Different normalizations for body size and population attributable risk of left ventricular hypertrophy: the MAVI study.

BACKGROUND: Different methods of normalizing left ventricular (LV) mass for body size identify generally similar relative risks of adverse cardiovascular outcome but with variable prevalences of LV hypertrophy (H). Preliminary results from a population with high prevalence of obesity suggest that the population attributable-risk percent (PAR%) of LVH is substantially higher when LV mass is normalized for allometric power of height. METHODS: We calculated the PAR% of LVH by different definitions in the cohort of the MAssa Ventricolare sinistra nell' Ipertensione (MAVI) study (n = 1019, 62% women), a population with low prevalence of obesity (22%, with only 3% and 0.1% in class II and class III obesity, respectively). Composite fatal and nonfatal cardiovascular events occurred in 53 participants (5.2%). RESULTS: Prevalence of LVH was between 28% and 56%, with slight greater values for height-based normalization. Age- and sex-adjusted hazard ratios were comprised between 1.37 and 1.44 for different measures of LV mass index. The PAR% was not meaningfully different among the different methods of normalization (between 47% and 56%), and height-based methods showed in general a performance similar to body surface area-based normalizations. CONCLUSIONS: In a large clinical population of hypertensive subjects with low prevalence of obesity, population risk attributable to LV hypertrophy was not meaningfully different in relation to the type of normalization of LV mass for body size. Height-based methods perform as well as body surface area-based ones. We suggest that the prevalence of obesity in hypertensive populations might substantially influence differences in population risk attributable to LVH identified by different methods of normalizing LV mass.

Costs of the COPD. Differences between intensive care unit and respiratory intermediate care unit.

INTRODUCTION: To assess whether respiratory intermediate care units (RICUs) are cost effective alternatives to intensive care units (ICUs) for patients with exacerbation of chronic obstructive pulmonary disease (COPD). PATIENTS AND METHODS: Multi-centre, prospective, bottom-up cost study performed in 15 ICUs and 6 RICUs. COPD patients staying longer than 48 h were recruited; those coming from other ICUs/RICUs, with immune-deficiency or stroke, were excluded. After the ICU sample was standardised to the RICU distribution of the reason-for-admission and infusion of a vasoactive drug on admission, 60 ICU patients and 65 RICU patients remained, of the original 164 recruited. For each patient, besides clinical data on admission and discharge, daily information about the resources consumed were recorded and analysed in terms of their costs. RESULTS: Total cost per patient was lower in RICUs than in ICUs (754 vs. 1507 Euro; P < 0.0001). In all items, except drugs and nutrition, we found a significant lower cost in RICUs. Dead patients were noticeably different in terms of disease severity between ICUs and RICUs, while surviving ones were not. CONCLUSIONS: Our study suggests that some COPD patients, less severe and with pure respiratory failure, could be successfully and less costly treated in RICUs.

Non-invasive negative and positive pressure ventilation in the treatment of acute on chronic respiratory failure.

OBJECTIVE: To investigate in clinical practice the role of non-invasive mechanical ventilation in the treatment of acute respiratory failure on chronic respiratory disorders. DESIGN: An 18 months prospective cohort study. SETTING: A specialised respiratory intensive care unit in a university-affiliated hospital. PATIENTS: A total of 258 consecutive patients with acute respiratory failure on chronic respiratory disorders. INTERVENTIONS: Criteria for starting non-invasive mechanical ventilation and for endotracheal intubation were predefined. Non-invasive mechanical ventilation was provided by positive pressure (NPPV) ventilators or iron lung (NPV). RESULTS: The main characteristics of patients (70% with chronic obstructive pulmonary disease) on admission were (mean, SD or median, 25th-75th centiles): pH 7.29 (0.07), PaCO(2) 83 mm Hg (19), PaO(2)/FiO(2) 198 (77), APACHE II score 19 (15-24). Among the 258 patients, 200 (77%) were treated exclusively with non-invasive mechanical ventilation (40% with NPV, 23% with NPPV, and 14% with the sequential use of both), and 35 (14%) with invasive mechanical ventilation. In patients in whom NPV or NPPV failed, the sequential use of the alternative non-invasive ventilatory technique allowed a significant reduction in the failure of non-invasive mechanical ventilation (from 23.4 to 8.8%, p=0.002, and from 25.3 to 5%, p=0.0001, respectively). In patients as a whole, the hospital mortality (21%) was lower than that estimated by APACHE II score (28%). CONCLUSIONS: Using NPV and NPPV it was possible in clinical practice to avoid endotracheal intubation in the large majority of unselected patients with acute respiratory failure on chronic respiratory disorders needing ventilatory support. The sequential use of both modalities may increase further the effectiveness of non-invasive mechanical ventilation.

