The effect of bronchofiberscopic examination on oxygenation status

An evolving role for endobronchial ultrasonography in the intensive care unit

Endobronchial ultrasound (EBUS) bronchoscopy is an established minimally-invasive modality for visualization, characterization, and guidance of sampling of paratracheal and parabronchial structures and tissues. In the intensive care unit (ICU), rapidly obtaining an accurate diagnosis is paramount to the management of critically ill patients. In some instances, diagnosing and confirming terminal illness in a critically ill patient provides needed closure for patients and their loved ones. Currently available data on feasibility, safety, and yield of EBUS bronchoscopy in critically ill patients is based on single center experiences. These data suggest that in select ICU patients convex and radial probe-EBUS bronchoscopy can serve as useful tools in the evaluation of mediastinal lymphadenopathy, central airway obstruction, pulmonary embolism, and peripheral lung lesions. Barriers to the use of EBUS bronchoscopy in the ICU include: (I) requirement for dedicated equipment, prolonged procedure time, and bronchoscopy team expertise that may not be available; (II) applicability to a limited number of patients and conditions in the ICU; and (III) technical difficulty related to the relatively large outer diameter of the convex probe-EBUS bronchoscope and an increased risk for adverse cardiopulmonary consequences due to intermittent obstruction of the artificial airway. While the prospects for EBUS bronchoscopy in critically ill patients appear promising, judicious patient selection in combination with bronchoscopy team expertise are of utmost importance when considering performance of EBUS bronchoscopy in the ICU setting.

Defining a Ventilation Strategy for Flexible Bronchoscopy on Mechanically Ventilated Patients in the Medical Intensive Care Unit

BACKGROUND

Flexible bronchoscopy (FB) in intubated patients on mechanical ventilation increases airway resistance. During FB, two ventilatory strategies are possible: maintaining tidal volume (VT) while maintaining baseline CO2 or allowing reduction of VT. The former strategy carries risk of hyperinflation due to expiratory flow limitation with FB. The aim of the authors was too study end expiratory lung volume (EELV) during FB of intubated subjects while limiting VT.

METHODS

We studied 16 subjects who were intubated on mechanical ventilation and required FB. Changes in EELV were measured by respiratory inductance plethysmography. Ventilator mechanics, EELV, and arterial blood gases, were measured.

RESULTS

FB insertions decreased EELV in 64% of cases (-325±371 mL) and increased it in 32% of cases (65±59 mL). Suctioning decreased EELV in 76% of cases (-120±104 mL) and increased it in 16% of cases (29±33 mL). Respiratory mechanics were unchanged. Pre-FB and post-FB, PaO2 decreased by 61±96 mm Hg and PaCO2 increased by 15±7 mm Hg.

CONCLUSIONS

There was no clinically significant increase in EELV in any subject during FB. Decreases in EELV coincided with FB-suctioning maneuvers. Peak pressure limiting ventilation protected the subject against hyperinflation with a consequent, well-tolerated reduction in VT, and hypercapnea. Suctioning should be limited, especially in patients vulnerable to derecruitment effect.

Fiber-optic bronchoscopy and volume-cycled mouthpiece ventilation for a patient with multiple sclerosis and ventilatory failure

Fiber-optic bronchoscopy supported by continuous or bilevel positive airway pressure has helped patients with hypoxemic or hypercapnic respiratory failure avoid respiratory complications. The authors describe a case of a 57-yr-old man with multiple sclerosis with a vital capacity of 250 ml (5% of predicted normal) who was using continuous noninvasive intermittent positive pressure ventilatory support when he underwent bronchoscopy while receiving continuous noninvasive intermittent positive pressure ventilatory support via a 15-mm angled mouthpiece interface. He was switched from a nasal to a 15-mm angled mouthpiece interface for continuous noninvasive intermittent positive pressure ventilatory support for the procedure. Simple mouthpieces may be useful alternatives to other facial interfaces for ventilatory support during bronchoscopy because of patient comfort and operator convenience.

Management of complications from diagnostic and interventional bronchoscopy

From the humble beginnings as a mere curiosity, the art of bronchoscopy has progressed at a rapid pace. The millennium ushers in new technologies and refinements in established techniques to facilitate early detection of cancer, precise targeting of pulmonary nodules and infiltrates, near-total staging of the mediastinum with combined endoscopic modalities and more effective palliation of inoperable tumours. Bronchoscopists are faced with an increasing myriad of tools and equipment, each promising to carry out better than the previous. It is opportune to review the complications of established bronchoscopic techniques and how to manage them as well as new complications associated with novel technologies. In this article, we provide a concise overview of diagnostic and therapeutic bronchoscopic modalities, discussion of associated complications and their management strategies.

Functional implications of BAL in the presence of restrictive or obstructive lung disease

Most of the complications associated to bronchoscopy are related to changes of the respiratory function during or after its performance. Prevention of complications should be achieved by understanding the effects of bronchoscopic procedures and their relation to the pulmonary function deterioration. Previous studies regarding the functional impairment caused by bronchoalveolar lavage (BAL) were mostly limited by the presence of interferent factors such as sedative drugs. Furthermore, it is not clear whether or not patients with different ventilatory disturbances present the same functional response to bronchoscopy and BAL. The aim of this study was to determine the additional effects of BAL over the respiratory function deterioration related to bronchoscopy in patients with different respiratory function profiles (normal, restrictive and obstructive). Forty patients submitted to bronchoscopy without premedication were divided into four groups: group I-normal pulmonary function submitted to basic bronchoscopy; group II-bronchoscopy in combination with BAL, subdivided according to pulmonary function: group IIa (normal function), group IIb (restrictive ventilatory disturbances) and group IIc (obstructive ventilatory disturbances). Spirometry was made before and after the bronchoscopic procedure. Baseline hemoglobin saturation was compared to the lowest level during the procedure. Functional worsening caused by the procedure was observed with a decrease in forced vital capacity (FVC), forced expiratory volume in the first second (FEV(1)) and Hemoglobin saturation in all groups. Comparison between groups showed no significant difference regarding the changes in FVC (P=0.8324), FEV(1) (P=0.6952) and hemoglobin saturation (P=0.5044). We conclude that standardized BAL, like the one used in our study, does not result in an increased risk for ventilatory impairment compared to bronchoscopy itself, independently of the presence of previous respiratory disease.

