Respiratory Flashcards

1
Q

Ddx for hypoxia and b/l chest infiltrates?

A
  • Aspiration pneumonitis
  • ARDS (can be 2/2 to anything…head trauma, fat embolism, aspiration)
    - Pulm manifestation of SIRS
    • Mech: Injury to capillary alveolar membrane –> can lead to permanent scarring and fibrosing alveolitis
  • Cardiogenic pulm edema
  • TRALI/TACO
  • Neurogenic pulm edema (can happen after any insult to CNS)
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2
Q

Periop resp complications associated with OSA? (4)

A
  • hypoxia
  • hypercarbia
  • resp depression
  • airway obstruction
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3
Q

How to dx OSA if no sleep study?

A

STOP BANG:
Snoring
Tiredness
Observed apnea
Pressure (BP)
BMI (>35)
Age >50
Neck (>40cm)
Gender (M)

1-2 of these: low risk, 3-4 high risk of OSA, 5-8 = high risk of mod-severe OSA

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4
Q

Overall periop complications associated w/obesity?

A

DMT2
Altered drug effects
PE
Metabolic syndrome
Stroke/CAD/NAFLD
Pt positioning
All of the apneas (OSA, postop apnea, OHS)

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5
Q

Things to consider when have an obese pt scheduled to have anesthesia at an outpt center?

A
  • Undiagnosed OSA
  • Other comorbidities and if optimized
  • Intra-op anesthesia (local/MAC, regional, GA)
  • Facility’s resources for emergency resp issues, transfer agreement, etc
  • Anticipated postop opiate requirement
  • Age
  • What kind of support to care for patient at home
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6
Q

Ddx for SOB especially in pt w/mediastinal mass?

A

1) Mass compression of airways (VQ mismatch, post-obstructive PNA)
2) Mass compression of great vessels (SVC, pulm art) or heart itself
3) Asthma/COPD/aspiration (pt also had GERD, asthma, and smoked)
4) Myasthenia gravis (thymoma most common ant med mass, and 30-65% of pts with thymomas develop MG)

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7
Q

Are PFTs helpful to obtain preop for a nonthoracic case? Why/why not?

A

No
- evidence suggests they are poor predictors of periop resp complications
- provide little additional info that can’t be obtained from CT
- don’t alter anesthetic plan

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8
Q

What would you have in the room for induction and airway management of pt w/ant med mass?

A
  • ALL kinds of ETTs! Reinforced, long ETTs/MLTs, endobronchial tubes
  • glide, fiber
    -surgeon in room w/rigid bronchoscope (can use to ID most patent mainstem bronchus, stent airway, jet ventilation), sternal saw (for worst case scenario!)
  • put pt in most comfy position
  • cannulate femoral arteries for ECMO just in case
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9
Q

Ddx and what to do if cannot ventilate pt w/o an ETT?

A
  • mass compression (if pt w/ant med mass), bronchospasm, obstruction, laryngospasm
  • place OPA, try to bag w/100% FiO2
  • auscultate chest
  • reposition if helpful for mass effect
  • DL to see if laryngospasm (if not, place ETT and try to ventilate. If still unable to, fiber thru to see if mucous plug or mass effect or bronchospasm and tx)
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10
Q

What is neg pressure pulm edema? S/s? Tx?

A
  • relief of airway obstruction iso high intrapleural pressures generated by vigorous inspiratory effort against obstructed airway –> inc transcapillary pressure gradient –> pulm edema formation
  • edema can occur w/in a few mins - 3 hrs! Coughing, tachypnea, hypoxia
  • maintaining airway patency, suppl O2, diuretics, mech ventilation PRN. Usually resolves quickly
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11
Q

How would you assess resp status in someone who is baseline hypoxic (~90%) and has a hx of smoking? Things you’d order preop?

