Pulmonary Flashcards

1
Q

Can esmolol be given to patients with asthma?

A

Yes, it has little effect on bronchial smooth muscle in low doses (non-specific beta blockers like metoprolol and labetolol should be avoided)

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2
Q

What is a normal V/Q ratio?

A

alveolar ventilation: 4L/min

pulmonary blood flor: 5L/min

V/Q ratio: 0.8

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3
Q

What are the ABG findings during an asthma attack?

A

always hypoxemia

early hypocarbia and respiratory alkalosis

late hypercarbia and respiratory acidosis (intubate)

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4
Q

Which pulmonary function test is independent of patient effort?

A

FEF25%-75%

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5
Q

What is normal tidal volume? Vital capacity? FRC? TLC?

A

tidal volume: 6-8 mL/kg

vital capacity: 10x tidal volume

FRC: 30-40 mL/kg

TLC: 5-6L in men, 4-5L in women

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6
Q

Which part of the flow-volume loop is affected by a variable extrathoracic obstruction? Intrathoracic?

A

Variable extrathoracic obstructions flatten the ispiratory limb

Variable intrathoracic obstruction flatten the expiratory limb

**fixed obstructions flatten both limbs**

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7
Q

What factors increase closing capacity?

A

increased age

small airway disease

smoking

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8
Q

How long should elective surgery be delayed for a URI?

A

controversial, 2 weeks after symptom resolution is reasonable

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9
Q

Who should get stress-dose steroids intra-operatively?

A

Patients with 2 weeks of systemic steroids over the past 6 months.

BUT

Reasonable to treat unexplained perioperative hypotension empirically

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10
Q

Should patients with severe asthma get pre-operative steroids?

A

a 5-day course of methyprednisolone is effective in reducing post-intubation bronchospasm

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11
Q

Should patients with asthma get IV lidocaine prior to intbuation?

A

No, it may cause paradoxical bronchospasm

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12
Q

Why shouldn’t nitrous oxide be given to patients with pulmonary HTN?

A

It can increase PVR

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13
Q

Which inhalational agents should be used for patients with reactive airway disease?

A

at > 1 MAC, sevoflurane is slightly superior to isoflurane as a bronchodilator

desflurane increases airway resistance and should not be used

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14
Q

Can succinylcholine be used in asthmatic patients?

A

Yes, the degree of histamine release is minimal and not associated with increased airway resistance

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15
Q

How do you calculate auto-PEEP on the ventilator?

A

airway pressure during expiratory hold - set PEEP

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16
Q

Describe the management of an acute increase in peak airway pressure intra-operatively.

A

increase depth of anesthesia

suction and check position of ETT

given beta agonists, ketamine, epinephrine

switch to an ICU vent (higher inspriatory pressures)

Heliox

V-V ECMO

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17
Q

What are the considerations for reversal of muscle relaxation in an asthmatic patient?

A

Neostigmine can cause bronchoconstriction

Try to avoid reversal or use higher doses of glycopyrrolate/atropine

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18
Q

What analgesic presents problems for asthmatic patients?

A

morphine - histamine release

NSAIDs - increased leukotrienes

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19
Q

Why does oxygen supplementation in patients with COPD lead to hypercarbia?

A

1) smaller tidal volumes
2) disruption of hypoxic pulmonary vasoconstriction

20
Q

Where should the pulse oximeter be placed during mediastinoscopy?

A

On the right hand, to detect compression of the innominate artery

21
Q

Where should the IV be placed during mediastinoscopy?

A

Upper extremity IVs are fine, but there should be a plan for lower extremity IV access in case of SVC hemorrhage

22
Q

What are the advantages and disadvantages of a bronchial blocker?

A

Advantages:

can be used in patients too small for a DLT

can be used through a single-lumen tube (difficult airway, no need for exchange at end of case)

DIsadvantages:

unable to suction through

unable to apply CPAP through

difficult to position and maintain position

tracheal occlusion if dislodged

23
Q

What are the wavelengths used for pulse oximetry?

