Relationship between obstructive sleep apnea and pulmonary hypertension: past, present and future.

INTRODUCTION: Obstructive sleep apnea (OSA) is a widely prevalent condition with consequent multiple organ systems complications. There is consensus that OSA is associated with negative effects on pulmonary hemodynamics but whether it contributes to development of clinical pulmonary hypertension (PH) is unclear. AREAS COVERED: In this review, we (1) highlight previous studies looking into the possible bidirectional association of OSA and PH, focusing on those that explore clinical prognostic implications, (2) explore potential pathophysiology, (3) discuss the new metrics in OSA, (4) describe endo-phenotyping of OSA, (5) recommend possible risk assessment and screening pathways. EXPERT OPINION: Relying only on symptoms to consider a sleep study in PH patients is a missed opportunity to detect OSA, which, if present and not treated, can worsen outcomes. The potential prognostic role of sleep study metrics such as oxygen desaturation index (ODI), hypoxic burden (HB) and ventilatory burden (VB) in OSA should be studied in prospective trials to identify patients at risk for PH. AHI alone has not provided clarity. In those with PH, we should consider replacing ambulatory overnight pulse oximetry (OPO) with home sleep studies (HST). In PH patients, mild OSA should be sufficient to consider PAP therapy.

Gastrointestinal vaso-occlusive crisis in sickle cell disease.

Although rare, gastrointestinal vaso-occlusive crisis in sickle cell disease results in potentially life-threatening ischemia and death. Here we present a case of a 34-year-old patient with sickle cell disease who developed an acute pain crisis complicated by hypovolemia, hypoxia, and hypotension. The patient was treated with supportive measures. Diagnosis can be challenging and difficult to differentiate from usual pain crisis.

Patient-ventilator dyssynchrony in the intensive care unit: A practical approach to diagnosis and management.

Patient-ventilator dyssynchrony or asynchrony occurs when, for any parameter of respiration, discordance exists between the patient's spontaneous effort and the ventilator's provided support. If not recognised, it may promote oversedation, prolong the duration of mechanical ventilation, create risk for lung injury, and generally confuse the clinical picture. Seven forms of dyssynchrony are common: (a) ineffective triggering; (b) autotriggering; (c) inadequate flow; (d) too much flow; (e) premature cycling; (f) delayed cycling; and (g) peak pressure apnoea. 'Reverse triggering' also occurs and may mimic premature cycling. Correct diagnosis of these phenomena often permits management by simple ventilator optimisation rather than by less desirable measures.

Iatrogenic air embolism.

Air embolism should be treated promptly with high fraction of supplemental oxygen and repositioning to help facilitate reabsorption of the air bubble. Hyperbaric oxygen therapy should be given to those with severe disease.

Renal Function, Weaning, and Survival in Patients With Ventilator-Dependent Respiratory Failure.

BACKGROUND: Acute kidney injury in acute critical illness has been associated with poor weaning and survival outcomes. The relation between renal dysfunction as defined by creatinine clearance (CrCl) and weaning from prolonged mechanical ventilation (PMV) is not known. The objective of this study was to determine the relation of measured CrCl to weaning and survival in patients on PMV. METHODS: We retrospectively studied 167 patients on PMV admitted to a long-term acute care facility for weaning over a 3-year period. Data obtained included age, gender, admission blood urea nitrogen (BUN), serum creatinine, CrCl, random urine creatinine (RUCr), and 24-hour urinary creatinine (24UCr). Renal dysfunction was defined as normal (CrCl > 90 mL/min), mild (CrCl 60-90 mL/min), moderate (CrCl 30-59 mL/min), and severe (CrCl < 30 mL/min). Primary outcome measured was liberation from PMV, defined as being off ventilator for >7 days. Survival, defined as being alive at discharge, time to wean, and time to discharge alive were secondary outcomes. The association between the studied parameters and outcomes was determined by unpaired t test. The predictive value of studied parameters for weaning and survival was determined by multivariate logistic regression analysis. P < .05 was statistically significant. RESULTS: Mean age was 68.5 (14) years; 49% were males; 64% were liberated and 65.8% survived. Blood urea nitrogen, RUCr, 24Ucr, and CrCl had a significant association with successful weaning. These parameters (except BUN) also had a significant association with survival. A better outcome occurred with CrCl > 90 mL/min. CONCLUSION: Measured CrCl has a significant relation to successful weaning and survival in patients on PMV and may be useful in prognosticating their outcome.

Can Creatinine Height Index Predict Weaning and Survival Outcomes in Patients on Prolonged Mechanical Ventilation After Critical Illness?

