Technical aspects of endobronchial ultrasound-guided transbronchial needle aspiration: CHEST guideline and expert panel report

BACKGROUND: Endobronchial ultrasound (EBUS) was introduced in the last decade, enabling real-time guidance of transbronchial needle aspiration (TBNA) of mediastinal and hilar structures and parabronchial lung masses. The many publications produced about EBUS-TBNA have led to a better understanding of the performance characteristics of this procedure. The goal of this document was to examine the current literature on the technical aspects of EBUS-TBNA as they relate to patient, technology, and proceduralist factors to provide evidence-based and expert guidance to clinicians. METHODS: Rigorous methodology has been applied to provide a trustworthy evidence-based guideline and expert panel report. A group of approved panelists developed key clinical questions by using the PICO (population, intervention, comparator, and outcome) format that addressed specific topics on the technical aspects of EBUS-TBNA. MEDLINE (via PubMed) and the Cochrane Library were systematically searched for relevant literature, which was supplemented by manual searches. References were screened for inclusion, and well-recognized document evaluation tools were used to assess the quality of included studies, to extract meaningful data, and to grade the level of evidence to support each recommendation or suggestion. RESULTS: Our systematic review and critical analysis of the literature on 15 PICO questions related to the technical aspects of EBUS-TBNA resulted in 12 tatements: 7 evidence-based graded recommendations and 5 ungraded consensus-based statements. Three questions did not have sufficient evidence to generate a statement. CONCLUSIONS: Evidence on the technical aspects of EBUS-TBNA varies in strength but is satisfactory in certain areas to guide clinicians on the best conditions to perform EBUS-guided tissue sampling. Additional research is needed to enhance our knowledge regarding the optimal performance of this effective procedure.(AU)

The diagnosis of ventilator-associated pneumonia: a comparison of histologic, microbiologic, and clinical criteria.

STUDY OBJECTIVE: To evaluate histologic, microbiological, and clinical criteria in the recognition of ventilator-associated pneumonia (VAP) in patients who died while mechanically ventilated. METHODS: The study group consisted of 39 patients who died after a mean of 14 days of mechanical ventilation. Postmortem fiberoptic bronchoscopy (FOB) and open lung biopsy were performed with collection of specimens initiated <1 h after death. The microbiological specimens included suction catheter aspirate of tracheal secretions, FOB-guided protected specimen brush (PSB) of tracheal secretions, blindly placed PSB in a distal airway, FOB-guided PSB in a distal airway, and FOB-guided BAL fluid (BALF) in a distal airway. Qualitative bacteriologic study was performed on all specimens, and quantitative bacteriologic study was performed on all but the suction catheter aspirate of the trachea. A biopsy specimen of peripheral lung parenchyma from the same region sampled by FOB was sent for quantitative culture and histologic analysis. The BALF was analyzed for cell population and percent of neutrophils containing intracellular organisms. The clinical criteria selected for comparison with histologic and microbiological results included a temperature > or =38.5 degrees C during the 48 h prior to death, a WBC count > or =15,000/mm3 in the 48 h prior to death, presence of a bacterial or fungal pathogen on the last sputum culture, radiographic worsening in the week prior to death, and worsening gas exchange defined as a 15% decrease in the PaO2/fraction of inspired oxygen ratio in the 72 h prior to death. RESULTS: None of the quantitative cultures had a reliable positive predictive value for histologic pneumonia. None of the five clinical criteria tested showed agreement with the presence or absence of histologic pneumonia. There was a significant correlation between qualitative and quantitative microbiological results from the distal airway/FOB-guided PSB, distal airway/BALF, and quantitative culture of the lung parenchyma. Also, suction catheter aspirate of the trachea had a sensitivity of 87% in recognizing the bacterial species simultaneously present in lung parenchyma. None of the patients with histologic pneumonia had <50% neutrophils in the BALF. CONCLUSIONS: Neither the bacterial, density from the four airway quantitative cultures, nor the bacterial density from quantitative culture of lung parenchyma accurately separated the histologic pneumonia and nonpneumonia groups. No clinical criteria or combination of clinical criteria correlated with the presence or absence of histologic pneumonia. A BALF with <50% neutrophils had a 100% negative predictive value for histologic pneumonia. A BALF quantitative culture had a sensitivity of 63%, specificity of 96%, and positive predictive value of 91% in recognizing sterile lung parenchyma. Thus, BALF may have a role in excluding pneumonia/infection in the ventilated patient. Antibiotic choice for the empiric therapy of VAP can be accurately guided by the microbial population recognized through culture of a tracheal suction catheter aspirate.

