Mechanical Ventilation Flashcards

Plateau Pressure
Terms Definitions
failure to oxygenate
Inadequate Oxygenation
Central cyanosis
Accessory muscle use
nasal flaring
What is normal SvO2?
Apnea Alarm
Ventilator disconnected from patient
Tubing disconnected along circuit
Patient is apneic
Enter your back text here.
What causes refractory hypoxemia?
Intrapulmonary shunting
What causes coarse crackles?
Excessive secretions
Inadequate Ventilation
Rising arterial CO2
Chest abdm asynchrony
irrgular respirations
T/F: a pt. on synchronized intermittent mandatory ventilation can take spontaneous breaths
Nondepolarizing Agents
Enter your back text here.
Diffusion Defect
Pathologic condition leading to impaired gas exchange through the alveolar-capillary membrane.
What is the Minute Alveolar Ventilation formula?
Initiation of a mechanical breath based on the set time interval for one complete respiratory cycle (inspiritory time and expiratory time).
Below normal level of alveolar ventilation characterized by an elevated PaCO2
Is Plateau Pressure attributed to compliance or airway resistance?
Volume Cycled
ventilator delivers a preset tidal volume, the allows for passive expiration
Most common in critical care setting
Advantage: Patient is guaranteed to receive a preset tidal volume under normal operating conditions.
Disadvantage: Peak inspiratory pressure (PIP) may increase to levels high enough to cause barotrauma or damage to healthy alveoli
Controlled trials in pts. with diffuse lung disease have shown that _______ tidal volumes are associated with increased survival
Fluidic switches are also known as this.
Xanthine Bronchodilators
Drugs that produce bronchodilation by inhibiting phoshpodiesterase, an enzyme that activates cyclic 3'5 AMP.
Deadspace Ventilation
Ventilation in excess of perfusion; wasted ventilation.
What is another name for Pulmonary Artery Catheter?
Pumping strength of the heart. Contractility may be increased by improving the blood volume or by positive inotropic medications.
What measurement reflects the elastic properties (elastic resistance) of the lung and chest wall?
Static Compliance
Anatomic Deadspace
The volume occupying the conductiong airways that does not take part in gas exchange. Estimated to be about 1 mL/lb ideal body weight.
Reducing Valve
Adevice that decreases the delivery pressure of a gas.
What type of bacillus is TB?
Acid Fast
Interhospital Transport
Moving a patient between two hospitals.
Does PEEP increase or decrease venous return and cardiac output?
What is the strongest stimulus for blood flow in the brain?
High Pressure alarm
Kink in vent tubing
Secretions in ETT/airway, or condensation in tubing
Patient coughing, gagging, or biting ETT
Increased airway pressure from bronchospasms or pneumothorax
Patient trying to talk
what is PEEP?
a ventilatory maneuver in which positive pressure is applied to the airway during exhalation
Define Total Parenteral Nutrition.
Complete nutritional support provided to the patient by any method (usually intravenous) other than the intestinal route.
Define PEEP
Positive End Expiratory Pressure is an airway strategy in ventilation that increses the end expiratory or baseline airway pressure to a value greater than atmospheric pressure.
Ventilatory Failure
Failure of the lungs to eliminate carbon dioxide. Without supplemental oxygen, it leads to hypoxemia.
Pulmonary Artery Pressure
Pressure measured in the pulmonary artery. It reflects the volume status of the pulmonary artery and the functions of the ventricles. Right ventricular afterload.
What is prone positioning?
Placing a patient face down.
What is a normal percentage of anatomic deadspace?
30 percent
Plateau Pressure
The pressure needed to mainatian lung inflation in the absence of air flow.
Total Parenteral Nutrition (TPN)
Complete nutritional support provided to the patient by any method (usually intravenous) other than the intestinal route.
Intrapulmonary Shunting
Pulmonary blood flow in excess of ventilation; wasted perfusion (e.g. atelectasis). Causes refractory hypoxemia.
Oropharyngeal Airway
A device to relieve upper airway obstruction in a sedated or unconcious patient.
What helps hypoxemia caused by pulmonary shunting?
PEEP and oxygen
Should the chest tube be placed higher or lower than the patient during transport?
What is time-triggered?
Initiation of a mechanical breath based on the set time interval for one complete respiratory cycle (inspiritory and expiratory time).
