Pulm Flashcards
5 lung volumes and capacities
what is the closing capacity. What increases it
What is FRC? Why is low FRC bad
CC is the volume at which distal airways without cartilaginous support begin to close with a forced expiratory manuver. Sum of RV and CV
CV volume at above residual volume at which distal airways close
increasing closing capacity is ACLS-S: Age, Chronic bronchitis, LV failure, Smoking, Surgery
FRC is volume left in lung after normal breath or TV/. reduces amount of oxygen available if apnea or hypovent occur. can cause hypoxemia
decresse FRC
Pregnancy ascites, neonatal, GA, obesity, supine surgery
absorption atelectasis
PANGOS
How would you assess pts COPD
- focused hx and physical:
- cough, dyspnea, ETT, freq pulm infections, mucus, orthopnea,
hospitalizations, meds (compliance, effectiveness)
- PE: vitals(sat, RR) cyanosis, clubbing (chronic hypoxia), signs resp distress use of assessory muscles, nasal flaring, listed to lungs,
- look for signs cor pulmonale: JVD, hepatomegaly, edema
- CBC: erythrocytosis,
CXR (hyperinflation or scarring): rule out acute process and serve as baseline for periopcourse
EKG (RVH),
ABG (hypoxia hypercarbia), electrolytes: met alkalosis to compensate for
Preop goals for COPD
periop goals
- determine type, severity, course
- optimize management: smoking cessation, treating infxn, bronchodilators, pulm toliet
periop goals
- minimize airflow obstruction
- clear secretions
- avoid preciptants of bronchospasm
- adequate pain control
What Fev1 is predictive off failing extubation and post op resp complication
What causes low DCLO
<50
destruction of pulm capillaries, low CO and anemia
predictors of post op pulm dysfxn
- preexisting pulm disease
- upper abdominal/throacic surgery
- smoking
- obesity
- advanced age >60
- prolonged GA
Benefits of epidural in COPD pts
- lower risk of pulm complications 2/2 decrease splinting, better cough, and earlier ambulation
- decrease in DVT
- superior blunting of stress response
- superior pain control
How would you ventilate a pt with COPD?
- slow RR with prolonged expiratory time to reduce air trapping. (COPD involves increased airway resistance that impede exhalation. delayed upstoke CO2 suggest incomplete emptying (consistent w obstruction)
- if bullous dz avoid nitrous, and min peak airway pressure and use PEEP cautiously to avoid rupture
- humdifiy gases to help preserve mucociliary fxn and ability to clear secretions
- ventilation should be targeted to maintain baseline. if aim for normocapnia, in chronic CO2 retainer, may end up w alkalosis which can lead to L shift oygen hemoglobin diss curve
How to reduce chance of post op resp complication
- ensure pai control to limit splinting (better the sooner the pt can ambulate, cough, take deep breath)
- ensure IS, and chest physiotherpay
- continue bronchodilators expectorants etc
- avoid excess fluids to min pulm edema
Why left side DLT preferred
How to confirm position L DLT
When would you place R DLT
R side closer to carina and variably located RUL, more risk of RUL occlusion
- inflate tracheal cuff should have b/l BS (ensures endotracheal intubation)
- inflate bronchial cuff, clamp tracheal. should have L side only.(confirms L sided endobronchial intubation
- If hear b/L DLT is out too far
- If hear right side: DLT wrong side (ensures tracheal balloon at carina - inflate tracheal clamp bronchial: right side only
- confirm w fiberoptic
When lesion at carina or L broncus makes L placement difficult
How to avoid broncospasm in asthmatic pt
- Preop: consider delaying URI or lower resp tract infection, premed w inhaled anticholinergic or B2 agonist
- consider regional
- If GA:
minimize airway stimulation: LMA, mask
GETA: IV lidocaine prop opioid bf airway stim, consider sevo, ketamine
- avoid B2 blockers or histamine releasing drugs (meperidine, morphine, mivacuriam)
- reversal: use adequate dose glyco
- extubate deep or with good level pain control
tx of acute broncospasm
- 100% Oxygen, hand ventilate, listen for breath sounds, inspect all monitors
- deepen anesthesia (prop, sevo, ketamine), B2 agonists (inhaler, epi), muscle relaxant if pt breathing against vent
- consider increasing expiratory time, higher inspiratory flow rate allow or rapid attainment of set TV (ICU vent)
- extubate and mask vent
Factors that inhibit HPV and increase blood flow to nondependent lung
- vasodilators and inhaled anesthetcs decrease nondependent HPV (SNP, NTG, dobutamine, CCB, B2 agonist, glucagon
- vasoconstrictors increase dependent lung PVR (epi, dopamine, phenypehrine
- inhaled agents
- Co2: hypocapnea may dilate nondependent lung; hypercapnea augments vasoconstriction dependent lung
- high airway pressures PEEP and inspiratory pressures may constrict vessels in depend lung (mechanical compression)
Absolute indications for DLR
- lung isolate to prevent spillage of infection, blood
- unilateral BPL (alevolar proteinosis
- differential ventilation (broncopleura fistuka, surgical opening of airway, tracheobroncheal tree disruption
- VATS
Alternatives to DLT
pros and cons
- endobronchial intubation w SLT
- bronchial blocker
- inability to suction/ventilate isolated lung, loss of seal can result in contamination of CL side, slippage into trachea can result in airway obstruction - univent tube
