Nursing Care Considerations of Sepsis-Induced ARDS

This article highlights sepsis early recognition and prevention to reduce the risk of developing sepsis-induced ARDS while emphasising pathophysiology, early recognition, and early intervention for both conditions.

Introduction

Sepsis, a life-threatening condition caused by a dysregulated immune response to infection, is a preventable global health crisis (Singer et al. 2016). A report in 2020 indicated that around 48.9 million people were affected by sepsis, of which 11 million deaths secondary to sepsis account for 20% of mortality globally (WHO 2024). One of the most common organs affected by sepsis is the lungs, which, when left untreated, leads to the development of sepsis-induced acute respiratory distress syndrome (ARDS). ARDS is a rapid and progressive noncardiogenic pulmonary that presents with severe hypoxaemia requiring mechanical ventilation (Geyer-Roberts et al. 2023; Zhao et al. 2020). This form of ARDS, associated with sepsis, is known to be more severe and has a poorer prognosis and higher mortality rate than non-sepsis-induced ARDS (Xu et al. 2023; Wang et al. 2024). In a study done by Auriemma et al. (2020), the mortality rate of sepsis-induced ARDS in the critically ill is 27-37%. Thus, early identification and timely appropriate management are crucial in improving clinical outcomes in patients with sepsis (Evans et al. 2021).

Early Recognition of Sepsis

Due to the worldwide impact of sepsis and septic shock, early recognition and treatment are crucial to improving patient outcomes. According to the 2021 International Guidelines for Management of Sepsis and Septic Shock, sepsis screening tool use is recommended. There is an assortment of tools, including Systemic Inflammatory Response Syndrome (SIRS) criteria, National Early Warning Score (NEWS), Modified Early Warning Score (MEWS), and the Quick Sequential Organ Failure Assessment (qSOFA). As the qSOFA score is a predictor of poor outcomes in high-risk patients, it is strongly recommended not to use it as a sole screening parameter but rather in conjunction with one of the other aforementioned tools. Although the sensitivity and specificity of the tools vary, the guidelines still recommend screening as an important element of care, as early recognition leads to prompt intervention (Evans et al. 2021).

Initial Management of Sepsis

As sepsis and septic shock are life-threatening conditions, they warrant immediate treatment upon recognition. The guidelines (Evans et al. 2021) recommend the following initial interventions to stop the progression of sepsis:

• Obtain blood cultures before the administration of antimicrobials when possible.
• Serum lactate should be obtained within an hour of recognition when possible, as a level >2.0 mmol/L can reflect impaired tissue oxygenation, whereas > 4 mmol/L indicates lactic acidosis, a common marker of tissue hypoperfusion and circulatory shock.
• Fluid resuscitation for sepsis-induced hypotension or septic shock should be completed within the first 3 hours of resuscitation. Administering 30 ml/kg (ideal body weight) of a balanced crystalloid solution.
• Broad-spectrum antimicrobial agents should be administered to patients with known or suspected infection. Patients with shock should ideally receive antimicrobial treatment within an hour of recognition. When no signs of shock are present, administration should occur within 3 hours.
• Norepinephrine should be utilised as a first-line vasoactive agent for patients with refractory hypotension despite adequate fluid resuscitation. The goal is to keep the mean arterial pressure (MAP) ≥ 65 mm Hg. Additional vasopressors should be considered when the MAP remains below the goal and/or cardiac dysfunction is present.
• Patients who require intensive care should be admitted within 6 hours.

It is also suggested that capillary refill time and dynamic response parameters are used to guide resuscitation in conjunction with assessment and static parameters. Dynamic parameters such as passive leg raise (PLR), stroke volume (SV), stroke volume variation (SVV), and small-volume fluid challenges (250-500 ml) can help assess if a patient will respond to the additional volume. Seethala et al. (2021) state that excessive fluid administration during the treatment of sepsis and septic shock can lead to pulmonary oedema and subsequent development of sepsis-induced ARDS.