When a patient is on a ventilator, what is the effect of too little food?
Describe PEEP
- Mode
- Applies positive pressure on expiration to keep alveoli open
- 5 cm H2O can be higher in less compliant lungs (ARDS)
How can synchronized intermittent mandatory ventilation lead to prolonging of the weaning process?
Requires continually turning down ventilator rate-->exercises respiratory muscles during spontaneous breaths but can cause diaphragmatic fatigue
PaCO2 is the best indicator for?
alveolar hyperventilation and hypoventilation
Does CO2 act as a vasoconstrictor or a vasodilator in cerebral blood vessels?
What determines the detrimental effects of PEEP?
Enter your back text here.
Chamber three in a three chamber chest tube drainage system is also called?
Suction Chamber
Refractory Hypoxemia
Low oxygen tension in the blood that responds very poorly to oxygen therapy.
Another name for the PNA you can get with AIDS
What P/F ratio is normal for critically ill patients?
Less than 200
Define refractory hypoxemia.
Low oxygen tension in blood that responds very poorly to oxygen therapy.
Lung Compliance
The degree of lung expansion per unit of pressure change.
How is anatomic deadspace determined?
1mL/lb of ideal body weight.
Where should the high pressure alarm be set?
5-10 above PIP
What P/F ratio indicates shunting is likely?
More than 200
What chemical is used to clean a bronchoscope?
Ethyline Oxide
An ester that plays a role in the transmission of nerve impulses at the synapses and neuromuscular junctions. Metabolized by an enzyme. Too much or too little can lead to muscle blocade.
If pressure rises to a preset level and is maintained at that level until inspiration ends, this is termed a:
Pressure Limit
What does PEEP do to CVP and PAP?
Increases them.
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Define positive pressure ventilation.
Mechanical ventilation in which the volume is delivered by a positive pressure gradient, airway pressure is higher than alveolar pressure.
What are some possible complications with mechanical ventilation?
1. Airway obstruction
2. Pulmonary Infection
3. Tissue trauma
4. Atelectasis
5. Mechanical vent malfunction
6. Tension pneumothorax
7. Skin breakdown
8. O2 toxicity
Pressure control ventilation-->what flow is delivered by ventilator?
Whatever flow is required to achieve preset pressure
when is syncronized intermittent mandatory ventilation used?
in continuous ventilation and during weaning from ventilator
What is a cycle?
The length of one complete breathing cycle.
How is the Bronchoscope inserted?
Nare, Mouth, Trach tube or Endotracheal tube
Renal Perfusion
Blood flow to the kidneys. It is decreased when blood volume or cardiac output is low.
How do you calculate pulse pressure?
Systolic Pressure - Diastolic Pressure
Define Oxygenation failure
Failure of the heart and lungs to provide adequate oxygen for metabolic needs.
Synchronized Intermittent Mandatory Ventilation (SIMV)
A mode in which the ventilator delivers control (mandatory) breaths to the patient at or near the time of a spontaneous breath. The mandatory breaths are synchronized with the patient's spontaneous breathing efforts so as to avoid breath stacking.
Does the top or the bottom of the P-V loop bow out with increases in expiratory resistance?
Mandatory Minute Ventilation (MMV)
A feature of some ventilators that causes an increase of the mandatory rate when the patient's spontaneous breathing level becomes inadequate. This compensation by the ventilator ensures a safe minimal minute ventilation.
What causes Metabolic Acidosis in the presence of a normal anion gap?
A loss of base.
Chamber two in a three chamber chest tube drainage system is also called?
Water Seal Chamber
Define Peak Inspiratory Pressure (PIP).
Maximum pressure measured during one respiratory cycle, usually at the end of inspiration.
What does PAP reflect?
The volume status of the pulmonary artery and the functions of the ventricles. Right Ventricular Afterload.
Is pressure control ventilation a "triggered" mode of ventilation?
No-->pt. doesn't control the tidal volume or rate
what is positve pressure ventilation?
where the ventilator pushes air into the lungs under positive pressure (which raises intrathoracic pressure during inspiration)

expiration is passive
explain the indications for weaning while looking at
a. spontaneous RR
b. spontaneous tidal volume
c. minute ventilation
d. negative inspiratory force or pressure?
a. spontaneous RR: LESS than 38/min

b. spontaneous tidal volume: MORE than or equal to 5ml/kg (NORM 7-9)

c. minute ventilation: LESS than or equal to 10L/min (NORM 5-10)

d. negative inspiratory force or pressure?: MORE than neg 20 H20 (more neg, the better)(NORM neg 20)
What is the thoracic pump mechanism?
