Intra-institutional prediction of outcome after cardiac surgery: comparison between a locally derived model and the EuroSCORE

Objective: To construct models for predicting mortality, morbidity and length of intensive care unit (ICU) stay after cardiac surgery and to compare the performance of these models with that of the EuroSCORE in two independent validation databases. Methods: Clinical data on 4592 cardiac surgery patients operated between 1992 and 1996 were retrospectively collected. In order to derive predictive models and to validate them, the patient population was randomly divided into a derivation database (n=3061) and a validation database (n=1531). Variables that were significant in univariate analyses were entered into a backward stepwise logistic regression model. The outcome was defined as mortality within 30 days after surgery, predefined morbidity, and the length of ICU stay lasting >2 days. In addition to the retrospective database, the models were validated also in a prospectively collected database of cardiac surgical patients operated in 1998–1999 (n=821). The EuroSCORE was tested in two validation databases, i.e. the retrospective and prospective one. Hosmer–Lemeshow goodness-of-fit was used to study the calibration of the predictive models. Area under the receiver operating characteristic (ROC) curve was used to study the discrimination ability of the models. Results: The overall mortality in the retrospective and the prospective data was 2 and 1%, and morbidity 22 and 18%, respectively. The created predictive models fitted well in the validation databases. Our models and the EuroSCORE were equally good in discriminating patients. Thus, in the prospective validation database, the mean areas under the ROC curve for our models and for the EuroSCORE were similar, i.e. 0.84 and 0.77 for mortality, 0.74 and 0.74 for morbidity, and 0.81 and 0.79 for the length of intensive care unit stay lasting for 2 days or more, respectively. Conclusions: Our models and the EuroSCORE were equally good in discriminating the patients in respect to outcome. However, our model provided also well calibrated estimation of the probability of prolonged ICU stay for each patient. As was originally suggested, the EuroSCORE may be an appropriate tool in categorizing cardiac surgical patients into various subgroups in interinstitutional comparisons. Our models may have additive value especially in resource allocation and quality assurance purposes for local use.     

Management of vesicoureteral reflux in patients with neurogenic bladder dysfunction

We studied 20 cases of neurogenic bladder with vesico-ureteral reflux retrospectively. Seven patients voided with Valsalva's maneuver and 12 patients were managed with clean intermittent catheterization, but one patient required permanent urinary diversion because of uncontrollable urinary tract infection. The patients were followed by intravenous pyelography, radioisotope renogram, voiding cystourethrography, determination of serum creatinine level and urodynamic study. Anti-reflux surgery was performed in 22 ureters and reflux resolved in 19 ureters. Among 12 ureters not treated by anti-reflux surgery, reflux disappeared in 5 ureters and improved in 2 ureters. Of 5 ureters, reflux resolved after clean intermittent catheterization in 2 ureters, and remained stable without recurrent infection or renal deterioration in the remaining 5 ureters. Regardless whether antireflux surgery was done or not, most of the patients who had high grade reflux and obstructive renal damage on radioisotope examinations had marked low compliance bladders. Our experience suggested the necessity of a suitable treatment to improve bladder compliance before considering anti-reflux surgery.     

Pre-focal plane high-temperature regions induced by scanning focused ultrasound beams

A steady-state, three dimensional, bioheat transfer equation-based simulation program has been developed and used with single and multiple transducer arrangements to investigate the effects of spherical transducer characteristics (frequency and f-number) and scanning patterns on treatment temperature distributions. Results for uniformly perfused tissues show that: (1) a single circular scan induces radially non-uniform temperature distributions at the focal depth and undesirable pre-focal high temperature regions; and (2) multiple circular scans spaced by the focal diameter of the ultrasound beam and using feedback control can induce uniform temperature distributions in the focal plane, but still cause undesirable pre-focal plane high temperatures. These two results apply both to a single transducer scanned with its axis normal to the skin and to multiple tilted transducers with overlapping foci. The extent and magnitude of this pre-focal high-temperature region increases as frequency increases (from 0.5 to 2.0 MHz) and as the f-number increases (from 1.0 to 2.0). Finally, (3) when four tilted transducers with overlapping foci are used with multiple circular scans spaced by the focal diameter, if the transducer closest to the central axis of the scans is turned off (every transducer is turned off periodically) the pre-focal high-temperature region can be eliminated. From the results of this parametric study and practical considerations, a reasonable compromise of transducer choice for general use is one with a low f-number (about 1.0) and a frequency of about 1.0 MHz. For multiple tilted transducers with overlapping foci the choice of frequency is also 1.0 MHz and the f-number should be as low as possible.     

