Question Answer
Define internal respiration (JS) Exchange of gas at the cellular level. (RQ)
Given PIP: 40cmH2O, PEEP: 5cmH2O, Pplat: 32cmH2O, Flow: 55lpm, and Vt of 700ml. Calculate the Raw, Cstat,& Cdyn. Interpret the results. (JS) Raw: 8.7cmH2O/L/sec Normal for intubated. Cstat: 25.9 ml/cmH2O Low-stiff lungs Cdyn: 20 ml/cmH2O Low–stiff lungs (AzQ)
In the presence of bronchospasm, the therapist would expect what change in Raw? (JS) Increase in Raw (ApQ)
What is the difference between compliance and elastance? (AT) Compliance is the ease at which the structure expands. Elastance is the tendency to return to a normal state after being stretched.(RQ)
What are he three types of high-frequency ventilation strategies? What respiratory rates does each one use? (AT) High-Frequency Positive-pressure ventilation 60-100 bpm, High-Frequency jet ventilation 100 and 400 to 600 bpm, High-Frequency oscillatory ventilation 4000 bpm (AzQ)
Convert 6 mmHg to cm H2O (AT) 8.16 cm H2O (ApQ) Page 4
When using a vent, at what speed is a breath delivered? (AB) 30-60 LPM (RQ)
Your pt has a RR of 16 and a Vt of 625ml, what is their VE? (AB) VE= 10Lpm (APQ)
Interpret the following AGB. 7.36/70/65/24 FiO2 100% What can you determine by this ABG? (AB) Acute Resp. Acidosis / pt. may have shunting. (AzQ)
What are the two kinds of PEEP (RK) Intrinsic & extrinsic (RQ)
Calculate for Do2 given the information. Spo2:90 hgb:8 Pao2:60 Qt: 5.5 (RK) 540.54 mL/min (ApQ)
a pt you are caring for has high volumes, high compliance, high resistance, high oxygenation in lung but low in the blood. what is the underlying issue and what vent setting can help (RK) diffusion issue. / increase PEEP (AzQ)
What is the normal range for CaO2 (KH) 18-20% (RQ)
A patient has RR of 35 and a minute alveolar ventilation of 15L what is the tidal volume? (KH) 428.6 ml (Apq)
Define Resistance? (KJ) A measurement of the frictional forces that must be overcome during breathing. (RQ)
Calculate the RAW with the given information. PIP:52cmH2O Pplat: 38cmH20 Flow: 65LPM (KJ) 0.22 cwp/L/sec (ApQ)
Given the patients PaCo2 and PeCos and Vt. Calculate the Vdphys. PaCo2: 55 PeCo2: 40 Vt: 650mL State if this is high/low and why. (KJ) 177.2x RR (16) = 2.8 L/Min This is the amount of deadspace the pt is having, which means there is a diffusion issue (maybe due to excessive secretions, or thickened AC membrane) (AzQ)
Your Pt has an increased Ppeak & an increased Pplateau what is the most likely problem with this Pt? What are possible etiologies of this type of Pt? (NB) The most likely problem is a decreased lung compliance. Some etiologies could be; pulmonary edema, ascities or other abdominal distention, pleural effusion, rt mainstream bronchus intubation. (RQ)
What is the IBW of a spontaneously breathing female Pt who measures 4’8″ and weighs 138lbs? What is her IBW & actual weight in Kg? What will her Vt range be? (NB) {4’8″ F} ht/in 4(12)= 48 + 8= 56in {IBW} 105 + 5 (56-60) = IBW of 85lb {lb/kg} 85/2.2= 38.636 kg (ABW lb/kg} 138lb/ 2.2kg = ABW of 62.72kg {Vt range IBW x 4 to 7} 36.6(4)=146.4ml/kg to 36.6(7)=256.2ml/kg (AzQ)
What is the equation for Vd/Vt? (MC) (PaCO2-PeCO2)/PaCO2=?(MC)
Given the following info what is the Vd/Vt? ABG pH 7.32 PaCO2 76 PaO2 60 Bicarb 25 Venous PvO2 45 PeCO2 48 (MC) (76-48)/76= .36 or 36%
An increase in Vd/Vt represents what? (MC) Shows the % of Vt that is dead space. (MC)
What is the equation for PAO2? (JB) (Pb-PH2O)FiO2-PaCO2(1.25) (JB)