Alternations in pulmonary blood flow caused by changes in intrathoracic pressure during positive pressure ventilation.
What is a reducing valve?
A device that decreases the delivery pressure of a gas.
What are contributing factors to auto-PEEP?
Air trapping and low inspiratory flow.
How much urine should be produced per hour?
At leaset 60 ml
How many blood samples does the estimated physiologic shunt equation require?
One, an arterial blood sample
Proportional Assist Ventilation (PAV)
A mode of ventilation that changes the pressure support level according to the volume, elastance, airflow resistance and flow demand.
What does the shift of the slope toward the volume axis on a loop graph indicate?
An increase in compliance.
What is the range for transport by Propeller driven aircraft?
100 to 200 miles
Where does resistance come from in COPD?
Emphysema, Chronic Bronchitis, Asthma and Bronchiectasis
What is a trigger?
What causes an inspiration to begin on a vent.
How many times harder is the work of breathing for a COPD patient compared to a normal patient?
10 times greater.
What is maximum inspiratory force (MIF)?
The amount of PRESSURE generated by the pt. during inhalation
when is weaning carried out?
during the day (pt is ventilated at night)
What is Pulmonary Capillary Wedge Pressure?
Pressure measured in the pulmonary artery with a balloon inflated to stop pulmonary blood flow.
What regulates I:E ratio?
The inspiratory flow rate, I time or E time.
What does a decrease in SvO2 indicate?
Hypoxemia, decrease in CO, increased tissue demand for O2
Impending Ventilatory Failure
A gradual increase of PaCO2 ( > 50 mm Hg) caused by decreasing lung functions.
Laryngeal Mask Airway (LMA)
A tube with a small cushioned mask on the distal end that provides a seal over the laryngeal opening. With proper care and sterilization, it can be used up to 40 times. Size 4 for Females and 5 for Males.
Calculation for Anion Gap with K+
(Na + K) - (Cl - HCO3)
How does airway resistance variy with the length and width of the ET tube?
resistance varies directly with the length and inversely with the width of the ET tube.
what are the two types of positive pressure ventilators?
volume and pressure ventilators (the name tells you what the endpoint of the push is, ie. a volume ventilator will stop at certain volume)
what do you need to monitor to determine readiness to wean? (5)
1. degree of shunt
2. vital capacity
3. mVV
4. inspiratory force
5. FEv1
What does Pulmonary Capillary Wedge Pressure reflect?
The volume status and functions of the left heart. Left ventricular preload.
What does increased bowing out of the P-V loop suggest?
An overall increase in airflow resistance.
What happens to PIP and Plateau pressures when airflow resistance is increased?
PIP is increased and Plateau Pressure remains the same.
what is needed in inverse ration ventilation and why?
pt needs to be sedated b/c inverse ratio ventilation imposes a not normal breathing pattern
Does pure shunt respond to oxygen therapy?
No, Pure shunt is refractory to oxygen therapy.
How does hypoperfusion of the kidneys affect drug concentration in the circulation?
May lead to a higher drug circulation in the circulation.
No fluctuation in the chest tube may indicate? (4)
1. the tube is obstructed
2. if a dependent loop exists
3. if the suction is not working properly
4.the lung has reexpanded
What is the definition of Lung Compliance?
The degree of lung expansion per unit of pressure change.
What happens to Blood Pressure and CO2 when positive pressure is put into the lungs?
Blood pressure will fall and CO2 will decrease.
What are the ranges for hypoxemia?
Normal is 80 to 100 mm Hg, Mild is 60 to 79 mm Hg, Moderate is 40 to 59 mm Hg and Severe is less than 40 mm Hg
four cycling mechanisms
T/F: synchronized intermittent mandatory ventilation is synonymous with partial mechanical ventilation
Hypo/Hyperventilation breakpoint for Dr. Miller for normal patients.
_______ peak inspiratory pressures promote barotrauma
This mode provides time-triggered, PRVC breaths when prolonged apnea is detected (12, 8 and 5 sec in adult, pediatric and neonatal modes respectively).
