Reference limits for blood gas analysis performed from coccygeal vessels of multiparous Holstein dairy cows: Effects of stage of lactation and season of sampling.

Blood gas analysis is a great support to the diagnostic process of critically ill patients. Its correct application to the medicine of dairy cows depends on the availability of specific reference intervals that are still difficult to find in the literature. They may vary according to the type of blood sampled, animals' age and production stage, and climatic conditions. This study aimed at calculating the reference limits for some blood gas parameters in the blood collected from the coccygeal vessels of multiparous Holstein dairy cows. This site of sampling implies the risk of withdrawing blood of unknown origin (venous, arterial, or mixed), but has a high practical interest for the easy and quick performance and the minimal animal restraint required. Data from 379 cows were used, and reference limits were produced for pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3), total carbon dioxide concentration (tCO2), oxygen saturation (sO2), hemoglobin (Hb), hematocrit (Hct), base excess (BE), glucose, Na, K, and ionized calcium (iCa). The effects of stage of lactation (5 to 60 vs. > 60 DIM) and season of sampling (cold vs. hot) were investigated, and specific reference limits were produced for each variable and each level of the factors whenever a significant effect was detected. The pH, sO2, K, and iCa were not influenced by season or stage of lactation. All the other blood gas parameters were significantly affected by season of sampling, and Hb, Hct, glucose, and Na were also affected by stage of lactation. Reference limits provided in this study are specific to the site of sampling (coccygeal vessels) and the animal category considered. Further studies are needed to produce reference intervals for other blood gas parameters, cow categories, and blood types.

Aortopexy for the management of paediatric tracheomalacia - the Alder Hey experience.

BACKGROUND: Whilst aortopexy is an accepted and established procedure, there remains considerable heterogeneity within the literature, with inconsistencies in both the approach taken and the technique employed. Furthermore, limited data exist on both patient selection and long-term outcomes. This study aimed to report the experience of managing severe tracheomalacia by way of aortopexy in a large UK paediatric centre. METHOD: A retrospective case note review was conducted. Mean follow up was five years. RESULTS: Twenty-five patients underwent aortopexy for severe tracheomalacia caused by external vascular compression. Acute life-threatening events precipitated investigation in 72 per cent of cases. Twenty-one patients initially presented to ENT services for investigation, which comprised upper airway endoscopy and imaging with computed tomography angiography. Post-operatively, the majority of patients demonstrated complete resolution of symptoms and were discharged from all associated services. Only four patients required a tracheostomy. CONCLUSION: Aortopexy offers an effective method of treating severe tracheomalacia due to vascular compression.

Technical note: Rapid mineral determination in forages by X-ray fluorescence.

A large portion of the cow's ration is composed of forages that can vary greatly in mineral concentrations, which may affect animal performance and health. Current methods for mineral analysis require sample destruction either through wet or dry ashing and complex analytical techniques for individual minerals. Energy dispersive X-ray fluorescence (EDXRF) is a nondestructive, multi-mineral, spectroscopy technique, which makes mineral quantification simple, direct, and affordable. The study objective was to evaluate the prediction performance of EDXRF of Na, Mg, P, S, Cl, Ca, K, Mn, Fe, Cu, and Zn concentrations in forages. Twelve certified plant samples with a wide range in mineral concentrations were used to develop calibrations, and 35 forages (18 alfalfa hays, 10 grass hays, 7 corn silages) with measured mineral concentrations, which were collected over several years from 3 proficiency programs, were used as an independent validation set. All the samples were previously dried and finely ground and were prepared by compressing them into a round dense pellet, 40 mm in diameter, using a 40-ton pneumatic laboratory press. Samples were scanned using an EDXRF instrument enhanced for lighter minerals like Na and Mg. Samples were scanned at 20 keV and at 40 KeV associated with an Al filter, for a total analysis time of approximately 6 min. Calibrations were developed with Bruker SpectraEDX (Bruker, Hamburg, Germany) software and optimized to minimize the standard error of calibration. All of the minerals had acceptable calibration performance with coefficient of determination ranging from 0.93 (P) and 0.99 (Cl, Ca, and Mn) and coefficients of variation within 5 to 14%, which are similar to the coefficients of variation of the reference analysis. The coefficients of variation for Na was an exception, with a coefficients of variation of 29%. The validation set obtained similar statistical results as that observed in calibration. The root mean square error of prediction corrected for bias was similar to the standard error of calibration, indicating that it is possible to build a robust calibrations that performed well across different type of forages by using 12 reference samples with a sufficient range in mineral concentrations that were determined accurately. A bias correction was necessary to improve prediction accuracy only for K (-0.23% dry matter) and Ca (-0.16% dry matter). Energy dispersive X-ray fluorescence demonstrated the ability to be an accurate, direct, and simple technique for forage mineral analysis.

