less 7.20, and, possibly, loculated collections of fluid are indications for chest tube drainage.
In patients with bronchiectasis, infection and hemoptysis usually respond to antibiotics.
Neck circumference of 17 in or greater is a clinical finding that has a significant association with obstructive sleep apnea.
Although obstructive sleep apnea may be suspected on the basis of signs and symptoms, it can only be proven with polysomnography.
The first issue to address in a pregnant patient with hypotension is the mechanical effect of the pregnant uterus on venous return; turning the patient to the left lateral decubitus position relieves the compressive effect of the uterus on the inferior vena cava and may restore hemodynamic stability.
Behavioral modification provides potent therapeutic enhancement of most smoking cessation agents and, particularly, nicotine replacement.
Bupropion plus nicotine replacement is more effective for smoking cessation than nicotine replacement alone.
Bupropion is contraindicated in any patient with a history of seizure.
Unless there is evidence that a patient was not mentally competent when executing a living will, had a change of mind, or named another health care proxy to make medical decisions for him or her, a designee has the right to make medical decisions on behalf of a patient, including termination of ventilatory support.
With acute respiratory distress syndrome, mortality was significantly improved by ventilating patients with tidal volumes of 6 mL/kg of ideal body weight and keeping plateau ventilatory pressure at ≤30 cm H2O.
If changes in respirator settings required to prevent hypercapnia have associated untoward effects, it is reasonable to allow arterial PCO2 to rise and, if necessary, prevent acidemia by administration of buffer.
Broad-spectrum systemic antibiotics that penetrate the pancreas are effective in reducing the occurrence of sepsis and improve survival in patients with severe necrotizing pancreatitis.
The restless legs syndrome occurs in older persons, often has a familial occurrence, and must be included in the differential diagnosis of insomnia.
Most cases of restless legs syndrome are idiopathic, although it can occasionally result from coexisting illness such as iron deficiency, uremia, or diabetic polyneuropathy.
Gabapentin is a useful therapy for restless legs syndrome.
Normally there is no appreciable difference (100/min) is not present.
When pulmonary vascular resistance is increased for any reason, pressures do not equilibrate throughout the pulmonary circulation at end-diastole, and the pulmonary artery diastolic pressure is significantly higher than the wedge pressure.
When instituting mechanical ventilation in a patient with chronic hypercapnia, it is critical to avoid the development of respiratory alkalemia secondary to overventilation, and ventilator settings should have pH as a target, rather than PaCO2.
In patients with cor pulmonale caused by chronic hypoxemia, oxygen therapy is the treatment of choice; it may alleviate the heart failure and polycythemia seen in this condition.
The use of neuromuscular blocking agents to facilitate mechanical ventilation can result in persistent neuromuscular blockade due to delayed drug clearance or in an acute myopathy and can be manifested as a failure to wean from the ventilator.
Patients who are mechanically ventilated in the supine position have an approximately sixfold increased risk of developing pneumonia compared with patients maintained in a semirecumbent position.
Elevation of the patient's head to 45 degrees may reduce aspiration and nosocomial pneumonia.
The primary oxygenation criterion for prescribing long-term oxygen therapy is a PaO2 ≤55 mm Hg or SaO2 ≤88%.
A second set of oxygenation criteria includes PaO2 of 56 to 59 mm Hg or SaO2 of 89% with evidence of cor pulmonale.
Oxygen should be prescribed at rest, with exercise, and during sleep to increase PaO2 to ≥60 mm Hg or SaO2 ≥90%.
The benefits of long-term oxygen therapy in patients with severe chronic obstructive pulmonary disease and hypoxemia include reversal of secondary erythrocytosis, improvement in heart failure due to cor pulmonale, enhanced neuropsychologic function, improved exercise capacity, and enhanced survival.
After prolonged acute respiratory failure, successful weaning depends on resolution or control of metabolic, electrolyte, and acid-base abnormalities, cardiac function, and nutritional status.