Unintentional PEEP associated with pressure support ventilation, rapid respiratory rates, slow inspiratory flow and air-trapping.
Adequate Oxygenation
PaO2 within desired range
Regular respirations
Stable hemodynamics
Symmetrical anterior chest expansion
adequate depth, timing, and rhythum
Pressure control ventilation-->flow determined by pt. or preset?
Determined by pt.
Narcotic Analgesics
Enter your back text here.
Normal CPP Range
Between 70-80 mm Hg
Termination of the inspiratory cycle when the preset volume is reached.
V/Q Mismatch
An abnormal distribution of ventilation and pulmonary blood flow. High V/Q is related to deadspace ventilation whereas low V/Q is associated with intrapulmonary shunting.
What is the minimum acceptable MAP?
True/False: As the sensitivity number is decreased the sensitivity of the ventilator is decreased.
Describe T-piece
- Set FiO2
- Pt. breaths spontaneously
- Not connected to vent
Tidal volumes of normal, spontaneous breathing
6-8 ml/kg
What phenomenon governs fluidic switches?
The Coanda Effect
Sympathomimetic Bronchodilators
Adrenergic agonists, Drugs that dilate the airways by stimulating the beta-2 receptors of the sympathetic nervous system. Includes epinephrine and albuterol.
Blind Intubation
Insertion of an artificial airway without use of a visual aid.
Pulse Oximeter
A device that estimates arterial oxygen saturation (SpO2) by emitting dual wavelengths of light through a pulsating vascular bed.
Formula for SVR
((MAP - RAP) x 80)/CO
The length of one complete breathing cycle.
What is the normal K+ Concentration?
4 mEq/L
Causes inspiratory crackles
Lung consolidation and Pulmonary Edema
Complications of Bronchoscopy
Infection, V/Q Mismatch, Hemorrhage and Pneumothorax, Hypoxemia and arhythmias are the two most common.
What is characterized by an increase in PaCO2?
Define hepatic perfusion.
Blood flow to the liver.
Define Renal Perfusion.
Blood flow to the kidneys.
Controlled mechanical ventilation-->define in terms of tidal volume and rate
preset tidal volume delivered at specified rate, regardless of pt. status
pt can breathe faster/slower on assist control ventilation?
faster only
Does the setting of the wall vacuum and the amount of bubbling in Chamber 3 reflect the level of suction applied to the pleural space?
What is an absolute contraindication for Mechanical Ventilation?
Tension Pneumothorax
Airway Resistance
The degree of airflow obstruction in the airways.
How do we defeat shunt on a spontaneously breathing patient?
Hemoglobins that do not carry oxygen. In the prescence of dyshemoglobins, pulse oximeter reads higher than actual SaO2.
Name two causes of V/Q mismatch.
Deadspace and shunt
Gastrointestinal (GI)
Organ system including the stomach and intestines.
The mechanism that provides a mode of ventilation within a specific parameter (pressure, time, volume or flow).
Eucapnic Ventilation
The amount of ventilation needed to bring the patient's PaCO2 to normal.
What is REE?
Minimum energy requirement for basic metabolic needs
Hemodynamic Monitoring
Measurement of the blood pressure in the vessels or heart chambers during contraction (systole) and relaxation (diastole).
Two drugs given for sedation before/during a bronchoscopy.
Morphine and Diazepam
Define anatomical deadspace.
The volume occupying the conducting airways that does not take part in gas exchange. Estimated to be 1mL/lb of ideal body weight.
Which could be worse for the lungs, PEEP or CPAP?
Mechanical Ventilation
Patient is attached to a machine to breathe
How does PEEP predispose to barotrauma?
Elevates overall airway pressure-->barotrauma is caused by air rupturing into bronchovascular bundle, tracking back to mediastinum, then into pleural space (pneumothorax) or into subcutaneous tissues (subcutaneous emphysema)
for positive ventilation, what do you need to pay attention to as to prevent unplanned hyperventilation or hypoventilation?
the tidal volume
What Non-Mechanical Factors can lead to muscle fatigue?
Malnutrition, Endocrine diseases, electrolyte disorders, drugs, persistent hypoxemia.
