Lecture

• Total lung capacity: amount of air that can be inhaled into the lungs on maximum inspiration
• Tidal volume: amount of air inhaled and exhaled in 1 breath
• Vital capacity: includes maximal inspiration and expiration
• Residual volume: amount of air leftover after maximal expiration
• Residual volume is very relevant to COPD because of air trapping that occurs
• Ventilation contains 3 elements: neurological, innervation and diaphragm/intercostals
• Sources of upper airway obstruction: FBAO, epiglottitis, burns and trauma
• Source of lower airway obstruction: asthma and airway edema
• Very rare to have to have lower airway burns but could be caused by certain gasses or chemicals
• Things that interfere the alveolar membrane will also interfere with gas exchange
• It takes about 1 minute for a RBC to circulate around the entire body so if O2 is applied, there should be a change within that time otherwise there's an issue
• things affecting diffusion: inadequate O2(Histotoxic; CO poisoning/Cyanide), capillary bed pathology, severe atherosclerosis, alveolar pathology and interstitial space problem(Pulmonary edema or near drowning)
• Saline doesn't have O2 in it so while it can help with blood pressure, it only does so much for SPO2 and maintaining perfusion
• To build a differential Dx: think of anatomical components, think of worst first(Most life threatening/common) and think of less likely options as you work through assessments
• Within chief complaint of SOB, consider word dyspnea, coughing(productive or nah) and frothy sputum
• If there's no life threats, do an incident hx, focused assessment and then a history
• In incident hx you're looking for: URI, colds, allergens from environment, cats/dogs, tobacco smoke, cold/dry air, exercise and GERD(gastric acid could cause bronchospasm)
• Majority of respiratory problems are reactionary
• Much harder to exhale in asthma
• For PMHx in asthma, ask if they have a prior hx of asthma exacerbations, ask if they've been intubated before, ask if they've been hospitalized for it and ask about corticosteroid use(how recent and are they still on it)
• On assessment for the head/neck: 1-2 word dyspnea, altered LOAs, head bobbing, central cyanosis, pursed lip breathing, tracheal tugging, JVD and retractions
• On assessment for chest: symmetry, barrel chest, indrawing, retractions, accessory muscle use, positioning, depth/rate/regularity with breaths, chest auscultation and if coughing, is it productive
• Generally chest auscultation can be done within the first 2 minutes of PT contact
• Fine crackles occur in smaller airways and coarse on larger ones
• Crackles are often heard on inspiration and usually bilateral in the lungs
• Wheezes on inspiration is usually an obstruction like FBAO
• Wheezes on expiration is usually asthma but it can also be on inspiration
• Stridor is usually heard best over the neck
• On assessment for extremities: ask for numbness, tingling, peripheral cyanosis and edema and colour/temperature/condition of the skin
• On physical for pelvis: there could be incontinence caused by hypoxia
• Seesaw breathing: type of abdominal breathing for kids in which when they inhale chest goes up and abdomen goes down and vice-versa for exhale.

  
• Risk factors for exacerbation of asthma: gender(Females have more exacerbations), using 2 or more rescue inhalers per month, having a Hx of exacerbations, have other chronic health problems, smoker, not using meds as directed and having URI/Cold/Flu
• Bradycardia in an asthmatic PT is an ominous sign of late stage hypoxia or an arrhythmia caused by the lack of O2
• As air trapping increases in Pts, there's more pressure within the chest which could affect the hearts pumping ability.
• Respiratory rate alone is not an indicator of distress
• When bronchioles are normal, laminar airflow is present in which air flows without any resistance. Lack of laminar airflow increases resistance
• ETCO2 has "sharkfins" in Asthma, COPD and CHF
• Indications for PPV: Airway protection in a patient cannot maintain their own airways, hypercapnic respiratory failure, circulatory failure and poor tidal volume
• Asthma is an air trapping disorder so PPV can cause them to fill up with air.
• When PPVing asthma patients: reduce the volume of ventilations and ventilate at 8 to 10 breaths per minute