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Tracheostomy tube (TT) is usually removed in a planned manner once the patient ceases to have the condition that necessitated the procedure. Accidental decannulation or extubation refers to inadvertent removal of tracheostomy tube out of the stoma. It could prove fatal in an otherwise stable patient. We review a variety of unexpected and often-overlooked causes of accidental decannulation with suggestions on preventive measures. We therefore present three cases of accidental decannulation of tracheostomy tubes in order to report our experiences in the management of the condition.
Accidental decannulation occurs both in hospitalized and patient on home care of their tracheostomy tubes. Reduction in neck circumference due to weight loss predisposes to accidental decannulation, which could be prevented by suturing the flange to the skin.
A range of unusual lethal circumstances involving tracheostomy have been documented in forensic autopsy reports and accidental decannulation is one of the identified potentially fatal mechanisms1. Incidence in open surgery tracheostomy ranged from 0 to 15%2,3 and reported mortality is less than 1%3. Although it is a relatively common occurrence in children and adult with altered sensorium2,4,5, especially during explosive coughs2when the collar tie is not properly secured. Weight changes in pregnancy and disease are not commonly reported predisposing factors. Similarly uncommon are missed-dislodgement of tracheostomy tube into the pretracheal space, and inadvertent decannulation due to fractured collar plate of an over used metallic tracheostomy tube.
A 35year-old nursing mother who presented with one-hour history of accidental removal of her tracheostomy tube which had been in place for over a year since she developed abductor paralysis post thyroidectomy. Patient had been on home care of tracheostomy tube and otherwise enjoying good health with seldom attendance at follow up clinics. She had the tracheostomy fixed in the first trimester of pregnancy and was in her third trimester when tracheostomy tie was last changed. She admits significant weight loss after delivery.
About the 5th month after delivery, she was trying to remove her long head cover (Kimar) across her head when she noticed that the tracheostomy tube had been dragged entirely out of the stoma. There was no immediate respiratory distress but patient was extremely anxious. She got to the A&E with a size 6.5 plain tracheostomy tube hanging on her neck; the collar tie was intact and well knotted at the flanges (figure 1). However, the tie appeared lax with the space between the neck and the string roomy enough to admit 3 to 4 fingers. Flexible fibre optic laryngoscopy demonstrated bilateral vocal cord paraesis with weak abduction movement. She was commenced on a formal decannulation process which was not tolerated, leading to subsequent insertion of another size 6.5 double lumen, portex tracheostomy tube.
A 47 year-old midwife who had had bilateral vocal cord palsy complicating a second thyroid surgery for recurrent goitre 11 years after the first thyroidectomy. The tracheostomy tube had fallen out of the stoma while taking her bath and she observed that the collar plate had fractured. She had a change to the current metallic tracheostomy tube 5years earlier and had since been on home care. Her follow up clinic had been irregular and as a result earlier complaints with the tube were unreported. At different times, she improvised a tough twine as a collar tie to manage earlier chip fractures of the collar plate; she also used adhesive tape to occlude the tracheostomy tube perhaps to improve her voice quality (Fig. 2). She presented to the hospital in apprehension even though her vital signs were essentially stable. A new metallic tracheostomy tube was reinserted with good outcome.
A 25 year-old suspected armed robber who was shot in the neck by the police patrol team presented with a bleeding neck wound and inability to speak and was in painful distress with moderate pallor. Wound exploration after resuscitation under general anaesthesia via a size 8.5-cuffed endotracheal tube (ETT), which was passed through a ragged rent at the upper 1st and 2nd trachea rings. There was also a compound comminuted fracture of the laryngeal skeleton with extensive damage to the extra-laryngeal muscles and exposure of the thyroid cartilage with an oesophageal tear. The external wound measured 10cm by 12cm with a tract communicating with the endolarynx. Emergency tracheotomy was done and the oesophageal tear was repaired over a size 20 Fr. NG-tube. Most of the fractured segments of the laryngeal skeleton still retained partial attachment to either the perichondrium or the pretracheal fascia. Wound was carefully debrided and thoroughly irrigated, fractured segments were manually reduced and held in position by minimal repair of the pre-trachea fascia using vicryl 3/0 suture. Surrounding viable muscles and skin were then mobilized in layers to cover the exposed cartilage as much as possible.
Post operatively the wound was complicated with sepsis and subsequent dehiscence. This led to a prolonged stay on nasogastric tube feeding with attendant weight loss. During a ward round, the tracheostomy flanges were observed to be overhanging the stoma and all attempts to reposition it were unsuccessful. CTscan showed otherwise adequate tracheobronchial air column with the tracheostomy tube in the pre-tracheal space; he had been breathing through the laryngo-cutaneous fistula tract and partly para-tubal rather than through the tracheostomy tube. As there was no demonstrable airflow through the tracheostomy tube; the tracheostomy tube was subsequently removed by the bed side with the patient awake. The neck wound later healed and the patient discharged in a stable condition.
