Points to ponder for ‘Preventing unrecognised oesophageal intubation consensus guideline’

Sir,

The comprehensive guidelines of “Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies” by Chrimes et al.[1] are published in early view Online Version of Record before inclusion in an issue of ‘Anesthesia’ journal, released on August 17, 2022. Esteemed members of various airway societies of the world came together to form guidelines so as to prevent serious consequences of an unrecognised oesophageal intubation. Inability to detect sustained exhaled carbon dioxide is suggested to be a strong indicator of oesophageal intubation, while the conventional monitoring with stethoscope is considered as highly inadequate and outdated. Unrecognised oesophageal intubation continues to be one of the common causes of profound hypoxaemia and death in patients undergoing anaesthesia or critical care management.

“Prevention and early identification of oesophageal intubation,” instead of “Preventing unrecognised oesophageal intubation,” can be considered more appropriate, as the objective is not only to prevent oesophageal intubation but also to identify it early, if it has occurred.

The clinical skills of visualising the endotracheal tube passing across the vocal cords, understanding the feel of the bag with intermittent positive pressure ventilation (IPPV), a good chest rise-and-fall, 5 points auscultation, presence of end tidal carbon dioxide (ETCO₂) waveform, flow volume loop, airway pressure waveform, and peripheral oxygen saturation (SpO₂) are being taught to anaesthesia postgraduate novices for confirmation of endotracheal tube placement and for the prevention and early identification of oesophageal placement of the endotracheal tube.[2] Oesophageal detector device has also been used to detect oesophageal intubation in emergency situations. Time used for confirming the presence of sustained exhaled (ETCO₂) over at least 7 breaths (as recommended by the consensus guideline), can be used simultaneously to confirm the previously mentioned conventional clinical cues. Technical issues with CO₂ monitoring at crucial times can be a catastrophic limitation. Airway occlusion must be actively excluded in case of a flat capnograph. Ventilating the stomach for 7 breaths before recognising an oesophageal intubation can cause regurgitation, aspiration and set in hypoxia.[2] Thus, all the parameters should be routinely assessed rather than relying on a single parameter. While flexible endoscopy and ultrasound visualisation can directly confirm the oesophageal tube placement, their use may not be feasible due to non-availability of equipment or expertise or an assistant for all episodes of airway management.[3] There is a practice recommended for endotracheal tube placement confirmation—”when in doubt, take it out.” If we do not practise the clinical skill of auscultation for air entry, it is likely that the skill would become redundant, making it unreliable when essential to use. Continuous and trending information from a monitoring system is extremely useful under anaesthesia but interpretation of these data by trained professionals with respect to clinical situations is of paramount importance to decide appropriate response.

Anticipation is one of the most important factors for early detection of unintended oesophageal intubation. What the mind does not think, the eyes do not see. The primary airway managers must be able to anticipate the possibility of oesophageal intubation and tracheal tube dislodgment, especially in following cases such as when there is difficult airway or multiple attempts at intubation, for patients posted for emergency or airway sharing surgery, orofacial and airway trauma requiring intubation, or in neonates with tracheo-oesophageal fistula. This can also happen in patients who require intubation or resuscitation in the catheterisation lab, post-anaesthesia care unit, non-operating room anaesthesia location, intensive care unit, or in surgical positions other than supine, during patient transfer or movement or when intubation is done by junior residents.[4]

Human factors like anticipation, cognition, communication, and decision-making are well-known to affect the task performance and subsequent patient outcome in airway management by anaesthesiologists.[5]

Thus, to expand application and compliance of the recently published guidelines, there should be anticipation of oesophageal intubation. Practice of confirmation of tracheal intubation or prevention and early identification of oesophageal intubation must be followed using conventional techniques along with presence of sustained exhaled CO₂.

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