A decision model to estimate a risk threshold for venous thromboembolism prophylaxis in hospitalized medical patients.

Essentials Low risk patients don't require venous thromboembolism (VTE) prophylaxis; low risk is unquantified. We used a Markov model to estimate the risk threshold for VTE prophylaxis in medical inpatients. Prophylaxis was cost-effective for an average medical patient with a VTE risk of ≥ 1.0%. VTE prophylaxis can be personalized based on patient risk and age/life expectancy. SUMMARY: Background Venous thromboembolism (VTE) is a common preventable condition in medical inpatients. Thromboprophylaxis is recommended for inpatients who are not at low risk of VTE, but no specific risk threshold for prophylaxis has been defined. Objective To determine a threshold for prophylaxis based on risk of VTE. Patients/Methods We constructed a decision model with a decision-tree following patients for 3 months after hospitalization, and a lifetime Markov model with 3-month cycles. The model tracked symptomatic deep vein thromboses and pulmonary emboli, bleeding events and heparin-induced thrombocytopenia. Long-term complications included recurrent VTE, post-thrombotic syndrome and pulmonary hypertension. For the base case, we considered medical inpatients aged 66 years, having a life expectancy of 13.5 years, VTE risk of 1.4% and bleeding risk of 2.7%. Patients received enoxaparin 40 mg day-1 for prophylaxis. Results Assuming a willingness-to-pay (WTP) threshold of $100 000/ quality-adjusted life year (QALY), prophylaxis was indicated for an average medical inpatient with a VTE risk of ≥ 1.0% up to 3 months after hospitalization. For the average patient, prophylaxis was not indicated when the bleeding risk was > 8.1%, the patient's age was > 73.4 years or the cost of enoxaparin exceeded $60/dose. If VTE risk was < 0.26% or bleeding risk was > 19%, the risks of prophylaxis outweighed benefits. The prophylaxis threshold was relatively insensitive to low-molecular-weight heparin cost and bleeding risk, but very sensitive to patient age and life expectancy. Conclusions The decision to offer prophylaxis should be personalized based on patient VTE risk, age and life expectancy. At a WTP of $100 000/QALY, prophylaxis is not warranted for most patients with a 3-month VTE risk below 1.0%.

Evolution of Fabry disease in male patients: the Greek experience.

Fabry disease is a progressive metabolic disorder with a clinical course characterized by different phases and a variety of disease manifestations. The first symptoms generally appear in childhood or early adolescence and are followed by late life-threatening complications involving vascular, renal, cardiac, and cerebral systems. We report the clinical and biochemical characteristics of 16 male patients from 10 unrelated families who represent almost the entire cohort of known Fabry patients in Greece. Despite the presence of early symptoms in almost every patient (mean age at onset of symptoms 15.6 years), the diagnosis was delayed for a mean of about 18 years (mean age of diagnosis 36 years). Patients are currently monitored and the majority (15 out 16 patients) treated with Enzyme Replacement Therapy.

Thyroid hormone modulates the responsiveness of rat aorta to alpha1-adrenergic stimulation: an effect due to increased activation of beta2-adrenergic signaling.

AIM: The ability of the thyroid hormone to increase cardiac output and to lower systemic vascular resistance may provide a novel treatment for cardiovascular diseases. Therefore, understanding the mechanisms of thyroid hormone action on the heart and peripheral vasculature could be of clinical importance. We previously found that thyroid hormone modulates the alpha1-adrenergic effect on vascular reactivity of rat aortas. In the present study we further investigated possible mechanisms of this response. METHODS: Hyperthyroidism was induced on Wistar-Kyoto male rats with L-Thyroxine, (THYR) treatment for two weeks, N.=18 while untreated rats used as controls (NORM), N.=16. The thoracic aorta was dissected and cut into rings that were suspended in an isolated organ bath with Krebs-Henseleit buffer. Maximal tension, Tmax, in g was measured in response to Potassium Chloride (KCl) and Phenylephrine (PE) in rings in the presence of Ritodrine, a beta-2 agonist (NORM-RITO, N:=8, THYR-RITO, N.=9), or in the absence of Ritodrine (THYR, N.=9, NORM, N.=8). RESULTS: With KCL, Tmax was not different between the THYR, NORM, NORM-RITO, and THYR-RITO groups. With PE, there was a difference in Tmax between NORM-RITO and NORM, 0.66 (0.056) g vs 1.00 (0.066) g, P<0.05 and THYR and NORM, 0.75 (0.055) g vs 1.00 (0.066) g, P<0.05. No significant difference was observed between THYR-RITO AND THYR. Furthermore, Relax % was not significantly different between the NORM and the THYR, NORM-RITO, and THYR-RITO groups, 64.5%(3.7) vs 67.3%(6.7), 73.5% (4.3) and 81.8 %(4.7), P>0.05. CONCLUSIONS: PE induced vasoconstriction in isolated rat aortic rings was reduced after both ritodrine and thyroxine treatment. However, co-administration of thyroid hormone and ritodrine did not result in a synergistic reduction of PE induced vasoconstriction. Thus, thyroxine may modulate the alpha1-adrenergic vascular responsiveness by enhancing beta2-adrenergic stimulation.

