Mechanical Ventilator Final

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Summer Semester 2011

The power source used by the ventilator provides the energy to perform the work of ventilating the patient. Ventilator power sources include what?

1) electrical
2) pneumatic
3) dual electrical-pneumatic

Early ventilators such as the tank ventilator and chest cuirass were designed to operate as what?

Negative pressure ventilators

There are two types pf pneumatically powered ventilators: pneumatic and fluidic. True or false?

True

Most of the current ICU ventilators use gas power to provide the driving force or flow to the patient, and they use an electrically powered micro-processor to control special valves that regulate the delivery of gas for inspiration and expiration. True or false?

True

Closed-loop ventilator logic systems are called "unintelligent" because they cannot be programmed to respond to changing conditions. True or false?

False

A drive mechanism for positive pressure ventilators includes all of the following EXCEPT what?

A) rotary drive piston
B) spring-loaded bellows
C) flow-controlling solenoid
*D) chest cuirass vacuum

The major advantage of negative pressure ventilators is what?

an endotracheal tube is not required

If the internal circuit of a ventilator allows the gas to go directly from its power source into the patient, is called a what?

single-circuit ventilator

A ventilator for which the primary power source generates a gas flow that compresses another mechanism, such as a bag or bellows, and the gas contained in the bag or bellows goes to the patient is termed a what?

double-circuit ventilator

The exhalation valve in most ICU ventilators is mounted inside the ventilator, where it is not visible, An internally mounted exhalation valve is usually controlled by a mechanical device such as a solenoid valve. True or false?

True

Ventilator compressors are capable of reducing or increasing internal volumes, resulting in a change in pressure. These compressors can use any of the following mechanisms EXCEPT what?

A) piston-driving mechanisms
B) rotating blades (vanes)
C) moving diaphragms or bellows
**D) All of the above mechanisms can be used

Some ventilators have built-in air compressors. These built-in compressors can be used to power the ventilator when there's a what?

a 50-psi air wall outlet is not available

Modern ICU ventilators use flow control valves. These valves control or direct gas flow by opening and closing either completely or in small increments. True or false?

True

Flow control valves have a rapid response time and great flexibility of flow control. Flow control valves include all of the following EXCEPT what?

**A) piezoelectric valves
B) proportional solenoid valves
C) stepper motors with valves
D) digital valves with on-off configurations

The clinician who operates a ventilator sets certain knobs or controls using a control panel to establish the pressure and the pattern of gas flow directed from the device to the patient. This statement describes a what?

User interface

How many phase variables are there in a mechanical ventilator cycle?

Four

What variable begins the inspiratory phase of a ventilator breath?

Trigger variable

The variable that ends the inspiratory phase is called the what?

Cycle variable

The two most common cycle variables for adult ventilators in CMV mode are what?

I. time
II. flow
III. volume
IV. pressure
A) I and III
B) II and IV
**C) III and IV
D) I and II

Decreased lung compliance during time-cycled PCV will cause what?

Decreased volume delivery

Decreased lung compliance during volume-cycled, volume-controlled ventilation will cause what?

Increased airway pressure

A ventilator variable that cannot be exceeded during inspiration is know as the what?

Limit variable

The ventilator mode that is either patient triggered or time triggered and allows the patient to breathe spontaneously between mandatory breaths is known as what?

SIMV

Patients suffering from sleep apnea are most commonly treated with what?

CPAP

The amount of volume delivered to the lungs with pressure control node is primarily dependent on what?

I. the inspiratory time
II. the compliance of the lungs
III. the airway resistance
IV. the pulmonary blood volume
A) II only
B) I and III only
**C) I, II, and III only
D) I, III, and IV only

Pursed lip breathing can be mimicked for an intubated patient by using what?

Expiratory retard

An I:E ratio that will provide the greatest amount of time for exhalation is what?

1:4

The inspiratory pause is occasionally used to help increase the peripheral distribution of gas and improve oxygenation. True or false?

True

Expiratory retard would be most beneficial for a patient who suffers for what?

