General Flashcards
OSA vs. OSH and Pickwickian syndrome
OSA - cessation of airflow >10s, 5+ times per hour
OSH - dec in airflow>50% for 10s, 15x /hour
O2 sat dec>4% in both
PS - chronic hypoventilation, BMI >30, PaCO2 >44
Systemic manifestations of OSA
Cardiac - HTN, LVH, pulm HTN
Pulm - inc V/Q mismatch, dec FRC, atelectasis
GI - stomach displaced upward, inc GERD
Renal - HTN nephropathy
Neuro - hypersomnolence, inc sensitivity to anesthetics
Respiratory parameters for extubation
Rate - 10-20
SaO2 - >95%
Vital capacity - 10ml/kg
Tv - > 5ml/kg
Precipitants of Sickle Cell Crisis
Hypothermia Hyperthermia Infection Anemia Acidosis Hypoxia Hypotension Stasis
Prevention = pain control, hydration, O2, Hct >30%, treating infection, HbAA >50%
Types of crises in SCD
Vaso-occlusive from microinfarcts Aplastic Splenic sequestration Hemolytic Acute chest syndrome (resp, fever, pain, hypoxia, infiltrates)
Treatment for acute chest syndrome
Supportive - mechanical ventilation
Serial ABGs and chest X-rays
Broad spectrum abx
Either simple transfusion or exchange transfusion if severe and needed to maintain hct >30%
How would you respond to hypotension
Place patient on 100% O2
Look at the monitors to rule out malignant arrthymias, hypoxia, hypercarbia and feel for a pulse
Assuming all of these are normal I would open the fluids and give a small dose of Neo
Treatment for airway fire
Call for help Stop flow of O2 Disconnect ETT from source of oxygen Extubate making sure entire ETT has been removed Bronch to examine for extent of injury
Post op care of airway fire
Resecure airway
Humidified O2
Steroids
Racemic epi
What things shift the Oxy-Hb curve to the left?
Alkalosis
Hypothermia
CO, Fetal Hb, MetHb
Dec 2,3 DPG
Parkland Forumla
4 x % BSA x kg
1/2 in first 8 hours
1/4 second 8 hours
1/4 in last 8 hours
Adequate PaO2
PaO2 = 5 x FiO2
So on 100% O2 should have 500mmHg
How does cocaine affect anesthetic management?
Labile BP, severe HTN, difficult access –> VF, seizures, MI
- Pre-induction a-line, 5 lead EKG
- Infusions of nitroprusside
- Large bore IVs
- Only use direct acting agents like Neo, exaggerated response to indirect
- Precautions against HIV, HCV
Sitting position, difficult airway wants regional only, what would you say?
Inadequate regional —> sedation or GA in known difficult airway under less than optimal conditions.
If still refusing, explain that would have no sedation and should block not work would proceed with awake intubation.
Induction for eye injury, trauma and potentially difficult airway
Goals are to rapidly and safely secure the airway to reduce the risk of aspiration after achieving adequate depth of anesthesia and NMB to avoid coughing, HTN all of which increase IOP and risk extrusion of contents.
RSI with Sux recognizing the transient increase in IOP minor compared to dramatic increase with coughing with inadequate intubating conditions. Pretreat with ND-NMB, lidocaine to dec potential of fasiculations
How would your anesthetic management be different for a patient taking lithium?
Toxicity - weakness, wide QRS AV block, hypotension
Avoid drugs that may lead to toxicity - thiazides, NSAIDs, ACE
Potentiates NMBD
Avoid ECT –> prolonged seizure, dysrhythmia, prolonged delirium
Med given just prior to clamping iliac vessels?
Heparin
Mannitol +/- furosemide after revascularization
Cause of hemolytic transfusion reaction
Anti-A or B IgM antibodies to RBC membranes—> complement mediated hemolysis
Pathogenesis of AIP
Deficiency in one of the enzymes of heme synthesis —> overproduction of porphyrins
Manifestation depends on specific pathway involved - severe abdominal pain, nausea, vomiting, CNS instability, weakness, paresis, rep failure
Cause of hemolytic transfusion reaction
Anti-A or B IgM antibodies to RBC membranes—> complement mediated hemolysis
Pathogenesis of AIP
Deficiency in one of the enzymes of heme synthesis —> overproduction of porphyrins
Manifestation depends on specific pathway involved - severe abdominal pain, nausea, vomiting, CNS instability, weakness, paresis, rep failure
Factors that lead to porphyria crisis
Fasting
Dehydration
Stress
Infection
Avoid methohexital, etomidate, ketorolac
Fill servo vaporizer with Iso, what happens?
