasma fibrinogen measurement in the horse: comparison of Millar's technique with a chronometric technique and the QBC-Vet Autoreader

Plasma fibrinogen is widely used in horse practice as an unspecific positive marker of inflammatory diseases; it is also lowered in disseminated intravascular coagulation. Three fibrinogen measurement methods--Millar's heat-denaturation in a microhaematocrit tube, automated reader for heat-denaturation, and chronometric measurement of clot formation after addition of excess thrombin-were compared by means of Passing-Bablock's regression and Bland-Altman difference plots, in blood plasma of 30 clinically healthy and 57 diseased horses. Correlations between the three techniques were excellent (r >0.92). The two heat-denaturation techniques correlated very closely up to 6 g l(-1), above which the results obtained by Millar's technique started to fall below those obtained by the automatic reader. There was proportional bias between Millar's technique and the chronometric technique, with the latter producing results some 30% lower, indicating that reference intervals and decision limits should be adapted accordingly.

Differential effects of phenobarbital on the constitutive and inducible expression of P450 2B and 3A subfamilies in sheep tissues

The activity and expression of cytochromes P450 were determined in liver, kidneys, lungs, duodenum, jejunum, ileum, and caecum of adult Lacaune sheep. High expression of total P450, benzphetamine and erythromycin demethylase activities, and P450 2B isoforms, as two distinct proteins that were detected and called P4502 Bm and P4502 Bx, was found in the lungs (in addition to liver). By contrast, the P450 3A subfamily was only expressed in liver and duodenal mucosa of untreated sheep. Phenobarbital (PB) treatment led to significant increases in all measured hepatic parameters and in total P450 of each investigated organ with the exception of ileum and caecum. Benzphetamine demethylase activity increased in liver and kidneys, correlating with the expression of the two P450 2B proteins, which were also induced in duodenum and ileum. By contrast, benzphetamine demethylase activity and expression of the P450 2B isoforms in lungs were unchanged by PB treatment. Erythromycin demethylation activity and P450 3A subfamily expression was increased only in liver of PB-treated sheep.

Passive containment and reverse remodeling by a novel textile cardiac support device

BACKGROUND

Progressive remodeling and dilation of cardiac chambers is responsible in part for myocardial dysfunction in chronic heart failure. Preclinical studies with suitable animal models indicate that a passive cardiac constraint device can promote reverse remodeling, with improvement in cardiac function. We hypothesize that such a device could provide benefit for stable heart failure patients in New York Heart Association (NYHA) class II and III.

METHODS AND RESULTS

From April 1999 to March 2000, 27 patients received Acorn's Cardiac Support Device (CSD) during an initial safety/feasibility study. In 11 patients, the only surgical measure was CSD placement. Most patients suffered from idiopathic cardiomyopathy; 4 were in NYHA class II, one was in class II/III, and 6 were in class III. All were stable on intensive medical treatment. The CSD, a textile polyester device, was fitted snugly around the heart during surgery. All patients survived surgery and recovered smoothly. Three months after surgery, 56% of patients were in NYHA class I, 33% were in class II, and 11% were in class II/III. Echocardiography showed an improvement in left ventricular ejection fraction from an average of 22% to 28% and 33% at 3 and 6 months, respectively. Simultaneously, the left ventricular end-diastolic dimension decreased from 74 mm to 68 mm and 65 mm, respectively. Mitral valve regurgitation (on a scale of 0 to 4+) decreased from 1.3 to 0.7 by 3 months. Quality-of-life indices correlated with the apparent reversal of ventricular remodeling. Preoperative cardiac medications remained virtually unchanged after implant.

CONCLUSIONS

In the short- and intermediate-term, CSD implantation seems to ameliorate symptoms and improve cardiac and functional performance in heart failure patients. Worldwide randomized trials are currently underway.

Use of plasma creatine kinase pharmacokinetics to estimate the amount of excercise-induced muscle damage in Beagles

OBJECTIVE

To assess the effects of moderate exercise on plasma creatine kinase (CK) pharmacokinetics and to estimate exercise-induced muscle damage in dogs.

ANIMALS

6 untrained adult Beagles.