Given normal barometric condition, what is the PAO2 with the following numbers. FiO2- 30% ABG- 7.31/49/60/23 (JB) (760-47).3-49(1.25)= 152.75mmHg (JB)
What does PAO2 represent, and why is this important? (JB) Represents the amount of O2 available in the alveoli. By comparing PAO2 to the PaO2 it can help determine diffusion defects. (JB)
How can you differentiare between a resistance problem and a compliance problem based off of PIP and Pplat? (KM) Resistance promblem: Pplat stays the same and the PIP increases. Compliance problem: Pplat and PIP both increase. (RQ)
Find Cstat and Cdyn given the following: PIP 28, Pplat 19, PEEP 7 and Vt 900. Are they within normal range for someone on mechanical ventilation? (KM) Cstat: 73.3 ml/cwp Cdyn: 42.9 ml/cwp Cstat yes, Cdyn no. (AzQ)
What are 2 things that can cause an increase in VO2? (KM) Exersice, fever (RQ)
What type of ventilation feels like normal breathing? (KH) Negative Ventilation (KH) (RQ)
Calculate the DO2 given CaO2= 12vol%, C.O.=7.6lpm and VO2= 100ml/min. (KH) DO2=912ml/min (KH) (ApQ)
Based on the following information, what is the PAO2 and what does it tell you.. PaCO2=30 FiO2=65% (KH) 425.95mmHg..this is normal..this means the patient has enough O2 in his alveoli for gas exchange. (KH) (AzQ)
Define Functional Residual Capacity. (CG) The volume of gas remaining in the lungs at the end of a normal exhalation. (RQ)
Given: Correct VT 580ml, PIP 45, PEEP 5, PLAT 33. Find Cstat and Cdyn. What does this mean? (CG) Cstat=20.71ml/cwp, Cdyn=14.5ml/cwp; Means a decrease in lung compliance (AzQ)
Pt with PaO2 of 50 on 90% O2. Find and interpret PaO2/FiO2 ratio. (CG) PaO2/FiO2=55.56, ARDS with severe/perminant lung damage (ApQ)
Define ventilation?(TM) Movement of air into and out of the lungs(RQ)
Calculate Vt when RR 16 and VE 7Lpm?(TM) 438ml(ApQ)
What is the normal Alveolar lung volume? (BL) 3/4 of Vt(IBW) (RQ)
What are the two types of Lung Compliance? What are the Normal values of each?(TM) Static 40-60 ml/cmH2O; Dynamic 30-40ml/cmH2O(AzQ)
Given these values, what is the Raw? Is this a normal value? PIP 37, Pplat 22, Flow 47LPM (BL) 11.75cmH2O/L/sec. No it is not within normal range (0.5-2.5cmH2O/L/sec) (AzQ)
What is the IBW of a 5’7 male? (BL) 148lb or 67.3kg (ApQ)
Is normal resistant values greater in an intubated patient or unintubated patient? (MK) intubated (RQ)
Given that a patient (female) is 5’7″ (female) and her Vd is 240, calculate her IBW then calculate her Vd(ant) & Vd(alv). (MK) IBW- 140lbs Vd(ant)- 140ml Vd(alv)- 100ml (ApQ)
If the PIP has drastically increased over the past 4 hours but the Pplat has not, what type of problem is it? And if this is prolonged, what could possibly happen? (MK) RAW hypoventilation, resp muscle failure, respiratory failure (AzQ)
Given a vt of 450ml, PIP of 32, Pplat of 17, PEEP of 7, and a TCF of 4 calculate the Cstat and Cdyn? Are these values normal and what could cause this? (KAH) Cdyn 14 ml/csp Cstat 35 ml/csp Both values are low and could be caused from compliance issues such as consolidation or atelectasis (AzQ)
Given that a 6foot 6inch male, what is his IBW? (MB) 106+6(78-60)= 214lbs (ApQ)
What does VE an abbreviation for?(MB) Total volume of air I/E in 1min. (RQ)
Find the PAO2 for a patient on an FiO2 of 50% and has a PaCO2 of 40 and what does this PAO2 mean for the patient? (MB) I(760-47).5-40(1.25)= 306.5mmHg and this may mean that the pt. is not getting O2 to their alveoli (AzQ)
What happens to our PaO2 as we age? It decreases.
