Critical Care Flashcards
What is mechanical ventilation?
MV replaces the function of the inspiratory muscles by delivering gas under positive pressure to the lungs.
Either the ventilator or the patient “triggers” inspiration. If the patient triggers it, the ventilator delivers the breath as soon it senses the beginning of the patients inspiration
What is lung compliance?
The ability of the alveoli and lung tissue to expand on inspiration. Compliance varies depending on the elasticity and surface tension of the lungs . The stiffer the lung the less compliant. Poorly complaint Kung so are harder to mechanically ventilate.
What are the indications to ventilate?
Respiratory failure Prolonged post op recovery Altered conscious level Inability to protect the airway Inadequate gas exchange as reflected in ABGS
What are the two types of respiratory failure?
Hypoxaemia- failed oxygenation due to failure of the gas exchanging function of the respiratory system
Hypoxaemia and hypercapnia (increased o2) failed ventilation, raised co2 is caused by failure of the respiratory pump
What does PEEP stand for?
Positive End Expiratory Pressure.
It is pressure maintained in the alveoli at the end of expiration to prevent alveolar and airway collapse
What is volume controlled ventilation?
Ventilator delivers a pre set tidal volume, pre set inspiratory time, pre set pause time and a pre set respiratory rate. Airway pressure rises slowly as the ventilator reaches the desired volume
What is pressure controlled ventilation?
Flow is delivered to a pre set target pressure limit during inspiration, pre set respiratory rate, pre set inspiratory time, pressure is constant and set so the volume can change from breath to breath depending on lung compliance. Better lung compliance leads to larger lung volume. Poorer lung compliance leads to smaller volumes.
The main advantage is that pressure can be controlled reducing the risk of barotrauma (injury sustained because of changes in barometric air pressure) in patients with stiff lungs.
What is CPAP and what does it do?
CPAP stands for continuous positive airway pressure. It provides positive pressure but with no mandatory breathes so the patient has to breath spontaneously. It increases FRC improving gas exchange by splinting open the alveoli. It delivers the same flow of gas through inspiration and expiration. It is likened to putting your head out of the window of a speeding car.
Some key messages about mechanical ventilation
Invasive mechanical ventilation can be
1.controlled by pressure
2.controlled by volume
Or a combination of both
Ventilation can be fully controlled by the machine CMV or can allow for some synchronisation with the patients effort SIMV.
Spontaneous modes like PS, ASB and CPAP need the patient to be able to indicate a breath or they won’t provide and support for ventilation.
PEEP is required to hold the alveoli open at the end of expiration otherwise they would collapse
What is heart rate and rhythm affected by?
Physiotherapy Hypoxia Electrolyte imbalance Myocardial ischaemia Anxiety
What complications can occur during a line in one of the major arteries such as the femoral artery?
If the patient sits up and puts pressure on the legs before 12 hours has passed, the line in could burst.
An ischaemia can occur if it occludes or bleeding could occur if it becomes dislodged
What is the role of physiotherapists on critical care?
Maintenance and improvement of cardio respiratory status.
Maintenance of MSK function
Optimisation of neurological status
To work as part of the wider critical care MDT.
Weaning/liberating patients from mechanical ventilation.
Extubating/decannulation
What information gathering should you do for a patient on the intensive care ward?
Subjective
- ask about emotional status, symptoms
, fatigue, SOB, specific problems, ask nursing staff how the patient is, what has happened since the last PT treatment, are there any limitations to movement/handling.
What to look at in a general observation for an ICU patient?
Face/colour/expression Position/posture/comfort Equipment/ attachments/drips/ drains Skin/wounds Peripheries/oedema/cyanosis
What to assess in the respiratory system for someone on the ICU ward?
Mode of ventilation 1 or 2 or both? Method of delivery (ETT/tracheostomy/face ask) ventilator settings Oxygen delivered/mode of delivery RR ABGS and Pulse oximetry CXR Previous Pulmonary function test Auscultation Chest wall shape and expansion Palpation Cough/sputum/suctioning Breathlessness/cyanosis/ work and pattern of breathing
