آموزشی, دستگاه ها پزشکی, سایر دستگاه ها, ونتیلاتور

ونتیلاتور

دستگاه ونیتلاتور

ونتیلاتور

ونتیلاتور چیست : ونتیلاتور دستگاهی است که کار تنفس مصنوعی را برای بیمارانی که به طور موقت یا دائم
دچار مشکلات تنفســــی هستند، انجام می دهد. به طور کلی هر بیماری که سیستم تنفســــی وی نتواند
پاسخگوی نیازهای نفسی اش باشد، نیازمند سیستم کمک تنفسی است. چنین سیستمی عمدتاً در بیماری
های قلبی-ریوی مورد نیاز واقع می شود و این دستــــگاه معمولا در بخش های CCU ،ICU NICU ، و اورژانس
وجود دارد.

نحوه عملکرد ونتیلاتور

 ورودی دستگاه ونتیلاتور دو گاز هوا و اکسیژن تحت  فشاراست.هوای فشرده یا از طریق کمپرسور دستگاه و یا
از طریق سانترال تأمین شده و اکسیژن نیز به صورت فشرده و یا از طریق اکسیژن مرکزی بیمارستان تأمین می
شود.دستگاه ونتیلاتور اکسیــــژن و هوارا به میزان مورد نیازبدن باهم ترکیب نموده و سپـــس توسط تیوپ های
مخصوصی تحت عنوان ” مدار تنفسی ” به بیمار تحویل می دهد.
ونتیلاتور چیست

ونتیلاتور

گاز(هوا و اکسیژن ) موجود در این دستگاه قبل از تحویل به بیمار تبدیل به بخـــارآب مرطوب شده و سپس از
طریق مدار تنفسی منتقل می شود.بخار آب توسط بخشی دستگاهی بنام مرطوب کننده تولید شده و وارد
مدار تنفسی یا همان ” ست ونتیلاتور” می شود.
ونتیلاتور به منظور وارد کردن هوا به درون ریه ها جهت انجام عمل دم، فشار موجود درمدار تنفسی را افزایش
می دهد.همچنین با کم کردن فشار باعث می شود هوای بازگردانده شده از ریه ها یا هوای بازدم،به بیرون از
بدن (هوای بیرون) منتقل گردد.

انواع ونتیلاتور

  • ونتیلاتورهای قابل حمل (پرتابل )

ونتیلاتور پرتابل

این ونتیلاتور کوچک ودر عین حال بسیار قوی است و می تواند به صورت پنوماتیکی (با پمپ هوا ) یا از طریق
برق AC  یا منبع برق DC نیرو بگیرد.
  • ونتیلاتور ICU
ونتیلاتور ICU

ونتیلاتور ICU

این ونتیلاتورها بزرگ تر بوده و معمولا به طور پیوسته به برق AC  متصل هستند و همچنین دارای باتری جهت
سهولت حمل و نقل های داخلی می باشد. این مدل از ونتیـــلاتورها اغلب دارای تنوع مد زیادی هستنـــد به
طوری که برای هر نوع شرایط بیمار در ICU  قابل استفاده هستند.
همچنین این نوع ونتیلاتورها قابلیت نمایش پارامترهای مختلف تنفسی بیماررا دارند از جمله نرخ تنفس بیمار،
حجم بازدمی بیمار، میزان حجم دقیقه ای ، و در بعضی مدل ها میزان دی اکسید کربن بازدمی بیمار (مشابه
دستگاه کاپنوگراف) نیز نمایش داده می شود. البته در بعضی ونتیلاتورهای قابل حمل (پرتابل) پیشرفته نیز این
قابلیت ها تا حد زیادی دیده می شوند.

Medical ventilator

A medical ventilator (or simply ventilator in context) is a machine designed to provide mechanical
ventilation by moving breathable air into and out of the lungs, to deliver breaths to a patient who is
physically unable to breathe, or breathing insufficiently.
While modern ventilators are computerized machines, patients can be ventilated with a simple,
hand-operated bag valve mask.
Ventilators are chiefly used in intensive care medicine, home care, and emergency medicine (as
standalone units) and in anesthesiology (as a component of an anesthesia machine).
Medical ventilators are sometimes colloquially called “respirators”, a term stemming from commonly
used devices in the 1950s (particularly the “Bird Respirator”). However, in modern hospital and
medical terminology, these machines are never referred to as respirators, and use of “respirator” in
this context is now a deprecated anachronism signaling technical unfamiliarity. In the present-day
medical field, the word “respirator” refers to a protective face mask.

