Random Flashcards
(117 cards)
Calculation of BP in different sites (example the arm cuff, and asking what’s the brain pressure?)
The difference in blood pressure at 2 different sites equals the height difference in cm (between cuff pressure and desired pressure sure) multiplied times the conversion factor 0.74.
TrueLearn Insight : A mnemonic to help remember which comes first (pressure or height) is “pH” or “pH 15 20”, where a pressure of 15 mmHg correlates to a height of 20 cm.
Pulse ox reading differences between CO vs methemoglobinmia?
The both would increase PaO2 with supplemental oxygen. However, in contrast, a patient with CO poisoning would most likely have a pulse-ox that is falsely elevated to 100% even while breathing room air since carboxyhemoglobin resembles oxyhemoglobin to a standard pulse oximeter. With methemoglobinmia the pulse ox would read 85-88%
What exacerbates acute intermittent porphyria?
P450 inducers Barbiturates BZDs Nifedipine Glucocorticoids Acute alcohol
These patient should be kept normothermic and well hydrated.
What electrolyte dearrangement must be corrected in anesthesia transplanted liver who is reviving massive blood transfusion?
Hypocalcimia
Citrate toxicity causes ionized hypocalcemia, manifested as hypotension and decreased pulse pressure, QT prolongation, and potential for arrhythmias.
Citrate toxicity causing severe hypocalcemia during liver transplantation is well documented and is manifested as hypotension, narrow pulse pressure, increased intraventricular end-diastolic pressure, and increased central venous pressure
What anti-depressant medication would be relative C/I to use methylene blue and why?
SSRI/SNRI or MaO inhibitors
Methylene blue is a MAO-A inhibitor and may cause serotonin syndrome in patients taking antidepressants. Suggestive symptoms include postoperative delirium and postoperative fever. Treatment is mostly supportive although cyproheptadine, a serotonin receptor antagonist, can be attempted.
what medications used to prevent epistaxis in nasal intubation? Local anesthetic is a choice?
vasoconstrictors such as oxymetazoline and phenylephrine
Lidocaine ointment is helpful in treating the pain of a nasotracheal intubation as well as functioning as a lubricant, particularly in awake intubations. however, does not prevent epistaxis. The only local anesthetic that would be useful for reducing epistaxis in this setting would be cocaine but it carries the risk of inducing arrhythmias.
Airway edema classified to subglottic vs supraglotic, what are the causes of either?
Supraglottic edema most often occurs following surgical instrumentation, secondary to impaired venous drainage (head down or prone position), the formation of a hematoma, excessive fluid administration, or due to coexisting conditions (preeclampsia/eclampsia, angioedema).
Subglottic edema most often occurs following traumatic intubation attempts or due to damage from the endotracheal tube (prolonged intubation, excessive cuff pressure, tight-fitting tube, patient bucking on the ETT).
Subglottic edema is much more common in children due to the smaller diameter of their airway.
Time expected to see post-extubation laryngeal edema ?
usually presents within 30-60 minutes of extubation as stridor although it can present up to 6 hours post-extubation.
Mgmt of post-extubation laryngeal edema?
1) 100% oxygen + head elevation to help improve venous drainage
2) asses for emergent re-intubation
3) nebulized racemic epinephrine
4) Heliox.
Steroids remain controversial and need several hours for effect.
Hoe nebolizer epi and heliox benefits in laryngeal edema?
- nebulized racemic epinephrine: alpha-adrenergic receptor stimulation in the airway resulting in mucosal vasoconstriction, causing a decrease in the amount of fluid present in the airway. It will also cause beta-adrenergic stimulation in the bronchial tissue resulting in bronchodilation, which will not alleviate the edema but can help any component of bronchoconstriction present)
- Heliox: ( it develops less resistance “because of its light density” when passing through the stenosis/edema resulting in less patient effort needed to get the same volume of gas.
