Authors: Caixue Pan, Yao Chen, Yongfang Zhou
Categories: Case Reports, Airway pressure release ventilation, Case report, Cervical spinal cord injury, Respiratory support, Severe hypoxemic respiratory failure, Weaning
Source: Journal of Trauma Nursing
Cervical spinal cord injury can greatly affect pulmonary function, resulting in complications, including respiratory failure with prolonged mechanical ventilation, ultimately leading to increased mortality and high health care costs. Weaning from mechanical ventilation is particularly challenging in patients with complete high spinal cord injury.
We present the case of a 42-year-old man who suffered a complete cervical 5–6 spinal cord injury following a rollover motor vehicle crash and subsequently developed postoperative pneumonia and severe hypoxemic respiratory failure. He received a novel approach to fast-track respiratory care, including early and aggressive secretion clearance management, moderate pressure level of airway pressure release ventilation, timely transition to spontaneous mode, early tracheostomy and humane care, and high-flow oxygenation via tracheotomy after weaning off the ventilator. As a result, the patient experienced significant improvement in pulmonary function and was successfully liberated from the ventilator within a 2-week period.
This case highlights the potential effectiveness of fast-track respiratory care in promoting lung function restoration and expediting liberation from mechanical ventilation in patients with severe hypoxemic respiratory failure following a complete cervical spinal cord injury. However, further research is warranted to validate these findings and expand our understanding in this area.
Keywords: Airway pressure release ventilation, Case report, Cervical spinal cord injury, Respiratory support, Severe hypoxemic respiratory failure, Weaning
Spinal cord injury (SCI) has become increasingly prevalent, predominantly resulting from motor vehicle crashes, falls, and acts of violence (Leathem et al., 2021). Respiratory complications, such as atelectasis, pneumonia, and respiratory failure, are frequently encountered among patients with cervical SCI. These complications contribute significantly to ventilator dependence and represent the primary cause of morbidity and mortality during both the acute and long-term phases (Satkunendrarajah et al., 2022; Tollefsen & Fondenes, 2012).
Weaning from mechanical ventilation poses considerable challenges for patients with high complete SCIs, and prolonged weaning periods are associated with increased respiratory complications, mortality, and substantial health care costs, particularly for those presenting with severe hypoxemic respiratory failure (Füssenich et al., 2018). The management of airway and respiratory function is paramount in facilitating lung function restoration, preventing morbidity, and reducing mortality (Kornblith et al., 2013).
To date, no intervention strategy has demonstrated efficacy in promoting accelerated pulmonary rehabilitation and rapid weaning for patients with severe hypoxemic respiratory failure following complete cervical SCIs. In this case report, we present the experience of implementing a novel approach (details listed in Table 1) to fast-track respiratory care, promote pulmonary function recovery, and facilitate early liberation from the ventilator in a patient complicated with pneumonia and severe hypoxemic respiratory failure secondary to a complete cervical 5–6 SCI. This case report adheres to the CARE guidelines (Gagnier et al., 2014).
This is the case of a 42-year-old man who was in a rollover motor vehicle crash. The patient immediately complained of neck and shoulder pain and limited neck mobility. The patient was transported to the closest hospital, where the initial workup revealed a cervical 5–6 SCI. After wound debridement at the local hospital, approximately 5 hr later, he was transferred to West China Hospital of Sichuan University, an academic medical center located in Chengdu City, Sichuan Province, China. The treatment course is outlined in Figures 1 and 2.
Figure 1. Treatment course and lung images. (A) CT scan shows patches, bands, and consolidation in the dorsal area of the lungs at admission. (B) Bronchoscopy shows cicatricial occlusion of the right lower lobe lateral segment. (C) Chest x-ray displays a few exudative lesions in the lungs on the first day after the operation. (D) CT scan shows mediastinal and subcutaneous emphysema and patches and consolidation on the bilateral lungs on the third day after the operation. (E) CT scan shows mediastinal and subcutaneous emphysema significantly improved on the fifth day after the operation. (F) CT scan shows few bands and consolidation in the dorsal area of lungs on the 20th day after the operation. A/C-VCV = assist/control-volume control ventilation; APRV = airway pressure release ventilation; Bid = twice a day; MAP = mean arterial pressure; PaCO
2= arterial partial pressure of carbon dioxide; PaO2= arterial partial pressure of oxygen; PSV = positive support ventilation; Qd = once a day; Qid = four times a day; Tid = three times a day.
