Ex2 Respiratory Dx Flashcards
75% of inspiration consists of
active contraction of diaphragm
25% of inspiration consists of
external intercostal muscles
expiration occurs as a result of
passive recoil of ribcage
forced expiration uses
internal intercostals/abdominal muscles
95% of URIs are
infective nasopharyngitis
safe to give anesthesia after URI after ____
4 weeks post-URI
**6w+ for reactive airways
Elective surgery 2 weeks after URI - proceed, postpone, cancel?
Cancel - reschedule in 2 weeks
Effect of GA on URI
decreases tracheal mucociliary flow/pulm bactericidal activity
PPV may force infxn deeper
immune response altered d/t surgery
intrinsic lung dx
-characteristics
- cause either:
1. inflammation/scarring of lung tx
2. fill air spaces w/ exudate/debris
intrinsic lung dx - examples
asthma, COPD
extrinsic lung dx
-characteristics
chest wall, pleura, resp muscles = disordered
–> cause lung restriction + ventilatory dysfunction
Asthma is more common in
Females > males
asthma is characterized by
- chronic inflammation
- reversible expiratory airflow obstruction
- bronchial hyperreactivity
asthma alternative explanation
abnormal autonomic regulation of neural fxn imbalance between bronchoconstrictor/dilator neural imput
FEV1
Volume of air that can be forcefully exhaled in 1 second
FVC
max amount of air that can be expelled after deep inhalation
normal M/F FVC
M = 4.8L F = 3.7L
FEV1/FVC
75-80%
direct measures of severity of asthma
FEV1
MMEF
MMEF
Forced expiratory flow at 25-75% of vital capacity (FEF 24-75%)
-measurement of flow thru midpoint of forced expiration
MVV
max voluntary ventilation
-measured over 15 seconds
Normal MVV
F: 80-120 L/min
M: 140-180 L/min
flow volume loop - asthma
downward scooping of exp.l limb (ice cream cone with scoop missing)
-Increased total lung capacity
Asthma: how severe?
FEV1 65-80%
mild asymptomatic
Asthma: how severe?
FEV1 50-64%
moderate
Asthma: how severe?
FEV1 35-49%
marked
Asthma: how severe?
FEV1 < 35%
severe
Asthma ABG
hypocarbia
respiratory alkalosis
CXR/ECG findings: asthma
CXR: hyperinflation
ECG: RH strain, irritability
When is PaO2 abnormal in asthma?
Marked + severe
< 60
FEV1 < 80%
obstructive airway disease
asthma tx
- controllers
2. relievers
Asthma controllers
-modify airway environment so that acute narrowing occurs less
-take longer to work
*corticosteroids (beclamethasone, fluticasone, budesonide)
*Cromolyn
*Leukotriene modifiers (Singulair/montelukast), salmeterol
Methylxantines (theophylline)
Asthma Relievers
rescue agents
- beta agonists (albuterol, metaproterenol)
- anticholinergics (ipratropium, atropine, glycopyrrolate)
Asthmatic may become hypercarbic if
impending fatigue + respiratory failure
status asthmaticus tx
- continuous inhaled B-agonist
- IV corticosteroids
- Magnesium, leukotriene inhibitors, terbutaline, epi
Epi dosage - status asthmaticus
SubQ 0.4mL of 1:1000
Terbutaline dosage - status asthmaticus
SubQ 0.25 mg
q15-30m
max dose 0.5mg in 4h
indicative of risk factors peri-op in asthma patients
Decreased FEV1
or FVC < 70%
+
FEV1/FVC < 65%
Major elective surgery should be postponed if
+ wheezing
Peak expiratory flow < 80% or less than personal best
VA choice for asthma
Sevoflurane
How to prevent auto-PEEP in asthma
I:E from 1:2 to 1:3 or 1:4
Best anesthetic for asthma
regional
*if GA: LMA > ETT
LMA risk: less control over expiratory phase
DOC for asthma induction/GA
- propofol
2. ketamine
After induction with IV agent, what other Rx (asthma)?
Ventilation with VA (Sevo)
+ Lido IV
+ opioids (Remifentanil)
Remifentanil infusion
0.05 - 0.1 mcg/kg/min
COPD is characterized by
- progressive airflow limitation NOT fully reversible
- expiratory flow obstruction
COPD - primary ventilatory drive
Chronic hypercarbia blunts drive; dependent on Oxygen
Risk factors - COPD
#1- smoking resp infxn, occupational exposure, genetic factors (antitrypsin-1 deficiency)
S/S COPD
hallmark - chronic productive cough + progressive exercise limitation
PFT - COPD
Decreased:
FEV1, FEF25-75%, ERV
Increased: FRC, RV (air trapping)
Treatment of COPD
Smoking cessation***
short term: increased sputum production
long term: O2 therapy
O2 therapy - COPD
Supplementation if:
PaO2 < 55mmHg
Hct > 55%
or evidence of cor pulmonale
Goal in O2 therapy for COPD
PaO2 60-80 mmHg
Rx therapy - COPD
B2 agonists, corticosteroids, diuretics
Predictive of post op pulmonary complications
smoking, diffuse wheezing, productive cough
> 60 y/o, COPD
emergency surgery
surgery specific: thoracic, head/neck, neuro, vasc/aortic aneurysm surgery
anes. duration > 2.5h
GA
Albumin < 3.5 g/dL
PFTs useful for ____ (COPD)
thoracic surgery
Preoperatively - COPD pt to reduce risk can do____
clear bacterial infxn
smoking cessation
tx bronchospasm
Regional preferred for COPD patients if ____
do not require above T6 (ventilatory dysfunction)
Ventilation of COPD
Low RR, TV 6-8mL/kg, slow inspiratory flow rate
*Air trapping: decreased recoil leads to retained air that should be exhaled
detection of air trapping
- capnography upslope
- exp flow rate does not reach 0
- PEEP develops/increases
- BP falls as PEEP increases
bronchiectasis
localized, irreversible dilation of a bronchus
-d/t infxn
s/s bronchiectasis
productive cough, large amounts of sputum, clubbing of fingers
CF - clinical manifestations
cough, purulent sputum production, exertional dyspnea
diagnosis: CF
Sweat test: Sweat Cl > 80 mEq/L
Tracheal Stenosis - symptomatic when?
