A change in PEEP within values of 0–5 cmH2O is not considered an increasing requirement of oxygen. For example, a change in PEEP from 0 to 3 cmH2O is not considered an increasing requirement of oxygen because it stayed within the 0–5 cmH2O value. Baseline stable FiO2 or PEEP is the lowest value of oxygenation maintained for at least 1 h. If these requirements are met, then it is categorized as a ventilator-associated condition (VAC), such as the following:
Pneumonia
Acute respiratory distress syndrome (ARDS)
Lobar atelectasis
Pulmonary edema
In the setting of a VAC, if the patient has been on mechanical ventilation for 3 or more days or is within 2 days of worsening oxygenation, as described above, with the following added criteria below, then it considered an infection-related ventilator-associated complication (IVAC):
Temperature >38 or <36 °C or white blood cell count ≥12 or ≤4 and
A new antibiotic is used and continued for 4 or more days
After all these events, if there is Gram stain evidence, inflammatory cells or culture above a certain threshold from the lungs, bronchi, or trachea, or cultures direct from bronchoscopy, then it is classified as possible VAP. If the culture shows growth surpassing specific thresholds or there are specific positive test findings or histopathology, then VAP is considered probable.
16.2 Interventions and Practices Considered for Prevention of VAE
Following is a list of interventions and practices considered for prevention of VAE:
1.
Elevate the head of the bed
2.
Maintain cuff pressure in the endotracheal tube between 20 and 25 mmHg
3.
Circuit changes
4.
Use heated humidifiers and heat and moisture exchangers
5.
Provide oral care with chlorhexidine and water-soluble mouth moisturizer
6.
Secretion removal with specially designed endotracheal tubes
7.
Closed, in-line suctioning (no recommendation made)
8.
Evaluation for kinetic bed therapy
9.
Sedation reduction
10.
Assessment of weaning readiness with brief weaning trials
11.
Stress ulcer disease prophylaxis
12.
Deep vein thrombosis prophylaxis
In 2014, the Society of Healthcare Epidemiology (SHEA) and the Infectious Disease Society of America (IDSA) released a newly updated guideline for Strategies to Prevent VAP in the Acute Care Hospitals [1]. The Basic Practices Guidelines are listed as below:
Avoid intubation
Minimize sedation
Provide physical conditioning
Minimize secretions above the endotracheal tube cuff
Elevate the head of the bed
Maintain ventilator circuits
16.2.1 Intubate Only If Necessary and Utilize Noninvasive Mechanical Ventilation Strategies
The presence of an endotracheal tube (ETT) can interfere with the protective mechanism of cough, which results in pooling of secretions in the upper airways, promoting micro-aspiration. Studies have shown that use of noninvasive ventilation (using devices such as BiPAP®) has decreased the need for invasive mechanical ventilation, and ultimately the incidence of VAP, with a resulting decrease in length of stay in the intensive care unit (ICU). Noninvasive mechanical ventilation can assist in liberation from mechanical ventilation and prevent reintubation, especially in patients with chronic obstructive lung disease (COPD). Attempts to reduce the number of ventilation days and need for reintubation will decrease the incidence of VAP. Strategies to avoid premature and unplanned extubation should be in place.
16.2.2 Minimize Sedation
Strategies and development of approaches to limit the use of sedation in the ICU have been associated with successful spontaneous breathing trials and early extubation. Efforts should be made to limit the need for sedation and should follow the guidelines for analgesia and sedation. Other helpful tips include:
Use of shorter-acting sedative agents. Use of antipsychotics, dexmedetomidine, propofol, and other shorter-acting agents rather than benzodiazepines
Sedation holidays. Stopping sedation infusions to allow the patient to be fully awake. Randomized control trials have shown that daily sedation holidays can decrease the average time of intubation by 2–4 days, thus minimizing the risk of developing VAP
Daily spontaneous breathing trials
Daily assessment of extubation
16.2.3 Physical Conditioning
Early exercise and mobilization can prevent the development of critical muscle weakness, expedite extubation, and improve overall quality of life for the patient.
16.2.4 Patient Positioning
The head of the bed should be elevated to 30–45°. Most meta-analyses and studies have shown that patients whose beds are elevated to 30–45° are have less risk of aspiration compared with patients placed in a fully supine position [1]. However, although incidence is lower, there has been no proven mortality benefit.
16.2.5 Subglottic Drainage
ETTs with specialized capabilities to provide subglottic secretion drainage (SSD) are available but are costly. These devices can provide either continuous drainage or intermittent drainage of the secretions and fluids near the subglottis, thus decreasing the risk of aspiration and VAP [7].
A 2011 meta-analysis of 13 randomized controlled studies with 2442 patients compared standard ETT and ETT with SSD capabilities. Twelve of the 13 studies showed a decrease in rates of VAP. There were associations with decrease in length of days of intubation, decrease in length of days spent in the ICU, and increased length to first episode of VAP. However, despite these positive findings, there was no difference in adverse events and mortality in patients with predicted prolonged mechanical ventilation (>48–72 h).
16.3 Ventilator Circuit Maintenance
Routine change of the circulatory circuit is not required unless contaminated with soiled secretions or if it is malfunctioning.
The following strategies may assist in the prevention of VAP but the evidence is not as concrete.
Related posts:
Predictive Models of Prolonged Mechanical Ventilation and Difficult Weaning
Noninvasive Technique of Nasal Intermittent Pressure Ventilation (NIPPV) in Patients with Chronic Obstructive Lung Disease After Failure to Wean from Conventional Intermittent Positive-Pressure Ventilation (IPPV): Key Practical Topic and Implications
Noninvasive Mechanical Ventilation in Postoperative Bariatric Surgery
Noninvasive Mechanical Ventilation in Tetraplegia
Criteria for Discharging Patients with Prolonged and Difficult Weaning from Intensive Care Unit to Weaning Center
Organization of a Weaning Unit
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