Prospective randomized trial comparing oxygen administration during nasal flexible bronchoscopy : oral vs nasal delivery

STUDY OBJECTIVES

To determine the optimal method of delivering supplemental oxygen during flexible bronchoscopy (FB).

DESIGN

Prospective study.

SETTING

University medical center.

PATIENTS

Ninety-seven consecutive patients undergoing outpatient nasal FB during a 7-month period.

INTERVENTION

During FB, delivery of oxygen was alternated weekly and administered by nasal cannula either nasally (52 patients) or orally (45 patients). Prior to the procedure, patients completed a questionnaire regarding oral or nasal breathing preferences, history of sinus disease, allergy history, and perceived degree of nasal congestion.

RESULTS

Comparison of oxygen delivery groups demonstrated no significant difference in oxygen requirements (4.1 L/min nasal vs 3.8 L/min oral, p = 0.63), overall saturation nadir (90.9% nasal vs 91.4% oral, p = 0.85), or average saturation (95.8% nasal vs 95.7% oral, p = 0.57). No correlation between subjective symptoms or sinus or allergy history was found for oxygen requirements, average saturation, or saturation nadir.

CONCLUSIONS

These data suggest that during nasal FB, no discernible difference exists between administration of oxygen using cannulas placed either nasally or orally.

Sedation in outpatient bronchoscopy

Bronchoscopy is a procedure that is likely to provoke anxiety as the patient is surrounded by monitoring and bronchoscopy equipment, and care is administered by strangers who perform intimate, invasive, and sometimes, painful procedures. Sedation is needed, therefore, to allay anxiety and reduce stress, improve patient comfort and co-operation, provide amnesia and facilitate the bronchoscopic procedure. In this review we try to summarize the current knowledge on currently used sedation protocols with special reference to the commonly used pharmacological agents. We believe sedation should be used routinely in fiberoptic bronchoscopy in order to achieve a safe and pleasant procedure for both the patient and the pulmonologist.

Detection of bronchial preneoplastic lesions and early lung cancer with fluorescence bronchoscopy: a study about its ambulatory feasibility under local anaesthesis

BACKGROUND

Autofluorescence bronchoscopy (AB) enhances the bronchoscopist's ability to diagnose bronchial preneoplastic lesions and early cancer. We undertook a study to assess its feasibility and performance under local anaesthesia on a real ambulatory mode.

METHODS

Thirty-four consecutive patients at very high risk for lung cancer were prospectively studied by AB under local anaesthesia, without any sedation. Lidocaine doses, time, oxygen saturation, peak expiratory flow (PEF) and the number of cough episodes were measured. Continuous assessment of the respiratory sensation was obtained with a visual analog scale. A total of 172 biopsies were performed in abnormal and normal areas.

RESULTS

The procedure was long-lasting (mean +/- SD: 26.6 +/- 6.0 min), required high total doses of Lidocaine (660 +/- 107 mg) without any significant side effect, and was associated with significant decreases in O2 saturation from 98.5 +/- 1.4 to 96.1 +/- 2.5% and in PEF from 380 +/- 96 to 310 +/- 78 l/min. However, the cough counts were moderate and the majority of patients reported no respiratory discomfort. 62 hyperplasia, metaplasia, dysplasia and carcinoma in situ (CIS) were detected and the relative sensitivity of AB +/- white-light bronchoscopy (WLB) versus WLB alone was 3.75 for intraepithelial lesions corresponding to moderate dysplasia or worse.

CONCLUSIONS

AB, a procedure that increases our ability to recognize preneoplastic lesions and early lung cancer, can be performed under local anaesthesia, without systemic sedation in patients at very high risk for lung cancer.

Patient satisfaction with conscious sedation for bronchoscopy

STUDY OBJECTIVE

Bronchoscopic technique is not standardized. Controversies exist with regard to premedication with sedatives before the test. To evaluate safety and efficacy of conscious sedation, we studied 100 randomized patients undergoing diagnostic bronchoscopy; patients received premedication with lidocaine spray and atropine sulfate i.m. (nonsedation group; 50 patients) or lidocaine spray, atropine i.m. and diazepam i.v. (sedation group; 50 patients).

METHODS AND RESULTS

Monitoring during flexible fiberoptic bronchoscopy included continuous ECG and pulse oximetry. The procedure could not be completed in six patients. None received premedication with diazepam; among the patients who ended the examination, tolerance to the examination (visual analogue scale, 0 to 100; 0 = excellent; 100 = unbearable) was better in the sedation group. Low anxiety, male sex, but not age were also associated with improved patient tolerance to the test. Oxygen desaturation occurred in 17% of patients, and it was not more frequent after diazepam treatment.

CONCLUSIONS

In our study, sedation had a beneficial effect on patient tolerance and rarely induced significant alterations in cardiorespiratory monitoring parameters.

