Flashcards in Quiz 9 - One Lung Ventilation and Malignant Hyperthermia Deck (38):
During lung surgery the dependent lung is the lung that is down or up?
During lung surgery, which lung is nondependent?
the upper lung
During lung surgery, where do you want to avoid placing the axillary roll?
in the axilla. The roll should be placed along the upper chest.
Why should you restrict IVF during lung surgery?
Restrict IVF to basic maintenance to avoid gravity dependent fluid transudation to dependent lung and edema to the collapsed lung
When you are awake and in a lateral position, which lung is better perfused and ventilated?
The dependent lung
During surgery where a pt is in a lateral position, which lung will be better ventilated? Is this a problem?
The nondependent lung will be better ventilated but the dependent lung will be better perfused causing a VQ mismatch
Due to the V/Q mismatch during open pneumothorax surgery, a _______ to _____% right-left intrapulmonary shunt occurs.
Hypoxic Pulmonary Vasoconstriction can worsen a right-left shunt (T/F)
False, it will improve the V/Q mismatch by shunting blood from the nonventilated, nondependent lung to the dependent lung.
What factors can inhibit hypoxic pumonary vasoconstriction (HPV)?
Vasodilators (NTG, Nipride, Dobutamine, Ca channel blockers)
Should you reduce your tidal volume during one lung ventilation?
NO, keep the Vt around 10cc/kg
During apneic periods, how fast will the PCO2 incr3ease in the first minute and every minute after that? (if you are giving ample amount of O2)
It will rise 5mmHg in first minute and 3mmHg for each additional minute
If using apnea during surgery, what is the time limit of the surgery due to progressive resp acidosis?
Limited to 10-20 min
During one lung surgery where do you what to keep your FIO2 level?
During one lung ventilation, add ____ cmH2O CPAP to the nondependent lung and _____cm H2O PEEP to the dependent lung. Increase both slow
5 cm H20 for both
Which double lumen ETT is most commonly used for one lung ventilation, a left or right?
Left - easier to place since you don't have to worry about aligning an opening with the right upper lobe bronchus.
What are some common triggers for Malignant Hyperthermia?
Succinylcholine and inhalation agents.
Other possible triggers could be stress, muscle trauma, exercise and heat stroke.
What is the first sign of MH?
What is the most specific sign of MH?
Increasing ETCO2 (hypercapnea), also decrease SaO2 and SpO2
What are some other signs of MH?
Rigid muscles despite relaxants, dysrhythmias, tachypnea, cyanosis, sweating, unstable BP, mottled skin, trismus (masseter spasm), and more...
Who has a greater incidence of MH, children or adults?
Children (1:12,000) vs adults (1:40,000 with succs, 1:220,000 without succs)
Who is susceptible to MH?
persons with musculoskeletal issues, closely related family members of persons with known MH, Duchenne's muscular dystrophy, King-Denborough syndrome
What is the first thing you should do if you suspect MH during a case?
Stop all triggering agents then call for help
What is the doseage for Dantrolene during MH?
2.5mg/kg IV ASAP then repeat q 5 min up to 10mg/kg (mixed in sterile H2O)
During a case of MH, what else should you do/give besides Dantrolene?
Hyperventilate with 100% O2
Bicarb 1-2 meq/kg IV then check ABG
Start cooling measures (iced IV NS (not LR) 15cc/kg every 10min x 3 and if necessary do cold body cavity lavage, cooling blankets, ice bags
Why wouldn't you use LR during MH?
Due to the extra Calcium and Potassium
What is the dose for continued Dantrolene after initial dose and how long will you continue that dose?
Dantrolene 1mg/kg IV q 6hrs for 72hrs
Should you use Calcium Channel blockers for tachycardia during MH?
no because it can cause life-threatening hyperkalemia and myocardial depression
What is the mechanism of action for Dantrolene?
Interferes with muscle contraction by inhibiting Calcium release from the sarcoplasmic reticulum
Does Dantrolene work intracellularly or extracellularly?
works by intracellular dissociation of excitation-contraction coupling
Is Propofol a safe drug to use during a surgery on someone with a known history of MH?
Yes, along with other IV drugs like benzos, barbs, etomidate, narcs, local anesthetics, NONDEPOLARIZING MUSCLE RELAXANTS, N2O, Ketamine,
What is the GOLD STANDARD for diagnosing MH presurgery?
muscle biopsy with halthane-caffeine contracture test
What is King-Denborough syndrome?
myopathy, short stature, cryptorchidism, pectus carinatum, lumbar lordosis, kyphosis, unsusual facial characteristics
If someone has a prior uneventful general anesthetic, does that rule them out for having any other issues with MH in the future?
No, can undergo multiple uneventful episodes of anesthesia before developing MH
Does Trismus (masseter spasm) alone after succinylcholine mean MH?
no, can happen 1% of time using succs
In boys under 9yrs who develop sudden cardiac arrest after induction with succs and absence of hypoxia, should be treated for hyperkalemia or MH?
Hyperkalemia first since this is the most likely cause.
How quickly do people usually develop MH after exposure to trigger substances?
Usually within 1 hr
What is considered a "full" supply of Dantrolene to have on hand?