Five-year survival in comparable HD and PD patients: one center's experience.

Several studies have yielded conflicting results regarding morbidity and mortality in peritoneal dialysis (PD) and hemodialysis (HD) patients. We performed a retrospective analysis in end-stage renal disease (ESRD) patients in our department, who were equally distributed between HD and PD, in order to compare 5-year survival probabilities and hospitalization rates in the two modalities. Of the total 94 new ESRD patients who initiated dialysis in our department from January 1995 to December 2000, 48 were allocated to PD and 46 to HD. All patients were followed up for five years. There were no significant differences regarding demographics and serious co-morbidities upon dialysis initiation between HD and PD patients. Unadjusted 5-year survival probability in as-treated analysis was higher in PD patients (0.79 vs 0.6, p=0.04), whereas there was no significant difference in intent-to-treat analysis between HD and PD patients (p=0.5). Hospitalization rates were similar in both modalities. Despite the small number of patients included in our study, it seems that when HD and PD are both available in one department they have equivalent results regarding morbidity and mortality rates. Therefore we suggest that, when possible, PD and HD should be equally offered to all ESRD patients.

Development, survival, and reproduction of the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae) at different constant temperatures.

Development, survival, and reproduction of the predatory mite Kampimodromus aberrans Oudemans were studied at constant temperatures in the range from 15 to 35 degrees C under laboratory conditions. Larval developmental rate for both males and females increased gradually from 15 to 35 degrees C and decreased at higher temperatures. Lactin's nonlinear model described with adequate accuracy the relationship between developmental rate and temperature. The model predicted that lower and upper threshold temperatures for preimaginal development ranged from 9.8 to 11.8 degrees C and from 37.2 to 39.8 degrees C, respectively. The intrinsic rate of population increase (rm) at the different temperatures ranged from 0.0442 to 0.1575, with the highest value recorded at 25 degrees C. At 33 degrees C a negative rm value was estimated. The rm values determined at different temperatures were fitted to Lactin's nonlinear model, and the lower and upper threshold and the optimal temperatures for population increase were 10.5, 32.4, and 27.6 degrees C, respectively. These data indicate that K. aberrans may be better adapted to intermediate temperatures around 27 degrees C and, therefore, could be a useful biocontrol agent of spider mites during spring and early summer when such temperatures are prevalent in northern Greece. The results could also be useful in developing a population model for K. aberrans under field conditions.

Effectiveness of aluminum hydroxide timing administration in relation to meals in controlling hyperphosphatemia in dialysis patients.

Phosphate binder compounds contribute to the control of hyperphosphatemia in hemodialysis (HD) patients. However, the most effective schedule of administration of phosphate binders in relation to meals is not well documented. We examined the effectiveness of aluminum hydroxide intake as the sole phosphate binder in relation to meals. Eighty-five patients on regular HD (45 male, 40 female), age 21-72 years, with a duration of 6-216 months HD participated in the study. In all patients, phosphate binders were discontinued for a one month period. Thereafter, and according to the protocol, all patients were advised to take aluminum hydroxide [Al(OH)3 ] 30 min before, during and 30 min after meals for 3 periods of one month each, in a random order. One month washout period preceded the periods of Al(OH)3 ingestion. When Al(OH)3 was administered 30 min prior to the meals, serum phosphate decreased by 7.0% (0.59 mg/dL), while when administrated with or 30 min after meals, it decreased statistically significantly by 28.5% (2.08 mg/dL), and 16% (1.29 mg/dL) respectively. Our results suggest that the efficacy of Al(OH)3 to bind phosphate salts and thus to prevent the hyperphosphatemia in HD patients is higher when this drug is taken with meals.