Common Indications for chest tube
Pneumothorax above 25%, Hemothorax, Pleural Effusion
Do you need an order to move a patient?
Intra-abdominal Pressure (IAP)
Pressure measured by a transducer via a transurethral bladder catheter.
What is the Compliance Formula?
Enter your back text here.∆V/∆P
What Minute Volume limit produces Respiratory Failure if breached?
10 L or above
Alveolar Deadspace
The normal lung volume that has become unable to take part in gas exchange because of reduction or lack of pulmonary perfusion. I.E. Pulmonary Embolism.
What makes compliance data most useful?
If it is trended.
Maximum Inspiratory Pressure (MIP)
Also called negative inspiratory forse (NIF), it reflects a patient;s respiratory muscle strength. MIP of less than 20 cm H2O is one of the indicators of impending ventilatory failure.
Optimal PEEP
The lowest PEEP level leading to the best oxygenation or compliance status without causing cardiopulmonary side effects.
What is normal Pulmonary Vascular Resistance?
50 to 150 dynes.sec/cm5
Chest Tube Size for small adults and teens
28-32 French
What is a servo?
A feedback system that typically consists of a sensing element, an amplifier and a servo-motor, used in the automatic control of the mechanical device of a ventilator.
Elevated intraabdominal pressure transmits excessive pressure across the diaphram to the heart and great vessels. What does this result in?
Decreased cardiac output and decreased renal perfusion.
Describe Synchronized Intermittent Mandatory Ventilation (SIMV)
- Used as weening technique
- Preset FiO2, Vt, and RR but synchronized with pt.'s RR
- Pt. can breath above preset rate and determine own Vt
- As RR is decreased the pt. increases spontaneous breathing
Pressure support ventilation-->how long is gas flow maintained?
As long as pt. continues to inspire
how does PEEP help breathing?
1. it increases functional residual capacity
2. restroes lung volume that normally remains at the end of passive exhalation
The primary forces that the ventilatory muscles must overcome include:
Resistive forces and Elastic Forces.
Operative Tube Thoracostomy
A technique of chest tube placement by dissection inot the pleura, digital inspection of the pleural space and insertion guided with the finger and a hemostat.
What is the formula for static compliance?
Plateau Pressure - PEEP
Define alveolar deadspace.
The normal lung volume that has become unable to take part in gas exchange because of reduction or lack of pulmonary perfusion. (eg. pulmonary embolism).
Peak Inspiratory Pressure
The pressure used to deliver the tidal volume by overcoming non-elastic (airways) and elastic (lung parenchyma) resistance.
What do most normal people have as a shunt percentage?
5 percent
Continuous Positive Airway Pressure (CPAP)
The end-expiratory pressure applied to the airway of a spontaneously breathing patient.
Intracellular Fluid (ICF)
Fluid within the cells. It accounts for 40% of total body water.
4 reasons to monitor patients on Ventilators
Establish baseline measurement, establish trends, modify treatment plan, set proper alarm limits
What is the range for transport by Ground Ambulance?
Under 150 miles
What example did Dr. Miller say is best representation of a ventilator?
A fireplace bellows
What is intraabdominal pressure?
Pressure measured by a transducer via a transurethral bladder catheter.
What are tidal volumes on mechanical ventilators set at higher volumes than normal tidal volumes?
Subjectively more comfortable, helps to prevent microatelectasis that results from monotonous small tidal volume ventilation
what is happening in pressure ventilators?
peak of respriatory pressure is predtermined and tidal volume delivered to pt varies

(TIDAL VOLUME CHANGES/not consistent)
explain negative pressure ventilator? (3)
1. most similar to normal physiologic ventilation
2. applied to outside of body
3. freq used at home for neuromuscular disease or nervous system d/o
when on the weaning trial, what s/s may indicate stopping the trial and ventilating again? (9)
1. tachypnea
2. dyspnea
3. tachycardia
4. dysrhythmia
5. desat of sp02 of less than 91%
6. hypotension/hypertension
7. agitation/anxiety/changes in lOC
8. sweating
9. sustained tidal volume of less than 5 ml/kg
What is oxygen delivery a product of?
O2 content and cardiac output.
What is a solenoid valve?
A valve controlled by an electronic switching device that is used to regulate the specific functions of a ventilator.