The presence of systemic hypotension associated with pulmonary emboli indicates a limited pulmonary vascular reserve due to a large volume of clot, and thrombolytic therapy is warranted.
In patients with hemodynamic instability associated with pulmonary emboli, fibrinolytic and heparin therapy does not reduce mortality rate but decreases the need for aggressive therapy such as pressors.
Nasal continuous positive-airway pressure is the standard initial treatment for patients with symptomatic moderate-to-severe obstructive sleep apnea syndrome.
In patients with a pulmonary nodule suspicious for malignancy, obtaining tissue from suspicious lymph nodes is critical for staging and optimal therapy.
Severe chronic obstructive pulmonary disease in young persons is suggestive of α1-antitrypsin deficiency, and an α1-antitrypsin level should be measured.
The likelihood of a solitary pulmonary nodule being malignant substantially decreases if the lesion is small (approximately 1 cm), has smooth borders, is located in a lower lobe, and, most importantly, has central calcification.
Although many factors may account for hypotension in the immediate postintubation period, persistence of hypotension in a patient with severe airway obstruction and rapid respiration suggests the development of auto-positive end-expiratory pressure (auto-PEEP).
The two most common forms of lung involvement in systemic sclerosis are interstitial lung disease and pulmonary vascular disease leading to pulmonary hypertension.
Several pleural diseases are associated with asbestos exposure including: benign pleural effusions; diffuse pleural thickening (asymptomatic); pleural plaques (asymptomatic); and malignant mesothelioma.
Presenting symptoms of malignant mesothelioma include chest pain, dyspnea, cough, and weight loss.
Thoracoscopy is the procedure of choice in a patient with suspected mesothelioma.
In patients with a high pretest probability of pulmonary embolism and high-probability ventilation-perfusion scanning, additional diagnostic testing is not necessary before initiating therapy.
Transfusion-related acute lung injury is the acute onset of respiratory compromise requiring medical intervention within 4 hours of transfused blood products and in the absence of a known cardiopulmonary cause.
Patients with advanced cystic fibrosis undergoing lung transplantation have a survival advantage.
Patients with chronic obstructive pulmonary disease live longer by retaining their own diseased lungs rather than incurring the risks attendant on lung transplantation.
Patients with pulmonary fibrosis have a better life expectancy with lung transplantation.
In patients with suspected primary pulmonary hypertension, secondary causes such as chronic thromboembolic disease must be excluded before beginning treatment.
The successful management of sepsis and the systemic inflammatory response syndrome requires specific therapy directed at the underlying cause and insertion of a central venous catheter to facilitate aggressive goal-directed therapy.
Goal-directed therapy in sepsis includes maintaining the central venous oxygen saturation of 70%; central venous pressure of 8 to 10 mm Hg; and hematocrit ≥30%.
The standard approach to a critically ill patient with an altered mental status includes physical examination, cranial computed tomography, and the discontinuation of all nonessential medications; if these measures are unrevealing, the next step should be bedside electroencephalography (EEG).
As many as 8% of critically ill patients with coma meet the criteria for nonconvulsive status epilepticus (EEG evidence of epileptiform activity, altered level of consciousness [usually coma], and absent tonic-clonic seizure activity).
An unwitnessed cardiac arrest with pulseless ventricular tachycardia/ventricular fibrillation is treated initially with three defibrillatory shocks.
If the nonperfusing arrhythmia persists, the next option is epinephrine, 1 mg intravenously every 3 to 5 minutes, or a single dose of vasopressin, 40 IU as an intravenous bolus.
Patients with preexisting adrenal insufficiency who develop sepsis or another critical illness have a higher-than-average mortality rate unless they receive physiologic replacement doses of hydrocortisone and fludrocortisone.
Up to one half of patients with sepsis but without known adrenal dysfunction have a blunted response to ACTH administration and an increased morbidity risk; these patients also benefit from adrenocorticotropic hormone replacement.