Effect of cyclosporine, mycophenolate mofetil, and their combination with steroids on apoptosis in a human cultured monocytic U937 cell line.

Transplant patient plasma produces an increased rate of mononuclear cell apoptosis despite a normal serum creatinine value. Immunosuppressive medications may be one factor that causes an altered apoptotic pattern. We evaluated the in vitro effects of various doses of cyclosporine, mycophenolate mofetil, and steroids on apoptosis of a cultured human monocytic U937 cell line, using estimates by fluorescence microscopy and annexin V assays. Increasing cyclosporine concentrations (100 to 800 ng/mL) progressively increased apoptosis rates (16% to 32%). The combination of steroid (0.01 microg/mL) and cyclosporine increased the apoptosis rate to 45%. Mycophenolate mofetil alone (0.3 microg/mL) led to an apoptosis rate of 34%. Therapeutic levels of mycophenolate mofetil from 3 to 7 microg/mL led to apoptosis rates from 56% to 67%. The combination of cyclosporine, steroid, and mycophenolate mofetil increased the rate of apoptosis to 95%. Immunosuppressive therapy may contribute to the high rate of apoptosis observed among mononuclear cells of transplanted patients. This effect may alter patient susceptibility to infections and contribute to a unique mechanism of immunosuppression.

Cardiovascular phenotyping of fetal mice by noninvasive high-frequency ultrasound facilitates recovery of ENU-induced mutations causing congenital cardiac and extracardiac defects.

As part of a large-scale noninvasive fetal ultrasound screen to recover ethylnitrosourea (ENU)-induced mutations causing congenital heart defects in mice, we established a high-throughput ultrasound scanning strategy for interrogating fetal mice in utero utilizing three orthogonal imaging planes defined by the fetus' vertebral column and body axes, structures readily seen by ultrasound. This contrasts with the difficulty of acquiring clinical ultrasound imaging planes which are defined by the fetal heart. By use of the three orthogonal imaging planes for two-dimensional (2D) imaging together with color flow, spectral Doppler, and M-mode imaging, all of the major elements of the heart can be evaluated. In this manner, 10,091 ENU-mutagenized mouse fetuses were ultrasound scanned between embryonic days 12.5 and 19.5, with 324 fetuses found to die prenatally and 425 exhibiting cardiovascular defects. Further analysis by necropsy and histology showed heart defects that included conotruncal anomalies, obstructive lesions, and shunt lesions as well as other complex heart diseases. Ultrasound imaging also identified craniofacial/head defects and body wall closure defects, which necropsy revealed as encephalocele, holoprosencephaly, omphalocele, or gastroschisis. Genome scanning mapped one ENU-induced mutation associated with persistence truncus arteriosus and holoprosencephaly to mouse chromosome 2, while another mutation associated with cardiac defects and omphalocele was mapped to mouse chromosome 17. These studies show the efficacy of this novel ultrasound scanning strategy for noninvasive ultrasound phenotyping to facilitate the recovery of ENU-induced mutations causing congenital heart defects and other extracardiac anomalies.

Hemodialysis for patients bleeding or at risk for bleeding, can be simple, safe and efficient.