Emphysema

PEEP is the application of pressures above ambient to improve oxygenation in the spontaneously breathing patient. True or false?

False

A ventilator that develops a constant (square wave) flow pattern that is not influenced by changes in compliance or resistance is a what?

Constant flow generator

Which of the following variables causes the ventilator to begin expiration?

A) trigger variable
B) limit variable
**C) cycle variable
D) generator variable

Which of the following variables cause the ventilator to start inspiration?

**A) trigger variable
B) limit variable
C) cycle variable
D) generator variable

If the ventilator is set at a frequency of 15 bpm and the inspiratory time is set at 1.5 seconds, what is the expiratory time and the I:E ratio?

TCT=60/15=4 sec
I Time: 1.5 sec
E time: 4-1.5=2.5 sec
I:E=2.5/1.5=1:1.7
**B) 2.5 sec, 1:1.67

Which of the following variables sustains inspiration?

A) trigger variable
B) cycle variable
**C) limit variable

Indication for mechanical ventilation include all of the following EXCEPT what?

A) apnea
B) acute ventilatory failure
C) severe oxygenation deficit
**D) metabolic acidosis

Hazards of mechanical ventilation include all of the following EXCEPT what?

A) O2 toxicity
B) volutrauma and barotrauma
**C) permissive hypercapnea
D) compromised cardiac output and right heart venous return

Reducing the work of breathing, for a short period of time, may be a secondary indication for mechanical ventilation. True or false?

True

Generally, ventilatory insufficiency accompanied by hypocarbia and tachypnea should NOT be an indication for mechanical ventilation. True or false?

False

A patient is seen in the emergency room. She exhibits paralysis of the lower extremities that is getting progressively worse. Vital capacity is 12 ml/kg. MIP is -24 cmH2O. SpO2 is 92%. Blood gases are not yet available. The clinician suspects Guillian-Barre syndrome. Which of the following types of therapy do you think this patient is most likely going to require?

A) Narcan (a narcotic-blocking agent)
B) Oxygen therapy by non-rebreathing mask
**C) Intubation and ventilatory support
D) Incentive spirometry to improve muscle strength

Which of the following are conditions affecting the CNS that are associated with reduced drive to breathe?

A) General anesthesia
B) stroke
C) narcotics
**D) all of the above

A forced vital capacity (FVC) of less than what indicates the patient may need ventilatory support?

15 ml/kg

A patient in the emergency room arrives from the scene of a motor vehicle accident. He is unconscious and non-responsive. ABG's on a non-rebreather mask show a PaO2 of 45 mmHg, PaCO2 of 93 mmHg, and pH of 7.09. Which of the following would you recommend?

A) Recheck vital signs
**B) intubate and ventilate
C) change to a venti mask and coach the patient to breathe
D) Administer bicarbonate

A patient with a history of COPD and CO2 retention is admitted to the ER. He was brought in by ambulance. He is currently on a partial rebreathing mask. He appears to be sleeping but rouses when talked to. He remains lethargic. HR is 11 beats/min. BP is 128/78. RR is 5 bpm. BS reveal bilateral crackles and wheezes, but BS are difficult to hear. Which of the following would you recommend immediately?

A) Recheck vital signs
B) intubate and ventilate
**C) Change to a venti mask and coach the patient to breathe
D) Administer an aerosol treatment with a bronchodilator and compressed air

Which of the following is the most sensitive test or procedure to predict the need for mechanical ventilatory support for a patient with acute neuromuscular disease?

A) Peak flow rate
B) ABG's
C) CXR
**D) Maximum inspiratory force

Which of the following parameters would provide indications that a patient with myasthenia gravis is developing weaker than normal ventilatory strength?

A) Functional residual capacity is decreased
**B) Inspiratory force is -22 cmH2O
C) PaCO2 is 105 mmHg
D) PaCO2 is 38 mmHg

Before beginning ventilatory support for a patient with chronic bronchitis, thew blood gas results in the ER are a PaCO2 of 78 mmHg and a pH of 7.31. After 1 hour of mechanical ventilation, the patient has a PaCO2 of 45 mmHg and a pH of 7.54. Which of the following statements is true?