Extensive feeding on sockeye salmon Oncorhynchus nerka smolts by bull trout Salvelinus confluentus during initial outmigration into a small, unregulated and inland British Columbia river.

Stomach contents were collected and analysed from 22 bull trout Salvelinus confluentus at the edge of the Chilko Lake and Chilko River in British Columbia, Canada, during spring outmigration of sockeye salmon Oncorhynchus nerka smolts. Twenty of the 22 (>90%) stomachs contained prey items, virtually all identifiable prey items were outmigrant O. nerka smolts and stomach contents represented a large portion (0·0-12·6%) of estimated S. confluentus mass. The results demonstrate nearly exclusive and intense feeding by S. confluentus on outmigrant smolts, and support recent telemetry observations of high disappearance rates of O. nerka smolts leaving large natural lake systems prior to entering high-order unregulated river systems.

Does among-population variation in burst swimming performance of sockeye salmon Oncorhynchus nerka fry reflect early life migrations?

Using a fixed-speed test, burst swimming performance was found to vary among nine populations of emergent sockeye salmon Oncorhynchus nerka fry reared in a common-garden environment. No consistent relationship was, however, detected between difficulty of fry migration (upstream v. downstream) to rearing areas and total burst swimming duration or bursting rate.

Testing the synergistic effects of GnRH and testosterone on the reproductive physiology of pre-adult pink salmon Oncorhynchus gorbuscha.

To test the hypothesis that the hypothalmic gonadotropin-releasing hormone (GnRH) and testosterone (T) co-treatment stimulates both the hypothalmo-pituitary-gonadal (HPG) and hypothalmo-pituitary-interrenal axes, the reproductive and osmoregulatory responses of pre-adult pink salmon Oncorhynchus gorbuscha were compared after GnRH and T administration either alone or in combination. Relative to controls, neither GnRH nor T treatment resulted in significantly greater ovarian or testicular growth, but co-treatment significantly increased ovarian growth after 5 months. Interestingly, the stimulation was undetectable after 3 months. However, once daily photoperiod began shortening after the summer solstice, c. 2 months before the natural spawning date, GnRH+T-treated females were stimulated to produce larger ovaries. Final fish body length and the size of individual eggs did not differ among treatment groups. GnRH+T eggs, however, showed signs of advanced vitellogenesis relative to GnRH-treated and control eggs, whereas T-treated eggs became atretic. Testis size increased significantly from initial values and most males were spermiating, but this growth and development were independent of hormone treatments. Final plasma ion, metabolite and cortisol concentrations did not differ among treatment groups. It is concluded that GnRH+T co-treatment was effective in stimulating female but not male maturation. GnRH and T treatment, however, presumably had little effect on the hypothalmo-pituitary-interrenal axis as observed by ionoregulatory status.

Effects of experimental manipulations of salinity and maturation status on the physiological condition and mortality of homing adult sockeye salmon held in a laboratory.