A
  • H&P. Look for s/s of COPD: cough, sputum prod, freq of pulm infx/exacerbations, # of hospitalizations, effecacy of past txs?
  • CXR, PFTs (+/-…in this pt, if a case w/inc risk of postop pulm complications, maybe. Gives type and severity + if reversible component, baseline pulm fxn), serum albumin (<35 –> inc risk of postop pulm complications), ABG, +/- pulm consult
  • optimization if elective case: smoking cessation > 8wks, preop chest physio, bronchodilators, glucocorticoids, abx if e/o infx
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12
Q

Major thing to remember about interpreting PFTs?
What’s the cutoff for c/f extubation afterwards?

A
  • FEV1/FVC <70% = obstructive. <50% = severe
  • FEV1 and FVC <30% predicted = likely need for postop vent support
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13
Q

Benefits of smoking cessation

A
  • dec carboxyHb (improve O2 availability by shifting O2 dissociation curve to the R)
  • improved ciliary fxn
  • dec nicotine levels
  • dec airway hyperreactivity, sputum production, periop pulm complications
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14
Q

Conservative extubation criteria (likely in ICU) for pt you’re concerned about d/t pulm disease etc?

A
  • awake and cooperative and intact gag reflex
  • muscle relaxants fully reversed
  • VC > 10cc/kg, TV > 6cc/kg
  • NIF > 20
  • SPO2 > 90% on 40-50% FiO2 w/< 5 PEEP, or PaO2 > 60 w/FiO2 < 50%
  • PaCO2 < 50
  • RSBI < 100, or RR < 30
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15
Q

Explain how neurogenic pulmonary edema works?

A

Head/C-spine injury –> symp activation –> systemic vasoconstriction –> dec LV compliance –> inc LA pressure –> neurogenic pulm edema

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16
Q

Lots of things/systems etc that you should be thinking about with acute/chronic C-spine injury?

A
  • resp dysfxn (C3-5 phrenic n, C5-7 intercostal m)
  • hypoTN (neurogenic shock from loss of symp vasc tone)
  • pulm aspiration (NPO, GERD/paralytic ileus/impaired airway reflexes)
  • diff airway management (in line stabilization and inc risk aspiration)
  • thermal regulation (loss of vasoconstriction below)
  • arrhythmias
  • pt positioning injury (unstable C spine, lock of sensation below)

As time progressed, c/f:
- autonomic hyperreflexia
- hyperK
- PNA risk 2/2 impaired cough and secretion clearing
- inc risk DVT and PE

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17
Q

Good way to state why you’d want to wait to extubate patient who’s just undergone big surgery, like thoracic aneurysm repair

A
  • would not attempt extubation in OR d/t significant pulm disease,
  • deleterious effects of this type of surgery on pulm fxn (one lung ventilation, surgical manipulation of diaphragm and lungs, phrenic and RLN injury), and
  • potential for airway and pulm edema (significant fluid administration, inc capillary permeability a/w/ aortic X clamping)
18
Q

Assuming patient’s lung compliance was normal, what kind of vent mode would you place postop pt on in ICU?

A
  • SIMV: vent support + allowing pt to assist in WOB and exercise resp muscles until weaning was possible
  • if dec lung compliance, could conisder pressure control mode to maximize oxygenation and avoid vent associated lung injury
19
Q

What are some pulm studies to include in a pre-thoractomy assessment?

A
  • resp mechanics: FEV1, FVC, etc
  • lung parenchymal fxn: DLCO, PaO2, PaCO2
  • CV/P reserve: stair climbing, exercise SpO2, 6m walk test, VO2 max
  • calculate ppoFEV1% (predicted postop FEV1)…if < 40%, would order V/Q scan to assess contribution of lung to be resected. ppoFEV1 <40% are at high risk of RHF postop. Only need an echo if <40% and MACE was high
  • Best info to gather: ppoFEV1 (resp mechanics), DLCO (lung parenchymal fxn), and VO2 max (cardiopulm reserve)
20
Q

What are a couple of signs of chronic hypoxia? Like in a COPD pt

A
  • digital clubbing
  • High Hct (hypoxia can –> erythrocytosis)
  • pulm HTN, RHF
21
Q

How can you estimate a normal arterial PaO2 on RA for a patient?