A

660 nm: max absorption by deoxyhemoglobin

940 nm: max absorption by oxyhemoglobin

**Plethysmography allows sampling only arterial blood**

24
Q

What is the timing of hypoxic pulmonary vasoconstriction during one-lung ventilation?

A

begins in 15 minutes

completes in 2 hours

reverts to normal several hours after OLV

25
Q

What is the normal distribution of blood flow between R and L? Dependent and non-dependent? With one-lung ventilation?

A

baseline: 55% to R, 45% to L

in lateral decubitus position: 60% to dependent lung, 40% to non-dependent lung

with OLV: 80% to dependent lung, 20% to non-dependent lung

26
Q

How should ipsilateral shoulder pain be treated after lung resection?

A

NSAIDs effective

opioids ineffective

brachial plexus blocks possible, but may paralyze diaphragm

27
Q

What are the sequelae of aspiration?

A

obstruction

pneumonitis

pneumonia

28
Q

What amount/quality of fluid qualifies as aspiration?

A

25 mL

pH < 2.5

29
Q

What should NOT be done after aspiration?

A

NIPPV

lavage

steroids

antibiotics (not until evidence of infection)

30
Q

What conditions have the best evidence for use of NIPPV?

A

cardiogenic pulmonary edema

OSA

COPD

31
Q

What are the Berlin criteria for ARDS?

A

1) worsening respiratory symptoms
2) bilateral lung infiltrates not explained by cardiac causes
3) PaO2/FiO2 ratio:

mild 200-300

moderate 100-200

severe < 100

32
Q

What kinds of trauma are being avoided with ARDSnet ventilation strategies?

A

volutrauma

barotrauma

atelectrauma

33
Q

What are the principles of ARDSnet ventilation strategies?

A

low tidal volume: 6 mL/kg

Pplat < 30 mmHg

permissive hypercapnea

SaO2 > 88%

34
Q

What are the last resorts for severe ARDS?

A

prone positioning

inhaled nitric oxide

HFOV or APRV

V-V ECMO

35
Q

What are the principles of induction for patients undergoing lung transplant?

A

avoid abrupt withdrawal of sympathetic tone

prolonged pre-oxygenation time

volatile agents to promote bronchodilatation

36
Q

What are the considerations for ventilation in patients undergoing lung transplant?

A

left-sided DLT

avoid air-trapping with increased expiratory time

balance ventilation and venous return

toleration of hypercapnea

37
Q

What problems are associated with lateral positioning during lung transplant?

A

diminished venous return

compression of the dependent lung

elevated PA pressure

38
Q

What are the critical points of a lung transplant procedure?

A

induction

lateral positioning

commencement of one-lung ventilation

PA clamping

graft reperfusion

39
Q

How do you evaluate and treat cardiac function during PA clampling?

A

evaluate RV response on TEE

attempt pulmonary vasodilators

may require CPB

40
Q

What can cause hypotension after pulmonary graft reperfusion?

A

wash-out of vasodilating preservatives

coronary air embolus from incomplete de-airing

41
Q

What happens to PA pressure after pulmonary graft reperfusion?

A

it should fall

if it does not, you must reassess the anastomosis and consider eary graft dysfunction

42
Q

What is the alveolar gas equation?

A

PAO2 = FiO2 (Patm - pH2O) - PaCO2/0.8

Patm ~ 760 mmHg

pH2O ~ 47 mmHg

43
Q

What is the oxygen content equation?

A

CaO2 = (SaO2 x Hgb x 1.34) + (0.003 x PaO2)

** mL of O2 per 100 mL blood **

44
Q

What happens to PaCO2 during apneic oxygenation?

A

increases by 6 mmHg in the first minute and 3 mmHg in each subsequent minute

45
Q

What is the Winter’s formula?

A

Estimates the respiratory compensation for a metabolic acidosis:

expected PaCO2 = (1.5 x HCO3-) + 8

46
Q

How much does pH change based on PaCO2?

A

pH changes by 0.08 for every 10 mmHg change in PaCO2