Pulmonary Flashcards
when an endotracheal tube is placed, it must be 2-3 cm above what to ensure equal inflation in both lungs?
carina
what must be done after intubation & daily to ensure correct placement?
CXR
what is the parietal pleura?
membrane lining the chest wall
what is the visceral pleura?
membrane lining the lung parenchyma
what allows sliding back & forth whenever we are breathing?
2-3 tsp of fluid inside the parietal pleura & visceral pleura
what keeps the lungs from collapsing between the pleural space?
-5 cm H2o pressure (vacuum pressure)
why would there be a risk for damage related to the thinness of the alveoli wall?
too much positive pressure
what is the difference between type I & type II alveoli cells?
type I compose 90% of alveolar surface area & type II cells produce pulmonary surfactant
what is the importance of pulmonary surfactant? name 3 things
- decreases surface tension in the alveoli
- makes it easier to inflate alveoli during inspiration
- prevents collapse during expiration
what are connected from alveoli to alveoli that clean to maintain the sterility of the alveoli & lungs?
macrophages
what is ventilation & what is it often referred to?
movement of air in & out of the lungs (often referred to as external respiration) (movement of air between the atmosphere & alveoli)
what is perfusion & what does it focus on?
movement / flow of blood (focuses on alveolar capillary)
what is diffusion? it occurs from an area of _____ concentration to _____ concentration
movement of gases across the pulmonary membrane (occurs from an area of high concentration to low concentration)
which 4 things is alveolar diffusion affected by?
- decreased surface area
- thickness of alveolar capillary membrane
- partial pressure of gases (CO2 & O2)
- solubility of the gas (CO2 diffuses across alveolar capillary membrane 20 times faster than O2)
a patient will often become hypoxemic before becoming _____
hypercapnic
what does a shunt unit mean on a VQ scan?
- perfusion > ventilation
- blood passes alveolus w out gas exchange
EXs: pneumonia, atelectasis, tumor, mucus plugs
what does a deadspace unit mean on a VQ scan?
- ventilation > perfusion
- does not participate in gas exchange
EXs: PE or pulmonary infarction
20% shunt =
severe hypoxia
describe the two ways O2 is carried into the blood
- 97% bound to hemoglobin (SaO2)
- 3% dissolved in plasma (PaO2) (partial pressure of oxygen)
what does SaO2 measure?
saturation of arterial blood (O2 saturation of Hgb)
how is the PaO2 measured?
obtaining an ABG
list two ways the saturation of hemoglobin is measured
- ABGs (SaO2) (direct measurement; expensive & painful)
- pulse oximetry (SpO2) (indirect measurement & often times can get false readings)
name some signs & symptoms of hypoxemia
- tachypnea, hyperventilation, dyspnea
- use of accessory muscles / abdominal breathing
- cool, pale, clammy, skin (cyanosis)
- restlessness, agitation, irritability, confusion, personality changes, decreased LOC
- tachycardia, hypertension, palpitations, CP, dysrhythmias
which part of an ABG tells us the patient’s ventilation status?
PaCO2
what measures the adequacy of ventilation?
PaCO2
what does it mean if a patient’s PaCO2 is too high?
the patient is not moving enough air (decreased ventilation or hypoventilation) not breathing fast enough or not taking quality breaths
what does it mean if a patient’s PaCO2 is too low?
the patient is moving TOO MUCH air (hyperventilation) or breathing off too much CO2
which tool is noninvasive & measures the end tidal CO2 or the amount of CO2 being exhaled w each breath?
Capnography
what are some signs / symptoms of hypercapnia / hypercarbia?
same as hypoxemia
- drowsiness
- HA, decreased LOC, blurred vision, confusion, seizures
- flushed, clammy skin
what is a patient often placed on if they are hypercapnic?
CIPAP / BIPAP or intubation
what is the normal range for pH?
7.35 - 7.45
what is the normal range for PaO2?
80 - 100
what is the normal SaO2 range?
93% - 99%
what is the normal PaCO2 range?
35 - 45
what is the normal range for HCO3?
22 - 26
what is the difference between correction
& compensation?
correction: process by which the same system that is affected changes to bring pH back to normal
EX: not breathing fast enough so CO2 levels increase
compensation: process by which other system changes to attempt to bring the pH back to normal
EX: respiratory issue (being acidotic) & kidneys (metabolic parameter) correcting the acidosis caused by respiratory
if there is a PaO2 of 60, what will the SaO2 be?
90% or less
metabolic acidosis can cause decreased LOC that results in ______
respiratory acidosis (shallower breathing)
what is the goal of O2 therapy?
to deliver the least amount necessary
how much can a nasal cannula deliver & what is the percentage of inspired oxygen?
1-6 L/min
21-44% of FiO2
how much can a high flow nasal cannula deliver & what is the percentage of inspired oxygen?
1-60 L/min
21 - 100% FiO2
how much FiO2 do we breathe naturally?
