Minimally Invasive Cardiac Surgery (MICS) usually requires lung isolation for proper exposure of the surgical field. Isolation of the lungs is particularly applicable in patients undergoing cardiac, esophageal and other thoracic surgeries. Traditionally the usage of Double Lumen Tube (DLT) is considered the gold standard for lung isolation. But with the increasing complexities of surgeries in geriatric, fragile patients and with difficult airway anatomy, bronchial blockers have been found to be useful.
A 74-year-old male patient was admitted with complaints of chest discomfort 1 month ago. A coronary angiogram was done on 28/3/2022 which showed triple vessel disease and he was advised to undergo MICS involving LIMA to LAD and SVG to OM2. The patient also had a h/osystemic hypertension for 2 years, type 2 diabetes mellitus for 20 years and dyslipidemia.
The patient was prepared for MICS under general anesthesia with invasive standard lines. One lung ventilation was planned as lung deflation is needed for the MICS and is generally done by using a double-lumen endobronchial tube (DLT) (a). The placement of a DLT may be more challenging in certain patients because it has a larger diameter than that of a Single-Lumen Endotracheal Tube (SLT).
A preoperative assessment of the airway was done and there was an adequate mouth opening of more than 3 finger breadths. Neck extension and flexion had no restriction. Other routine investigations were done and the patient was ready to undergo surgery.
On the day of surgery, the patient was received in the preoperative area and a 16G I.V cannula was placed in the right forearm along with a 3F right radial arterial line. The patient was shifted to the OT and all the standard ASA monitors were connected. Adequate preoxygenation with 100% oxygen was given and inducing 300mcg fentanyl and 5 mg of midazolam was started. For muscle relaxation, succinylcholine 100mg was given. After induction, we were able to perform mask ventilation. We tried to insert the 37F double-lumen tube using a 4 size McCoy laryngoscope blade. But we could only visualise the epiglottis and some posterior parts of arytenoids. The best visualisation was Cormack Lehane grade 2b. An attempt was then made to visualise by using external laryngeal manipulation. The neck was repositioned and we tried inserting the double-lumen tube multiple times. DLT could not be passed because of malalignment of DLT and airway curvature of the patient and intubation was not successful.
Mask ventilation was then done with 100% oxygen and it was planned to secure the airway by using an Arndt bronchial blocker(b) under the guidance of a Fiberoptic Bronchoscope(FOB). We managed to secure the airway with an 8mm endotracheal tube under bougie guidance. Then ports of the bronchial blocker were connected to the endotracheal tube. Both the bronchial blocker and the fibreoptic bronchoscope were inserted through their corresponding ports such that the distal end of the FOB had passed inside the loop snare of the bronchial blocker. The loop snare (c) was then tightened near the tip of the FOB. The bronchial blocker and the snared FOB were then passed inside the endotracheal tube. We were able to visualise the carina and the FOB was advanced into the left main bronchus. This allowed us to guide the bronchial blocker pass beyond the FOB and the bronchial cuff was inflated under visualisation. The FOB was then withdrawn and the port was closed. The loop snare was withdrawn and we checked for ventilation of the right lung and it was adequate. Intraoperatively, surgery was uneventful. Both the lungs were post-electively ventilated operatively with the cuff deflated for 10 hours, after which it was extubated. The patient was stable.
Lung isolation techniques in patients with either a suspected or unanticipated difficult airways are more challenging. Using a DLT in unanticipated difficult airways is nearly impossible as they are more rigid and larger compared to the conventional endotracheal tube. Thus bronchial blockers are the safest means of achieving one lung ventilation after the ETT has been properly placed. Arndt bronchial blockers are thin, rigid catheters with an outer diameter ranging from 5–9 Fr with an inner lumen and a distal cuff at the tip. Inflating the cuff prevents distal airflow, thus isolating the desired lung. The Arndt blocker is a thin balloon-tipped catheter and contains an inner lumen through which a wire with a loop snare is passed through it till it reaches the distal end. A FOB is used as a stylet to guide the wire loop into the desired bronchus.
Bronchial blocker is preferred to DLT due to the following reasons:
- In anticipated difficult airway (Mallampati grading 3 or 4, bucked upper incisors, receding mandible, restricted neck movements)
- Patients requiring post operative ventilation as there is no need for tube exchange
- In nasal airway access or in tracheostomy tubes
- Minor airway injuries
(a) DOUBLE LUMEN TUBE (DLT)
(b) BRONCHIAL BLOCKER (c) LOOP SNARE WITH FOB
One lung ventilation in patients with challenging unanticipated difficult airway anatomy requires the prior arrangement of a difficult airway trolley with a Fibreoptic bronchoscope on standby. Though double lumen tubes are most commonly used in achieving one lung ventilation, bronchial blockers provide a safe, effective and efficient option to DLT in securing unanticipated difficult airways, provided that it is possible to secure conventional ETT.
(1) Minimally Invasive Cardiovascular Surgery, Methodist Debakey Cardiovasc J, 2016 Jan-Mar; 12(1): 4–9.
(2) Bronchial Blocker Use in the Difficult Airway Patient Requiring Lung Isolation ; Anesthesia & Analgesia: December 2018
(3) Comparison of left double lumen tube and y-shaped and double-ended bronchial blocker for one lung ventilation in thoracic surgery – a randomised controlled clinical trial; BMC Anesthesiol. 2022; 22: 92.
(4) Bronchial blocker versus left double-lumen endotracheal tube in video-assisted thoracoscopic surgery: a randomized-controlled trial examining time and quality of lung deflation; Randomized control trial; Can J Anaesth; 2016.
(5) Bronchial Blocker Versus Left Double-Lumen Endotracheal Tube for One – Lung Ventilation in Right Video-Assisted Thoracoscopic Surgery; Randomized control trial; J Cardiothorac Vascanesth. 2018.