The following materials represent the Vortran TrainingProgram available on the Access CE website

www.accessce.com

Presented here as a courtesy for MCDH staff utilizing theVortran Automatic Resuscitator

Questions: David.Gibson@hcahealthcare.com

Gas Powered VORTRAN Automatic Resuscitator (VAR)for Short Term, Emergency Ventilation

by James I.C. Lee

Clinical Advisors

Gordon A. Wong, M.D., FACP, FCCP

Mario Romano, RCP

Barry Hickerson, EMT-P, CFP

Continuing Education

1.0 Contact Hours

CME through East Valley Medical Center, Glendora, CaliforniaCheck with your state licensing organizations about recognition of these providers for

your continuing education.

This module is supported by an Unrestricted Educational Grant.

Table of Contents

I. Objective

II. Introduction

III. Description of Available Devices

IV. Using an Automatic Resuscitator

V. Setting up Patient for Short Term Emergency Ventilation or Transport

VI. Clinical Applications of Automatic Resuscitator

VII. Reference

Objectives

At the completion of this in-service, the practitioners will be able to:

Use the equipment needed to provide short term, emergency ventilation for themechanically ventilated patients.

Describe the different resuscitation methods. Describe the rationale for using an automatic resuscitator. Complete exam components at 85% competency.

II. Introduction

In this section you will learn:

Oxygenation and ventilation Tidal volume Minute volume IE ratios Typical ventilation pressures Common terms

[A] Oxygenation and ventilation

Caring for mechanically ventilated patents is a logistically difficult and potentially

dangerous process. The importance of this method of ventilation has been shown when

comparing manual versus portable mechanical ventilation in a short term emergency

situation and during patient transportation.1-2 Using a transport ventilator, Hurst et al.3

found no appreciable changes in pH or PaCO2 compared to a marked respiratory

alkalosis when manual ventilation was used during patient transportation. Utilizing a

swine pediatric transport model, an automated transport ventilator provided more

effective ventilation than did bag-valve or demand–valve devices.4 Using the patient’s

ICU ventilator is often limited by lack of mobility in the size and weight of the ventilator

and the need for continuous power supplies.5 Similar and related limitations exist in

emergency medical care. Serious complications, such as pneumothorax, have been

reported during transportation with self-inflating bag-valve devices.6

In the emergency setting EMS providers commonly treat respiratory emergencies in

one of two ways, increase oxygen concentration of inspired gases and /or support

respirations. Any patient that has insufficient oxygenation or respiratory effort needs

immediate intervention. This may be in the form of providing more oxygen by using an

oxygen cannula or mask. It also may include an increase in tidal volume, respiratory rate

or complete ventilatory support in the case of a respiratory or cardiac arrest.

Do not confuse the need to provide supplemental oxygen to a patient that is in

need of ventilatory support. A patient with a low respiratory rate or decreased volume

needs ventilatory support in the form of a BVM or resuscitator. Patients with low oxygen

levels need oxygen therapy with an oxygen cannula or oxygen mask. Some patients

may require ventilation and oxygenation simultaneously.

[B] Tidal Volume and Minute Volume

When providing ventilatory support to a patient, it is important to understand some

basic numbers. The total volume of air in each breath is known as the tidal volume. This

is roughly 10 ml per kg. The average 70 kg patient would, therefore, have a tidal volume

of 10 ml x 70 kg = 700 ml. Multiply this volume times the respiratory rate, and you have

the minute volume. As in the 70 kg example, if the respiratory rate is 12 breaths per

minute, the minute volume is 700 ml x 12 = 8400 ml minute volume or 8.4 liters per

minute.

[C] IE ratios

During the inspiratory and expiratory phases of respirations, pressures change within the

lungs. At the beginning of the inspiratory cycle, pressures are at a minimum. Pressure is

required to inflate the lungs to the point were either a specific volume has been reached

or a specific pressure. When this volume or pressure has been reached, the expiratory

cycle starts. The inspiratory plus the expiratory time equals the complete respiratory

cycle. The inspiratory time and the expiratory time are typically not the same. The

relationship between the two is referred to as the inspiratory / expiratory ratio or IE ratio.

This ratio is typically 1:2 ~ 1:3. The longer expiratory time is due to the fact this is a

passive process.