Neoplastic mimics of pneumonia.

Several types of neoplastic conditions are included in the differential diagnosis of pneumonia. Bronchial obstruction with cancer can produce obstructive pneumonia that results in intractable infection. Bronchogenic carcinoma and metastatic cancer involving the airways may produce this clinical presentation. Bronchioloalveolar carcinoma is a relatively common form of primary lung cancer that characteristically presents as a chronic infiltrate associated with cough, hypoxemia, shortness of breath, and mucus hypersecretion. This cancer has two distinct histological types with markedly different prognosis. The mucinous variety is much more likely to be multicentric and rapidly progressive whereas the nonmucinous variety may be localized. Lymphoproliferative diseases may also present in an infiltrative appearance. Kaposi's sarcoma infiltrating the lungs, particularly associated with acquired immune deficiency syndrome, presents a diagnostic dilemma because of the high incidence of pulmonary infection in these patients.

Acute severe asthma. How to recognize and respond to a life-threatening attack.

A disturbing increase in mortality from asthma has occurred over the past decade. Asthmatic patients who are over age 55 and have coexisting cardiac or pulmonary disease, those who have a history of mechanical ventilation, and those who require continuous outpatient use of corticosteroids to control symptoms have an increased risk of severe or fatal exacerbations of their disease. Patients hospitalized for severe asthma should receive inhaled beta 2-adrenergic agonists for bronchodilation and intravenous corticosteroids. Patients requiring mechanical ventilation have about a 20% incidence of pneumothorax and an enhanced risk of nosocomial pneumonia, and their mortality rate approaches 20%. Once severe asthma improves, patients must have their outpatient regimen strengthened by the use of oral corticosteroids, inhaled corticosteroids, and/or inhaled cromolyn sodium (Intal).

Repetitive nocturnal arterial oxygen desaturation and silent myocardial ischemia in patients presenting for vascular surgery.

OBJECTIVE: To determine whether nocturnal respiratory abnormality (cyclic oxygen desaturation and tachycardia) is associated with nocturnal myocardial ischemia in older individuals with ischemic heart disease. DESIGN: Non-invasive monitoring on a single occasion. SETTING: Tertiary care referral hospital. PATIENTS: Thirty four consecutive older (68.5 +/- 6 yrs) patients referred for elective abdominal or carotid reconstructive vascular surgery. RESULTS: Seven patients (21%) had moderately severe nocturnal respiratory abnormality, defined by more than 50 dips in arterial oxygen saturation and increases in heart rate during the night. Two of these seven had clinical risk factors for ischemic heart disease and had nocturnal myocardial ischemia. Ten patients (29%) developed ischemia at some time during the study, of whom seven hand known ischemic heart disease, hypertension, and/or angina. Those with increased nocturnal ischemia showed very low frequency (1-2 cycles per minute) cyclic heart rate oscillations and repetitive nocturnal episodes of arterial oxygen desaturation, similar to patients with sleep apnea. CONCLUSION: Repetitive nocturnal cyclic arterial desaturation and cyclic increases in heart rate are associated with nocturnal myocardial ischemia in individuals with clinical risk factors for ischemic heart disease. Further investigation in a large patient sample utilizing non-invasive monitoring of saturation, heart rate, and blood pressure may provide definitive evidence regarding causation of some of the nocturnal myocardial ischemia occurring in older individuals with vascular disease.

A coaxial gas delivery system for laser bronchoscopy.

This paper discusses the development and implementation of a prototype coaxial gas delivery system for laser bronchoscopy. The design of the system is presented including a detailed description of the device's theory of operation and construction. The system's medical application in laser bronchoscopy is described.

Late postoperative nocturnal dips in oxygen saturation in patients undergoing major abdominal vascular surgery. Predictive value of pre-operative overnight pulse oximetry.

Twenty-four patients (23 male) who presented for aortic reconstructive surgery were studied with pulse oximetry on a pre-operative night and during the first five postoperative nights. Patients with five or more dips in oxygen saturation of greater than 4% (with a prompt recovery back toward baseline of 3% or more) per hour of monitoring were classified as having a significant abnormality of respiration. Pre-operatively, four of 24 patients (17%) demonstrated such an abnormality. Postoperatively, 12 patients (50%) met these criteria on at least one of the first five postoperative nights and six of these had two or more nights with severe episodic hypoxaemia. Frequent severe episodic dips in arterial oxygen saturation (to less than 85% saturation) occurred in the late postoperative period at a time when oxygen therapy would usually have been discontinued. Pre-operative overnight pulse oximetry studies fail to predict the development of abnormal respiratory patterns in the postoperative period in the majority of patients.