**A) The patient is being hyperventilated beyond her normal PaCO2 level
B) The patient is in oxygen-induced hypoventilation
C) The RT needs to increase the minute ventilation
D) No ventilator changes should be made at this time

You are asked to evaluate a patient with COPD for possible intubation and mechanical ventilation due to insufficient alveolar ventilation. Which of the following parameters will provide an appropriate index of insufficient alveolar ventilation?

I. MIP
II. Shunt fraction
III. PaCO2
IV. VH
V. pH
**A) I, III, and IV
B) III and V
C) III, IV, and V
D) II and III

An adult patient is receiving oxygen by nasal cannula at 6 L/min. ABG results indicate the following: pH=7.29, PaCO2=79 mmHg, HCO3=39 mEq/L, BE=11, PaO2=87 mmHg, and SaO2=95%. The most appropriate recommendation would be to what?

A) intubate and mechanically ventilate
B) administer bicarbonate
C) administer isoproterenol by aerosol
**D) decrease the FIO2 and monitor the patient's ventilation

A 28 year old female is believed to have taken an overdose of barbituates. Her RR is 6-8 bpm. Appropriate care at this time would be to what?

A) closed chest compressions
**B) endotracheal intubation and mechanical ventilation
C) bicarbonate administration
D) aminophylline administration

Which of the following would you use for a trauma victim with crushed chest injuries?

A) A negative-pressure ventilator
B) pressure-cycled ventilator
**C) volume-cycled ventilator
D) a manual resuscitation bag

A patient is receiving VC-CMV. His PaO2 is only 51 mmHg on a FIO2 of 1.0 and 15 cmH2O of Peep. His current alveolar pressure is 45 cmH2O. What would you now suggest to improve his oxygenation without causing lung damage?

**A) switch to PC-CMV with 25 cmH2O set pressure, using 15 peep and FIO2 of 1.0. Allow the patient's PaCO2 to increase if necessary
B) Continue volume ventilation but lower the VT to reduce alveolar pressures
C) Switch to BIPAP, using 15 as Plow and 25 as Phigh
D) Maintain current settings

The ventilator mode that is either patient triggered or time triggered and allows the patient to breathe spontaneously between mandatory vent breaths is known as what?

Synchronized intermittent mandatory ventilation (SIMV)

Patients suffering from sleep apnea are most commonly treated with what?

CPAP

The mode of ventilation used for non-invasive positive-pressure ventilation is what?

BIPAP

A patient is being ventilated with VC-CMV mode. If the ventilator rate is decreased, which of the following should be anticipated in the absence of patient triggering?

I. increase in patient's PaCO2
II. unchanged minute ventilation
III. decrease in alveolar ventilation
IV. increase in delivered tidal volume
A) III only
B) I and II
**C) I and III
D) II and III

During VC-CMV, which of the following will increase peak pressure?

!. increased airway resistance
II. decreased airway resistance
III. increased lung compliance
IV. decreased lung compliance
V. increased inspiratory flow rate
VI. decreased inspiratory flow rate
A) I and III
B) I and IV
C) I, II, and IV
**D) I, IV, and V

A 75 kg IBW male patient on mechanical ventilation has the following ABG's and ventilator settings: pH=7.46, VT=1000 ml, PaCO2=33 mmHg, VC-SIMV=6 bpm, RR=13 bpm, PaO2=66 mmHg, FIO2=0.60, HCO3=25 mEq/L, peep=0. Appropriate therapy would be to what?

A) decrease SIMV rate
B) increase FIO2 to 1.00
C) implement peep
**D) decrease VT

A clinician has set a ventilator so that the inspiratory time is 33% of the total cycle time. This would result in an I:E ratio of what?

RR-10 bpm
TCT=60/10=6 sec
IT=6x0.33=2 sec
ET=6-2=4 sec
I:E=2/4=2=1:2

A patient who is triggering each inspiration for a ventilator in the VC-CMV mode will be able to establish his or her own what?