Function

In its simplest form, a modern positive pressure ventilator consists of a compressible air reservoir or
turbine, air and oxygen supplies, a set of valves and tubes, and a disposable or reusable “patient
circuit”. The air reservoir is pneumatically compressed several times a minute to deliver room-air, or
in most cases, an air/oxygen mixture to the patient. If a turbine is used, the turbine pushes air
through the ventilator, with a flow valve adjusting pressure to meet patient-specific parameters.
When over pressure is released, the patient will exhale passively due to the lungs’ elasticity, the
exhaled air being released usually through a one-way valve within the patient circuit called the
patient manifold.
Ventilators may also be equipped with monitoring and alarm systems for patient-related parameters
(e.g. pressure, volume, and flow) and ventilator function (e.g. air leakage, power failure, mechanical
failure), backup batteries, oxygen tanks, and remote control. The pneumatic system is nowadays
often replaced by a computer-controlled turbopump.
Modern ventilators are electronically controlled by a small embedded system to allow exact
adaptation of pressure and flow characteristics to an individual patient’s needs. Fine-tuned ventilator
settings also serve to make ventilation more tolerable and comfortable for the patient.

Life-critical system

Because failure may result in death, mechanical ventilation systems are classified as a life-critical
system, and precautions must be taken to ensure that they are highly reliable, including their power-
supply.
Mechanical ventilators are therefore carefully designed so that no single point of failure can
endanger the patient. They may have manual backup mechanisms to enable hand-driven respiration
in the absence of power (such as the mechanical ventilator integrated into an anaesthetic machine).
They may also have safety valves, which open to atmosphere in the absence of power to act as an
anti-suffocation valve for spontaneous breathing of the patient. Some systems are also equipped
with compressed-gas tanks, air compressors, and/or backup batteries to provide ventilation in case
of power failure or defective gas supplies, and methods to operate or call for help if their
mechanisms or software fail.

History

The history of mechanical ventilation begins with various versions of what was eventually called the
iron lung, a form of noninvasive negative pressure ventilator widely used during the polio epidemics
of the 20th century after the introduction of the “Drinker respirator” in 1928, improvements
introduced by John Haven Emerson in 1931, and the Both respirator in 1937. Other forms of
noninvasive ventilators, also used
widely for polio patients, include Biphasic Cuirass Ventilation, the rocking bed, and rather primitive
positive pressure machines.
In 1949, John Haven Emerson developed a mechanical assister for anesthesia with the cooperation
of the anesthesia department at Harvard University. Mechanical ventilators began to be used
increasingly in anesthesia and intensive care during the 1950s. Their development was stimulated
both by the need to treat polio patients and the increasing use of muscle relaxants during
anesthesia. Relaxant drugs paralyze the patient and improve operating conditions for the surgeon
but also paralyze the respiratory muscles.
An East-Radcliffe respirator model from the mid-20th century

An East-Radcliffe respirator model from the mid-20th century

In the United Kingdom, the East Radcliffe and Beaver models were early examples, the latter using
an automotive wiper motor to drive the bellows used to inflate the lungs. Electric motors were,
however, a problem in the operating theatres of that time, as their use caused an explosion hazard
in the presence of flammable anesthetics such as ether and cyclopropane. In 1952, Roger Manley of
the Westminster Hospital, London, developed a ventilator which was entirely gas driven, and became
the most popular model used in Europe. It was an elegant design, and became a great favourite
with European anesthetists for four decades, prior to the introduction of models controlled by
electronics. It was independent of electrical power, and caused no explosion hazard. The original
Mark I unit was developed to become the Manley Mark II in collaboration with the Blease company,
who manufactured many thousands of these units. Its principle of operation was very simple, an
incoming gas flow was used to lift a weighted bellows unit, which fell intermittently under gravity,
forcing breathing gases into the patient’s lungs. The inflation pressure could be varied by sliding the
movable weight on top of the bellows. The volume of gas delivered was adjustable using a curved
slider, which restricted bellows excursion.

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