20-21%
what type of situations is a nonrebreather often seen in?
emergent situations when transporting a patient from a floor to the ICU
describe the pathophysiology of acute respiratory failure & how it usually occurs
inadequate gas exchange; usually occurs secondary to another disorder like pneumonia, atelectasis, tumor or PE
(problem w oxygenation or CO2 elimination or both)
what do ABGs reveal when a pt has acute resp failure?
hypoxemia and / or hypercapnia
name a couple causes of acute resp failure
- intrapulmonary (lower airways, fluid build up or collapse of alveoli)
- extra pulmonary (CNS injury, neuromuscular disorders like MS or ALS, pneumothorax or hemothorax, pleura or an upper airway disorder)
how do you treat acute resp failure?
improving oxygentation & ventilation
- CPAP / BiPAP / NIV mask
- intubation if necessary
treat cause while trying to optimize & stabilize
describe which type of pressure a biPAP provides
positive pressure on both inspiration AND expiration
INSPIRATORY & EXPIRATORY PRESSURES ARE DIFFERENT!
what does an IPAP help with?
helps get appropriate size of breath / tidal volume to breathe off CO2
what does an EPAP help with?
helps maintain alveolar pressure / keeping them open to help w oxygenation
describe which type of pressure a CPAP provides
continuous positive airway pressure; inspiratory & expiratory pressures are the SAME!!
Which types of patients often have CPAPs?
patients w sleep apnea
where is an endotracheal tube placed?
in the trachea between the vocal cords (pt cannot speak)
what does an ETCO2 monitor measure when a pt is intubated?
ensures there is correct gas exchange occurring; will change colors from purple to yellow to assure correct placement
if an endotracheal tube was placed too deeply, where what you not hear breath sounds?
would not hear sounds on the left; you should hear them bilaterally!
if air is in the stomach, where might the esophageal tube be?
in the esophagus & not the vocal cords!
when a patient is intubated & coughing, what does that often indicate?
a need for suctioning or inappropriate tube placement
when intubating a patient, each attempt should be limited to how many seconds?
30!
what are the goals of mechanical ventilation? list 4
- improving ventilation
- decreasing work of breathing
- correcting inadequate breathing patterns
- improving oxygenation (correcting ABGs & ventilation pH as well)
what are the two ventilator settings & what do they consist of?
- ventilation (PaCO2)
- rate
- tidal volume
- pressure support - oxygenation (PaO2 / SaO2)
- FIO2 (fraction of inspired O2)
- PEEP (positive end expiratory pressure; helps recruit alveoli & keeps them from collapsing assisting w overall gas exchange)
which two ventilator settings affect ventilation & PaCO2 & indirectly affect pH?
tidal volume & rate
describe tidal volume (Vt)
size of each breath; larger breath in = larger breath out
describe rate (f)
number of breaths per minute
- if CO2 is too high, pt will need to breathe faster to blow off access CO2
- if CO2 it too low, patient will be hyperventilating
what are the 3 ventilation modes?
- assist control (AC) (most common)
- synchronized intermittent mandatory ventilation (SIMV) or (IMV)
- pressure support ventilation (PSV)
describe the assist control ventilation mode
either assists a breath or controls a breath
- ventilator delivers a present tidal volume at a preset rat. - the patient will never get fewer breaths than the preset rate
When is the ONLY time the ventilator kicks in & delivered the full present tidal volume to a patient?
ONLY WHEN THE PATIENT TRIGGERS AN ADDITIONAL BREATH
what does it mean when there is a C at the top of an assist control ventilator monitor?
means we are controlling the patient’s breaths & the patient will only be receiving the preset rate & tidal volume
describe the SIMV ventilation mode
ventilator delivers a preset volume at a present rate. in between mandatory breaths, the patient can breathe spontaneously, w a pressure supported breath. however, the tidal volume of the patient-initiated breaths will only be as large as the patient is strong enough to inspire / participate
what do the green & red breaths mean on a synchronized intermittent mandatory ventilation mode?
green breaths = ventilator
red breaths = triggered by patient
what are some advantages of SIMV? list 3
- helps keep respiratory muscles active & coordinated
- can be used as a weaning mode, as the patient improves, the present rate is decreased & the patient assumes greater responsibility for breathing on his / or her own
- if the patient stops breathing for any reason, he / she will still receive the preset volume at the preset rate
what is the purpose of pressure support / PSV?
when on IMV or spontaneous breathing trial, this “boost” from the ventilator increases spontaneous breath volume & makes it easier for the patient to inspire
- meant to overcome the increased airway resistance afforded by the ETT so the patient does not have to work as hard to initiate a breath (facilitates weaning and amount of support is gradually reduced)
describe pressure support
positive pressure to augment patient’s inspiratory efforts; may be used w SIMV or during breathing trial
- may be used as the primary mode of ventilation to overcome resistance of endotracheal tube
what are the 2 settings that affect oxygenation?
