Anticipating, Preventing, and Treating Complications in Patients With Limited Pulmonary Reserve
The article entitled “Bronchoscopy safety in patients with chronic obstructive lung disease (COPD)” by Bellinger et al2 is an important one. They prospectively looked at 258 patients over 12 months who underwent bronchoscopy under moderate sedation as outpatients. Sixty-seven (44%) had COPD, with 6 (9%) having mild, 29 (42%) having moderate, 27 (41%) having severe, and 5 (8%) having very severe disease. Thirteen percent of the COPD patients had minor complications and 5% had severe complications. The severe and very severe COPD patients had significantly more complications compared with the patients without COPD. This study is prospective and well performed. The COPD patients were on inhalers, but the authors did not check whether each patient’s treatment was optimum before the bronchoscopy. This is also a single-center study. Identification of at-risk patient populations for bronchoscopy allows one to anticipate and prevent or reduce procedural complications in high-risk patients. This study helps define those patients at greatest risk for procedural complications.
In this article, patients with severe and very severe COPD, defined as those with forced vital capacity in 1 second (FEV1) <50% (severe COPD) and <30% (very severe COPD), experienced the most procedural complications. Understanding of medications and management techniques that can decrease procedural risk or utilization of bronchoscopy techniques for rapid intervention of procedure-related complications is critical for optimal patient management. This includes choice of sedation, interface for oxygen administration during and after the procedure, pharmacological interventions to prevent laryngospasm, monitoring and treatment of bronchospasm, rapid control of procedure-related bleeding, and identification and treatment of procedure-related pneumothorax.
Interventions shown to reduce bronchoscopy-related risk and treat procedural complications have been described. Sedation during bronchoscopy can precipitate hypoxic and hypercapnic respiratory failure. Ideal sedatives have rapid onset and short duration and allow rapid recovery.3 Hypoxemia is a common occurrence during bronchoscopy. Heated high flow utilizing a high-flow nasal canula high flow nasal canula at 60 L/min and FiO2 0.5 was shown to result in higher PaO2 and SpO2 and lower heart rates compared with those in patients managed with either the Venturi Mask or high flow nasal canula at lower flow rates.4 Pharmacological prevention of laryngospasm has been reported with both Magnesium (15 mg/kg) administered IV, topical lidocaine applied to the larynx before airway manipulation, and regional nerve block techniques.5,6 Rankin et al7 reported that pretreatment with intravenous aminophylline before bronchoscopy prevented significant bronchospasm in patients with mild asthma. Routine administration of inhaled bronchodilators before flexible bronchoscopy has been recommended in patients with asthma.8 However, preprocedural bronchodilator treatment in COPD patients did not prevent a decline in postprocedural FEV1. An important observation in this study was that patients with higher GOLD stage classification experienced more significant decline in the postbronchoscopy FEV1 and thus warrant close observation before and after the procedure.9 Interventions for bleeding after bronchoscopy included positioning the patient such that the bleeding lung is in the dependent position; wedging the bronchoscope in the segment/subsegment that is bleeding and installing iced saline can facilitate homeostasis; instilling thrombin (5000 U dissolved in saline) or instilling lidocaine/epinephrine or saline/epinephrine (1:1000 epinephrine) mixture can induce local vasoconstriction and facilitate homeostasis; and instilling Factor VII and tranexamic acid through the bronchoscope has also been carried out for postprocedural bleeding complications.