A

102 - (age/3)

So, if have a 65yo, would be… 102 - (21.5) = 80.5

22
Q

Expected compensatory responses for acid/base disturbances

A
23
Q

How to explain why you’d place a L sided DLT for L pneumonectomy?

A
  • RUL bronchus’ proximity to carina (1-2.5cm) inc risk of RUL obstruction. LUL to carina = 5cm, so greater margin of safety
  • Could potentially suture tube at time of L bronchus resection, so need to w/d bronchial lumen of tube into trachea at this time
  • Could potentially disturb the bronchial stump by advancing DLT after closure of L bronchus, so need to be careful that this doesn’t inadvertently happen
  • Could be difficult to adequately advance L bronchial lumen into L main bronchus due to tumor location…in which case could place a R sided DLT or bronchial blocker
24
Q

Steps to take if pt hypoxic after initiation of OLV?

A
  • 100% FiO2
  • confirm proper DLT placement
  • ensure adequate perfusion (ECG, art line) and oxygen carrying capacity (Hb)
  • recruitment maneuvers
  • optimize PEEP to ventilated lung, CPAP to surgical side (can interfere w/their visualization)
  • re-inflate nondependent lung
  • discuss w/surgeon ability to ligate pulm art to eliminate shunt
  • consider PTX as possibility if pt w/COPD
25
Q

Criteria for extubation of post-thoractomy pts?

A
26
Q

Ddx for elevated CVP post-thoractomy?

A
  • RHF (top concern given COPD, poor ppoFEV1)
  • PE
  • MI, cardiac tamponade, cardiac herniation
  • arrhythmia
27
Q

Why are post-pneumonectomy pts at inc risk of developing SVTs? Most common SVT they develop?

A
  • underlying CV/R disease
  • inc RH afterload 2/2 puml vasculuar bed reduction
  • pain-induced stimulation of SNS
  • intraop cardiac manipulation
  • metabolic abnormalities
  • Afib! Controlled w/esmolol
28
Q

Possible co-existing disease if have OSA?

A
  • HTN, CAD, arrhythmias
  • pulm HTN, RHF
29
Q

Difference between:
- OSA
- OSH (obstructive sleep hypopnea syndrome)
- OHS (obesity-hypoventilation syndrome)
- Pickwickian syndrome

A

OSA:
- complete cessation of airflow for >10s, >5x/hr, >4% SpO2 decrease

OSH (obstructive sleep hypopnea syndrome):
- milder form of OSA - 50% dec in airflow for >10s, >15x/hr, >4% SpO2 dec

OHS (obesity-hypoventilation syndrome):
- 2/2 obesity, long term consequence of OSA. Defined: BMI >30, daytime hypercapnia (PaCO2 > 45), nocturnal hypoxia, polycythemia

Pickwickian syndrome:
- severe form of OHS where chronic hypovent –> pulm HTN and RHF

30
Q

What cardiac abnormalities would you expect in someone w/longstanding OSA?

A
  • all caused by chronic art hypoxemia and hypercarbia –> inc in cat levels
  • pulm HTN (also 2/2 hypoxic vasoconstriction) –> RVH and failure (cor pulmonale)
  • HTN (inc symp tone) –> if untreated, LVH and failure
  • arrhythmias –> angina, MI
  • polycythemia
31
Q

How to explain why no versed in obese/OSA pt?

A
  • even small doses of CNS depressants place these pts at risk for airway obstruction, hypovent, apnea
  • instead, their answer is reassurance, IDing his concerns, etc
32
Q

Explain why some drugs need to be dosed differently due to obesity?