AIM: Hemodialysis for patients bleeding or at risk for bleeding requires special modalities of treatment that are difficult to perform without potential side effects. A simple, safe and adequate method may be applied. METHODS: A modified way of extracorporeal circuit preparation, which focuses on minimizing the blood-air interface and negligible saline flushing of 50 ml/h, is applied for a maximum of 3-hour session with routine (not one-to-one) nursing attendance. Data from 16,954 sessions performed with patients bleeding or at risk for bleeding (15,730 retrospectively and 1,224 prospectively collected) were analyzed. RESULTS: Cumulative failure of treatment, as defined by clotting of the extracorporeal circuit requiring termination of the procedure or replacement of the clotted part, was not more than 5% as expected for anticoagulation-free hemodialysis. For the prospectively recorded sessions, blood flow was 234 +/- 30 ml/min with less than 250 ml/min in 42.4% of the sessions. Native blood access was used in 426 (34.8%), double-lumen catheter in 798 (65.2%), 42 were isolated ultrafiltration sessions and 64 blood, 21 plasma, 9 platelet units were transfused. Post/pre urea ratio was 0.50 +/- 0.12. Logistic regression showed that among the following: duration of the session, type of dialysis, ultrafiltration rate, hematocrit, number of platelets, serum total protein, transfusions, blood flow and type of access, only blood flow significantly affected failure incidence (coefficient B = -0.041, exp(B) = 0.96, p = 0.04). No complications due to treatment were noted. CONCLUSION: In patients with active, or at risk for, bleeding, hemodialysis without systemic anticoagulation can be adequately and safely performed almost as a routine session.

Twenty-year evaluation of meniscal bearing and rotating platform knee replacements.

Clinical results of the initial cemented and cementless series of 373 New Jersey Low Contact Stress total knee replacements in 282 patients surviving at least 10 years were analyzed using a strict knee scoring scale. The study showed excellent, good, fair, or poor results in 68.1%, 29.8%, 2.1%, or 0% of primary posterior cruciate-retaining meniscal bearing knee replacements, 46.7%, 53.3%, 0%, or 0% results in primary cemented rotating platform knee replacements, and 68.1%, 29.8%, 2.1%, or 0% results in primary cementless rotating platform knee replacements, respectively. Radiographic evaluation at minimum 10-year followup showed stable fixation of all components, no gross migration but significant osteolysis requiring bearing exchange and bone grafting in three cementless rotating platform knee replacements (1.8%) in three patients who underwent previous surgeries at an average of 10.2 years from the index surgery. Survivorship of the patients who underwent primary cementless posterior cruciate-retaining meniscal bearing knee replacements with an end point of revision for any mechanical reason was 97.4% at 10 years and 83% at 16 years; using an end point of a poor clinical knee score the survivorship was 98.9% at 10 years and at 16 years. Survivorship of the patients who underwent primary cemented rotating platform knee replacements with end points of revision for any mechanical reason or a poor clinical knee score was 97.7% at 10 years and at 20 years. Survivorship of the patients who underwent cementless rotating platform knee replacements with end points of revision for any mechanical reason or a poor clinical knee score was 98.3% at 10 years and at 18 years.

Laparoscopic placement of the Tenckhoff catheter for peritoneal dialysis.

Continuous ambulatory peritoneal dialysis catheters can be inserted by open laparotomy as well as by laparoscopy. A prospective randomized study was scheduled to investigate the results of the laparoscopic versus open laparotomy technique for placement of continuous ambulatory peritoneal dialysis catheters. Fifty patients were enrolled and randomly allocated into two groups of 25 patients each. Group A underwent continuous ambulatory peritoneal dialysis catheter placement via the open laparotomy technique. In 22 patients, catheters were inserted via midline incision, and in 3 patients with histories of previous catheterization, a paramedian incision was used. Continuous ambulatory peritoneal dialysis was started 24 to 48 hours later. Group B underwent laparoscopic placement of the catheter with fixation into the pelvis and suture closure of the port wounds. In 21 patients, this catheter placement was the first such placement, and in 4 patients, a previous catheter had been inserted by the open technique and removed for dysfunction. Continuous ambulatory peritoneal dialysis was started at the end of the procedure. The mean operative time was 22 minutes in group A and 29 minutes in group B (P < 0.001). Fluid leakage was observed in eight patients in group A, but in no patients in group B (P < 0.005). Peritonitis occurred in five patients in group A and in three patients in group B (P > 0.1). Tip migration occurred in five patients in group A and no patients in group B (P < 0.005). In group B, two patients underwent a simultaneous cholecystectomy and one underwent incisional hernia repair. Laparoscopic placement of a Tenckhoff catheter leads to better function than does the open procedure; it allows immediate start of dialysis without fluid leakage and permits simultaneous performance of other laparoscopic procedures.

Digital color restoration of old paintings.

