Notes
All body systems depend on adequate O 2
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Purpose of breathing: + O2 & - CO2
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Oxygenation
Includes... - Ventilation - Hgb & RBC transport |
- Gas exchange
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ATP production is vital for cell activity & life |
Cellular hypoxemia impairs the cell's energy production, disrupts cell function |
Acute lung tissue is at the alveolar-capillary membrane level |
Mechanics of Breathing
Concepts of airway resistance, lung compliance, opposing lung forces |
Inspiration: chest wall muscles contract, inc. intrapleural pressure = lung expands |
Expiration: lung deflates passively |
Blood flow through the lungs: - Bronchial - Pulmonary: highly vascular capill. network |
Pulse ox: measures O2 bound to Hgb (3% plasma, 97% Hgb) |
Smoking = carboxyHgb binds faster to Hgb |
Ventilation-Perfusion Ratios V/Q Scans: r/o pulmonary embolus |
Dead space: lung area has V/Q mismatch - Do not participate in gas exchange - Enough O 2
but not enough blood flow |
Shunt: blood bypasses alveoli w/o getting O2
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Silent unit: pt can have dead space & shunt |
Hypoxemia: not enough O2 in the blood |
Hypoxia: not enough O2 in the tissues |
Oxygen-Hemoglobin Dissociation Curve
Hgb saturation = oximetry
O2 partial pressure (mm Hg) = paO2
Don't just get SpO2 when acute, get ABG's!
- pH is important
- Aerobic anaerobic metabolism lactic acid buildup
Oximetry has a +/- 2 margin of error
Personal History Assessment
Smoking (#1) - how long, how much might not be ready to hear it but responsible to inform about risks & complications |
Allergies - year round, don't have to be allergic for things to affect breathing - Breathing in cold air is a very powerful irritant! (at least a cough) |
Drug use - ACEI (cough), amiodarone (cough), beta-blockers (compete for B2 sites) |
Travel - TB, outside country, soil |
SES - what's in home environment, pet hair, heating system in fall/winter |
Family Hx - genetics (recurr./chronic, acute) |
Occupation - if mask required, ventilation |
Respiratory Changes w/ Aging
Chest wall: stiffer, m/s issues dec. compliance |
Pharynx & larynx: muscles atrophy, airways lose cartilage, vocal cords start to slack |
Lungs: lose elasticity dec. compliance |
Alveoli: lose starting at 35yo but breathing not impacted unless chronic disease present |
Pulmonary vasculature: alveolar-capillary membrane thickens impairs gas exchange |
Ciliary action: move mucus & filter grunge (mucociliary exhalade) - Cilia paralyzed for 4 hr after every cigarette |
Subjective & Objective Data Assessment
SUBJECTIVE DATA |
Cough - cardinal symptom of respiratory disease (6-8 wk = chronic) |
Sputum - color? odor? changes? (normal = clear) |
CP - assoc. w/ other things (GI, MI, etc.) |
Dyspnea: length? onset? what helps? rate? |
OBJECTIVE DATA |
General appearance: visibly dyspneic? using accessory muscles (sternocleidomastoid, trapezius, intercostals)? position to breathe? |
Vital signs: (later) all affected w/ work of breathing |
Physical assessment: inspection, palpitation, percussion, auscultation - Always want extent to which you hear adventitous breath sounds |
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Diagnostic Evaluation
Laboratory Assessment - RBC (r/t Hgb transport) - Hgb - Sputum (sample for antibiotics, C&S) - ABG's (pH, CO 2 hypo-/hyperventilating; acidic/acidotic; bicarb.) |
Radiography |
CT scan |
Pulse ox |
Capnography |
PFT's |
Bronchoscopy |
Thoracentesis |
Lung biopsy |
V/Q scan |
Etc. |
Radiography
X-rays: air = black / everything else = white |
CXR - infiltrates, infusions, masses - Daily in ICU for changes |
CT Scan
Thin slices, more specific than radiography |
Often w/ contrast (more detailed) - Assess allergies (shellfish, iodine), kidney function |
Pulse Oximetry
Measure of O 2
attached to Hgb; SpO 2
or SaO 2
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Normal value: 95-100% |
Value affected by... - Poor peripheral perfusion/cold - Nail polish - Same arm as BP cuff - Applied correctly? |
Don't diagnose with value! |
Capnography
Measure of CO2 in exhaled air, which correlates w/ arterial CO2
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Normal value = 20-40 |
Now checking capnography w/ PCA pumps |
Pulmonary Function Tests (PFTs)
R/t volume and flow
Good way to track and trend where pts are
Bronchoscopy
Insert scope to examine upper & lower airway |
Invasive, need consent time-out! |
Therapeutic vs. diagnostic |
Labs: platelets (CBC), PT/INR (clotting) |
NPO 4-8 hr before |
Premedicate: sedation, topical to paralyze cords |
