Fiberoptic Bronchoscopy during Nasal Non-Invasive Ventilation in Acute Respiratory Failure

Background: Various methods have been described for safely performing fiberoptic bronchoscopy (FB) while applying non-invasive positive pressure ventilation (NIPPV) in patients with acute respiratory failure (ARF). Objectives: To evaluate the safety of a new method to perform FB in patients with ARF. Methods: Patients with ARF in whom FB was indicated were studied. The primary end-point was a mean drop in oxygen saturation (S a O 2 ) after the procedure. During nasal NIPPV, FB was performed via the mouth using a bite block sealed with an elastic glove finger allowing bronchoscope insertion. Results: Thirty-five patients were included in the final study (63 8 17 years, 74% men, P a O 2 /F i O 2 ratio 168 8 63). A total of 35 bronchoaspirates, 21 protected brushings, 11 bronchoalveolar lavages and 8 bronchial biopsies were done. The cardiorespiratory variables at the start and end of FB were: S a O 2 93 8 3 to 94 8 5%, heart rate 95 8 17 to 99 8 22 b.p.m. and respiratory rate 24 8 11 to 25 8 11 respirations/min. The lowest S a O 2 value reached during the procedure was 86 8 3% and the maximal ET CO 2 rise was 41 8 4 mm Hg. Leakage was ! 50 ml/s in 32 patients. The cliniReceived: December 15, 2009 Accepted after revision: March 2, 2010 Published online: April 27, 2010 Eusebi Chiner Pulmonology Section, University Hospital of Sant Joan d’Alacant Ctra. Alacant-València s/n ES–03550 Sant Joan d’Alacant (Spain) Fax +34 96 565 8750, E-Mail chiner_eus @ gva.es © 2010 S. Karger AG, Basel 0025–7931/10/0804–0321$26.00/0 Accessible online at: www.karger.com/res D ow nl oa de d by : 54 .1 91 .4 0. 80 9 /1 6/ 20 17 8 :1 3: 15 P M Chiner/Sancho-Chust/Llombart/Senent/ Camarasa/Signes-Costa Respiration 2010;80:321–326 322 Many of these patients have pulmonary infiltrates or retention of secretions which make it necessary to perform fiberoptic bronchoscopy (FB) [1, 2, 7] in order to reach an etiological diagnosis and thus implement the measures necessary to reduce the high mortality that exists in these patients. In cases of severe pneumonia, early microbiological diagnosis helps in selecting the right antibiotic and may improve the prognosis [8] . In addition, approximately 15% of patients with cancer develop ARF, and FB with bronchoalveolar lavage (BAL) is the basis of causal diagnosis [9] . Bronchoscopy is a widely performed procedure that is generally considered to be safe and effective. In recent years, its range of application has been greatly expanded. However, FB is not devoid of risks. Severe complications occurred in 0.637% and mortality was noted in 0.013% of patients [10] . The bronchoscope occupies approximately 10% of the normal airway and may cause the arterial oxygen pressure (P a O 2 ) to drop between 10 and 20 mm Hg during the procedure [9, 11] . This may cause serious respiratory complications or cardiac arrhythmias. For this reason, FB is contraindicated in non-intubated patients with hypoxemia (inspiratory oxygen fraction (F i O 2 ) 1 50%, necessary to maintain a P a O 2 of 75 mm Hg) [12] . In these patients, there have traditionally been two options: intubate in order to carry out FB with invasive mechanical ventilation (IMV) or not perform the procedure and apply empirical treatment with all the risks this implies. In recent years, FB has been done while simultaneously applying NIPPV in order to reduce the risks of FB in patients with ARF. Very few studies have been published: two methods of applying NIPPV have been described [13–16] as well as another method that makes use of continuous positive airway pressure (CPAP) [17] . We present the results of a new method whose main advantage is the simplicity of the procedure, which makes it easy to perform. Patients and Methods Study Subjects From November 2004 to November 2008, adult patients admitted to the Sant Joan d’Alacant University Hospital were studied. In order to be included in the study, the patients had to fulfill the following criteria: (a) They were admitted to the pulmonology ward or intensive care unit. (b) They had ARF, meeting 2 or more of the following criteria: (1) P a O 2 /F i O 2 ! 200; (2) respiratory rate (RR) 1 35 respirations/min, and (3) dyspnea at rest. (c) FB was indicated for diagnostic or therapeutic purposes according to any of the following criteria: (1) atelectasis; (2) infiltrates or pulmonary masses on chest X-ray; (3) retention of secretions, and (4) hemoptysis. Exclusion criteria were: (a) Inability to maintain S a O 2 6 90% despite NIPPV via the nasal route. (b) Intolerance to NIPPV. (c) Clinical indication for IMV, defined as one or more of the following: (1) need for cardiopulmonary resuscitation; (2) hemodynamic instability; (3) encephalopathy, and (4) coma. Study Design This is a prospective observational study designed to assess the safety of FB via the oral route by means of a sealed system and applying NIPPV via a nasal mask. The primary end-point was the evaluation of the reduction in pulse oximeter oxygen saturation (S a O 2 ) during FB. The secondary end-points were changes in RR, end-tidal CO 2 (ET CO 2 ) and heart