Preoperative pulmonary function testing for patients with lung cancer.

Preoperative functional assessment of patients who are scheduled to undergo pulmonary resection for carcinoma of the lung can assist the clinician in determining perioperative risk. Physiologic alterations that occur after thoracotomy, including changes in lung volume, ventilatory pattern, gas exchange, and respiratory defense mechanisms, impose an increased risk of complications in patients with moderate to severe respiratory impairment. The use and shortcomings of preoperative spirometry and arterial blood gas analysis as predictors of perioperative complications are reviewed. Quantitative radionuclide scintigraphy, and in some cases exercise testing, can further determine the operative risk of patients with lung cancer. For patients with increased risk, implementation of prophylactic measures may decrease postoperative complications.

Diagnosing ventilator-associated pneumonia: the role of bronchoscopy.

OBJECTIVE: To discuss the two diagnostic procedures used most frequently to obtain uncontaminated lower airway secretions during bronchoscopy. DESIGN: This article reviews the contributing risk factors of ventilator-associated pneumonia (VAP) and the recent studies that have assessed the usefulness of the protected specimen brush (PSB) and bronchoalveolar lavage (BAL) in the nonimmunocompromised host. RESULTS: A prompt, accurate diagnosis of VAP, including specific identification of the bacterial pathogen, remains a common challenge in the intensive-care unit. Standard clinical criteria are of suboptimal specificity for making decisions, including selecting antibiotic therapy. Bronchoscopic techniques of lung secretion sampling can be used in the intensive-care unit in an effort to overcome the effects of oropharyngeal contamination. The PSB and BAL, used appropriately, can help intensive-care clinicians formulate specific antimicrobial therapy. Evaluation of intracellular bacteria obtained by BAL has been reported to be useful in guiding empiric antibiotic therapy while the final results of cultures obtained with the PSB are pending. Prior antibiotic therapy, however, may confound the interpretation and clinical utility of results. CONCLUSION: Currently, for a patient taking antibiotic therapy, no reliable technique nor quantitative culture threshold exists to help in diagnosing suspected VAP or in guiding antibiotic therapy. If the clinical situation allows, antibiotic therapy should be discontinued for 48 hours; then, the PSB, BAL, protected BAL, or endobronchial aspiration should be used. These contemporary modalities, however, necessitate further clinical trials before widespread use is warranted.

Staging systems of lung cancer.

The staging of lung cancer involves assessment of the anatomic extent of disease based on the best available data. Such a definition of neoplastic burden facilitates the systematic analysis and meaningful communication of diagnostic, therapeutic, and prognostic information. Clinical staging involves the best estimate of extent of disease before performance of surgical resection or biopsy procedures (or both). Surgical-pathologic staging is based on the histopathologic analysis of resected specimens, including determining the extent of local and regional disease. During the past 50 years, two major classification schemes for staging of lung cancer have evolved--one for non-small-cell lung cancers (the TNM system, indicating the status of primary tumor [T], regional lymph node [N], and metastatic [M] involvement) and the other for small-cell carcinoma of the lung (based on limited versus extensive disease). In this report, we review the evolution of the current staging systems used for primary lung cancer and their prognostic implications.

Human immunodeficiency virus infection and pulmonary hypertension: two new cases and a review of 86 reported cases.

In this article, we describe pulmonary hypertension in two men (31 and 43 years of age) with human immunodeficiency virus (HIV) infection who were examined at Mayo Clinic Rochester. Among 88 reported cases (including the two current ones) of HIV- or acquired immunodeficiency syndrome (AIDS)-associated pulmonary hypertension, 61% were male; the age range was 2 to 56 years (mean, 32). Dyspnea was the usual initial symptom. Of the 74 patients in whom pulmonary artery pressure was recorded or calculated by echocardiography, systolic pressures ranged from 49 to 118 mm Hg (mean, 68). Of the 33 cases in which lung tissue was evaluated microscopically, 28 (85%) were of the plexogenic variant of pulmonary arterial hypertension. Of the other five cases examined histologically, three consisted of thrombotic pulmonary arteriopathy (one was due to recurrent thromboembolism, and the other two were due to in situ thrombosis), and two were of pulmonary venoocclusive disease. No correlation existed between either CD4 counts or a history of pulmonary infections and the development of pulmonary hypertension. In 15 of the 88 patients (17%), confounding factors for hypertensive pulmonary vascular disease were present, including coexisting liver disease in 13 and coagulation abnormalities in 2. In 83% of the patients, the development of pulmonary hypertension seems to have been related primarily to the chronic HIV infection. Pulmonary hypertension was more rapidly progressive in patients with HIV or AIDS than in those with primary pulmonary hypertension; the reported time intervals between onset of symptoms and diagnosis were 6 months and 30 months, respectively. The 1-year survival rate for patients with HIV and pulmonary hypertension was 51%, based on the follow-up data compiled from the 63 patients in whom it was described; this compares with a 1-year survival rate of 68% for patients with primary pulmonary hypertension. Death was considered a direct consequence of pulmonary hypertension in 29 (76%) of the 38 fatal cases.