Functional electrical stimulation in the management of incontinence: Studies of urodynamics

Intermittent functional electrical stimulation (FES) was employed for the control of incontinence. One FES session lasted for 30 minutes. It was repeated at intervals of 3 days to 1 week via an anal plug electrode. The success rate was 64% in 41 patients with pollakiuria, urgency and/or urge incontinence, and 43% in 7 patients with stress incontinence. Detrusor activity measured by cystometry did not correlate significantly with the effect on subjective symptoms and the urethral pressure did not increase. The remarkable clinical effect was observed in patients with overactive detrusor function. It seems that FES indirectly inhibits detrusor contraction by suppressing the intrasacral pathway for detrusor activity.     

Is there a linkage between metabolism and personality in small mammals? The root vole (Microtus oeconomus) example

Significant inter-individual variation in the rate of animal metabolism is a widespread phenomenon that has started to accumulate general interest. Here we follow recent calls to focus on linkage between the variation in energy metabolism and animal personality. By using wild caught root voles as a study species, we examined the relationship between the behavioral patterns (assessed in open field test) and resting metabolic rate (RMR), both of which are known to show large individual differences and intra-individual consistency in voles. Our results showed only a weak relationship between personality traits and metabolism, since the most parsimonious model (according to AICc) explaining RMR included only body mass and season as factors (explaining 84.8% of variation in RMR). However, the next two alternative models (within ΔAICc = 2) also included the personality trait reflecting proactive behaviors (PC1) in addition to body mass, sex and season (85.2 and 85.8% of RMR variance explained, respectively). In all, our study does not provide compelling support for recent ideas of close linkage between behavior and metabolism. Still, our study highlights that even in the case of wild caught individuals, when behavior and metabolism often carry effects of both intrinsic and extrinsic conditions, the potential metabolic effects of varying energetically costly behaviors cannot be neglected.     

Medial unicompartmental knee arthroplasty with Miller-Galante II prosthesis: mid-term clinical and radiographic results

Aim  The purpose of our study was to evaluate retrospectively the mid-term results of the Miller-Galante II (Zimmer, Warsaw, USA) unicondylar knee arthoplasty (UKA). Method  The study included 46 patients with medial UKAs. Mean follow-up time was 7.0 years (range 2.7–13.1 years). Results  Survival rate of the prosthesis was 86.6% (95% CI 73.7–99.6) at 7 years. The mean clinical and functional Knee Society Scores had increased from 51 and 62 points preoperatively to 76 and 93 points (P < 0.001) postoperatively. Five of the 46 knees were revised because of excessive wear of the polyethylene liner, and three due to progression of the osteoarthritis in the lateral compartment of the knee. Conclusion  Survival of this fixed-bearing UKA was not as good as previously reported and polyethylene wear seems to be a more common problem than previously assumed.     

Compensation by reduced L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor responses in a mouse model with reduced gamma-aminobutyric acid type A receptor-mediated synaptic inhibition

L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists increase the threshold for electroshock-induced convulsions. Here, we show that a transgenic mouse line overexpressing cerebellum-restricted gamma-aminobutyric acid type A (GABA(A)) receptor alpha6 subunit in the hippocampal CA1 pyramidal cells (Thy1alpha6 mouse line) exhibits about a 20% increase in the electroshock current intensity inducing tonic hindlimb extension convulsion in 50% of the mice compared with that of their wild-type controls. AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in patch clamp recordings of CA1 pyramidal neurons in hippocampal slices had decreased amplitudes (8.4 +/- 2.2 pA) in the transgenics compared with the wild types (10.3 +/- 2.5 pA) but showed no change in current decay or frequency. Our results suggest that decreased AMPA-mediated neurotransmission might explain the increased threshold for electroconvulsions and warrant further studies on the regulation between various components of inhibition and excitation in neurons.