X-Message-Number: 2555
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Subject: CRYONICS.SCI Alcor Builds New MALSS
Date: Fri, 14 Jan 94 11:22:28 PST
ALCOR BUILDS NEW MALSS
The Alcor Foundation has constructed a new and considerably improved
Mobile Advanced Life Support System (MALSS). Since 1987, Alcor has used
the MALSS built and owned by Cryovita Laboratories. Planning for a new
unit had been in progress for over a year and many of the parts had been
acquired; however, construction did not begin in earnest until late 1993
(when Cryovita informed us that it would be ending our agreement for the
use of theirs).
The purposes and definition of a MALSS were described in the March,
1987 issue of *Cryonics* as:
"...an easily transportable, fully self-contained extracorporeal
perfusion and cooling unit for use in the transport of biostasis
patients. The objectives to be met in the design of this unit were
that it be readily transportable, relatively straightforward to
operate, fully self-contained in terms of power requirements and
supporting supplies (disposables, surgical instruments, medications,
etc.), and that it be capable of meeting the normothermic metabolic
demands of the average adult.
"The primary purpose of the MALSS is to allow for field
cardiopulmonary support by extracorporeal perfusion. However,
because of the necessity to await the pronouncement of clinical death
imposed by current legal constraints, preparation of the patient for
extracorporeal support must begin after respiratory and cardiac
arrest. In order to minimize ischemic damage during the interval
between pronouncement of legal death and the start of extracorporeal
support it is necessary to administer CPR. While it is anticipated
that under most circumstances femoral cutdown and initiation of
bypass can be undertaken with 15 to 30 minutes of legal death, it is
still necessary to have mechanical adjuncts for CPR available in
order to maximize use of the extremely limited number of personnel
available in a field setting."
The first MALSS, constructed in 1986 at Cryovita Laboratories (Note:
Until 1992 Cryovita Laboratories and Alcor were closely associated and in
the same buildings.) by Jerry Leaf, Hugh Hixon and Mike Darwin, has gone
through a number of major modifications. It began life as a Travenol Life
Support Gurney, with an aluminum frame, an integral Brunswick HLR, two "E"
oxygen cylinders, three storage drawers, and a mount for a cardiac
monitor/defibrillator. At that time we added a blood pump, batteries, a
charger, and an air compressor/vacuum pump. This equipment load caused
the frame to bend alarmingly, and part of the frame was replaced with
steel. More recently, the wheels were replaced because they were failing
under the weight of the MALSS. Later modifications were the replacement
of the Brunswick HLR with the more effective Michigan Instruments HLR, the
mounting of an ice bath, and a system for circulating ice water over the
patient. Eventually, its ready-to-go weight reached 510 lbs., to which
would be added the weight of the patient and the ice load. "Easily
transportable" was a fantasy until Alcor added a custom lift gate to its
ambulance. This "Mark 1" MALSS is currently being modified by Cryovita to
approximately a Mark 1, Mod 3 version.
The MALSS recently completed at Alcor, dubbed the "Mark 3", is the
logical extension of the original Mark 1, done on a clean slate. We have
succeeded in implementing many major (and minor) improvments while giving
up relatively little:
* The new steel frame is not only stronger and more durable than the
aluminum, steel and PVC tubing combination of the original, it was custom
designed and constructed around essential features of the whole unit (form
follows function!). And it is designed to integrate into the ambulance.
* The frame is constructed such that the 7'1" ice bath can be shortened by
nearly a foot on the spot. (A tight elevator ride on one patient
transport convinced us that this is a good idea.) Because of the steel
frame, the PIB has a larger internal capacity, despite almost identical
external dimensions.
* All components are secured within the frame profile: this prevents
the perfusion circuit and equipment from being scraped off going through
doorways and from the inevitable collisions with walls and furniture. The
consequence of this is that the perfusion tubing circuit can be strung
when time is less critical, in advance of the pronouncement of the
patient's legal death.
* The control panel and blood pump placement are designed to ease
stringing of the pump. The perfusion circuit mounting board can be swung
out for stringing and locked back within the profile (while strung), again
reducing preparation time.
* With the more efficient configuration of equipment, more on-board
storage capacity is available in large-capacity removable drawers.
* The oxygen cylinders hold 7,000-liters of oxygen (compared to 1,256
liters previously). This gives the HLR of the Mark 3 an unsupported
endurance of about an hour. This can be readily extended by connecting
the MALSS to hospital oxygen, the ambulance oxygen system, or separate
cylinders.
* The Mark 3's electrical components use all 110 volt power, supplied
either from the wall or from a 1200 watt inverter powered by an 80 ampere-
hour, 12 volt gel battery; or by the ambulance 12 volt system. This is a
major improvement over the perverse and inflexible 12/24 volt system
demanded by the 24 volt roller pump of the Mark 1 and allows the Mark 3 to
be fully supported by the ambulance. An on-board ammeter allows
estimation of battery drain.
* The icewater circulating pump pumps faster, and the distribution system
contains improvements recommended by Alcor member Robert Cardwell, such as
non-splashing flow spreaders.
* The orientation of the original MALSS with the patient's head at the
rear of the ambulance has been corrected so that activities in the
ambulance are a lot easier. Also because of this, the ambulance lift gate
has been shortened 17", easing the strain on its mounts.
* And finally, the professional paint job is not only durable, it makes
the Mark 3 MALSS look very professional! (Credit to Mike Darwin for
suggesting powder coating.)
These advances did not come without some sacrifices: Unassisted
battery endurance is less (about an hour and a half under full load);
however, we have never experienced, nor do we expect, a MALSS transport
where the trip from the point of disconnection from AC power to the
ambulance -- or vice versa -- would take more than a few minutes. Due to
a design error, the wheels are smaller than preference (by 2"), but they
yield more manueverability than we had with the original model because
they are not overstressed. Finally, the Mark 3 weighs more than the
original (625 lbs. vs. 510).
The Mark 3 MALSS was designed and built entirely in-house at Alcor.
Tanya Jones, Scott Hermann, and Keith Henson were major contributors to
the effort which was spearheaded by Hugh Hixon. Hugh also gets many
thanks for having advanced the most of the cost out of pocket (this
allowed the project to proceed without regard to transient cash flow
concerns). Hugh also purchased the equipment for a small but complete
welding shop in aid of this and other development and prototyping projects
at Alcor. One of these is a much-improved portable ice bath (PIB) design.
(Historical note: The "Mark 2 MALSS" is an uncompleted unit built by
Keith Henson. Its salient points are its organization into separate
components (of an ice bath, mechanical section, and dolly) to make it
transportable in a station wagon, and, more important, its welded steel-
frame construction. As funds become available, this unit will be
completed and deployed in Northern California.)
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