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Toilet bronchoscopy in the ICU 

Toilet bronchoscopy in the ICU
Chapter:
Toilet bronchoscopy in the ICU
Author(s):

Gianluigi Li Bassi

and Carles Agusti

DOI:
10.1093/med/9780199600830.003.0122
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date: 03 December 2020

Key points

  • Toilet bronchoscopy should only be applied when other less invasive methods of secretion removal have failed to dislodge retained mucus and revert to pulmonary atelectasis.

  • Toilet bronchoscopy is highly efficient when retained secretions are visible during the procedure, air-bronchograms are not present on the chest radiograph, and when indicated to reverse lobar atelectasis.

  • Potential complications associated with toilet bronchoscopy comprise hypoxaemia, cardiac dysrhythmia, haemodynamic instability and pulmonary haemorrhage.

  • Overall safety of the intervention is drastically enhanced through proper setting of the mechanical ventilator, adequate sedation and analgesia, and exhaustive monitoring of physiological parameters.

  • Specific patient populations on non-invasive mechanical ventilation can also benefit from a bronchoscopic approach to clear retained secretions.

Introduction

Retention of respiratory secretions is common in critically-ill patients [1]‌, and it may interfere with ventilation, impair gas exchange, predispose to respiratory infections, and lead to the development of lung atelectasis. Toilet bronchoscopy is a potentially therapeutic intervention to aspirate retained secretions within the endotracheal tube and airways and revert atelectasis. Aspiration of airway secretions is the most common indication to perform a therapeutic bronchoscopy in the intensive care unit (ICU) [2].

Toilet bronchoscopy efficacy

The reported efficacy of toilet bronchoscopy in removing retained secretions and reversing atelectasis ranges between 19 and 89%, according to the studied ICU population [3]‌. Toilet bronchoscopy is particularly beneficial when retained secretions are visible during the procedure and when air-bronchograms are not present at the chest radiograph [4]. It is also beneficial when there is an indication to reverse lobar atelectasis [5], rather than simply to remove accumulated mucus. In specific populations, the applied technique may be modified to enhance its efficacy. For instance, in patients with asthma, mucus is highly viscous because of an abnormal concentration of plasma proteins, DNA, cells, and proteoglycans, which results in an inability to remove secretions. In those patients, toilet bronchoscopy with concomitant broncho-alveolar lavage, with or without the use of mucolytics, achieves removal of distal mucus plugs [6]. Finally, some researchers advocate that the sole removal of mucus may not be sufficient to re-expand an atelectatic lobe. Tsao et al. [7] originally reported resolution of lobar atelectasis through selective intrabronchial toilet and air insufflation. A three-way port was connected to the bronchoscope working channel. One port was attached to an ambu bag and the other port was used to monitor insufflation pressure. The bronchoscope was wedged into each subsegment of the collapsed lobe to keep the airway pressure at 30 cmH2O for 1–2 minutes. These methods were slightly modified later on, through the connection of a standard 15-mm endotracheal tube connector to the bronchoscope working channel port (Fig. 122.1). To date, only one study [4] has compared the effects of chest physiotherapy with toilet bronchoscopy for the treatment of atelectasis in a small ICU population. Chest physiotherapy comprised of deep breathing or manual hyperinflation for 3 minutes, then coughing or tracheal suctioning and finally nebulization of saline, chest percussion, and postural drainage. In both groups, after 24 hours, atelectasis was reversed in 80% of the cases with no indication of advantages in the use of toilet bronchoscopy over less invasive approaches.

Fig. 122.1 Fibre optic bronchoscopy—ambu bag apparatus for selective segmental bronchial insufflation. Following intrabronchial mucus suctioning, the bronchoscope is wedged into each segment or subsegment of the atelectatic lobe and gas is slowly insufflated through the ambu bag into the bronchoscope working channel to achieve 30 cmH2O airway pressure for a few minutes. (a) 15-mm endotracheal tube connector; (b) ambu bag; (c) pressure manometer.

Fig. 122.1 Fibre optic bronchoscopy—ambu bag apparatus for selective segmental bronchial insufflation. Following intrabronchial mucus suctioning, the bronchoscope is wedged into each segment or subsegment of the atelectatic lobe and gas is slowly insufflated through the ambu bag into the bronchoscope working channel to achieve 30 cmH2O airway pressure for a few minutes. (a) 15-mm endotracheal tube connector; (b) ambu bag; (c) pressure manometer.

Courtesy Hugo Loreiro, MD Hospital Clinic, Barcelona, Spain.

Indications

Toilet bronchoscopy is specifically indicated for patients who present with significant retention of airway secretions and pulmonary atelectasis (Fig. 122.2). In critically-ill patients, mucus retention is frequent, because of immobilization, post-operative pain, weak cough, and muscle weakness. Additionally, in intubated ICU patients, mucociliary transport is drastically reduced [8]‌, and outward mucus clearance is not possible because of the endotracheal tube cuff inflated within the trachea. Patients with underlying diseases associated with overproduction of mucus and impairment of its clearance, such as asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis, and cystic fibrosis, may benefit from toilet bronchoscopy. In particular, mucus retention and potential benefits of toilet bronchoscopy in asthma should not be underestimated. In these patients, mucus is typically stationary within distal airways, as consistently corroborated in patients who die of status asthmaticus [9], and it is difficult to remove through suctioning. Finally, patients with neuromuscular diseases and ineffective cough seem to benefit from a bronchoscopic approach to clear secretions [10].

