What is the common cause for ARDs?
Common features between ARDS and CHF!
- Symptoms of anxiety, dyspnea, tachypnea
- Reduced lung volumes and decreased compliance
- Arterial blood gases intially show respiratory alkalosis and arterial hypoxemia
- Chest xray shows diffuse alveolar and interstitial inflitrates
Role of organ to organ interactions
- Factors outside lung may play role in initiation & progression of ARDS & multiple organ dysfunction syndrome (MODS)
- Treatment strategy: selective decontamination, early enteral feeding
The gut-liver-lung axis may be most influential in...
Causing the systemic inflammatory response associated with ARDS and MODS
- GI tract & liver function is often compromised in critical illness
- wide-spread use of antibiotics leads to overgrowth of antibiotic resistant bacteria in gut
- These bacteria & their toxic byproducts escape gut, taken up by reticuloendothelial (RE) cells in the liver which activate & perpetuate systemic inflammatory response & systemic organ injury
- Liver is responsible for breakdown of proinflammatory mediators
Exudative Phase of ARDS
- (1-3 days)
- Characterized by diffuse damage to alveolar and blood vessels and the influx of inflammatory cells into interstitium
- Filled alveolar spaces with cellular debris & plasma proteins; destruction of Type I pneumocytes
The exudative phase of ARDS is often difficult to differentiate from...
Respiratory failure related to hydrostatic pulmonary edema (CHF)
Patients with ARDS have...
- Profound dyspnea
- Refractory hypoxemia
THe exudative phase of ARDS may be...
self limited or may progress to a fibroproliferative phase
Fibroproliferative phase of ARDS
- 3 to 7 days
- Process of lung repair
- Hyperplasia of alveolar Type II pneumocytes & proliferation of fibroblasts
- Fibroblasts form intraalveolar & interstitial fibrosis
- Extent of fibrosis formation determines disability in those who survive
- Lung remodeling process, degree and reversibility varies greatly
- An intact alveolar basement membrane is necessary for normal repair
The clinicals findings in ARDS!
- Peripheral infiltrates on chest xray
- PCWP< 18 mm Hg
- BALF is proteinaceous and inflammatory
- Pathologic examination shows diffuse alveolar damange, type ll pneumocyte hyperplasia with or without fibrosis
- Ratio of PaO2/FiO2 < 200
- air bronchograms, normal cardiac size
Know about oxygen delievery and PEEP with ARDS patients!
- Recruits additional alveoli
- Improved oxygenation
- May allow for ↓FIO2 Rule and airway shear trauma
- Use the lowest level of PEEP that will maintain adquate oxygenation
- ↑ventilation-perfusion matching
- Patient tolerance varies due to hemodynamic instability & worsening gas exchange
How much of the lung is not functioning in patents with ARDS?
Thus, in ARDS, the lungs are effectively diminished in size to 20 to 30% of normal
What are some other causes of lung cancer besides smoking?
- Occupational and environment exposure
- Genetic predisposition
- Dietary factors
- Air pollution
What is the purpose of staging cancer?
Most important prognostic variable in lung cancer, assesses extent of disease & selection of therapy
What does T, M, N stand for in TNM staging?
- Status of primary tumor (T1-T4)
- Local & regional lymph node involvement (N0-N3)
- Presence of metastasis (M) 1A-4
The common organs that lung cancer commonly passes to?
- Adrenal glands
What pulmonary function test are used to determine wheither a person can tolerate a lung recession?
What is the best treatment for non small cells cancer?
Surgical resection offers best survivial
How is small cells cancer staged?
Limited versus extensive
Limited stage for small cell lung cancer
- Combination chemothrapy with concurrent hyperfractionated radiotherapy if prformance status is adequate
- Prophylactic cranial radiation for those with a complete response to chemoradiotherapy
Extensive stage of small cell lung cancer
Combination chemotherapy if performance status is adequate
What kind of clinicals symptons might a patient have with tumor growth in the central airways?
- Features of large airway obstruction
- dyspnea, dysphagia
- esophageal compression), post-obstructive pneumonitis, hoarseness, SVC syndrome, chest pain if pleura is involved, palpitation, syncope
What systems are affected by metastasize?
- Adrenal glands
- Supraclavicular lymph nodes
Symptoms of Metastatic or if lung cancer spreads byond the lung!
- Weight loss
- Neurological symptoms
- Localized bone pain
What is associated with respiratory muscle weakness?
The pulmonary consequences of nuromuscular disease!
- Hyper or hypo ventilation
- Sleep apnea
- Atelectasis with resulting hypoxemia
- Pulmonary hypertension
- Cor pulmonale
- Respiratory failure is frequent cause of death
Among the many neuromuscular problems causing pulmonary dysfunction, respiratory muscle weakness that leads to...
- Ventilatory insufficiency
Symptoms of respiratory muscle weakness due to nuromuscular disease!