If a patient has a normal dead space of 100ml, what would the patients normal dead space be if they had a trach? 50ml
Interpret the following abg and what could you do to correct it : Ph 7.55 PaCo2 24 PaO2 90 BiCarb 24 acute respiratory alkalosis,decrease RR, breathe in a bag, talk patient down
Which part of the lungs has the highest airway resistance? (BH) Medium Bronchi (RQ)
PIP= 25 Pplat= 15 Flow= 54 Calculate RAW (BH) .19 (ApQ)
Pplat= 31 PEEP= 5 Vt= 500 Calculate Cstat and is it high, low, or normal? (BH) 19.2 ml/cmH2O, low (AzQ)
Define Ventilation. (AH) The process of bringing in fresh air for gas exchange and allowing exhalation of air that contains waste (CO2).
What is the estimated PaO2 for a patient that is 87 years old? (AH) PaO2=105-1/4(87) PaO2=83
Given the following information, what is the PaO2/FiO2 ratio and what does it indicate? PaO2: 60, FiO2: 0.28 (AH) PaO2/FiO2 ratio=60/0.28=214 Ratio of 200-300 indicates Acute Lung Injury. Greater than 300=Normal Less than 200=ARDS
What does a shift to the right on the oxyhemoglobin dissociation curve mean? (AE) Decreased affinity or attraction of O2 to Hb. (RQ)
If the patient has a DO2 of 600 mL/min and a VO2 of 160 mL/min. What does this mean? (AE) The patient has a delivery problem. Caused by a problem with perfusion, diffusion, or low hb. (AzQ)
Calculate minute alveolar ventilation. Vd/Vt= 0.33, RR= 18, IBW= 75.5 kg. (AE) VA= 6012 (ApQ)
What are the pressures that drive ventilation? (Marianne B) Transairway, tramsthoracic, transpulmonary, and transrespiratory pressure. (Recall Question)
Calculate Cdyn: Vt of 800 ml, TCF of 3, PIP of 42, and PEEP of 10. (Marianne B) 22 ml/cwp (ApQ)
Calculate Raw: PIP of 40, Pplat of 20, and a flow 62 LPM. What does that mean for the unintubated patient? (Marianne B) 19.42 cwp/L/sec. There is some pathological condition like asthma. (AzQ)
What does a PaO2/PAO2 ratio of .65 indicate? (RT) O2 is not being transferred to pulmonary circulation. ApQ
Why would negative pressure ventilation not be appropriate. (RT) High Raw and and low compliance. RQ
What happens to resistance and compliance if you have pulmonary edema? (RT) Resistance increases, compliance decreases. AzQ
You have a Pt with a RR-17 Vd Phys of 420ml & Vd al 270ml Calculate the Vd Phys (min)? How much does your Pt weigh in lb? What is your Pt’s Vd anat.? What are some reasons a Pt’s Vd alv may be this high? -NB Vd phys (min)= 7.14 L 420ml x 17 = 7140/1000 = 7.14L Pt’s weight in Lb’s= 150lb 470ml – 270ml = 150ml (Vd anat) 150ml= 1ml/lb = 150lb Vd anat= 150ml (see above) Reasons for high Vd alv= consolidation, atelectasis etc. (ApQ)
What is mouth pressure? (RQ)-(CZ) Mouth pressure is the airway opening pressure aka airway pressure. Unless pressure is applied at the airway opening this pressure is zero or atmospheric pressure
What is your respiratory rate when with a minute ventilatory rate of 6 lpm and a tidal volume of 500 ml? (ApQ) -(CZ) The RR would be 12 breaths per minute.