- FiO2 (fraction of inspired oxygen)
- PEEP (positive end expiratory pressure)
FIO2 percentage range
30% - 100%
describe PEEP
positive pressure applied at the end of expiration of ventilator breaths
- increases O2 by preventing collapse of alveoli
- maximizes the number of alveoli available for gas exchange
what is PEEP typically set at?
5 cm H2O but can be increased as necessary
if a patient is set at 100% FIO2 but still having terrible ABGs, what would be the next move & why?
increase the PEEP, recruiting more alveoli
what are some complications of PEEP? list 3
- hemodynamic compromise d/t decreased venous return (places pressure on vena cava decrease the amount of blood coming back to the heart)
- volutrauma or barotrauma (high levels of PEEP can damage the causing protein & plasma leakage into the alveoli causing the alveoli to drown)
what symptom may you see R/T high levels of PEEP?
hypotension
if a patient’s ABG results indicate an elevated PaCO2, what changes on the ventilator may be ordered to correct this?
increasing the rate (the faster the patient breathes, the more CO2 you are blowing off)
if a patient’s ABG results indicate a low PaO2, what changes on the ventilator may be ordered to correct this?
increase FIO2
what are potential complications of mechanical ventilation?
aspiration, barotrauma & pneumothorax, ventilator associated pneumonia, decreased cardiac output, decreased fluid balance, immobility, GI problems, muscle weakness, self-extubation & ventilator dependence
what is the purpose of the ABCDEF bundle?
breaks the cycle of over sedation & prolonged ventilation in critically ill patients
what does the ABCDEF bundle stand for?
A - assess, prevent & manage pain
B - both spontaneous awakening trials & spontaneous breathing trials daily
C - choice of analgesia & sedation
D - assess, prevent & manage
E - early mobility & exercise
F - family engagement & empowerment
what should be considered before sedation?
analgesics like fetanul, morphine or Dilaudid
what is the reversal for Fentanyl?
Narcan
what should you monitor in a patient on a continuous IV infusion of Propofol?
hypotension & extravasation (CV cath is preferred)
why does the tubing / bottle of propofol need to be changed every 12 hours?
decreased bacterial growth because it is lipid based
what is a rare complication from propofol? what will you see in the patient?
propofol infusion syndrome, pancreatitis (urine will turn green)
what is dexmedetomidine HCI (Precedex) used for? what should be monitored? how often should this med be titrated?
sedation and often used for alcohol or opioid withdrawal patients; watch for bradycardia & hypotension (resp depression does not occur!) titrate no more frequently than 30 min
what are benzodiazepines used for? what does this put the patient at risk for?
indicated for alcohol withdrawal, prolonged ventilation & increased ICU length of stay, can cause resp depression
what is the reversal agent for benzodiazepines?
Flumazenil / Romazicon
what are neuromuscular blocking agents used for?
(end in UM) used to decrease O2 or metabolic demand in the severely compromised patient
what do you need before administering a neuromuscular blocking agent?
need sedation & pain control!
which type of monitoring is used for sedation? what is the normal range?
BIS monitor; 0-100 (lower the number, means more sedated)
which type of monitoring is used for paralytics?
train four monitor
what number on the BIS would be considered light & moderate?
80 (patient may respond to loud commands & tactile stimuli)
what is the goal for general anesthesia on a BIS monitor?
40-60
what should the peripheral nerve stimulator (train of four) be at prior to starting NMBA or a paralytic?
4/4
what is the most fatal hospital acquired infection?
ventilator associated pneumonia
when is a patient at risk for ventilator associated pneumonia?
when mechanically ventilated for > or equal to 48 hours
how do you prevent ventilator associated pneumonia with checking the pressure of an ET cuff?
checking q shift w a manometer (maintain between 20-25) should not hear gurgling or breathing around the cuff! resp will pump up to the appropriate levels
when should a patient be suctioned to prevent VAP?
suction oropharynx w each mouth care & before turning patient or lying flat
suction before deflating cuff
how do you prevent aspiration?
HOB 30-45 degrees
use sedation as sparingly as possible
verify correct feeding tube placement
consider swallowing eval after prolonged intubation
when suctioning, it should be no greater than ___ mmHg?
120
when there is a high PEAK pressure, what does that mean & what should you do?
possible obstruction (suction)
is the peak pressure
what must the SaO2, FiO2 & Peep levels be at for weaning a patient on short-term ventilation?
SaO2 > 90%
FIO2 50% or less
PEEP 8 cm H2O
explain the differences between IPAP & EPAP
IPAP: bump on inspiration to help patient get an appropriate size of breath or TV
EPAP: PEEP; helps maintain alveoli pressure to help w oxygenation
what must the RR, SaO2, HR & SBP be at for stopping a spontaneous breathing trial?
RR > 35
SaO2 < 90%
HR > 140
SBP > 180 or < 90
explain the differences between BiPAP & CPAP
BiPAP is positive pressure on both inspiration AND expiration
CPAP is continuous positive airway pressure, inspiratory pressure & expiratory pressure is the same
