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A Case Study on Ischaemic Stroke and a summary of Emergency Paramedics and Non Emergency Ambulance Attendants treatment of the stroke patient.

At 0857 on the 7th of September 2011, an elderly gentleman called 000 and reported that he needed an ambulance for his 81yo wife who was lying on the bedroom floor unconscious. Approximately 10 minutes prior to the 000 call to Ambulance Victoria she was normal and up eating breakfast. At 0858 AV dispatched the case to the day shift paramedic crew at Mordialloc branch. This case was dispatched as 81yo female unconscious/ fainting with cardiac history, code 1 time critical. At 0903 the Paramedics were on scene.

On arrival at scene, the paramedics were greeted by the husband and directed to the bedroom were his wife was. On entering the room the paramedics conducted the primary survey and found ‘no immediate life threat’.

The 81yo female patient was lying on the floor unconscious with a clear airway and breathing. Drawing on her experience and knowledge, the treating paramedic assumed that this patient had had a stroke. The patient was moved to the bed for examination and treatment. At 0914 the patient was loaded into the ambulance and transported to Monash Medical Centre emergency on a signal 1. At 0925 the receiving hospital was notified of the patient’s condition and estimated time of arrival. Arrival was at 0935 and patient was off stretcher at 0959.

This case study will be focussing on the presentation and pathophysiology of ischaemic stroke and the difference in the treatment provided by emergency ambulance and non emergency ambulance. Pathophysiology, Signs, Symptoms and Risk Factors for Stroke.

The aforementioned patient on presentation had the following common medical history and Risk Factors for an ischaemic stroke:

An altered conscious state (Unconscious ,GCS 7) High blood pressure (160/80) Atrial fibrillation (Pulse 92 irregular) Pupils (left normal and reactive, right pinpoint and non-reactive) Right sided hemiparesis A history of: Type 2 diabetes, hypertension, transient ischaemic attack, and atrial fibrillation. Age 81

To fully understand why this patient’s medical history and presentation are high risk factors for ischaemic stroke, we must first have a basic understanding of the pathophysiology of stroke.

Stroke is a serious neurological disease, and constitutes a major cause of death and disability throughout the world. The pathophysiology of stroke is complex, and involves excitotoxicity mechanisms, inflammatory pathways, oxidative damage, ionic imbalances, apoptosis, angiogenesis and neuroprotection. The ultimate result of ischemic cascade initiated by acute stroke is neuronal death along with an irreversible loss of neuronal function.( Prabal Deb; Suash Sharma & K.M. Hassan, 2009)

A stroke is a sudden interruption of blood flow to part of the brain. This interruption of blood flow can be caused by either ishaemia or haemorrhage. Both of these types of strokes may result in neurological deficits and brain cell death

An ischaemic stroke occurs when partially or totally occluded vessels in the brain deprive the cells of oxygen, causing hypoxia of the brain cells and initiating what is called an “ischemic cascade”. Because of this occlusion aerobic respiration can no longer take place to produce energy (glucose). The ischaemic area of the brain will resort to anaerobic respiration to create the energy required to maintain cellular and neurological function. During anaerobic respiration, less energy is produced and the by product lactic acid is created. Lactic acid can have a detrimental and potentially lethal effect on brain cells by disrupting the normal acid base balance.

As the ischaemic cascade continues from oxygen or glucose depletion, it adversely affects the energy dependant process of the cells and leads to cellular injury and death.

Various diseases can lead to ischaemic strokes. However the most common cause of an ischaemic stroke is the narrowing of the arteries in the neck or head due to atherosclerosis. Atherosclerosis is the hardening and narrowing of the arteries, mainly due to the build-up of fat and cholesterol, which then form plaques. When the arteries become too narrow, blood cells may collect and form blood clots (thrombus). When these blood clots block the artery where they are formed it is called a thrombosis, or if these blood clots and or plaques dislodge and become trapped and occlude arteries elsewhere in the body it is called an embolism.

There are two types of ischemic stroke, which are classified by the way they block blood vessels in the brain. A thrombotic stroke occurs when a vessel in the brain is occluded and blood flow is halted to the distal area of the occlusion site, due to a local thrombosis. An embolic stroke occurs when a vessel is occluded by a foreign substance (embolus). This embolus can be a piece of ruptured plaque or a dislodged blood clot from elsewhere in the blood stream, which is pushed through the blood vessels to the brain. The embolus will continue to travel until it reaches vessels which are too small for it to pass. This is when it blocks the vessels and creates an embolism which is the cause of an embolic stroke.

Other common causes of ischaemic stroke can be atrial fibrillation, myocardial infarction or abnormalities of the heart valves. When blood is not efficiently moved through the heart it can form blood clots (thrombus). The thrombus can break loose and move to other parts of the body. If these blood clots travel to and block an artery in the brain, they will cause an embolism. “There are many other possible causes. Examples include use of street drugs, traumatic injury to the blood vessels of the neck, or disorders of blood clotting.” (The Internet Stroke Center, 2010)

A haemorrhagic stroke mainly occurs when a blood vessel in the brain bursts due to atherosclerosis, high blood pressure or a congenital malformation. A burst vessel causes bleeding into the brain and decreased blood flow in the damaged vessel. Blood build up increases pressure in the brain damaging cellular tissue and collapsing smaller vessels,

The treating paramedic believed the patient had presented with an ischaemic stroke because of the patients previous medical history and the following common risk factors:

81 years old. Stroke risk increases with age, doubles every 10 years after the age of 55 History of TIA, or prior stroke High Blood Pressure Atrial Fibrillation Due to the patient’s medication, she most likely has other common risk factors of; Diabetes History of High Cholesterol Carotid Artery Disease

Other risk factors for Ischaemic stroke; Lack of Physical activity, obesity, smoking and alcohol abuse Race and socio-economic standing is also a risk factor but presents differently in various countries.