rate (HR), the existence of complications and need for intubation and IMV after the procedure. The study was approved by the local ethics committee and all the patients gave their informed consent. Methods When FB was indicated, arterial blood gases (ABG) were obtained with the patient receiving conventional oxygen therapy via a Venturi-type mask, which gave the initial P a O 2 /F i O 2 ratio. Once this parameter had been determined and after obtaining the patient’s informed consent, NIPPV was started. This was done using a bilevel nasal positive pressure system (BiPAP; Respironics, Murrysville, Pa., USA) in the spontaneous/ cycled mode adjusting the inspiratory (IPAP) and expiratory positive airway pressure (EPAP) independently in order to achieve effective ventilation (expiratory tidal volume 6 10 ml/kg). In all cases, minimum IPAP and EPAP of 14 and 5 cm H 2 O, respectively, were considered. In order to ensure that the pressures administered remained steady during NIPPV, the remote control of the apparatus was used to monitor the expiratory tidal volume, leaks, IPAP and EPAP continuously by means of a digital system. These were adjusted during the procedure whenever necessary according to S a O 2 and ET CO 2 . The interface used was a nasal mask (ComfortClassic; Respironics), with a chin support connected to the head harness holding the mask in place. Supplementary oxygen therapy was delivered (between 5–15 l/min) via a cannula connected to the mask, and regulated to maintain S a O 2 6 90%. Initially, the patient underwent a 15to 20-min period of adaptation to the NIPPV. During this time, the S a O 2 was continuously monitored using a pulse oximeter (Nonin 8600 ; Nonin Medical, Minneapolis, Minn., USA) and the clinical tolerance evaluated. If the S a O 2 was found to be 6 90% and the patient adapted well to NIPPV, FB was started. Continuous non-invasive monitoring of ET CO 2 levels was performed with a Microstream capnograph (Oridion, Needham, Mass., USA). ET CO 2 was meaD ow nl oa de d by : 54 .1 91 .4 0. 80 9 /1 6/ 20 17 8 :1 3: 15 P M Fiberoptic Bronchoscopy during Nasal Non-Invasive Ventilation Respiration 2010;80:321–326 323 sured by a sampling line connected to the nasal mask. Microstream sampling lines blocked by secretions were replaced as needed. FB was performed via the oral route using a mouthpiece (MB142; Olympus, Tokyo, Japan). This was inserted in a latex glove, which was then tied with conventional suture through the external channel of the mouthpiece leaving one finger of the glove in the center. After tying the glove, excess material was cut away and with the help of a scalpel, a small incision ( 1–2 mm) was made at the tip of the glove finger, through which the bronchoscope was inserted ( fig. 1 ). The resulting device consisted of a mouthpiece, closed by an elastic membrane through which the bronchoscope was inserted and which acted as a retention valve for the pressure administered. A flexible videobronchoscope was used (EB250S; Fujinon; Saitama, Japan). For topical anesthesia of the pharynx, a 10% lidocaine solution was sprayed. For anesthesia of the larynx and vocal cords, a 2% lidocaine solution was instilled through the lumen of the bronchoscope. The bronchoaspirate was obtained by aspiration through the internal channel of the bronchoscope. Samples were sent for cytological and microbiological study. In patients in whom there was suspicion of an infectious etiology, a protected-specimen brush was used in the zone with the greatest radiological alteration. BAL was done in patients in whom there was a clinical indication. The tip of the bronchoscope was inserted into the orifice of a subsegmentary bronchus that showed infiltrates on chest Xray. Three aliquots of 50 ml of non-bacteriostatic saline serum were instilled at room temperature. Quantitative cultures with a number 1 10 5 , 1 10 3 and 1 10 4 colony-forming units/ml, respectively, for bronchoaspirate, protected-specimen brush and BAL were considered significant [15] . Bronchial biopsies were done when necessary if there was suspicion of bronchial neoplasia or alteration in the bronchial mucosa. Secretions were suctioned when necessary after instillation of saline or sodium-2-mercaptoethane sulfonate. During the procedure, S a O 2 , ET CO 2, HR and RR were continuously monitored. After FB, patients continued with NIPPV for 15 min, while still being monitored. Subsequently, conventional oxygen therapy was continued as before the procedure. ABG were collected 2 h after the FB. Any complications attributable to the procedure were recorded: e.g. sudden appearance of: (1) deterioration of ABG, (2) decreased level of consciousness or (3) cardiac arrhythmias, need for orotracheal intubation and IMV (time after FB and cause) and cause of death. Statistical Analysis Statistical analysis was done using a statistical package for Windows (SPSS, version 13; SPSS, Chicago, Ill., USA). Kolmogorov-Smirnov’s test was done to assess the normality of the distribution of all the quantitative variables. Respiratory parameters were compared using Student’s t test for paired data or the MannWhitney test. p ̂ 0.05 was considered significant.