Therapeutic Hypothermia Post Cardiac Arrest (Essay Sample)

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Therapeutic Hypothermia Post Cardiac Arrest
Introduction
Therapeutic hypothermia so far has been used successfully during cardiac arrest surgery. Its main use is to protect against global cerebral ischemia. It is referred as protective hypothermia. It is administered to a patient in order to lower his or her body temperature. The temperature is reduced in order to help in reducing tissue destruction or injury in the case of poor blood flow or lack of blood flow. Cardiac arrest is one of the major causes of lack of blood flow. Poor blood flow is also induced by blockage of an artery by an embolism. It happens in cases such as when a person has stroke. In resent research, therapeutic hypothermia has proved to improve survival and brain function in the case following resuscitation from cardiac arrest. Even so, disputed claims were put up against its use indicating that a temperature of 36 centigrade’s would result in the same mortality and the same brain function outcome at a temperature of 33 centigrade’s.
Medical usage
Hypothermic therapies are used in a broad array of treatment. They are effectively effected in five categories namely cardiac arrest, and ischemic among the rest. The current American laws support the use of hypothermic therapies following resuscitation from cardiac arrest. The recommendations to its use were based on two recommendations. The first recommendation was after the 2002 trial that automatically showed improvement in survival and brain function when cooling between 32 °C (90 °F) to 34 °C (93 °F) for cardiac arrest patients (Edgren et al. 59). After that two new studies were out forward with criticism on whether the method was appropriate use after cardiac arrest. However, the trials that took place in November 2013 showed no difference between earlier cooling and after cooling. One of its greatest disadvantages is that it increases the possibilities of a patient contracting pneumonia and sepsis however it does not lead to an overall risk of infection (Oka et al. 52).
The earlier rationale focused on effects of hypothermia as a neuroprotectant in its function to slow cellular metabolism as a result of dropping body temperatures. It is measured that a drop in every one degree Celsius drop in body temperature, cellular metabolism drops by 5.7 %. Most research suggests that hypothermia reduces the negative effects of ischemia. It decreases the body need for oxygen hence reducing the negative effects. The medical methods involved are invasive and non-invasive. When a patient is facing possibilities of ischemic injury therapeutic hypothermia should be initiated (Edgren et al. 59). During the invasive method, cooling catheters are inserted into the femoral vain. After insertion, a cool saline solution is circulated either through a metal coated tube or a balloon in the catheter. The saline solution will act as a coolant that will cool the body temperatures of the affected. It lowers the temperature to the required standards. 1.5 °C (2.7 °F) - 2 °C (3.6 °F) per hour is the ranges within which the catheters reduce the temperature in the method. They have very distinct levels of accuracy such that there are no mistakes or unpredicted results when the method works correctly. Even so there are a number of adverse events associated with this method. These events include bleeding, infections, vascular puncture and deep vein thrombosis. The infections caused by the cooling catheter are known to be very harmful. The harm is associated with the critical conditions of a patient and the vulnerability windows. Bleeding is as a response to the decreased clotting threshold (Oka et al. 60).
Non invasive is where modern technologies are involved in the cooling process. The technologies are designed and named such as water blankets, torso vest or leg wraps. Cold water is made to circulate through a blanket or torso wraparound vest and leg wraps. 70 % of the patient’s surface is covered with the water blanket in order to lower the temperatures. Water blankets act as coolants hence they lower the temperature of the patient by controlling the body temperatures. Even so there are several drawbacks observed in the technique (Edgren et al. 59). The first drawback is that the blanket is susceptible to leaking. The idea presents a great electrical hazard due to the close proximity with electricity. The blankets are also said to create burns on the skin of the patient. Other problems associated with the blanket include shooting of temperatures and slower induction time as compared to internal cooling (Oka et al. 61).
Positive effects and negative effects
Cardiac arrest is sudden circulatory standstill and is a common means through which patients meet their deaths. Survivors of cardiac arrest have a high significant neurological injury. It is estimated that about 10 to 20 % are discharged with no defects at all.
Among the advantages is that hypothermia slows most metabolic processes and inhibit deleterious biochemical cerebrovascular processes. The processes are witnessed in experimental models after ischemic cerebral insults and reperfusion. Inducing mild hypothermia leads to the decrease in the amount of free radicals produced. Consequently, it leads to the slowing of the destructive processes caused by cardiac arrest. The reduction in free radical generation facilitates antioxidant defense mechanisms of the brain to carry out their functions without being inundated (Oka et al. 66).
Another advantage observed by the use of therapeutic hypothermia is the suppression of inflammatory cytokines. The inflammatory responses are witnessed in hypoxic brain injury. They are caused by the release of the pro-inflammatory cytokines. Hypothermia also reduces inflammation. It is reduced since hypothermia suppresses free radical production. If the radical production is left free, it leads to further inflammation through lipid peroxidation and leukotrienes production (Edgren et al. 59).
Another advantage as witnessed is that hypothermia therapy reduces ion homeostasis. It also slows the accumulation of glutamate or even blocks it. Per se, it leads to reduction in neuro-excitability and sometimes death (Trayston et al. 95).
Observations indicate that hypothermia influences most mechanisms causing neurological injury during the period of hypoxia and reperfusion. Per se, it strongly suggests that therapeutically hypothermia is an attractive treatment for post cardiac treatment.
The first cases to be documented under the use of therapeutic hypothermia were done in 1958. The constituents were four patients who had good neurological outcome after cardiac arrest. The four patients were given heart massages and their temperatures were cooled to 30-34 degrees Celsius (Oka et al. 66). Other cases were reported in the year 1998. The patients, after the return of spontaneous circulation following out of hospital cardiac arrest, were cooled and maintained at 32-22 degrees Celsius. They were re-warmed slowly and afterwards they showed positive neurological recovery despite the prolonged periods of cardiac arrest (Edgren et al. 59).
The side effects of therapeutic hypothermia are potent...