Figure 2. Case report timeline.
Upon admission, his respiratory rate was 18/min, heart rate 75 beats/min, blood pressure 109/63 mmHg, and Glasgow Coma Score 15. He presented with neck pain and dyskinesia and had Grade 0 muscle strength in his limbs, with the absence of all motor and sensory functions, including sacral segments S4–S5, characterized by an American Spinal Injury Association Impairment Scale Grade A injury (Roberts et al., 2017). A computerized tomography scan revealed a fracture at the cervical 5–6 level, as well as patches, bands, and consolidation in the dorsal region of both lungs. The patient was diagnosed with tetraplegia (Frankel A) due to a cervical SCI, as well as respiratory failure and bilateral pulmonary contusion with infection (Figure 1A). As a result, the patient underwent anterior cervical 5/6 discectomy. However, after the operation, he developed severe hypoxemic respiratory failure and was transferred to the surgical intensive care unit. His heart rate was 104 beats/min, blood pressure was 118/59 mmHg, with a norepinephrine maintenance dose of 0.1 μg/kg/min, and temperature was 36.7 °C. Under mechanical ventilation with assistance/controlled-volume-controlled ventilation mode, with a respiratory rate of 12 breaths/min, tidal volume of 7.4-ml/kg predicted body weight, positive end-expiratory pressure of 8 cmH2O, and inspired oxygen fraction of 100%, the arterial oxygen partial pressure/inspired oxygen fraction (PaO2/FiO2) ratio was 53.5 mmHg, and the carbon dioxide partial pressure was 39.7 mmHg. A bronchoscopy was performed at the bedside, revealing significant viscous mucus plugs in the airways bilaterally, along with cicatricial occlusion of the right lower lobe lateral segment (Figure 1B). Following secretion clearance, recruitment maneuvers, and adjustment of positive end-expiratory pressure to 12 cmH2O, the PaO2/FiO2 ratio increased to 144.2 mmHg.
Throughout his early phase of treatment, the patient experienced frequent restlessness and was administered remifentanil for analgesia, with a maintenance dose of 2.1 μg/kg/hr. He also received moderate sedation (Richmond Agitation Sedation Scale [RASS] score −3) through continuous infusions of propofol (0.6 mg/kg/hr) and midazolam (0.04 mg/kg/hr). Sputum culture revealed the presence of Staphylococcus aureus, and piperacillin was administered for antiinfection purposes. Chest x-ray displayed a few exudative lesions in the lungs (Figure 1C). Despite postural drainage, chest vibration four times a day, and daily bronchoscopy, the patient could not clear sputum, leading to a decreased pulse oxygen saturation. Consequently, the patient required bronchoscopy twice a day.
On the second day following the operation, midazolam was discontinued. In the presence of persistent hypoxia, the assistance/controlled-volume-controlled ventilation mode was transitioned to the airway pressure release ventilation mode. The initial settings were a release rate of 14 frequencies/min, high pressure of 24 cmH2O, low pressure of 5 cmH2O, time of low pressure of 0.6 s, and inspired oxygen fraction of 40%. After 6 hr of airway pressure release ventilation, oxygenation was significantly improved with a PaO2/FiO2 ratio of 257. However, the following morning, palpation of the right lateral chest revealed crepitus, and the computerized tomography scan showed mediastinal and subcutaneous emphysema (Figure 1D). As a result, the airway pressure release ventilation mode was switched to the pressure support ventilation mode without surgical drainage, and the settings were pressure support 10 cmH2O, positive end-expiratory pressure 8 cmH2O, and inspired oxygen fraction 50%. Arterial blood gas analysis revealed the arterial oxygen partial pressure of 115.9 mmHg and the carbon dioxide oxygen partial pressure of 40.8 mmHg.