trachea < 5 cm
Restrictive Lung Disease: PFTs show
Decreased lung volume, compliance, with preservation of expiratory flow rates
Decreased FRC, FEV1
Normal/increased FEV1/FVC
Acute intrinsic restrictive lung disease
pulmonary edema atelectasis ARDs Aspiration Neurogenic problems
Chronic intrinsic restrictive lung disease
Interstitial lung disease - fibrosis
-sarcoidosis, hypersensitivity pneumonitis, eosinophilic granuloma, lymphangioleiomyomatosis
Chronic extrinsic restrictive lung disease
chest wall, pleura, mediastinum
-scoliosis, pneumothorax, mediastinal mass
muscular dystrophy, guillain-barre, myasthenia gravis
spinal cord transection (at or below C5)
Pt presents to elective surgery with pulm edema - proceed?
Postpone + treat symptoms
- all acute restrictive disease
- i.e. drain large pleural effusion, persistent hypoxemia
intra-op management of pulmonary edema
Lower TV
Higher RR
goal: end insp plateau pressure < 30
Consider sending to ICU on vent
Interstitial Lung disease
Chronic intrinsic lung disease
-pulm fibrosis: loss of pulm vasculature, + pHTN, cor pulmonale, dyspnea, tachypnea
Preoperative management: chronic intrinsic restrictive lung disease
Infection: treat
Secretions: clear
smoking cessation
indicative of severe pulmonary dysfxn (chronic restrictive dx)
Vital capacity < 15 mL/kg
Intraop considerations - chronic restrictive lung dx
*use ACPC Hypoxemia + normocarbia apneic periods not tolerated GA, supine position, controlled ventilation=decreased FRC **VA uptake = faster* lower PIP (prevent barotrauma)
characteristic of extrinsic restrictive disease
most often d/t disorder of thoracic cage
lungs compressed, volumes reduced
increased WOB
Mediastinal mass: what should be done prior to anesthesia?
CT
Acute/severe condition - chronic extrinsic restrictive lung disease; elective surgery ?
postpone
*if necessary surgery: optimize patient preop
Pre-op optimization for lung disease
Rx: stress dose steroids, bronchodilators, antbx, diuretics
O2: supplemental, PEEP, vent
Intvn: drain pleural effusions/ascites, NGT/OGT for decompression, pulm toilet, smoking cessation
Patients at increased risk for periop pulm complications
> 60 y/o
ASA physical class II+
Functionally dependent
Procedures that increase risk of periop pulm complications
GA
>2.5h
emergency surgery
type of surgery
Acute respiratory failure: dx
PaO2 < 60 mmHg despite O2 supplementation
(-) R-L cardiac shunt
Increased PaCO2, decreased pH
Chronic resp failure: dx
Increased PaCO2
normal pH
ARDS characterized by
ALI (+ inflammation)
+ arterial hypoxemia
mortality rate: ARDs
50%
Phases of ARDS
- exudative (7d)
- Proliferative (8-21d)
- Fibrotic (After 3w)
Exudative phase - ARDS
high permeability pulm edema
proliferative phase - ARDS
interstitial inflammation
fibrotic phase - ARDS
fibrosis
Single most important factor for developing VAP
tracheal intubation
ARDS Treatment
ACPC
TV 6-8mL/kg
PEEP if FiO2 > 50%
Maintain UO > 0.5 mL/kg/hr
PE - s/s
- acute dyspnea
- tachypnea
- pleuritic chest pain
- rales
Pohlmans sign
calf pain (DVT)
PE - diagnosis
spiral CT
*gold standard but invasive/$$$ - pulm arteriography
EtCO2: PE
sharp + sudden decrease
PE Tx
- anticoag: heparin gtt
- inferior vena cava filter
- thrombolytic therapy: if unstable
- HD support: inotropic
- analgesia
- surgical embolectomy - for severe, refractory cases
Anesthetic management: PE
Cardiac inotrope/pulm dilator: milrinone
Fat embolism s/s
12-72h post long bone fx (tibia/femur)
Hypoxemia, Mental confusion, petechiae (neck, shoulders/chest)
Treatment: fat embolism
management of ARDS, immobilization of long bone fracture, corticosteroids