Pathophysiology of Sepsis-Induced ARDS

ARDS has three overlapping phases: inflammatory/exudative, proliferative, and fibrotic (Serazin et al. 2021). During sepsis, the first phase begins with a series of events, starting with the body's overwhelming inflammatory response during a cytokine storm. Cytokines enter the lungs, damaging the pulmonary capillary endothelium, which leads to endothelial leak and lung injury. This initial damage activates and recruits alveolar macrophages, lymphocytes, neutrophils, and monocytes to the affected area, worsening inflammation and further damaging the lung tissue (Xu et al. 2023), leading to non-cardiogenic pulmonary oedema (Vignon et al. 2020). Protein-rich fluid accumulates in the alveolar space, causing injury to the alveolar epithelium (Mayow et al. 2023). The proliferative phase occurs 2 to 7 days after lung injury, where fibrotic changes and alveolar capillary thickening begin to appear. The fibrotic phase can begin 2-4 weeks after injury, resulting in diminished lung compliance and fibrosis. Patients who reach this phase can have symptoms that vary from mild to severe (Serazin et al. 2021).

ARDS Definition

The 2024 Global Definition of ARDS recognises the 2012 Berlin Definition of ARDS, including risk factors and origin of oedema, timing, chest imaging, and severity of ARDS in intubated patients utilising positive end-expiratory pressure (PEEP) and the partial pressure of arterial oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio. The global definition expands the criteria (Table 1) to include non-intubated patients with high-flow nasal oxygen (HFNO), continuous positive airway pressure (CPAP), and those in resource-limited settings, as well as utilisation of pulse oximetry to assess saturation of peripheral oxygenation (SpO₂) and obtain a SpO₂/FiO₂ ratio when oximetry readings are < 97% (Matthay et al. 2024).

Identification and Management of Sepsis-Induced ARDS

Patients with sepsis have approximately a 30% risk for developing ARDS in addition to risk factors including but not limited to age, gender, and alcohol use. At-risk patients should be monitored closely for the onset of symptoms indicative of ARDS, which typically manifest between 72 hours and seven days from the onset of new or worsening clinical symptoms.

Physical signs and symptoms can include dyspnoea, increased work of breathing, abnormal breath sounds such as bibasilar rales, decreased oxygen saturation, hypoxaemia, tachycardia, central or peripheral cyanosis, and altered mental status. Non-cardiac bilateral infiltrates not explained by other causes, such as pleural effusion or pneumothorax, are present on chest imaging (Diamond et al. 2024).

The management of sepsis-induced ARDS primarily involves supportive care with lung-protective ventilation and conservative fluid management (Matthay et al. 2019; Zhang et al. 2024). Balancing adequate intravascular volume to sustain cardiac output while minimising pulmonary oedema remains a challenge in ARDS patients, as excess fluid can impair gas exchange and prolong mechanical ventilation and ICU stays (Lee et al. 2021).

Suggested treatment strategies to mitigate ventilator-induced lung injury, such as barotrauma and volutrauma, include low-tidal volume (6ml/kg) ventilation for sepsis-induced ARDS, higher PEEP vs lower, and a plateau pressure target of ≤ 30 cm H₂O. Increases in plateau pressure indicate decreased lung compliance and are associated with higher mortality (Evans et al. 2021). The ARDSnet Mechanical Ventilation Protocol Summary (2008) provides a lung-protective ventilation guideline that includes but is not limited to inclusion criteria, ventilator setup and adjustment, and oxygenation goals with PEEP/FiO₂ combinations.

Evans et al. (2021) provide additional recommendations for patients with moderate to severe sepsis-induced ARDS, including:

• Using recruitment manoeuvres such as prone positioning
• Intermittent neuromuscular blocking agent boluses versus an infusion to reduce ventilator-patient dyssynchrony and peak airway pressures.
• Use of veno-venous (VV) extracorporeal membrane oxygenation (ECMO) when mechanical ventilation therapy fails. ECMO allows for oxygenation and ventilation independent of the lungs. ECMO should be provided in a centre with skilled, competent staff.