Relatively little is known about the physiological response and mortality consequences of the return of anadromous fish to freshwater (FW). We explored the consequences of the return to FW by collecting maturing sockeye salmon from the marine waters off the mouth of the Fraser River and holding approximately 50 sockeye in each of five treatments: saltwater (SW; salinity = 28 ppt), iso-osmotic water (ISO; 13 ppt), FW (0 ppt), SW + gonadotropin-releasing hormone (SW + GnRH), and FW + GnRH. Exogenous GnRH treatments were intended to accelerate maturation. Results demonstrate that gill Na(+),K(+) ATPase activity, sex steroid concentrations, and cortisol levels were highly responsive to experimental manipulations and followed predicted trajectories (i.e., FW + GnRH sockeye were the most mature and FW adapted). There were few among-treatment differences in hematocrit and plasma concentrations of lactate, glucose, Na(+), Cl(-), and plasma osmolality among sockeye that survived to the end of treatments, indicating that sockeye rigorously maintain internal homeostatic conditions while alive. There were large among-treatment differences in mortality (SW+GnRH > SW> FW+GnRH > FW=ISO), and each treatment experienced a notable increase in mortality rate around the fifth day of treatment. Our results indicate that salinity represented a modestly larger challenge to the experimental sockeye than did the artificially accelerated sexual maturation. Our results also suggest that maturing sockeye either successfully acclimate to FW within 5 d of exposure or perish. These findings are consistent with the predictions of the theory of anadromy, in suggesting that the return of adults to FW can be physiologically challenging and can represent a period of significant natural mortality.

A case of a periaortic lymphoma presenting with the features of descending thoracic aorta dissection.

We report the case of a 68-year-old male in whom an intrathoracic non-Hodgkin's lymphoma was diagnosed late after he presented with the clinical and radiological features of a descending aortic dissection due to penetrating ulcer. An endovascular stent was implanted in the descending aorta. At follow up, a CT scan showed the presence of a mediastinal mass thought to be a periaortic haematoma as a consequence of the endovascular stent implantation. A further CT scan showed an increase in size of the mediastinal mass encasing the whole descending aorta. A biopsy of the mass was performed which was shown to be non-Hodgkin's lymphoma. This is the first report of a penetrating ulcer of the descending aorta due to lymphoma, which probably caused the dissection.

Routine and active metabolic rates of migrating adult wild sockeye salmon (Oncorhynchus nerka Walbaum) in seawater and freshwater.

We present the first data on the differences in routine and active metabolic rates for sexually maturing migratory adult sockeye salmon (Oncorhynchus nerka) that were intercepted in the ocean and then held in either seawater or freshwater. Routine and active oxygen uptake rates (MO2) were significantly higher (27%-72%) in seawater than in freshwater at all swimming speeds except those approaching critical swimming speed. During a 45-min recovery period, the declining postexercise oxygen uptake remained 58%-73% higher in seawater than in freshwater. When fish performed a second swim test, active metabolic rates again remained 28%-81% higher for fish in seawater except at the critical swimming speed. Despite their differences in metabolic rates, fish in both seawater and freshwater could repeat the swim test and reach a similar maximum oxygen uptake and critical swimming speed as in the first swim test, even without restoring routine metabolic rate between swim tests. Thus, elevated MO2 related to either being in seawater as opposed to freshwater or not being fully recovered from previous exhaustive exercise did not present itself as a metabolic loading that limited either critical swimming performance or maximum MO2. The basis for the difference in metabolic rates of migratory sockeye salmon held in seawater and freshwater is uncertain, but it could include differences in states of nutrition, reproduction, and restlessness, as well as ionic differences. Regardless, this study elucidates some of the metabolic costs involved during the migration of adult salmon from seawater to freshwater, which may have applications for fisheries conservation and management models of energy use.

The effect of temperature on swimming performance and oxygen consumption in adult sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon stocks.

