An unusual case of cardiac tamponade presenting to the emergency department is reported in a patient with sternal wire disruption after a pectus excavatum repair two years previously. The complication, although rare may have potentially life threatening sequelae and therefore consideration of sternal wire disruption in all patients presenting with chest pain after a previous sternotomy should be made.
- sternal wire disruption
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A 24 year old man presented to the emergency department with a sudden exacerbation of central chest pain. He had undergone a pectus excavatum surgical repair two years previously and first became aware of pain three weeks before presentation while holidaying abroad. Upon return his general practitioner requested a chest radiograph, which confirmed fracture and displacement of part of the sternotomy wire. A cardiothoracic outpatient clinic was requested.
During this period the patient who was previously well complained of ongoing central sharp chest pain, radiating intermittently to his left shoulder and exacerbated by deep inspiration, coughing, and movement. There was no associated history of collapse haemoptysis, or calf pain. On the day of presentation the pain had become severe.
On examination he was alert and in considerable discomfort. His pulse was 81, blood pressure 145/65, respiratory rate 25, and oxygen saturations 100% on 4 l/min. Chest examination revealed a prominent sternotomy scar but was otherwise unremarkable. Abdominal, neurological, and limb examinations were similarly unremarkable.
An initial ECG showed sinus rhythm with a rate of 80, normal axis and some T wave flattening in leads 3 and Avf.
Attempted cannulation at this time was accompanied by a momentary loss of responsiveness and a decrease of systolic blood pressure to 75 mm Hg, which recovered with head tilt and 250 ml of crystalloid. A repeat ECG was unchanged.
A portable AP chest radiograph (fig 1) confirmed fracture and displacement of part of the left segment of the sternotomy wire with a lateral film (fig 2) indicating the degree of displacement.
He was referred to the cardiothoracic surgeons and an ECG was performed by the cardiologists showing a significant pericardial effusion 2.4 cm posteriorly, 3.6 cm inferiorly, and some evidence of early tamponade of the right atrium. Computed tomography of the chest confirmed pericardial puncture by the sternotomy wire (fig 3) and after a second hypotensive episode the patient was taken to theatre for an urgent thoracotomy.
It was only at this stage, some five hours after presentation that his ECG was noted to have evolved to show ST elevation in the inferolateral leads with an appearance consistent with pericarditis.
The patient went on to make a complete recovery.
Cardiac tamponade is a comparatively uncommon presentation to the emergency department, and is usually associated with penetrating trauma. Classic diagnostic teaching1 refers to “Beck’s triad” with hypotension, muffled heart sounds, and an increase in jugular venous pressure.
It should be acknowledged that while Beck’s triad is widely published and classically described, it is arguably a weak tool in the diagnosis of cardiac tamponade. Few clinicians, for example, would open a chest on the basis of muffled heart sounds as a discriminator.
Often the only clue to cardiac tamponade is a scenario in which pulseless electrical activity exists in the absence of hypovolaemia or a tension pneumothorax. This warrants an urgent pericardiocentesis. It was noted that this patient exhibited two short lived episodes of hypotension.
While radiological anomalies of sternotomy wires in dehisced sternotomy wounds are a well recognised entity,2 fracture of the wire with subsequent cardiac tamponade in a healthy patient is extremely rare.
In one case series of 19 patients with dehisced sternotomy wounds 89% (17) of patients revealed sternal wire radiological abnormalities with displacement in 16 (84%), rotation in 10 (53%), and disruption in 4 (21%).
The potential sequelae of pericardial puncture from the patients own fractured sternotomy wire is self evident. However, it should be noted that healthcare professionals may also be at risk with a reported case of a nurse in the USA sustaining a penetrating injury to her hand during cardiopulmonary resuscitation in a patient with a sternotomy wire from previous cardiac surgery.3 The nurse survived but faced the turmoil of viral immunological tests.
In conclusion, sternotomy wire migration is an uncommon occurrence but should it occur the consequences may be potentially fatal.
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