Postoperative hypoxaemia after major abdominal vascular surgery.

We have studied the severity and duration of nocturnal hypoxaemia before operation and for the first five nights after operation after elective major abdominal vascular surgery. Oxygen supplementation was almost 100% effective in keeping oxygen saturation greater than 90% during the early postoperative period; however, 50% of patients spent prolonged periods with an SpO2 less than 85% during at least one night after operation. The risk of severe hypoxaemia persists well beyond the current prescription of supplementary oxygen in these high risk patients. A significant association exists between the mean preoperative overnight saturation value and the nocturnal saturation observed subsequently in the later postoperative period.

Postoperative obstructive sleep apnoea. Haemodynamic effects of treatment with nasal CPAP.

A 74-year-old man presenting for aortic reconstructive surgery showed severe, previously undiagnosed obstructive sleep apnoea during overnight oximetry monitoring before operation. Postoperatively, in the first 4 hours following extubation, he suffered 238 episodes of respiratory obstruction. These events were associated with frequent arousals, large fluctuations in systolic and diastolic blood pressure. Administration of nasal continuous positive airways pressure abolished the obstructions and allowed an uninterrupted night's sleep, with a significantly reduced blood pressure. Subsequent dips in oxygen saturation as a result of respiratory obstruction recurred on the fifth postoperative night. We conclude that pre-operative overnight oximetry may be useful in identifying those patients at risk of postoperative upper airway obstruction. Use of nasal continuous positive airway pressure may prevent the occurrence of early postoperative obstruction and the associated haemodynamic changes.

Haemodynamic effects of periodic ventilation: abolition with supplementary oxygen.

A 63-yr-old man was noted to breathe with a periodic pattern of ventilation during sleep, both before and after operation for coronary artery grafting, and 6 weeks later after aortic aneurysm repair. Periodic ventilation was associated with cyclic oxygen desaturations and increases in heart rate and arterial pressure. Administration of oxygen was found to abolish consistently the periodic pattern and the associated haemodynamic changes.

Atypical pneumonia and environmental factors. Where have you been and what have you done?

The wide variety of conditions described in this paper emphasizes the potential importance of occupational, environmental, travel, and avocational history in the correct diagnosis of lung disease (Table 3). The focus of attention in this paper is quite clearly North America and other developed countries. To expand this discussion to include illnesses limited to the underdeveloped regions of the world would require a treatise of tropical and geographic medicine. Many times, these "exotic" circumstances can be dismissed in relatively short order. Detailed interrogation of a sick patient with pneumonia will be impossible in many cases. Nevertheless, if the clinical picture does not fall rapidly in line with the more common causes of pneumonia, consideration of these "unusual" causes of the syndrome may be essential.

Zeolite exposure and associated pneumoconiosis.

Naturally occurring zeolite minerals are aluminum silicates widespread in the earth's crust. Several of these minerals have fibrous forms and have been implicated as a possible cause of benign and malignant diseases of the lung and pleura in Turkey. This report describes a patient, living in an area of Nevada rich in zeolites, who presented with idiopathic pleural thickening and pulmonary fibrosis associated with extensive pulmonary deposition of zeolites.

Intratracheal fire ignited by the Nd-YAG laser during treatment of tracheal stenosis.

Intratracheal combustion of a fiberoptic bronchoscope and an endotracheal tube occurred during the treatment of severe tracheal stenosis with the neodymium-YAG laser. This recognized hazard of CO2 laser surgery has not been reported previously with the use of the Nd-YAG laser. Fire hazard is inevitable when a laser is used in the airway, but the risk can be diminished. Rapid removal of the burning endoscope and endotracheal tube is essential to prevent serious complications.

Sister chromatid exchange frequency in asbestos workers.

In vitro cytogenetic studies of amosite, chrysotile, and crocidolite asbestos have shown that these fibers may induce chromosome abnormalities and an elevated sister chromatid exchange (SCE) rate in mammalian cells. Twenty-five asbestos insulators (6 with radiographic asbestosis) were compared to 14 controls frequency matched for age and were found to have a marginally increased SCE rate in circulating lymphocytes with increasing years of exposure (P= 0.057). There was a significant association between SCE rate and smoking (P=0.002) after controlling for years of asbestos exposure and age. Smoking asbestos insulators had the highest SCE rate. Sister chromatid exchanges in chromosomes of group A, i.e., the group with the longest chromosomes, were significantly associated with asbestos exposure and cigarette smoking, with an interaction between the two.