Our knowledge of the swimming capabilities and metabolic rates of adult salmon, and particularly the influence of temperature on them, is extremely limited, and yet this information is critical to understanding the remarkable upstream migrations that these fish can make. To remedy this situation, we examined the effects of temperature on swimming performance and metabolic rates of 107 adult fish taken from three stocks of sockeye salmon Oncorhynchus nerka and one stock of coho salmon O. kisutch at various field and laboratory locations, using large, portable, swim tunnels. The salmon stocks were selected because of differences in their ambient water temperature (ranging from 5 degrees C to 20 degrees C) and the total distance of their in-river migrations (ranging from approximately 100 km for coastal stocks to approximately 1100 km for interior stocks). As anticipated, differences in routine metabolic rate observed among salmon stocks were largely explained by an exponential dependence on ambient water temperature. However, the relationship between water temperature and maximum oxygen consumption (MO2max), i.e. the MO2 measured at the critical swimming speed (Ucrit), revealed temperature optima for MO2max that were stock-specific. These temperature optima were very similar to the average ambient water temperatures for the natal stream of a given stock. Furthermore, at a comparable water temperature, the salmon stocks that experienced a long and energetically costly in-river migration were characterized by a higher MO2max, a higher scope for activity, a higher Ucrit and, in some cases, a higher cost of transport, relative to the coastal salmon stocks that experience a short in-river migration. We conclude that high-caliber respirometry can be performed in a field setting and that stock-specific differences in swimming performance of adult salmon may be important for understanding upstream migration energetics and abilities.

Excess post-exercise oxygen consumption in adult sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon following critical speed swimming.

The present study measured the excess post-exercise oxygen cost (EPOC) following tests at critical swimming speed (Ucrit) in three stocks of adult, wild, Pacific salmon (Oncorhynchus sp.) and used EPOC to estimate the time required to return to their routine level of oxygen consumption (recovery time) and the total oxygen cost of swimming to Ucrit. Following exhaustion at Ucrit, recovery time was 42-78 min, depending upon the fish stock. The recovery times are several-fold shorter than previously reported for juvenile, hatchery-raised salmonids. EPOC varied fivefold among the fish stocks, being greatest for Gates Creek sockeye salmon (O. nerka), which was the salmon stock that had the longest in-river migration, experienced the warmest temperature and achieved the highest maximum oxygen consumption compared with the other salmon stocks that were studied. EPOC was related to Ucrit, which in turn was directly influenced by ambient test temperature. The non-aerobic cost of swimming to Ucrit was estimated to add an additional 21.4-50.5% to the oxygen consumption measured at Ucrit. While these non-aerobic contributions to swimming did not affect the minimum cost of transport, they were up to three times higher than the value used previously for an energetic model of salmon migration in the Fraser River, BC, Canada. As such, the underestimate of non-aerobic swimming costs may require a reevaluation of the importance of how in-river barriers like rapids and bypass facilities at dams, and year-to-year changes in river flows and temperatures, affect energy use and hence migration success.

Myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using cold or warm blood cardioplegia.

OBJECTIVES: Myocardial protection techniques during cardiac surgery have been largely investigated in the clinical setting of coronary revascularisation. Few studies have been carried out on patients with left ventricular hypertrophy where the choice of delivery, and temperature of cardioplegia remain controversial. This study investigates metabolic changes and myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using antegrade cold or warm blood cardioplegia. METHODS: Thirty-five patients were prospectively randomised to intermittent antegrade cold or warm blood cardioplegia. Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury. RESULTS: Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. During reperfusion, alanine/glutamate ratio was higher than preischaemic levels in both groups, but the extent of the increase was considerably greater in the warm blood group. Troponin I release was markedly (P<0.05, Mean+/-SD) lower at 1, 24 and 48h postoperatively in the cold compared to the warm blood group (0.51+/-0.37, 0.37+/-0.22 and 0.27+/-0.19 vs. 0.75+/-0.42, 0.73+/-0.51 and 0.54+/-0.38ng/ml for cold vs. warm group, respectively). CONCLUSIONS: Cold blood cardioplegia is associated with less ischaemic stress and myocardial injury compared to warm blood cardioplegia in patients with aortic stenosis undergoing valve replacement surgery. Both cardioplegic techniques, however, confer sub-optimal myocardial protection.