Agent specific - concentration (volume %) dependent on vapor pressure of agent
Delivered concentration would be higher than expected
LIM alarm sounds, what would you do?
between 2-5 mA? = too many pieces plugged into circuit, unplug last thing
> 5mA = faulty piece of equipment - identify and remove
Describe the Post-Anesthetic Discharge Scoring System
Score 9 or higher to be discharged
- Vitals (0-2)
- within 20%, 20-40%, >40% - Ambulation (0-2)
- steady, assistance, dizziness - N/V (0-2)
- minimal, moderate (IV), continuous - Pain (0-2)
- PO meds, IV, not acceptable - Bleeding (0-2)
- minimal, 1-2 dressing changes, intervention required
How does ESWL work
sudden vaporization of water by energy source generates a pressure wave focused on the stone
When focused on areas of body tissue similar to water, shock wave travels through without significant dispersion of energy, avoiding injury to tissue
Considerations with morbid obesity
Dec FRC --> desaturation Hypoventilation, OSA DM HTN, LVH CAD DVT/PE
Monitoring - BP cuff bladder encircle 75% of arm
What happens with closing capacity in obese patients
Relationship with FRC worsened –> early airway closure and shunting
Your labs return with a normal PT and an elevated aPTT, what do you think?
This is consistent with either: vWD, hemophilia A (VIII), Hemophilia B (IX), lupus or low dose heparin
I would consults a hematologist
Order vWF activity, Factor VIII activity, Factor IX activity
The lab reports Factor VIII activity of 5%, would desmopressin be helpful?
DDAVP may be helpful in mild cases of hemophilia A (>5%) - it rapidly increases amount to Factor VIII and vWF
Given metoclopramide pre-op, PACU beings shaking, how would you treat?
Could be hypothermia, ensure normothermia and consider warming blanket or meperidine
Given metoclopramide - consider EPS –> give O2, assess resp status, give diphenhydramine
Would you allow morbidly obese patient to have case performed at an ASC?
Probably not
I would perform a H&P and determine extent and severity of coexisting disease including presence of OSA.
I would consider:
- type of procedure (no airway surgery, children <3)
- post-op opioid requirements
- capabilities of the ASC (DI equipment, transfer arrangements)
In this patient with HTN, asthma, obesity, DM for umbilical hernia, what pre-op labs would you require?
Given that this is a low risk procedure, I would only require a pregnancy test and serum glucose level.
How would you extubate this morbidly obese asthmatic patient who just had a bronchospasm?
Given these events I would prefer to extubate her under a deep plane of anesthesia to prevent any further bronchospasm.
However, given her obesity and risk for aspiration from GERD I would empty her stomach with an OG and be prepared to suction any gastric contents should they appear
How do you classify extent of burn injuries?
How is this different in children?
Head and neck - 9% Arms - 9% each Trunk anterior - 18% Trunk posterior - 18% Leg - 18% each
Head - 18% (subtract 1% for every year over age 1)
Legs 14% (add 1/2% to each lead fr every year over age 1)
At what point would you intubate a burn patient?
I would asses for hypoxemia, respiratory distress, stridor, hypercarbia, AMS, and extent of burns
I would immediately intubate anyone with these signs or symptoms or with burns full thickness >10% to reduce risk of further deterioration or progressive airway edema
How would you intubate a patient with 15% BSA burns who is coughing carbonaceous material?
This is consistent with a major burn and probable inhalation injury –> intubate immediately
Risk of DI (airway edema, C-collar), obstruction (3rd spacing, inhalation injury), aspiration –> GI ppx, 100% O2, topicalize airway –> awake fiberoptic
What are your concerns in a patient with chronic alcohol abuse?
Inc MAC Tolerance to medications Cognitive impairment, cerebral atrophy Peripheral neuropathy Cardiomyopathy Cirrhosis Hypoglycemia, thrombocytopenia, GI bleed Electrolyte abnormality Withdrawal
What lab work would you order for a diabetic patient?
It would depend on the case and severity of the disease from H&P (neuropathy, HTN, CAD)
I would look for signs of end-organ disease
- CBC
- CMP - BUN, Cr, K, Glucose
- EKG for silent ischemia
Patient will not allow you to attempt an IV despite reassurances it will not hurt, what will you do?