RF of pulmonary artery rupture during PAC placement?
hypothermia (it increases catheter stiffness), anticoagulation, old age, and pulmonary hypertension
Compliacations of pulmonary artery placement (PAC)?
arrhythmia, valve damage, infection, PA rupture or infarction, thromboembolism, endocardial damage and misinterpretation of data
Interestingly the risk of endocarditis increase two-fold with use of non-heparin coated PACs.
stimulation of bronchoconstriction via 3 mechanisms?
- Main by parasympathetic nervous system (muscurinic receprots) via the vagus nerve. “ hypoxia & HTN can stimulate vagus nerve through carotid sinue/body to central nucleus ambiguous)
- Alpha receptor stimulation
- Excitation of NANC neurons by substence P & neurokinin A
Most common cause of perioperative retinal arterial occlusion is ?
Improper patient positioning resulting in external compression of the eye.
Postop visual loss due to ischemia of —– optic in cardiac vs spine surgeries?
Cardiac procedures, anterior ischemic optic neuropathy while spine surgery in the prone position, posterior ischemic optic neuropathy seems to be the predominant cause.
An easy way to remember ION would be the location of the surgery predicts the type – posterior spine surgeries = posterior ION and anterior cardiac procedures = anterior ION.
cardiac cases, related to emboli, thrombotic events, ischemic reasons, or even due to oncotic pressure changes.
In spine surgery the risk seems to be related to ischemia and/or patient position.
What pressure changes to PIP & Pplateau with Airway Resistance? DDX?
Increased PIP, Unchanged Pplateau
- Airway compression
- Bronchospasm
- Foreign body
- Kinked endotracheal tube
- Mucus plug
- Secretions
What pressure changes to PIP & Pplateau with Pulmonary Compliance (Elastic Resistance)? DDX?
Both increase( Increased PIP, Increased Pplateau)
- Abdominal insufflation
- Ascites
- Intrinsic lung disease
- Obesity
- Pulmonary edema
- Tension pneumothorax
- Trendelenburg position?
What is the initial compensation mechanism for acute respiratory acidosis ?
Increase plasma Bicab through plasma protein buffering (Hgb in RBC CO2 reacts with H2O to produce HCO3 and hydrogen, which this bicarbonate will exchange with CI to dump it in blood and raise blood HCO3)
Then urinary excretion of CI to reabsorb HCO3 happens later hours-days.
Will you have aspiration pox in asymptotic hiatal hernia repair?
Yes the asymptomatic and symptomatic at risk for aspiration even if no GERD sx because of esophagus dysfunction.
correcting high INR with Vit K?
No bleeding + INR <5 + elective then withholding warfarin for several days warfarin (1/2 t is 2-4 days).
No bleeding + INR >5 + surgery > 24 hrs then give Vit K
Bleeding, or INT> 10-> high dose Vit k (5-10 mg)
How do you correct high INR for urgent/emergent cases or active bleeding?
PCC (prothrombin complex concentrates) + Vit K
2 form of PCC; 4 factors (1972) and 3 factors (192) which factor 7 should be supplemented
S/E TRALI, and transfusion associated circulatory overload.
Ventilation goals in bronchipleural fistula?
End expiratory pressure
Short inspiration time
Low TV
Low RR
Spontaneous ventilation preferred over PPV.
Lung isolation decreases pressure and volume ( the theory of its benefit, ventilating both lungs may cause barotrauma and voluteuma to healthy lung since higher pressure needed to overcome through the fistula teak)
Mgmt of bronchopleural fistula?
Lung isolation with double lumen.
High frequency jet ventilation (delivers small TV under high pressure) but this causes hyperinflation and HD instability
If all falls then ECMO
Post op A-fib risks?
- cardiac/thoracic surgeries also large abdomen/vascular procedures
- present cardiac or Lung dis (HTN, valvular, copd/asthma …)
- intraop volume status (hypo triggers catecholamines from decreased i2 delivery, and increased catecholamines triggers AF) (hypervolemia also triggers AF through atreual mechanical stretch)