Pulmonary hypertension in systemic sclerosis and systemic lupus erythematosus.

Pulmonary arterial hypertension (PAH) is a severe manifestation of systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). Due to improvements in the understanding of the pathogenesis of these diseases, improved methodological rigour in the conduct of epidemiological studies and the advent of successful therapies, our understanding of SSc-PAH and SLE-PAH has evolved considerably. In this review we will review the current evidence regarding the prevalence, prognostic factors and survival estimates for SSc-PAH and SLE-PAH. In doing so, we will compare and contrast these two diseases, highlight clinically useful features, discuss methodological limitations of existing data, and draw attention to areas where research is needed.

The pulmonary vascular complications of hereditary haemorrhagic telangiectasia.

Hereditary haemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder, characterised by the presence of vascular malformations. The pulmonary vascular complications of HHT include pulmonary arteriovenous malformations, pulmonary hypertension associated with high-output heart failure and liver vascular malformations and, finally, pulmonary arterial hypertension secondary to HHT. In the present review, the authors describe the clinical presentation, diagnosis and management of all three pulmonary vascular presentations of HHT, as well as the underlying genetics and pathophysiology.

Discordance between microneurographic and heart-rate spectral indices of sympathetic activity in pulmonary arterial hypertension.

OBJECTIVES: To determine, in patients with pulmonary arterial hypertension (PAH), whether there is a relationship: (1) between sympathetic nerve firing rate and spectral indices of sympathetic neural heart rate modulation; and (2) between heart rate variability (HRV) and right atrial pressure, a stimulus to sinoatrial node stretch. DESIGN: Characterisation of patients and healthy controls. SETTING: Teaching hospital-based study. PATIENTS: 9 PAH patients without elevated pulmonary capillary wedge pressure and nine age-matched control subjects. INTERVENTIONS: Heart rate (HR) and muscle sympathetic nerve activity (MSNA) were recorded during 10 min of supine rest in both PAH patients studied after right heart catheterisation, and healthy volunteers. Coarse-graining spectral analysis determined HR spectral power. MAIN OUTCOME MEASURES: (1) Low-frequency (PL) spectral component of HRV; (2) MSNA burst frequency; and in PAH patients: (3) right atrial pressure. RESULTS: MSNA burst frequency was higher in PAH patients (48 (24) and 29 (11) bursts/min, respectively; mean (SD); p = 0.05), whereas total power (p = 0.01), its fractal (p<0.01) and harmonic (p = 0.04) components, and PL (p = 0.01) were all reduced. PL related inversely to both MSNA burst frequency (r = -0.86, p = 0.005) and right atrial systolic pressure (r = -0.77, p = 0.04). CONCLUSIONS: Thus, in PAH (as in patients with left ventricular systolic dysfunction) loss of PL relates inversely to gain in MSNA burst frequency. Diminished sympathetic neural heart rate modulation and increased right atrial stretch may combine to attenuate HRV, an adverse prognostic marker.

Anticoagulation in pulmonary arterial hypertension: a qualitative systematic review.

Thrombotic arteriopathy has been implicated in the pathophysiology of pulmonary arterial hypertension (PAH). However, the role of anticoagulants in the treatment of PAH is uncertain. Through a qualitative systematic review of epidemiological studies, the effectiveness of anticoagulation therapy with warfarin on survival was evaluated in patients with PAH. MEDLINE (1966 to November 2005), EMBASE (1966 to November 2005), bibliographies of included studies and published reviews were searched without language restriction. Epidemiological studies evaluating the effectiveness of warfarin in PAH were included. Studies had to report mortality as an outcome. Seven observational studies evaluating the effectiveness of warfarin comprising 488 patients were identified. Five studies support the effectiveness of anticoagulation therapy, whereas two do not. Data from observational studies suggest that anticoagulation therapy may be an effective intervention in pulmonary arterial hypertension. However, given the methodological limitations and the small number of existing observational studies, a randomised controlled trial is needed in order to definitively address this important clinical issue.

Pulmonary hypertension in systemic lupus.

Pulmonary arterial hypertension (PAH) has devastating consequences in the rheumatic diseases; however, the prevalence in lupus is not well delineated. We searched the University of Toronto lupus database to ascertain the first echocardiogram ordered at their physician's discretion between 1995 and 2002. We reviewed the echocardiogram reports for right ventricular systolic pressure (RVSP), valvular disease, and atrial and ventricular function. The PAH was defined as RVSP > or = 40 mmHg. Patients were divided into three groups: RVSP > or = 40 mmHg, RVSP = 30-39 mmHg and RVSP < 30 mmHg. We analysed potential associations between presence of PAH and lupus including disease activity, organ involvement and anticardiolipin antibodies, both at the time of and any time prior to echocardiography. In total, 129 patients underwent echocardiography. Nine patients' echocardiograms were not obtainable, and three patients were excluded from analysis, as their visit was more than six months from the date of echocardiography. Sixteen patients (14%) had RVSP > or = 40 mmHg, 43 (37%) patients had RVSP of 30-39, and 60 (51%) patients had RVSP < 30 mmHg. There was no statistical difference in disease activity, organ involvement or serology among all three groups. In conclusion, the prevalence of PAH (RVSP > or = 40 mmHg) on first echocardiogram ordered at physician discretion in our cohort was 14%. An RVSP of 30-39 mmHg was found in 37% of patients. Although abnormal, the clinical significance of this finding is unknown. Disease activity, organ involvement and anticardiolipin antibodies were not associated with PAH. Further research is needed to identify the mechanism, response to immunosuppression and impact on quality of life in these patients.