Prevalence and prognostic role of cardiovascular complications in patients with exacerbation of chronic obstructive pulmonary disease admitted to Italian respiratory intensive care units.

BACKGROUND: Cardiovascular complications are frequently observed in patients with chronic obstructive pulmonary disease (COPD) admitted to respiratory intensive care units and may affect the prognosis. The aims of this study were to evaluate a) the prevalence of cardiovascular complications in patients with COPD exacerbation admitted to respiratory intensive care units, b) which parameters detected at admission were predictive of cardiovascular complications, and c) the prognostic role of cardiovascular complications. METHODS: A series of 278 consecutive patients with COPD admitted to 11 Italian respiratory intensive care units between November 1997 and January 1998 has been retrospectively analyzed. All cardiovascular complications were recorded. RESULTS: One hundred and ten patients (39.6%) developed cardiovascular complications: congestive heart failure 49 (17.6%), arrhythmias 40 (14.4%), shock 13 (4.7%), and hypotension 11 (4%). Multivariate analysis showed that the APACHE II score, ECG abnormalities (supraventricular ectopic beats, right and/or left ventricular hypertrophy) and digoxin therapy were independent predictors of cardiovascular complications. The overall mortality was 9% being 4.7% in patients without and 15.5% in patients with cardiovascular complications (p = 0.0044). Multivariate analysis showed that the APACHE II score, respiratory rate, pneumonia and end-stage respiratory diseases were independent predictors of mortality. CONCLUSIONS: Cardiovascular complications occurred in many patients with COPD exacerbation admitted to respiratory intensive care units, and identify a subset of patients with higher mortality.

Iron lung vs mask ventilation in the treatment of acute on chronic respiratory failure in COPD patients: a multicenter study.

STUDY OBJECTIVES: Evaluation of the effectiveness of negative-pressure ventilation (NPV) with the use of the iron lung vs noninvasive positive-pressure ventilation (NIPPV) in the treatment of COPD patients with acute on chronic respiratory failure. DESIGN: A retrospective case-control study. SETTING: Four Italian respiratory intermediate ICUs. PATIENTS: Of a total of 393 COPD patients admitted to the ICU in 1996, 53 pairs were treated with the iron lung (NPV group). Patients treated with NIPPV (NIPPV group) were matched according to mean (+/- SD) age (70.3 +/- 7.1 vs 70.3 +/- 6.9 years, respectively), sex, causes of acute respiratory failure (ARF), APACHE (acute physiology and chronic health evaluation) II score (22.4 +/- 5.3 vs 22.1 +/- 4.6, respectively), pH (7.26 +/- 0.05 vs 7.27 +/- 0.04, respectively), and PaCO(2) (88.1 +/- 11.5 vs 85.1 +/- 13.5 mm Hg, respectively) on admission to the ICU. The effectiveness of matching was 98.4%. RESULTS: Five patients from the NPV group (9.4%) and seven patients from the NIPPV group (13.2%) needed endotracheal intubation (EI). The treatment failure rate (ie, death and/or need of EI) was 20.7% in the NPV group and 24.5% in the NIPPV group (difference was not significant). The mean duration of mechanical ventilation (29.6 +/- 28.6 vs 62.3 +/- 35.7 h, respectively) and length of hospital stay (10.4 +/- 4.3 vs 15 +/- 5.2 d, respectively) among the 35 concordant surviving pairs were significantly lower in the NPV group than in the NIPPV group (p = 0.001 and p = 0.001, respectively). CONCLUSIONS: These data suggest that both ventilatory techniques are equally effective in avoiding EI and death in COPD patients with ARF. Prospective trials are needed to confirm these preliminary results.

Long-term negative pressure ventilation.

Noninvasive mechanical ventilatory techniques include the use of negative and positive pressure ventilators. Negative pressure ventilators support ventilation by exposing the surface of the chest wall to subatmospheric pressure during inspiration, whereas expiration occurs when the pressure around the chest wall increases and becomes equal to or greater than atmospheric pressure. In this article, a description of negative pressure ventilators and the physiologic effects of negative pressure ventilation (NPV) is given, and the application of this technique in the long-term treatment of chronic respiratory failure is summarized. Many studies, although uncontrolled, have shown that long-term treatment with NPV can improve respiratory muscle function, arterial blood gases, and survival in patients with neuromuscular and chest wall disorders. NPV devices, however, are more cumbersome and difficult to use than home positive pressure ventilators (PPVs) and tend to predispose to obstructive apnoeas during sleep. In the last several decades, NPV has been supplanted by mask PPV. In experienced hands, NPV remains a second viable option in patients with neuromuscular and chest wall disorders who, for technical or other reasons, cannot be offered mask PPV. There is no evidence, however, that long-term treatment with NPV can improve respiratory muscle function, exercise endurance, quality of life, and survival in patients with severe chronic obstructive pulmonary disease.