Bronchoalveolar lavage causes decrease in PaO2, increase in (A-a) gradient value and bronchoconstriction in asthmatics

The aims of this study were to (1) record the changes of (arterial oxygen partial pressure) PaO2, (arterial carbon dioxide partial pressure) PaCO2, (percentage saturation of haemoglobin with oxygen in arterial blood) SaO2 and alveolar-arterial (A-a) oxygen gradiant resulting from bronchoalveolar lavage (BAL) in asthmatic and normal subjects; (2) measure changes in forced expiratory volume in 1 s (FEV1), vital capacity forced (FVC) associated with BAL; and (3) assess possible predictive factors for the degree of hypoxaemia and impairment of spirometry resulting from BAL. Bronchoscopy and BAL (150 ml) were performed in 24 asthmatics and 15 healthy subjects. Serial arterial blood samples (radial artery) were obtained in all subjects: T1 and before T2 after local anaesthesia; T3 at end of bronchoscopy; T4 after BAL and 5 min, 15 min, 1 h, 2 h, 8 h and 24 h (T5-T10) after the procedure, FEV1 and FVC were measured immediately before and 5 min afer bronchoscopy. Baseline PaO2 was lower in asthmatics (10.2 +/- 0.8 kPa) than in healthy subjects (10.8 +/- 0.8). Both groups showed a significant decrease in PaO2, and a significant widening in (A-a) oxygen tension gradiant at T3-9, with respect to T1 (P < 0.05). PaO2 reached a significantly lower value in asthmatics (7.1 +/- 0.6 kPa) than in HS (7.7 +/- 0.5; P < 0.05). In asthmatics, FEV1, FVC and the ratio FEV1/FVC decreased significantly after BAL (P < 0.001). In healthy subjects, FEV1 and FVC decreased significantly (P < 0.001), whereas FEV1/FVC did not. The fall in FEV1 after BAL was significantly greater in asthmatics (32.4 +/- 10.0%) than in healthy subjects (17.7 +/- 4.6; P < 0.001). Severity of asthma, basline FEV1 or initial PaO2 did not predict the degree of hypoxaemia or the fall of FEV1. It is concluded that BAL causes more severe hypoxaemia and a greater decrease in FEV1 in asthmatics compared to healthy subjects, strongly supporting the recommendation of special caution and careful monitoring when BAL is undertaken in asthmatics.

Myocardial ischemia in sedated patients undergoing fiberoptic bronchoscopy

STUDY OBJECTIVE

To study the incidence of myocardial ischemia and related hemodynamic alterations in sedated patients undergoing fiberoptic bronchoscopy (FOB).

DESIGN

Prospective study.

SETTING

Tertiary care, university hospital.

PATIENTS

Twenty-nine patients, age 50 years or older, undergoing elective FOB.

INTERVENTIONS

Myocardial ischemia was assessed by continuous ECG monitoring beginning 30 min before, and until 2 h after FOB.

MEASUREMENTS AND RESULTS

During FOB, there was a significant rise in heart rate (89+/-3 [mean+/-SE] to 120+/-4 beats/min) and fall in oxygen saturation (95+/-1 to 90+/-1%). There was no significant rise in systolic or diastolic BP. Five patients (17%) had myocardial ischemia during FOB that lasted 20+/-8 min. Their demographic and pre-FOB characteristics were not different from the other patients. Compared to baseline values, a significant rise in heart rate, a fall in oxygen saturation, and no significant change in BP were observed during FOB in patients, both with or without ischemia. Although not statistically significant, ischemia was associated with more protracted procedures.

CONCLUSIONS

Myocardial ischemia may develop in elderly patients undergoing FOB. This observation encourages the routine use of ECG and oximetry during FOB, allowing for early intervention to prevent the dangerous combination of hypoxia, tachycardia, and myocardial ischemia. Moreover, this study suggests that methods to ensure oxygenation during FOB should be adhered to, and that the routine administration of atropine should be reconsidered.

The role of ECG monitoring during bronchoscopy in lung cancer patients

Bronchoscopy, as an endoscopic technique, is associated with respiratory and circulatory disorders. Cardiac rhythm disorders are the most common cardiovascular complications of bronchoscopy. In order to study ECG changes during bronchological procedures, ECG monitoring was undertaken (30 min before, during and 30 min after bronchoscopy) in 100 patients, 76 with bronchial carcinoma and 24 suffering from some other pulmonary disease. Within the same intervals PaO2, PaCO2 and pH were recorded. All recorded arrhythmias were classified as minor and major. According to arrythmia noted during bronchoscopy, patients were divided into two groups: group 1 comprised 70 patients without arrythmia or with minor arrythmia (70%) and group 2, 30 patients with major arrythmia (30%). No significant difference was noted in associated cardiac disease, cardiological medication, blood pressure, pulse rat, PaO2, PaCO2 and pH (P < 0.05). The only statistically significant difference between the two groups of patients was related to localization of tumour in the lungs. We could not correlate the occurrence of major arrythmia during bronchoscopy in patients with lung carcinoma with any underlying cardiopulmonary condition. Significant differences were noted in effects of tumour localization, i.e. major arrhythmias are more common and more dangerous in cases of tumours of the left bronchial trunk (possible bronchoscopic stimulation of the left stellate ganglion), and we therefore believe that ECG monitoring is desirable in these cases for the early detection and appropriate management of haemodynamically dangerous arrhythmias.