Physical and chemical changes can degrade the visual color appearance of old paintings. Five digital color restoration techniques, which can be used to simulate the original appearance of paintings, are presented. Although a small number of color samples is employed in the restoration procedure, simulation results indicate that good restoration quality can be attained.

Effect of L-carnitine supplementation on lipid parameters in hemodialysis patients.

It has been reported that cumulative carnitine losses through dialysis membranes may worsen hyperlipidemia during long-term hemodialysis. However, carnitine supplementation has not shown a consistent beneficial response. We undertook the present study to determine if there is any hypolipidemic effect of L-carnitine on Greek dialysis patients in concert with the dialysate buffer composition (acetate or bicarbonate). A total of 28 patients (16 male, 12 female), mean age 43 years (range 21-61), with end-stage renal disease on maintenance hemodialysis for a mean period of 25 months (range 7-84) were studied. The dialysis schedule was 4 h, 3 times/week using cuprophane hollow-fiber dialyzers and acetate (n = 14) or bicarbonate (n = 14) dialysate. In all patients L-carnitine (5 mg/kg body weight) was infused intravenously 3 times/week at the end of each hemodialysis session. Blood samples for carnitine and lipid determinations were obtained before treatment, and 3 and 6 months following treatment. Even though L-carnitine did not modify most of the serum lipid levels, a significant decrease in serum triglycerides was evident in the whole group of patients (from 225 +/- 76 to 201 +/- 75 mg/dl, p = 0.03). Furthermore, L-carnitine could decrease serum triglycerides only in hypertriglyceridemic patients (from 260 +/- 64 to 226 +/- 82 mg/dl, p < 0.05). L-Carnitine resulted in a reduction of serum triglycerides in both patients on bicarbonate and on acetate dialysis, while there were no significant differences in the changes of lipid parameters after L-carnitine between the two groups of hemodialysis patients. We conclude that relatively low doses of L-carnitine supplementation could contribute to the management of some hypertriglyceridemic hemodialysis patients.

Combined saphenous vein with free flap reconstruction in the treatment of carotid stenosis.

Revascularization for arterial stenosis in varied anatomic sites exposed to therapeutic radiation has been well described. In most circumstances, symptomatic end organ ischemia has been the indication for surgical intervention. We report the case of a patient who had symptomatic carotid stenosis 40 years after having ipsilateral neck dissection with radiation therapy. We did a saphenous vein graft interposition and free flap reconstruction of the overlying damaged skin.

Effects of conventional vs. low-molecular-weight heparin on lipid profile in hemodialysis patients.

Cardiovascular disease is one of the major causes of death in hemodialysis patients and seems to be related, at least in part, to lipid abnormalities. It has been suggested that in these patients low-molecular-weight heparin (LMWH) is superior to conventional heparin because it causes less side effects and has beneficial effects on lipid parameters. Our study was carried out to examine the long-term effects of the replacement of conventional heparin by LMWH on the lipoprotein profile in a large group of hemodialysis patients. A total of 76 patients aged 15-61 years receiving hemodialysis for 48 (range 10-169) months were studied. In all patients administration of LMWH was introduced in doses of 2,500-5,000 anti-factor Xa units for 12 months. Then, we randomly switched half of the patients back to conventional heparin for another 12 months, while the remaining patients continued to receive LMWH for 12 months. In the whole group of patients the use of LMWH instead of conventional heparin was followed by a significant decrease in serum total cholesterol, triglyceride and apoprotein B levels. The continued use of LMWH for another 12 months in half of the patients was followed by a further significant improvement in the lipid profile. In contrast, no significant changes in serum lipid parameters were observed in patients switched back to conventional heparin. In conclusion, the use of LMWH instead of conventional heparin for anticoagulation during hemodialysis is followed by an improvement in lipid profile, which is evident only after long-term treatment.

Long-term effects of low molecular weight heparin on lipid parameters in hemodialysis patients.

OBJECTIVE: The long-term effects of the replacement of conventional heparin by low-molecular weight heparin (LMWH) on lipid parameters were examined in a large group of hemodialysis patients. EXPERIMENTAL DESIGN: One-year prospective investigation. SETTING: Renal units. PATIENTS: A total of 93 patients aged 12-63 years old receiving hemodialysis for 51 (1-172) months were studied. None of the patients had primary hyperlipidemia, diabetes mellitus, or other secondary causes of dyslipidemia. INTERVENTIONS: In all patients administration of LMWH was introduced in doses 2500-5000 units. MEASURES: Baseline values of lipoprotein profile prior to the intervention were compared with results obtained after 3, 6 and 12 months of LMWH. RESULTS: During of LMWH treatment a small but statistically significant decrease of total and HDL cholesterol (from 200 +/- 45 mg/dl to 185 +/- 42 mg/dl, p < 0.01, and from 45 +/- 11 mg/dl to 42 +/- 10 mg/dl, p < 0.05, respectively), as well as Apo B (from 128 +/- 36 mg/dl to 121 +/- 35 mg/dl, p < 0.001) was noticed. Moreover, triglycerides decreased significantly (from 175 +/- 73 mg/dl to 146 +/- 62 mg/dl, p < 0.001). The beneficial effects of LMWH were more pronounced in patients with dyslipidemia (total cholesterol > 200 mg/dl, or triglycerides > 200 mg/dl) before the replacement of conventional heparin. CONCLUSION: The long-term use of LMWH instead of conventional heparin for anticoagulation during dialysis has beneficial effects on the lipoprotein profile, especially in patients with dyslipidemia.

Idiopathic pulmonary hemorrhage in infancy. Clinical features and management with high frequency ventilation.

STUDY OBJECTIVES: To describe the clinical characteristics of infants with severe acute pulmonary hemorrhage and the effects of mechanical ventilation on gas exchange. SETTING: Tertiary care pediatric ICU in a university hospital. PATIENTS AND DESIGN: Case records of patients with severe acute pulmonary hemorrhage from January 1992 to July 1995 were reviewed. Acute pulmonary hemorrhage was defined as hemoptysis and/or epistaxis or blood obtained from endotracheal tube which could not be attributed to cardiac or vascular malformation, infectious process, or known trauma. INTERVENTIONS: Patients were initially managed with conventional ventilation. High frequency ventilation (HFV) was utilized when hypoxemia (PaO2/PAO2 < 0.2) and/or respiratory acidosis (PaCO2 > or = 60 mm Hg with pH < 7.25) persisted. MEASUREMENTS AND RESULTS: Six African-American male infants from Detroit, with a median age 2.3 months, presented with severe acute pulmonary hemorrhage. Chest radiographs showed diffuse bilateral infiltrates or opacification with a normal sized heart. All infants were managed with HFV, four by oscillation and two by jet. The indications for HFV were persistent hypoxemia (2), respiratory acidosis (1), and a combination of both (3). There was an improvement in pH and PaCO2, and a decreased need for oxygen 6 and 24 h after initiating HFV. PaO2/PAO2 and oxygenation index showed a tendency toward improvement. All infants survived, and there were no complications. No cause for pulmonary hemorrhage was found in any of the infants. CONCLUSIONS: Idiopathic acute pulmonary hemorrhage is a potentially life-threatening disorder encountered among inner-city infants. HFV is highly effective and safe in rapidly reversing the severe oxygenation and ventilation deficits in this setting.

Predicting outcome in children with severe acute respiratory failure treated with high-frequency ventilation.

