“Feel of the reservoir bag” … A dying skill in midst of sophisticated equipment! Kinking of endotracheal tube during posterior fossa surgery

I read with interest the article on Severe intraoperative brain bulge due to endotracheal tube obstruction by a thick mucous plug by Singhal et al.[1] I congratulate the authors for averting a near-fatal situation using timely change of the blocked endotracheal tube. There was a rise in EtCO2 levels and gradually increasing airway pressures in the child being ventilated with the help of a ventilator.

"Feel of the reservoir bag" … A dying skill in midst of sophisticated equipment! DOI: 10.4103/0019-5049.63627 Sir, I read with interest the article on Severe intraoperative brain bulge due to endotracheal tube obstruction by a thick mucous plug by Singhal et al. [1] I congratulate the authors for averting a near-fatal situation using timely change of the blocked endotracheal tube. There was a rise in EtCO 2 levels and gradually increasing airway pressures in the child being ventilated with the help of a ventilator.
I think the problem could have been detected earlier had they been ventilating the lungs manually. The hands of an experienced anaesthetist are trained to instantaneously detect a change in the compliance of the reservoir bag provided the "initial feel" of the bag is used as a base line. Significant time must have elapsed before the EtCO 2 rose to 60 mm Hg. Unfortunately, with the advent of sophisticated equipment and monitors; much less emphasis is placed nowadays on the 'feel' of the bag.
The steps of management of the presented case could have been better sequenced. When the airway pressures and the EtCO 2 levels were rising, a quick check by manual ventilation and feel of compliance followed by ruling out endotracheal tube obstruction (by suctioning) or circuit obstruction and bronchospasm before giving supplemental doses of opioids and muscle relaxants and performing an arterial blood gas analysis, could have avoided the severe intraoperative brain bulge that was seen in the presented case. Sir, The airway obstruction during intraoperative period may occur from various causes. It could be difficult to make a diagnosis and secure free airway following airway obstruction due to kinking of endotracheal tube (ETT) in a prone patient with open cranium. We would like to report a case of unexpected ETT kinking in an 8-yr-old male child weighing 22-kg during posterior fossa surgery in prone position. Anaesthesia was induced with intravenous morphine, propofol and vecuronium. The patient's trachea was intubated orally with a cuffed polyvinyl chloride (PVC) ETT (Portex blue-line, single use) of 5.0 mm. The tube was inserted into the trachea without any resistance and secured at 15 cm at the teeth. Proper ETT position was confirmed by chest auscultation and sustained capnography. Anaesthesia was maintained with propofol infusion and 66% nitrous oxide in oxygen. Patient's lungs were ventilated with volume control ventilation through Datex Ohmeda ventilator using closed circuit. The surgery was started after turning the patient in prone position with flexion of atlanto-axial joint. Toward the end of the surgery (approximately 2.5 h after intubation), the airway pressure began to rise from 24 to 32 cm of H 2 O. Capnography showed normal end-tidal CO 2 but upward sloping pattern. The oxygen saturation was maintained at ≥97%. There was no sign of bronchospasm on auscultation. No obvious change -in lung compliance was detected on manual ventilation. The nasopharyngeal temperature was 36.4°c at this time. The circuit was checked systematically for kinks, obstructions or leaks but none was found. A 10 F flexible suction catheter was then passed down the lumen of the ETT to exclude partial obstruction. The catheter could not pass down the tube after 6 cm. A palpating finger inside the oral cavity revealed an intraoral kink of the ETT.
Effective mechanical ventilation and reduction in airway pressure (form 32 to 28 cm of H 2 O) could be achieved after manual straightening of the kink and repositioning of the head. The surgery was completed without further difficulty. The direct laryngoscopy after turning the patient supine, revealed a partial kink at the oropharynx portion of the ETT. Anaesthesia was Letters to Editor www.ijaweb.org reversed and the tracheal extubation proceeded after full recovery of consciousness. Inspection of ETT after it was removed showed partial kinking just beyond the attachment of cuff inflation tube [ Figure 1].
The ETT kink during posterior fossa surgery might result from overbending of the softening tube due to oral temperature and neck flexion. [1] Campoy et al. demonstrated higher incidence of kinking of ETT during maxima flexion of atlanto-axial joint. [2] The smaller size tubes may be more prone for airway obstruction. It could be difficult to carry out reintubation in such an awful situation when the patient was prone and in pins with surgery in process. Manual straightening of the tube may be helpful to relive kinking of ETT. In a recent report the placement of Berman intubating airway [3] was found to be helpful in these situations. Emphasis should also be laid on the proper positioning of the head and neck prior to surgery. The use of reinforced, nonkinking ETT may be considered in high-risk patients.

Sir,
A 30-yr-old female presented with a gradually progressive swelling on the right side of the neck for 7 yrs along with tingling, numbness and pain in the right upper limb for 1 yr. She had a 6 cm × 5 cm smooth, firm, globular, nontender mass in the right supraclavicular region without any local rise of temperature, venous engorgement or skin change. Her airway examination was normal. On examination she was found to have sensory loss in the medial side of the arm, forearm and the medial half of the palm and dullness and diminished breath sound in the right apical lung area.
Routine blood investigations, Electrocardiogram (ECG) and ultrasound of the abdomen were within normal limits. Chest X-ray revealed an ill-defined mass in the right supraclavicular region. Magnetic resonance imaging (MRI) of the thoracic region showed a well-defined 8.26 cm × 6.36 cm × 4.30 cm mass in right para-vertebral region extending from C7 to T2 vertebral levels along with intraspinal extension and cord compression. Cervical intervertebral disc and airway anatomy were normal. A provisional diagnosis of neurogenic tumor was made and the case was posted for excision under general anaesthesia (GA).
After connecting the pulse oximeter, ECG electrodes and blood pressure cuff, we established a 14G intravenous line and premedicated the patient with intravenous (IV) fentanyl 2 µg/kg and ondansetron 0.1 mg/kg. GA was induced with IV propofol 2 mg/ kg and succinyl choline 1.5 mg/kg IV and the trachea was intubated with an appropriate sized flexometallic tube. We cannulated the left internal jugular and radial artery after induction of GA. Anaesthesia was maintained with isoflurane and injection of vecuronium and fentanyl.
After 45 min of stable vitals of the patient, we noticed a sudden drop of blood pressure, tachycardia