The role of bronchoalveolar lavage in the diagnosis of bacterial pneumonia

Bronchoalveolar lavage (BAL) has become an invaluable diagnostic tool with important clinical implications in both opportunistic infections and the pulmonary pathology of immunologic disease. Until recently, the use of BAL was limited primarily to two areas: the study of interstitial lung diseases and the diagnosis of lung infections by opportunistic microorganisms in severely immunocompromised patients with lung infiltrates. Over the past decade, the use of BAL has been expanded to include the conventional diagnosis of bacterial pneumonia in non-immunocompromised patients. In the past, different clinical studies proposed using BAL to quantify cultures in the sample obtained as a means of increasing the tool's effectiveness. Recent developments have led to a number of newer applications of BAL, such as bronchoscopic BAL, non-bronchoscopic BAL and protected BAL. The most important use of BAL in the non-immunocompromised patient is the diagnosis of pneumonia in the mechanically ventilated patient.

Sedation for fibre optic bronchoscopy

Most current sedative regimens for fibre optic bronchoscopy use an opioid, a benzodiazepine or a combination of both. This study compares midazolam (M) (a benzodiazepine), alfentanil (A) (an opioid) and a combination of both drugs (M+A). One hundred and three patients were randomized in double-blind manner into groups M(35), A(33) and M+A(35). The number of coughs, number of additional aliquots of lignocaine and duration of the procedures were recorded along with oxygen desaturation. The patient's level of discomfort was assessed by patient and bronchoscopist and expressed as a visual analogue score. There were significantly fewer coughs per minute in Group A compared with Group M (P = 0.0053), and significantly less lignocaine was required in Group A (P = 0.005) and in Groups M+A (P < 0.002) compared with Group M. There was no significant difference in the assessment of discomfort between the groups. There was a trend for Group M+A to desaturate more than the other two with a significant difference between desaturation in Group M+A and Group A (P = 0.033). Alfentanil is a more effective anti-tussive agent than midazolam for outpatient fibre optic bronchoscopy. The combination of alfentanil and midazolam does not provide any better anti-tussive effect and may have the risk of a greater degree of desaturation secondary to increased sedation.

Cardiopulmonary effects of bronchoalveolar lavage in critically ill patients

Bronchoalveolar lavage (BAL) has been proposed as a useful procedure for bacteriologic diagnosis of lower respiratory tract infection in mechanically ventilated patients. To determine the cardiopulmonary effects of this procedure and to identify the patients at risk of poor tolerance, 30 critically ill ventilated patients suspected of having pneumonia were studied. Hemodynamic and gas exchange parameters were continuously recorded using an arterial catheter, a Swan-Ganz catheter with SvO2 display, and a pulse oximeter. In addition to the basal sedation required by these patients, midazolam, 0.1 mg/kg intravenously, was administered 5 min prior to bronchoscopy. A moderate increase (10 percent from basal values) in heart rate, mean arterial pressure, and cardiac index was recorded at each measurement during the procedure. A marked decrease in PaO2 was observed during bronchoscopy associated with an increase in oxygen consumption. Maximal changes in SaO2 and SvO2 were recorded at the end of BAL. Two hours after the end of BAL, PaO2 values were still 20 percent lower than pre-BAL values in 40 percent of the patients. We conclude that BAL can be performed safely in most critically ill ventilated patients who have stable hemodynamic and ventilatory parameters. However, none of the recorded parameters allows identification of the patients at risk of poor tolerance of the procedure.

Effects of consecutive protected specimen brushing and bronchoalveolar lavage on gas exchange and hemodynamics in ventilated patients

OBJECTIVE

To assess cardiovascular effects and the oxygenation status of mechanically ventilated patients undergoing protected specimen brushing (PSB) and bronchoalveolar lavage (BAL) under fiberoptic bronchoscopy (FOB).

DESIGN

A prospective study.

SETTING

Polyvalent intensive care unit in a university hospital.

PATIENTS

Twelve consecutive, critically ill, intubated, and mechanically ventilated patients with hemodynamic failure requiring invasive monitoring with an indwelling radial artery catheter and indwelling Swan-Ganz catheter were included in the study.

INTERVENTIONS

Hemodynamic measurements, arterial and mixed-venous blood gas analyses, and arterial blood lactate analysis were performed before and at the end of a 10-min period of mechanical ventilation with a fractional concentration of oxygen in the inspired gas (FIO2) of 1.0. The same measurements and blood samplings were repeated at the end of the PSB procedure, at the end of the BAL procedure, and 1 h after the end of the BAL. During the study period the ECG, arterial oxygen saturation (SaO2), and mixed-venous oxygen saturation (SvO2) were continuously monitored.

MAIN RESULTS

A moderate increase in both mean arterial pressure and mean pulmonary arterial pressure was observed during the FOB procedure (p < 0.05). One hour after the end of BAL, the PaO2 decreased when compared with values recorded at the beginning of the procedure with the same FIO2 (p < 0.05). An increase in intrapulmonary shunt was observed at the end of BAL (p < 0.01). A moderate increase in PaCO2 was also observed after PSB (p < 0.05) and after BAL (p < 0.01). Monitoring of SaO2 permitted us to observe a significant and sustained decrease after the end of the FOB procedure from 10 to 60 min. The decrease in SvO2 was less pronounced but reached statistical significance.

CONCLUSIONS

We conclude that PSB and BAL under FOB are well tolerated in critically ill, mechanically ventilated patients with hemodynamic disturbances requiring inotropic or vasopressor agents (or both); however, a modest impairment in arterial oxygenation was observed after the end of the FOB procedure.