Fig. 122.2 Toilet bronchoscopy indication. (a) Chest radiograph of a tracheostomized critically-ill patient who was admitted for acute exacerbation of chronic obstructive pulmonary disease. The radiograph depicts extensive left lung atelectasis with no evidence of air-bronchograms. (b) Following unsuccessful chest physiotherapy, toilet bronchoscopy showed full obstruction of the left main bronchus by copious airways secretions.

Fig. 122.2 Toilet bronchoscopy indication. (a) Chest radiograph of a tracheostomized critically-ill patient who was admitted for acute exacerbation of chronic obstructive pulmonary disease. The radiograph depicts extensive left lung atelectasis with no evidence of air-bronchograms. (b) Following unsuccessful chest physiotherapy, toilet bronchoscopy showed full obstruction of the left main bronchus by copious airways secretions.

Contraindications and adverse effects

Toilet bronchoscopy is generally well tolerated by ICU patients and only a few absolute contraindications exist to its use (Box 122.1). Only personnel experienced in the procedure, who are trained to recognize and treat all potential complications, should perform the intervention. The risks associated with the procedure should always be weighed against the potential benefits. In general, toilet bronchoscopy should only be applied when other less invasive methods of secretion removal have failed to remove mucus plugging and revert atelectasis. Nevertheless, toilet bronchoscopy is recommended as a first-line treatment when significant mucus accumulation causes life-threating ventilatory obstruction and standard suctioning fails to promptly clear secretions. In the ICU, bronchoscopic procedures are associated with a 4% incidence of complications [11], most of them minor and transient [2]‌. However, no studies have specifically evaluated the complication rate of toilet bronchoscopy in ICU patients. The most common complications comprise severe refractory hypoxaemia [12], cardiac arrhythmias and ischaemia [13], haemodynamic instability and pulmonary haemorrhage (Box 122.2) [14].

* Enteral feeding or oral intake should be discontinued for 4 hours before the procedure.

INR, International normalized ratio; PTT, partial thromboplastin time, BUN, blood urea nitrogen.

Monitoring

A chest X-ray should be routinely performed prior to the procedure to identify areas of atelectasis. Strict monitoring is strongly advised during toilet bronchoscopy. Throughout the procedure, heart rate, oxygen saturation, ventilatory parameters, arterial pressure, and, in specific cases, intracranial pressure, and end-tidal carbon dioxide should be assessed.

Equipment

Bronchoscope

In intubated and mechanically-ventilated patients the insertion of the bronchoscope into the artificial airway drastically increases airflow resistance [12] and hinders ventilation. In order to prevent barotrauma and to allow adequate ventilation, it is suggested to use a bronchoscope with a diameter at least 2-mm smaller than the endotracheal tube’s internal diameter [15]. Toilet bronchoscopy is an invasive procedure and the use of a sterile bronchoscope is mandatory to avoid iatrogenic respiratory infections.

Additional equipment

Strict hand hygiene is essential prior to and after the procedure. The bronchoscopist should wear protective clothing (gloves, disposable apron, and protector visor) to minimize potential contamination with colonized respiratory secretions. A swivel adapter should be positioned at the proximal tip of the endotracheal tube to allow insertion of the bronchoscope and mechanical ventilation during toilet bronchoscopy. The outer surface of the bronchoscope should be lightly lubricated with water-soluble lubricant to allow easy passage through the artificial airway. Intrabronchial instillation of sterile saline solution, or mucolytics (10 or 20% acetylcysteine, dornase alfa, 2-mercaptoethane sulphonate), is commonly performed to aspirate inspissated secretions. Sterile saline and mucolitycs are also occasionally used to perform a broncho-alveolar lavage aimed at removing distal mucus plugs [6]‌. Nevertheless, to date, no studies are available to confirm the additional benefits associated with broncho-alveolar lavage. Finally, a sterile mucus trap may be connected to the working channel to collect and culture aspirated mucus.

Vacuum

It is recommended the level of vacuum be adjusted before performing toilet bronchoscopy to improve the efficacy of suctioning and minimize complications. No studies have comprehensively evaluated the efficacy and safety of toilet bronchoscopy at increasing vacuum levels. When using a 5.2-mm outer diameter bronchoscope the vacuum level is commonly set at –400 mmHg. Nevertheless, in patients with loose secretions, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), or those intubated with a 7-mm internal diameter endotracheal tube, the vacuum should be decreased to the lowest level that efficiently removes secretions to reduce risks of lungs collapse. Importantly, the primary aim of toilet bronchoscopy is aspiration of secretions; hence, suctioning when the bronchoscope is not close to secretions, or when all the mucus has already been aspirated should be avoided.

