Misc Flashcards
BMI obesity classification
“Premedication” possibilities
- Reglan or antacid (Bicitra - citric acid) for aspiration
- Breathing tx (asthma)
- DVT ppx
- Abx
Would you give an obese pt versed?
“Would need to weigh risks/benefits with particular patient and see if there are any other measures they’d be okay with to decrease their anxiety (music, talking, etc) or possibility giving a bit of precedex instead - knowing that they are at higher risk of resp depression if have undiagnosed OSA. But also don’t want to cause increase in anxiety that could also lead to uncooperation/ineffective preoxygenation etc
How to calculate BMI?
To remember rough estimate…5’ 70kg person = BMI ~31 (5’ is ~ 150cm, which is 1.5m…1.5^2 = 2.25…70/2.25 = 31)
If height is in inches and weight in lbs, BMI = (lbs/in^2)*703
Remember 2.2lbs = 1kg
Fat embolism major/minor criteria and name
Gurd and Wilson:
petechiae
AMS
hypoxemia, pulm edema
unexplained thrombocytopenia, anemia
fat everywhere
tachycardia
fever
Tx of fat embolism?
- Give 100% FIO2
- Tx hypoTN and hypovol
- Give blood products PRN, keep ventilating
- Tell surgeon in case they’re able to shorten procedure
Explain MetHb and SpO2
- cyanosis typically doesn’t occur at a sat of 85%, more like 70%, so this can be a clue
- Traditional dual wave-length pulse oximetry is inaccurate in the setting of methemoglobinemia because these pulse oximeters measure the absorbance of light at two wavelengths - 660 and 940 nm. The ratio of this absorbance allows the distinction between oxyhemoglobin and deoxyhemoglobin, with the expressed percentage, or SpO2, indicating the measured amount of hemoglobin that is oxygenated. Methemoglobin has high absorbance at both of these wavelengths, leading to the interference that causes an inaccurate SpO2 reading. When the level of methemoglobin approaches 30-35%, the ratio of absorbance becomes 1.0. A ratio of absorbance (A660/A940) of 1.0 reads as a SpO2 of 85%.
Steps you’d take if your pt develops MetHb?
Most importantly, ID the oxidizing agent (benzocaine, prilocaine, etc) and stop it! Tissue hypoxia doesn’t occur until MetHb levels >30%. If levels were clinically significant though, would give 100% O2, consider exchange transfusion, and give methylene blue (or if G6PD def, ascorbic acid)
What is G6PD def? Symptoms, etc
- Sxs: Fatigue, cyanosis, jaundice, anemia, hypoTN, lumbar/abd pain, hemolysis (can have all the time, intermittently, or in presence of inc oxidants and free radicals like during illness/infection, certain meds, fava beans), hematuria, renal failure
Explain/draw out enzyme pathways relating to MetHb, methylene blue, and G6PD deficiency
- Basically, G6PD is needed to generate NADPH, which is needed for the methylene blue pathway to work, which converts ferric to ferrous heme
What does placing the pt in reverse T during induction do?
- Improves resp mechanics
- Dec risk of aspiration
- Facilitates venous drainage from intracranial compartment
What to do if poked with HIV pt? Transmission rate?
- Wash w/soap and water
- Contact employee health for blood draw
- rate w/perQ puncture = 0.3%
- will likely get postexposure ppx
- avoid transmissable activities until everything comes back
Myasthenia gravis sxs?
- dyspnea
- diplopia (dbl vision) –> blurred vision
- ptosis
- dysphagia
- difficulty chewing
- dysarthria (slurred speech)
- muscle weakness
How to dx myasthenia gravis?
- tensilon test (1st line. Edrophonium injx –> if muscle weakness improved with this AChE inhibitor, then might be MG)
- nerve stimulation
- AB immunoassays
“Bulbar sxs” - what are they, what sxs
- weakness in the muscles innervated by CNs V, VII, and IX-XII
- facial weakness, difficulty chewing, dysphagia, dysarthria
Risk factors (10) for CV periop complications for pts w/ant mediastinal mass?
- tracheal compression >50%
- ” “ >30% + bronchial compression
- stridor
- orthopnea
- cyanosis
- jugular distention
- SVC syndrome
- pericardial/pleural effusion
- combo obstructive + restrictive pattern on PFTs
Explain your overall method for evaluating severity of ant mediastinal mass preop?
Obviously H&P, focusing on:
- tracheal compression >50%
- “ “ >30% + bronchial compression
- stridor
- orthopnea
- cyanosis
- jugular distention
- SVC syndrome
- pericardial/pleural effusion
- combo obstructive + restrictive pattern on PFTs
…as well as:
Congenital effects seen with Down Syndrome pts that could effect airway?
- Macroglossia
- Atlanto-axial instability
- micrognathia
- subglottic stenosis
- could complicated mask ventilation, laryngoscopy, and ETT placement
2-3 major things to discuss with surgeon when about to perform anesthesia for a biopsy of a mass of some kind?
- what kind of biopsy is needed (e.g. for this mediastinal mass, are there any extrathoracic adenopathy, cervical/supraclav nodes available to do a much less invasive bx under LA instead of intrathoracic bx under GA)
- any chance of pt receiving chemo/radiation/steroids to decrease the size of the tumor prior to surgery if this would dec anesthetic risk, for example. However, rapid tumor lysis may affect accuracy of future histological dx so sometimes can’t
What can anticholinergics be used for in the OR?
- aspiration ppx (this seems like it was done in the past but no longer..they dec LEW tone and not shown to dec acidity/gastric volume - ASA no longer recommend)
- dec airway secretions
- dec airway hyperreactivity (asthma pt)
- obviously helps with bradycardia (esp if inducing w/inhaled sevo)
- random**: avoid anticholinergics in MG pts, as would lead to inc muscle weakness and bulbar sxs
How to eval someone for atlanto-axial instability?
- look at their previous anesthesia records/esp airway
- see if any neck radiographs-look for any subluxation (ant atlantodental interval > 4-5mm in any lat view)
- thorough H&P Re: s/s of cord compression (gait issues, paresthesias, fatigue when walking, and ask them to extend/flex neck to see if that elicits pain/motor/sensory deficits)
Pts with MG and Lambert Eaton…dosing of nondepols and depol agents?
- MG: will be RESISTANT to sux (not as many Rs available to create large depolarizing effect, so will need to give ~1.5x normal dose) and SENSITIVE to roc (the disease has already destroyed Rs so kind of already getting a head start on a nondepol mechanism)
- LE: lambs are SENSITIVE to both
Signs of cholinergic crisis?
- dyspnea
- constricted pupils
- weakness/muscle fasciculations
- brady
- salivation, N/V/abd cramps
- diarrhea, urinary freq/urgency
- diaphoresis
SEs of methylpred (or just high dose steroids in general)
- infx, impaired wound healing, immunosuppression, GI bleeding, resp compromise
- fluid retention, HTN, lyte imbalances, hyperglycemia,
**random side note: giving high dose steroids after acute spinal cord injury used to be recommended, but is no longer d/t lack of clinical benefit shown and all of the above named SEs