Safety of bronchoalveolar lavage and bronchial biopsies in patients with asthma of variable severity

The safety of fiberoptic bronchoscopy, bronchoalveolar lavage (BAL), and bronchial biopsies has been questioned in asthma, and current recommendations indicate that bronchoscopies should only be performed in mild to moderate asthma. Moreover, in most studies patients receive premedication with nebulized bronchodilators that may enhance the safety of the procedures. The purpose of this study was to determine (1) whether the overall safety of fiberoptic bronchoscopy, BAL, and bronchial biopsies in mild to moderate asthma could be extended to patients with more severe asthma and (2) whether these procedures are safe without premedication with nebulized bronchodilators. A group of 50 patients with asthma of variable severity (FEV1 ranging from 37 to 107% of predicted values) and 25 healthy volunteers were studied. Bronchoscopy, BAL (250 ml), and four bronchial biopsies were performed in a standardized manner, without premedication with a nebulized bronchodilator, by the same investigator. Safety was assessed by clinical follow-up, continuous recording of arterial oxygen saturation during the procedure with a digital oximeter, and measuring FEV1, FEF25-75, and FVC just before and 5 min after bronchoscopy. Arterial oxygen saturation decreased in asthmatic patients from 97% (range 91 to 99%) (T1) to 92% (range 79 to 98%) (T8) (ANOVA, Fisher's PLSD) and in control subjects from 97% (range 94 to 99%) (T1) to 93% (range 88 to 98%) (T8) (ANOVA, Fisher's PLSD). The fall in arterial oxygen saturation was not significantly different between asthmatic and normal subjects, and there was no correlation between arterial oxygen desaturation and the severity of asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Bronchoalveolar Lavage on Gas Exchange in Patients with Diffuse Lung Disease and Respiratory Failure

The effect of fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) on arterial oxygenation was examined in 22 patients with acute respiratory failure requiring mechanical ventilatory support. Arterial blood gases were determined immediately prior to BAL and at 15, 60, 120, and 360 minutes following BAL. PaO2/FIO2 decreased at 15 minutes and continued to decrease to approximately 33% below the baseline value at 2 hours. PaO2/FIO2 then remained constant over the remainder of the 6-hour study period. No substantial changes in FIO2, level of positive end-expiratory pressure, or intravenous pressor requirements occurred during the period of observation. Patients with lower pre-BAL PaO2/FIO2 ratios showed the least reduction in PaO2/FiO2 following BAL The BAL was diagnostic in 9 of 22 (41%) patients ( Pneumocystis carinii pneumonia in 5, bacterial pneumonitis in 2, and neoplastic involvement of the lung in 2). BAL was associated with mild deterioration of gas exchange but did not require significant changes in ventilatory or hemodynamic support for the 6-hour interval studied.

Diagnostic bronchoalveolar lavage in patients with pneumonia produces sepsis-like systemic effects

Fever following fiberoptic bronchoscopy occurs in 10-25% of the patients and its origin is not well understood. We prospectively examined changes in body temperature (T degrees), mean systemic arterial pressure (MAP) and oxygenation after 2 bronchoalveolar lavages (BAL, bronchoscopic and non-bronchoscopic) for 34 procedures in 25 intubated patients. In patients with pneumonia (11 investigations) we observed a rise in T degrees 3 h after bronchoscopic and non-bronchoscopic BAL, p less than 0.0001, a decrease in MAP, p = 0.008 and arterial oxygenation, p = 0.002. Of patients with pneumonia 73% had a rise in T degrees of more than 1 degrees C compared with only 17% of those without pneumonia (p = 0.005). Patients without pneumonia (23 procedures) had no significant changes in T degrees, MAP and arterial oxygenation following the 2 BAL procedures. Changes in T degrees correlated significantly with those in MAP, and with the level of endotoxin in bronchoscopic BAL fluid. These findings suggest that BAL in patients with pneumonia may cause intravascular translocation of toxins or mediators producing pyrogenic and hypotensive effects.

The diagnostic yield of bronchoscopy

The endoscopic examination of the tracheobronchial tree is most helpful in the diagnosis and staging of bronchial carcinoma. Tumors that are endoscopically visible may be confirmed in more than 95% of the cases. In localized peripheral tumors, the diagnostic yield of bronchoscopy is significantly lower; for peripheral metastases, only about 10%. In diffuse interstitial pulmonary diseases other than malignancies, some infections, and histiocytosis X, bronchoscopy including transbronchial biopsy is less successful.

Fiberoptic bronchoscopy in ventilated patients. Evaluation of cardiopulmonary risk under midazolam sedation

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).

Effect of fibreoptic bronchoscopy on pulmonary function

Several studies have shown that after fibreoptic bronchoscopy there may be a deterioration in lung function but it is not known whether this is due to the premedication, the topical anaesthetic, or the obstruction produced by the bronchoscope. The effects of each part of the procedure on spirometric measurements were studied in patients with lung disease and in normal non-smokers. Measurements were made after premedication (papaveretum and atropine) in seven patients and after topical anaesthesia of the bronchial tree (340 mg lignocaine) with and without the bronchoscope in the trachea in 21 patients and 10 control subjects. Premedication had no effect. In the normal subjects lignocaine produced significant falls in FEV1, forced vital capacity (FVC), peak expiratory flow (PEF), and peak inspiratory flow (PIF), and insertion of the bronchoscope caused further falls that were also significant. In the patients, however, although anaesthesia produced significant falls in FEV1, FVC, PEF, and PIF of similar magnitude to those found in the normal subjects, there was no further important decrease when the bronchoscope was inserted. It is concluded that the major effect of bronchoscopy on lung function is due to topical lignocaine in the airways, and in patients with lung disease (excluding asthma or a central obstructing carcinoma) the insertion of the bronchoscope causes little additional obstruction.