On the fourth day, the patient's blood pressure became relatively stable, prompting the replacement of norepinephrine with metaraminol. The maintenance dosage of metaraminol (0.25–1 μg/kg/min) was adjusted to maintain the target mean arterial pressure between 85 and 90 mmHg. On the fifth day, the patient displayed restlessness, leading to the administration of dexmedetomidine at a continuous infusion rate of 0.32 μg/kg/hr to achieve the desired sedation level (RASS score −2). The computerized tomography scan showed minimal subcutaneous emphysema and pneumomediastinum, as well as scattered nodules, patchy shadows, and consolidation in both lungs, along with small amounts of pleural effusion on both sides (Figure 1E). The PaO2/FiO2 ratio was 244.2 under pressure support ventilation.
On the seventh day, a tracheostomy was performed. The following day, the patient was successfully weaned off the ventilator through high-flow oxygen therapy (flow 45 L/min, inspired oxygen fraction 30%) via tracheotomy. Manual hyperinflation therapy was administered twice a day to promote lung expansion, resulting in further improvement in oxygenation (PaO2/FiO2 ratio 336.75). As the amount and consistency of sputum improved over the next 12 days, the intensity of airway secretion clearance measures was gradually reduced. On the 25th day, the patient was transferred to the rehabilitation ward with significantly improved pulmonary function (Figure 1F). Two months later, he was successfully discharged, and his limb dysfunction had improved, with bilateral shoulder shrug muscle strength and left upper limb muscle strength at Grade 3.
Cervical SCI greatly alters pulmonary function, such as respiratory muscle weakness, ventilation function compromise, ineffective cough, limited possibilities for changing position, bronchial hyperresponsiveness, and increased bronchial mucus secretion mediated by the parasympathetic nervous system. These factors contribute to poor secretion clearance, atelectasis, pulmonary infections, and respiratory failure, leading to prolonged mechanical ventilation, ventilator dependence, and increased morbidity and mortality. It has been reported that the average duration of the weaning process in cervical and high thoracic SCI patients is 37 days (Reyes et al., 2020; Satkunendrarajah et al., 2022).
We established a novel approach to fast-track respiratory care (Table 1), which included early and aggressive management of secretion clearance, moderate pressure level in airway pressure release ventilation, timely transition to spontaneous mode, early tracheostomy and humane care, and high-flow oxygenation via tracheotomy after weaning off the ventilator.
In this case, the patient suffered a complete cervical 5–6 SCI due to a motor vehicle crash and developed postoperative pneumonia and severe hypoxemic respiratory failure. With the implementation of our approach, the patient's pulmonary function improved, and he was successfully weaned off the ventilator within 2 weeks. This case demonstrates that this systemic approach to fast-track respiratory care was crucial in maintaining airway patency, restoring lung function, and achieving rapid liberation from the ventilator in cervical SCI patients with severe hypoxemia.
Secretion clearance measures include postural drainage, chest vibration, mechanical insufflation–exsufflation or manually assisted cough, spontaneous cough training, endotracheal tube suctioning, and bronchoscopy. The selection and frequency of these measures should be determined based on the amount of sputum and the efficacy of secretion clearance. In this case, a patient who suffered a complete cervical 5–6 SCI and experienced pneumonia and severe hypoxemic respiratory failure, postural drainage, chest vibration, and bronchoscopy were performed twice a day during the early phase. As the risk of secretion retention decreased, the intensity of these measures was gradually reduced. Despite intensive secretion clearance efforts in the acute phase, the patient's oxygenation did not improve further, even with repeated recruitment maneuvers and higher positive end-expiratory pressure.
Airway pressure release ventilation was defined as the application of continuous positive airway pressure with brief releases to allow spontaneous breathing during the high-pressure phase (Jain et al., 2016). Animal experiments and our previous clinical trial findings have shown that airway pressure release ventilation can facilitate the opening of collapsed lung areas, preserve spontaneous breathing, decrease intrathoracic pressure, improve systemic venous return, mitigate the cardiovascular depressant effects of positive pressure, enhance respiratory mechanics and oxygenation, and expedite successful weaning (Lescroart et al., 2022; Zhou et al., 2017). However, to date, the effectiveness and safety of airway pressure release ventilation in cervical SCI patients with severe hypoxemia have not been reported.