Stroke symptoms typically start suddenly, over seconds to minutes. The symptoms depend on the area of the brain affected. “The more extensive the area of the brain affected the more functions that are likely to be lost.”( Stroke, n.d.)

A person may present with one or more of the following Signs and symptoms of stroke;

Weakness or paralysis of the face, arm or leg Poor balance and or coordination Difficulty speaking or understanding Difficulty swallowing Problems with sight (blurred, double or loss) Numbness or loss of feeling down one side of the body

In Australia ischaemic strokes represent approximately 80% to 85% of all strokes.

Stroke is Australia’s second single greatest killer after coronary heart disease and a leading cause of disability. In 2011, Australians will suffer around 60,000 new and recurrent strokes – that’s one stroke every 10 minutes. One in five people having a first-ever stroke die within one month and one in three die within a year. The number of strokes will increase each year due to the ageing population unless something is done to reduce the incidence rate. In the next ten years more than half a million people will suffer a stroke. About 88% of stroke survivors live at home and most have a disability. Close to 20% of all strokes occur to people under 55 years old. (Facts, figures and statistics, n.d. )

The pre-hospital treatment of a patient that presents with a suspected stroke differs little between Paramedics (PM) and Ambulance Transport Attendants (ATA). On arrival at scene both the emergency and non emergency practitioners will complete the clinical approach and primary survey. This is defined in the Ambulance Victoria Clinical Practice Guidelines (2010)

• Dangers, Response, Airway, Breathing, Circulation, Defibrillation

At this stage if necessary the ATA would manage the patient’s airway with an oropharyngeal airway. The PM however may chose to manage the patient’s airway with a laryngeal airway The primary survey is the corner stone of emergency care and should be the first priority in stroke management, as it should be in any other emergency first aid/response situation.

Once the patient is stabilised a full set of vital signs survey will be completed including a Glasgow Coma Score. At this stage the PM will also complete a stroke assessment as defined in AV Clinical Practice Guidelines (2010).As a part of the patient’s initial management they will be cardiac monitored and administered oxygen at 8 L/PM via face mask. Both PM’s and ATA’s should obtain a focused history which includes an accurate timeframe for the onset of symptoms. This will help in the decision of what treatment path the receiving hospital will take.

According to the Clinical Practice Guidelines, this patient would be an Actual Time Critical Patient. AV Clinical Practice Guidelines (2010), that requires immediate signal 1 transport to a suitable receiving emergency department. The PM gives a Situation report (SitRep) to there dispatch on the patient’s condition, and may receive MICA backup. If it is in the patient’s best interest to be transported by the attending PM crew, they will communicate with the receiving hospital to advise them of the patient’s condition and onset of the stroke. This will allow the receiving hospital to manage the patient for their best outcome.

According to the Non-emergency patient transport, Clinical practice protocols Non-emergency patient transport (2006), this patient is a ‘time critical’ ‘emergency patient’ who may not be transported by NEPT. If the ATA was on a private shift they would communicate with their dispatch or call 000 requesting an emergency ambulance rondevu to transport this patient. If the ATA was on a AV shift they would communicate with the clinician who would instruct them to either wait, or rondevu with emergency ambulance, or too transport to hospital.

The differences between emergency ambulance and non emergency patient transport are clearly defined. Emergency ambulance paramedic’s work within guidelines that allow them to treat and manage ‘Time Critical’ and ‘Emergent Time Critical’ patients using their knowledge and skills gained over 3 years of intensive study and scenarios. In NEPT we practice within protocols that give us a consistent framework for a minimum level of knowledge, education and training that allows us to practice at a high level of first aid for good patient outcomes. However in this case study on stroke we find that the role of emergency ambulance and NEPT can overlap to allow for the best treatment of the emergency patient. In this case transport is treatment.

References: Deb, P., Sharma, S., & Hassan, K. (2009). Pathophysiologic mechanisms of acute ischemic stroke: An overview with emphasis on therapeutic significance beyond thrombolysis. Retrieved from http://home.kku.ac.th/korawut/stroke/2010-Pathopysiology%20stroke.pdf The Internet Stroke Center. (2010). About Stroke. Retrieved from http://www.strokecenter.org/patients/ais.htm Stroke. (n.d.). Retrieved from http://www.anri.org.au/disorders/2-main-category/68-stroke.html Facts, figures and statistics. (n.d. ). Retrieved from http://www.strokefoundation.com.au/facts-figures-and-stats Ambulance Victoria (2010) Clinical Approach. Clinical Practice Guidelines, CPG A0101. Retrieved October 1, 2011 from http://www.ambulance.vic.gov.au/Media/docs/AV_1_CPG_PRELIMS-watermark-9d923d19-156a-4702-8637-25477c50d09b-0.pdf Ambulance Victoria (2010) Stroke Assessment. Clinical Practice Guidelines, CPG A0107. Retrieved October 1, 2011 from http://www.ambulance.vic.gov.au/Media/docs/AV_1_CPG_PRELIMS-watermark-9d923d19-156a-4702-8637-25477c50d09b-0.pdf Non-emergency patient transport (2006) Clinical Practice Guidelines, (pp.9 & 67)


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