Volume-Assured Pressure Support (VAPS)
A mode of ventilation that assures a stable tidal volume by incorporating inspiratory pressure support ventilation (PSV) with conventional volume-assisted cycles (VAV).
What can severe K+ depletion lead to?
Metabolic Alkalosis and Compensatory Hypoventilation
What percentage of shunt is considered significant?
20 to 30 percent shunt
Positive end-expiratory pressure (PEEP)
PEEP is an airway pressure strategy in ventlation that increases the end-expiratory or baseline airway pressure to a value greater than atmospheric pressure. It is used to treat refractory hypoxemia caused by intrapulmonary shunting.
Conversion from kPa to cm H2O
kPa x 10 = cm H20
Why is diagnostic bronchoscopy done?
To gather additional information or to confirm preliminary diagnosis following history, physical and other lab results.
What percentage of shunt is considered mild?
10 to 20 percent shunt
What is the formula for cardiac output?
Heart rate X Stroke Volume
Describe Pressure Support (PS)
- Set FiO2
- No set Vt or RR
- Positive pressure is supplied during inspiration while pt. sets or RR and Vt
- Can be used to ween
- Measured in cm H2O
where would you first check for site of disconnection between mechanical ventilators b/c it is the most common?
between tracheal tube and adapter
What Mechanical Factors can lead to muscle fatigue?
High airway resistance, Low lung compliance and Low chest wall compliance
Airway Pressure Release Ventilation (APRV)
A mode of ventilation in which the spontaneous breaths are at an elevated baseline (i.e. CPAP). This elevated baseline is periodically "released" to facilitate expiration.
What factors can make a Pulse Oximeter measure lower than actual SaO2?
Sunlight, nail polish, fluorescent light, intravenous dyes
Acute Ventilatory Failure
An increase of PaCO2 ( >50 mm Hg) with a concurrent decrease of arterial pH (pH
When do we use inverse ratio ventilation (IRV)?
Improving oxygenation in patients with ARDS.
For critically ill patients, what is the clinical range for dynamic compliance?
Between 30 and 40 mL/cm H2O
What are some signs of neurological impairment?
Headache, mental status changes, motor disturbances and ocular abnormalities.
what is the progression of mechanical ventilation types for a pt coming off support?
control assist -> weaning mode like volume support -> CPAP
what are s/s of unplanned extubation? (5)
1. pt talking
2. activation of low pressure ventilator alarm
3. diminished or absent breath sounds
4. respiratory distress
5. gastric distension
What happens to blood flow in hypotensive conditions during positive pressure ventilation due to the thoracic pump mechanism?
Decreases blood flow to the left heart.
How many blood samples does the classic physiologic shunt equation require?
Two, an arterial blood sample and mixed venous blood sample.
in pt with normal v/q perfusion rates, what can be used as an estimate of paco2? how do you measure?

PETCO2 usually 1 to 5 mmHG lower than PaCO2
How does a decrease in tidal volume affect anatomic deadspace?
It causes a higher anatomic deadspace to tidal volume percentage.
What can cause an inability to reach PIP?
ET tube cuff leak and/or Ventilator circuit leak.
what kind of pt do you have to be careful when giving CPAP to? why?
pt with myocardial compromise

b/c it increase the work of breathin since the pt has to FORCEFULLY exhale against CPAP
What is the minute volume formula?
VA = f(Vt-Vd) or VA = (Vt-Vd) x RR
How can PEEP lead to areas of the lung not being perfused?
Can cause so much compression of capillary bed that have areas where intraalveolar pressure exceeds capillary pressure-->this usually happens in non-dependent lung zones where hydrostatic capillary pressure is lowest
Affecting the contraction.
Alveolar-arterial Oxygen Pressure Gradient
Pressure control ventilation-->is rate preset or controlled by pt.?
Formula for RSBI
RR/Vt (in liters)
Enter your back text here.
T/F: in pressure support ventilation, the pt. determines the inspiratory flow rate
with ECMO, waht is required?
systemic anticoagulation
One Torr CO2 changes pH by?
Forceps Biopsy
Enter your back text here.
speech problems
Difficulty due to timing with ventilator cycles, high tracheal pressures, and coordinating breathing and speech needs, may experience higher TV (tidal volumes), Reducing potential speaking time and smaller than normal syllables per breath
Higher flow rates cause _________ peak inspiratory pressures
which ventilation require vigilant assessment and monitoring of ventilatory status (RR, ABG, Sp02, etc)
assisted control ventilation
Control Mode
In control mode, the ventilator delivers the preset tidal volume at a set time interval (time-triggered respiratory rate).
