Factors that influence the assessment of parathyroid graft function

Autogenous parathyroid grafts are used in the treatment of primary and secondary parathyroid hyperplasia and for salvaging normal parathyroid glands removed during thyroid surgery. Placement of the autogenous grafts in the forearm may allow assessment of graft function by comparing the patient's background level of immunoreactive parathyroid hormone (iPTH) with the iPTH value in the antecubital vein above the parathyroid graft. Among patients who on clinical grounds seem to have functioning parathyroid tissue, significant iPTH gradients can be demonstrated in only approximately 80%. Several technical and clinical factors can prevent demonstration of an iPTH gradient in patients who in fact do have functioning parathyroid grafts. Hypercalcemia may suppress iPTH secretion. PTH secretion may be intermittent. High background levels of iPTH due to renal failure may transform a significant numerical gradient for iPTH into an insignificant percentage change in iPTH. It may be technically difficult to obtain blood from the particular vein bearing effluent from the parathyroid graft. The regional specificity of the iPTH assay employed may have an important influence on the magnitude of the apparent iPTH gradient. Knowledge of these factors should maximize the chance of documenting parathyroid graft function.     

The influence of tidal volume on the dynamic variables of fluid responsiveness in critically ill patients

Respiratory-related variabilities in stroke volume and arterial pulse pressure (Delta%Pp) are proposed to predict fluid responsiveness. We investigated the influence of tidal volume (Vt) and adrenergic tone on these variables in mechanically ventilated patients. Cyclic changes in aortic velocity-time integrals (Delta%VTI(Ao), echocardiography) and Delta%Pp (catheter) were measured simultaneously before and after intravascular volume expansion, and Vt was randomly varied below and above its basal value. Intravascular volume expansion was performed by hydroxyethyl starch (100 mL, 60 s). Receiver operating characteristic curves were generated for Delta%VTI(Ao), Delta%Pp and left ventricle cross-sectional end-diastolic area (echocardiography), considering the change in stroke volume after intravascular volume expansion (> or =15%) as the response criterion. Covariance analysis was used to test the influence of Vt on Delta%VTI(Ao) and Delta%Pp. Twenty-one patients were prospectively included; 9 patients (43%) were responders to intravascular volume expansion. Delta%VTI(Ao) and Delta%Pp were higher in responders compared with nonresponders. Predictive values of Delta%VTI(Ao) and Delta%Pp were similar (threshold: 20.4% and 10.0%, respectively) and higher than that of left ventricle cross-sectional end-diastolic area at the appropriate level of Vt. Delta%Pp was slightly correlated with norepinephrine dosage. Delta%Pp increased with the increase in the level of Vt both before and after intravascular volume expansion, contrasting with an unexpected stability of Delta%VTI(Ao). In conclusion, Delta%VTI(Ao) and Delta%Pp are good predictors of intravascular fluid responsiveness but the divergent evolution of these two variables when Vt was increased needs further explanation.     

Health related quality of life (HRQOL) of kidney transplanted patients: variables that influence it

The incidence and prevalence of patients on renal replacement therapy (RRT) who receive a renal transplant are continuously increasing in Spain. At the moment, they are the main group of end-stage renal disease (ESRD) patients in our region (60% of total RRT patients). The aim of the present study was to assess the health related quality of life (HRQOL) of kidney transplanted patients of our region, and to identify socio-demographic and clinical variables that influence it. The intention was also to compare the HRQOL of these patients with that of chronic haemodialysis (HD) patients and of the general population. METHODS: Two hundred and ten kidney transplanted patients and 170 HD patients were evaluated using the Karnofsky performance scale (KPS), sickness impact profile (SIP), and SF-36 Health Survey (SF-36). Socio-demographic and clinical data, including a comorbidity index (CI), were also collected. To compare our patients with the general population we used SF-36 mean scores from an aleatory sample taken from our region. RESULTS: Transplant patients had lower mean scores on SIP dimensions and higher scores on SF-36 dimensions than chronic HD patients. In transplant patients, we found significant differences on SIP and SF-36 scores in gender, educational level, haematocrite and haemoglobin, CI, time since transplantation, and KPS. CONCLUSIONS: The HRQOL of transplant patients is clearly better than that of chronic HD patients and similar to that of the general population. Differences in the HRQOL within transplant patients did not appear to be as a result of patient's age, but rather it would appear to be a consequence of gender, analytic figures, CI, KPS score, time with transplant, and educational level.     