PROCEDURE

The study was divided into 3 phases. In phase 1, dogs ran for 1 hour at a speed of 9 km/h, and samples were used to determine the area under the plasma CK activity versus time curve (AUC) induced by exercise. In phases 2 and 3, pharmacokinetics of CK were calculated in dogs during exercise and at rest, respectively. Values for AUC and plasma clearance (CI) were used to estimate muscle damage.

RESULTS

At rest, values for Cl, steady-state volume of distribution (Vdss), and mean retention time (MRT) were 0.32+/-0.02 ml/kg of body weight/min, 57+/-173 ml/kg, and 3.0+/-0.57 h, respectively. During exercise, Cl decreased significantly (0.26+/-0.03 ml/kg/min), MRT increased significantly, (4.4+/-0.97 h), and Vdss remained unchanged. Peak of plasma CK activity (151+/-58.8 U/L) was observed 3 hours after completion of exercise. Estimated equivalent amount of muscle corresponding to the quantity of CK released was 41+/-29.3 mg/kg.

CONCLUSION AND CLINICAL RELEVANCE

These results revealed that exercise had a minor effect on CK disposition and that the equivalent amount of muscle damaged by moderate exercise was negligible. This study illustrates the relevance for use of the minimally invasive and quantitative pharmacokinetic approach when estimating muscle damage.

Comparison of four methods for determination of total protein concentrations in pleural and peritoneal fluid from dogs

OBJECTIVE

To compare 4 techniques for determination of total protein concentrations in peritoneal and pleural effusions from dogs.

SAMPLE POPULATION

23 peritoneal and 12 pleural fluid samples from 35 dogs with various abnormalities.

PROCEDURE

Samples were collected into tubes containing EDTA, centrifuged, and stored at -20 C until total protein concentrations were assessed. Protein concentration in each sample was determined by use of urine test strips, refractometry, and Bradford and biuret techniques. Accuracy of each method was determined, using dilutions of human control sera.

RESULTS

There was good correlation among results of all quantitative procedures. Results of the biuret technique were more accurate than results of the Bradford assay. Refractometry underestimated protein concentration in samples with < 20 g of protein/L. Results of urine test strips correctly classified effusion samples into 2 groups on the basis of total protein concentrations less than or greater than 20 g/L.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of any of these 4 techniques can be used to rapidly and efficiently differentiate peritoneal and pleural fluid from dogs into transudates and exudates on the basis of total protein concentration less than or greater than 20 g/L, respectively.

Safety and feasibility of a cardiac support device

The Cardiac Support Device (CSD), a preformed-knitted polyester device surgically placed over the cardiac ventricles, prevents left ventricular (LV) remodeling and improves LV ejection fraction (EF) in dogs with heart failure (HF). This study was designed to examine the safety of the CSD in patients with advanced HF. As of December 31, 1999, the CSD was implanted into 22 patients with myocardial disease. Ten patients had concomitant mitral valve repair, two patients had valve replacement (one patient aortic and one patient mitral), one patient had LV assist device (LVAD) placement, and eight patients received only the CSD. The CSD was placed while on bypass with the heart beating, attached to the epicardium groove, and tailored anteriorly to snugly fit the ventricles. There were no intraoperative deaths or complications. Two patients died early from non-CSD-related causes 4 and 23 days postoperatively; one late death occurred. Of the remaining 19 patients, none had any CSD-related adverse events during an average 3.5 +/- 0.4 month follow-up. All patients had completed 3-month follow-up. No patients had evidence of constrictive and/or restrictive physiology. Mitral valve regurgitation (MVR) improved in all patients. [table: see text] Initial findings indicate that the CSD is safe and improves heart failure symptoms and LV function. Additional studies and longer follow-up are needed to confirm these results.

Overestimation of the predictive value of positives by the usual calculations of the specificity of diagnostic tests

The specificity of a diagnostic test for a given disease, i.e. the percentage of true negatives, can be calculated from either the results from a group of healthy animals or possibly from a group which also contains diseased animals which are free of the particular disease for which the test has been performed. The specificity may be much lower in the latter case and the predictive value of positives thus greatly reduced. In the example of creatine kinase being used for the diagnosis of muscle diseases in dogs, the specificity at the thresholds of 105 and 150 U/L (upper limits of the 95% and 99.7% interquantiles) decreased from 0.98 and 1.0 to 0.66 and 0.78, respectively.

