Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 647-648

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 647-648

Letter to Editor

Tracheal tube kinking during craniotomy in supine position after application of fish hook retractors

Surya Kumar Dube, Girija Prasad Rath, Nidhi Gupta, Navdeep Sokhal

Department of Neuroanaesthesiology, All India Institute of Medical Sciences, New Delhi, India
Correspondence Address: Girija Prasad Rath, Department of Neuroanaesthesiology, All India Institute of Medical Sciences, New Delhi, India, girijarath@yahoo.co.in

Date of Submission: 13-Apr-2011
Date of Decision: 14-Apr-2011
Date of Acceptance: 14-Apr-2011

Code Number: ni11199

PMID: 21891962

DOI: 10.4103/0028-3886.84366

Sir,

Several causes have been implicated for intraoperative airway obstruction in the context of tracheal tube kinking. We encountered yet another cause in a patient undergoing craniotomy in supine position.

A 27-year-old female with a frontal lobe tumor was scheduled for craniotomy under anesthesia. All the routine labs were within normal limits. Her past history and systemic examination were unremarkable. In the operation theater, she was connected to the routine monitors like pulse oximeter, electrocardiography (ECG), and non-invasive blood pressure. After securing an intravenous (IV) access, fentanyl 2 μg/kg was given. Anesthesia was induced with propofol 1 μg/kg. Rocuronium 1 mg/kg was given to facilitate endotracheal intubation with a 7.5-mm cuffed polyvinyl chloride (PVC) tracheal tube. Position of the tracheal tube was confirmed by a sustained capnography, and air entry on chest auscultation was equal on both the sides. After a right subclavian vein catheterization and left radial artery cannulation, the patient's head was rested on a horseshoe head-holder. Anesthesia was maintained with isoflurane in nitrous oxide and oxygen (2:1 ratio) along with intermittent boluses of rocuronium and fentanyl. At the time of dural incision, a sudden increase in peak airway pressure from a baseline value of 13-60 mmHg along with a progressive rise in end-tidal carbon dioxide (EtCO ₂ ) value and an upward sloping of EtCO ₂ curve was noticed. There were no signs of inadequate anesthetic depth or bronchospasm. Obstruction in the breathing circuit and inadvertent activation of oxygen flush was ruled out. There was no evidence of external kinking in the tracheal tube; in order to check the patency, a suction catheter was inserted which could not advance beyond 7-8 cm. On careful inspection below the surgical drape, an acute flexion of the patient's neck was observed and an intraoral kinking of the tracheal tube was suspected. Surgery was stopped for a brief period, neck was straightened manually. This maneuver reduced the increased peak airway pressure to 19 mmHg. Two minutes later, the same episode was repeated with an acute flexion of neck, following which the surgical site was observed. It was seen that two Fish hook retractors [Figure - 1] were applied to the skin flap from the Mayo stand in order to get a better surgical exposure. After the retractors were removed, the airway pressure became normal. Rest of the surgical period was uneventful at the end of which the trachea was extubated after reversal of residual neuromuscular blockade. The tracheal tube was found to be kinked [Figure - 2].

Increased airway pressure in the breathing system has been a major cause of anesthesia-related morbidities. Obstruction to airway, coughing or straining by the patient, activation of the oxygen flush during inspiratory phase, occlusion or obstruction of the expiratory limb of the breathing circuit are some of the causes implicated. ^[1] Kinking of tracheal tube is a frequent cause of airway obstruction. It is a known fact during surgery in position other than supine. It can occur with change in head position when the neck is flexed or due to overbending of a softened tracheal tube by oropharyngeal temperature, albeit, after several hours of intubation. ^[2] In our patient, intraoral kinking of the tracheal tube occurred in supine position after an hour of anesthesia. Spiral embedded tracheal tubes are less prone for kinking than PVC tracheal tubes. However, their routine use during supine craniotomy with head in neutral position is debatable. Nevertheless, maximal flexion of the atlanto-axial joint has been associated with a higher incidence of kinking. ^[3] In this case, the tracheal tube was kinked by application of Fish hook retractors in the anterior part of the skin flap that led to an acute flexion of neck. Probably, the head fixation by a three-pin head-holder could have prevented such a problem. In our center, supratentorial craniotomies are commonly performed by resting patient's head on a horseshoe head-holder. However, increased airway pressure, which has a propensity to intraoperative brain bulge, has never been encountered. Hence, we suggest avoidance of Fish hook retractors' application in patients undergoing craniotomy on a horseshoe head-rest. In this scenario, the use of flexometallic tracheal tubes, even if the patient placed supine, is not overemphasized.

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