Considering that cervical SCI is associated with lower sympathetic activity and commonly impaired hemodynamics, this patient was subjected to a moderate pressure support level of airway pressure release ventilation. Consistent with previous findings, oxygenation significantly improved without hemodynamic compromise (Lescroart et al., 2022; Zhou et al., 2017). Unfortunately, the patient developed mediastinal and subcutaneous emphysema the following day. Airway pressure release ventilation was switched to pressure support ventilation mode without surgical drainage, and barotrauma gradually resolved over the next 2 days. This occurrence might be explained by the fact that during airway pressure release ventilation with its prolonged high-pressure phase and brief release phase, gas was more easily taken in than expelled through the severely stenosed airway of the right lower lobe lateral segment, leading to excessive gas accumulation and subsequent barotrauma. This finding suggests that a moderate pressure level of airway pressure release ventilation is a safe and more effective mechanical ventilation strategy for cervical SCI patients with severe hypoxemic respiratory failure. However, the utilization of airway pressure release ventilation should be cautious or may not be considered in cases of severe airway stenosis or obstruction.
When his hemodynamics stabilized on the fourth postoperative day, metaraminol was administered as a substitute for norepinephrine to ensure adequate tissue perfusion (Partida et al., 2016). Early tracheostomy facilitates oral care and secretion clearance, promoting early liberation from mechanical ventilation and reducing the duration of stay in the intensive care unit (Foran et al., 2022). Thus, this patient underwent tracheostomy as early as the seventh postoperative day when deemed ready for weaning.
Additionally, in this case, we prioritized appropriate analgesia and sedation to ensure comfort, improve sleep quality, and cuff deflation to enhance communication and reduce the risk of posttraumatic stress disorder (Li & Feng, 2020). Moreover, cervical SCI exacerbates ventilator-induced diaphragm dysfunction (Smuder et al., 2016). As soon as the patient could initiate breaths spontaneously, he was transitioned to pressure support ventilation mode to facilitate respiratory muscle training. The pressure support level was set at a minimum to maintain the respiratory rate and tidal volume within the target ranges, thereby preserving diaphragm contractile function and facilitating earlier weaning from mechanical ventilation (Yi et al., 2021).
High-flow oxygen therapy offers several physiological benefits, such as maintaining inspired oxygen fraction concentration without dilution, providing gentle, positive end-expiratory pressure, washing out the dead space of the upper airway, and reducing airway resistance. High-flow oxygen therapy administered through a tracheostomy has been shown to improve airway humidification, comfort, and oxygenation and reduce sputum viscosity, lung infection, and respiratory effort while increasing alveolar ventilation and facilitating liberation from prolonged mechanical ventilation (Mitaka et al., 2018; Yang et al., 2019). In accordance with the previous findings, this patient received high-flow oxygen therapy via a tracheotomy after weaning off the ventilator; his secretion clearance and pulmonary function were further improved, leading to rapid, successful weaning (Mitaka et al., 2018).
This case report provides a valuable and practical approach to fast-track respiratory care of patients with severe hypoxemic respiratory failure secondary to a complete cervical SCI. However, there are two limitations to consider. First, the case report lacks long-term follow-up data, and second, our experience in fast-track respiratory care is still limited to generalization. Therefore, further studies are necessary to explore and deepen our understanding in this area.
In this case report, we present a novel approach to fast-track respiratory care for a postoperative patient with a complete cervical 5–6 SCI complicated by severe hypoxemic respiratory failure. The findings from this case suggest that early and aggressive management of secretion clearance, combined with moderate airway pressure release ventilation, can effectively improve oxygenation and promote pulmonary rehabilitation without compromising hemodynamics. Additionally, early tracheotomy following cervical surgery, early transition to spontaneous breathing mode to preserve diaphragm function, and high-flow oxygenation via tracheotomy after weaning can expedite liberation from mechanical ventilation in patients with severe hypoxemic respiratory failure secondary to a complete cervical SCI. This case report provides a clinical foundation for implementing fast-track respiratory care in similar patients, but further research is needed. We confirm that the patient provided informed consent to present this case.
We thank all the physicians, nurses, and respiratory therapists at the Departments of Respiratory Care and Critical Care Medicine, West China Hospital of Sichuan University, for their dedication to patient care and their support of this study.
Caixue Pan, Email: 1316640445@qq.com.
Yao Chen, Email: yoyochen19851001@qq.com.
Yongfang Zhou, Email: zyfmg@163.com.