Bronchial carcinoid tumors.

Bronchial carcinoid tumors, termed (incorrectly) "bronchial adenomas" in the past, are uncommon pulmonary neoplasms. These tumors are currently classified as neuroendocrine in origin because of their potential to form and sometimes secrete a variety of chemical substances. Overall, approximately 75% of bronchial carcinoid tumors arise in the lobar bronchi, 10% occur in the main-stem bronchi, and 15% originate in the periphery of the lung. Well-differentiated carcinoid tumors constitute almost 90% of all bronchial carcinoids. Atypical carcinoid tumors have a higher malignant potential than do typical bronchial carcinoids. The carcinoid syndrome is rarely, if ever, associated with carcinoids limited to the tracheobronchial tree. Occasionally, Cushing's syndrome due to ectopic hormone production is caused by bronchial carcinoid tumors. More than 75% of bronchial carcinoids are detected on conventional posteroanterior chest roentgenograms. Computed tomography may help disclose small neoplasms that are occult on conventional roentgenography, particularly in the assessment of patients who have Cushing's syndrome due to ectopic hormone production. Pulmonary resection is the treatment of choice for bronchial carcinoids. The prognosis is related to the pathologic grade and stage of the tumor.

The control of breathing during weaning from mechanical ventilation.

Using the recruitment threshold technique, we measured the CO2 responsiveness of the unloaded respiratory pump in 14 mechanically ventilated patients prior to weaning. The CO2 recruitment threshold (CO2RT) was compared with the arterial CO2 tension during unassisted breathing (CO2SB) and with the PaCO2 during mechanical ventilation (CO2MV) at machine settings determined by the primary physician. Based on these comparisons, we tested the hypotheses that (1) patients without weaning-induced respiratory distress (group 1) maintain CO2SB near CO2RT, (2) patients with weaning-induced respiratory distress (group 2) retain CO2SB above CO2RT, thereby manifesting incomplete load compensation, and (3) CO2MV is ventilator setting dependent and provides insufficient information about the ventilatory requirement during weaning. Respiratory distress was prospectively defined as sustained tachypnea (rate greater than or equal to 30) or intense dyspnea (Borg scale rating) and limited weaning in nine of 14 patients. The average CO2RT was 40 mm Hg in both groups. All patients in group 1 maintained CO2SB near CO2RT (p greater than 0.1). Seven of nine patients in group 2 retained CO2 by greater than or equal to 3 mm Hg above CO2RT (p less than 0.01). There was no significant difference between CO2MV and CO2SB in either group. We conclude that CO2RT provides a better reference of the adequacy of ventilatory load compensation during weather than CO2MV.

Dextran 70 embolization. Another cause of pulmonary hemorrhage, coagulopathy, and rhabdomyolysis.

Thirty-two percent dextran 70 is a highly viscous polysaccharide liquid used for uterine distention during hysteroscopy. Although generally safe, this agent has been recognized recently to cause noncardiogenic pulmonary edema, renal insufficiency, and intravascular coagulopathy. We report a case of acute 32 percent dextran 70 embolization, associated with intravascular coagulopathy, bilateral lung infiltrates, and rhabdomyolysis, recognized initially by hemoptysis and pleuritic chest pain while the patient was in the recovery room following a hysteroscopic procedure. Pulmonary, anesthesiology, and critical care physicians should be aware of these potential complications of hysteroscopic surgery.

The assessment of major airway function in a ventilator-dependent patient with tracheomalacia.

A 60-pack-year smoker presented with cough, dyspnea and orthopnea of three months' duration. Spirometry revealed severe reduction in maximal expiratory flow; CT of the chest and bronchoscopy demonstrated expiratory collapse of a mid-tracheal segment, and a presumptive diagnosis of tracheomalacia was made. A right lateral thoracotomy was performed to resect the unstable segment and improve maximal expiratory flow. Diffuse major airway disease with absence of cartilaginous rings from the thoracic inlet to the mainstem bronchi was encountered. The trachea and mainstem bronchi were stented externally. A high resistance to airflow and absence of expiratory flow limitation were present, suggesting a fixed rather than variable intrathoracic obstruction of major airways. This case illustrates some potential pitfalls in preoperative assessment of patients with tracheomalacia. Recordings of airway pressure and flow during mechanical ventilation are useful in distinguishing between fixed and variable intrathoracic obstruction and may complement tests of airway anatomy.

Visualization of diaphragmatic fenestration associated with catamenial pneumothorax.

Catamenial pneumothorax is a rare entity of unknown etiology characterized by recurrent accumulation of air in the thoracic space during or preceding menstruation. We documented the presence of a diaphragmatic fenestration during thoracoscopy, lending support for hypotheses involving diaphragmatic defects as possible avenues of air collection in the thorax.

Oxygen-induced hypercarbia in obstructive pulmonary disease.