Long-term follow-up of survivors of acute lung injury: lack of effect of a ventilation strategy to prevent barotrauma.

OBJECTIVES: To determine the effect of a ventilation strategy to prevent barotrauma on long-term outcome in survivors of acute lung injury. DESIGN: Prospective blinded cohort analysis. SETTING: Three university-affiliated medical-surgical intensive care units. PATIENTS: A total of 28 survivors of acute lung injury, 1-2 yrs after diagnosis, from a multicenter prospective randomized controlled trial comparing pressure (peak inflation pressure < or =30 cm H2O) and volume (tidal volume < or =8 mL/kg) limited ventilation to a conventional (peak inflation pressure < or =50 cm H2O, tidal volume 10-15 mL/kg) ventilation strategy. MEASUREMENTS AND MAIN RESULTS: Physicians blinded as to treatment group evaluated 20 of 28 survivors (treatment group, 7; control group, 13). Exercise tolerance in the 6-minute walk test was comparable to patients with chronic respiratory disease and equivalent between groups (treatment group, 373+/-171 m vs. control group, 375+/-129 m; p = .84). Pulmonary function testing showed reduced diffusing capacity (treatment group, 64+/-29% predicted vs. control group, 74+/-14% predicted; p = .68) and normal volumes, flows, and blood gases. Two domains of disease-specific Health Related Quality of Life assessed by the Chronic Respiratory Questionnaire were worse for patients in the treatment group compared with the control group (Emotional Function 3.8+/-1.4 vs. 5.1+/-0.08; p = .05, Mastery 4.7+/-1.7 vs. 6.2+/-0.8; p = .03). There were no between-group differences in the scores of the Spitzer Quality of Life Index (a generic Health Related Quality of Life instrument), although they were reduced (7.5+/-1.9) and comparable to patients with chronic disease. CONCLUSIONS: We found that 1-2 yrs after the onset of their illness, survivors of acute lung injury have reductions in quality of life and exercise tolerance which are similar to patients with chronic diseases. We were unable to show that a limited ventilation strategy improves either long-term pulmonary function or quality of life in survivors of acute lung injury.

Assessment of three methods to reduce the influence of mathematical coupling on oxygen consumption and delivery relationships.

STUDY OBJECTIVES: To determine if oxygen consumption/oxygen delivery (VO2/DO2) relationships derived using calorimetry (which are not influenced by shared measurement error) agreed with those obtained using the pulmonary artery (PA) catheter alone. To evaluate three strategies to reduce the influence of shared measurement error to determine if agreement between the two methods could be improved. METHODS: Twenty-seven patients were studied following coronary artery bypass surgery. Calorimetric VO2, six thermodilution cardiac outputs (COs), and arterial and mixed venous oxygen content measurements were made at baseline and were repeated 30 min following dobutamine administrations of 3 microg/kg/min and 5 microg/kg/min. RESULTS: Dobutamine produced a dose-dependent increase in DO2, from 378+/-65 mL/min/m2 to 446+/-78 mL/min/m2 (p<0.01) and in both PA catheter and calorimetric-derived VO2, from 104+/-18 mL/min/Mi2 to 114+/-22 mL/min/m2 (p<0.05) and from 117+/-15 mL/min/m2 to 126+/-19 mL/min/m2 (p<0.01), respectively. Agreement was poor (bias=12%, SD=21%) between the calorimetric and PA catheter methods of determining VO2/DO2 slope. When three CO measurements were used to calculate VO2, and three separate CO measurements were used to calculate DO2, the level of agreement between the two methods improved (bias=2%, SD=15%). Increasing the number of COs resulted in a similar improvement in the level of agreement between the two methods. Weighting the slope to the observed change in DO2 was the best method to improve the level of agreement (bias=2%, SD=6% for three COs). CONCLUSIONS: To reduce the influence of shared measurement error, the best strategy to improve the measurement of VO2/DO2 slope is to maximize the change in DO2 (optimally over 100 mL/min/m2).

The acute effects of nasal positive pressure ventilation in patients with advanced cystic fibrosis.

