Acute respiratory distress syndrome: A case report
Ramudu1*, Shiny2
1Nurse Educator, Kauvery Hospital, Chennai, Tamilnadu, India
2Incharge Nurse, Kauvery Hospital, Chennai, Tamilnadu, India
*Correspondence: Tel: +91 97908 61662; Email: nursingdirector.kch@kauveryhospital.com
Abstract
Acute respiratory distress syndrome (ARDS) is a life-threatening condition characterized by severe hypoxemia due to pulmonary gas exchange failure and was first recognized in 1960s. Since its first description, it has undergone intensive research in the past few decades to understand its pathogenesis and therapies. Despite this, the recommended therapies to decrease mortality in ARDS remain limited and include low-tidal volume mechanical ventilation, prone ventilation and recently, the ECMO rescue therapy in extreme cases.
Keywords: Acute respiratory distress syndrome; Extracorporeal membrane oxygenation (ECMO)
Background
Acute respiratory distress syndrome (ARDS) is an acute life-threatening inflammatory lung injury manifested by hypoxia and stiff lungs due to increased pulmonary vascular permeability and almost always requiring mechanical ventilation support. ARDS represents an acute response to diverse provoking trigger factors and etiologies, resulting bilateral lung opacities on radiography and hypoxemia.
The Large observational study to Understand the Global impact of Severe Acute respiratory FailurE (LUNG-SAFE study) conducted as a multicentre, prospective, observational, 4-week inception cohort study reported that hospital mortality was 34.9% for patients with mild ARDS, 40% for those with moderate ARDS and 46.1% for those with severe ARDS. However, it remains unclear how much of the reported mortality in ARDS can be attributed to ARDS as opposed to underlying comorbidities, such as cancer and immunosuppression, the associated non-pulmonary organ dysfunction (cardiovascular insufficiency as in septic shock, liver dysfunction and renal failure) and/or the older age of patients with the condition. For example, a follow-up analysis of the LUNG-SAFE study determined that 21% of patients with ARDS in the study were immunocompromised, and hospital mortality was much higher in these patients than in non-immunocompromised patients.
Common risk factors for ARDS
| Direct | Indirect |
| Pneumonia | Non-pulmonary sepsis |
| Aspiration of gastric content | Major trauma |
| Inhalation injury | Pancreatitis |
| Pulmonary contusion | Severe burns |
| Pulmonary vasculitis | Non-cardiogenic shock |
| Drowning | TRALI (Transfusion-associated lung injury |
Case Presentation
A 45-year-old man with no prior comorbidities presented to Kauvery Hospital, emergency with fever and respiratory distress.
CT chest was done outside revealing bilateral consolidation. A clinical diagnosis of CAP/ARDS was made and patient shifted to ICU for further management.
On clinical assessment
| Temperature | Pulse | Respiration | Blood pressure | SPO2 |
| 98.4°F | 112 b/min | 32 b/min | 150/90 mmHg | 96% |
On physical examination patient was conscious, oriented, afebrile and tachycardic.
Management
He was initially managed with High Flow Nasal Cannula (HFNC), steroids, antibiotics, and DVT prophylaxis. His initial blood culture was sterile; flu panel, and Covid RT-PCR were negative. His general condition kept worsening and he got intubated electively on 2nd day and managed as per ARDS protocol along with prone ventilation. He developed a new onset fever and hypotension and hence polymyxin was continued. Hypotension resolved and his respiratory failure improved gradually over the next few days. He was extubated on 5th day and put on pre-emptive NIV. However, in view of fatigue, he got reintubated on 6th day. After a session of prone ventilation, his respiratory failure improved and tracheostomy was performed on 9th day. In view of weaning difficulty due to critical illness related polyneuropathy. He was gradually weaned off the ventilator and switched over to HFNC and then finally to thermovent. His tracheostomy tube was decannulated and oxygen supplementation provided via nasal prongs. He became hemodynamically stable, requiring resting oxygen of 1 L via nasal prongs, maintaining SPO2 97%. He was advised discharge with domicillary oxygen supplementation, and follow up after 3 weeks
Drug Chart
| S.No | Drug name | Dosage | Frequency | Route |
| 1 | T. Voritek | 200 mg | BD | Oral |
| 2 | T. Pantop | 40 mg | OD | Oral |
| 3 | Syp. Lactulose | 15 ml | BD | Oral |
| 4 | Syp. Grilinctus | 5 ml | BD | Oral |
Nursing care
- Manage nutrition
- Treating the underlying cause or injury
- Improve oxygenation with mechanical ventilation
- Suction oral cavity
- Give antibiotics
- Deep venous thrombosis prophylaxis
- Stress ulcer prophylaxis
- Observe for barotrauma
- Monitor blood chemistry and fluid levels
Prone ventilation
Prone ventilation showed improvement in the level of oxygenation and thus improved the outcome in patients with ARDS having severe hypoxia. This effect is due to the reduction in the trans-pulmonary pressure gradient making the patient prone, which helps in recruiting the collapsed areas of the lung without causing a significant increase in the airway pressures. Prone ventilation was found to be more effective in obese patients with ARDS than in non-obese patients.