Take to OR
Have DI cart in the room + surgeon for possible trach
Small IM dose (3mg/kg) ketamine with goal of maintaining spontaneous respirations while obtaining IV
Obese, asthmatic, Down syndrome with submandibular abscess, large protruding tongue, drooling, uncooperative patient. What is your plan for induction?
Given respiratory distress and potential DI, abscess, Down syndrome would prefer an awake FOI or tracheostomy
Goals - secure airway while maintaining spontaneous ventilation, avoid hypoxia, and aspiration.
Unlikely to tolerate awake -> neck prepped, small doses of ketamine, inhalation induction with fiberoptic intubation
Unable to advance ETT in Down patient with fiberoptic scope
Could be compression 2/2 to abscess or subglottic stenosis.
Attempt to pass smaller ETT –> trach
During transport SpO2 falls, you note some leaking around the tracheostomy site and realize it has been dislodged. What will you do?
Send someone to get surgeon and DI cart
Quickly attempt replacement –> intubate from above
Plug trach site and attempt mask ventilation while transporting back to OR
How can you provide renal protection during aortic cross clamp?
Best = maintain adequate intravascular volume and hemodynamic stability.
Intermittent cross-clamping, diuretics, mannitol but little evidence medications improve outcome
Are renal protective strategies necessary when clamp is infrarenal?
Yes
Still have inc in renal vascular resistance and dec renal blood flow
How does aortic cross clamp inc risk for SC ischemia?
Cross clamp leads to hypoperfusion.
Anterior spinal cord vulnerable due to single blood supply.
SCPP = Aortic pressure - CSF.
Clamp causes cerebral hyperemia and inc CSF pressure + dec aortic pressure –> ischemia.
Reduced by avoiding hypotension, minimizing cross-clamp time, draining CSF, monitoring SSEPs and MEPs, utilizing a shunt
What mechanisms protect against delivery of a hypoxic mixture?
Fail safe alarm - sounds when pipeline O2 <30 PSI
O2 failure shut off valves - D/C other gases with drop in O2 pressure
Best = vigilance and O2 analyzer
Difference b/w Sevo and Des vaporizer?
Sevo = variable bypass, variable amount of gas is directed into vaporizing chamber where is mixes with gas before returning to carrier gas
Des - high vapor pressure and heat of vaporization requires a special vaporizer. Does NOT direct fresh gas flow. The reservoir is instead heated to create vapor pressure of 2atm –> pure Des is mixed with fresh gas flow.
Pathogenesis of SCD?
Hemoglobinopathy mutation on Cr 11 - substitution of Valine for Glutamic Acid in beta chain of Hb
In low O2 tension this HbS can polymerize –> deformed shape –> hemolysis, microvascular occlusion, ischemia
What are the comorbidities assoc with SCD?
Chronic hypoxia, anemia –>
- cardiomegaly
- CHF
- pulm HTN
- renal failure
- painful crises, acute chest syndrome
- retinopathy
- necrosis of femoral head
- asplenia
SCD patient Hct 21%, do they need exchange transfusion prior to surgery?
Probably not
I would aim for Hct of 30% which has been shown to be just as effective.
Exchange transfusion can require more transfusions and inc risk of transfusion-related complications
Patient undergoing TURP gets HTN and restless, what do you think is going on?
My differential would include: TURP syndrome Bladder perforation MI (given recent MI) Hypothermia Inadequate anesthesia
Therefore I would ensure adequate oxygenation, check a 12 lead EKG for ischemic changes, ask the surgeon to stop and evaluate for perforation, check serum Na and glucose levels
Signs and symptoms of TURP syndrome
AMS Restlessness Dyspnea Dec BP Seizures HypoNa
Signs and symptoms of bladder perforation
N/V Diaphoresis BP instability Bradycardia Abd/Shoulder pain
How does OSA affect your anesthetic management?
H&P to look for comorbid conditions
Increased sensitivity to sedatives - cautious
DI - have equipment in the room
Pre-O2 thoroughly - dec FRC
Multimodal pain regimen to dec opioid use
Extubate in head up position to optimize respiratory mechanics
CPAP available in PACU
Your resident administers propofol while performing an awake fiberoptic intubation so that the patent doesn’t move. The patient become apnea and starts to desaturate, what would you do?
Call for help Mask ventilate Attempt to awaken patient Attempt DL Place LMA Surgical airway
Do you need any special equipment while using a CO2 laser?