If the patient has a corrected tidal volume of 650, a PIP of 35, and a PEEP of 5, what will the dynamic compliance be? Is this in the normal range? Will this take into account RAW or deadspace? (AzQ)-(CZ) Dynamic compliance: corrected Vt/PIP-PEEP. 650/35-5= 21.66 mL/cwp. This is not normal. It does take into account RAW.
What are the risks of ABG’s? (JM RQ) Infection, hemorrhage, lose of limb, pain, nerve damage, emboli, rupture, or damage to artery wall.
What type of hypoxia is due to decreased cardiac function? What would their cardiac output, HR, and BP look like? (JM AzQ) Circulatory hypoxia. They would decrease.
Figure out the Vd/Vt for the following pt: PaCO2 = 50 PeCo2 = 19 Does this pt need treatment? (JM ApQ) Vd/vt is 62% pt is critical and needs immediate intervention.
Define external respiration. (JB) The exchange of O2 and CO2 between the alveoli and the pulmonary capillaries.
Given DO2 of 1000ml/min and VO2 of 250ml/min, What is the SvO2? Why do we need such a large SvO2? (JB) 750ml/min, to allow for sustained fight or flight response (stimulation of sympathetic system)
Given RR 12, VE 7.2Lpm, TCF 3, PIP 20cmH2O, Plat 15cmH2O, PEEP 5cmH2O. What is the corrected Vt? (JB) 555ml
What does increased PIP and increased Pplat signify? (JoeB) Increased tidal volume and Decreased pulmonary compliance.
Find the RR and VE if the VA is 12.0L, Vt is 930ml, and VD/VT is 19%. (JoeB) RR = 16 VE = 14.88L
List 4 caused of increased airway resistance. (JoeB) Secretions, foreign body aspiration, bronchospasm, airway compression…
What is external respiration? (AL) Involves the exchange of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries.
Calculate the amount of pressure needed to attain a tidal volume of 0.5L (500 ml)for a patient with a normal respiratory system compliance 0.1 L/cm H2O. (AL) C=change in volume/change in pressure. .1 L/cm H2O=.5L /pressure. Pressure x .1=.5 Pressure=.5/.1=5 cmH2O
What accessory muscles are used during expiration? (AL) Rectus abdominus, External oblique, Internal oblique, Transverse abdominal, Serratus (anterior, posterior), Latissimus dorsi
Question Answer
Scalars or variables used in vent graphics? Pressure, flow, & volume graphed over time
Pressure is measured in? cmH2O
Time is measured in? seconds or minutes
Flow is measured in? L/m
Volume is measured in? mL or Liters
Where will you find the Ordinate & the Abscissa? Y axis & X axis
When is the rate of change the greatest? Beginning of the event
When is the rate of change the smallest? End of the event
Time constants are influenced by: Changes in vent settings (flow, pressure, Vt), total rate, compliance, & resistance
Short time constant implies: A fast rate of change
Long time constant implies: A slow rate of change
Benefits of short I-time: Allows for longer E-time, reduces risk or occurrence of auto-PEEP, promotes venous return
Disadvantages of short I-time: Promotes greater flow turbulence, reduces alveolar ventilation, promotes higher peak airway pressures
Benefits of short E-time: None
Disadvantages of short E-time: May reduce venous return & cardiac output, drop BP, promotes Auto-PEEP
Benefits of long I-time: Can improve PaO2, diffusion time is extended
Disadvantages of long I-time: Shortens E-time = can reduce venous return, may compromise cardiac output, patient can’t exhale sooner
Benefits of long E-time: Promotes venous return, reduces Auto-PEEP
Disadvantages of long E-time: Odd breathing pattern – pt may want to take a breath sooner but can’t
Factors that influence waveforms: Compliance, resistance, flowrate, rate (bpm)