- Exterional dyspnea
- Symptoms of cor pulmonale
A decrease in FEV1 and VC greater than 20% when a patient moves from the seated to the supine position indicates...
The inability to generate normal respiratory pressures...
Is reflected in a decreased maximal inspiratory pressure (PImax)
Expiratory muscle weakness is characterized by...
A decreased maximal expiratory pressure (PEmax)
Progressive inspiratory muscle weakness leads to...
Expiratory muscle weakness is associated with what problem?
Production of cough to clear pulmonary secretions
Decreased conduction of CNS impulse to peripheral muscles results in...
- Most common peripheral neuropathy
- Characerized by paralysis and hyporeflexia,
- Self-limiting disease
- Is a demyelinating process caused by autoantibodies directed against nerve sheath
Autonomic nervous system problems with guillian barre syndrome!
- Intermittent muscle weakness which worsens on repetitive stimulation and improves with anticholinesterase meds (neostigmine, tensilon)
- Abnormalities of thymus gland common
- Muscle weakness progresses during the day with repetitive use
Myasthenia Gravis typically occurs in...
Yonger female patients
The pulmonary complications of Myasthenia Gravis!
- Upper airway obstruction
- Respiratory failure
- Decrease in TLC, VC, MIP, MEP
acute event – respiratory failure or loss of airway patency – intubation and PPV required stat
Guillian Barre syndrome can be weaned from mechanical ventilation when...
- VC greater than 18 mm/kg
- Transdiphragmatic pressure greater than 31 cm H2O
- PImax greater than 30 cm H2O
How is paralyzed diaphgram diagnosed?
- Phrenic nerve arises form spinal cord at C3-C5
- Damage or interruption of this nerve leads to paralysis of ipsilateral hemidiaphragm
- Bilateral interruption is seen in high cervical cord injury and results in complete diaphragmatic paralysis
Patients with unilateral diaphragmatic paralysis..
May have a 15 to 20% reduction in VC and TLC in the upright position and a further reduction while supine
Diaphragmatic paralysis is diagnosed...
- Most often with chest radiograph
- paralyzed side is displaced upward; fluoroscopy – effected side paradoxically rises during “sniff”
Amyotropic lateral sclerosis
- Progressive degeneration of upper & lower motor neurons
- Onset at mid-to late life with male predominance
- Poor prognosis – 80% die within 5 years of onset
- Monitor FVC, MIP, MEP – assesses ability to clear secretions, maintain gas exchange
- MEP> 40cm needed to generate cough
What are the hallmark signs of diaphragmatic paralisis?
- Patients adopt rapid, shallow breathing, using accessory inspiratory muscles
- Abdominal paradox or paradoxical breathing is hallmark of significant diaphragmatic weakness – results in orthopnea
Where does a spinal cord injury occur to affect the diaphragm?
- Middle to low cervical cord lesions (C3-8)
- The diaphgram receives its innervation from C3-5
What are the breathing patterns of a patient who has had a stroke?
- Cheyne strokes respirations
What are the complications of flail chest?
- V/Q mismatch
- Decreased compliance
Repeated episodes of complete cessation of airflow for 10 seconds or longer
- Significant decrease in breathing without complete cessation of airflow
- 30% airflow decrease and 4% oxygen desaturation
What causes obstructive sleep apnea?
- Small or unstable pharyngeal airway caused by:
- Upper body obesity
- Tonsilar hypertrophy
- Skeletal factors such as small or recessed chin
What are some symptoms of OSA?
- Habitual snoring
- Sensations of nocturnal choking, gasping, snorting
- Witnessed by bed partner
- Fatigue, EDS, irritability
- Morning headaches, depression
- Nocturnal reflux, nocturia, chronic nasal obstruction
What are some problems with CPAP?
- Feelings of claustrophobia
- Nasal congestion
- Skin irritation
- Nasal dryness
Auto CPAP or smart PAP
Adjusts pressure when abnormal upper airway function is detected
UPPP or palatal surgery
- Portions of soft palate, uvula, additional excess tissue are removed
- Less than 50% success rate
- Not currently recommended
- Performed with a standard cold knife technique and or laser
Central sleep apnea
- Associated with CHF & stroke
- Patients have periodic breathing – waxing & waning of respiratory drive
- Cheyne-Stokes is a severe type of periodic breathing
What is the association between sleep apnea and systemic hypertension?
Repetitive upper airway closure & opening increases sympathetic tone
Increased sympathetic tone is caused by...
- Episodes of hypoxemia & hypercapnia
- arousals & microarousals also increase sympathetic response
Apnea-hypopnea index (AHI) or the respiratory distrubance index (RDI)
- Number of apnea / hypopnea events per hour of sleep
- AHI >30 = severe sleep apnea
- AHI = 15-30 moderate
- AHI = 5-15 mild
- AHI < 5 = normal
The use of alcohol with sleep apnea?
- Decreases the arousal threshold and can increase the duration of apnea
- Reduce upper airway muscle tone, causing the airway to be more compliant and more prone to complete or partial closure