OBJECTIVE: To evaluate the acute effects of noninvasive positive pressure ventilation (NPPV) in patients with stable chronic respiratory failure secondary to cystic fibrosis. PATIENTS: Eight patients (29+/-5 years of age) with severe airflow limitation (mean FEV1, 24+/-3% predicted) and chronic respiratory failure (PaO2=67+/-15 mm Hg and PaCO2=50+/-4 mm Hg) were evaluated. METHODS: Tidal volume, respiratory rate, minute ventilation, oxygen saturation, and transcutaneous CO2 (TcCO2) measurements were made over a 20-min period before and after the application of NPPV (inspiratory pressure of 10 to 12 cm H2O and expiratory pressure of 4 to 6 cm H2O). RESULTS: NPPV increased saturation from 88+/-2% to 90+/-1% (p<0.05) and decreased TcCO2 from 51+/-3 mm Hg to 50+/-2 mm Hg (p<0.05). Tidal volume increased from 219+/-20 mL to 256+/-37 mL (p=not significant [NS]) and respiratory rate decreased from 24+/-2 to 18+/-1 (p<0.01). Minute ventilation decreased from 5.3+/-0.8 L/min to 4.6+/-0.6 L/min (p=0.08). There was no change in duty cycle (32+/-5% to 34+/-5%, p=NS). In two patients, esophageal pressure measurements were also recorded. There was a decrease in pressure from -21+/-1 cm H2O to -11+/-2 cm H2O and -14+/-1 cm H2O to -7+/-1 cm H2O. CONCLUSIONS: In patients with stable, severe cystic fibrosis, NPPV (1) acutely improves gas exchange, (2) decreases minute ventilation, suggesting either a reduction in CO2 production or an increase in alveolar ventilation, and (3) reduces work of breathing.

Evaluation of a ventilation strategy to prevent barotrauma in patients at high risk for acute respiratory distress syndrome. Pressure- and Volume-Limited Ventilation Strategy Group.

BACKGROUND: A strategy of mechanical ventilation that limits airway pressure and tidal volume while permitting hypercapnia has been recommended for patients with the acute respiratory distress syndrome. The goal is to reduce lung injury due to overdistention. However, the efficacy of this approach has not been established. METHODS: Within 24 hours of intubation, patients at high risk for the acute respiratory distress syndrome were randomly assigned to either pressure- and volume-limited ventilation (limited-ventilation group), with the peak inspiratory pressure maintained at 30 cm of water or less and the tidal volume at 8 ml per kilogram of body weight or less, or to conventional ventilation (control group), with the peak inspiratory pressure allowed to rise as high as 50 cm of water and the tidal volume at 10 to 15 ml per kilogram. All other ventilatory variables were similar in the two groups. RESULTS: A total of 120 patients with similar clinical features underwent randomization (60 in each group). The patients in the limited-ventilation and control groups were exposed to different mean (+/-SD) tidal volumes (7.2+/-0.8 vs. 10.8+/-1.0 ml per kilogram, respectively; P<0.001) and peak inspiratory pressures (23.6+/-5.8 vs. 34.0+/-11.0 cm of water, P<0.001). Mortality was 50 percent in the limited-ventilation group and 47 percent in the control group (relative risk, 1.07; 95 percent confidence interval, 0.72 to 1.57; P=0.72). In the limited-ventilation group, permissive hypercapnia (arterial carbon dioxide tension, >50 mm Hg) was more common (52 percent vs. 28 percent, P=0.009), more marked (54.4+/-18.8 vs. 45.7+/-9.8 mm Hg, P=0.002), and more prolonged (146+/-265 vs. 25+/-22 hours, P=0.017) than in the control group. The incidence of barotrauma, the highest multiple-organ-dysfunction score, and the number of episodes of organ failure were similar in the two groups; however, the numbers of patients who required paralytic agents (23 vs. 13, P=0.05) and dialysis for renal failure (13 vs. 5, P= 0.04) were greater in the limited-ventilation group than in the control group. CONCLUSIONS: In patients at high risk for the acute respiratory distress syndrome, a strategy of mechanical ventilation that limits peak inspiratory pressure and tidal volume does not appear to reduce mortality and may increase morbidity.

Treatment of diffuse tracheomalacia secondary to relapsing polychondritis with continuous positive airway pressure.

Relapsing polychondritis (RP) is a rare disease characterized by recurrent inflammation and destruction of the cartilaginous structures. Tracheobronchial chondritis is a dreaded complication of RP. We wish to report a case of RP of the trachea and bronchi which was treated with nasal continuous positive airway pressure.

Leukocytes and decreased left-ventricular contractility during endotoxemia in rabbits.