Problems associated w/ reduced compliance: Atelectasis – collapsed alveoli, Lung collapse – pneumothorax
Causes for loss of lung compliance: ARDS, atelectasis, pneumo, fibrosis, pneumonia, P.E., mainstem intubation, pleural effusion, gastric distension, ascites
Iatrogenic causes of compliance loss: High PEEP/CPAP settings, high Vt, high pressure, high FiO2 resulting in nitrogen washout
Acute causes of resistance: airway secretions, bronchospasm, biting E/T tube, kinked E/T tube, aspiration of foreign body (usually during trauma)
Chronic causes of resistance: Airway edema, mucus migration into E/T tube, plugged filters, overly wet HME’s
Benefits of low flow rates: Lower airway pressures, improved gas distribution, long I-time = improved oxygenation
Possible problems with low flow rates: Extended I-time = smaller E-time = possible auto-peep and reduced venous return
Question Answer
What are the three indications for mechanical ventilation? Ventilatory Failure oxygenation Failure Prophylactic Ventilatory Support
What is the sandard criteria for instituting mechanical ventilation? Apnea or absence of breathing Acute Respiratory Failure Impending Respiratory failure Refractory hypoxemia w/ increased WOB or ineffective pattern
What is the criteria for acute ventilatory failure? An increase of PaC02 >50 mm Hg with an accompanying respiratory acidosis (pH <7.25)
What is the criteria for impending ventilatory failure? Patient can maintain or marginally maintain normal ABG, but at the expense of significant WOB. PaC02 will trend upward.
What are assessments that can indicate impending ventilatory failure? Tidal volume Respiratory Pattern Minute Ventilation Maximul inspiratory Pressure Vital Signs
What can be a secondary complication ventilatory failure? Hypoxemia
What is oxygenation failure defined as? Severe hypoxemia that does not respond to moderate to high (>60%) supplimental oxygen.
Oxygenation failure is not a direct indication for mechanical ventilation “BUT” mechanical ventilation is needed to support WOB associated with oxygenation Failure
Mechanical ventilation is indicated typically if the Pa02 is <70mm Hg on 60% fi02 or <40 mm Hg on any fi02. P(A-a) of > 450 mm Hg on 100% fio2
Prophylactic ventilatory support is provided in clinical situations where there is risk of pulmonary complications ventilatory failure oxygenation failure is high
Prophylactic ventilatory support reduces risk of pulmonary complications risk of hypoxia on major organs WOB and oxygen consumption Cardiopulmonary stress
Hyperventilation therapy (blowing of c02) decreases ICP
What are the three conditions leading to mechanical ventilation? Depressed respiratory drive Excessive Ventilatory Workload Failure of Ventilatory Pump
Depressed Respiratory Drive (CNS) can include drug overdose, acute spinal cord injury, head trauma, neurologic dysfunction, sleep disorders, metabolic alkalosis
Excessive Ventilatory Workload (CNS) can include acute airflow obstruction, deadspace ventilation, acute lung injury, congenital heart disease, cardiovasuclar decompensation, shock, increased metabolic rate, drugs, decreased complaince
Failure of ventilatory Pump (NM/WOB) can include chest trauma, premature birth, electrolyte imbalance, geriatric patients
What is the absolute contraindication for mechanical ventilation? Untreated pneumothorax
What are three relative contraindications for mechanical ventilation? Patients informed Request Medical Futility Reduction or termination of patient pain and suffering.