Effects of diagnostic procedures during fiberoptic bronchoscopy on heart rate, blood pressure, and blood gases

To investigate the effects of several endoscopic procedures like introduction of the bronchoscope, removal of the instrument, catheter suction, bronchoalveolar lavage and transbronchial biopsy on heart rate, systemic blood pressure, and transcutaneously measured blood gases 77 consecutive patients (age, 20-83 years) were studied. All patients received 101 O2/min via face mask during bronchoscopy. Sedation was performed with midazolam or diazepam. The different characteristics of each patient, e.g. age, sex, smoking habits, baseline values of heart rate and systemic blood pressure, underlying pulmonary disease and kind of premedication were examined separately to analyse their special effects on the course of bronchoscopy. During the fiberoptic bronchoscopy neither a slight decrease in transcutaneous pO2 nor a small increase in transcutaneous pCO2 led to a critical situation. Nevertheless it should be stressed that the time after removal of the instrument and finishing supplemental oxygen may be critical regarding hypoxia and hypercapnia especially in older patients with hypoxia being already present before starting the endoscopy. The hemodynamic indices did not change significantly. There was no difference between midazolam or diazepam concerning the parameters under study. If supplemental oxygen is given and adequate premedication is performed, monitoring of hemodynamics and blood gases during fiberoptic bronchoscopy is not necessary in patients without cardiovascular or respiratory risk.

Low frequency oscillatory ventilation through the suction channel of a pediatric bronchoscope

To determine whether low frequency oscillatory ventilation (LFOV) may be safely applied through the suction channel of a pediatric fiberoptic bronchoscope, we devised a system using a combination of jet ventilation and constant air suction, both delivered with a single interface valve. The system was tested on an in vitro lung model and on rabbits. With tidal volumes of 12 mL, inadvertent increase in functional residual capacity (FRC) measured in the lung model was minimal. All rabbits experienced marked hypoventilation (PaCO2 62 +/- 2 torr) on introduction of the bronchoscope, which promptly improved with administration of LFOV (PaCO2 41 +/- 4 torr). That baseline FRC remained stable indicated that air trapping did not occur. We conclude that LFOV improves ventilation in rabbits during bronchoscopy without causing air trapping. A similar system might be applied during bronchoscopy in full-term and premature infants, thus facilitating safer and more complete visualization of their airways and preserving the possibility of obtaining samples by suction.

Worsening oxygenation in the mechanically ventilated patient. Causes, mechanisms, and early detection

Hypoxemia or worsening oxygenation is a common problem in the ICU. Ventilator-related problems, patient-related problems, including progression of the underlying disease process or superimposed disorders, and interventions, procedures, and medications can all adversely affect the patient's oxygenation status. Each of these causes should be sought for in a rapid and expeditious manner and appropriate corrective actions taken.

Diagnostic and therapeutic possibilities for fibreoptic bronchoscopy in inhalation injury

Inhalation injury is a relatively common complication of burn injury requiring early attention with respect to diagnosis and therapy, and frequent assessments of the tracheobronchial status. Clinical, radiological and laboratory findings often cannot fulfil these needs. Therefore the advantages of flexible fibreoptic bronchoscopy (FFB) in diagnosis and therapy of respiratory tract injury are shown by these case reports.

Transbronchial biopsy during mechanical ventilation

The value and risk of transbronchial biopsy (TBB) was assessed in 15 cases requiring mechanical ventilation for progressive pulmonary infiltrates. TBB was diagnostic in five patients, and in two additional cases a diagnosis was made from the accompanying bronchial secretions. TBB results significantly altered the therapeutic management in seven cases. The alveolar-arterial gradient P(A-a)O2, widened by a mean of 110 mm Hg in nine patients; however, this change was transient and clinically insignificant. Three instances of reversible hypercapnia (mean of 15 mm Hg) occurred. Complications included self-limited bleeding in three cases and one tension pneumothorax. No fatalities were attributable to TBB. In these hemodynamically stable patients requiring mechanical ventilation for diffuse lung disease, TBB was performed safely and provided important data.

Tension ball valve mucus plug in asthma

This report describes a patient with status asthmaticus and respiratory failure in whom profound hypoxemia developed during mechanical ventilation. During the hypoxemic episode, breath sounds were absent over the left lung, and chest radiography revealed a hyperlucent left hemithorax with tension shift of the mediastinum to the right. The presence of lung markings in the left lung on radiography eliminated the possibility of tension pneumothorax and led to the diagnosis of tension mediastinal shift secondary to a ball valve obstruction by a central mucus plug. Bronchoscopic lung lavage removed the mucus plug, thereby correcting the hypoxemia. Recognition of this previously undescribed acute complication of mechanical ventilation in status asthmaticus is essential so that confusion with tension pneumothorax is avoided and appropriate therapy instituted.

[Fiberoptic bronchoscopy in intensive care medicine--functional efficacy and methodological side effects]

A prospective study was performed to determine the side effects of fiberoptic bronchoscopy on cardiopulmonary function, the influence of bronchial lavage on cardiopulmonary function, and the functional efficacy of fiberoptic bronchoscopy in obstructive atelectasis due to retained secretions. In 17 patients endotracheal intubation was immediately followed by a significant (P less than 0.01) rise in arterial, pulmonary artery and pulmonary capillary wedge pressure, heart rate, and cardiac output. There were no statistically significant differences in arterial blood gases and intrapulmonary right-to-left shunt. Two patients showed circulatory changes indicative of a heart insufficiency on the left side. A significant increase (P less than 0.001) in intrapulmonary right-to-left shunt from 12% to 17.5%, a significant decline in arterial oxygen tension of 15 mm Hg, and a significant increase of cardiac output from 6.4 to 7.71/min following saline solution lavage (20 ml in each bronchus) were observed in nine patients. The results indicate that bronchial lavage is the essential mechanism for the decline in arterial oxygen tension induced by fiberoptic bronchoscopy. In patients with unstable cardiopulmonary status, the cardiovascular response during bronchoscopy may be hazardous and the bronchoscopist should be aware of the pathophysiologic side effects involved. Fifteen therapeutic bronchoscopies were performed in five critically ill patients with obstructive atelectasis, due to retained secretions. Following the procedure, Qs/Qt declined from 23.9% to 15%, cardiac output from 9.3 to 7.31/min, and arterial Po2 increased from 58.9 to 70.9 mm Hg. The differences were statistically significant (P less than 0.0001). The therapeutic value of fiberoptic bronchoscopy in the treatment of obstructive atelectasis is demonstrated by the significant improvement in cardiopulmonary status.

