Module 3: Shortness of Breath Flashcards
(123 cards)
SOB is a common symptom of?
lung disease, myocardial ischemia or dysfunction, systemic illness (anemia, shock, sepsis, fever), obesity, deconditioning
is SOB objective or subjective?
subjective experience of breathing discomfort
what are respiratory system dyspnea
- central controller 2. ventilatory pump 3. gas exchanger
what are CV system dyspnea?
- acute ischemia 2. systolic dysfunction 3. valvular disorders 4. pericardial diseases
what is critical asthma syndrome?
umbrella term: life threatening, status asthmaticus, near-fatal asthma
what are the symptoms of critical asthma syndrome?
- inability to speak 2. reduced peak expiratory flow rate of <25% of a patient’s personal best 3. failed response to frequent bronchodilators and IV steroids 4. require emergency care 5. prone to complications 6. utilize significant resources
what is the hallmark physical examination in acute respiratory failure
- inability to speak 2. upright posture 3. use of accessory muscles of respiratory and paradoxically 4. minimal wheezing –>indicates impending loss of air movement
what is the progress to respiratory failure?
emergent airway management. lethargy, loss of wheezing, cyanosis, reduced or paradoxical respiratory efforts less obvious: early signs of respiratory exhaustion such as progressively shallow respirations, weakness, progression loss of alertness
what does a declining course look like?
- first line is bronchodialtors, failing bronchodilators > 20 minutes, increased care, worsening respirator acidosis, signs of increasing fatigue.
- acute respiratory alkalosis occurs early
- acute respiroatyr acidosis is LATE
- NIPPV - can be used selectively - reduce barotrauma, improve comfort reduce nosocomial infections
- needs to be placed early and closley monitor - if not improving need to intubate (this is not a rescue treatment)
- contraindications: vomiting, obtunded, combative, AMS
what are absolute indications for endotracheal intubation
- cardio pulmonary arrest or apnea
- imminent respiratory failure (paradoxical breathing, lethargy, hypopnea)
- acute respiratory failure with PaO2 < 60 and/or PaCO2>50
- acute on chronic respiratory failure
relative indications for ET intubation
- hypercarbia PaCO2>50 or increase > 5 mmHg/hour
- worsening respiratory acidosis
- inability to care for patient appropriately
- signs of fatigue (shallow respirations)
- failure to respond to bronchodilator therapy
how do you intubate an awake but failing patient
- awake & upright fiberoptic broncchoscopic
- induction without neuromuscular blockade
- RSI
- don’t use nasotracheal intubation d/t potential nasal polyposis
what do you do for intubation for imminent respiratory failure
- RSI
- largest ETT possible, NO over bagging
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what are the induction agents recommended for ET intubation for imminent respiratory failure
- hypotensive/normotensive - ketamine (caution CV disease)
- hypertensive - propofol (give with volume)
- hemodynamic uncerntainty - etomidate
what are the recommendations for neuromuscular blocking agents
- succinylcoline - contraindicated in malignant hyperthermia, hyperkalemia, elevated intra-occular pressure and burns
- rocuronium or vecuronium - may have prolonged effect
what are some complications with intubation
- hypotension
- dynamic hyperinflation and increased intra-thoracic pressures may impair R-sided cardiac venous return
- arrhythmias from high dose beta-2-agonists and eletrolyte abnormalities
- barotrauma
- laryngospasm
- worsening bronchospasm
- seizures
- aspiration
- intravascular volume depletion d/t work of breathing with accompanying tachypnea and diaphoresis result in significant insensible volume loss
- post intubation PTX or pneumomediastinum - uncommon but an be fatal
physical exam cluse of pneumothorax
- tracheal deviation away from affected side
- anterior chest or neck crepitus
- unilateral loss of lung sounds
- tachycardia
- hypotension
- central cyanosis
- low pulsus paradoxus -> presence of severe hyperinflation causing extracardiac tamponade
- CT is gold standard for diagnosing PTX-> bedside ultrasound is emerging
- if US is not immediately available, and patient is deteriorating->empiric chest tube for decompression (tension PTX) before obtaining CXR
what are labs/tests you need to do?
- ABG essential - trend this
- describes their ability to ventilate and oxygenate
- eval for concomitant acid-base disturbances: metabolic acidosis, metabolic alkalosis (resulting from volume depletion) or respiratory alkalosis (pulmonary embolus)
- normal ABG with increasing WOB is ominous sign
- may have hypercarbia d/t airflow obstruction, hypoxemia from V/Q defects
- ECG (ischemia, arrhythmias - especially in older adults)
- CBC - infection
- chemitries
what other additional tests do you want?
- chest imaging
- CXR (most common)
- PEFR and bedside spirometry
- flow volume loops - this helps figure out the reason for the exacerbation/diagnosis
what is the treatment?
- goal is to maintain adequate perfusion and cardiac output
- rapid IVF
- mechanical ventilation
- will have some degree of hypoxemia d/t hypercapnia and V/Q mismtch
- PaO2 <55 is uncommon and should prompt search for additional processes (ex: intrapulmonary shunt from PNA or atelectasis)
- supplemental O2 (generally hypercarbic, not hypoxic)
- other causes of hypoxemia include PTX or pulmonary aspiration
treatment medications
- bronchodilators
- systemic corticosteroids
- leukotriene receptor agonists (montelukast)
- IV magnesium
- smooth muscle relaxer (bronchodilator)
- if refractory: SQ terbutaline & epi
- sedation & put on vent. if needed
what order should you think about fixing things for mechanical ventlation
- treat dynamic hyperinflation 1st & gas exchange abnormalities 2nd
does mechanical ventilation alone help the patient?
- no.
- have to watch for elevated airway resistance and mucous plugging that leads to airflow obtstruct & dynamic hyperinflation as gas is not able to escape
- inspiratory capacity and inspiratory reserve volumes fall as functional residual capacity inreases
- as IC approaches TLC inspiratory efforts are impeded by over stretched inspiratory muscles & diaphraghm flattens
- develops respiratory fatigue–>respiratory failure
- increased intra-thoracic pressure in dynamic hyperinflation leads to impaired venous return to the R heart and hemodynamic compromise
- high intra thoracic pressures may worsen dead space by reducing blood flow to alveolar units thereby worsening ventilation –> respiraotry acidosis