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Pulmonary Complications during Acute SCI

Respiratory complications occur in 36-83% of patients with acute SCI, the exact nature of which is dependent upon the level of injury as this determines which respiratory muscles are affected due to loss of innervation. Impaired respiratory muscle function leads to complications such as improper bronchial secretion clearance, pneumonia, atelectasis, septicemia, pulmonary embolism, and reduced vital and inspiratory capacity (Warren et al. 2014). It has been suggested that the key to their prevention is intense secretion management (Claxton et al. 1998). Hygienic behaviours such as changing the patient’s body position to promote postural draining, performing manual assisted coughing or chest percussion, and clearing bronchial secretions are effective in reducing death from pulmonary complications (Mansel & Norman, 1990). Large volumes of mucus, or mucus harbouring inside the lung for extensive periods of time, encourage the growth of bacteria and subsequent development of pneumonia. In addition to pneumonia, atelectasis and respiratory failure are the most common pulmonary complications following acute SCI (Berlly & Shem, 2007), and often require mechanical ventilation to manage (Galeiras Vázquez et al. 2013). To confound this problem, mechanical ventilation puts patients at an increased risk for ventilator-assisted pneumonia, demonstrating how these complications can be difficult to control. Individuals with ventilator-assisted pneumonia have a death rate of 20-30% and an extended hospital stay (Call et al. 2011; Cook, 2000). Other conditions such as aspiration, acute lung injury, acute respiratory distress syndrome, and complications related to tracheostomy and intubation, such as tracheal stenosis or stomal cellulitis, also have negative respiratory implications but are less well studied.

Pulmonary Complications

Discussion

The main conclusion drawn from these studies is that respiratory complications are prevalent among patients with acute SCI, and the likelihood of their development depends on a number of factors related to the initial injury on admission. Overall, pneumonia is the most studied associated complication with a greater incidence in patients with a higher level of injury (Cotton et al. 2005; Fishburn et al. 1990), a more severe injury (Hassid et al. 2008; Huang & Ou, 2014), larger lesions (Aarabi et al. 2012), additional  fractures (Chen et al. 2013; Harrop et al. 2001), no return of deep tendon reflexes after one day (Lemons & Wagner, 1994), and who received surgical tracheostomy instead of percutaneous (Romero-Ganuza et al. 2011). With regard to tracheostomies, there is conflicting evidence regarding their contribution to respiratory complications. Some studies have found that patients who had tracheostomies experienced reduced respiratory complications compared to patients who did not have a tracheostomy (Leelapattana et al. 2012), whereas other studies reported the opposite (Harrop et al. 2004; Kornblith et al. 2014).

The development of respiratory complications is also dependent on several other factors including the completeness of the injury (Lemons & Wagner, 1994), the timing of the tracheostomy (Romero-Ganuza et al. 2011; Romero et al. 2009) and the cause of injury (Aarabi et al. 2012). Age may play a role in the development of complications (Aarabi et al. 2012), although this finding is not always supported (Lemons & Wagner, 1994). Likewise, some studies reported that receiving an early tracheostomy lowered the risk of problems (Kornblith et al. 2014; Romero-Ganuza et al. 2011; Romero et al. 2009), but other studies found it did not matter (Choi et al. 2013). There has been no disagreement that pulmonary complications cause a significant burden to the individual and also to the hospital system, as it increases time on ventilation, hospital stay and costs (Aarabi et al. 2012; Chen et al. 2013; Kornblith et al. 2014; Winslow et al. 2002). Furthermore, if complications cannot be managed initially, they may accumulate and put a patient at risk for more respiratory problems. For example, Huang and Ou (2014) found that the presence of respiratory failure led to a higher likelihood of developing pneumonia. It is therefore important that prophylactic measures be taken to prevent pulmonary complications, and that they are managed intensely should they arise.

Conclusion

There is level 3 evidence (from one case control, one case series and three observational studies; Hassid et al. 2008; Lemons and Wagner 1994; Huang and Ou 2014; Chen et al. 2013; Aarabi et al. 2012) that respiratory complications are associated with more severe injuries among acute SCI patients.

There is level 2 evidence (from one cohort study; Leelapattana et al. 2012) that acute SCI patients who have tracheostomies experience fewer respiratory complications than those who do not have tracheostomies. However, there is level 3 evidence (from one case control and one case series; Harrop et al. 2004; Kornblith et al. 2014) that tracheostomy in acute SCI patients is associated with increased respiratory complications and morbidity compared to patients without tracheostomy.

There is level 4 evidence (from four case series; Kornblith et al. 2014; Babu et al. 2013; Romero-Ganuza et al. 2011a; Romero et al. 2009) that early tracheostomy reduces the risk of pulmonary complications compared to late tracheostomy in acute SCI patients. However, there is level 4 evidence (from one case series; Choi et al. 2013) that the timing of tracheostomy does not influence the incidence of pulmonary complications in acute SCI patients. 

  • Respiratory complications are common among patients with more severe injuries during the acute phase post SCI.

    There is conflicting evidence regarding whether or not having a tracheostomy as well as the timing of tracheostomy influences the development of pulmonary complications during the acute phase post SCI.