A study of the use of ultrasonically nebulized lignocaine for local anaesthesia during fibreoptic bronchoscopy

The use of nebulized lignocaine, with and without intravenous diazepam premedication, was compared with lignocaine given by bolus in 52 patients undergoing fibreoptic bronchoscopy (FOB). Changes in airflow, cardiac rhythm, and transcutaneous PO2 were recorded, and patient acceptability, blood lignocaine levels, and the duration of the procedure were also monitored. Nebulized lignocaine alone provide adequate anaesthesia and the procedures were performed more quickly (P less than 0.05) than when bolus lignocaine was used. Nebulized lignocaine without diazepam was acceptable to the patients and was not associated with the significant (P less than 0.03) falls in transcutaneous PO2 which followed diazepam administration. Nebulized lignocaine, with and without, diazepam premedication is a safe, effective and acceptable method of inducing topical anaesthesia for FOB.

Alterations in pulmonary mechanics and gas exchange during routine fiberoptic bronchoscopy

Pulmonary function and arterial blood gases were measured in 35 patients undergoing routine diagnostic flexible fiberoptic bronchoscopy (FFB) either through an 8-mm endotracheal tube (ETT) or transnasally in order to investigate whether FFB changes lung function in a way which may explain why hypoxemia commonly occurs during this procedure. In these patients with moderate airway obstruction, functional residual capacity (FRC) increased significantly after inserting the ETT, after placing the FFB in the airway through the ETT, and after inserting the flexible bronchoscope transnasally. The mean increase in FRC was 30 percent in the intubated group before FFB insertion and 17 percent in the transnasal group. Removal of the FFB and ETT caused FRC to return toward the control value. Insertion of the ETT-FFB combination or transnasal FFB did not change PaO2 substantially, although following the examination, PaO2 was decreased significantly in the transnasal group but not in the intubated group. The PaO2 decreased significantly in both groups following removal of the ETT and transnasal FFB. These results suggest that placement of an FFB or ETT-FFB combination in the airway in spontaneously breathing subjects elevates FRC.

Sulfur dioxide-induced chronic bronchitis in beagle dogs

This study was done to produce a model of chronic bronchitis. Twelve beagle dogs were exposed to 500 ppm sulfur dioxide (SO2) for 2 h/d, 5 d/wk for 21 wk and 4 dogs were sham-exposed to filtered ambient air for the same period. Exposure effects were evaluated by periodically examining the dogs using chest radiographs, pulmonary function, tracheal mucous clearance; and the cellular and soluble components of bronchopulmonary lavage fluids. Dogs were serially sacrificed after 13 and 21 wk of exposure and after 6 and 14 wk of recovery. Clinical signs produced in the SO2-exposed dogs included mucoid nasal discharge, productive cough, moist rales on auscultation, tonsilitis, and conjunctivitis. Chest radiographs revealed mild peribronchiolar thickening. Histopathology, tracheal mucous clearance measurements, and lavage cytology were consistent with a diagnosis of chronic bronchitis. It is concluded that repeated exposure to 500 ppm SO2 for 21 wk produced chronic bronchitis in the beagle dog. Complete recovery occurred within 5 wk following cessation of SO2 exposure.

Hemodynamic effects of flexible fiberoptic bronchoscopy performed under topical anesthesia

Central hemodynamics and blood gases were measured continuously during flexible fiberoptic bronchoscopy performed under topical anesthesia in ten patients with restrictive lung disease. The procedure induced marked hemodynamic changes, which were maximal and similar in magnitude, during passage through the larynx and during suctioning. Mean arterial pressure increased by 30 percent, heart rate by 43 percent, cardiac index by 28 percent and mean pulmonary arteriolar occlusion pressure by 86 percent compared with pre-bronchoscopic control values. A slight fall in arterial oxygen tension was measured during bronchial suctioning and in the post-bronchoscopic period. Rate pressure product reached its highest value during bronchial suctioning at which time three of the ten patients developed ST-T-segment changes, implying that myocardial oxygen demand might have exceeded supply. It is suggested that the major mechanism behind the hemodynamic changes is a reflex sympathetic discharge caused by mechanical irritation of larynx and bronchi.

Transpleural lung biopsy by the thoracoscopic route in patients with diffuse interstitial pulmonary disease

Thoracoscopy was carried out in 81 cases of diffuse pulmonary disease in order to obtain lung tissue for biopsy. After we established artificial pneumothorax, the thoracoscope was introduced under local anesthesia, multiple biopsy specimens (theta 3 mm) were obtained under visual control, and an underwater sealed drain was left in place. The method was used to determine the cause of x-ray shadowing and respiratory distress in 26 immunocompromised patients. Within 2-48 hours, all biopsy specimens provided sufficient microbiologic and morphologic information to guide management, eg, specific antimicrobial drugs, decreasing or intensifying immunosuppression, or cytostatic therapy. Thoracoscopy was tolerated better than fiberoptic bronchoscopy, especially in hypoxic patients. Persisting or recurring pneumothoraces were seen in four patients and was not a major complication. In one very ill patient, the spleen was punctured accidentally before biopsy specimens were taken. Of 63 nonimmunocompromised patients, a histologic diagnosis was obtained in 57 (90 percent). In most of these patients, previous biopsy procedures had produced inconclusive results. Also in this group persisting or recurring pneumothoraces were seen in four patients, but closed eventually in a conservative way.