The sequence of venous catheter removal immediately followed by respiratory distress is characteristic of venous air embolism.
In patients with moderate-to-severe asthma not responding to adequate doses of a short-acting β-agonist and inhaled corticosteroids, the next step is addition of a long-acting β-agonist.
For patients with exercise-induced asthma, an inhaled β-agonist should be prescribed before exercise.
Severe community-acquired pneumonia with pancytopenia in the setting of bird exposures requires empiric therapy for the usual causes and psittacosis with the combination of a third-generation cephalosporin plus a macrolide.
Doxycycline and all other tetracyclines are contraindicated during pregnancy, and fluoroquinolones are not approved for use in pregnancy.
Blocking the cholinergic system with ipratropium bromide is an effective and reliable method for treating bronchoconstriction due to β-blockade.
The indicated test for suspected vocal cord dysfunction (VCD) is direct laryngoscopy during an asthma attack, which will reveal partial or complete closure of the glottis during inspiration and is associated with wheezing that is most prominent during inspiration.
Patients who present with refractory asthma and with very rapid onset and equally rapid relief of shortness of breath should be evaluated for VCD.
Patients with chronic eosinophilic pneumonia are typically female and present with fever, sweats, weight loss, cough, dyspnea, and wheezing that have lasted for more than a month.
In patients with chronic eosinophilic syndrome, progressive dense infiltrates that do not conform to lobar or segmental anatomy are characteristically seen in the lung periphery and subpleurally on chest radiography; early treatment with prednisone is recommended.
Cough-variant asthma is nonproductive, provoked by exercise and cold air, disturbs sleep, and worsens after a lower respiratory tract infection.
The inhalation of methacholine produces airway obstruction in most patients with asthma; less than 10% of normal persons have positive responses.
For all patients whose asthma is not controlled with use of a β-agonist, anti-inflammatory therapy with an inhaled corticosteroid or cromolyn sodium should be added and used on a regular basis.
Patients with cystic fibrosis and a bronchitic exacerbation of chronic bronchiectasis with Pseudomonas aeruginosa require intravenous antibiotics with two antipseudomonal agents for 2 to 3 weeks.
Mechanical ventilation is indicated for patients failing initial therapy for exacerbation of asthma or status asthmaticus, as determined by altered mental status, worsening tachypnea, and progressive hypercapnia.
In intubated patients with status asthmaticus, ventilatory settings should include a long expiratory phase, low rate, and low tidal volume to minimize air trapping, even at the expense of an elevated PCO2.
Churg-Strauss syndrome is a systemic vasculitis characterized by eosinophilic infiltration of tissue and vascular and extravascular granulomas; it is preceded by allergic rhinitis and chronic asthma and followed by tissue eosinophilia and systemic vasculitis.
Pulmonary involvement in Churg-Strauss syndrome is the most common manifestation of the disease, being present in virtually all cases, with transient patchy infiltrates, nodular opacities that occasionally cavitate, and, in 25% of cases, pleural effusions (eosinophilic).
Gastroesophageal reflux disease (GERD), alone or in combination with postnasal drip, is the most common cause of chronic cough after postnasal drip.
More than one half of patients with cough caused by GERD have no perception of GERD symptoms.
An empiric trial of a proton pump inhibitor is the most efficient, efficacious, and economical management strategy in the diagnosis of cough secondary to GERD.
In Lemierre syndrome, a young previously healthy person develops a sore throat followed by fever and neck swelling due to internal jugular vein thrombophlebitis; the causative organism is an anaerobic gram-negative rod, Fusobacterium necrophorum.
Cough and wheezing associated with eosinophilia in peripheral blood and sputum are most compatible with bronchial asthma.
Farmer's lung is associated with a restrictive rather than an obstructive functional abnormality, except in late stages of the disease.
In common variable immunodeficiency, the typical presentation includes a history of recurrent respiratory bacterial infections with encapsulated organisms, infectious and noninfectious gastrointestinal disease, and lymphoproliferative disorders.