OBJECTIVES: a) To demonstrate the effect of high-frequency ventilation on gas exchange in children with severe acute respiratory failure unresponsive to conventional ventilation; b) to identify patients at high risk of death early after institution of high-frequency ventilation. SETTING: Tertiary care pediatric intensive care unit in a university hospital. DESIGN: A cross-sectional, observational study with factorial design. PATIENTS: Thirty-one patients with severe acute respiratory failure defined as a Pao2/F1o2 of < 150 torr (< 20 kPa) with a positive end-expiratory pressure of > or = 8 cm H2O and/or Paco2 of > 60 torr (> 8 kPa) with an arterial pH < 7.25. INTERVENTIONS: Patients received either high-frequency oscillation or jet ventilation if respiratory failure was unresponsive to conventional ventilation and if the underlying disease process was deemed reversible. MEASUREMENTS AND MAIN RESULTS: Thirty-one children were managed with high-frequency ventilation, 11 children with jet and 20 children with oscillator. Arterial blood gases and level of ventilatory support were recorded before and at 6, 24, 48, 72, and 96 hrs after institution of high-frequency ventilation. There was an improvement in an arterial pH, Paco2, Pao2, and Pao2/FID2 6 hrs after institution of high-frequency ventilation (p < .01). This improvement, along with decreased need for oxygen, was sustained through the subsequent course. Twenty-three (74%) of 31 children treated with high-frequency ventilation survived. Survivors showed an increase in an arterial pH, Pao2, Pao2/FIO2, and a decrease in Paco2 within 6 hrs, whereas nonsurvivors did not. Oxygenation index was the best predictor of outcome. A combination of an initial oxygenation index of > 20 and failure to decrease the oxygenation index by > 20% by 6 hrs after initiation of high-frequency ventilation predicted death with 88% (7/8) sensitivity and 83% (19/23) specificity, with an odds ratio of 33 (p = .0036, 95% confidence interval 3-365). CONCLUSIONS: In patients with potentially reversible underlying diseases resulting in severe acute respiratory failure that is unresponsive to conventional ventilation, high-frequency ventilation improves gas exchange in a rapid and sustained fashion. The magnitude of impaired oxygenation and its improvement after high-frequency ventilation can predict outcome within 6 hrs.

Lipid parameters including lipoprotein (a) in patients undergoing CAPD and hemodialysis.

OBJECTIVE: Dyslipidemia possibly contributes to the vascular complications commonly afflicting uremic patients. Lipoprotein (a) [Lp(a)] has been identified as an independent risk factor for atherosclerotic vascular disease. The aim of our study was to compare lipidparameters, including Lp(a), between hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: A cross-sectional study. SETTING: University Medical Center. PARTICIPANTS: Forty CAPD and 40 HD patients carefully matched for age, sex, body mass index (BMI), smoking habits, and duration of dialysis were studied. A group of 40 healthy individuals matched for age, sex, BMI, and smoking habits was used as control. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Serum lipid parameters and atherogenic risk ratios were the main outcome measures. RESULTS: Both groups of dialysis patients had increased serum triglycerides and decreased levels of ApoA1 and HDL cholesterol compared to controls. Moreover, the risk ratios total cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol were significantly higher, and the ratio ApoA1/ApoB was significantly lower in both groups of patients in comparison to the normal subjects. Both groups of dialysis patients exhibited decreased ratios of LDL cholesterol/ApoB and HDL cholesterol/ApoA1, suggesting the presence of compositional lipoprotein changes. CAPD patients had a more atherogenic lipid profile compared to HD patients, since they exhibited higher levels of total and LDL cholesterol, of ApoB as well as of the ratios total cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol, and lower levels of the ratio ApoA1/ApoB compared to HD patients. Both groups of dialysis patients had increased serum Lp(a) levels. Even though CAPD patients had higher serum Lp(a) levels than HD patients, the differences between these two groups were only marginally statistically significant (p = 0.056 by Mann-Whitney U-test). Uremic dyslipidemia was positively correlated with serum albumin levels in both groups of patients. CONCLUSION: CAPD patients exhibit a more atherogenic lipid profile than that of HD patients. The marked disturbances in Lp(a) levels may further increase the vascular risk in both groups of patients.

Titanium nitride ceramic film against polyethylene. A 48 million cycle wear test.

Wear is a major late complication of total joint arthroplasty, particularly for younger, active patients. Many patients could produce > 40 million motion cycles after joint replacement. Based on current experience and testing, typical joint prostheses are likely to wear out, and need revision in such patients. One problem is degradation of the metal (counterface) surface. A harder, more abrasion resistant, counterface surface is needed. This study evaluated the long-term wear of the titanium nitride ceramic film against ultra high molecular weight polyethylene. In this test, 4 47-mm femoral cups with a polished 8-micron-thick titanium nitride coating were run against 4-mm-thick metal-backed polyethylene bearings machined from GUR415 extruded rod in water at 37 degrees C at 5 Hz and a 2200-N fluctuating load. Wear of the counterface and bearing were extremely low. The average maximum reduction in thickness of the polyethylene was < 0.02 mm, and < 2 microns in the ceramic film. The average polyethylene wear rate was only approximately 2% of that found in a similar test using 32-mm cobalt chromium femoral heads. The titanium nitride-polyethylene couple has great potential as a lifetime bearing combination.