A) frequency
B) VT
C) VE
**D) A and C only

A patient being maintained in the PC-SIMV mode will what?

receive a mechanical breath at present time intervals

PSV, when appropriately set, results in all of the following advantages EXCEPT what?

A) the inspiratory phase end when a present minimal flow is reached
**B) the resulting VT remains constant
C) each breath is patient triggered
D) the peak flow is determined according to patient inspiratory demand

PSV should be avoided in patients with ventilatory muscle fatigue and when a patient has a high WOB. True or false?

True

PSV modes of ventilation include all of the following EXCEPT what?

A) VC-SIMV
**B) VC-CMV
C) PSV
D) MMV

Dual-control pressure ventilation, with a breath-by-breath volume target, is currently available on the majority of newer-generation ventilators. This mode comes in 2 forms: pressure-regulated volume control and volume support. Both are entirely spontaneous modes. True or false?

False

A patient has a strong respiratory drive and is intubated to protect his airway. What would be an appropriate mode for this patient?

PSV with an inspiratory pressure of 15 cmH2O

What is the calculation for determining minute ventilation in L/min?

VE= VT x f

What are the calculations for BSA according to Dubois for females and males?

Males: 4 x BSA
Females: 3.5 x BSA

According to White what is the calculation for VT (tidal volume) on the Servo 900C?

VT = VE x RR
IBW in kg x ml (multiply by 1000 to convert ml to L)

If you were placing an asthmatic on mechanical ventilation according to Pilbeam & the NBRC what VT ranges would you choose & are there any other considerations ?

VT range = 5-8 ml/kg
other considerations would be longer I:E ratios and lower rates

Lower flow rates will increase/decrease the I time?

increase

High flow rates will effect a mechanical breath in 3 ways which are what?

1) increased PIP
2) decreased I time
3) decreased oxygenation

The 2 constant flow patterns are what?

rectangular and square

If your patient was on a rate of 20 bpm with a set IT% of 20 and a pause time % of 5, what would your I time and I:E ratio be?

TCT= 60/20=3 sec
IT= 3x(20+5)=3x25%=0.75 sec
ET=3-0.75=2.25 sec
I:E=2.25/0.75=1:3

Which of the following ventilators is controlled by fluidic logic systems?

A) Siemens 300
**B) Sechrist IV-100B
C) Bird 8400ST
D) Bear 1000

According to the equation of motion of the respiratory system, a ventilator can control all of the following variables EXCEPT what?

A) volume
**B) resistance
C) pressure
D) flow

If the pressure waveform of a ventilator remains the same when a patient's lung mechanics change, then what is the ventilator?

...

Calculation for RR is what?

RR = VE (in ml) x VT

Which of the following are characteristics of a ventilator that functions as a true volume controller?

I. its pressure waveform changes with changes in lung mechanics
II. it measures and uses volume to control the volume waveform
III. its volume waveform stays constant with changes in lung mechanics
A) I and II
B) I and III
C) II and III
**D) I, II, and III

When you adjust the pressure drop necessary to trigger a breath on a vent, what are you adjusting on the machine?

positive end-expiratory pressure (peep) level

All vents offer a mode that intermixes spontaneous breaths with vent breaths, this is called what?

SIMV mode

All adult vents offer a way to augment spontaneous breaths with a boost, this is called what?

pressure support

All adult vents offer the choice of ? controlled vent breaths and ? controlled vent breaths for any mode that offers a machine breath.

volume
pressure

The activity of which muscle is an indicator of adequate PSV levels?

sternocleidomastoid muscle

A patient receiving 50% O2 from a venti mask has a PaCO2 of 45 mmHg. The patient is to be switched to a mechanical vent. What FIO2 would you set to achieve a PaO2 of 60 mmHg?

Desired FIO2 = PaO2 (desired) x FIO2 (current)/PaO2 (ABG)
= 60 x 0.50/45= 30/45= 0.67

The goal in selecting a specific fraction of inspired O2 (FIO2) is to try to achieve clinically acceptable arterial oxygen tensions between what?

60 and 100 mmHg

To provide a way of restoring normal oxygenation and replacing tissue oxygen storage when oxygen debt and lactic acid accumulation have occurred, many practitioners start with an FIO2 of what?