In patients with suspected common variable immunodeficiency, low levels of immunoglobulins are not sufficient to make the diagnosis; an inability to produce specific antibody to an antigen challenge is confirmatory.
The causes of bronchiectasis in the adult include cystic fibrosis, ciliary dyskinesia, rheumatoid arthritis and other rheumatologic disorders, α1-antitrypsin deficiency, and immunoglobulin deficiency states.
A sweat chloride test is the test of choice to diagnose cystic fibrosis, although it has a false-negative rate of 10%.
With evidence of substantial residual clot in the leg veins, placement of a vena cava filter is warranted to prevent additional embolization in patients who are not candidates for thrombolytic therapy or anticoagulation.
Human granulocytic ehrlichiosis, indicated by the presence of characteristic intracytoplasmic inclusions (“morulae”) in his neutrophils, is confirmed by polymerase chain reaction.
Symptoms of diffuse alveolar hemorrhage (DAH) include dyspnea, dry cough, fever, and mucositis; gross hemoptysis is rare, occurring in less than 15% of patients with DAH after bone marrow transplantation.
DAH occurs in approximately 5% of patients with either autologous or allogeneic bone marrow transplantation; it is seen within 30 days after transplantation as leukocyte counts begin to recover.
The diagnosis of DAH is based on an increasingly bloody fluid return with sequential bronchoalveolar lavage samples, the presence of ≥20% hemosiderin-laden macrophages, or both, and elimination of alternative diagnoses.
Patients with acute respiratory distress syndrome have improved survival when managed with a low tidal volume (6 mL/kg of predicted weight).
Prophylactic antibiotics are not beneficial in the treatment of chemical aspiration, and systemic corticosteroids are not beneficial for the management of acute aspiration pneumonitis.
In persons who quit smoking, lung function improves during the first year by an average of 2%, and the rate of decline in lung function is 31 mL/y, compared with continuing smokers whose lung function declines at 63 mL/y.
The differential diagnosis of interstitial lung disease is lengthy. Clinical evaluation should include the search for “treatable” conditions, such as nonspecific interstitial pneumonia, hypersensitivity pneumonitis, eosinophilic pneumonia, and bronchiolitis obliterans organizing pneumonia.
Silo filler's disease results from inhalation of nitrogen dioxide and other oxides of nitrogen in storage silos and causes a chemical bronchiolitis and alveolitis.
Farmer’s lung is a hypersensitivity pneumonitis that results from exposure to thermophilic Actinomycetes and fungi in moldy hay.
Allergic bronchopulmonary aspergillosis is characterized by severe asthma symptoms, eosinophilia, positive IgG and IgE antibodies to Aspergillus, and mucoid impactions with a characteristic radiographic appearance that can be expectorated as "brown plugs."
In a patient who has severe carbon monoxide toxicity, the most effective initial management for airway protection and for delivery of a high oxygen concentration is endotracheal intubation.
Hyperbaric oxygen is the treatment of choice for severe carbon monoxide toxicity with coma and loss of consciousness.
An anion gap acidosis exists only if the anion gap is elevated beyond normal, usually greater than 14 to 16.
Appropriate respiratory compensation for metabolic acidosis is: 1) the PCO2 is equal to the last two digits of the pH, and 2) the predicted PCO2 is equal to the formula 1.5 × [serum bicarbonate] + 8.
Decompression illness in scuba divers is caused by the accumulation of nitrogen dissolved in tissues under pressure; oxygen therapy accelerates clearance of nitrogen, which is present in the blood and tissues in supersaturated solution.
The major factors for decompression illness are the length and depth of submersion and the rapidity of ascent from depth.
Wegener’s granulomatosis is a small to medium vessel vasculitis with typical involvement of the upper airway, the lungs, the kidneys, and the skin.
Antineutrophil cytoplasmic antibodies (ANCA) are present in greater than 80% of cases of Wegener’s granulomatosis.