Influence of fundamental frequency on stop-consonant voicing perception: a case of learned covariation or auditory enhancement?

For stimuli modeling stop consonants varying in the acoustic correlates of voice onset time (VOT), human listeners are more likely to perceive stimuli with lower f0's as voiced consonants--a pattern of perception that follows regularities in English speech production. The present study examines the basis of this observation. One hypothesis is that lower f0's enhance perception of voiced stops by virtue of perceptual interactions that arise from the operating characteristics of the auditory system. A second hypothesis is that this perceptual pattern develops as a result of experience with f0-voicing covariation. In a test of these hypotheses, Japanese quail learned to respond to stimuli drawn from a series varying in VOT through training with one of three patterns of f0-voicing covariation. Voicing and f0 varied in the natural pattern (shorter VOT, lower f0), in an inverse pattern (shorter VOT, higher f0), or in a random pattern (no f0-voicing covariation). Birds trained with stimuli that had no f0-voicing covariation exhibited no effect of f0 on response to novel stimuli varying in VOT. For the other groups, birds' responses followed the experienced pattern of covariation. These results suggest f0 does not exert an obligatory influence on categorization of consonants as [VOICE] and emphasize the learnability of covariation among acoustic characteristics of speech.

Language acquisition as complex category formation.

Purported units of speech, e.g. phonemes or features, are essentially categories. The assignment of phonemic (or phonetic) identity is a process of categorization: potentially discriminable speech sounds are treated in an equivalent manner. Unfortunately the extensive literature on human categorization has typically focused on simple visual categories that are defined by the presence or absence of discrete features. Speech categories are much more complex. They are often defined by continuous values across a variety of imperfectly valid features. In this paper, several kinds of categories are distinguished and studies using human subjects, animal subjects and computational models are presented that endeavor to describe the structure and development of the sort of complex categories underlying speech perception.

Neighboring spectral content influences vowel identification.

Four experiments explored the relative contributions of spectral content and phonetic labeling in effects of context on vowel perception. Two 10-step series of CVC syllables ([bVb] and [dVd]) varying acoustically in F2 midpoint frequency and varying perceptually in vowel height from [delta] to [epsilon] were synthesized. In a forced-choice identification task, listeners more often labeled vowels as [delta] in [dVd] context than in [bVb] context. To examine whether spectral content predicts this effect, nonspeech-speech hybrid series were created by appending 70-ms sine-wave glides following the trajectory of CVC F2's to 60-ms members of a steady-state vowel series varying in F2 frequency. In addition, a second hybrid series was created by appending constant-frequency sine-wave tones equivalent in frequency to CVC F2 onset/offset frequencies. Vowels flanked by frequency-modulated glides or steady-state tones modeling [dVd] were more often labeled as [delta] than were the same vowels surrounded by nonspeech modeling [bVb]. These results suggest that spectral content is important in understanding vowel context effects. A final experiment tested whether spectral content can modulate vowel perception when phonetic labeling remains intact. Voiceless consonants, with lower-amplitude more-diffuse spectra, were found to exert less of an influence on vowel perception than do their voiced counterparts. The data are discussed in terms of a general perceptual account of context effects in speech perception.

Inflammatory response after coronary revascularization with or without cardiopulmonary bypass.