OBJECTIVE: Malnutrition is common in chronic critically ill patients on prolonged mechanical ventilation (PMV) and may affect weaning. The creatinine height index (CHI), which reflects lean muscle mass, is regarded as the most accurate indicator of malnutrition. The objective of this study was to determine the impact of CHI in comparison with other traditional nutritional indices on successful weaning and survival in patients on PMV after critical illness. METHODS: Records of 167 patients on PMV following critical illness, admitted for weaning, were reviewed. Parameters studied included age, gender, body mass index (BMI), percentage ideal body weight (%IBW), total protein, albumin, prealbumin, hemoglobin (Hb), and cause of respiratory failure. Number successfully weaned and number discharged alive and time to wean and time to discharge alive were determined from records. The CHI was calculated from 24-hour urine creatinine using a standard formula. Unpaired 2-sample t test was performed to determine the association between the studied nutritional parameters and outcomes. Predictive value of studied parameters for successful weaning and survival was determined by multivariate logistic regression analysis to model dichotomous outcome of successful weaning and survival. RESULTS: Mean age was 68 ± 14 years, 49% were males, 64% were successfully weaned, and 65.8% survived. Total protein, Hb, and CHI had a significant impact on successful weaning. Weight, %IBW, BMI, and CHI had a significant effect on survival. Of all parameters, CHI was most strongly predictive of successful weaning and survival. CONCLUSIONS: The CHI is a strong predictor of successful weaning and survival in patients on PMV.

Subcutaneous and Pulmonary Dirofilariasis with Evidence of Splenic Involvement.

Cases of human dirofilariasis have been reported in several countries around the world, including a large number in the Atlantic and Gulf Coast regions of the United States. Most commonly, these cases have subcutaneous or pulmonary involvement; however, there have been few reports of dirofilariasis involving structures such as large vessels, mesentery, the spermatic cord, and liver. We present a case of an unusual presentation of human dirofilariasis presenting as a shoulder abscess and what is presumed to be pulmonary and splenic involvement in a 55-year-old female.

Airbag lung: an unusual case of sarcoid-like granulomatous lung disease after a rollover motor vehicle accident.

Sarcoid-like granulomatous lung disease (SLGLD) is a condition associated with the formation of noncaseating, nonnecrotizing granulomas. The final by-product of airbag deployment is alkaline silicates or glass. Silicates trapped and sequestered in the lung parenchyma are a potential mediator for immune system activation and development of sarcoid-like granulomatous lung disease.

Reactivation of pulmonary tuberculosis following local radiation therapy of prostate cancer.

In this report, we describe the case of an 81-year-old male with reactivation tuberculosis following local radiation therapy for prostate cancer. The patient was asymptomatic except for an unintentional 20-pound weight loss and was incidentally found to have a pulmonary infiltrate in the right upper lobe on imaging for shoulder pain. The medical history was not able for recently treated prostate cancer. After further investigation, the patient was determined to have Mycobacterium tuberculosis infection. It is important to have a high level of suspicion for reactivation tuberculosis in patients with a pulmonary infiltrate following radiation therapy due to the impact of radiation on the host's immune system. We will review the literature on reactivation tuberculosis following radiation therapy and explore the mechanism of immunosuppression in this process. To our knowledge, this is the first reported case of tuberculosis reactivation following local radiation therapy for prostate cancer.

Exercise during cardiac catheterization distinguishes between pulmonary and left ventricular causes of dyspnea in systemic sclerosis patients.

OBJECTIVE: The cause for shortness of breath among systemic sclerosis (SSc) patients is often lacking. We sought to characterize the hemodynamics of these patients by using simple isotonic arm exercise during cardiac catheterization. METHODS: Catheterization was performed in 173 SSc patients when resting echocardiographic pulmonary systolic pressures were <40 but >40 mmHg post stress. Patients with resting mean pulmonary arterial pressures (mPAP) ≤ 25 and pulmonary arterial wedge pressures (PAWP) ≤ 15 mmHg exercised with 1-pound hand weights. Normal exercise was defined as a change in mPAP divided by the change in cardiac output (CO) (ΔmPAP/ΔCO) ratio ≤ 2 for patients <50 years (≤3 for >50). An abnormal ΔmPAP/ΔCO ratio, an exercise transpulmonary gradient (TPG) ≥ 15, a PAWP < 20, a ΔTPG > ΔPAWP and a pulmonary vascular resistance (PVR) which increased defined exercise-induced pulmonary arterial hypertension (EIPAH). An abnormal ΔmPAP/ΔCO ratio, an exercise TPG < 15, a PAWP ≥ 20, a ΔTPG < ΔPAWP and a drop in PVR defined left ventricular diastolic dysfunction (DD). Twelve patients without SSc served as controls. RESULTS: Pulmonary pressures increased with exercise in 53 patients. Six had EIPAH and 47 had DD. With exercise, mPAP and PAWP were 20 ± 4 and 13 ± 2 in controls, 36 ± 3 and 12 ± 4 in EIPAH and 34 ± 6 and 26 ± 4 in DD. Control ΔmPAP/ΔCO was 0.8 ± 0.7, 7.5 ± 3.9 in EIPAH and 9.1 ± 7.2 in DD. Rest and exercise TPG was normal for control and DD patients but increased (12 ± 4 to 23 ± 4) in EIPAH (P < 0.0001). PVR decreased in DD but increased in EIPAH with exercise. CONCLUSIONS: Exercise during catheterization elucidates the pathophysiology of dyspnea and distinguishes EIPAH from the more common DD in SSc patients.