In the case of a patient that is breathing 12 times per minute, the total respiratory

cycle is 5 seconds (60 seconds divided by 12 breaths). The inspiratory portion of this

may only be 1.0 to 1.5 seconds, with the remaining 3.5 to 4.0 seconds being the

expiratory phase. Pressure and flow rates control the “I” time while exhalation flow

resistance controls the “E” time.

During the respiratory cycle pressures are increased and decreased within the lungs. If

you think of the lung as two large rubber bags, as you inflate them, the pressure

continues to increase until it becomes difficult to inflate any further. The lungs are very

much the same. Factors that affect the amount of pressure it takes to inflate the lungs

are the presence of lung disease, obstructions, and external pressures, such as the

presence of a pneumothorax. Without disease or mechanical factors, lungs will become

fully inflated within the same pressure range regardless of size. This is an important

concept because the same pressure range will be appropriate for most patients

regardless of their size.

[D] Typical ventilation pressures

The typical pressures within the lungs start out at 2 cm-H2O and reach a peak of 25

– 30 cm-H2O. This peak pressure of 25 – 30 should provide adequate inflation in the

majority of patients. You may have to increase this for diseased lungs, patients with

asthma, or in cases of chest trauma. The peak pressure is known as “Peak Inspiratory

Pressure” or “PIP” and occurs at the end of the inspiratory cycle. This will be a setting on

pressure-cycled ventilators, such as the VAR™.

At the end of expiration, the body naturally retains a slight pressure in the lungs

known as “Positive End-Expiratory Pressure” or PEEP. This keeps the lungs from totally

collapsing at the end of the respiratory cycle and makes it easier for the next breath.

When using a ventilator, the operator will set an artificial PEEP to replace the natural

PEEP.

III. DESCRIPTION OF available DEVICES

In this section you will learn:

Methods of transport ventilation Effects of CPR Understanding gas-powered automatic resuscitators

[A] Manual Resuscitation

Since the late 1950's, the Bag-Valve-Mask (BVM) resuscitator, (see Figure 1),

originally developed by Ambu in Denmark, has been the mainstay of the healthcare

provider for emergency ventilation of the patient in respiratory and/or cardiac arrest.

Certainly, in the early days of CPR, these devices were the only available adjuncts for

the rescuer which did not require the use of exhaled breath to ventilate the patient. As

such, they were a significant advance in emergency respiratory care. However,

considering the major advances in medicine that have taken place over the last 35

years, we are still, in the most part, relying on old technology to perform the key task of

oxygenating the respiratory/cardiac arrest patient.

Figure 1 - Photo of Bag-Valve-Mask resuscitator

That technology has not only been superseded by superior equipment during this time

but has also been proven to be ineffective in the way in which it provides ventilation and

is potentially dangerous (especially in some non-protected airway situations). The

American Heart Association "Guidelines for CPR" published in the Journal of the

American Medical Association, October 28, 1992, 7 quite clearly noted that these devices

were generally ineffective in providing adequate ventilation to the patient.

A wealth of clinical evidence to support these claims has been accumulated over

the past 30 years and this evidence has, for the most part, been ignored as die-hard

"baggers" continue to utilize these devices. This continued use is not based on sound

clinical evidence that they provide good ventilation, but because - " it has always been

done this way." Some claim that the "feel" they get from the BVM allows them to make

clinical judgments on the patient's lung condition. In reality what they are probably

feeling is the back pressure created by the high flowrates generated when squeezing the

bag too hard or for too short an inspiratory time.

The majority of all prehospital ventilation is accomplished using the BVM device.

This device has improved with the addition of colorimetric CO2 monitoring and injection

ports. The BVM is an inexpensive, easy-to-use, dependable device for providing

ventilatory support for non-breathing patients or for supporting breathing patients. When

connected to an oxygen source and used in conjunction with a reservoir, the BVM can

obtain oxygen concentrations of greater than 90%. In the event of electrical failure

and/or loss of an oxygen source, the BVM allows continuation of ventilations on room

air. It is the mainstay of prehospital and emergency ventilatory support.

In the real world of emergency medicine, the BVM has some real limitations. First

of all, the BVM requires a dedicated set of trained hands. The operator must be exactly

synchronized with any and all patient movements. If the patient is receiving ventilations

via mask, it is almost impossible to maintain an adequate seal during patient

movements. If the patient is intubated, any deviation of the BVM operator may result in

an accidental extubation or right main stem intubation. During certain types of patient

movement, such as loading or unloading, the patient may not be ventilated at all! These

are all serious risks to the patient.

