Moving on from ‘No Trace = Wrong Place’ for the exclusion of oesophageal intubation

It is a pleasure to write an editorial for this edition of the Indian Journal of Anaesthesia. The edition includes diverse papers on airway management: a comparison of intermediate-flow nasal oxygen versus high-flow humidified nasal oxygen for pre-oxygenation[1], a comparison of conventional versus nasopharyngeal bougie technique for nasotracheal intubation,[2] and a case report of awake tracheal intubation in a patient with cervical diffuse idiopathic skeletal hyperostosis.[3] What is common to all the clinical settings of these articles is that they end with a patient who has undergone tracheal intubation and the ultimate goal is the placement of a tube in the trachea. Nevertheless, the topic of this editorial is how we should act to confirm that tracheal intubation has been successfully achieved and critically to exclude oesophageal intubation.

Recently, ‘No Trace = Wrong Place’ has been highlighted as insufficient for the prevention of recognition of oesophageal intubation and also has caused confusion. Unfortunately, in the years since the launch of the ‘No Trace = Wrong Place’ campaign, instances of unrecognised oesophageal intubation continue to be reported, which have resulted in patient mortality.

In the United Kingdom, at an inquest, coroners can issue Reports for the Prevention of Future Deaths if they consider the inquest findings are of generalisable importance or highlight matters needing widespread remediation. In the past few years, multiple Reports for the Prevention of Death sent to the Royal College of Anaesthetists have focussed on unrecognised oesophageal intubation.[4] These various cases include one case of unrecognised oesophageal intubation where adequate confirmation of the tracheal tube with capnography had not occurred,[5] and another where a non-flat capnograph had been misinterpreted as indicating a correctly placed tube.[6] The literature also highlights cases where a tracheal tube in the wrong place has been associated with a trace,[7,8] or conversely, where a correctly placed tube resulted in the absence of a trace.[6,9,10] The seventh National Audit Project (NAP7) of the Royal College of Anaesthetists, which studied perioperative cardiac arrest, included an examination of complications of the airway and respiratory systems during anaesthesia leading to perioperative cardiac arrest. NAP7 highlighted six cases of unrecognised oesophageal intubation in total, three of which led to cardiac arrest.[11] Incorrect interpretation of the capnograph occurred in several of these cases, and NAP7’s recommendations included that clinicians who manage the airway should be aware of recently published guidance designed to prevent unrecognised oesophageal intubation. There is an ongoing problem of harm from unrecognised oesophageal intubation, and ‘No Trace = Wrong Place’ both fail to capture all cases of oesophageal intubation and have the potential to cause confusion. It is time to replace it.

Instead, it has recently been announced that ‘sustained, exhaled carbon dioxide’ will replace ‘No Trace = Wrong Place’. On 26 August 2025, the President of the Royal College of Anaesthetists, Dr Claire Shannon, wrote to members to confirm that ‘No Trace = Wrong Place’ has been retired by the College. This is in line with the 2022 Project for the Universal Management of Airway (PUMA) guidelines on preventing oesophageal intubation.[12,13] The College website also highlights this change.[14] The PUMA guidelines are widely internationally endorsed, not only by the Royal College of Anaesthetists but also by the UK Difficult Airway Society and the All India Difficult Airways Association.[13]

The criteria for sustained, exhaled carbon dioxide (CO₂) outlined by the PUMA guidelines are fourfold:

1. The CO₂ level rises during expiration and falls during inspiration,

2. A consistent or increasing amplitude over seven breaths,

3. A peak amplitude >1 kPa (7.5 mmHg) above baseline, and

4. A reading that is clinically appropriate. For instance, a trace may be attenuated, but in certain clinical contexts, this may be appropriate, for example, during cardiac arrest or a very leaky uncuffed tracheal tube. A trace should not be attenuated in a normal clinical setting.

The first major advantage of looking for sustained, exhaled CO₂ is that it is more specific than ‘No Trace = Wrong Place’. If the criteria are followed, it should prevent instances of unrecognised oesophageal intubation in which the capnography trace is not absent but rather is non-sustained or simply abnormal.[6] It addresses instances where the trace is attenuated and pushes for clinical correlation of this.[15] Second, it avoids the confusion which has latterly been associated with the ‘No Trace = Wrong Place’ phrase.

Prompting the anaesthetist to look for sustained exhaled CO₂ immediately is vital to exclude oesophageal intubation and is the best indicator that the lungs are being ventilated. Of note, exhaled CO₂ may be observed briefly during oesophageal intubation when CO₂ is present in the stomach from previous mask ventilation or ingestion of carbonated drinks, but it will not be sustained. Also notable is that there are numerous causes of a capnograph trace that does not meet the criteria for sustained exhaled CO₂, many of which may be trivial and easily detected, but oesophageal intubation is arguably unique because it will, if not detected, rapidly cause avoidable brain damage or death. It is for this reason that its exclusion is so heavily emphasised.

Previously, clinicians have looked for chest rise, tube misting, and perhaps chest auscultation; however, these are unreliable, with misting occurring in approximately 80% of oesophageal intubations.[12,15] Meta-analysis has demonstrated that clinical checks have too high a false positive rate and therefore cannot exclude oesophageal intubation. Hansel et al. reported that tube misting has the highest false positive rate, followed by auscultation, and that chest rise has insufficient evidence to assess.[16] In the situation of an airway crisis, it is inevitable that chest auscultation is unreliable and the literature is littered with reports of ‘breath sounds’ being heard and chest rise seen in cases of clear oesophageal intubation. The oft-quoted check of ‘chest rise, tube misting and then checking the capnograph’ can easily lead to anchoring bias and wrong conclusions.[17] The first check should be of capnography, and seeking sustained exhaled CO₂. Auscultation, along with other measures such as airway pressure, retains a role in seeking to exclude bronchial intubation, but not in detection of oesophageal intubation, when capnography is available.

The presence of sustained, exhaled CO₂ after attempted tracheal intubation is not a panacea. The absence of sustained exhaled CO₂ does not diagnose oesophageal intubation but does indicate the lungs are not being ventilated. This demands action, first to exclude oesophageal intubation, which can kill in minutes, and then to exclude other causes, at the same time making efforts to re-establish lung ventilation. However, it is currently the best method by which oesophageal intubation can be excluded, and it is superior to ‘No Trace = Wrong Place’, which it now should replace. Such a move is an important step towards eradicating the scourge of iatrogenic harm and deaths caused by unrecognised oesophageal intubation.

Presentation at conferences/CMEs and abstract publication

None.

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Disclosure of use of artificial intelligence (AI)-assistive or generative tools

AI tools or large language models have not been used in the preparation of this manuscript.

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No content from this manuscript is copyrighted.

Author contributions

RW: First draft and revision of drafts. TMC: Original idea, original guidance and revision of drafts.

Supplementary material:

None

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.