Clinical utility of treprostinil and its overall place in the treatment of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a disease that leads to characteristic vascular wall remodeling and hemodynamic alterations. Consequently, this pulmonary vascular disease contributes to substantial morbidity and mortality in afflicted patients. PAH may be idiopathic in nature or associated with connective tissue disease, chronic liver disease, human immunodeficiency virus, congenital heart disease, and a growing list of other conditions. There are currently nine Food and Drug Administration-approved therapies for specific PAH treatment. Therapeutic targets include prostacyclin replacement, endothelin-1 antagonism, and phosphodiesterase-5 inhibition. This article focuses on the prostanoid treprostinil and explores its role in the management of patients with PAH.

The diagnosis and management of pulmonary embolism.

Pulmonary embolism (PE), most commonly originating from thrombosis in the deep venous system of the lower extremities, remains a controversial area of medicine that frequently generates lively debate. Its clinical presentation varies from asymptomatic, incidentally detected pulmonary emboli to massive embolism resulting in sudden death. Despite the advances made in recent years, a number of fundamental questions remain unanswered regarding the pathogenesis, clinical presentation, diagnosis and treatment of this disease. The diagnosis of PE is confounded by a presentation that may be subtle, atypical, or obscured by a concomitant condition. Safe, minimally invasive techniques have been developed to improve the diagnostic accuracy of the clinical evaluation, and obviate the need to obtain pulmonary arteriography in all but a minority of patients. However, no single diagnostic test is sufficiently sensitive or specific for diagnosis in all patients. This dilemma has resulted in the development of numerous clinical scoring systems to stratify risk, pretest probability and help guide an appropriate diagnostic approach. Anticoagulation therapy with unfractionated heparin (UFH), low molecular weight heparin (LMWH), and Factor Xa inhibitors are the mainstay of therapy for acute PE. The choice of agent is influenced by disease severity, presence or absence of provokingfactors, patient comorbidities, and bleeding risk. These factors also determine whether measures such as thrombectomy, thrombolysis and vena cava filter placement may be employed as adjuncts to anticoagulation. Warfarin is the agent of choice for secondary prevention; newer agents such as direct thrombin and factor Xa inhibitors are emerging as safe and effective alternatives.

"A dropped call".

We present an interesting case of tracheobronchial foreign body aspiration. A 29-year-old healthy female, with no history of pulmonary disease, presented on multiple occasions to healthcare providers with wheezing and cough. She was repeatedly diagnosed and treated for asthma with acute exacerbations. Upon further evaluation, the patient was subsequently found to have a tracheobronchial foreign body causing her symptoms. This case report highlights a clinical approach to wheezing illnesses and reviews the diagnosis and management of tracheobronchial foreign body aspiration.

Survival of geriatric idiopathic pulmonary arterial hypertension patients.

BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) is increasingly being diagnosed in patients of advanced years. We sought to investigate observed vs expected mortality among geriatric IPAH patients treated with specific pulmonary arterial hypertension (PAH) therapy. METHODS: From the University of Connecticut's Pulmonary Vascular Disease Program database, 20 IPAH patients over 65 years of age were identified. Patient demographics, cardiopulmonary hemodynamics, PAH therapy, and mortality were retrospectively analyzed. Based on observed follow-up time, the probability of death was calculated for each subject using a prediction formula for PAH patients developed by the National Institutes of Health (NIH). Byar's method for Poisson counts was used to compare observed and expected tallies of deaths within the study sample. A P value < or = 0.05 was considered statistically significant. RESULTS: The mean age of the 20 geriatric IPAH patients was 77 years (+/- 6.6) of which 70% were female. The mean cardiopulmonary hemodynamic values for the cohort were: right atrial pressure: 10 mmHg (+/- 4); mean pulmonary artery pressure: 45 mmHg (+/- 9); pulmonary artery occlusion pressure: 11 mmHg (+/- 3); cardiac output: 4.1 L/min (+/- 1.2); cardiac index: 2.3 L/min (+/- 0.5); and pulmonary vascular resistance: 712 dynes / sec / cm-5 (+/- 319). Fourteen subjects received PAH monotherapy with bosentan, sildenafil, or epoprostenol. Six subjects received PAH combination therapy with bosentan, sildenafil, iloprost, or treprostinil. Total follow-up across the 20 subjects was 58.7 years, with average follow-up of 2.9 yrs (+/- 1.7) per subject. Based upon the NIH formula, the expected number of deaths for this cohort was 9.4. During follow-up, three deaths actually occurred. Thus, observed mortality was only 31.9% of expected (P = 0.03, 95% C.I. = [6.4%, 93.2%]). CONCLUSION: Geriatric patients are increasingly being diagnosed with IPAH. Efficacy of PAH therapy in geriatric patients is unknown. In this cohort of subjects, the outcomes of older adults treated with specific PAH therapy demonstrates improved survival relative to that predicted by the NIH formula.

An unusual case of septic shock in a geriatric patient.

Capnocytophaga canimorsus is a gram-negative rod that is a normal inhabitant of the oral flora of most dogs, cats and other animals. Clinically significant infections of humans by this common organism are extremely rare. We present a case of an 87-year-old woman who presented with septic shock and multiorgan system failure. Blood cultures were positive for a gram-negative rod that five days after admission was identified as C. canimorsus. She was treated aggressively with intravenous fluid resuscitation, vasopressors and parenteral antibiotics and recovered. The epidemiology, virulence factors, and treatment options for C. canimorsus are discussed.

Successful treatment of sarcoidosis-associated pulmonary hypertension with bosentan.

Sarcoidosis is a systemic granulomatous disease of unknown etiology, in which the lungs and intrathoracic lymph nodes are predominant sites of involvement. Pulmonary hypertension is a known complication of sarcoidosis. Treatment of sarcoidosis-associated pulmonary hypertension has traditionally focused on the initiation of systemic corticosteroids, but has had inconsistent results. We present a patient with sarcoidosis-associated pulmonary hypertension who achieved substantial clinical improvement with the dual endothelin receptor antagonist bosentan.

Reduced exercise capacity and stress-induced pulmonary hypertension in patients with scleroderma.

OBJECTIVES: We sought to determine the incidence of stress-induced pulmonary artery (PA) systolic hypertension in a referral population of patients with scleroderma, and to examine the relation between stress-induced pulmonary systolic hypertension and exercise capacity in this population. BACKGROUND: Early detection of patients with scleroderma at risk for pulmonary hypertension (PHTN) could lead to more timely intervention and thus reduce morbidity and improve mortality. The change in PA systolic pressure (PASP) with exercise provides a possible tool for such detection. METHODS: Sixty-five patients with scleroderma (9 men and 56 women; mean age 51 +/- 12 years [SD]), normal resting PASP, and normal resting left ventricular function underwent exercise Doppler echocardiography using a standard Bruce protocol. Tricuspid regurgitation velocity was measured before and after exercise. Exercise variables including workload achieved in metabolic equivalents (METS), total exercise time, percentage of target heart rate achieved, and PASP at rest and within 60 s after exercise were recorded. RESULTS: Thirty patients (46%) demonstrated an increase in PASP to > 35 mm Hg plus an estimated right atrial pressure of 5 mm Hg. Postexercise PASP inversely correlated to both the maximum workload achieved (r = - 0.34, p = 0.006) and exercise time (r = - 0.31, p = 0.01). In women, the correlation was more significant (r = - 0.38, p = 0.003). Patients in the lowest quartile of exercise time, with the least cardiac workload achieved, produced the highest postexercise PASP. CONCLUSION: Stress-induced PHTN is common in patients with scleroderma, even when resting PASP is normal. Stress Doppler echocardiography identifies scleroderma patients with an abnormal rise in PASP during exertion. Peak PASP is linearly related to exercise time and maximum workload achieved. Measurement of PASP during exercise may prove to be a useful tool for the identification of future resting PHTN.

Cost-effectiveness of community-acquired pneumonia therapy.

Community-acquired pneumonia is a common disease in adults and substantially contributes to morbidity and mortality in the USA and worldwide. Due to the significant costs associated with this disease, there is increasing pressure to evaluate the variation in practices among healthcare providers. The processes of care related to the diagnosis, management and prevention of community-acquired pneumonia are reviewed. Furthermore, the cost-effective strategies for community-acquired pneumonia and the medical evidence that support their usage are outlined.