We hypothesized that leukocytes contribute to decreased myocardial contractility following endotoxin infusion. To test this hypothesis, we administered endotoxin (1 mg/kg intravenously) to intact, anesthetized rabbits whose arterial blood perfused two isolated hearts at a constant pressure (75 mm Hg). One heart was perfused with blood passed through a leukocyte filter, whereas the other received unfiltered blood. Contractility of both hearts was measured every 30 min for 6 h, using the slope of the end-systolic pressure-volume relationship (Emax) and the maximum rate of change of intraventricular pressure (dP/dt(max)). In the unfiltered hearts at 6 h, Emax decreased to 81 +/- 6% (mean +/- SEM) of baseline (p < 0.05). In the hearts perfused with leukocyte-filtered blood there was no change in Emax. Similarly, dP/dt(max) decreased 74 +/- 9% of baseline in the hearts receiving unfiltered blood (p < 0.05) but did not decrease in the hearts receiving leukocyte-filtered blood. The leukocyte filter significantly reduced the number of neutrophils in perfusing blood (p < 0.01), decreased the number of neutrophils in the heart by 77% (p < 0.01), and decreased myocardial morphometric changes (p < 0.05). A 55 +/- 18% reduction in neutrophil L-selectin expression after endotoxin infusion (p < 0.01) suggests that the neutrophils were significantly activated. We conclude that leukocytes, notably activated neutrophils, may contribute to decreased myocardial contractility during septic shock.

Mechanisms of acute lung injury.

Acute lung injury is the end result of common pathways initiated by a variety of local or systemic insults leading to diffuse damage to the pulmonary parenchyma. Despite the accumulation of abundant information regarding the physiological and cellular basis of lung injury and increasingly sophisticated intensive care, an improvement in prognosis has lagged behind. It has become clear that there is not one mediator responsible for acute lung injury but rather a complex interplay exists between diverse proinflammatory (eg, lipopolysaccharide, complement products, cytokines, chemokines, reactive oxygen species, and eicosanoids) and anti-inflammatory (interleukin-10, interleukin-1-RA, PGI2) mediators. It is essential that we obtain a better understanding of the complexities of the acute inflammatory response if we are to successfully intervene to prevent or ameliorate tissue injury. The purpose of this review is to summarize recent developments that have contributed to our understanding of the basic mechanisms of lung injury. We focus on the persistence of the inflammatory response on a local and systemic level, including local mechanisms acting within the alveolar space regulating synthesis, release, and activation of inflammatory mediators; the balance of proteinases and antiproteinases; the abnormalities of surfactant; and the potential importance of endogenously released anti-inflammatory mediators. It is hoped that the results of these studies will provide insights into the pathogenesis of lung injury and lead to novel therapeutic strategies to prevent or ameliorate lung injury.

CPAP improves inspiratory muscle strength in patients with heart failure and central sleep apnea.

Patients with congestive heart failure (CHF) suffer from respiratory muscle weakness which may contribute to dyspnea. Nasal continuous positive airway pressure (NCPAP) can improve left ventricular ejection fraction (LVEF) and reduce dyspnea in patients with CHF and Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) but its effects on respiratory muscle strength are not known. We therefore studied the effects of NCPAP on maximal inspiratory and expiratory pressures (MIP and MEP, respectively), LVEF, dyspnea, and fatigue in patients with chronic CHF and CSR-CSA over 3 mo. Eight patients were randomized to control and nine to nightly NCPAP. There were no significant changes in any of these factors in the control group during the study. In contrast, among the NCPAP group, MIP increased from 79.3 +/- 8.1 to 90.7 +/- 10.4 cm H2O (mean +/- SEM; p < 0.02), LVEF increased from 24.0 +/- 4.0 to 32.6 +/- 6.6% (p < 0.02) and symptoms of dyspnea and fatigue were alleviated. However, MEP did not change. In addition, the number of apneas and hypopneas decreased from 49 +/- 11 to 17 +/- 7 per hour of sleep (p < 0.001) and mean low Sao2 during sleep increased from 87.9 +/- 1.0 to 93.0 +/- 1.0% (p < 0.01). Our data indicate that nightly application of NCPAP in patients with CHF and CSR-CSA improves inspiratory muscle strength and LVEF, and relieves dyspnea and fatigue.

Community-acquired pneumonia in the elderly patient. Clinical features, epidemiology, and treatment.

The relationship between age and the incidence of and mortality associated with pneumonia is complex. Age itself may not be an independent risk factor, because elderly patients also have a concomitant increase in the number of underlying risk factors for disease. The authors review the clinical features, epidemiology, and treatment of community-acquired pneumonia.

Cavitary aspergillosis as a complication of AIDS.

The authors report the radiographic findings in two patients with the human immunodeficiency virus (HIV) who presented with cavitary lung disease caused by Aspergillus. Recognition of the disease in one of the patients led to successful medical therapy. Disease due to Aspergillus must be considered in HIV-positive patients with cystic or cavitary disease appearing in chest radiographs.