BACKGROUND: We sought to investigate the effect of multiple coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass (CPB) on the perioperative inflammatory response. METHODS: Sixty patients undergoing CABG were randomly assigned to one of two groups: (A) on pump with conventional CPB and cardioplegic arrest, and (B) off pump on the beating heart. Serum samples were collected for estimation of neutrophil elastase, interleukin 8 (IL-8), C3a, and C5a preoperatively and at 1, 4, 12, and 24 hours postoperatively. Furthermore, white blood cell (WBC), neutrophil, and monocyte counts were carried out preoperatively and at 1, 12, 36 and 60 hours postoperatively. Overall incidence of infection and perioperative clinical outcome were also recorded. RESULTS: The groups were similar in terms of age, weight, gender ratio, extent of coronary disease, left ventricular function, and number of grafts per patient. Neutrophil elastase concentration peaked early after CPB in the on-pump group, with a decline with time. Repeated-measures analysis of variance between groups and comparisons at each time point (modified Bonferroni) showed elastase concentrations were significantly higher in the on-pump than the off-pump group (both p < 0.0001). IL-8 increased significantly after surgery in the on-pump group, with no decline during the observation period (p = 0.01 vs off pump). C3a and C5a rose early after surgery in both groups when compared with baseline values. Postoperative WBC, neutrophil, and monocyte counts were significantly higher in the on-pump than the off-pump group (p < 0.01). Finally, the incidence of postoperative overall infections was significantly higher in the on-pump group (p < 0.0001 vs off pump). CONCLUSIONS: CABG on the beating heart is associated with a significant reduction in inflammatory response and postoperative infection when compared with conventional revascularization with CPB and cardioplegic arrest.

Evaluation of myocardial metabolism and function during beating heart coronary surgery.

Coronary artery bypass surgery on the beating heart either via a left anterior small thoracotomy (LAST) or a median sternotomy is becoming increasing popular world-wide. Concern still remains about the potential for a temporary regional myocardial ischaemia associated with the stabilisation and occlusion of the coronary during construction of the anastomosis. This review summarises the results of a series of studies intended to evaluate the effect of beating heart coronary revascularization on myocardial function, myocardial tissue injury and clinical outcome.

Nonembolic predictors of stroke risk in coronary artery bypass patients.

The aim of this study was to identify and stratify the most important nonembolic risk factors for stroke after coronary bypass grafting. From June 1994 to June 1997 a series of 1532 patients (pts) underwent isolated myocardial revascularization on cardiopulmonary bypass (CPB). A retrospective chart review selected 1417 pts in whom the presence of aortic calcification or left ventricular mural thrombi was not detectable by echocardiogram, angiogram, and intraoperative records. Univariate and multivariate analyses were conducted to identify nonembolic variables independently correlated to postoperative stroke. A predictive model of stroke probability was then constructed by means of a mathematic method with the variables selected from logistic regression analyses. The global incidence of stroke was 1.8%. Univariate analysis revealed that, among 29 preoperative and operative variables, age, vasculopathy, emergency operation, previous cerebrovascular accident (CVA), CPB, and aortic cross-clamping times were factors strongly associated with postoperative stroke (p < 0.01). A first logistic regression analysis (LRA) selected as independent predicting variables (p < 0.05) age [odds ratio (OR) 1.07/year], vasculopathy (OR 4), previous CVA (OR 7.2), CPB time (OR 1/year), and emergency operation (OR 4.2). In a second stepwise LRA, age and CPB time were subdivided into cohorts as follows: age 65 but < 75 years, >/= 75 years; CPB time 120 but < 180 minutes, >/= 180 minutes. Both age >/= 75 years (p = 0.024; OR 3.3) and CPB time >/= 180 minutes (p = 0.002; OR 4.2), were found to be predictors of postoperative neurologic damage. Finally, a probability table of stroke risk was obtained with the logistic regression coefficients. A lower stroke probability (0.7%) was calculated in the absence of risk variables and a higher one in the presence of all of them (83.3%). Between these extremes, a total of 158 combinations of stroke probabilities were obtained. We concluded that previous CVA, vasculopathy, emergency operation, and age > 75 years are variously associated with a high risk of nonembolic stroke after myocardial revascularization. A duration of CPB longer than 3 hours strongly increases the probability of neurologic damage in the presence of the aforementioned variables.

