The '6W' multidimensional model of care trajectories for patients with chronic ambulatory care sensitive conditions and hospital readmissions.

OBJECTIVES: To synthesize concepts and approaches related to the analysis of patterns or processes of care and patient's outcomes into a comprehensive model of care trajectories, focusing on hospital readmissions for patients with chronic ambulatory care sensitive conditions (ACSCs). STUDY DESIGN: Narrative literature review. METHODS: Published studies between January 2000 and November 2017, using the concepts of 'continuity', 'pathway', 'episode', and 'trajectory', and focused on readmissions and chronic ACSCs, were collected in electronic databases. Qualitative content analysis was performed with emphasis on key constituents to build a comprehensive model. RESULTS: Specific common constituents are shared by the concepts reviewed: they focus on the patient, aim to measure and improve outcomes, follow specific periods of time and consider other factors related to care providers, care units, care settings, and treatments. Using these common denominators, the comprehensive '6W' multidimensional model of care trajectories was created. Considering patients' attributes and their chronic ACSCs illness course ('who' and 'why' dimensions), this model reflects their patterns of health care use across care providers ('which'), care units ('where'), and treatments ('what'), at specific periods of time ('when'). CONCLUSIONS: The '6W' model of care trajectories could provide valuable information on 'missed opportunities' to reduce readmission rates and improve quality of both ambulatory and inpatient care.

Noise-induced hearing loss and combined noise and vibration exposure.

BACKGROUND: While there is a wide body of literature addressing noise-induced hearing loss (NIHL) and hand-arm vibration syndrome (HAVS) independently, relatively few studies have considered the combined effects of noise and vibration. These studies have suggested an increased risk of NIHL in workers with vibration white finger (VWF), though the relationship remains poorly understood. AIMS: To determine whether hearing impairment is worse in noise-exposed workers with VWF than in workers with similar noise exposures but without VWF. METHODS: The Quebec National Institute of Public Health audiometric database was used in conjunction with work-related accident and occupational diseases data from the Quebec workers' compensation board to analyse differences in audiometry results between vibration-exposed workers in the mining and forestry industries and the overall source population, and between mining and forestry workers with documented VWF and those without VWF. The International Organization for Standardization (ISO) 7029 standards were used to calculate hearing loss not attributable to age. RESULTS: 15751 vibration-exposed workers were identified in an overall source population of 59339. Workers with VWF (n = 96) had significantly worse hearing at every frequency studied (500, 1000, 2000 4000 Hz) compared with other mining and forestry workers without VWF. CONCLUSIONS: This study confirms previous findings of greater hearing loss at higher frequencies in workers with VWF, but also found a significant difference in hearing loss at low frequencies. It therefore supports the association between combined noise and hand-arm vibration (HAV) exposure and NIHL.

The IVAIRE project--a randomized controlled study of the impact of ventilation on indoor air quality and the respiratory symptoms of asthmatic children in single family homes.

UNLABELLED: A randomized controlled trial was carried out to measure the impact of an intervention on ventilation, indoor air contaminants, and asthma symptoms of children. Eighty-three asthmatic children living in low-ventilated homes were followed over 2 years. Several environmental parameters were measured during the summer, fall, and winter. The children were randomized after Year 1 (43 Intervention; 40 Control). The intervention included the installation of either a Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV). During the fall and winter seasons, there was a significant increase in the mean ventilation rate in the homes of the intervention group. A statistically significant reduction in mean formaldehyde, airborne mold spores, toluene, styrene, limonene, and α-pinene concentrations was observed in the intervention group. There was no significant group difference in change in the number of days with symptoms per 14 days. However, there was a significant decrease in the proportion of children who experienced any wheezing (≥1 episode) and those with ≥4 episodes in the 12-month period in the intervention group. This study indicates that improved ventilation reduces air contaminants and may prevent wheezing. Due to lack of power, a bigger study is needed. PRACTICAL IMPLICATIONS: Positive findings from this study include the fact that, upon recruitment, most of the single family homes with asthmatic children were already equipped with a mechanical ventilation system and had relatively good indoor air quality. However, the 8-h indoor guideline for formaldehyde (50 µg/m3) was frequently exceeded and the ventilation rates were low in most of the homes, even those with a ventilation system. Both ERVs and HRVs were equally effective at increasing air exchange rates above 0.30 ACH and at preventing formaldehyde concentrations from exceeding the 50 µg/m3 guideline during the fall and winter seasons. Furthermore, the ERVs were effective at preventing excessively low relative humidities in the homes. Based on observed difference of risk, intervention to increase ventilation in five sample homes and children would prevent 1 home to exceed the indoor air long-term formaldehyde guideline and prevent 1 asthmatic child experiencing at least one episode of wheezing over a year.

Detection of renal artery stenosis: prospective comparison of captopril-enhanced Doppler sonography, captopril-enhanced scintigraphy, and MR angiography.

OBJECTIVE: The objective of our study was to compare the value of captopril-enhanced Doppler sonography, captopril-enhanced renal scintigraphy, and gadolinium-enhanced MR angiography for detecting renal artery stenosis. SUBJECTS AND METHODS: Forty-one patients with suspected renovascular hypertension were prospectively examined with captopril-enhanced Doppler sonography, captopril-enhanced renal scintigraphy, gadolinium-enhanced MR angiography, and catheter angiography. The sensitivity and specificity of each technique for detecting renal artery stenosis measuring 50% or greater and 70% or greater were compared using the McNemar test. Positive and negative predictive values were estimated for populations with 5% and 30% prevalence of renal artery stenosis. Kappa values for interobserver agreement were assessed for both gadolinium-enhanced MR angiography and catheter angiography. RESULTS: For detecting renal artery stenosis measuring 50% or greater, the sensitivity of gadolinium-enhanced MR angiography (96.6%) was greater than that of captopril-enhanced Doppler sonography (69%, p = 0.005) and captopril-enhanced renal scintigraphy (41.4%, p = 0.001). No significant difference in specificity was observed among modalities. For renal artery stenosis measuring 50% or greater, positive and negative predictive values were respectively 62% and 86% for captopril-enhanced Doppler sonography, 49% and 76% for captopril-enhanced renal scintigraphy, and 53% and 98% for gadolinium-enhanced MR angiography. Interobserver agreement was high for both gadolinium-enhanced MR angiography (kappa = 0.829) and catheter angiography (kappa = 0.729). CONCLUSION: Gadolinium-enhanced MR angiography is the most accurate noninvasive modality for detecting renal artery stenosis greater than or equal to 50%. The use of captopril-enhanced Doppler sonography in combination with gadolinium-enhanced MR angiography for identifying renal artery stenosis needs to be evaluated with a cost-effectiveness analysis.

Percutaneous revascularization of the renal arteries: predictors of outcome.

PURPOSE: To identify predictors of clinical outcome after percutaneous revascularization of the renal arteries. MATERIALS AND METHODS: In 63 patients, the therapeutic response was retrospectively assessed after percutaneous revascularization of the renal arteries indicated for hypertension (41.3%), renal failure (4.8%), or both (53.9%). All patients underwent percutaneous transluminal renal angioplasty, complemented by stent insertion in 30 patients. The authors analyzed the role of clinical and imaging factors, including scintigraphy, Doppler sonography, and angiography for predicting clinical success. RESULTS: In the hypertensive population, there were three cures (5.6%), 26 improvements (48.1%), and 25 failures (46.3%). Among patients with renal insufficiency, 12 were improved (37.5%), 11 were stabilized (34.4%), and nine deteriorated (28.1%). Predictors of favorable outcome for hypertension were shorter duration of hypertension, higher diastolic blood pressure, fibromuscular dysplasia, abnormal Doppler study, higher percentage of angiographic stenosis, and lower grade of aortic atheromatous disease. Predictors of favorable outcome for renal failure were nondiabetic status, abnormal Doppler study, and higher percentage of angiographic stenosis. Abnormal Doppler and scintigraphic examinations predicted successful treatment of hypertension in 60% and 53.8% of cases, respectively, and renal insufficiency in 85% and 60% of cases, respectively. CONCLUSION: Clinical and angiographic variables were the best predictors of therapeutic success for hypertension. Doppler sonography was useful in patients with renal failure.

Management of IgA nephropathy: evidence-based recommendations.

The condition known as IgA nephropathy was first identified when Berger observed mesangial staining for IgA in healthy patients with isolated hematuria. These patients often presented with recurrent synpharyngitic hematuria or less frequently with asymptomatic microscopic hematuria and proteinuria. Although initially considered benign, we now recognize it as a common cause of end-stage renal failure. The overall prognosis may be better than suggested in the literature, as patients with mild asymptomatic hematuria are often not biopsied and, therefore, frequently are not included in published articles. We reviewed prospective and retrospective adult studies published after 1976 and analyzed them to produce evidence-based recommendations. Patients with proteinuria over 3 g/day, mild glomerular changes only, and preserved renal function (creatinine clearance over 70 ml/min) should be treated with prednisone. Steroids reduce proteinuria (grade B recommendation) and stabilize kidney function (grade C). The combination of cyclophosphamide, dipyridamole and warfarin should not be used (grade A), nor should cyclosporine A (grade B). In patients with progressive disease (creatinine clearance of less than 70 ml/min), fish oil should be given (grade B). A tonsillectomy could reduce proteinuria and hematuria in those patients with recurrent tonsillitis (grade D). Those with hypertension should be treated promptly with an angiotensin-converting enzyme inhibitor (grade B).

Detection of renal artery stenosis with Doppler sonography before and after administration of captopril: value of early systolic rise.

OBJECTIVE: The goal of this study was to assess the value of quantitative and qualitative analysis of the early systolic rise on Doppler waveforms obtained before and after administration of captopril in patients suspected of having renal artery stenosis. SUBJECTS AND METHODS: Seventy-one hypertensive patients (135 kidneys) were studied with transrenal Doppler sonography. Ninety-six kidneys were studied again after administration of captopril. All patients also underwent renal angiography. All Doppler studies were independently reviewed by two observers. Specific criteria for Doppler waveform patterns that were applied in the detection of renal artery stenosis included acceleration, acceleration time of early systolic rise, differential velocity of systolic rise, and resistive index. These criteria were then correlated with angiography, and receiver operating characteristic curves were generated. RESULTS: On the basis of waveform pattern recognition. Doppler sonograms obtained before administration of captopril had a sensitivity of 81% and a specificity of 98% for the detection of renal artery stenosis greater than or equal to 50%. Sensitivity of Doppler sonography obtained after administration of captopril was 100%, and specificity was 100%. For renal artery stenosis greater than or equal to 70%, sensitivity was 94% and specificity was 89% before administration of captopril. The area under the receiver operating characteristic curve for the acceleration criterion was significantly larger after administration of captopril (p = .009) for the detection of renal artery stenosis greater than or equal to 50%. After captopril administration, an acceleration threshold value of 440 cm/sec2 for early systolic rise was associated with a sensitivity of 100% and a specificity of 94% for the detection of renal artery stenosis greater than or equal to 50%. CONCLUSION: Doppler sonography of the renal arteries performed before administration of captopril appears to be an excellent screening tool in the detection of severe stenosis (> or = 70%). Administration of captopril improves the detection of renal artery stenosis greater than or equal to 50% with Doppler sonography when observers use both morphologic and quantitative criteria.

Renal artery stenosis: evaluation of Doppler US after inhibition of angiotensin-converting enzyme with captopril.

PURPOSE: To evaluate the modifications of Doppler ultrasound waveform morphology after inhibition of angiotensin-converting enzyme with captopril to increase the sensitivity of Doppler sonography in detecting renal artery stenosis. MATERIALS AND METHODS: Sixty-two renal arteries were studied in 31 hypertensive patients who underwent Doppler scanning before and 1 hour after administration of captopril prior to undergoing angiography. Pattern recognition criteria were applied to classify the Doppler waveforms as having a normal or pulsus tardus configuration. Doppler scanning results were compared with those of arteriography. RESULTS: On the basis of recognition of the pulsus tardus, precaptopril Doppler scanning showed 13 (68%) of 19 significant renal artery stenoses found at angiography (95% confidence interval, 0.43, 0.85), whereas 19 (100%) of 19 stenoses were detected with postcaptopril Doppler scanning (95% confidence interval, 0.85, 1.0). CONCLUSION: Captopril significantly (95% confidence intervals) increases Doppler scanning sensitivity in detecting renal artery stenoses by inducing or enhancing the pulsus tardus distal to a significant renal artery stenosis.

Renal artery aneurysm: treatment with percutaneous placement of a stent-graft.

A stent-graft was placed percutaneously in the right renal artery of a 50-year-old woman with hypertension and a fibromuscular dysplastic lesion consisting of severe stenoses and a 1.5-cm saccular aneurysm with a wide neck. At 1-year follow-up with arteriography, arterial luminal diameter was normal and no aneurysm was depicted. The patient's blood pressure was normal without blood pressure medication.

