Extracorporeal Membrane Oxygenation (ECMO)

Extracorporeal Membrane Oxygenation, or ECMO for short, is an advanced therapy that is sometimes used to treat people with life-threatening heart and lung failure, to do the work of the heart and lungs when a patient’s own organs are too sick or weak to work on their own. It is effectively a modified heart-lung bypass machine—a machine that takes over heart and lung function (meaning it adds oxygen to and removes carbon dioxide from a patient’s blood supply). 

 But unlike a heart-lung bypass machine, which is designed for short-term use (during heart surgery, for instance), ECMO machines provide long-term heart and lung support over a period of hours, days, or even weeks to give a patient’s heart and lungs time to heal and regain function. It provides a kind of bridge, a temporarily replacement that keeps the functions of the heart and lungs going while doctors treat the underlying problem.

ECMO can be used for patients of all ages, from infants to adults. It can help patients with a range of severe heart and lung conditions, from cardiac arrest to respiratory failure. But in most cases, ECMO therapy is used only when all other conventional treatments have failed to resolve the underlying heart or lung disorders.  

ECMO Machine

The complete ECMO Machine 

 

 

 

 

 

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Connecting To ECMO

Connecting a patient to the ECMO machine requires surgery. The ECMO machine connects to a patient through plastic tubes called cannulas. After giving the patient an anticoagulant, a medication that prevents blood from clotting, the doctor inserts cannulas into large arteries and veins located in the chest, neck, or legs. Once connected, the ECMO machine draws blood from the patient, which it then passes through the cannulas and into an artificial lung that infuses the blood with oxygen and removes carbon dioxide. The ECMO machine then warms this treated blood to body temperature and pumps it back into the patient. In cases where a patient’s heart cannot circulate blood on its own, a mechanical pump takes over the heart’s role and pumps blood through the patient’s circulatory system.

ECMO therapy is frequently a treatment of last resort. It is recommended when other treatments have failed to resolve the underlying problem, but there is still a possibility of recovery. 

The doctors continue to administer sedatives and pain medications after surgery to keep patients as comfortable and pain-free as possible, perform routine chest X-rays, run regular blood tests to assess oxygen and carbon dioxide levels that allow doctors to evaluate and track the patient’s lung and heart health and to check for possible infections.

Basic setting up of the ECMO

Connecting to a patient

Applications

While there is no fixed list of conditions for which ECMO is used, doctors may recommend its use in the following situations:

• Respiratory failure (when the lungs fail to maintain adequate oxygen levels or remove enough carbon dioxide from the blood)
• Heart transplantation
• Lung transplantation
• Cardiac arrest (when the heart fails to pump blood effectively)
• Cardiogenic shock (when the ventricles of the heart do not function properly, resulting in insufficient blood flow)
• Pulmonary embolism (when an artery in the lungs is blocked)
• Birth defects of the heart
• Acute Respiratory Distress Syndrome, ARDS (a type of respiratory failure that prevents adequate oxygen from getting to the lungs and blood)

 

Why Is ECMO used in some COVID-19 Patients?

Some people severely affected by COVID-19 develop a life-threatening lung condition called acute respiratory distress syndrome, or ARDS for short. People with ARDS struggle to get enough oxygen into their lungs and blood due to a buildup of fluid in air sacs called alveoli. Some COVID-19 patients with ARDS who do not respond to conventional treatment may benefit from ECMO therapy. 

In general, doctors aim to take patients off ECMO therapy as quickly as possible. Because it is used for patients with a range of conditions, each with its own recovery timetable, the length of time someone is on ECMO therapy can vary greatly. Some patients need it for only a few hours while others may require days or weeks of ECMO support.

 

Once the patient reaches a point at which the ECMO machine is no longer necessary, the ECMO team will begin the process of weaning in which they steadily decrease the patient’s blood flow through the machine. Over several hours, they track the patient’s response to this reduction in ECMO support. If the patient responds well, and the ECMO team concludes that discontinuation of ECMO is safe, a surgeon will remove the cannulas. 

 

After coming off ECMO, a patient might require a ventilator to provide breathing support. As soon as the patient is able to breathe without assistance, doctors will remove the ventilator. But patients may still need to stay in the hospital for days or weeks, at least until vital signs are stable. Many will also need physical therapy to help regain muscle strength, as well as speech therapy to aid recovery after long-term use of a ventilator’s breathing tube.  

  

                                            Ref: Youtube.com: "I almost died" by CNA

What are the risks associated with ECMO?