What are hazards of mechanical ventilation related to positive pressure ventilation? Barotrauma, hemodynamic instability, increased ICP, oxygen toxicity
What are hazards of mechanical ventilation related to patient condition? infection, multiple organ failure
What are hazards of mechanical ventilation related to equipment Ventilator or alarm malfunction, circuit disconnection, accidental extubation, endotracheal tube blockage, tissue damage, atelectasis
What are hazards of mechanical ventilation related to medical professionals? Nosocomial Infection, Inappropriate settings
What are 2 things that affect the work of ventilatory muscles? Compliance Resistance
Compliance is defined as the elastic forces of the lung
Compliance is indirectly proportional with ventilatory work
compliance is directly porportional to amount of volume inhaled
Resistance is defined as the force that must be overcome to move gas in and out of the lung
resistance is directly proportional with ventilatory work
Resistance is indirectly proportional to amount of voulume inhaled
Poiseuilles Law goes along with resistance and states that there is a 16 fold increase in airway resistance when the radius of the airway is decreased by half.
What is the definition of a ventilator? A machine/device that can fully or partially substitute for the ventilatory work.
What are the 2 types of ventilators? Negative Pressure Ventilators Positive Pressure Ventilators
The iron lung encloses patient in tank except for the head and neck and works by evacuating air to produce a negative pressure around the chest, which is transmitted to the lung.
The greater the negative pressure the greater the? volume moved into the lung
What is andvantage of the iron lung? noninvasive
What are some disadvantages to the iron lung? Poor Patient Access decreased cardiac output (tank shock) Requires added oxygen therapy
The Chest Cuirass is also known as the turtle shell
Why was the chest cuirass created? To improve patient access and minimize tank shock
The chest cuirass covers the chest only and must have? an airtight seal between shell and chest wall
The chest cuirass works similar to the iron lung in that it generates a negative pressure that is transmitted to the lung
What is the advantage of the chest cuirass? It’s noninvasive
What are disadvantages to the chest cuirass? An airtight seal between patient and shell is difficult. Requires added oxygen therapy
What are four physical characteristics of a mechanical ventilator? Power source/ input power type of ventilator power transmission and conversion system. Control systems and circuits
The power source or input power can be pneumatic, electrical or both “built in” batteries/air compressors
The type of ventilator can be either Negative or positive pressure
In regards to the power transmission and conversion system the drive mechanism is the mechanism by which the ventilator transmits or converts the input power to useful ventilatory work.
The Control panel is also known as the user interface
The control pannel allows for the ability to manipulate pressure, volume, and flow; controls the drive mechanism
The pneumatic circuit is double lined and recognizes settings and sends signals
Control variable corresponds with the ventilator class
Pressure controller pressure does not change as a result of compliance and resistance changes
Volume controller volume does not change as a result of compliance and resistance changes
A volume controller ventilator class measures volume directly
A time controller ventilator class is whereby pressure, volume, and flow change as compliance and resistance changes.
In a time controller ventilator class time is constant
In a flow controller ventilator class volume does not change as a result of compliance and resistance changes
in a flow controller class volume is measured indirectly by measuring flow
What is the average bias flow? 6 lpm (flow that’s always in the circuit)
Phase 1 change from expiration to inspiration
Phase 2 inspiration
Phase 3 change from inspiration to expiration
Phase 4 Expiration
The trigger variable corresponds with Phase 1 and triggers (starts) breath delivery
The limit variable coressponds with phase 2 and Is the variable not exceeded above the preset value during inspiration.
It is important to note that inspiration does not end when the variable reaches the preset value
The Cycle variable corresponds with phase three and is the variable that cycles (stops) the breath delivery)
Expiration is Passive and corresponds with phase 4
Ventilator Alarms can be visual audible both
Input Power alarms warns loss of electrical or pneumatic power
Control Circuit Alarms Warns that settings are not acceptable or that ventilator has failed some part of self-diagnostic test
Output (patient alarms) Warns of problems with pressure, volume, flow, time, fi02, or circuit temperature problems
Respiratory cycle time can also be called Total Cycle Time
Respiratory cycle time is calculated as 60/Frequency