In Permissive Hypercapnia, what is the pressure limit for Plateau Pressure?
Low V/Q mismatch is related to?
Intrapulmonary Shunting
What relects the airway resistance (nonelastic resistance) and the elastic properties of the lung and chest wall (elastic resistance)?
Dynamic Compliance
Prophylactic Ventilatory Support
Early intervention of potential ventilatory failure by means of mechanical ventilation.
Minute computer that is designed to perform specific functions.
What is the normal Cl- Concentration?
103 mEq/L
Formula for CPP
Chest Tube size for large adults
36-40 French
What PCO2 level constitutes hypoventilation?
PC02 > 40
tracheostomy tube
(cannula) what the patient is attached to the ventilator by - the actual tube that is inserted
Consequence of raising inspiratory flow rate for lengths of inspiration and expiration
Shorten inspiration, lengthen expiration-->allows more time for exhalation
when do you change oral suction equipment and tubing?
every 24hr
Does it get harder or easier to initiate a breath as the Sensitivity number becomes more negative?
Which drug is given via aerosol before a bronchoscopy?
Brachial Plexopathy
Decreased movement or sensation in the arm and shoulder.
What is the best way to humidify?
Systemic humidification
Sine Wave
A graphic presentation of flow and time that has a horizontal "S" appearance.
What is the formula to calculate air flow resistance?
How do we defeat shunt on a vent?
Venous Return
Blood flow from the systemic venous circulation to the right heart.
List some drive mechanisms.
Pistons, bellows, reducing valves, microprocessor controlled pneumatics.
Do pressures in the alveoli, airways and pleura increase or decrease during inspiration when using negative pressure ventilation?
Pressures decrease
What does sustained hyperventilation of less than 24 hours cause?
Respiratory alkalosis, reduced cerebral blood flow and increased intracranial pressure.
Residual volume
Volume of air remaining in the lungs after a maximum exhalation
Assist control ventilation-->minute ventilation determined by pt. or preset?
Determined by pt.-->pt. is triggering rate, minute ventilation=tidal volume x rate (breaths/min)
alveolar hyperventilation is caused by (secondary to mechanical ventilation (5)
1. hypoxemia
2. pain
3. fear/anxiety
4. trying to compensate for metabolic acidosis
5. inappropriate preset ventilator (too fast)
What chest tube size is adequate for adults with Pneumothoraces?
16-20 French
Peak Inspiratory Pressure (PIP)
Maximum pressure measured during one respiratory cycle, usually at the end of inspiration.
Pulmonary Vascular Resistance
Resistance of the arterial system into which the right heart is pumping.
Barotrauma (volutrauma)
Air leak into the pleural space caused by excessive pressure or volume in the lung parenchyma.
Pressure Control Ventilation (PCV)
Once inspiration begins, a pressure plateau is created and maintained for a preset inspiratory time.
Define plateau pressure.
The pressure needed to maintain lung inflation in the absence of air flow.
Dual Control Mode
A combined mode between two control variables (i.e. pressure and volume) that are regulated by independent feedback loops so that the delivered breath switches between pressure control and volume control.
Three-Chamber Drainage System
A chest tube drainage setup that requires a vacuum source to provide continuous suction.
What happens to hepatic perfusion when blood volume or cardiac output is low.
It is decreased.
Expiratory reserve volume
Maximum volume of air that can be exhaled forcibly after a normal exhalation
Volume cycled ventilators-->how is airway pressure determined
Indirectly by patient's compliance and airway resistance
when the pt is ready for extubation, what might you expect to be done?
hyperoxygenation and suctioning
What is meant by volume-limited?
Termination of the inspiratory cycle when the preset volume is reached.
How do Mechanical Ventilators generate gas flow and volume?
Enter your back text here.
Automatic Tube Compensation
A mode of ventilation that offsets and compensates for the air-flow resistance imposed by the artificial airway.
How can we improve O2 level?
Increase FiO2, improve circulation, increase heart strength, transfusion, CPAP/PEEP, APRV
Define Hypoxia
When the O2 level in the body's organs and tissues is reduced.