Flammable surgical drapes minimized Wet towels to cover face, neck and shoulders to absorb laser energy Eye protection for patient OR staff FiO2 as low as possible Laser safe ETT with saline filled cuffs Fire extinguisher Smoke evacuator Masks to prevent spread of virus (papilloma)
What precipitates acute chest syndrome?
Noninfectious etiologies
- fat embolism
- fluid overload
- hypoventilation
- PE
Or pneumonia
What nerves are you blocking to perform an awake fiberoptic intubation?
Maxillary branch of trigeminal (nose)
Glossopharyngeal
Vagus
- superior and recurrent laryngeal branches
Surgeon says patient is completely sensate over anterior deltoid. What is your response?
Anterior deltoid innervated by superficial cervical plexus which is not always blocked by interscalene
How would you test if your upper extremity block is working?
C5 - arm abduction, biceps flexion
C6 - elbow flexion, wrist extension
- sensory deltoid –> thumb
C7 - Elbow and finger extension
- sensory pointer and middle finger
C8/T1 - finger flexion, thumb abduction (ok sign)
How would you test to see if your lower extremity block is working?
Femoral (L2-4) - knee extension
Sciatic (L5-S1) - knee flexion
Peroneal (L4-S1) - foot eversion and dorsiflexion
- L4= big toe
Tibial (L5-S1) - foot inversions and plantar flexion
- S1 = little toe
Would you use albumin a burn patient?
No
Colloids worsen hypovolemia by leaking through capillaries into extracellular space –> in oncotic pressure further depleting intravascular volume
How do burns affect response to ND-NMBDs?
> 25% BSA –> need 3-5x normal doses
What are the STOP-BANG criteria?
- Do you Snore loudly?
- Do you often feel Tired during the day?
- Has anyone Observed you stop breathing?
- Do you have high blood Pressure?
- BMI >35
- Age >60
- Neck circumference >16”
- Gender: Male
Describe the modified aldrete scoring system
"ROCCA" Respiration - breathe deeply, coughs - dyspneic, shallow - apneic
Oxygenation
- > 92% room air
- 90% on O2
- < 90% on O2
Circulation
- BP +/- 20% baseline
- 20-50%
- > 50%
Consciousness
- awake
- arousable
- not responsive
Activity
- moves all extremities
- moves 2
- no movement
What is a phase 2 block and how would you manage it?
Large dose of sux (2-4mg/kg), repeated or gtt
Post-junctional membranes RE-polarized but not responding normally to Ach
Fade
Post-tetanic facilitation
Antagonizing with cholinesterase inhibitors is controversial –> wait until it resolves
What antibiotics would you use to treat this patients PNA? Assume gram positive cocci.
Get culture and sensitivity data
Azithromycin
Levofloxacin
Clinda - any gram -
If MDRO/MRSA etc
- Vanco/Zosyn
You notice inc etCO2 and then notice subcutaneous emphysema, how would you treat?
100% O2
Hyperventilate
D/C or dec insufflation
Evaluate for PTX
Would you use a regional anesthetic in a MG patient?
Regional can be used, however, I would prefer to do GA because
- MG patients have decreased ventilatory reserve
- Any T-berg position would likely make spontaneous ventilation more difficult
- Any weakness from block or anesthetic level could exacerbate ventilatory weakness.
- In the event of an ascending block causing respiratory weakness, emergent intubation could become necessary
I would weigh the risks and benefits of regional and its potential to affect respiratory muscles. I would use an amide local anesthetic.
How would induction with propofol in ESRD patient differ from healthy 20 year old?
Possible inc Vd and dec protein binding –> needing smaller volumes but likely not significant
How would you treat a venous air embolism in a laparoscopic procedure?
100% O2
Flood field with saline
Stop insufflation
Lower level of surgery/entry compared to heart (Reverse-T) to dec air entry from gravitational force
Epi or norepi gtt
Chest compression as part of ACLS to break up air and redistribute to smaller parts of pulmonary circulation (avoiding air lock)
Surgeon can’t pass cholangiogram catheter into CBD, no stone felt. Other cause?
Sphincter of Oddi spasm
Tx = naloxone vs glucagon
Morphine known to cause spasm, ? other opioids are any better
Pt had febrile response to haldol, are there any special precautions required for ECT treatment?
“Trigger-free” anesthetic is controversial with NMS.
Could avoid use of SUX
What are the acceptable levels of N2O and Sevo in the OR?
N2O = <25ppm
Iso/Sevo = <2ppm
25 air exchanges per hour
can measure with IR spectrophotometer