Prone Positioning

Prone positioning is a supportive therapy utilised to recruit alveoli and is an effective method of optimising gas exchange in patients with moderate to severe ARDS. When a patient is prone, the compression of the lungs and diaphragm from the heart structures is offloaded, thereby improving ventilation. Furthermore, overinflation of the anterior portion of the lungs decreases leading to less collapse of the posterior alveoli, resulting in reduced ventilator-induced lung injury (VILI) from volutrauma (overstretching of alveoli) or atelectrauma (repeated opening and closing of alveoli). Finally, when there is an increase in available alveoli, there is no longer a ventilation/perfusion mismatch, leading to improved oxygenation. Proning should be initiated early (12-24 hours) once ARDS with severe hypoxaemia is recognised and mechanical ventilation is optimised. It should be maintained for ≥ 16 hours per day, to have a significant effect on mortality reduction Vollman and Mitchell (2023).

Patients should be assessed for absolute and relative contraindications before initiating prone positioning. Proning must be done with extreme caution to prevent complications such as unplanned extubation, line dislodgment, peripheral nerve injuries, and pressure injuries (PIs). Patients at risk for PIs include vasopressor use, prolonged immobility, and increased ICU length of stay. Areas of the body most at risk for PI during prone positioning include the face, chest/breasts, shoulders/clavicles, iliac crest, penis, knees, and anterior feet, and should be protected with soft foam dressing before proning (Vollman and Mitchell, 2023; Ryan et al. 2021). 

Vollman and Mitchell 2023, recommend the following nursing considerations for proning and returning to supine position: 

• A minimum of five personnel (four to turn the patient and one to monitor the airway). In the event of an unplanned extubation, a provider capable of intubation should be available.
• Equipment and supplies to prep the patient (e.g., ECG leads/pads, bag-valve mask, foam dressings, sheets, pillows, and absorbent pads).
• Assess skin, pain, agitation, and delirium; perform eye care, and verify lines, tubes, and catheters are secure.
• Consider pausing enteral feedings 1 hour before proning.
• Provide patient and family education.
• Utilise the “burrito method” by ensuring the patient is secure between the sheets.
• If available, use overhead lifts to assist as necessary.

Once prone, the bed can be placed in reverse trendelenburg to help offload pressure. Place the patient in the swimmer’s position (i.e. left arm extended up, head turned so right ear is up, and right arm is extended downward); this position should be rotated every two hours. Once proning concludes for the day, the same process is followed to return the patient to the supine. Criteria for the discontinuation of prone positioning may include improved oxygenation in the supine position for at least four hours, failure to show improvement while prone, complications occur, or when there is a shift in the goals of care from recovery to end-of-life (Vollman and Mitchell 2023). 

Nursing Resources

The American Association of Critical Care Nurses (AACN) has a webpage dedicated to sepsis. There is a plethora of resources to guide the nursing care of critically ill patients with sepsis, septic shock, and ARDS. These include but are not limited to practice alerts, webinars, blogs, and National Teaching Institute (NTI) recordings (Table 2). AACN also offers the opportunity for nurses to validate their specialty knowledge by earning micro-credentials for sepsis, ECMO, and COVID-19 Pulmonary and Ventilator Care. These micro-credentials are available for eligible applicants. More information about micro-credentials can be found at https://www.aacn.org/certification/micro-credentials

Research Advancements in Sepsis and Sepsis-Induced ARDS 

Due to the complexity and high morbidity and mortality associated with ARDS, several research studies have investigated its prevention and potential therapeutic strategies. Below are some of these studies (Table 3).

Conclusion

Sepsis is a preventable life-threatening condition. Healthcare providers can prevent sepsis or the progression of sepsis to sepsis-induced ARDS by focusing on early recognition and prevention. Prompt and appropriate interventions can reduce the risk of severe complications and optimise patient outcomes.

Conflict of Interest

None.