Anaesthetics - Critical Care Flashcards
what is critical care?
- Organ system support
- Single vs multiple
Can be a bit murky — respiratory failure needing oxygen can be managed on wards, for instance
Closed admissions — not everyone will get in, needs to be on need/benefit
Level 1 care – ward based care
Level 2 care – high dependency unit
Level 3 care – intensive care, multiple different organs needing supported
what is respiratory failure and what types of them is there?
Respiratory failure is a condition in which your blood doesn’t have enough oxygen or has too much carbon dioxide. Sometimes you can have both problems.
- Type 1: oxygenation failure
- Type 2: oxygenation and ventilation failure (In type 2 there is 2 problems, cant clear CO2 which is their ventilation)
what is the treatment/management of respiratory failure?
Can give only a certain amount of oxygen on a ward
Can give it nasal cannily
Can get a normal face mask
If really struggling then you will get a trong mask, reservoir bag hanging off it
These are all ward based therapy
In high flow nasal cannula you can give more as you are warming and humidifying the air first so the patient can have more – we use this for type 1 respiratory failure
Treatments for respiratory failure may include oxygen therapy, medicines, and procedures to help your lungs rest and heal
a non-invasive ventilator can also be used to treat respiratory failure, what is it?
Non-invasive ventilator – NIV
Apply pressure to patients airways to keep them open and reduce their work of breathing
Applying positive pressure to open up alveoli and improve respiratory failure
NIV is mainly for type 2 respiratory failures e.g. COPD patients that are retaining CO2
Use as a means to avoid invasive ventilation
what is shown here? it is another way to treat respiratory failure
Invasive ventilation
Intubate patients
Endotracheal tube
Tube that sits in trachea and the cuff inflates and forms a seal and means any pressure of gas going into lungs can come back up through the patients mouth and also protects the patients airways, e.g. patients has secretions or vomits and sits into the oropharynx then it can go down into the lungs causing more problems
Creates large amounts of pressure
Inspiratory failure or infection can get better or long term the patient requires prolonged ventilation and therefore cant eat so need nasogastric tube, cant talk, take medication
Get a tracheostomy put in neck if long term and therefore bypasses problem with eating and sedation
what is cardiovascular failure?
Shock is acute circulatory failure with inadequate or inappropriately distributed tissue perfusion resulting in cellular hypoxia
Inability of body to get oxygen from outside world to bodily tissues
These are the many different types of causes
what are the types of cardiovascular failure?
- Distributive (septic) – blood vessels have abnormally dilated and blood going wrong place
- Hypovolaemic – not enough blood to go around
- Anaphylactic – blood vessels abnormally dilated and degree of pump failure aswell
- Neurogenic - trauma to spinal cord and destruction of sympathetic system leads to incorrect distribution and dilation of vessels
- Cardiogenic - pump failure, heart itself is the issue
Cardiovascular failur - what do you Need to think about when deciding on what drugs to use
- Cardiac Output = Heart Rate x Stroke Volume
- Stroke Volume = Preload / Contractility / Afterload
BP is not fundamental to your CO
HR easy to measure but SV is harder to physically quantify
cardiovascular failure - what is shown here?
an arterial line – introductory needle, guide wire and a canula that slides over the guide wire into the vessel
Get an instant measure of the patients BP
Can do repeated blood sampling without need of further needling of the patient
cardiovascular failure - what is shown here?
picture of essential line in an essential vein, able to give number of different potent drugs right into circulation and if gave peripherally would be dangerous
Also can aspirate from it and check central venous pressure
what drugs are used for cardiovascular failure?
Most common drugs we use in critical care to support cardiac failure:
•Vasopressors:
- Metaraminol
- Noradrenaline
•Inotropes:
- Adrenaline
- Dobutamine
Vasopressors - vasocontraction, improve preloads, reduce venous volume
If patients main issue is pump dysfunction and need support for contractibility then use an inotrope
Vasopressors are a powerful class of drugs that induce vasoconstriction and thereby elevate mean arterial pressure (MAP). Vasopressors differ from inotropes, which increase cardiac contractility; however, many drugs have both vasopressor and inotropic effects
an agent that alters the force or energy of muscular contractions
what types of fluids is there?
Colloids or crystalloids
There are two main types of volume expanders: crystalloids and colloids. Crystalloids are aqueous solutions of mineral salts or other water-soluble molecules. Colloids contain larger insoluble molecules, such as gelatin; blood itself is a colloid. There is no evidence that colloids are better than crystalloids in those who have had trauma, burns, or surgery. Colloids are more expensive than crystalloids. As such, colloids are not recommended for volume expansion in these settings
Colloids and crystalloids are types of fluids that are used for fluid replacement, often intravenously (via a tube straight into the blood). Crystalloids are low-cost salt solutions (e.g. saline) with small molecules, which can move around easily when injected into the body
what is a colloid?
large osmotically active particles and molecules in to, idea is that the molecules will stay in the vascular tree and not move into tissue as easy, increases risk of renal failure
what are crystalloids?
use more commonly, small molecules in them, e.g. saline, some fluid stays in intravascular tree but a lot does leak out into tissue and cells and gets distributed in the body
The most commonly used crystalloid fluid is normal saline, a solution of sodium chloride at 0.9% concentration, which is close to the concentration in the blood (isotonic).
Crystalloid fluids function to expand intravascular volume without disturbing ion concentration or causing significant fluid shifts between intracellular, intravascular, and interstitial spaces
what may fluids be given for?
Maintenance or resuscitation