In vivo quantification of muscle damage in dogs after general anaesthesia with halothane and propofol

Muscle damage in dogs anaesthetised with halothane and propofol was quantified by measurement of the area under the curve of plasma creatine kinase (CK) versus time. Plasma CK remained unchanged during anaesthesia for two and a half and five hours. Following halothane anaesthesia of dogs (resting on one side directly on the surgical table or on cushions, and with or without rotation of the body every 30 minutes), plasma CK was elevated in some animals to 10,000 U/litre by the 12th hour (baseline value < or = 100 u/litre), whereas it remained almost unchanged in other animals. Plasma CK then returned to reference values on day 2 or 3. The mean equivalent of muscle damaged ranged from 0.6 to 0.9 g/kg bodyweight. No muscle damage could be demonstrated in animals anaesthetised with propofol. It is therefore concluded that plasma CK should not be used as a diagnostic aid following halothane anaesthesia because of false positives due to the halothane anaesthesia itself and that propofol is best suited for the investigation of muscle damage due to surgical procedures.

Plasma erythropoietin concentrations in dogs and cats: reference values and changes with anaemia and/or chronic renal failure

Reference ranges of plasma erythropoietin concentration measured by immunoassay in 67 healthy cats and 40 healthy dogs were 1.9 to 22.9 mU ml-1 and 1.3 to 13.4 mU ml-1 respectively. Very significant increases of plasma erythropoietin concentration were observed in 22 cats and 32 dogs with anaemia without chronic renal failure (CRF), but 35 cats and 37 dogs with CRF had normal or moderately reduced erythropoietin concentrations. In cats there was almost no overlap of erythropoietin between the groups but in dogs there was a significant overlap. The measurement of plasma erythropoietin is therefore probably more useful in the diagnosis of anaemia in cats than in dogs, either with or without CRF.

The effect of experimental renal failure on tolfenamic acid disposition in the dog

The pharmacokinetic disposition of tolfenamic acid, an NSAID, after a single administration of tolfenamic acid (4 mg kg(-1)) by the intravenous (IV) route was compared in eight dogs before and after a surgically induced renal failure. Renal impairment was confirmed by a significant increase (p <0.001) of water intake, urine volume, and urea and creatinine plasma concentration. PAH and inulin clearances decreased after surgery from 15.2 +/- 4.2 to 9.5 +/- 0.8 mL kg(-1) min(-1) (p < 0.05) and from 4.37 +/- 1.15 to 2.43 +/- 0.88 mL kg(-1) min(-1) (p=0.067),respectively. After surgery, clearance of TA was significantly (p <0.001) increased, from 2.22 +/- 1.68 to 3.59 +/- 1.81 mL kg (-1) min(-1). There was no modification of the steady-state volume of distribution (p > 0.05) and the mean residence time was significantly decreased from 606 +/- 199 to 373 +/- 302 min (p < 0.05). No variation of binding to plasma proteins (> or = 99%) was observed. These results suggest that renal insufficiency could increase hepatic metabolism and/or alter the enterohepatic cycle of TA.

A non-invasive and quantitative method for the study of tissue injury caused by intramuscular injection of drugs in horses

The present study was undertaken to measure the weight of muscle destroyed by an intramuscular injection of phenylbutazone (PBZ) in horses. In six horses, CK disposition parameters were evaluated after intravenous (i.v.) and intramuscular (i.m.) administration of a CK horse preparation. The same horses received PBZ, a potentially irritating agent, by i.v. and i.m. (neck and hindquarter) routes. Data were analysed using compartmental approaches and instantaneous CK flux was calculated using a discrete deconvolution method. For a 150 U/kg CK dose, the steady-state volume of distribution was 0.050 +/- 0.0115 L/kg and the plasma half-life was 112 +/- 18 min. After CK i.m. administration, the half-life of the terminal phase was 11.8 +/- 5.3 h indicating a flip-flop process and the mean bioavailability of CK was close to 100%. After PBZ i.m. administration, the CK activity was significantly increased with peak values of 508 +/- 109 U/L after the neck administration and 873 +/- 365 U/L after the gluteal administration. By measuring the total amount of CK released from injured muscle, it was calculated that an equivalent of 0.044 +/- 0.029 g/kg of muscle was destroyed after PBZ administration in the neck. The corresponding figure was 0.118 +/- 0.048 g/kg after intragluteal PBZ administration. By deconvoluting plasma CK activity, it was shown that the CK entry rate was maximum for the first 30-60 min following PBZ administration, which then decreased slowly to return to the control value after a delay of 24-48 h after PBZ administration. It was concluded that the CK release pattern following a controlled muscular damage was a non-invasive approach useful for quantifying the amount of damaged muscle, and that the calculation of CK input rate by deconvolution was of potential interest in describing events at the muscle cell level.

