Respiratory Flashcards
In a kid with tracheobronchial obstruction due to a foreign body, what would you use for induction?
Inhaled induction with Sevoflurane. This will keep the patient spontaneously breathing. IF you place the kid on mechanical ventilation, you risk pushing the object further into the lungs
What treatment modality can you use to decrease splinting in patients who have just received thoracic surgery or upper abdominal surgery?
Thoracic epidural. This is > incentive spirometry because IS is limited by pain
What is the difference between PaO2 and SaO2?
PaO2: This is the partial pressure of O2 in the blood
SaO2: This is the amount of hemoglobin that is bound to oxygen. This is a calculated number and it assumes that all hemoglobin is normal hemoglobin.
What might a capnogram look like if a patient has COPD and had a single lung transplant?
It will have a sharp initial downward spike and then will rise prior to inhalation
What factors affect the DLCO?
- membrane thickness and integrity
- Cardiac output
- Hgb
- Clots (aka PE) decrease the amount of CO that is able to be absorbed by the lung
What is the physiologic dead space equation?
- Vd/Vt = (PaCO2-PeCO2)/PaO2
What will an INTRAthoracic obstruction look like on flow volume loops? What will EXTRAthoracic obstruction look like? Fixed obstruction?
- INTRAthoracic obstruction will have blunting of the EXPIRATION phase
- EXTRAthoracic obstruction will have a blunting of the INSPIRATION phase
- Both will be blunted
What muscles are used during forced exhalation?
Abdominal wall muscles, including the internal and external oblique muscles as well as the transverses abdomens
When storing RBC for transfusion, what change occurs in the Oxygen dissociation curve, and why?
- The curve shifts to the L
2. This is due to a decrease in 2,3 DPG levels
Describe some anesthetic considerations in a patient with CF?
- Avoid anticholinergics, as these will dry out their secretions and make them more thick
- Higher FiO2 to reduce PVR
- Increased airway reactivity
- Increased risk for spontaneous PTX
- Decreased Vitamin K and therefore bleeding risk is increased
Describe the metabolic compensation seen in chronic vs. acute respiratory acidosis.
- Acute respiratory acidosis leads to a 2 mm/mol increase for every 10 of CO2 over 40
- Chronic respiratory acidosis means that there is a 4 mol increase for every 10 of CO2 above 40
Describe diffusion hypoxia, aka the “Fink” effect.
the Fink effect is caused by the use of high dose N20 at 70%. Because N20 comes off so quickly, it causes a displacement of CO2 and O2 into the alveoli, which then leads to transient hypoxia that lasts for 5-10 minutes. This can be offset by using supplemental O2 during the offset of the gas.
What are the causes of hypoxemia following placement of a patient in Trendelenburg? What effect does Trendeleburg have on CI?
- Reduction in chest wall compliance
- Reduction in TLC
- Endobronchial intubation (as the abdomen pushes up, the tube remains secure and can be pushed into the R bronchus. Suspect this if a patient desaturates immediately following placement in Trendelenburg)
- Increased pulmonary shunting
- Reduction in lung compliance
- It INCREASES CI due to a transient increase in venous return
How long should a patient stop smoking prior to surgery? What are the effects of smoking cessation and how long do each of them take?
- Patients should stop smoking 8 weeks prior
- You will see an increase in O2 delivery to tissues and decreased CO levels in one day
- 48-72 hours: Increase in secretions and RAD
- 2-4 weeks: Decrease in secretions and airway reactivity
- 4-6 weeks: improvement in immune system
- 8-12 weeks: better mucociliary movement and overall small airway function
What is the normal PaO2 to PAO2 ratio in spontaneously breathing patients? mechanically ventilated?
- Spontaneous: the arteriolar CO2 is always 2-5 higher than the end tidal CO2
- Mechanical: the arteriolar CO2 is always 5-10 higher than the end tidal CO2