Tracheostomy is commonly performed to relieve upper airway obstruction from congenital or acquired conditions. Common causes in our environment are obstructions due to benign or malignant tumors, iatrogenic injury to the recurrent laryngeal nerve during thyroidectomy with resultant vocal cord paralysis, neck trauma, laryngotracheal infections or foreign body impaction. Indication for tracheostomy in case 1 and 2 was vocal cord palsy complicating thyroidectomy; while gunshot injury to the neck was the indication in case 3.
In all cases of tracheostomy, the collar tie is usually done in such a way to admit a finger around the neck to prevent strangulation. However, any further reduction in neck circumference due to weight loss will make the collar tie excessively loose. This will result in undue mobility of the tracheostomy tube with attendant risk of complications ranging from migration of the tube, accidental decannulation, and vascular erosion. For the same reason, the tube flanges are some times sutured to the neck skin when accidental decannulation is anticipated6. Similar sequence of events explains the accident in case 1 and 3. Kapadian et al7 observed that tracheostomy accidents became less frequent, primarily due to the elimination of tracheostomy tube displacements by the use of adjustable-length tracheostomy tube. This design of tracheostomy tube is not available in our setting at the moment.
Physiological weight change is a prominent feature of pregnancy. It is occasioned by fat acquisition, water retention and hormonal changes due to the growing fetus and placenta8,9. It varies from one woman to another and it is affected by gravidity, parity and pre-pregnant body mass index8,9. On the average, a woman gains between 10 and 16kg in pregnancy10,11. The greatest gain occurs in the second trimester10,11 with a more rapid rate of gain occurring during the eighth and ninth months10,11. In a study of weight gain in pregnancy and weight loss after delivery, fifty (28%) of the women had returned to their prepregnant weight or less by the 6th-week postpartum visit8. The greatest amount of weight loss occurs in the first three months postpartum and then continues at a slow and steady rate until six months postpartum12. The tracheostomy in case 1 was last reviewed when the patient was in her third trimester of pregnancy when her neck circumference was possibly at its widest. Subsequent postpartum weight loss resulted in sagging of the collar tie, which was perhaps not noticed until the accidental decannulation occurred. (figure 1)
On the other hand, weight loss in injury and sepsis is due to utilization of fat, breakdown of hydrated lean tissue protein with increased nitrogen excretion and loss of water in excess of tissue fuel13. The degree of weight loss is roughly proportional to the severity of injury and may be as high as 400-900g per day13. Such an increase in calorie expenditure is unlikely to be met in the patient in case number 3 who had to be on nasogastric tube feeding for a long time as a result of gunshot injury that involved the aerodigestive tract with subsequent wound sepsis13. The resultant weight loss may account for the slack in the collar tie that ultimately led to the dislodgement of the tracheostomy tube into the pretracheal space as shown in figure 3a.
In-patients are not immune from dislodgement of the tracheostomy tube as in case 3. A high index of suspicion is required for early diagnosis and prompt correction and when in doubt, imaging will be of value. In case 3, the first alert to the doctor on round was the collar flange that was not properly sitting on the anterior neck skin. Orotracheal intubation and ventilation remain the first and safest approach of managing a lost tract from early procedural accidental decannulation3. Undetected accidental decannulation for a critical period of time was found to be the cause of death in the report of Roger et al1. In most practice, meticulous watch on tracheostomy patient is commonly concentrated on the immediate postoperative period when the patient is probably drowsy, critically ill or restless; while the guard is relaxed as patient becomes stable, up and about. Our experience (with case 3) is that of an intermediate complication of surgery, which occurred when the patient was assumed to be clinically stable.
There is no rigid rule for the durability and safe use of metallic tubes14, neither is there a standardized time for changing portex tracheostomy tube. However studies have recommended a change of plastic tracheostomy tube in 1 to 2months and metallic tubes in 6 months15,16. Metallic tracheostomy tubes are usually prescribed for long-term use, as they are known to be durable. Even though, its use may be limited by a number of factors, which include, factory errors, metal component of the alloy, tissue reaction, and corrosion by body fluid and secretions. The patient reported in case 2 had used the metallic tube for over 5 years and had managed previous fractures of the tube at various points without reporting to the hospital until the accidental decannulation occurred. Although, previous case reports of metallic tracheostomy fractures were not associated with fatality14 Okafor in Enugu, Nigeria reported a case of aspirated fractured metallic tracheostomy tube in a farmer who did not get to the tertiary hospital until 4 days later15. The incidence of accidental decannulation of tracheostomy tubes is not easily available, further compounded by the few number of autopsies in our environment because of paucity of consent by surviving relatives on account of cultural and religious beliefs18,19. Even where it is done, accurate evaluation of possible causes of death is made difficult by the routine removal of tracheostomy tube by nursing staff as part of the tidy up of bodies before movement to the morgue, thus making assessment of the ante-mortem tube position by the pathologist impossible1.
Accidental decannulation occurs both in hospitalized and patient on home care of their tracheostomy tubes. Reduction in neck circumference due to weight loss predisposes to accidental decannulation which could be prevented by suturing the flange to the skin.
Competing Interests: The authors have declared that no competing interests exist.
Grant support: None