Patients in the critical care setting are more susceptible to Health Care Associated Infections (HCAIs), making infection prevention and control even more crucial within this setting. Some of the most common infection manifestations in the critically ill patient include pneumonia following intubation, bloodstream infections following IV catheterisation, and UTIs following urinary catheterisation.
Susceptibility to HCAIs within the critically ill population can be due to:
- altered immunity – due to steroid use, surgery, anaesthesia and age
- invasive lines – provide direct entry of bacteria into the patient’s bloodstream
- underlying illnesses or conditions
- broad spectrum antibiotics
- mechanical ventilation
These risks cause an increased morbidity and mortality rate, a longer hospitalisation stay, and subsequently, higher treatment costs.
Antibiotic Use
We are currently witnessing a dramatic increase in infections by multi-drug resistant pathogens, leading to difficult infection management due to the scarcity of available antibiotics. Even more so, within the critical care setting there is an increased risk of patient-to-patient transmission, increased antibiotic use, and critically sick patients.
Multi Drug Resistant organisms (MDRO)
GRAM POSITIVES
- VRE – Vancomycin-resistant Enterococci
- MRSA – Methicillin-resistant Staphylococcus aureus
GRAM NEGATIVES
- CRE – Carbapenem-resistant Enterobacterales
- Pseudomonas aeruginosa CRE
- ESBL-positive bacteria
OTHERS
- Clostridium difficile
- Neisseria meningitidis
- Mycobacteria tuberculosis
Infection Prevention and Control in the ICU Setting
General Preventive Techniques
- follow the 5 moments of hand hygiene
- alcohol hand rub should be the first hand hygiene choice – unless hands are visibly soiled
- nails should be kept well trimmed with no gels
- reduce jewellery use to just one plain wedding band if necessary
- keep patients with MDRO in isolation rooms if possible
- allocate equipment to one patient without sharing
- screen patients for MDRO, specifically for MRSA, CRE and VRE on admission and at least weekly thereon
- promote awareness on ANTT (aseptic non-touch technique) amongst colleagues
- ensure disinfection of shared equipment such as monitoring lines, saturation probes, ECG leads, and blood pressure cuffs
- promote education on infection prevention and control for staff and cleaners
- educate patients’ relatives on infection prevention and control measures
- ensure appropriate antibiotic use
- ensure terminal cleaning of bed area upon patient discharge
Glove Use
- change gloves between procedures on the same patient when performing dirty vs aseptic tasks
- change gloves between patients
- don gloves immediately before contact with patient body fluid, mucous membranes, or non-intact skin
- remove and discard immediately after a procedure and perform hand hygiene so that contamination is not transferred to another patient
Rectal screening for CRE and VRE
- insert a charcoal swab approximately 2cn inside the rectum and rotate gently
- ensure swab is brown-stained with faeces to ensure a good sample has been taken, as inadequate samples are not processed by the lab
Bathing Patients in Critical Care Setting
- as previously mentioned, there is a high prevalence of MDROs in the critical care setting
- daily chlorhexidine bathing of patients in the critical care setting is encouraged since chlorhexidine helps reduce the risk of acquiring MDROs
- washing the patient’s body with chlorhexidine has been showing effectiveness in the prevention of carriage and possibly bloodstream infections with Gram-positive MDROs (MRSA and VRE)
- chlorhexidine washes have shown possible eradication of carriage and infection prevention of Gram-negative MDROs, however, more evidence is required in this regard
Disinfecting Isolation Rooms
- isolation rooms should be disinfected on a daily basis
- isolation rooms should be cleaned last using yellow cloths, disposable gloves, and chlorine-based disinfectant
- terminal cleaning and disinfection of isolation rooms should be done following patient discharge; all surfaces need to be cleaned with detergent; mattresses and pillows should be cleaned with environmental disinfectant wipes; UV-C disinfection should be performed, by which more than 99.9% of C. difficile spores and MRSA are killed in minutes
ADVANTAGES OF USING CHLORINE-BASED DISINFECTANT:
- inexpensive
- low toxicity
- rapid effect
- broad spectrum disinfectant – bacteriocidal, tuberculocidal, fungicidal, virucidal
DISADVANTAGES OF USING CHLORINE-BASED DISINFECTANT:
- corrosive
- long contact time
- employee complaints
The Nurse’s Role in Proper Antibiotic Management
- knowledge on antibiotic resistance
- knowledge on the most frequently used antibiotics within the critical care setting
- knowledge on the disadvantages of using broad spectrum antibiotics – prolonged use increases risk of C. difficile
- administer antibiotics at the recommended dosage intervals for optimal effectiveness
- administer IV antibiotics safely and effectively, with diligence to dosage, dilution, timing and calculations
- administer IV antibiotics to patients with sepsis within 1 hour following diagnosis to increase risk of survival
- list reminders for antibiotic review eg. stop date, reason for prescription, change of route, etc
- therapeutic monitoring of antibiotic levels eg. Gentamicin, Amikacin and Vancomycin require serum blood level checking for safe and effective treatment; ensure samples are taken at the appropriate time for best results
- understand when to withold an antibiotic dose until results are available eg. in the case of Gentamicin
- serum blood level samplings should be properly documented in both the patient’s notes and on the lab request form
- proper handover on transfer from ICU to another ward
Ventilator Associated Pneumonia (VAP)
Pneumonia is an infection in the lung parenchyma, particularly in the bronchioles and alveoli, which is caused by pathogens such as bacteria, fungi and viruses.