Setting the mechanical ventilator

Several ventilatory parameters should be adjusted to safely perform toilet bronchoscopy. However, no international consensus exists on how to set the mechanical ventilator during the procedure. First and foremost, given the significant risk for developing hypoxaemia, the inspiratory fraction of oxygen should be increased to 100%. Secondly, bronchoscopy is usually performed during either flow- or pressure-controlled modes of ventilation. The flow-controlled mode ensures the delivery of the set tidal volume, and the resulting pressure applied to the airway opening can rise to any value according to the impedance to inflation and the pressure limit alarm. Thus, prior to insertion of the bronchoscope the pressure limit alarm needs to be increased to allow for ventilation. During pressure-controlled ventilation minute ventilation can drastically decrease, unless the set inspiratory pressure is adjusted to overcome the bronchoscope-related airflow resistance. Finally, there is evidence from laboratory [15] and clinical studies [16] that the insertion of a bronchoscope into the artificial airway significantly increases the positive end-expiratory pressure (PEEP), because of the added resistance to passive exhalation and gas trapping. Nevertheless, during toilet bronchoscopy frequent aspirations could ultimately result in lung derecruitment, rather than significant gas trapping [17]. For these reasons the ventilatory mode should be set based on the patient’s underlying conditions and associated risks. In patients with significant intrinsic PEEP or at risk for barotrauma, pressure-controlled mode of ventilation should be preferred, whereas in patients with acute lung injury, ARDS, hypercapnic, or who require high levels of PEEP, volume-controlled mode could be a safer choice. Thirdly, the external PEEP should be markedly decreased during the procedure to at least 50% of the baseline values, or even less in patients with underlying bronchoconstriction, emphysema, and auto-PEEP. Finally, the ventilator should be allowed to trigger during suctioning to prevent lung derecruitment, thus flow- or pressure- trigger should be set accordingly.

Sedation, analgesia, and topical anaesthesia

Toilet bronchoscopy is an invasive procedure, which is highly uncomfortable for patients. The use of sedatives, analgesics and topical anaesthetics is mandatory to achieve favourable procedural condition, improve patient tolerance and reduce potential complications [18]. Commonly, in deeply sedated and intubated patients on mechanical ventilation toilet bronchoscopy can be performed by applying topical anaesthetics, administered as needed through the bronchoscope working channel. 1 or 2% lidocaine solution is the most commonly used anaesthetic. Care should be taken with the total administered dose in patients of advanced age, and with impaired liver function and cardiac conditions. In lightly sedated, mechanically-ventilated patients and those on spontaneous ventilation, systemic sedation, analgesia, and topical anaesthetics are recommended. Short-acting sedatives, i.e. midazolam and propofol achieve optimal sedation, anxiolysis, and amnesia, and are highly recommended for toilet bronchoscopy. Fentanyl is the preferred analgesic during toilet bronchoscopy due to its rapid onset of action, short half-life, and efficient suppression of cough. In specific cases, short-acting neuromuscular blocking agents can be used to optimize ventilation during the procedure and to prevent potential complications.

Toilet bronchoscopy during invasive ventilation

The bronchoscope is initially inserted into the artificial airway and secretions accumulated within its lumen are fully aspirated. When lobar atelectasis is detectable at the chest radiograph, the bronchoscope should first be advanced toward the secondary bronchus tributary of the lung consolidation, and mucus plugs fully removed. Next, all lobar bronchi should be comprehensively assessed and built up secretions removed. In patients with disseminated retention of airways secretions, a systematic approach should be undertaken in order to ensure full removal of airway secretions from all secondary bronchi. Follow-up chest radiograph is recommended to demonstrate resolution of the atelectasis.

Toilet bronchoscopy during non-invasive ventilation

Several patients who require non-invasive ventilation are often unable to efficiently clear respiratory secretions. In those patients toilet bronchoscopy may prevent respiratory deterioration and the need of endotracheal intubation. Studies have reported feasibility and safety of fibre optic bronchoscopy in critically-ill patients with acute lung injury [19] and COPD exacerbation [20]. Nevertheless, to date, no randomized controlled studies have been conducted to assess the clinical usefulness of toilet bronchoscopy in patients who require non-invasive ventilation. Topical anaesthesia of the nasopharynx and larynx with lidocaine should be performed prior the procedure. Systemic light sedation and/or analgesia should be considered on a case-by-case basis. It is highly recommended that the inspiratory fraction of oxygen be increased to 100%. Inspiratory and end-expiratory pressures should be adjusted to achieve optimal ventilation and oxygenation. During the procedure, the bronchoscope can be inserted through a T-adapter attached to a face mask (Fig. 122.3) or a specific connector placed in the plastic ring of a helmet and advanced into the airways via either a nasal or oral route.

Fig. 122.3 Toilet bronchoscopy during non-invasive ventilation. (a) Transnasally insertion of the flexible bronchoscope during non-invasive ventilation. (b) The T-adapter was attached to the face-mask for the insertion of flexible bronchoscope and its passage through the nose.

Fig. 122.3 Toilet bronchoscopy during non-invasive ventilation. (a) Transnasally insertion of the flexible bronchoscope during non-invasive ventilation. (b) The T-adapter was attached to the face-mask for the insertion of flexible bronchoscope and its passage through the nose.

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