ECMO therapy itself comes with its own set of risks including:

• Bleeding: Bleeding affects up to 50% of ECMO patients and, in some cases, can be life-threatening. ECMO therapy requires the use of anticoagulants, medications that thin the blood (and prevent the formation of clots) to keep the blood flowing through the body and ECMO machine. But these medications also increase the likelihood of excess bleeding. As a result, hemorrhaging may occur in a number of places, including the lungs, stomach, mouth, nose, and brain. Doctors watch for signs of bleeding; medication or surgery may be necessary to stop it.
• Kidney Failure: In some cases, patients on ECMO do not circulate enough blood to their kidneys, resulting in kidney failure and the potential need for dialysis, a machine that does some of the work normally done by kidneys. Kidney function usually returns after the patient is removed from the ECMO machine, though sometimes the kidneys do not recover, and the patient will require lifelong dialysis treatment.
• Bacterial Infection: Because cannulas are inserted into veins and arteries in ECMO therapy, bacteria can have direct access to the patient’s blood stream. If unchecked, infections may result, such as bacterial pneumonia. If infection is suspected, patients are treated with a course of antibiotics and cannulas may be replaced.
• Stroke: In rare cases, ECMO patients develop small blood clots that can reduce the flow of blood to the brain. This raises risk for stroke.  
• Pulmonary Embolism: Though it is rare, some patients on ECMO develop a blood clot that blocks blood flow in the lungs. Pulmonary embolism can cause permanent damage to the lungs, as well as damage to other organs as the lungs may be unable to provide enough oxygen to the body.  

         

            Reference: www.yalemedicine.org/conditions/ecmo

Note: Information on this page is provided for interest only on a 'best effort' basis and does not constitute personal advice. Always discuss medical conditions and related mattyers with your doctor(s).

PROTON THERAPY

Proton beam therapy is a type of radiotherapy that uses a beam of high energy protons, which are small parts of atoms, rather than high energy x-rays (called “photons”) to treat specific types of cancer.
Proton beam therapy enables a dose of high energy protons to be precisely targeted at a tumour, reducing the damage to surrounding healthy tissues and vital organs which is an advantage in certain groups of patients or where the cancer is close to a critical part of the body such as the spinal cord.

Proton therapy cancer treatment begins when each proton begins its journey at the injector located within an electric field. In the field, hydrogen atoms then separate into negatively charged electrons and positively charged protons. The protons travel through a vacuum tube within a pre-accelerator. This process boosts their energy to two million electron volts. The protons continue in the vacuum tube and begin their high-speed journey in the synchrotron. They travel around the synchrotron about 10 million times per second. Each time they circulate, a radiofrequency cavity within the ring delivers a boost of energy. This increases the protons' energy to between 70 and 250 million electron volts. The voltage achieved is enough to place them at any depth within the human body.

Fig shows the superconducting Synchrotron and the Proton Beam Transport System

Beam Transport System

 
After leaving the synchrotron, the protons move through a beam transport system, continuing in the vacuum tube through a series of steering and focusing magnets that guide them to the proton treatment rooms. Each proton treatment room has a beam delivery system, or nozzle, is the last device the protons travel through before entering the body. The nozzle shapes and spreads out the proton beam in three dimensions. 

Fig above shows Proton Magnet focus the beam and direct it into each treatment room.

Radiation oncologists must determine location, shape, and tissue density of the target tumor before determining the number of protons to deliver. They must also calculate the depth that the protons must travel in order to calculate the speed and shape of the beam. These decisions render a beam that is highly accurate and practically ‘tailor made’ for a specific treatments.

Treatment Gantry of a Proton Therapy System

After leaving the nozzle, the protons enter the patient's body.

The equipment in the proton therapy treatment rooms vary based on the conditions treated. One proton treatment room may have a stationary beam with two branches – one branch for irradiating eye tumors and the other for central nervous system tumors and tumors of the head and neck. The other treatment rooms may have gantries – wheels that are 35 feet in diameter that revolve around the patient to direct the beam exactly where needed. From the patient's perspective, all that is visible is a revolving, cone-shaped device.

Proton beam therapy is only suitable for certain types of cancer, such as highly complex brain, head and neck cancers and sarcomas as it does not lead to better outcomes for many cancer cases than using high energy x-rays, which is still considered the most appropriate and effective treatment for the majority of cancers.

Like high energy x-ray radiotherapy, proton beam therapy is painless, but patients may experience side effects similar to those experienced from other forms of radiotherapy.