VS & Assessment: pre- & post-scope, infection, bleeding - May cause perforation or pneumothorax - Accessory muscles - Asymmetical expansion & breath sounds - Acutely dyspneic - Tachypneic - Hypertensive |
Thoracentesis
Therapeutic (remove fluid) vs. diagnostic |
Need consent, comfort pt |
Sterile procedure! |
Pre & Post: CXR, check puncture site, s/s of infection, VS, incentive spir. & deep breathe |
Assessment: pneumothorax, pain on affected side, mediastinal shift insert chest tube? |
Upright, leaning permits better access |
Lung Biopsy
Purpose: to obtain tissue sample for eval. |
Various approaches: - Transbronchial Bx (TBB) - Endobronchial Bx (EBB) - Mediastinoscopy - Open lung Bx (general anesthesia) |
Conscious sedation |
Fluoroscopy |
Pre: CT for depth and density of mass |
Post: gag reflex, VS (infection), pneumothorax, bleed, hemoptysis |
Ventilation-Perfusion (V/Q) Scan
Does ventilation match perfusion? - Mismatch = ventilated not always perfused |
Low/moderate/high probability for risk of pulmonary embolus |
Procedure: pt gets inhaled nucleotide |
Mixed Venous O2 Saturation (SVO2)
Get from pulmonary arterial line |
Purpose: to eval. O2 supply-demand balance |
Normal value = 60-80% |
Venous gas (60-80%) < arterial (80-100%) - Easier sample, less painful - What's going on at peripheral level |
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Pulmonary Embolism
A collection of matter that enters venous circulation and into the lungs |
DVT's is a big risk! |
Pathophysiology: |
1) Alveolar dead space inc. as blood shunted away |
2) Vasoactive & bronchoconstrictive substances released vasoconstriction dec. bood flow to lungs worsens PE |
3) Pulmonary vascular resistance inc. |
4) Pressure in pulmonary artery inc. |
5) R ventricle workload inc. |
6) CO dec. systemic blood pressure dec. |
7) Deoxygenated blood moves into arterial circulation hypoxia & hypoxemia |
Depends on SIZE of blood clot! |
PE Risk Factors
Anything causing venous stasis - vericose veins, inactivity (spinal cord/hip surgery), restrictive clothing, prolonged travel, obesity |
Hypercoagulable - obesity, trauma, cancer, factor deficiencies, birth control (estrogen) |
Venous endothelial disease - vericose veins, trauma, surgery, vascular vein disease |
Smoking - inc. fibrinogen = inc. viscosity |
Change in aging |
VIRCHOW'S TRIAD: (1) venous stasis (2) hypercoagulability (3) venous endothelial damage/injury |
80-90% come from venous |
PE Clinical Manifestations & Physical Assessment
RESPIRATORY |
SOB/dyspnea (worsening) - tachypneic, cyanotic, use of accessory muscles, cough, restless, panicky, confused |
CARDIAC |
Tachycardia |
Early/late HTN |
Pleuritic CP |
EKG changes |
S3 or S4
(pooling, R-sided workload inc.) |
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PE Management Goals
1. Improve gas exchange |
2. Improve lung perfusion |
3. Dec. risk for further clot formation |
4. Prevent complications |
Anti-Coagulation
Administered ASAP for therapeutic effect |
Length of time-variable |
Heparin - usually autely (unless massive) - -Kinases (antithrombolytic) - Bridge w/ Warfarin (Coumadin) - treat 3-6 months but depends on size & risk factors |
Other agents: - Enoxaparin (Lovenox) - Fondaparinux (Arixtra) |
Newer agents:
- Rivaroxaban (Xarelto)
- Dabigatran (Pradaxa)
- Apixaban (Eliquis)
- Endoxaban (Savaysa)
Pro: infrequent labs / Con: no quick reversal
PE Diagnostic Evaluation
Suggestive, not definitive |
Diagnosed w/ diagnostic tests, Sx, & labs |
Labs - CK, CRP, ESR, D-Dimer |
Radiology/CT, TEE (cardiac assess) |
V/Q scan - now more pulm. angiography |
D-Dimer: protein fragment active w/ clots
PE Treatment
O2 therapy - fix hypoxemia (vent/mask/NC) |
Anti-coagulation, Thrombolytic agents |
Surgery (embolectomy) & Filters (break up traveling clots; temporary or permanent) |
Ekos: endo catheter through blood vessels to deliver clot-busting med &/or break up clot |
Strategies to Prevent PE's
Early mobilization, Freq. position changes |
Active/passive ROM |
TEDs & SCDs |
Avoid tight clothes - esp. popliteal area |
Lifestyle changes - obesity/wt loss, smoking, birth control, activity, diet (salads), hydration, medic alert bracelets |
Anti-coagulation therapy - PT/INR, UFH |
Avoid valsalva maneuver laxatives |
Assessment/eval of peripheral circulation - color, temp., & sensation in extremities |
Bleeding precautions - electric razors, hold pressure, scissors & knives |
Heparin-Induced Thrombocytopenia (HIT): heparin antibodies develop bind to pH & activate thrombin ( develop clots)
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lanserj, 02:10 2 Aug 21
thanks
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