[Coronary surgery without extracorporeal circulation: the short-term results in high-risk patients]. / Chirurgia coronarica senza circolazione extracorporea: risultati a breve termine nei pazienti ad alto rischio.

BACKGROUND: This study was conducted to assess the impact of coronary bypass surgery (CABG) without cardiopulmonary bypass (CPB) on high-risk patients. METHODS: From February 1997 to July 1998, 71 patients considered at high-risk underwent a CABG off-pump. Using the "Higgins score", eleven preoperative risk factors were identified and stratified in this group of patients. Among 1271 patients who underwent CABG with CPB in the same period, using a computer-based matched comparison, a second identical group of patients was selected according to the 11 risk variables and the number with coronary disease, so that complete preoperative matching included the year of operation, score index and coronary target. Moreover, among seven other preoperative variables that were not included in the matching comparison, the two groups differed only in mean age (64 +/- 10.9 vs 61.6 +/- 7.3 in groups off and on-pump, respectively, p < 0.05). Postoperative outcome and complications and blood requirement were compared. Myocardial cell injury and left ventricular performance were also assessed in the two groups. RESULTS: The global incidence of neurologic complications in the off-pump group was significantly lower (9.8 vs 0%, in on and off-pump groups, respectively; p = 0.02). Patients undergoing CABG off-pump required blood far less often (% of transfused patients: 26.7% for the patients with CPB and 11.2% for the patients without CPB; p = 0.032). Three patients from the on-pump group (4.2%) had a perioperative myocardial infarction (AMI), versus 0% of the off-pump cases (p = ns). Postoperative atrial fibrillation accounted for 14.1% in off-pump patients and 30.9% in on-pump patients (p = 0.027). One patient in both groups (1.4%) suffered from postoperative heart failure. Mean ventilation time and ICU stay did not differ significantly between the two groups. However, hospital discharge occurred earlier in the off-pump group (9.3 +/- 3 vs 12.6 +/- 8, p = 0.007). In-hospital death occurred in one case from the on-pump group (1.4%) versus 0% of patients operated off-pump. CPK-MB release in patients without perioperative AMI was significantly lower in off-pump patients 6 and 12 hours after the operation (36.6 +/- 17 IU/l vs 69.8 +/- 23 IU/l after 6 hours, p < 0.05; and 36.7 +/- 19 IU/l vs 67.3 +/- 26 IU/l after 12 hours, p < 0.05, in off and on-pump groups, respectively) and LVSWI turned out to be better in off-pump patients 6 hours postoperatively (34.2 +/- 2 g*m/m2 vs 27.2 +/- 3 g*m/m2, p < 0.01). CONCLUSIONS: CABG without CPB seems to be a promising technique for high-risk patients. It offers better neurologic and cardiac protection, shortens postoperative hospital stay and reduces the need for blood transfusion.

Economic outcome of off-pump coronary artery bypass surgery: a prospective randomized study.

BACKGROUND: Emphasis on cost containment in coronary artery bypass surgery is becoming increasingly important in modern hospital management. The revival of interest in off-pump (beating heart) coronary artery bypass surgery may influence the economic outcome. This study examines these effects. METHODS: Two hundred patients undergoing first-time coronary artery bypass surgery were prospectively randomized to either conventional cardiopulmonary bypass and cardioplegic arrest or off-pump surgery. Variable and fixed direct costs were obtained for each group during operative and postoperative care. The data were analyzed using parametric methods. RESULTS: There was no difference between the groups with respect to pre- and intraoperative patient variables. Off-pump surgery was significantly less costly than conventional on-pump surgery with respect to operating materials, bed occupancy, and transfusion requirements (total mean cost per patient: on pump, $3,731.6+/-1,169.7 vs off-pump, $2,615.13+/-953.6; p < 0.001). Morbidity was significantly higher in the on-pump group, which was reflected in an increased cost. CONCLUSIONS: Off-pump revascularization offers a safe, cost-effective alternative to conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest.