Effect of acetazolamide on post-NIV metabolic alkalosis in acute exacerbated COPD patients.

OBJECTIVE: Non-invasive ventilation (NIV) is an effective treatment in patients with acute exacerbation of COPD (AECOPD). However, it may induce post-hypercapnic metabolic alkalosis (MA). This study aims to evaluate the effect of acetazolamide (ACET) in AECOPD patients treated with NIV. PATIENTS AND METHODS: Eleven AECOPD patients, with hypercapnic respiratory failure and MA following NIV, were treated with ACET 500 mg for two consecutive days and compared to a matched control group. Patients and controls were non invasively ventilated in a bilevel positive airway pressure (BiPAP) mode to a standard maximal pressure target of 15-20 cmH2O. RESULTS: ACET intra-group analysis showed a significant improvement for PaCO2 (63.9 ± 9.8 vs. 54.9 ± 8.3 mmHg), HCO3- (43.5 ± 5.9 vs. 36.1 ± 5.4 mmol/L) and both arterial pH (7.46 ± 0.06 vs. 7.41 ± 0.06) and urinary pH (6.94 ± 0.77 vs 5.80 ± 0.82), already at day 1. No significant changes in endpoints considered were observed in the control group at any time-point. Inter-group analysis showed significant differences between changes in PaCO2 and HCO3- (delta), both at day 1 and 2. Furthermore, the length of NIV treatment was significantly reduced in the ACET group compared to controls (6 ± 8 vs. 19 ± 19 days). No adverse events were recorded in the ACET and control groups. CONCLUSIONS: ACET appears to be effective and safe in AECOPD patients with post-NIV MA.

Exercise intolerance at high altitude (5050 m): critical power and W'.

The relationship between work rate (WR) and its tolerable duration (t(LIM)) has not been investigated at high altitude (HA). At HA (5050 m) and at sea level (SL), six subjects therefore performed symptom-limited cycle-ergometry: an incremental test (IET) and three constant-WR tests (% of IET WR(max), HA and SL respectively: WR(1) 70±8%, 74±7%; WR(2) 86±14%, 88±10%; WR(3) 105±13%, 104±9%). The power asymptote (CP) and curvature constant (W') of the hyperbolic WR-t(LIM) relationship were reduced at HA compared to SL (CP: 81±21 vs. 123±38 W; W': 7.2±2.9 vs. 13.1±4.3 kJ). HA breathing reserve (estimated maximum voluntary ventilation minus end-exercise ventilation) was also compromised (WR(1): 25±25 vs. 50±18 l min(-1); WR(2): 4±23 vs. 38±23 l min(-1); WR(3): -3±18 vs. 32±24 l min(-1)) with near-maximal dyspnea levels (Borg) (WR(1): 7.2±1.2 vs. 4.8±1.3; WR(2): 8.8±0.8 vs. 5.3±1.2; WR(3): 9.3±1.0 vs. 5.3±1.5). The CP reduction is consistent with a reduced O(2) availability; that of W' with reduced muscle-venous O(2) storage, exacerbated by ventilatory limitation and dyspnea.

Cardiopulmonary exercise testing in the functional and prognostic evaluation of patients with pulmonary diseases.

Exercise testing is increasingly utilized to evaluate the level of exercise intolerance in patients with lung and heart diseases. Cardiopulmonary exercise testing (CPET) is considered the gold standard to study a patient's level of exercise limitation and its causes. The 2 CPET protocols most frequently used in the clinical setting are the maximal incremental and the constant work rate tests. The aim of this review is to focus on the main respiratory diseases for which exercise tolerance is indicated; for example, chronic obstructive pulmonary disease, interstitial lung disease, primary pulmonary hypertension and cystic fibrosis. This review also focuses on the variables/indices that are utilized in the functional and prognostic evaluation. The recognition of abnormal response patterns of ventilatory, cardiac and metabolic limitation to exercise may help in the diagnostic evaluation. In addition, CPET indexes can provide important functional and prognostic information regarding patients with pulmonary disease. Exercise indices, such as peak oxygen uptake (V'O(2 peak)), ventilatory equivalents for carbon dioxide production (V'(E)-/V'CO(2)) and arterial oxygen saturation (S(p)O(2)), have in fact proven to be better predictors of prognosis than lung function measurements obtained at rest. Moreover, useful information on the effects of therapeutic interventions may be obtained by CPET by studying the changes in endurance capacity during high-intensity constant work rate protocols.

Left ventricular diastolic filling in type I diabetes mellitus: a pulsed Doppler echocardiographic study.

OBJECTIVES: Doppler echocardiography was used to assess left ventricular diastolic performance in young patients with type I diabetes mellitus and no clinical signs of heart disease. METHODS: The pattern of transmitral diastolic flow velocity was determined in 82 patients (56 men, 26 women; age 17.7 +/- 7.6) with type I diabetes mellitus and no heart disease. Maximal early diastolic flow velocity (E peak), maximal late diastolic velocity (A peak), the ratio of maximal flow velocity in late diastole to that in early diastole (A/E ratio) and the ratio of the time velocity integral of the diastole (1/3 FF) were measured in all 82 patients and repeated during exercise in 63 of them. Twenty healthy volunteers served as controls. RESULTS: Mean values of the Doppler indexes were not significantly different between the patients and the 20 controls, but diabetic patients with microvascular complications showed patterns of left ventricular diastolic flow velocity which suggested altered diastolic performance, namely lower E peak velocity, higher A peak velocity, raised A/E ratio and reduced 1/3 FF. Among the 63 examined during exercise, different diastolic flow patterns in response to effort made it possible to identify 15 patients with a high rate of autonomic dysfunction, indicating probable impairment of diastolic function and a need for close follow-up. CONCLUSION: Diastolic abnormalities may occur in young diabetic patients without evidence of heart disease and suggest Doppler evaluation is a sensitive method for identifying patients at potential risk of developing clinical heart disease.

Usefulness of left and right oblique subcostal view in the echo-Doppler investigation of pulmonary arterial blood flow in patients with chronic obstructive pulmonary disease. The subxiphoid view in the echo-Doppler evaluation of pulmonary blood flow.

Fifty-nine adult patients with chronic obstructive pulmonary disease (COPD) underwent Doppler and two-dimensional echocardiographic examination to determine the variability of pulmonary arterial blood flow (PABF) from multiple views. Measurement of peak flow velocity (PFV), acceleration time (AT), right ventricular ejection time (RVET), and pulmonary arterial diameter (PAD) was possible in 52 patients (88 percent) by left oblique subcostal view (LOSV), in 38 patients (64.4 percent) by right oblique subcostal view (ROSV), and in only 12 patients (20.3 percent) by short axis parasternal view (SAPV) (p less than 0.05). Overall, PABF was measured in 55 patients (93.2 percent). The LOSV gave consistently higher values of PVF than those obtained either by ROSV (p less than 0.05) or by SAPV (p less than 0.05). We conclude that LOSV and ROSV allow measurement of PABF in the majority of patients with COPD.

Assessment of left ventricular hypertrophy by ECG and VCG in patients with inferior and posterior myocardial infarction. A comparison with echocardiographic data.

Electrocardiographic (ECG) and vectorcardiographic (VCG) QRS voltage criteria have been analyzed in 26 patients with inferior and 17 with posterior myocardial infarction (MI) in comparison with left ventricular (LV) mass and global and regional wall motion as assessed by M-mode and two-dimensional (2D) echocardiography. Transverse plane QRS maximal vector correlated significantly with LV mass in patients with both inferior and posterior MI (r = 0.65 and 0.87, respectively, p less than 0.01). A transverse plane QRS maximal vector greater than 1.5 mV correctly recognized 12 of 15 (80%) and 9 of 12 (75%) patients with respectively inferior and posterior MI and LV mass greater than 221 gm. Of the ECG measurements, S V1-2 + R V5-6 correlated moderately with LV mass in patients with inferior MI (r = 0.47), and R V1-2 + R V5-6 correlated moderately with LV mass in those with posterior MI (r = 0.67). ECG and VCG QRS voltage data did not correlate with global and regional LV function as assessed by M-mode and 2D echocardiography. We conclude that: ECG and VCG QRS voltage parameters can be utilized for assessing non-invasively LV enlargement in patients with postero-inferior MI; ECG and VCG QRS voltage parameters should be utilized with caution for analyzing LV function or MI size in postero-inferior MI.

Assessment of tricuspid regurgitation by pulsed Doppler ultrasonography of the hepatic veins.

Pulsed Doppler echocardiography was tested to assess the degree of tricuspid regurgitation (TR), classified by right ventriculography, in 47 patients. Forty-eight subjects without TR served as controls (39 with sinus rhythm and 9 with atrial fibrillation). Two Doppler methods were used: the distance of systolic turbulence within right atrium from the tricuspid plane and the quantitative analysis of the flow-velocity traces from the hepatic veins (HVs). Right atrial systolic turbulence was found in 41 of 47 patients with TR and in none of the control subjects, and moderately correlated with the angiographic grading (r = 0.57). In control subjects, TR flow-velocity traces from the HVs showed 2 anterograde flow waves, systolic and diastolic. The ratio of anterograde systolic/anterograde diastolic velocity was more than 0.6 in 38 subjects with sinus rhythm and in 8 with atrial fibrillation. Twenty-two control subjects had a positive wave (designated as "v") coincident with the end of T wave. In 30 patients with TR, a retrograde holosystolic wave was present. Of the remaining patients, 12 had a ratio of anterograde systolic/anterograde diastolic velocity less than 0.6. Fifteen had an end-systolic "v-like" wave, which occurred earlier than the v wave in control subjects (p less than 0.001). In patients with TR, maximal velocities of the anterograde diastolic and retrograde systolic flow correlated with angiographic grading (r = 0.74 and 0.73, respectively). An anterograde diastolic flow velocity more than 26 cm/s and a retrograde systolic flow velocity more than 16 cm/s excluded mild TR. Analysis of Doppler recordings of the HVs is valuable to semiquantitatively assess TR, complementing the right atrial Doppler findings.

[Bidimensional echocardiographic findings in a case of arrhythmogenic dysplasia of the right ventricle]. / Rilievi ecocardiografici bidimensionali in un caso di displasia aritmogena del ventricolo destro.

In a 50-year-old man presenting with dyspnoea and palpitations, cardiomegaly, incomplete right bundle branch block and bursts of ventricular tachycardia, Two-Dimensional Echocardiography revealed an impressive enlargement of the right ventricle, particulary in the outflow tract. Arrhythmogenic right ventricular dysplasia was suggested and confirmed by right ventricular angiography and electrophysiologic study. We emphasize the role of Two-Dimensional Echocardiography in the appropriate planning of cardiac catheterization for a definitive diagnosis of arrhythmogenic right ventricular dysplasia.