During ventilation of a patient by the BVM, it is impossible to accurately control

rate and volume. Even the best-trained hands cannot precisely control the rate and

volume delivered. The rate and volume directly affect the level of CO2 in the blood and

blood chemistry. If ventilations are too slow or are inadequate, an elevation in CO2

results. This in turn causes a drop in PH creating a respiratory acidosis. If ventilations

are too rapid or have too much volume, this lowers the PH and results in a respiratory

alkalosis. While hyperventilation and a decreased CO2 is thought to be beneficial to a

patient, primarily in head injuries and cardiac arrests, the effect is just the opposite. A

respiratory alkalosis will cause a left shift in the oxyhemoglobin disassociation curve and

impair the uptake and release of oxygen by the hemoglobin molecule. Moderate to

severe hyperventilation is dangerous to your patient, and it is, therefore, important to

control ventilations.

In an ill or injured patient, variations in the CO2 level and blood chemistry can

affect mortality and morbidity. It is vital that patients receiving ventilatory support have

their rate and controlled. With a manual device, this is not possible. The BVM is an

acceptable alternative for very short periods of time or when no other device is available.

It is inexpensive, easy to use and the set up time is immediate. In the prehospital care

setting, there is no time inside a crushed car or on a shopping mall floor to set-up a

ventilator that has 10 buttons, alarms, knobs and 10 feet of tubing. It is not practical and

will probably never happen. There are only a few practical ventilators for prehospital care

and attempts to simplify their use has nit been accomplished.

IV. Using an Automatic Resuscitator

In this section you will learn:

Use of the VAR Benefits of controlling rate and volume

[A] Automatic Resuscitator

In the 1960's, the first of the manually triggered, oxygen powered

resuscitators came onto the market and enabled healthcare providers to provide

100% oxygen under positive pressure to their patients. In the American Heart

Association "Guidelines for CPR" published in the Journal of the American Medical

Association 1986, 8 these flowrates were lowered to 40 liters per minute as a way of

reducing the inspiratory pressures, gastric distension, and risk of barotrauma. To

further reduce the risks to the patient, the maximum delivery pressure these devices

can produce was limited to 60 cm-H2O.

Cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC) are

important life-saving procedures.8 Adjunctive equipment for oxygenation, ventilation,

and airway control includes manually-operated self-inflating bag-valve units and

pressure cycled automatic mechanical ventilators and resuscitators. 8 During these

procedures, closed-chest compression may interrupt or interfere with pulmonary

ventilation. Intrathoracic pressures may vary depending upon the pulmonary

ventilation procedures and the use of adjunctive ventilatory equipment. The flow from

gas-powered resuscitators is pressure sensitive and may cease prematurely

because of high airway resistance "without alerting the rescuer." 7 Because of these

factors and the published guidelines, 7 the American Society for Testing and

Materials (Philadelphia, PA) has provided a "Standard Specification for Minimum

Performance and Safety Requirements for Resuscitators Intended for Use with

Humans" (ASTM Designation 920-93).9 Specifically, paragraph A3.1.31(11.1.1)

provides, "Manufacturer's Warning - These resuscitators are unacceptable for use

during closed chest cardiopulmonary resuscitation because the increase in

intrathoracic pressure caused during chest compression causes the resuscitator to

cycle from the inspiratory mode to the expiratory mode prior to adequate ventilation

of the lungs." 10

ASTM provides a prudent general warning for the typical pressure-cycled,

time-controlled mechanical ventilators, which could malfunction during chest

compression. A properly designed pressure-cycled, pressure-controlled automatic

mechanical ventilator should be able to adequate ventilation without the risk of

barotrauma during closed chest resuscitation. On the other hand, the manual bag

resuscitator requires trained synchronization during chest compression and may

reduce pulmonary ventilation and markedly increase intrapulmonary pressures

during inhalation.

[B] VORTRAN Automatic Resuscitator (VAR)

The VAR provides constant-flow, pressure-cycled ventilatory support (See

Figure 2), is a disposable gas-powered automatic resuscitator intended to provide

short term, emergency, non-continuous ventilatory support to patients while being

monitored by a clinician. During inhalation, exhalation will not start until peak

pressure is reached. During exhalation, inhalation will not begin until pressure drops

to the positive end-exhalation pressure (PEEP). This unique feature among

ventilators allows it to operate effectively during CPR.

Figure 2 - Photo of VORTRAN Automatic Resuscitator (VAR™)

The VAR runs on a continuous fixed flow rate of gas (inspiratory flow) of up to 40 L/min

(maximum flow at typical 50 PSIG supply pressure). When connected to a 50 PSIG high

flow source, the VAR will automatically deliver 40 L/min (667 mL/second). Peak pressure

may be adjusted from between 20 and 50 cm-H2O and PEEP is approximately 10% to

20% of the set peak inspiratory pressure (PIP). This device meets ASTM requirements

and includes an inspiratory pressure relief valve that opens automatically at

approximately 60 cm-H2O and has a distinctive and easily recognized sound. An optional

pressure gauge (manometer) allows visualization of airway pressure during use. Also,

the audible signal of the inhalation-exhalation breathing cycle allows the rescuer to

qualitatively monitor the breathing rate and associated inspiratory tidal volume as an

indication of high airway resistance or poor lung compliance.

The flow rate from your regulator will determine the “I” or inspiratory time.

Oxygen flows through the VAR and inflates the patient’s lungs. The rate at which this

happens is dependent on the oxygen flow rate and the size of your patient. Although a

flow rate of 15 lpm may work when you are trying to conserve oxygen, the I time will be

extended. Increasing the flow rate to 25 lpm will shorten the I time due to the increased

flow and decreased time needed to inflate the lungs.

The RATE control knob determines the rate at which gas escapes from the

breathing circuit by making an opening smaller or larger. This will determine the “E”

expiratory time. Changes in I or E times will affect the overall respiratory rate. Flow rate

determines I time; the RATE knob determines E time; together they control both the I

and E time. Turn the round RATE dial clockwise (inward) for a slower rate, or counter

clockwise (outward) for a faster rate.

Remove the VAR from the package and connect one end of the oxygen tubing to

the VAR DISS fitting and the other to your oxygen source. Turn on the oxygen source

and set the flow rate to 25 lpm (15 lpm if outside ambulance and you need to conserve

oxygen) or greater. Confirm you have gas flow through the resuscitator. Make sure all

connections are tight. Set PRESSURE setting to the 25-30 ranges. Connect flex tubing

from VAR to the endotracheal tube adapter (patient) and adjust PRESSURE control

knob for chest rise.

Verify chest rise, bilateral breath sounds and overall patient appearance. Confirm

with pulse oximeter readings and other vital signs. You should observe the inline

manometer rise and fall, indicating that the airway circuit is patent. Adjust the RATE

control knob to 12 ~ 20 breaths per minute or based on end tidal carbon dioxide levels of

35 ~ 40. Always follow your local hospital or EMS policies and procedures when you use

the VAR or any medical device.

Once you have the PRESSURE and RATE set, secure the VAR to the side of the

patient’s head so as to act as a strain relief for the ET tube. When moving the patient,

consider placing a portable oxygen cylinder on the stretcher to minimize the chance of

pulling the ET tube. During patient use, continue to monitor your patient observing chest

rise and fall, overall appearance and vital signs. Continue to make adjustments as

needed to correct PRESSURE or RATE. Never leave the patient unattended while on

the VAR.

A kinked or plugged ET tube will cause the VAR to flutter rapidly, as PIP is

reached very quickly. Identify the cause of this problem immediately and correct it. A

loose fitting or hose will cause a leak and PIP may never be reached. If a leak prevents

the VAR from reaching PIP, the VAR will never cycle. You must immediately identify the

problem and correct it. If you are unsure what is wrong, immediately substitute the VAR

with a BVM and attempt manual ventilation.