1.0 or 100%

Continuous use of 100% O2 is not recommended, since it can quickly result in absorption atelectasis and, in long term, cause O2 toxicity airflow obstruction and air trapping in patients who have trouble triggering a breath during mechanical vent. True or false?

True

An FIO2 > 60-65% increases the risk of O2 toxicity and intrapulmonary shunting. True or false?

True

During initial vent setup, the sensitivity is commonly set between what and what?

-1 and -2 cmH2O

Flow triggering is now the preferred method of triggering, since it has a slightly faster response time compared to pressure triggering. True or false?

True

Vent heated humidification devices include all of the following EXCEPT what?

A) passover humidifier
**B) ultrasonic humidifier
C) wick humidifier
D) active heat and moisture exchanger

Systems to manage condensate in the vent circuit include all of the following devices EXCEPT what?

A) water traps
B) water traps with spring-loaded valves
C) heated wire circuits
**D) smooth bore inspiratory limbs

Heat moisture exchangers (HME) are contraindicated in all of the following EXCEPT with what?

A) in patients with thick, copious, or bloody secretions
B) when exhaled VT is < 70% of inhaled VT (means you have a leak)
**C) in patients with tracheostomies
D) in patients with body temps of < 32 degrees Celcius (hypothermia)

Large VT delivery may compromise the ability of the HME to humidify inspired gases. True or false?

True

Low pressure alarms, used to detect patient disconnections and leaks in the system, are usually set at about what?

10 cm H2O below PIP

Apnea alarms are used to monitor mandatory and/or spontaneous breaths. An apnea period of no more than 30 seconds is the most accepted maximum. True or false?

False

A vent may malfunction during use. When this occurs, the clinician must FIRST do what?

Ensure that the patient is being ventilated

Goals of mechanical vent management include all of the following EXCEPT what?

**A) stabilizing metabolic acidosis
B) maximizing patient-vent synchrony
C) reducing WOB
D) reducing patient anxiety

To minimize dynamic hyperinflation (auto-peep) by setting the lowest possible VE that produces acceptable gas exchange, a goal in COPD is to provide the longest expiratory time (TE) possible. This includes all of the following EXCEPT what?

A) decreasing TI
**B) increasing FIO2
C) reducing f and/or VT
D) accepting hypercapnia (PaCO2 higher than the patient's normal value)

Severe asthma requiring mechanical vent may be complicated by barotrauma secondary to all of the following EXCEPT what?

A) pneumothorax
B) pneumomediastinum
C) subcutaneous emphysema
**D) hepatomegaly

What goals does the RT hope to achieve when selecting initial vent support settings?

I. optimize oxygenation
II. optimize ventilation
III. maintain acid-base balance
IV. avoid harmful side effects
A) I only
B) II and III only
C) I, III, and IV
**D) I, II, III, and IV

Which of the following modes of vent support would you initially recommend for a patient whose compliance or resistance is likely to change rapidly?

A) pressure-targeted continuous mandatory vent (CMV)
B) pressure-supported vent (PSV)
**C) volume-targeted CMV
D) pressure-targeted intermittent mandatory vent

Compared to a pressure-controlled strategy, what is the primary advantage of volume-controlled vent support?

Guarantees a minimum minute ventilation

What is the recommended range for the tidal volume for the initial vent settings in the volume control mode?

8-10 ml/kg (or 8-12 ml/kg)

If the patient is being ventilated via a synchronized intermittent mandatory vent with patient vent support, what would probably happen to PaCO2 if the patient suddenly had no spontaneous breathing?

the PaCO2 would increase

Which of the following represents a clinical situation where patial vent support is commonly used?

A) patient with head trauma
**B) during weaning from continuous mandatory vent
C) while ventilating an asthmatic
D) in a drug overdose

When a patient is initially started on mechanical vent common orders from the physician in the patient's chart include all of the following EXCEPT what?