Therapy for sarcoidosis is mandatory only when there is evidence of vital organ involvement or when the patient has severe systemic symptoms.
In patients requiring treatment for sarcoidosis, corticosteroids remain the drugs of choice.
The differential diagnosis of interstitial lung disease should include the search for “treatable” conditions, such as nonspecific interstitial pneumonia, hypersensitivity pneumonitis, eosinophilic pneumonia, and bronchiolitis obliterans organizing pneumonia.
Simple silicosis, with small nodules in the lungs shown on radiography, is not associated with symptoms or physiologic abnormalities.
In patients with advanced silicosis, disabling dyspnea occurs secondary to massive fibrosis of the lungs after continued exposure to silica dust.
Patients with chronic berylliosis have shortness of breath, a nonproductive cough, a restrictive pattern on pulmonary function testing, and nodular opacities and hilar adenopathy on chest radiography.
In patients with chronic berylliosis, transbronchial biopsy shows characteristic noncaseating granulomas.
An increased residual volume/total lung capacity (RV/TLC) ratio is commonly seen in obstructive disorders, but may also be due to a neuromuscular restrictive disorder; in such cases a normal forced expiratory volume in 1 sec/forced vital capacity (FEV1/FVC) ratio and the low maximum respiratory pressures indicate neuromuscular weakness.
Hypercapnic respiratory failure is unusual in idiopathic pulmonary fibrosis or chronic thromboembolic pulmonary hypertension.
Acute interstitial pneumonia, synonymous with Hamman-Rich syndrome, is a flu-like illness with delayed onset of shortness of breath; chest radiography shows bilateral infiltrates, and biopsy shows diffuse alveolar damage with hyaline membrane formation.
Bronchiolitis obliterans organizing pneumonia (BOOP) commonly presents as an acute or subacute flu-like illness with dyspnea and cough with crackles, patchy infiltrates on chest radiography, and restrictive physiology with low diffusing lung capacity for carbon monoxide (DLCO).
Histologic confirmation of the diagnosis of BOOP is important because prolonged therapy with corticosteroids is usually beneficial.
The histology of BOOP requires clinical correlation because it is not diagnostic of a specific entity but may represent a tissue response to a variety of lung insults.
Patients with the most severely affected emphysema have increased risk of death from lung-volume-reduction surgery.
Patients with predominantly upper-lobe emphysema and low postrehabilitation exercise capacity have improved survival after lung-volume-reduction surgery.
Initial treatment with a benzodiazepine decreases anxiety and usually decreases heart rate and blood pressure, avoiding the need for specific antihypertensive medication.
Routine use of β-blockers may be detrimental and can unmask the α-adrenergic stimulatory effect of cocaine and worsen hypertension.
Asbestosis is defined as pulmonary fibrosis associated with heavy asbestos exposure.
Asbestos-related pleural plaques are localized thickenings of the parietal pleura, which usually develop on the posterolateral chest wall and may be calcified in up to 50% of persons.
Asbestos-related pleural effusion, diffuse pleural thickening, and rounded atelectasis are other asbestos-associated conditions that are distinct from asbestosis.
Noninvasive ventilatory support is beneficial for many patients with musculoskeletal causes of hypercapnic respiratory failure.
Hypoventilation, most prominent during rapid eye movement sleep, is the hallmark of respiratory neuromuscular weakness as it affects sleep.
With neuromuscular diseases that affect the respiratory muscles, hypoventilation almost always develops during sleep before wakefulness.
Bronchiolitis obliterans, an obstructive disorder, occurs in patients with connective tissue diseases, especially with rheumatoid arthritis.
Pulmonary lymphangioleiomyomatosis (LAM) almost exclusively affects women of childbearing age and most commonly presents with dyspnea and pneumothorax.
The treatment of choice for LAM is hormonal therapy with progesterone; lung transplantation is an option for those with advanced lung disease.