V. setting up Patient for Short Term Emergency Ventilation orTransport

In this section you will learn:

Method of transport ventilation Setting PIP and RATE FiO2 Settings – 100% or 50%

[A] Setting Short Term, Emergency, Non-Continuous Ventilator

The VAR provides short term, pressure cycled, and constant flow ventilatory

support for either breathing or non-breathing patients. This allows the patient to

receive consistent reliable ventilatory support. The VAR is pressure cycled on

inhalation and exhalation (PIP and PEEP), which minimizes the possibility of gas

trapping. During inhalation, exhalation will not start until PIP is reached. During

exhalation, inhalation will not begin until pressure drops to PEEP. For the

spontaneous breathing patient, the rate dial of the VAR is set so that the baseline

pressure is above the set PEEP, allowing the patient to initiate inhalation by drawing

the baseline pressure down to the set PEEP. Because the VAR is a constant flow

pressure cycled device, changes in patient compliance will result in changes in the

respiratory rate (stiffer or smaller compliance produces faster rates). The advantage

of this is that the danger of barotraumas is minimized. However, it should be

emphasized that the VAR is to be used only by trained personnel who continuously

monitor the patient. The VAR is not an ICU stand-alone ventilator with multiple

monitoring features.

[B] Setting up and use of the VAR is simple:

Set desired flow rate (Q) Adjust pressure dial to obtain desired PIP Adjust rate dial to obtain desired breathing rate

1. Set desired flow rate - The VAR runs on a continuous flow of gas (inspiratory

flow) of 15 to 40 L/min, depending on the patients’ inspiratory flow demand.

When connected to a 50 PSIG gas source, the VAR will automatically deliver 40

L/min (667 ml per second) per ASTM guidelines. Delivered tidal volume may be

determined by multiplying the flow in ml per second and the inspiratory time in

seconds, or using the tidal volume table (Table 1).

Table 1 - Tidal Volume Table at Various Flow Rates

Inspiratory Time (Seconds)Flow(LPM) 0.5 1.0 1.5 2.0 2.5 3.0

15 125 250 375 500 625 75020 167 333 500 667 833 100025 208 417 625 833 1042 125030 250 500 750 1000 1250 150035 292 583 875 1167 1458 175040 333 667 1000 1333 1367 2000

NOTE: The gas flow, patient’s lung compliance and PIP settings controlthe inspiratory time and tidal volume. Calculate inspiratory time (ti)by desired flow (Q) to attain tidal volume (TV = Q X ti).

2. Adjust pressure dial to obtain desired PIP. It may be adjusted from 10 and 50

cm H2O. PEEP is typically 10 to 20% of PIP (depending on the model of the

VAR). Inspiratory time and rate are adjustable over a wide range. Changes in the

pressure dial setting or flow will normally also affect the respiratory rate. It is

important to check all settings when making a change to any of the three

variables (flow, pressure, rate). For example: reducing the pressure dial setting

may cause the VAR to go into spontaneous breathing mode. If so, turn the rate

dial counter-clockwise to restart automatic cycling.

3. The rate dial controls exhalation time (time-e), and when dialed down enough

will cause the VAR to stop cycling automatically (infinite exhalation time). Under

these circumstances the VAR is delivering pressure supported ventilatory

support, and the patient must trigger the VAR to begin subsequent full

inhalations. If the patient is apneic or pressure control ventilation is desired,

restart automatic cycling of the VAR by adjusting the rate dial counter clockwise

until cycling begins again. Whenever the VAR stops cycling, the first step, in the

absence of obvious clinical factors, is to check if it is in pressure support mode by

rotating the rate dial counter clockwise (out). If rotating the rate dial counter

clockwise substantially (3 or 4 turns) does not start automatic cycling, the

patient’s airway may be occluded or there may be a very large leak.

Figure 3– Airway Pressure

4. The air entrainment valve is included with VAR which allows the patient to

entrain additional air and respond to the demands of the patient. Patient

entrainment of outside air is normally audibly detectable and the percent oxygen

delivered to the patient will be reduced. Specific concentrations of oxygen may

be delivered to the patient with the use of an oxygen blender.

5. Pressure pop-off valve - Although the design of the modulator is similar to that

of a pop-off valve and is inherently safe, the VAR is also equipped with a

redundant pop-off valve that relieves pressure at 60 cm H2O. When the pop-off

valve is activated, the pop-off valve piston will move slightly.

6. Manometer - Although peak pressures are listed on the side of the pressure dial,

those are only approximate. Clinicians using the VAR are still required to use

good clinical judgment and monitor the patient appropriately. A manometer may

be connected between the modulator and the patient connector tee.