In vivo non-invasive quantification of muscle damage following a single intramuscular injection of phenylbutazone in sheep

Intramuscular drug administration can lead to more or less extensive muscle damage. The aim of the present study was to show the possibility of quantitating, in vivo and non-invasively, the equivalence of muscle destroyed by the administration of a test drug (phenylbutazone) known for its injurious properties. Creatine kinase (CK) kinetic parameters (clearance, volume of distribution) were measured in 6 sheep after an iv administration of muscle CK homogenate. In the same 6 sheep, CK release after iv and im 8 mg phenylbutazone/kg was measured. The calculated total CK released, based on the CK plasma clearance (0.28 mL/kg/min) and area under the curve of CK activity after im phenylbutazone administration was 191 +/- 140 U/kg. By relating this quantity to that of CK gluteal muscle (5114 +/- 891 U/g), it was calculated that im phenylbutazone administration was able to destroy an equivalence of 2.4 +/- 2.1 g of muscle. For the 2 main sites of im administration (neck and gluteal muscle), general equations are proposed to calculate the equivalence of muscle destroyed in sheep when only plasma CK activity following a test drug administration is available.

In vivo quantification of muscle damage in dogs after intramuscular administration of drugs

Intramuscular injections of a vitamin B preparation, imidocarb, imidocarb+lidocaine, and a preparation of salts of fatty acids produced significant increases in plasma creatine kinase activity in groups of five to six dogs. Activities peaked between 3 and 8 h, and were as high as 23 times base values with the fatty acid salts preparation. Quantification of the equivalent muscle damage gave means of 0.04, 0.25, 0.23 and 0.30 g kg-1 body weight, respectively, for each of the above preparations.

Disposition of creatine kinase activity in dog plasma following intravenous and intramuscular injection of skeletal muscle homogenates

The fate of skeletal muscle-derived creatine kinase (CK) was investigated in six dogs. After i.m. and i.v. injections of 3000 g and 105,000 g supernatants of dog muscle homogenates, plasma CK activity was measured up to 48 h. There was no significant difference in pharmacokinetic parameters dependent on the type of supernatant injected. After i.v. injection, the volume of distribution of CK was equal to the plasma volume, CK clearance was relatively low (about 0.5 mL/kg/min) and its terminal half-life of elimination was about 2.5 h. After i.m. injection, the CK terminal half-life was about 6.5 h, demonstrating a flip-flop mechanism, i.e. a limiting absorption process from the site of injection. Bioavailability after i.m. injection was about 65%, and the rate of absorption from muscle injection site was relatively slow: peak activity occurred at the second hour post administration, and most CK activity had been absorbed by 24 h. These pharmacokinetic parameters can be used as a basis for a minimally invasive means of quantitating muscle damage either after intramuscular drug administration or in canine sports medicine.

Serum chemistry values for Arabian sand gazelles (Gazella subgutturosa marica)

Values for urea, creatinine, glucose, total bilirubin, sodium, potassium, chloride, calcium, phosphates, magnesium, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate deshydrogenase, and creatine-kinase are reported for the first time for 32 sand gazelles (Gazella subgutturosa marica) in Saudi Arabia. Comparisons were made between two groups: one sampled before a trip and the other sampled after a 14 hr trip. Only aspartate aminotransferase was higher in the second group; magnesium and phosphates were lower in that group.