A) FIO2
B) mode
**C) sensitivity
D) tidal volume

A physician orders intubation and mechanical vent in the synchronized intermittent mandatory vent mode for a 170-pound adult man with neuromuscular disease. Which of the following initial settings would you recommend?

Rate/VT
**A) 8/min/900 ml
B) 15/min/1100 ml
C) 14/min/700 ml
D) 16/min/1000 ml

Name three types of power sources used by vents to provide the energy to perform the work of ventilating the patient.

1) electrical power
2) pneumatic (gas) power
3) combo of the two

Name the early vent type known as the tank vent or chest curass.

iron lung (NPV)

What is another name for the control panel of the vent?

user interface

Define a closed loop system.

-"intelligent" system
-compare the set control variable to the measured control variable
-an example is the mode of ventilation called mandatory minute ventilation
-works with your patient

What are two commonly used control variables?

pressure & volume

Name 3 clinical benefits of noninvasive positive pressure ventilation (NPPV)?

1) prolongs survival
2) preserves airway defenses
3) reduces need for intubation

Name 3 indications for NPPV.

1) respiratory rate > 25 bpm
2) moderate to severe acidosis (pH 7.30-7.55, PaCO2 45-60 mmHg)
3) moderate to severe dyspnea with use of accessory muscles and paradoxical breathing pattern

Name 3 exclusion criteria for NPPV.

1) apnea (respiratory arrest)
2) high risk of aspiration (excessive secretions)
3) facial burns

Name the 4 factors that may vary FIO2 in NPPV.

1) O2 flow rate
2) type of leak port in the system
3) site where O2 is bled into the circuit
4) IPAP and EPAP

Discuss the steps for initiating NPPV

1) place patient in upright position or sitting up. Carefully explain procedure, including goals and possible complications
2) using a sizing gauge, make sure a mask is chosen that fits properly
3) attach interface and circuit to vent, turn on vent and adjust it initially to low pressure settings
4) hold or allow the patient to hold the mask gently to the face until patient becomes comfortable with it. encourage patient
5) monitor O2 saturation, adjust fractional inspired O2 (FIO2) to maintain O2 saturation above 90%
6)secure mask to patient. dont make straps too tight.
7) titrate inspiratory and end-expiratory positive airway (IPAP and EPAP) to achieve patient comfort, adequate exhaled tidal volume, and synchrony with the vent. dont allow peak pressures to exceed 20 cmH2O
8) check for leaks and adjust strap is necessary
9)monitor RR, HR, level of dyspnea, O2 sats, VE, and exhaled VT
10) obtain ABG within one hour

List the 3 synonyms for volume ventilation

1) volume targeted
2) volume limited
3) volume controlled

List the 3 synonyms for pressure ventilation

1) pressure targeted
2) pressure limited
3) pressure controlled

The primary variable used by the vent to caused inspiration is called what?

control variable

How many phase variables are there in a mechanical vent cycle?

four

List the 4 phases of a breath

1) change from exhalation to inspiration
2) inspiration
3) change from inspiration to expiration
4) exhalation

A breath that is triggered, limited, and cycled by the mechanical vent is which of the following?

A) assisted breath
**B) mandatory breath
C) spontaneous breath
D) synchronized breath

A breath that is triggered, controlled, and ended by a patient is which of the following?

A) assisted breath
B) controlled breath
**C) spontaneous breath
D) synchronized breath

A breath that is patient triggered, vent controlled, and vent cycled is which of the following?

**A) assisted breath
B) controlled breath
C) spontaneous breath
D) pressure-supported breath

During pressure-controlled ventilation, the patient's airway resistance increases; this causes which of the following to occur?

A) Peak pressure increases
B) peak pressure decreases
C) tidal volume increases
**D) tidal volume decreases

During volume-controlled ventilation, the patient's lung compliance improves; this causes which of the following to occur?

A) peak pressure increases
**B) peak pressure decreases
C) tidal volume increases
D) tidal volume decreases

Name the 5 clinical objectives of mechanical ventilation

1) reverse acute respiratory failure
2) reverse respiratory distress
3) reverse hypoxemia
4) prevent or revers atelectasis and maintain FRC
5) reverse respiratory muscle fatigue

What pulmonary diseases cause airway resistance and result in increased WOB?