Esophageal Obturator Airway (EOA)
Airway with a closed (blind) distal end and it is inserted into the esophagus. The cuff must be inflated to prevent air from getting into the stomach. It is not designed to be an artificial airway for positive pressure ventilation.
Define hypoxic hypoxia.
Lack of oxygen in the organs and tissues due to a reduction in inspired oxygen tension.
Bi-Level Positive Airway Pressure (BiPAP)
An airway pressure strategy that applies independent positive airway pressures (PAP) to both inspiration expiration.
What is considered normal airway resistance?
0.6 to 2.4 cm H20/L/Sec
Why are patients with ventilatory failure unable to ventilate themselves adequately?
Too weak, too stiff (decrease lung/chest wall compliance) or too obstructed
how is PETCO2 monitoring done?
1. by analyzing exhaled gas directly at the pt ventilator circuit

2. transporting a sample of gas via a small bore tubing to a bedside monitor
what is minute ventilation? norms
tidal volume x RR in 1 min

the tidal volume in pressure supported ventilation depends on what? (2)
1. pressure level
2. airway complaince
An alarm that results from the loss of 50 psi gas pressure is termed a/an:
Input Power Alarm.
Chest Tube (thoracostomy tube)
A tube that connects the pleural space and drainage system for removal of air or fluid.
Name some examples of impairments causing depressed respiratory drive.
Drug overdose, acute spinal cord injury, head trauma, neurologic dysfunction, sleep disorders, metabolic alkalosis, acute airflow obstruction, deadspace ventilation, acute lung injury, congenital heart disease, cardiovascular decompensation, shock, increa
What can cause Peak Inspiratory Pressure to be reached too soon?
Airway obstruction, Kinking of ET tube, Bronchospasm, low lung compliance, pressure limit set too low.
What does CVP reflect?
The status of blood volume in the systemic circulation, right ventricular preload.
What is Pulmonary Artery Pressure (PAP)?
Pressure measured in the pulmonary artery.
Consequence of expiratory time being too short in mechanical ventilation
Patient won't be able to exhale completely before next breath-->lungs become hyperinflated due to "breath-stacking"
how does PEEP affect FI02?
FI02 can be reduced when PEEP is sued
True/False: A cycle variable is a variable that ends Expiration.
False, it ends inspiration or I
Esophageal Gastric Tube Airway (EGTA)
A tube used in esophageal intubation. It has a patent distal end to relieve gastric distention. It has two ports and the ambu bag must be attached to the ventilation port.
Where should the low pressure alarm be set?
5 below the vent setting
What does Chamber Three in a three chamber chest tube drainage system do?
Regulates the amount of Suction
What are the 4 variables a ventilator can control during the inspiration of a breath?
Pressure, Volume, Flow and Time
A physician tells the nurse that a clients chest tube is to be removed. The nurse brings which of the following dressing materials to the bedside for the physician to use?
Petroleum gauze and sterile 4x4 gauze
What is a drive mechanism?
A system that causes air to be blown into a patient.
What is the coanda effect?
The tendency for air flow to hug a wall if directed towards that wall.
Weaning Tests Values:
MIF, NIP, Vt, Vital Capacity
- MIF: 20cm H2O or more
- NIP: more negative than -20cm H2O
- Vt: 5mL/kg or more
- Vital Capacity: 10-15mL/kg
what are the requirements for starting the trial for weaning? (2)
1. be at least 30 minutes of weaning
2. be no longer than 120 minutes of weaning
What happens to blood flow in hypertensive conditions during positive pressure ventilation due to the thoracic pump mechanism?
Enhances the outflow of blood from the right ventricle and into the left heart.
Where is a Chest Tube placed for pneumothorax?
At the second or third intercostal space anteriorly along the midclavicular line or midaxillary line.
if CPAP is 5cm of h20, what is the airway pressure during expiration and inspiration?
expiration: 5 cm (same as CPAP)
inspiration: 3 or 4cm (why? b/c 1-2cm of negative pressure was generated)
what is neg inspiratory force or pressure norm
amt of neg pressure that a pt is able to generate to initiate spontaneous RR

norm: -75-100 cm of h20
Why is exhalation often incomplete in extreme high compliance situations?
Due to a lack of elastic recoil in the lungs.
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