Quiz 8 - Pulm Intraoperative Monitoring & Difficult Airway Flashcards
What is dCO2?
It is the normal ETCO2 to PaCO2 gradient (usually 2-5mmHg
If there is a significant reduction in lung perfusion or increase in alveolar dead space, will your dCO2 increase or decrease?
It will increase
Why will PaCO2 always be higher than ETCO2?
this is due to mixing and dilution with the dead space gases
What can cause an increased dCO2?
Anything that increases deadspace: decreased pulmonary artery pressure, PE, COPD, decreased cardiac output, upright posture.
What is the first thing you should worry about if you have an increasing ETCO2?
Malignant Hyperthermia.
Other than Malignant Hyperthermia, what are some other causes of elevated ETCO2,?
Hypoventilation, CO2 used for laparoscopy, Hyperthermia, tourniquet released, WATER IN CAPNOGRAPH SENSOR, Breathing circuit error (CO2 absorber exhausted, rebreathing, inadequate fresh gas flow, faulty valves)
What are some causes of decreased ETCO2?
Hyperventilation, airway leak (ET tube cuff leak), decreased pulmonary blood flow, PE, decreased cardiac output, arrythmias, hypothermia, sample catheter misplaced.
Once again, what are the normal ABG values?
pH: 7.4 (7.35-7.45) PCO2: 40 (35-45) HCO3: 24 (20-26) PO2: 75-100 Base excess: +/- 3
If you have sedated a pt and are unable to intubate, what should you do?
Call for help.
T/F: Pulse oximetry is a mandatory during intraoperative care?
Answer: True
What is the wave length of infrared light?
Answer: 940 nm
- What is the wave length of red light?
Answer: 660
- Oxyhemoglobin absorbs more of this light and corresponds to 100% saturation?
Answer: Infrared Light
- Deoxyhemoglobin absorbs more of this light and corresponds to 50% of saturation?
Answer: Red Light
- In the pulmonary artery the mixed venous blood’s PaO2 is ____ and SpO2 saturation is ____.
Answer: 40, 75.
- What is Hb P50 point?
Answer: SpO2 is 50% and the PaO2 is 27 %.
- What is the rough rule of PaO2 and SpO2?
Answer: PaO2: 40,50,60, for SpO2: 70,80,90
- If the SpO2 is at 95 % then the PaO2 is at ____%.
Answer: 75
During what procedure can a standard pulse oximetry not be used?
MRI; a dedicated MRI probe is needed.
- Which part of the body detects changes in the SpO2 pulse oximetry than the finger?
Answer: Ear
- Endobronchial intubation will usually go ___________ by pulse ox. In the absence of _____ disease or low _____.
Answer: undetected, lung, FiO2
- What can limit the pulse oximetry?
Answer: no pulse and low peripheral perfusion
- What will Carboxyhemoglobin (COhB) do to the pulse oximetry?
Answer: Carbon monoxide poisoning is viewed as wxyhemoglobin by the pulse ox. And shows a SpO2 of 100%, this is an overestimation of the true oxygenation.
- What is one way to distinguish a true SpO2 reading with carbon monoxide poisoning?
Answer: Co-oximeter.
- What is it called when Fe2 (ferrous) in Hb is oxidized to Fe3 (ferric) form and cannot transport O2?
Answer: Methemoglobin (MetHb)
- At what percent of Hemoglobin will you begin to signs of Methemoglobin?
Answer: 15 %
- What drugs cause methemoglobin?
Answer: nitrates, nitrites, sulfonamides, benzoncaine (Hurrican spray, nitroglycerine, nitroprusside.
- T/F: Methemoglobin will absorb equally at both wavelengths, be 1:1, and shows a SpO2 of 65% regardless of the true oxygen saturation.
Answer: False, the SpO2 will show 85%. (Everything else in the statement was true.)
- Methemoglobin is treated with ______ _____ or ____ ____.
Answer: Methylene blue, ascorbic acid.
- Does fetal hemoglobin and bilirubin affect pulse oximetry?
Answer: NO
T/F: EtCO2 is the gold standard for tracheal intubation.
Answer: True
- Capnography rapidly and reliably indicates __________ intubation, but does not reliably detect ________ intubation.
Answer: esophageal, endobronchial