Because the VAR is pressure cycled on PEEP as well as PIP, in the

pressure control mode there is no prolonged stage where the flow of exhalation

gas stops for a significant duration of time. In the pressure support mode,

exhalation time is determined by the patient. This occurs because the exhalation

time is set with the rate dial by varying the exhalation resistance so that the

patient just finishes exhalation with the beginning of the subsequent inhalation.

The volume of gas with which the patient’s lungs are inflated when reaching

PEEP is the same as with any other means of obtaining PEEP. As with all

ventilatory support modes, short exhalation times on patients with high airway

resistance may lead to gas trapping, which is not detectable in the patient’s

external airways. Upon occlusion of the patient’s airways, the VAR will stop

cycling and may sometimes cycle rapidly.

7. Using a Mask - The VAR will work with any mask that provides a good seal on

the patient (Figure 4). All clinicians should receive adequate training with a mask

prior to using the VAR. In the presence of a small leak, the VAR will still cycle

between PIP and PEEP. Noticeable changes in the presence of a leak are

increased inspiratory times and decreased expiratory times. The VAR works very

well with an endotracheal tube.

An inhalation may be immediately initiated by briefly removing the mask

from the patient or briefly disconnecting the modulator from the patient adapter

tee. In either event, inhalation begins because pressure drops down to PEEP

and the VAR is pressure cycled.

Figure 4- Photo of VAR with mask

8. Upon contamination of the VAR with vomitus, the VAR may be cleared by

disconnecting the modulator from the patient connector tee (see enclosed

instructions) and tapping out vomitus on a hard surface. Additionally, if needed,

the rate dial may also be removed to facilitate removal of vomitus from the

modulator. This operation should take less then 20 seconds, and in a lab setting

has consistently been shown to take approximately 11 seconds. Alternatively,

upon contamination with vomitus, the clinician may choose to discard the device

and use a new one. Inhalation and exhalation are audibly detectable and easily

recognizable during operation of the VAR.

9. Optional gas entrainment feature for VAR

If 100% of supply gas is to be delivered to the patient, connect the tubing to the greencolored gas connector marked "100%" with the DISS thread connection on the patienttee.

If 50% FiO2 delivery is desired, remove the green adapter and connect the oxygentubing to the gray colored entrainment adaptor marked "50%" with the Diss threadconnection on the patient tee.

The VAR will deliver FiO2 of 50% (10%) when connected to the gray colored 50%entrainment connector and is supplied with an oxygen flow from 6 to 15 L/min withresulting output flow of 20 to 40 L/min respectively (see "Entrained Flow Table 2").

10. The duration of an “E” cylinder when using a VAR will depend on the flow. An

“E” cylinder contains 625 L of gas. At 40 L/min, 625 L will last up to 15 minutes;

at 20 L/min, 625 L will last up to 30 minutes. 15 L/min orifice type flowmeters

used on many “E” cylinders will not be able to deliver more than 15 L/min. When

clinicians decide that 15 L/min is not sufficient flow, the VAR can be attached to a

regulator that has a high flow port (50 PSIG) to deliver 40 L/min. One of the

disadvantages of continuous flow of gas is that “E” cylinders will not last as long

as other ventilators. The length of use for various sizes of compressed oxygen

tanks (D, E, M & H) is a function of the supplied oxygen flow from 6 to 40 L/min

to VAR (see TABLE 3).

VI. Clinical Applications of Automatic Resuscitator

In this section you will learn:

Inter- and Intra Hospital of transport Use in MRI or CT Scan Using in Mass Casualty Incidents (MCI)

[A] Inter- and Intra Hospital transport

Ventilatory support is an important aspect of transporting a mechanically

ventilated patient out of the ICU. It is equally important under emergency care

conditions. Various techniques have been established for this purpose including the

use of manual self-inflating bag-valve ventilation, portable mechanical ventilation and

manual bag-valve ventilation during actual patient movement followed by returning to

standard mechanical ventilator at the destination. Significant expense and respiratory

therapy effort is required when portable and standard ventilators are used in

transporting ventilator dependent patients. Direct expenses include the purchase of

transport ventilators and the need for portable battery systems for standard

ventilators. Indirect costs include the set up and cleaning time for these ventilators.

The direct costs, indirect expenses and time requirements limit the number of

transport ventilators available in a given hospital.