Cystic fibrosis
Bronchitis
Asthma
Bronchiectasis
Emphysema

A 48 year old woman with a past medical hx of CHF and HTN is brought to the ED with acute onset of dyspnea. The patient has pink frothy sputum; her pulse is 120, irregular, RR 26 and labored. BS reveal bilateral crackles with rhonchi. ABG results on a NRB are as follows: pH= 7.31, paco2= 50 mmHg, sao2= 72%. What would you recommend and why?

Intubate because the ABG values reveal impending or acute ventilatory failure, which is the hallmark clinical manifestation for mechanical vent

A 79 year old male with inoperable lung cancer, develops acute severe dyspnea. HR 104 but regular, RR 24 with accessory muscle usage, BS decreased bilaterally in bases. How would you treat him?

O2 therapy would best fit, then get a CXR and an ABG

SIMV, positive airway pressure, mandatory breaths during mechanical ventilation can normally be cycled into expiration by which 2 control variables?

I. time
II. flow
III. volume
IV. pressure
**A) I and II
B) I and III
C) II and III
D) II and IV

A mode of ventilation that provides a constant positive pressure during inspiration to a spontaneously breathing patient and also helps reduce the WOB through the ETT and vent circuit is termed?

Pressure support ventilation (PSV)

According to the equation of motion of the respiratory system, a vent can control all of the following variables EXCEPT what?

A) volume
**B) resistance
C) pressure
D) flow

If the pressure waveform of a vent remains the same when the patient's lung mechanics change then what is the vent?

Pressure controller

If a vent, not the patient, initiates a breath, what is the trigger variable?

time trigger

A vent that controls flow and delivers a rectangular flow waveform will also exhibit what wave form?

descending ramp pressure

Full vent support (FVS) is provided when?

vent rates are high (8 bpm) or more and VT is adequate for the patient ( 6-12 ml/kg) of IBW

Partial vent support (PVS) is provided when?

set machine rates are lower than 6 bpm and the patient participates in WOB to help maintain effective alveolar ventilation

When is PSV used and name 2 modes of PSV

PSV is used to overcome WOB for spontaneous breathing patients; to decrease WOB further in COPD or SIMV by setting pressure lvel higher than normal; to provide full vent support in the assist mode, in which each patient breath is a PS breath
modes: CPAP, SIMV, VS, PAV, MMV

Name the types of breath delivery and define each

-Mandatory: AC/CMV modes; vent controls the timing or VT (or both) ( volume targeted, volume cycled, patient triggered breath)
-Spontaneous: SIMV/PSV/VS; patient controls timing and VT ( not on a set value) ( patient controls pressure and volume)
-Assisted: all or part of breaths are generated by vent; if airway pressure increases above baseline, during inspiration, the breath is assisted

There are 3 breath delivery techniques, name them

CMV
SIMV
Spontaneous modes

Define continuous mandatory ventilation (CMV)

all breaths are mandatory and can be volume or pressure targeted. breaths also can be patient triggered or time triggered. when patient triggered, it's also assist/control (AC). when time triggered, mode is called controlled vent or control mode.

Name the triggers of assist control (AC) ventilation

Time trigger
Patient trigger

Name the 2 problems of CMV ventilation

-vents sensitivity setting. if it's overly sensitive to patient effort, the vent triggers rapidly (auto triggers) without delivering the set volume or pressure
-response time, which is the time increment between when a patient effort is detected and when flow from the vent to the patient begins
-preventing respiratory alkalosis is difficult in some patients in this mode

Define volume targeted CMV

(also called volume controlled CMV [VC-CMV]) most common mode in CMV. allows patient to do 33-50% or more of work of inspiration. this is especially true when inspiration is active and the set gas flow doesn't match the patient's inspiratory flow demand.

Define pressure targeted CMV

(also called pressure controlled CMV [PC-CMV]) (PCV) all breaths are time or patient triggered, pressure targeted (limited) and time cycled. the vent provides a constant pressure to the patient during inspiration.

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