Cuffed endotracheal tubes are used for airway management in the operating room, emergency room, and intensive care unit. Anaesthetist and intensivists are aware that right main stem intubation may precipitate left-sided pulmonary atelectasis.¹ Inadvertent right main bronchus intubation can also cause paradoxical collapse of a portion of the right upper lobe.² There had been reports of right upper lobe collapse occurring after an uneventful endotracheal intubation.³ There had also been reports of right middle lobe collapse occurring, in isolation or in combination with a right upper lobe collapse, after an uneventful endotracheal intubation. Right upper lobe consolidation as a complication of endotracheal intubation has not been reported. We wish to report such a complication occurring in a young man who had an uneventful endotracheal intubation where he was thought to have had a right middle collapse and subsequently reported to have right upper lobe consolidation. The radiological features of right middle lobe collapse and right upper lobe consolidation and ways to diagnose them are discussed.

CASE REPORT

A 28 year old Caucasian underwent a Bankart’s repair of the left shoulder under general anaesthetic for a recurrent dislocation of the shoulder. He was fit and healthy non-smoker with no premorbid medical conditions (American Society of Anaesthesiologists (ASA) Grade 1). He had an uncomplicated endotracheal intubation and his electrocardiogram (ECG), blood pressure, SaO₂, ETCO₂, and oxygen inspiration were satisfactory throughout the operative period. The operative procedure was uneventful. Following extubation he was tachycardic and SaO₂ was 82% in the recovery room. Clinically there was reduced air entry over the apex and the middle of the right chest with good air entry in the lung base. He was resuscitated immediately and his SaO₂ improved to 95% (60% oxygen inhalation). ECG was normal and an x ray of the chest (fig 1) revealed shadowing in the right lung, which was thought to be right middle lobe collapse. Postoperatively he was treated with intravenous antibiotics, humidified oxygen, and chest physiotherapy. He was discharged home after 5 days of treatment. At 2 weeks follow up he had no chest problems and a chest radiograph showed complete expansion of the lung (fig 2). The radiologist reported his chest radiographs as right upper lobe consolidation (fig 1).

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Figure 1

 Anteroposterior radiograph showing right upper lobe consolidation. Reproduced with permission.

Figure 2

 Radiograph showing the cleared consolidation. Reproduced with permission.

DISCUSSION

Right bronchial airway obstruction is an infrequent complication of endotracheal intubation. Following emergency resuscitation procedures, it is more common than generally acknowledged.⁴ The upper lobe bronchus on the right side arises as an offshoot from the right main bronchus, whereas the left upper lobe bronchus arises further away from the carina as a bifurcation of the main trunk. In adults, the right main bronchus is only 2 cms and shorter. The right upper lobe bronchus can also arise from the lower end of the trachea. Therefore, occlusion of the upper lobe opening occurs when the right lobe bronchus is inadvertently intubated.⁵

Complete obstruction of the left main stem bronchus produces rapid atelectasis of the lung.⁵ Collapse of the right upper lobe is a rarely reported form of lobar atelectasis in the intubated patient. This usually follows inadvertent intubation of the right main bronchus. Seto et al observed that main stem intubation does not cause immediate collapse of the left lung, right lung preferential ventilation does not preclude right upper lobe collapse, and right upper lobe collapse can occur very rapidly after inadvertent intubation of the right main stem bronchus.²

Numerous mechanisms have been hypothesised: anatomical considerations of the right upper lobe bronchus, Bernoulli-type mechanism, compression of the upper lobe from hyperinflation of the lower lobes, and resorption atelectasis are the various factors leading to the right upper lobe collapse following intubation.^2,3 Halpern et al had reported the aetiology as multifactorial. This complication can occur at any time following an eventful or uneventful intubation.³

In our patient, the chest radiographs taken in the recovery room showed homogenous opacity in the right middle zone and the right heart border could not be seen. A diagnosis of right middle lobe collapse was made. Seto et al had reported right middle lobe collapse, either alone or in combination with right upper lobe collapse, occurring as a complication of inadvertent right bronchus intubation.²

It was a surprise when the radiologist reported the radiographs as right upper lobe consolidation. There has been no report of patients developing acute right upper lobe consolidation following an endotracheal intubation. In right middle lobe collapse the horizontal fissure and lower half of the oblique fissure move towards one another. In right upper lobe consolidation, the consolidation is confined by the horizontal fissure inferiorly and the upper half of the oblique fissure posteriorly. This can be best seen in the lateral projection. The signs of right middle lobe collapse are subtle in frontal projection and hence the difficulty in differentiating between right upper lobe consolidation and right middle lobe collapse.

In our patient the ventilation was uneventful throughout the operative procedure. One probable explanation was that there might have been a mucous plug obstructing the right upper lobe bronchus causing the consolidation and then clearing subsequently with treatment. Another possible reason was that the endotracheal tube might have displaced when transferring the patient from the operating table to the bed. This could lead to the endotracheal tube migrating into the right main bronchus thereby causing a collapse of the right upper lobe and then the patient subsequently developing an acute consolidation. If there is doubt in the differentiating between a collapse and a consolidation on an anteroposterior view of a chest radiograph, obtaining a lateral view would help in diagnosis for the reasons described earlier.

Anaesthetists, intensivists, and the emergency physicians need to be aware of right upper lobe consolidation occurring as complication of endotracheal intubation and the difficulty in the radiographic diagnosis of such a complication.