A
  • lipophilic drugs (BDZs, opiates) have larger vol of distribution into body fat, so initial dosing on TBW is reasonable. But this also inc clearance time, so should dec doses for maintenance
  • hydrophilic vol of distribution unaffected, so should be IBW (NMBAs)
33
Q

Pt with a PAC develops significant hypoTN after episode of hypoxia. Ddx and steps you’d take to evaluate?

A
  • given timing, most likely: MI, arrhythmia, acute HF
  • could also be: excessive anesthesia, tension PTX (central line placement), anaphylaxis
  • evaluate EKG, ABP, PAP, CO, SVR, SaO2, ETCO2
  • d/c volatile agent to attenuate dec SVR, place pt in Tburg to improve preload, fluid bolus, inotrope/appropriate vasoactive drug depending on findings
34
Q

Ddx for PaCO2 of 54

A
  • nl inc during first 15-30 mins s/p peritoneal insufflation
  • inadequate ventilation
  • CO2 emphysema (insufflation)
  • capnothorax (CO2 into thorax through natural/iatrogenic communications
  • CO2 embolism
  • PTX (smoking hx, central line, hypervent)
  • aspiration –> V/Q mismatching –> hypercarbia
  • MH
35
Q

Anesthetic concerns for CF patient?

A
  • hypoxia (V/Q mismatch), bronchospasm, PTX (bullae formation), postop resp failure, heart failure (pulm HTN, cor pulmonale)
  • hepatic (coagulopathy d/t malabs of vit K, pseudocholinesterase def), pancreatic (DM), and GI (malabs –> lyte abnlties)
36
Q

Pathophys of CF?

A
  • inherited recessive dz
  • CF transmembrane conductance regulator (CTFR) is defective –> abnl movement of salt in and out of cells –> develops thick, viscous secretions –> luminal obstructions, glandular destruction in lungs, pancreas, liver, GI tract
  • mucous plugging, infl, chronic infx –> bronchiectasis, emphysema, hypoxemia, cor pulmonale, CM, hepatomegaly, resp failure
    -malnutrition, diabetes, coagulopathy (vit K dep), dec plasma cholinesterase
37
Q

What can reglan cause? How to treat it?

A

EPS!
- dyskinesias (repetitive body/facial movements like lip smacking, eye blinking)
- akathisia (extreme restlessness)
- dystonia (strong muscle contractions, esp the neck –> twisting of body and pain)

  • tx: suppl O2, assess resp/oxygenation, diphenhydramine or benztropine, d/c any antiemetic med
38
Q

A few causes for pulm edema in pregnant pt?

A
  • terbutaline (rare - don’t need to remember)
  • preE (inc vasc permeability)
  • PE (hypercoag and immobility)
  • previously unrecognized cardiac condition –> physio changes of preg –> inc intravascular volume and CO
39
Q

Examples of noncardiogenic pulm edema?

A
  • aspiration
  • neurogenic pulm edema
  • fluid overload
  • inhalational injury
  • ARDS
  • PE
  • allergic rxn
  • near drowning
  • adverse drug rxn
40
Q

Smoking cessation synopsis?

A

Recommend stop smoking even if it’s 2 days preop! Bc:
- recommendation to stop could lead to long term cessation, which is high priority
- even 2 days can dec carboxyHb levels and abolish nicotine’s stim effects on CV system
- some might argue that postop pulm complications don’t begin to dec until 4 weeks of cessation, and inc mucous clearance in first few days could worsen airway conditions and complicate management

41
Q

Pathophys of aspiration pneumonitis?

A
  • aspiration –> pneumonitis, PNA, ARDS
  • aspiration –> damage to surfactant-producing cells + pulm capillary endothelium –> atelectasis, pulm edema, bronchospasm, laryngospasm, shunt, dec pulm compliance, hypoxemia, tachypnea, tachycardia, inc PVR 2/2 HPV
  • intense infl response may then develop (asp pneumonitis) –> ARDS, fibrosing alveolitis
  • can develop PNA if aspirate contained oropharyngeal/gastric content
  • obstruction of lower airways by particulate matter can –> atelectasis and subsequent abscess formation