Extracorporeal shockwave lithotripsy for ureterolithiasis in patients with urinary bilharziasis: efficacy and variables that influence treatment outcome

OBJECTIVES: Schistosomiasis affecting the ureter is commonly accompanied by ureteric dilatation with or without ureteric stricture and altered ureteric wall motility that can influence extracorporeal shockwave lithotripsy (ESWL) results. This study attempts to identify variables that may influence the outcome of ESWL in the treatment of ureterolithiasis in patients with urinary bilharziasis. PATIENTS AND METHODS: Forty-three patients with urinary schistosomiasis and ureterolithiasis treated with ESWL were reviewed. The study data include characteristics of patients, stones, urinary tract treated and details of ESWL treatment. RESULTS: Thirty-five patients (81.3%) were stone-free at 3 months. Multivariate analysis with logistic regression identified two significant variables that influenced treatment outcome, namely the presence of ureteric stricture (p = 0.004) and the ESWL voltage (p = 0.003). Ten ureteric strictures were encountered in 9 patients (21%), the majority of these were diagnosed post-ESWL when patients failed to pass well-fragmented stones in spite of pre-ESWL evaluation. CONCLUSIONS: In situ ESWL is a safe and effective first line of treatment for urinary stones in bilharzial ureters. The presence of concomitant bilharzial stricture is a significant variable which affects the treatment outcome. Every effort should be made to rule out and deal with possible complicating factors such as ureteric strictures in the pretreatment period.     

围术期循环容量监测的动态指标及其研究进展

背景大量研究表明围术期加强循环容量监测、目标导向液体治疗（goal-directed fluid therapy,GDT）可以减少术后并发症,改善患者预后。每搏输出量变异度（stroke volume variation,SVV）、脉压差变异度（pialse pressure variation,PPV）、脉搏灌注变异指数（pleth variability index,PVI）、PPV／SVV比值等动态指标可以预测容量反应性,指导患者容量治疗的能力优于静态指标。目的探讨动态参数指导容量治疗的可靠性和影响因素。内容动态指标易受潮气量、血管张力、体位等多种因素影响,而且患者心律失常、非机械通气时动态参数没有应用价值。另外,容量治疗的目标是保证组织灌注和氧供,不能单纯依靠某一参数变化进行评价。因此,应结合患者其他血流动力学参数、相关实验室指标及临床转归等综合判断。趋向动态指标对预测液体治疗效果具有很好的指导意义和广阔的应用前景,其对脑组织等灌注的评估能力仍需进一步研究。     

The healing of freeze-dried rabbit flexor tendon in a synovial fluid environment

Deep flexor tendons from the forepaws of rabbits were removed and cut into two segments, sutured and freeze-dried. About one week later each tendon was placed in a knee joint of the same rabbit from which the tendon had been removed. At one, two, three and six weeks the tendons were retrieved and examined grossly, histologically and by electron microscopy. For comparison a control group using non freeze-dried tendons was also studied. Although there was evidence of central necrosis, superficial healing of the freeze-dried tendons occurred and was presumably due to cells from the synovial fluid.     

Clinico-radiological assessment and their correlation in clubfeet treated with postero-medial soft-tissue release

The controversy regarding the radiographic parameter which best represents the various deformities of clubfoot continues. The aim of our study was to clear up this controversy. Fifty surgically treated (soft-tissue release) congenital clubfeet were studied clinically using Laaveg and Ponseti score and radiologically using twelve different radiographic parameters in weight-bearing AP and lateral views. The talo-calcaneal angle (TCA) in AP and lateral view showed statistically significant correlation with the functional rating, but significant variation in the dimension of the angles among the different functional groups was found with AP angle only. The talo-first metatarsal angle in AP and lateral view averaged 10 degrees and 19 degrees respectively, and showed significant correlation with the functional rating. The talo-navicular subluxation in AP, the calcaneo-fifth metatarsal angle and the first-fifth metatarsal angle in lateral view did not show any significant correlation with function. Talo-calcaneal index averaged 44 degrees in the clubfeet and showed significant correlation. The wide range of parameters representing each of the deformities gives a better radiological assessment of the clubfoot than any single parameter.     

Effect of elevated PEEP on dynamic variables of fluid responsiveness in a pediatric animal model

Background: Previous studies have demonstrated that stroke volume variation (SVV), pulse pressure variation (PPV) and global end‐diastolic volume (GEDV) can be used to predict the response to fluid administration. Currently, little information is available whether application of different levels of positive end‐expiratory pressure (PEEP), especially in infants and neonates, affects their ability to predict fluid responsiveness. The aim of our study was to assess the effect of increasing PEEP levels on the predictive value of SVV, PPV and GEDV with respect to fluid responsiveness. Methods: Stroke volume variation and PPV were monitored continously in 22 anesthetized piglets during changing PEEP levels (5 and 10 cmH₂O) both before and after fluid loading (FL). GEDV was measured by transpulmonary thermodilution; cardiac output and stroke volume (SV) were measured by pulmonary artery thermodilution. A positive response to FL was defined as ≥15% increase in SV. Results: Fluid loading induced significant changes in all hemodynamic variables except of heart rate and systemic vascular resistance. At PEEP 5 cmH₂O, SVV, PPV and GEDV significantly correlated with volume induced percentage change in SV, whereas at PEEP 10 cmH₂O, this correlation was abolished for PPV. As assessed by receiver operating characteristic curve analysis, SVV and GEDV, independent of PEEP level applied, were the best predictors of a positive response to FL [area under the curve: SVV = 0.88; GEDV = 0.80]. Conclusions: In this pediatric animal model, SVV and GEDV were sensitive and specific predictors of fluid responsiveness during increasing PEEP levels.     