The VAR with a portable continuous oxygen source is a useful, disposable,

pressure-cycled mechanical ventilator for transporting patients out of the ICU. The

automatic nature of the PEEP setting results in a small decrease (mean 1.4 cm-H2O)

in PEEP during transportation. The VAR is easy to use, extremely portable and is not

associated with any complications (e.g. no barotrauma). Similar results are

suggested for use of the VAR as an automatic resuscitator in emergency care

medicine. The VAR automatic, pressure-cycled, disposable mechanical ventilator

has been demonstrated to be well tolerated during transportation of mechanically

ventilator dependent patients outside of an ICU.

[B] Use in MRI or CT Scan

Many medical facilities do not have MRI compatible ventilators. As a result MRI

studies on intubated patients are frequently delayed until the patient is extubated.

Although there are mechanical ventilators that are MRI compatible, the cost for

purchasing them for MRI use only is impractical, especially in light of the limited

number of intubated patients needing an MRI. The VAR can be a safe and cost

effective ventilator for use in the MRI unit without the need to purchase capital

equipment. The VAR was tested and functioned properly in a Pickering 1.0 MRI unit

and General Electric 1.5 MRI unit. There was a slight image artifact, which according

to the MRI technician, was no more significant than what would be caused by a

spinal pin or dental fillings. By positioning the device away from the target, a

complete image was obtained. A Quality Control test was completed on the MRI unit

during the test procedure. QC was within normal limits. The device functioned

without incident. There was no attraction to the magnet or any movement of the

VAR. The patient was able to trigger the device during spontaneous breathing

without incident.

Figure 5 - VAR with Extension Tubing

[C] Use during Mass Casualty Incidents (MCI)

The March 1995 Tokyo, Japan incident sounded a wake-up call to health care

workers. The intentional release in the subway system, Sarin a chemical neurotoxin,

resulted in 11 deaths and five thousand casualties exhibiting a variety of toxic symptoms

requiring medical evaluation. This number rapidly overwhelmed the health care system.

(Brackett D.W., Holy Terror, Armageddon in Tokyo, New York: Weatherhill, Inc. 1996). It

had long been recognized that it was not a matter of “if” but “when” a terrorist initiated

mass casualty incident would happen. Recognizing this potential scenario for the

National Capital Region, the Ottawa Hospital embarked on a series of planning and

preparation exercises.

The Respiratory Therapist representative on the Chemical, Biological, Radiation,

Nuclear Committee noted that it became rapidly apparent that there was a serious

discrepancy between the number of ventilators that would be required and the actual

ventilator resources that would be available. Although most large hospitals have

ventilators available at each site, these numbers would be woefully inadequate in the

context of a mass casualty incident. An additional complicating factor was that, on

average, 60% of the ventilators are in use with the remaining 40% either in for

maintenance or in readiness for the next patients.

In any mass casualty incident (accidental, industrial or terrorism), the finite limit of

ventilators determines the number of patients that can be managed. This limit was

determined to be both unacceptable and avoidable. The Respiratory Therapy

department wanted to prevent compromised patient care and was cognizant of the two

major factors facing the health care institution - that of limited health care dollars/funding

and the potential number of patients that would present in a mass casualty incident. So,

the department undertook a study to determine the most cost effective way of providing

basic mechanical ventilation to a large number of patients.

The VAR offered the capabilities of managing the largest number of patients at the

most financially responsible cost. In addition, the unit had the advantage of ease of use.

The other very important variable was that the equipment offered a simple solution to the

handling of contaminated units from a biological or terrorism incident because it was

disposable. The cost of the other units prohibited one time use and would result,

therefore, in a lengthy and expensive decontamination process, which might also pose a

hazard to hospital staff charged with decontaminating the units.

VII. References.

1. Gervais HW, Eberle B, Konietzke D, Hennes HJ, Dick W. Comparison of bloodgases of ventilated patients during transport. Crit Care Med 1987;15:761-763.

2. Braman SS, Dunn SM, Amico CA, Millman RP. Complications of intrahospitaltransport in critically ill patients. Ann Intern Med 1987;107:469-73.

3. Hurst JM, Davis K, Jr., Branson RD, Johannigman JA. Comparison of bloodgases during transport using two methods of ventilatory support. J Trauma1989;29:1637-1640.

4. Auble TE, Menegazzi JJ, Nicklas KA. Comparison of automated and manualventilation in a prehospital pediatric model. Prehosp Emerg Care 1998;2:108-111.

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