- can provide CPAP and suction through brochial blocker lumen
- no need to change tube in ICU,
- ability to provide contunuous vent during insertion
Issues with ventilator management of OLV
- hypoven causes dependent lung collapse and hypercapnea (augment HPV in dependent lung worsening hypoxemia)
- hyperventilation increases elevation of dependent lung vascular resisistance (divert blood to nondependent lung) and hypocapnea (inhibit nondependent lung HPV)
100% Fi02
Increase RR 20-30% TV 10cc/kg
Considerations for pts with lung CA
- Signs mass effect
- Obstructive PNA
- SVC syndrome
- Pancoast tumor
- tracheal bronchial distortion- mass induced VQ mismatch
- mass compression of heart and great vessels
- Tumor invasion
- Hemoptysis, blood stained sputum
- Cancer related meds
- Bleomycin (interstitial pneumonitis, pulm fibrosis)
- Cisplatin: peripheral neuropathy, renal failure
- Paraneoplastic syndrome
- Lambert Eaton
- SIADH-hyponatremia vs loop diuretic), decreased serum osm,
- Cushing syndrome-Ectopic ACTH, hypokalemia, HTN, psychosis
- Parathyroid releasing hormone-hypercalemia-N/V, renal failure, weakness, arrhythmia
Features of SVC syndrome and Pacoast tumor
- SVC syndrome-intravascular thrombosis, obstruction venous drainagemucosal edema, venous engorgement of airwaysdsypnea, coughing, orthopnea
- Increased ICP 2/2 poor venous drainage
- Signs
- Neuro: facial neck and upper limb edema, nasalstuffiness, heachache, lightheadedness, papilledema, visual changes, AMS
- Cardiac: CP, orthopnea
- Pulm: dysphagia, orthopnea, hoarsness, pleural effusion
- Pancoast tumor (compression stellate, RLN, phrenic, branchial plexus Subclavian artery, Brachiocephalic vein)
What work up to order for pneumonectomy
- Cardiac (pHTN)
- EKG (RVH
- Echo: RV function (high risk of RV fxn if ppo Fev1 <40%
- Lung
- CXR (Enlarged apex RVH, Ram prominent pulm outflow tract, enlarged pulm arteries)
- ABG
- chest CT
- Pre thoracotomy assessment
- Respiratory mechanics (Fev1, FVC, MVV, RV/TLC)
- Fev1< 2L
- Post op FEv1 >40% (<20% unacceptable high risk)
- order VQ to determine contribution of resected portion to predict post resection pulm fxn (if pneumonectomy will be tolerated)
- <40% high risk right heart failure
- FVC <50% <1.5ml/kg
- Max voluntary ventilation <50%
- RV/TLC >50%
- Lung parenchyma fxn (DLCO, Pa02, PaC02)
- Ppo DLCO >40% ((<20% unacceptable high risk)
- Pa02<60
- PaCo2>45
- Cardiopulmonary reserve (Vo2 max, stair climbing, 6 min walk test, exercise Sp02)
- Max oxygen consumption >15ml/kg/min (<10 contraindicated
- Stair climb: 5 flights =Vo2 >20; 2 flights 12 <2 high risk
- 6 min walk test <200 ft Vo2 <15
- Exercise Spo02: decrease >4% increased risk
- Respiratory mechanics (Fev1, FVC, MVV, RV/TLC)
pneumonectomy post op complications
- Cardiac
- RH failure, cardiac arrhythmias,
- cardiac herniation (mediastinal shift)torsion of vessels (place back in DQ
- tx: make resected side nondependent, stop suction to empty hemithorax, consider injecting air into empty hemothorax, support hemodynamics
- PULM
- Bronchial disruption, BPF, PTX,
- resp failure, postpneumonectomy pulm edema, PE
- decreased venous return from MV and PEEP
- Hemorrhage
- Renal dysfunction
- Nerve injury: phrenic, vagal, RLN
Features of Downs syndrome
- Alantoaxial instability
- : alanto axial instability: subluxation, anterior atlantodental interval (AADI)>4-5mm in lateral view, neural canal; width, atalanto axial instability
- If signs consistent with cord compression/spine instability (numbness tingling weakness on flexion/extensiondelay case and have repeat cervical imagine and neuro surgical eval of cervical spine
- No signs likely don’t need imagine but avoid excessive extension flexion rotation
- Cardiac: bradycardia w/ sevo, 50% endocardial cushion defects (defects involving atrial, ventricular septum, and 1 or both AV valves), VSD, ASD, PDA, TOF
- Pulm: marcroglossia, micrognathia, subglottic stensosis, hypotonia and redundancy soft tissues
Why is a fib common post throacic surgery
tx?
RF
- underlying cardiopulm dz
- . intraop cardiac manipulation
- pain induced sympathetic activation
- increased R heart afterload due to pulm vascular bed reduction,
- metabolic abnormalities
When to decide if one should extubat after pneumonectomy?
Risk benefit of exchanging DLT for ICU
- ppoFev1>40% extubate
- ppoFev1 30-40%, DLCO>40% Vo2>15ml/kg extubate
- ppoFev1 20-30%, DLCO>40% Vo2>15ml/kg extubate, resection occured w VATs and/or thoracic epidural in place
con: large diameter DLT-risk mucosal injury and tracheal stenosis, lack experience ICY personelle,
pro: difficult airway
What to do during hypoxia during OLV
- 100% oxygen
- Ensure adequate placement by capnography, listening to chest, fiberoptic scope for direct visualization
- Check BP to ensure adequate perfusion
- RL shunt from collapsed lung
- Recruitment breaths
- CPAP 10 Cm H20 to nondependent lung if surgically acceptable
- PEEP 5-10 cm H20 to ventilated lung ( in healthy lungs this way result in pressure induced shunting blood to nondependent lung)
- Reinflate non dependent lung
- Discuss with surgeon about ligating pulm artery to elim shunt
- Encourage hypoxic vasoconstriction (remove agents that may blunt this)-volatile, systemic vasodilators, hypocapnia (inhibit HPV nondependent lung and increased vascular resistance in dependent lung