We investigated the mechanisms responsible for oxygen-induced hypercarbia in ventilator-dependent patients with advanced chronic obstructive pulmonary disease (COPD). To quantitate the effects of oxygen (O2) on respiratory drive, we determined the CO2 recruitment threshold (PCO2 RT) in 10 mechanically ventilated patients under normoxic (PaO2 = 67 +/- 7 mm Hg) and hyperoxic (PaO2 = 370 +/- 67 mm Hg) conditions. PCO2 RT is a measure of the CO2 responsiveness of the mechanically unloaded respiratory system and, as such, is independent of mechanical impedance and respiratory muscle strength. After O2 supplementation, PCO2 RT increased from 42 +/- 6 to 45 +/- 6 mm Hg (p less than or equal to 0.05), indicating a suppression of so-called hypoxic respiratory drive. The effect of hyperoxia on the dead space to tidal volume ratio (VD/VT) and CO2 elimination (VCO2) was studied in 6 patients. Measurements were made at identical ventilator settings, thus eliminating breathing pattern- and respiratory work-related effects on these variables. VD/VT rose from 0.49 +/- 0.09 to 0.55 +/- 0.06 (p less than or equal to 0.05), but VCO2 remained constant at 0.21 L/min. We discuss why measuring O2-induced changes in minute ventilation, VCO2, PaO2, and VD/VT in spontaneously breathing patients is insufficient to distinguish between gas exchange- and respiratory drive-related mechanisms for hypercarbia. Based on the O2-induced increase in PCO2 RT, we conclude that so-called suppression of hypoxic drive plays an important role in the pathogenesis of this disorder.

Hyponatremia and hypoglycemia in acute Sheehan's syndrome.

We report the case of a 23-year-old Saudi Arabian woman who presented to the medical intensive care unit with severe hyponatremia and hypoglycemia following a Cesarean section delivery complicated by hemorrhage due to disseminated intravascular coagulopathy. She was treated successfully for adrenal insufficiency acutely, and was later discharged on hormone replacement therapy. To our knowledge, this is the first case report of acute Sheehan's syndrome presenting with both hyponatremia and suggestive hypoglycemia. Pituitary necrosis is an uncommon complication of peripartum hemorrhagic shock. Since the initial description by Sheehan in 1937, the incidence of the syndrome has gradually declined through improved management of hemodynamic complications leading to the infarction of the gland. There are many studies describing complications of late Sheehan's syndrome; however, relatively few contain descriptions of the acute phase. In addition, the diagnosis of this syndrome is often determined after resolution of the acute process with resultant lack of data regarding immediate endocrine and imaging abnormalities. In this report, we describe the complete endocrine and imaging assessment of a patient presenting in critical condition due to necrosis of the pituitary gland in the immediate postpartum period.

Anaphylaxis induced by the carboxymethylcellulose component of injectable triamcinolone acetonide suspension (Kenalog).

BACKGROUND: Allergic reactions to various corticosteroids are rare but have been reported previously. OBJECTIVE: We wished to determine the etiology of an anaphylactic reaction in a patient who had received intracutaneous Kenalog (triamcinolone acetonide). METHODS: Skin testing and serologic testing for allergen-specific IgE antibodies was performed for triamcinolone acetonide, its individual components, and three other corticosteroid preparations in both the patient and six other nonallergic persons. RESULTS: The patient had positive skin tests to only the carboxymethylcellulose component of triamcinolone acetonide. He had negative skin test reactions to three other steroid preparations which did not contain carboxymethylcellulose. Specific IgE antibodies to carboxymethylcellulose were also elevated by immunoassay and immunoblotting. Control patients had negative skin tests to triamcinolone acetonide, its components, and three other corticosteroid preparations, and their sera lacked significant specific IgE antibodies to these materials. CONCLUSIONS: Our results indicate that the triamcinolone acetonide component responsible for the patient's reaction was the suspending agent carboxymethylcellulose. We urge physicians to consider component testing when patients experience allergic-type reactions to drugs.

Acute liver failure: results of a 5-year clinical protocol.

This investigation summarizes and evaluates the results of a clinical protocol that we designed to care for patients with acute liver failure (ALF). Adult patients with ALF were enrolled in the protocol. Grade II portal-systemic encephalopathy prompted admission to the intensive care unit (ICU). Patients who met the clinical criterion were activated for liver transplantation. Intracranial pressure (ICP) was monitored in patients with grade III encephalopathy. An increase in ICP was treated with hyperventilation, diuretics, barbiturates, or a combination thereof. Survival was considered to have occurred if the patient left the hospital alive. Our series included 25 patients. Orthotopic liver transplantation (OLT) was performed on 19 patients, 12 of whom survived. Only 2 of 6 patients who did not undergo transplantation survived. Ten of 11 patients who underwent transplantation before reaching grade IV encephalopathy survived. Only 2 of 8 patients who underwent transplantation after reaching grade IV survived (P = .006). The causes of death included cerebral edema (3 patients), disseminated aspergillosis (3 patients), and other (5 patients). ICP was monitored in 11 patients. Increased pressure was documented by seven of the monitors placed. There was one focal hemorrhage secondary to a subdural monitor. Outcome is improved if transplantation occurs before grade IV encephalopathy. ICP monitoring can be accomplished without significant risk of hemorrhage. In our series, infection with aspergillus occurred frequently and with fatal outcome.