Modification of the effect of fiberoptic bronchoscopy on pulmonary mechanics

Thirty-three patients who were to undergo diagnostic fiberoptic bronchoscopy were studied. Pulmonary function tests were performed before the procedure, after topical lidocaine anesthesia, and immediately and four hours after bronchoscopy. Nine patients received aerosolized isoproterenol (Isuprel) before the topical anesthesia, and nine received aerosolized atropine. Pulmonary function tests were also performed after this intervention. In those patients receiving no premedication, all the indices of expiratory flow were reduced significantly immediately after bronchoscopy, and after the topical anesthesia, the FEV1 and FVC were significantly reduced. In the atropine groups, the FVC and FEV1 increased significantly after atropine, and increased still further following topical lidocaine anesthesia. By four hours after bronchoscopy, however, the midmaximal expiratory flow ws significantly reduced. In the isoproterenol group, only the FEV1 was significantly improved by the drug, and this improvement persisted even after the lidocaine. It decreased transiently immediately after bronchoscopy, but by four hours, was significantly above baseline again. The FVC diminished significantly immediately after bronchoscopy. It is concluded that fiberoptic bronchoscopy deleteriously affects pulmonary function and that inhaled isoproterenol or atropine largely protects against these deleterious effects.

Complications of bronchoscopy: comparison of rigid bronchoscopy under general anesthesia and flexible fiberoptic bronchoscopy under topical anesthesia

A prospective study of 4,595 bronchoscopic procedures performed over four years (1975 to 1978) on 2,143 patients with various bronchopulmonary diseases is described. Of the 4,595 procedures, 1,146 were performed with a flexible fiberoptic bronchoscope (Olympus BF-5B2 or BF-B2) under topical anesthesia with tetracaine and procaine, and 3,449 procedures were performed with a rigid bronchoscope under general intravenous anesthesia with hexobarbital (Evipan) using a modified Sanders' technique to ventilate the patients. Complications occurred in 235 procedures (5.1 percent). Major complications that threatened the patient's life and required intensive medical treatment, surgical intervention, or resuscitative measures occurred in 51 procedures (1.1 percent); deaths occurred after 6 procedures (0.1 percent). A comparison of the complications of rigid bronchoscopy and flexible fiberoptic bronchoscopy revealed significantly higher rates of complications of fiberoptic bronchoscopy attributable to toxic effects of tetracaine and of complications of rigid bronchoscopy associated with insufficient general anesthesia. With rigid bronchoscopy, the number of major complications induced by diagnostic manipulations through the bronchoscope and the total number of major complications were significantly higher than with flexible fiberoptic bronchoscopy.

Bronchopulmonary lavage cytology in the dog: normal findings

Fiberoptic bronchoscopy was used to obtain cytologic specimens from all lung lobes of 9 normal Beagle dogs. Three specimen collection techniques (bronchial lavage, bronchial brushing and bronchial pinch biopsy imprints) and two staining procedures (Wright-Giemsa and Papanicolaou) were used and evaluated. Bronchial lavage was the most satisfactory technique for collection of samples from the deep lung and bronchial brushings were preferred for potential bronchial tree mural lesions. Wright-Giemsa was the stain of choice because mast cells could not be identified and eosinophilic leukocytes could be identified only with difficulty in Papanicolaou stained specimens. Total and differential cell counts were determined on all bronchial lavages from all lung lobes in order to establish baseline reference values. Total nucleated cell counts ranged from 260-120/microliters. There were no significant differences among mean total nucleated cell counts for the different lung lobes. Mean total nucleated cell counts were between 420 and 630 cells/microliters. Approximately 95% of all nucleated cells in normal lavages were undifferentiated alveolar macrophages. Most of the other cells seen were neutrophils, eosinophils, possible globule leukocytes and mast cells. Ciliated and nonciliated epithelial cells comprised less than 1% of the total nucleated cell population.

The effect of fiberoptic bronchoscopy on cardiac rhythm

Cardiac rhythm was monitored in 70 patients prior to, during, and following fiberoptic bronchoscopic procedures. Minor abnormalities in rhythm were frequent. Major cardiac arrhythmias occurred in 11% (8/70) of the patients during the bronchoscopic procedure. All arrhythmias were self-limited and had no hemodynamic consequence. Patients with evidence of coronary arterial disease, chronic obstructive pulmonary disease, or previously known premature ventricular contractions were at no higher risk for developing major arrhythmias. Hypoxemia (arterial oxygen pressure less than 60 mm Hg) at the end of the procedure correlated significantly with the development of new major arrhythmias.

Intermittent positive pressure inflation during fiberoptic bronchoscopy

We describe a new technique for diagnostic fiberoptic bronchoscopic procedures under general anesthesia. The technique of inflation via nasotracheal catheter, which consists of using intermittent high inflating pressure for ventilation by passing a double catheter through the nose to the glottis and into the trachea, gave very satisfactory ventilaton, with high levels of oxygen in the blood. Intratracheal pressure was monitored continuously to guarantee safety, and pulmonary function was assessed before and after the procedure. Continuous electrocardiographic monitoring was used, and blood gas levels were determined at very frequent intervals. The use of infusions of methohexitone and succinylcholine (suxamethonium) provided adequate safe anesthesia and prompt recovery, with absence of recall of the procedure.