Pulmonary Pathophysiology I PPT Flashcards
EXAM 3
Pulmonary Hypertension (PH) Definition:
- A mean pulmonary artery pressure of at least 25 mmHg
- A pulmonary capillary occlusion pressure of 15 mmHg or less.
Pulmonary Hypertension (PH) Etiology:
- Drug effects
- Connective tissue disorders
- COPD
- Sarcoidosis
- Idiopathic/genetic factors
PAH 5 Main categories:
- Pulmonary arterial hypertension itself (PAH)
- PH due to left heart disease
- PH due to lung diseases and/or hypoxia
- Chronic thromboembolic pulmonary hypertension
- Causes with unknown mechanisms
Treatment of Cor Pulmonale:
- Diuretics to reduce cardiac workload; use cautiously to maintain adequate preload.
- Use supplemental O2 to achieve PaO2 > 60 mmHg or Saturation > 90%.
- Heart Lung Transplantation in severe cases.
Pre-operative Care for Cor Pulmonale:
- Eliminate or control pulmonary infections.
- Reverse bronchospasm.
- Improve secretion clearance.
- Expand collapsed/poorly ventilated alveoli.
- Correct hydration and electrolyte imbalances.
Intra-operative Management for Cor Pulmonale:
- Use regional anesthesia when high sensory levels aren’t needed.
Key points:
- Avoid hypotension.
- Volatile agents that decrease PVR are preferred.
- Isoflurane can lower PAP
- Avoid N2O as it increases PVR
- Intravenous agents generally have little effect on PVR.
- Ketamine should be avoided due to its potential to increase PVR.
- Crucial to avoid any manipulations that could increase PAP during anesthesia stages.
Intra-operative Principles for Cor Pulmonale:
- Maintain good oxygenation.
- Avoid acidosis.
- Avoid exogenous and endogenous vasoconstrictors.
- Avoid stimuli that increase sympathetic tone.
- Avoid hypothermia.
Pulmonary Embolism (PE) is caused by:
- A dislodged thrombus entering the pulmonary vascular bed.
- Significant thrombus obstruction leads to forward ischemia and rearward cardiac overload.
Pulmonary Embolism (PE) Etiology:
- Primarily caused by Deep Vein Thrombosis (DVT).
- Venous thrombi formation promoted by
Virchow’s triad:
- Stasis of blood flow.
- Venous injury.
- Hypercoagulable state.
Thromboembolic Risk Factors:
- Hereditary Thrombophilias
- Acquired Surgical Predisposition
- Acquired Medical predisposition
Thromboembolic Risk Factors
Hereditary Thrombophilias:
- Protein C deficiency
- Protein S deficiency
- Antithrombin II deficiency
- Factor V leiden mutation
- Prothrombin 20210 G A variation
- Hyperhomocysteinemia
- Dysfibrinogenemia
- Familial plasminogen deficiency
Thromboembolic Risk Factors
Acquired Surgical Predispositions
- Major thoracic, abdominal, or neuro procedures
- General anesthsia > 30 min
- Hip arthroplasty
- Knee arthroplasty
- Knee arthroscopy
- Hip fracture
- Major trauma
- Open prostatectomy
- Spinal cord injury
Thromboembolic Risk Factors
Acquired Medical Predispositions
- Previous venenous Thromboembolism
- Advance age > 60 yr
- Malignancy
- CHF
- CVA
- Nephrotic syndrome
- Estrogen therapy
- Pregnancy
- Postpartum period
- Obesity
- Prolonged immobilization
- Antiphospholipid antibody syndrome
- Lupus anticoagulant
- Inflammatory bowel disease
- Paroxysmal nocturnal hemoglobinuria
- Behcet syndrome
Pulmonary Embolism (PE) Pathophysiology:
- Occlusion of the pulmonary artery decreases ventilation distal to the obstruction.
- Result: Bronchoconstriction due to alveolar PCO2 (PACO2) effect on local small airways.
- Reduced airflow to the unperfused lung minimizes wasted ventilation.
Pulmonary Embolism (PE) Clinical Features:
- Clinical presentation heavily influenced by embolus size.
- Signs and symptoms of PE are varied and nonspecific, overlapping with many disorders.
Differential Dx of Acute Intraoperative PE
- Anaphylactic reaction
- Aortic dissection
- Aortic stenosis
- Brain stem stroke
- Bronchospasm
- Heart failure
- Hypertrophic cardiomyopathy
- Myocardial infarction
- Pulmonary hypertension
- Tension pneumothorax
Most common symptoms of Pulmonary Embolism:
- Unexplained dyspnea
- Chest pain (either pleuritic or atypical)
- Anxiety
- Cough
Most common signs of Pulmonary Embolism:
- Tachypnea
- Tachycardia
- Low-grade fever
- Left parasternal lift
- JVD
- Tricuspid regurgitant murmur
- Accentuated P2
- Hemoptysis
- Leg edema, erythema, tenderness
Diagnostic tests for suspected Pulmonary Embolism
- Chest CT (most accurate)
- D-dimer (rule out)
ECG signs assocaited with PE
- Tachycardia
- Negative T wave in V1-V5
- Negative T wave in II, III, aVF
- Right axis deviation > 90 degrees
- Pulmonary P wave
- R > S or Q in VR
- RV ischemia
- Complete or incomplete RBBB
Medical Management for Acute PE
- Begin UFH IV
- aPTT goal 80 sec
- Volume resucitation 500-1000 mL
- Give vasopressors and Inotropes
- Determine risk of thrombolytic therapy
- Consider IVC filter, embolectomy, sx embolectomy if therapy is too risky
- Avoid combination of Thrombolytics and IVC filter insertion
Prevention of Venous Thromboembolism by condition
Pulmonary Embolism (PE) Anesthetic Management:
- Focus on preventing further embolism and supporting respiratory and cardiovascular function.
- Aims to maintain vital organ function and minimize anesthetic-induced myocardial depression.
PE Anesthesia induction and maintenance must avoid:
- Worsening arterial hypoxemia
- Systemic hypotension
- Pulmonary hypertension
Part II
Pulmonary Embolism (PE) Anesthetic Management:
- Anesthesia should use drugs that avoid significant myocardial depression.
- AVOID Nitrous oxide potential to increase PVR
- A nNMBs drug that does not release histamine is preferred for its safer profile.
Avoid: Mivacurium & Atracurium
Initial indicators of Pulmonary Embolism (PE) During Anesthesia:
- Decrease PETCO2
- Tachycardia