Quantitative assessment of glenohumeral translation

Cutaneous electromagnetic position sensors were used to quantify anteroposterior laxity of the shoulder. Forty-three female athletes were tested (27 were soccer players and 16 were swimmers). The athletes had a mean age of 18.8 years (range, 17-24 years), and all were free of shoulder disorders. Dominant and nondominant shoulders were tested. Each shoulder was suspended in 90 degrees abduction and neutral rotation. Serial anteroposterior translations were done manually similar to an anteroposterior drawer examination of the shoulder. The glenohumeral translation for the soccer players was 9.6 mm (range, 5.8-15.1 mm) in the dominant shoulder and 10.7 mm (range, 5.2-16.7 mm) in the nondominant shoulder. The translations in the swimmers were significantly greater at 12.4 mm (range, 8.9-15.9 mm) in the dominant and 13.8 mm (range, 8.8-17.4 mm) in the nondominant shoulders. The mean of the differences between the dominant and nondominant shoulders was 2.1 mm for the swimmers and soccer players. For the soccer players, the range for the side to side differences was 0.1 to 5.3 mm. For the swimmers, the range was 0.1 to 4.3 mm. Finding a clinical device for objective measurement of joint laxity in the shoulder that is accurate, reproducible, noninvasive, and easy to use has been evasive.     

Quantitative assessment of fracture healing

Usually follow-up of the healing process of bone fractures is by subjective assessment of standard X-rays, based on the clinician's personal experience. It is therefore impossible to completely avoid misjudgements in the evaluation of the mechanical stability. Other authors have reported that the mechanical response of bony structures to a knock impulse allows a definitive statement about the stiffness of a fracture. The practicability of computerised sonometry in computer-aided evaluation of the mechanical vibration reaction and the acoustic transmission of sound through osseous structures for assessing stability has been proved in experimental and clinical studies. We designed an animal study that would allow a systematic correlation between the diagnostic investigations in general use. As a main goal, this study tries to correlate sonography with other quantitative techniques, even if they are not used under everyday clinical conditions. Our results show that methods based on direct assessment of the mechanical stability between fracture fragments allow a more exact evaluation of fracture healing. This study helps to classify the results of computerised sonometry together with other diagnostic procedures used for the evaluation of fracture healing, and furthermore provides a basis for clinical interpretation of the findings of a new, non-invasive technique for precise quantitative assessment of fracture healing.     

Assessing the influence of non-treatment variables in a study of outcome from severe head injuries

An evaluation was made of the impact of non-treatment variables on severely injured head trauma patients. The principal findings were: 1) severity of injury was the best predictor of outcome; 2) patient's age had a statistically significant but marginally useful impact on outcome; 3) a regression analysis showed that duration of transport, up to 4 hours, had no impact on outcome; 4) time from accident to intubation had a marginal impact on outcome; and 5) one-way analysis of variance showed that mode of transportation, whether helicopter, ambulance, or other means had no impact on outcome.     

Quantitative assessment of a new preparatory tool for board certification in urology

OBJECTIVE: To analyse the performance of candidates in a Canadian national mock-examination for final-year urology residents with respect to North American speciality examinations in urology. METHODS: In 1997 the Queen's Urology Examination Skills Training Program (QUEST) was established as an annual national mock examination for final-year Canadian urology residents. It consists of a short answer question component and an objective structured clinical examination. During the 5-year period (1997-2001), 91 final-year residents from all 11 Canadian urology residency-training programmes participated in QUEST and the Royal College of Physicians and Surgeons of Canada certifying examinations (RCPSCE); 43 (47%) of candidates also attempted the American Board of Urology part 1 qualifying examinations (ABU 1). Performance on QUEST was correlated with the RCPSCE and ABU 1 in a blinded fashion after submitting QUEST scores to governing bodies. Thresholds were determined to help to predict a candidate's performance on the RCPSCE and ABU 1, based on QUEST scores. RESULTS: There was a moderately close correlation between overall QUEST and RCPSCE performance (r = 0.68, P < 0.001) and a moderate correlation between overall QUEST and ABU 1 performance (r = 0.42, P = 0.005). For the following QUEST scores, the probability of success on the RCPSCE was: < 65%, 67% pass; 66-75%, 80% pass; > 75%, 100% pass (P = 0.002). For ABU 1, QUEST overall score of 80% gave a 69% probability of scoring > or = 70% on ABU 1 (P = 0.003). CONCLUSIONS: QUEST is a moderate predictor of performance on speciality examinations in urology. We consider that the time, effort and expense to maintain QUEST are justified.     

An experimental study of the influence of magnetic fields on soft-tissue wound healing

The influence of magnetized foil strips (Energy-Pak Ltd., Wolfhalden, Switzerland) on soft-tissue healing in the skin of laboratory rats was studied. Linear sutured wounds healing by primary intention have been assessed for tensile strength using Instron tensiometry, and open full-thickness defects healing by secondary intention have been analyzed for collagen content, histologic appearance, and rate of healing. Wounds were covered by the alternate magnetic Energy-Pak foil or by a dummy control. No differences in tensile strength, collagen content, histologic studies, or rate of healing were seen between the treated and control groups.