Respiratory Flashcards
What does surfactant do?
lowers surface tension, keeping the alveoli from collapsing after exhalation
What does ARDS stand for
Acute Respiratory Distress Syndrome
What is respiratory failure?
Failure in gas exchange due to lung failure
How does respiratory failure occur?
Impaired gas exchange, decreased ventilation or both
What are the two types of respiratory failure and what happens?
TYPE 1 - Hypoxemic - due to failure of gas exchange function of lung.
TYPE 2 - Hypercapneic - hypoxemic due to ventilatiory pump failure (decreased ventilations)
Causes of each type of respiratory failure?
TYPE 1 - Restrictive lung disease, severe pneumonia, atelactasis
TYPE 2 - Upper airway obstruction, laryngospasm, Weak/paralyzed resp muscles, OD, Muscular Dystrophy, Chest wall injury, Asthma
What is a VQ mismatch?
areas of lung ventilated but not perfused or vice versa
Describe the VQ mismatch seen in advanced COPD
CO2 retention due to decreased effective alveolar ventilation leads to a region of the lung not being perfused and thus no gas exchange.
Whats important to remember when oxygenating a potential VQ mismatch patient?
O2 success depends on degree of mismatching present, and in prolonged periods in people w/ chronic lung disease O2 may decrease respiratory drive.
What is impaired diffusion?
gas exchange between the alveolar air and pulmonary blood is impeded because of an increase in the distance of diffusion or a decrease in the permeability or surface area of the respiratory membranes to the movement of gases.
How does increasing flow of O2 treat impaired diffusion?
overcomes decrease in diffusion by establishing a larger alveolar to capillary diffusion gradient.
What is type 2 respiratory failure?
Hypercapnic - unable to maintain sufficient alveolar ventilation to eliminate CO2 –> PaCO2 higher than 50, build-up of CO2 that alters pH as a result
What O2 sats and CO2 would be considered respiratory failure?
arterial PO2 of less than 60% on RA, CO2 of greater than 45mmhg or both.
Why is respiratory acidosis usually present in respiratory failure?
no compensatory mechanism for CO2 retention and thus increased acid production.
Signs of hypoxemia?
Cyanosis, tachypnea, restless, confusion, anxiety, delerium, fatigue, cardiac arrhythmias, HTN.
Initial CVS effects of hypoxemia?
tachycardia, increased CO, increased BP that can lead to arrhythmias
In hypoxemia what happens when the pulmonary vasculature constricts and why does it constrict?
constricts in response to decreased alveolar PO2 leading to hypoxemia and presenting with similar signs as cor pulmonale
What can profound acute hypoxemia cause?
retinal hemorrhages, convulsions, permanent brain damage
Peri arrest findings of someone in hypoxemic respiratory failure?
hypotension, bradycardia due to failure of compensatory mechanisms
What is hypercapnia?
Increased CO2 - adverse consequences due to resp acidosis - leading to depression of cardiac contractility, decreased resp muscle contractility and arterial vasodilation
What happens when etco2 goes above 60?
air hunger and tachypnea
What happens when end tidal increases above 80?
lethargy, disorientation, semi-comatose
TX of both types of resp failure?
Staged oxygen approach: O2 NC –> NRB –> CPAP/BVM (NIPV) –> Intubate
Reasons for impaired gas exchange?
Direct membrane damage, collection of fluid in alveoli, collection of fluid in interstitial space, collapse of alveoli.
What is a pulmonary shunt?
Perfusing alveoli that can’t exchange gases.
What is a shunt?
Good perfusion without ventilation of alveoli
What is physiologic dead space?
Good ventilation without perfusion
Indications of potential intubation?
Apnea/resp arrest, ALOC, resp muscle fatigue, unstable, refractory hypoxemia + hypercapnia
Goals of Tx in Respiratory Failure?
hypoxemia correction, resp acidosis correction, allow resp muscles relax.
What is the classic trait or ARDS?
accumulation of fluid in the lungs leading to alveoli collapse
How does ARDS work?
capillary membrane that surrounds alveoli leaks fluid into the sac, leading to decreased gas exchange, collapse of sac, hypoxemia and organ failure.
What happens when the hyaline membrane develops?
lungs become less elastic, decreased lung compliance and subsequent V/Q mismathc
What is hyperventilation syndrome?
Too much CO2 blow off, usually anxiety related.
S/S of hyperventilation syndrome apart from the obvious
agitation, terror, cp, parasthesia, stiffness of arms or fingers. presyncope or syncope.
Why does anxious patient have the stiffness in there hands?
Due to too much CO2 blow off leading to alkalosis
Why do acidotic patients hyperventilate?
Too blow off co2 and drive ph down, it is a compensatory mechanism
Whats important to note about hyperventilation?
Hyperventilation caused by metabolic crisis is self limiting
What is a pleural effusion?
collection of fluid in the pleural cavity
What is the pleural cavity?
pleural space between parietal and visceral pleura
What happens in the exudative state of pleural effusion?
inflammation –> capillaries are much more leaky and leads to protein leaking
What happens in the transudative state of pleural effusion?
fluid moves across into the pleural space (fluid shift).
How does CHF lead to a pleural effusion?
no pump leads to back up of blood and increased pressure increases further and forces fluid out of capillaries into the pleural space
What is dull percussion an indication of?
Fluid within the lungs or pleural space
Symptoms of pleural effusion?
pleuritic pain, decreased breath sounds, dull to percuss, decreased tactile fremitus, tracheal deviation, sob worse when laying down (orthopnea)
What is pnemonia??
Acute inflammation of lungs caused by infection that brings water into the lung tissue usually caused by bacteria or virus
What is lobar pneumonia?
Complete consolidation of one lobe of the lung
What are bronchial breath sounds?
Harsh sounds equally heard on insp and exp
What are the 4 stages of the pneumonia pathological process?
Edema - alveoli filled with protein rich edema fluid
red hepatization - capillary congestion
grey hepatization - macrophages kill everything
resoloution - lung returns to normal
What is the lung parenchyma?
Tissues that make up walls of capillaries of alveoli
What is pulmonary edema?
fluid accumulation from blood plasma in the interstitial space of the lungs due to increase in LV filling pressures. acute severe LV failure with pulmonary venous htn leads to alveolar flooding
Causes of Pulmonary Edema?
HF, ACS, arrhythmia, acute valvular disorder, LV fluid overload
What is the cardiac reserve?
Max percentile CO can be increased above normal
S/S of pulm edema
dyspnea, hemoptysis, pallor, cyanosis, fine inspiratory crackles, cardiac wheeze. pulse weak and rapid, if bp is hypotensive it is a ominous sign. Heart sounds summation gallop - merger of third and fourth sounds
What can mimic pulmonary edema?
COPD if cor pulmonale is present
What is cor pulmonale?
R heart failure
Treatments of Pulmonary Edema based on etiology? CHF, SVT, VT, AF, MI, HTN? (Name all tx for each condition)
CHF - CPAP/Nitrates
SVT - Cardiovert or adenosine
VT - Cardiovert or amio
AF - depending on patient presentation, if ctas 1-2 cardiovert
MI - transport early, manage pain and stressors on heart
What is the pathologic process of pulm edema in severe htn?
LV can’t effectively pump due to increased after load (systemic pressures) –> blood backs up into LA –> pulm veins –> pulm capillaries –> pulm htn –> edema