T and B cell responses following immunization with tetanus toxoid in IgA nephropathy.

The B and T cell responses were investigated in IgA nephropathy before and after immunization with tetanus toxoid (TT). Both IgA and IgG anti-tetanus toxoid antibodies were elicited, but the IgA antibodies were significantly greater in patients (92.6 +/- 11.7 ELISA units) than in the controls (49.2 +/- 7.5 ELISA units). This was associated with a significantly greater proportion of IgA+ B cells in patients than controls before immunization. However, a significant increase in the proportion of IgA1 binding CD4 and CD8 cells was also found. The proportion of CD3 cells with gamma delta T cell receptors (CD3+TCR gamma delta +), was significantly greater before immunization in the IgA nephropathy patients (37.0% +/- 2.4), compared with controls (10.0% +/- 2.3; P less than 0.001). Immunization with TT further enhanced the CD3+TCR gamma delta + cells in patients to 45.8% +/- 7.2 compared with controls (16.3% +/- 4.5), with a corresponding decrease in CD3+TCR alpha beta + cells in the patients (P less than 0.001). CD3+TCR gamma delta + cells are upregulated by common microbial antigens and clinical exacerbations of IgA nephropathy are frequently associated with mucosal infections and a rise in serum IgA concentration. The increased TCR gamma delta expression may be responsible for the enhanced IgA antibody response in IgA nephropathy. The increase in IgA antibodies may than exert a controlling effect by binding to augmenting T cells and thereby inhibiting their function.

Charge distribution of plasma IgA in IgA nephropathy.

The spectrotype of plasma IgA in patients with IgA nephropathy was studied by isoelectric focussing. Densitometry of the gels showed a significant increase in the anionic region at isoelectric points (pI) 4.7-5.1 (P = 0.02) and a reduction in the cationic region pI 5.8-6.0 (P = 0.03) in patients (n = 15) compared with controls (n = 8). Measurement of the IgA concentration in eluates of sequential slices of the gels showed that the ratio of anionic-to-cationic IgA, using pI 5.6 as the dividing point, was significantly greater in patients (n = 10) than in controls (n = 10) (P = 0.03). Two different methods of analysis have therefore demonstrated an increased proportion of anionic and decreased proportion of cationic IgA in the plasma of patients with IgA nephropathy.

Hypoxemia during hemodialysis: a critical review of the facts.

The literature describing the fall in PaO2 during dialysis is intensively and critically reviewed. This phenomenon is related to both the type of membrane used (cellulosic v noncellulosic membrane), and to the composition of the dialysate (acetate v bicarbonate). It appears that a ventilation/perfusion mismatch due to pulmonary leukostasis can, in part, explain hypoxemia in patients dialyzed with cellulosic membranes. This phenomenon is especially apparent in patients with preexisting pulmonary abnormalities. However, hypoventilation remains the major cause of hypoxemia. This hypoventilation is mainly due to CO2 consumption during acetate metabolism (acetate dialysis), or alkalinization of the blood (bicarbonate dialysis). The metabolic consequences of acetate metabolism, and of bicarbonate and CO2 losses through the dialyzer are critically analyzed. The cause for the increment in oxygen consumption during acetate dialysis is examined. Finally, the respective role of these combined factors are described and used to explain the changes in VCO2, VO2, respiratory quotient (RQ), and PaO2 reported in the literature during dialysis against acetate and/or bicarbonate.

Acetate metabolism during hemodialysis: metabolic considerations.

Acetate is used during regular hemodialysis to replace the bicarbonate lost during dialysis. The temporal changes of plasma bicarbonate and acetate concentrations and the critical role of acetate metabolism for the maintenance of plasma bicarbonate are described. We point out that the maximal rate of acetate oxidation in man is usually reached during dialysis, and we identify physiologic and pathologic factors that may modify this Vmax. A syndrome of 'intolerance to acetate' has been described. This syndrome is analyzed in the light of the metabolic consequences of a rapid flux of acetate oxidation in liver and muscle cells. More specifically, the effects of rapid acetate metabolism on tissue ATP, CoA, adenosine and other ATP degradation products are presented. The possible impact of dialysis-induced depletion of carnitine on optimal acetate metabolism is discussed. The potential clinical consequences produced by these changes are presented in relation to the symptoms sometimes observed during dialysis against acetate: vasodilation, hypotension and angina pectoris. The hypoxemia induced by acetate is also briefly reviewed. Different directions are proposed for future research.