Pharmacokinetic variables and bioavailability from muscle of creatine kinase in cattle

Pharmacokinetic variables of skeletal muscle creatine kinase (CK) activity after IV administration of a muscle extract; CK bioavailability after IM administration of the muscle extract; and effect of IM administration of saline solution, to appreciate the possible release of CK consecutive to muscle puncture, were determined in 6 cows. A general equation for the quantitative estimation of skeletal muscle damage also was derived. Administration of saline solution IM had no effect on plasma CK activity (ANOVA, P > 0.05) in any of the cows. After IV administration of the muscle extract (150 U/kg of body weight), mean volume of the central compartment, plasma half-life, and plasma clearance of CK were 0.027 +/- 0.007 L/kg, 520 +/- 109 minutes, and 6.43 +/- 2.29 ml/kg/h, respectively. After IM administration (150 U/kg), mean bioavailability of CK was 51 +/- 17% and maximal plasma CK activity (500 +/- 97 U/L) was observed at 454 +/- 131 minutes. The rate of CK activity entry into plasma was determined by use of deconvolution analysis. Two peaks were observed; the first appeared before the 30th minute after IM administration, and the second appeared at 3.3 +/- 1.1 hours. Amplitudes were 6.31 +/- 4.45 and 6.57 +/- 3.08 U/kg/h, for the first and the second peaks, respectively. The quantity of CK liberated from control muscle was 0.69 +/- 0.12 U/kg/h, corresponding to a normal daily catabolism of 5.8 +/- 1.0 mg of muscle/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetic evaluation of muscle damage during exercise by calculation of amount of creatine kinase released

To quantify the extent of muscle alteration during prolonged exercise, the release rate of creatine kinase (CK) from striated muscle was measured in six horses during a rest period (6 h) and during three exercise tests (15, 30, and 60 km) at a constant speed of 200 m/min. CK clearance was measured after intravenous bolus administration (150 U/kg) of a CK solution obtained from horse muscle. The CK steady-state volume of distribution was 0.059 +/- 0.0215 l/kg, the terminal half-life was 123 +/- 28 min, and the plasma clearance was 0.36 +/- 0.10 ml.kg-1 x min-1. After an intramuscular CK administration, the CK systemic availability was 74.1 +/- 21.2% and the half time of absorption was 9.4 +/- 5.7 h, indicating a slow process for CK transit through the lymphatic system. The CK release rate was only significantly increased during the 60-km exercise test. The increase of CK plasma activity was observed after a delay of approximately 5 h and peaked after the end of the race; the estimated CK release rate was 9.92 +/- 2.62 U.kg-1 x h-1 over a mean duration period of 65.8 +/- 15.8 h. With the CK activity of horse striated muscle taken into account, a 60-km race released a quantity of CK corresponding to an equivalent of 18.8 +/- 4.3 g striated muscle. It is concluded that the equivalent amount of damaged muscle may be considered as negligible for a 60-km test and that only very high plasma CK activity levels (at least higher than 10,000 U/l) may provide some evidence of a myolysis.

Genetic blood markers in Arabian, Barb and Arab-Barb horses in Morocco

Gene frequencies at 16 blood group and protein polymorphism loci (A, C, D, K, P, Q, U, Al, Gc, Es, A1B, Tf, PGD, PGM, GPI and Pi) are given for three horse breeds in Morocco (Arabian, Arab-Barb and Barb). These data are used to calculate average heterozygosity (h), Nei's standard genetic distance (DN) and probability of exclusion (PE). Variability expressed as the average heterozygosity was lower in the Arabian (0.330 +/- 0.066), while it was higher and almost the same in the Arab-Barb (0.413 +/- 0.071) and the Barb (0.414 +/- 0.070). The shortest genetic distance was found between Barb and Arab-Barb. The 16 loci used are at least 95% effective for recognizing incorrect paternity in these breeds. The Barb and Arab-Barb genetic profiles obtained showed the rare variants interesting perhaps in the context of European and American breeds: notably Dcfgkm, Ddekl, Es-N, Tf-A and Pi-W.

Creatine kinase in dog plasma: preanalytical factors of variation, reference values and diagnostic significance

In the dog, plasma creatine kinase (CK) activity was stable up to one week at +4 degrees C and one month at -20 degrees C. Activity was higher in serum than in plasma due to interference by CK from the platelets. The reference values were determined in 232 dogs using the IFCC recommended method. There was a significant decrease in activity with age but no effect of sex. In adults, plasma CK exhibited a log-normal distribution ranging from 20 to 104 U per litre. In 510 dogs with various diseases, the overall sensitivity and specificity of CK determination were 40 per cent and 98 per cent, respectively. The numerous false negatives could result from the relatively short half-life of the enzyme, while the false positives could be due to secondary muscle damage.