Fluid-conservative therapy
In ARDS patients, due to increased alveolar vascular permeability, there is presence of alveolar oedema, which may get worsened as a consequence of fluid overload. The conservative approach of fluid management in ARDS has been proven to be beneficial in reducing ventilator days but doesn’t improve survival
Neuromuscular blockade
In spontaneously breathing patients with acute lung injury, it is possible that elevated transpulmonary pressures may exacerbate the degree of lung injury, thereby raising the question of whether intubation and ventilation with lower tidal volumes and reduced transpulmonary pressure might be beneficial1
Glucocorticoids
Methylprednisolone was among the first therapies tested in trials for preventing acute lung injury, intuitively appealing for its anti-inflammatory properties. Up to one-fifth of patients with ARDS receive systemic steroids, although their efficacy for attenuating lung injury remains unclear. Although some have reported a positive effect of steroids on survival, a multicentre trial of methylprednisolone versus placebo for persistent moderate to severe ARDS observed no survival benefit (7-28 days duration). Steroids accelerated resolution of respiratory failure and circulatory shock but also increased risk of neuromuscular weakness; patients initiating steroids >14 days after ARDS onset experienced increased mortality.
Inhaled pulmonary vasodilators
Inhaled nitric oxide and prostaglandin achieve selective vasodilation of the pulmonary circulation, improving ventilation-perfusion matching and, transiently, oxygenation in patients with ARDS. However, a benefit in patient-centred outcomes such as mortality has not been demonstrated. Pulmonary vasodilation could benefit patients with ARDS in whom associated acute cor pulmonale (right heart failure) is contributing to circulatory failure.
Discussion
In the clinical setting, increased recognition of ARDS in all regions of the world is important to better identify patients earlier in their clinical course so that supportive care with lung-protective ventilation and a conservative fluid approach can be implemented. Prognostic (or) predictive enrichment approaches that include biological and clinical variables in randomized trials may improve the chances of identifying responsive subsets of patients with ARDS. Some have questioned whether the syndromic definition of ARDS will continue to be useful given its lack of specificity, overlap with other distinct syndromes (that is, ARDS mimics) and the relentless failure of pharmacotherapeutics in this condition; however, there is not yet a consensus within the field on a suitable alternative approach.
Conclusion
There has been considerable research on ARDS in the past decade and better understanding of its pathogenesis. Despite this, the effective therapeutic measures to decrease mortality in ARDS seem to be low-tidal volume mechanical ventilation, prone ventilation for severe ARDS cases; and in life-threatening cases not responding to the conventional therapies, ECMO rescue technology serves as a bridge to recovery.
References
- Wang Y, et al. China Critical Care Sepsis Trial (CCCST) Workgroup. The Association Between Etiologies and Mortality in Acute Respiratory Distress Syndrome: A Multicenter Observational Cohort Study. Front Med (Lausanne). 2021.
- ARDS Definition Task Force, et al. ARDS Definition Task Force. Acute respiratory distress syndrome: The Berlin Definition. JAMA. 2012;307:2526-33.
- Wu C, et al. Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China. JAMA Intern Med. 2020;180(7):934-43.
Ms. Ramudu
Nurse Educator