How Does Proton Therapy's Effectiveness Compare to IMRT or Other X-ray Treatments?

Because proton beams can be delivered in higher doses and with far more accuracy, proton therapy typically can control cancer with fewer treatments than IMRT. This pinpoint accuracy also results in fewer long-term side effects (since the radiation does not spill over and damage healthy tissue and organs) meaning that patients treated with proton therapy experience a higher post-treatment quality of life as compared to IMRT and even conventional x-ray treatments.

Is Proton Radiation Therapy Ever Combined?

Yes. Conformal proton therapy is often used in conjunction with X-ray therapy. This method boosts the dose to sites of gross disease and allows irradiation of a large tissue volume. Depending on the amount of cancer within a particular lymph node and type of cancer that is present, a patient may be at risk for harboring microscopic nests of cancer cells within the nodes. These nodes may lie at some distance from the primary tumor and may not be irradiated if conformal proton treatment alone is delivered to the tumor.
The objective of the treatment plan is to treat both the primary tumor and any areas where a microscopic tumor might hide. X-ray treatment alone will limit the total dose of radiation that can be given due to the high doses it delivers to large amounts of healthy tissue. Therefore, conformal proton radiation therapy is used to treat the primary tumor, and is then followed by X-ray therapy to treat the regional nodes. By giving some of the treatment with conformal protons, the total X-ray dose can be reduced substantially.
This reduces the risk of complications and permits treatment of potentially involved lymph nodes. Microscopic cancer within these nodes might be missed if X-rays were not used.

Side-Effect

Since proton therapy allows the radiation to unfold directly in the tumour, the surrounding tissue and organs are protected to the best of their ability. If a reaction – i. e. a side effect – occurs, only the irradiated body region is usually affected. This can lead to irritation of the skin or mucous membranes, which usually recede completely within two to three weeks after treatment. Sometimes, however, a kind of permanent scarring can also occur as a late consequence.

Information on this page is provided for interest only on a "best efforts" basis and does not 
constitute personal advice. Always discuss medical conditions and related matters with your doctor.
 

Reference: https://protons.com/proton-advantage/how-does-proton-therapy-work

HYBRID OPERATING ROOM

A hybrid operating room is where major procedures that combines a conventional surgical and interventional procedure guided by fluoroscopic or MRI imaging in a hybrid room without interruption.

Traditional fixed C-arms produce 2D fluoroscopy or 3D rotational angiography but with the advanced technology nowadays, C-arms are able to acquire CT-like 3D images and used for image guided surgery and also in intra-operative imaging like flow analysis. With these newer fluoroscopic C-arms where the device image intensifiers are of the digital flat panel detectors has thus enabled the fluoroscopy techniques to transit into three dimensional CT-like imaging capability.

Hybrid operating rooms are currently used mainly in cardiac, vascular and neurosurgery, but could be suitable for a number of other surgical disciplines.

PLANNING THE HYBRID ROOM

Before planning a hybrid operating room, a clear vision of the utilization should be established. It should address the requirements and the needs of various surgical specialties, procedures and workflow. To ensure a smooth workflow in the room, all parties working together should state their needs and requirements, which will impact the room design and determining various resources like space, medical, and imaging equipment. This may require professional project management and several iterations in the planning process with the vendor of the imaging system, as technical interdependencies are complex. The result is always an one solution tailored to the needs and preferences of the interdisciplinary team and the hospital.

Reference: hybridoperatingroom.com

LIGHTS, MONITORS AND OTHER DEVICES

Multiple movable and flexible booms need to be installed in the OR. If there are 2 booms to be installed, a boom of every side of the operating table should be considered to serve the operating team. Collision of the ceiling mounted display with the surgical lights or other ceiling mounted devices should be avoided. Large displays are now available and capable of integrating multiple video inputs on various sizes and therefore decreasing the needs for multiple screens. A dedicated ceiling plan with all ceiling-mounted components including air conditioning should be drawn to ensure the function and usability of all devices. 

The hybrid OR facilitates a whole new spectrum of cardiac surgical therapies, and will therefore become an essential resource of every cardiovascular centre. The trend towards hybrid OR is more of a revolution than an evolution due to the rapid integration into the surgical techniques. The hybrid OR itself represents an extreme complex working environment that demands careful planning by all stakeholders. Bundling all clinical, technical and architectural expertise as well as a realistic view of what is achievable is key for a successful hybrid OR project. 

Reference: cardenjennings.metapress.com & hybridoperatingroom.com & www.maquet-hybridoperatingroom