Ventilated Associated Pneumonia (VAP) is pneumonia which develops 48 hours following intubation and initiation of mechanical ventilation. VAP is considered to be the 2nd most common HCAIs but the most serious one, with 25% of these patients with VAP ending up dead.
VAP happens because intubation bypasses all natural defense mechanisms within the tracheo-bronchial tree that protect the lower respiratory tract from infections.
Causative organisms, some of which are often present in the oropharyngeal cavity and the gastrointestinal system, are:
- Gram-negative aerobes – Pseudonomas aeruginosa, Klebsiella pneumonia, Acinetobacter, Enterobacter
- Gram-positive aerobes – Staphylococcus aureus/MRSA
There are 5 defense mechanisms which are bypassed during ventilation:
- The Larynx and the Glottis – prevent aspiration of oral content
- The Coughing Reflex – helps in the expelling of secretions and aspirated matter from the larger airways
- Mucous – helps trap small particles
- Cilia – hair-like structures which help move mucous up from the lower respiratory tract towards the larynx to be expelled
- Phagocytic Cells – engulf bacteria if or when they manage to reach the alveoli
Aspiration of contaminated fluids and secretions into the lungs can happen in various ways:
- colonisation of pathogenic bacteria within the oropharynx or tracheo-bronchial tree
- the stomach, through enteral feeding, certain drugs (eg. stress ulcer prophylaxis), and supine patient positioning, may act as a source of pathogens for VAP
- inhalation of aerosols through contaminated intubation or nebulisation equipment
Pathological development of pneumonia
- aspiration of contaminated fluids or secretions into the lungs
- initiation of the inflammatory response
- swelling of the mucous membranes of the alveoli and bronchi
- pus collects within the alveoli
- interference of pus with the gas exchange process
- development of pneumonia
Signs & Symptoms of VAP Pneumonia
- temperature of >38°C
- tachypnoea and/or dyspnoea
- purulent sputum (off-white, yellow or green, and opaque)
- worsening ABGs – poor SaO2 and increased ventilatory demands
- positive sputum and/or blood cultures
- leukocytosis >12,000 WBC/mm2
- chest x-ray or CT scan with evidence of pneumonia
NOTE: Diagnosing VAP can be difficult!
VAP Risk Factors
- length of time in which the patient is exposed to the healthcare environment
- predisposing host-related factors such as age, malnutrition etc
- treatment factors eg. endotracheal intubation, prolonged exposure to antibiotics
VAP Consequences
- increased mortality
- prolonged mechanical ventilation
- increased antibiotic use
- prolonged stay at the ITU and hospital
- increased medical cost
VAP Infection Prevention and Control
- do not intubate patient unless necessary
- choose non-invasive ventilation over invasive ventilation where possible
- elevate head of bed 30-45° especially for patients receiving enteral feeding
- minimise aspiration of contaminated oropharyngeal and tracheal secretions
- suction subglottic secretions
- avoid gastric over distention
- avoid unplanned extubation
- maintain correct ETT cuff pressure (20cm H2O)
- provide frequent oral hygiene – suctioning, toothbrushing, and using chlorhexidine mouthwashes
- use HME filters rather than heated humidifiers
- remove condensate from ventilatory circuits periodically
- extubate as soon as possible
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