WEEK TWO Flashcards
what is the V/Q Ration?
The relationship between ventilation(V) and perfusion(Q)
Ventilation is?
Mechanical movement of air to and from the atmosphere and the alveolar (in and out of the lungs)
Perfusion is?
The pumping or flow of blood into the tissues and organs
What are the Acid-Base Normal Parameters?
PH 7.35-7.45 PaO2 80-100mmHg PaCO2 35-45 mmHg HCO3 22-26mmol/l BE +- 3mmol/l Saturation >94.5 – 98.2%
Questions to ask regarding Acid-base parameters?
pH acid or alkaline
PaO2 Hypoxemia? (PaO2 80-100mmHg)
PaCO2 resp acidosis (PaCO2 above 45mmHg) or resp alkalosis (PaCO2 below 35mmHg)
HCO3 any signs of metabolic acidosis/alkolosis
(pH compensated? (pH, PaCo2 & HCO3 abnormal= uncompensated, pH norm but PaCO2 and HCo3 abnormal = compensated)
What is respiratory acidosis caused by?
- Alveolar hypoventilation
- Alveolar hyperventilation
- Mechanical ventilation
- Inadequate perfusion
Use of compensatory mechanisms?
- Initial response: Increased resp rate and depth of breathing
- Increase in minute ventilation
- Increase heart rate
- Possible vasoconstriction
- Peripheral chemorecptors detect hypoxia and initiate compensatory mechanisms
Clinical presentation of respiratory failure?
Respiratory failure Type 1 -Hypoxaemic -Low pa02 -Normal or low paC02 -Mismatch between ventilation and perfusion
Type 2
- Hypoxaemic, hypercapoenic
- High paCO2 and low Pa02
- Alveolar hypoventilation
What is the oxyhaemoglobin dissociation curve?
- Relationship between oxygen and oxygen saturation
- Oxygen molecules bind as partial pressure increases
Why is the ODC important?
In the tissues the oxygen-haemoglobin dissociation curve shifts to the right as the ph increases or temperature rises
In the lungs, the oxygen-haemoglobin dissociation curve shifts to the left as the ph increases, pCo2 decreases or the temperature falls resulting in an increased ability of haemoglobin to pick up oxygen
What is non invasive ventilation?
- Non Invasive Positive Pressure Ventilation delivers positive pressure breaths to a spontaneously breathing patient.
- Delivered by a mask with an airtight seal
- Reduces the occurrence of patients being intubated
What is CPAP?
- CPAP (Continuous positive airway pressure)
- Support for spontaneously breathing patients and ventilated patients
- Non invasively via a mask
- Addition to mechanical ventilation
- The raised positive pressure assists in reducing the work of breathing on inspiration
- Increases gas exchange and reduces hypoxia
What is BiPAP
Bias (Bilevel positive airway pressure)
Involves-
-IPAP (Inspiratory positive airway pressure)
-A higher pressure is delivered on inspiration
-EPAP (Expiratory positive airway pressure)
-Lower pressure (but still positive) on expiration
BiPAP is commonly used in?
- High dependency patients
- Neurological disorders (Guillain Barre syndrome)
- OSA (Obstructive sleep apneoa)
- COPD
- Asthma
- Post extubation weaning issue
What is mechanical ventilation?
-Invasive Positive Pressure Ventilation
Indications:
-Inability to protect own airway (gag response diminshed, GCS reduced)
-Inadequate breathing pattern rate and/or depth (vital capicity <15mL/kg; resp rate < 10 or > 30/min)
-Inability to sustain O2 demands of the body PaO2 <55 mmHg, with supplemental O2,
hypercapnia PCO2 > 50mmHg with acidosis pH< 7.3