Pulmonary Flashcards
(136 cards)
A pleural effusion makes a ____ sound upon percussion?
Dull
A pneumothorax makes a ________ sound upon percussion?
hyper-resonant
What is pulsus paradoxus?
a drop in systolic blood pressure of 10mmHg or more during inspiration
- sign of lung and/or heart disease
- cardiac tamponade
- pericardial effusion
- asthma/COPS exacerbation
- tension pneumothorax
- large pleural effusions
What is the term for a drop in systolic blood pressure of 10mmHg or more during inspiration?
pulsus paradoxus: caused by
- cardiac tamponade
- pericarditis
- tension pneumothorax
- CHF
- acute asthma exacerbation
- COPD exacerbation
What is the normal pulmonary flow rate?
6 L/min
What is the normal mean pulmonary arterial pressure?
12-15 mmHg
What is the normal PaCO2 value?
35-45 mmHg
What is the normal PaO2 value?
75-100 mmHg
- partial pressure of oxygen in arterial blood
What is the normal SaO2?
95-100%
- percentage of O2 binding sites on hemoglobin that are bound to O2
- arterial O2
- low percentage means high number of empty O2 binding sites on hgb
What value shows the percentage of O2 binding sites on hemoglobin that are bound to O2?
SaO2
What is the difference between PaO2 and SaO2?
- PaO2 = O2 in plasma
- SaO2 = 02 bound to hemoglobin
What 2 conditions can cause a shift to the left on the oxyhemoglobin dissociation curve?
- shift to the left = increased affinity of Hgb for O2
- alkalosis
- hypothermia
What does a shift to the left on the oxyhemoglobin dissociation curve mean?
means that hemoglobin has a higher affinity for O2, doesn’t release it to the tissues and binds to O2 in the lungs easily
- can lead to tissue hypoxia
What does a shift to the right on the oxyhemoglobin dissociation curve?
means that hemoglobin has a weak affinity for O2
- hemoglobin readily dissociates from or releases O2 to tissues
- caused by:
- hypercapnia (high CO2) which creates an acidic environment
- pH < 7.35 or acidic
- hyperthermia
What conditions can cause a shift to the right on the oxyhemoglobin dissociation curve?
- acidosis
- increased tissue metabolism
- increased anaerobic metabolism
- hyperthermia
What is the normal Svo2 value (O2 in venous blood returned to heart)?
60-80%
An SvO2 < 60% is indicative of what?
- amnt of O2 returning to heart
- normal: 60-80%
- increased O2 demand (fever, shivering, increased WOB, pain)
- decreased O2 Supply (may not be oxygenating or may be alkalotic)
An SvO2 < 40% indicates?
- anaerobic metabolism leading to organ dysfunction
- increased O2 demand or decreased oxygenation
An SvO2 > 80% implies?
- decreased tissue extraction of O2
- less O2 demand (sleep, hypothermic)
- decreased O2 delivery and cell uptake (sepsis, shift of curve to the left)
- increased O2 supply (polycythemia, FIO2 > need)
What does PEEP on ventilator stand for?
Positive End Expiratory Pressure
- pressure at end of expiration to keep alveoli from collapsing
What is PEEP in ventilation?
- Positive End Expiratory Pressure
- pressure applied by the ventilator at the end of each breath to prevent alveoli collapse
Which part of the brain controls the involuntary act of breathing?
Brainstem (medulla and pons)
Why should O2 be administered at low flow rates and titrated carefully in patients with chronically high PaCO2?
- patients have lost the normal hypercapnic drive and respond only to changes in PaO2
- increased PaO2 may result in suppression of ventilation
What is the ratio of CO2 to O2 exchange between the alveolus and capillaries?
- 20:1
- 20 CO2 cross from capillaries for every 1 O2