W2 Respiratory Flashcards
- Respiration:
gas exchange between the atmospheric air and the blood and between the blood and the cells of the body.
- Ventilation:
the movement of air, in and out the lungs. (Normal alveolar ventilation 4L/min)
- Perfusion:
is the blood that flows through the vascular system, delivering oxygen and nutrients to organs and tissues. Pulmonary perfusion is blood that flows through the pulmonary vasculature, reaching the alveoli for the transfer of gases. (Norm cap perfusion 5/min. V/Q ratio = 0.8
- Diffusion:
the exchange of gas molecules from areas of high concentration to low concentration.
- Dead space:
is the space of the brachial tree that does not participate in gas exchange due to a high volume of gas and under perfusion. Alveolar dead space the area in the lungs that is under perfused and does not participate in gas exchange. Can be impacted by positioning, respiratory diseases (Emphysema), Positive airway pressure (CPAP), PE, Hypotension.
- Orthopnoea:
increased WOB when lying down.
- Non Invasive ventilation:
Delivers positive pressure breaths to a spontaneously breathing patient, increasing the patient’s breath size via a non-invasive device.
- Invasive mechanical ventilation:
The patient is assisted to breathe by an artificial airway which is connected to a mechanical device, which is used to assist or replace spontaneous breathing. Used on patients who are unable to maintain own airway (absent gag reflex, GCS), inadequate breathing rate/pattern and inability to sustain bodies oxygen demands with supplemental oxygen. (Respiratory failure, acute lung injury, asthma, COPD, pneumothorax, PE, pneumonia, acute respiratory distress syndrome).
Continuous Positive Airway Pressure:
CPAP is a type of ventilator support for spontaneously breathing patients. CPAP reduces the work of breath on inspiration, promoting gas exchange by reducing hypoxia. CPAP can be delivered through non-invasive or addition to invasive ventilation. Commonly used for Pulmonary Oedema, atelectasis, COPD, asthma, apnoea, respiratory failure type 1)
- Bi level Positive Airway Pressure
BiPAP involves two levels of positive airway pressures. A higher pressure is delivered on inspiration and lower pressure on expiration, ideally controlling lung expansion. Commonly used when CPAP not tolerated, COPD & Asthma to eliminate Co2, obstructive sleep apnoea, neurologic/neuromuscular disorders, weening off mechanical ventilation.
Normal ABG Ranges
pH:
Pco2:
HCO3:
pH: 7.35-7.45 (Acid < > Base)
Pco2: 35- 45 (Base < > Acid)
HCO3: 22- 26 (Acid < > Base)
What causes respiratory acidosis?
1) Alveolar hypoventilation- insufficient ventilation leading to hypercapnia. (Lower respiratory tract infections, ARDS, acute lung injury, neuromuscular disorder, respiratory failure).
2) Alveolar hyperventilation- (Anxiety, stress, DKA, COPD, asthma, pain).
3) Mechanical ventilation inadequate- under or over ventilate
4) Inadequate perfusion- as a result of hypovolaemia, PE, heart failure
How does the body compensate for Respiratory Acidosis? (signs)
o Rate and Depth of breathing increases- (breath of the excess Co2)
o Use of accessory muscles
o Increased heart rate (increase blood flow to the lungs)
o Vasoconstriction (depending on cause/shunts blood away from the under ventilated lung region)
o Patient cyanotic, confused, anxious, lethargy/sleepy.
Define Respiratory failure:
• ARF is a syndrome in which the respiratory system fails to carry out adequate gas exchange. This can involve one or both of the gases, oxygenation or/and carbon dioxide expulsion.
Characteristics of Type 1 Respiratory failure and what is it caused by?
(Hypoxaemic)
- Characterised by low oxygen levels in blood with no increase in Pco2
- Low/normal PCo2 levels
- Mismatch between ventilation and perfusion
- Causes: pneumonia, pulmonary oedema, atelectasis, acute lung injury