NotesAll body systems depend on adequate O2 | Purpose of breathing: + O2 & - CO2 |
OxygenationIncludes...
- Ventilation
- Hgb & RBC transport |
- Gas exchange
| 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 BreathingConcepts 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 O2 but not enough blood flow | Shunt: blood bypasses alveoli w/o getting O2 | 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 CurveHgb 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 AssessmentSmoking (#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/ AgingChest 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 AssessmentSUBJECTIVE 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 |
| | Diagnostic EvaluationLaboratory Assessment
- RBC (r/t Hgb transport)
- Hgb
- Sputum (sample for antibiotics, C&S)
- ABG's (pH, CO2 hypo-/hyperventilating; acidic/acidotic; bicarb.) | Radiography | CT scan | Pulse ox | Capnography | PFT's | Bronchoscopy | Thoracentesis | Lung biopsy | V/Q scan | Etc. |
RadiographyX-rays: air = black / everything else = white | CXR - infiltrates, infusions, masses
- Daily in ICU for changes |
CT ScanThin slices, more specific than radiography | Often w/ contrast (more detailed)
- Assess allergies (shellfish, iodine), kidney function |
Pulse OximetryMeasure of O2 attached to Hgb; SpO2 or SaO2 | 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! |
CapnographyMeasure of CO2 in exhaled air, which correlates w/ arterial CO2 | 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 BronchoscopyInsert 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 |
ThoracentesisTherapeutic (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 BiopsyPurpose: 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) ScanDoes 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 |
| | Pulmonary EmbolismA 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 FactorsAnything 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 AssessmentRESPIRATORY | 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.) | paCO2 inc. = acidotic |
PE Management Goals1. Improve gas exchange | 2. Improve lung perfusion | 3. Dec. risk for further clot formation | 4. Prevent complications |
Anti-CoagulationAdministered 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 EvaluationSuggestive, 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 TreatmentO2 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'sEarly 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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