In the study, none of the test patients underwent bronchoscopy for resolution of atelectasis, whereas 42.9% control subjects underwent bronchoscopy. Three patients each in the test and control groups were advised bronchoscopy; however, consent could not be obtained in each of the six patients. If bronchoscopy was performed in all patients who failed noninvasive techniques to resolve atelectasis, 17.6% of patients in the test group versus 85.7% of patients in the control group would have required bronchoscopy. It can be projected from this study, that approximately 68% of all bronchoscopies may have been avoided in patients with atelectasis treated with KT+P. In addition, the KT+P group demonstrated a PaO2/FIO2 ratio that was significantly higher (P < 0.03) at days 3, 7, and 14 compared with the control group.
Manual Lung Inflation
With this treatment option, the patient is disconnected from the ventilator and is connected to a manual resuscitation bag. The lungs are inflated with large tidal volumes. High expiratory flows generated from the state of hyperinflation help to mobilize secretions. Different studies have shown no improvement 12 in lung compliance or oxygenation or an increase in lung compliance for as long as 2 hours in patients without pulmonary disease when hyperinflation was used with percussion. 13
Several studies have demonstrated that despite chest physiotherapy or bronchoscopy, the atelectatic segments may not expand. Kubota et al. 14 and Susini et al. 15 devised a curve-tipped catheter and a small-caliber balloon-tipped catheter respectively. The catheter was introduced through the nares or through an endotracheal tube. Fluoroscopic visualization was used in one study 15 while advancing the catheter. In that study, a 60-mL syringe was used to insufflate the atelectatic lobe. Compiling the data from these two studies, nonbronchoscopic techniques resulted in complete reexpansion of the atelectatic segments in 17 of 20 patients (85%) and partial reexpansion in the remaining three patients.
In summary, several studies have demonstrated that chest physiotherapy is an effective modality for the treatment of acute lobar atelectasis. The rate of resolution of atelectasis may be increased significantly by the combined and intensive application of these manual and mechanical therapies. 7 Manual chest physiotherapy, however, is labor intensive and may take up a substantial amount of health care providers' time. With the availability of specialty beds with the capability of providing lateral rotation to more than 40° on each side and percussion therapy, atelectasis may be resolved in a large number of patients without resorting to invasive techniques such as bronchoscopy. 11
FLEXIBLE BRONCHOSCOPY (FFB) FOR ATELECTASIS
Atelectasis, in the majority of patients, may be resolved with conventional chest physiotherapy. 14 Indeed, Marini et al. 16 showed no significant difference in the resolution of volume loss in postoperative patients receiving bronchoscopy or chest physical therapy. In the case of a lack of response to physical therapy (usually 24 to 48 hours), 17 or worsening atelectasis, bronchoscopy may be considered. FFB resulted in improvement in aeration on chest roentgenogram in 41% of 90 bronchoscopies performed for retained secretions. Clinical improvement was seen in only 19% patients. 18 A plausible explanation of the poor response is depicted in Fig. 3. In critically ill patients, for various reasons, there is a reduction in tidal volume and vital capacity. Reduction of functional residual capacity below closing volume results in closure of small airways, depletion of surfactant, and reabsorption of alveolar gases. This may result in the presence of air bronchograms in the subsegmented bronchi or beyond. Presence of distal air bronchograms connotes absence of secretions and hence failure of response to bronchoscopy. 17,19
When FFB is combined with vibrations and chest physiotherapy, the rate of complete resolution of atelectasis is approximately 71%. Partial improvement was noted in another 18% patients. 20
Another indication for FFB may be severe hypoxemia. Some authors have arbitrarily chosen a PaO2/FIO2 ratio of ≤ 100 as an indication for performing urgent FFB. 21
The complications associated with performing FFB for atelectasis are summarized in Table 4. 22
FFB is an invasive procedure that may be associated with complications in critically ill patients. The overall complications associated with FFB not involving transbronchial biopsy was 3 of 141 procedures (2.1%). 20 Hypoxemia, defined as an oxygen saturation of less than 90%, was observed in 29 of 147 procedures (19.7%) performed in mechanically ventilated patients.
The degree of hypoxemia during FFB may be as much as 20 mmHg. 23 The duration of hypoxemia may persist for 2 to 4 hours. However, the greater the amount of normal saline instilled for lavage during FFB, the more frequent the hypoxemia (as much as 23% of patients) 24 and the longer its duration (as long as 8 hours). 25 The issue of hypoxemia may assume greater clinical relevance in elderly patients who are hypoxemic to begin with and who have an advance directive that intubation and mechanical ventilation not be instituted.
An augmentation of cardiac output, mean arterial pressure, heart rate, and mean pulmonary artery occlusion pressure occurs during FFB. These effects are most pronounced during suctioning and usually last for approximately 15 minutes. 26 Significant atrial and ventricular arrhythmias were reported in 11% of patients in one series. 27
During passage of the bronchoscope and intrabronchial suctioning, irritant receptors in lower airways may be stimulated and may result in bronchospasm. 23 This may be particularly profound in the asthmatic, intubated patient with diffuse mucus plugging.
Cardiopulmonary arrest is rare, with an incidence of 0.01 to 0.5%. 22,28
In a study by Matsushima et al. 29 the passage of a standard 5.9-mm bronchoscope through an 8-mm cuffed endotracheal tube increased airway resistance approximately 11-fold. This may result in the development of dangerous intrinsic PEEP (average, 10.4 ± 9.3 cm H2O). It is therefore recommended by most investigators that extrinsic PEEP be discontinued before performing FFB. 26
In critically ill patients, the nose, oropharynx, or endotracheal tube may be colonized with pathogenic bacteria. The potential for the bronchoscope to act as a vehicle for translocation of these bacteria to the distal airways and result in nosocomial pneumonia is intuitively obvious.
Obtaining consent for a bronchoscopy may be difficult in specific subsets of patients. In 24 patients with atelectasis and respiratory failure, Raoof et al. 11 could not get consent or the Do Not Resuscitate order rescinded for performing bronchoscopy in six patients (25%).
In an editorial written by Prakash, 30 several risk factors were identified that predict complications during bronchoscopy. These include unstable angina, uncontrolled arrhythmias, refractory hypoxia, severe hypercarbia, severe bullous emphysema, severe asthma, severe coagulopathy, mechanical ventilation, high positive end-expiratory pressure, and lack of patient cooperation. Some or many of these factors may be present in patients undergoing bronchoscopy for atelectasis.
The actual cost of performing a bronchoscopy varies from hospital to hospital. The data are not readily available. An approximate estimation of costs was performed in a county hospital in New York in 1997. Assuming that an average bronchoscopy for resolving atelectasis takes 1 hour of the attending physician's time and 1.5 hours each of the pulmonary fellow's and bronchoscopy nurse's time, adding equipment used and sterilizing expenses, the cost for performing a bronchoscopy was estimated at $300 (US). The costs of renting specialty beds in the same hospital to provide KT+P were $180 (US)/day. 11 The expenses incurred in delivering manual chest percussion and suctioning and two hourly patient rotations is difficult to calculate. Knowledge of costs incurred in individual settings may be an important factor in choosing the procedure of choice.
Based on the current data, a proposed algorithm for management of pulmonary atelectasis is outlined in Fig. 4.
In conclusion, atelectasis is a common occurrence in critically ill patients. Atelectasis has notable effects on lung mechanics and gas exchange. If the reason for development of atelectasis is retained secretions, bronchoscopy may be preferred to less invasive techniques in the severely hypoxemic individual. If distal air bronchograms (subsegmental bronchi and beyond) are seen, patients may have alveolar collapse without retained secretions. In such cases, bronchoscopy is unlikely to be beneficial. The usefulness of bronchoscopy in resolving atelectasis is comparable with chest physical therapy (either manual or mechanical). Finally, bronchoscopy is an invasive procedure that has substantially more complications than chest physical therapy.
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