Aetiology and Definition of Cardiogenic Shock - Research Paper Example

Cardiogenic Shock: A Research Paper Abstract The research paper is aimed to present the definition of cardiogenic shock including the aetiology, causes and effects of the condition. In addition, the role of the critical care nurses which is essential to the treatment and management of the cardiogenic shock and related causes are also presented. Cardiogenic Shock: A Research Paper Cardiogenic shock is a type of cardiac condition wherein there is ‘insufficient tissue perfusion because of dysfunction.’ It is classified as one of the most difficult cardiac cases that medical professionals can face due to the significantly high rate of mortality, 50-80% (Bates, 2002, p.23). For that matter, it is important to determine the different aspects of the condition. The main objective of the research undertaken is to present the information pertinent to diagnosis, definition, aetiology, common presentation and treatment techniques of cardiogenic shock and the conditions associated with it. Another is to critically analyze the role of the critical care nurses in the provision of care specifically within the multidisciplinary working group in the critical care unit. Lastly, the research is aimed to present issues that can be considered to affect the treatment process. Aetiology and Definition of Cardiogenic Shock Cardiogenic shock can be determined through the different aspects of diagnosis. In terms of clinical definition, the condition can be observed as myocardial dysfunction due to diminished cardiac output. Another important clinical indication is the hypotension related to decreased tissue perfusion resulting to the change in mental functions and the decrease in the urine output or oliguria, which is approximately less than 30 mL/hour. In addition, the skin is cold and clammy (Bates, 2002, p.24; Hasdai, Berger and Battler, 2002, p.4). The myocardial performance is the primary symptom but other factors and clinical parameters that are hemodynamic are noted. Persistent hypotension of systolic blood pressure less than 90 mmHg for 30 minutes; decrease in cardiac index to less than 2.2 L/min/m2; and increase in pulmonary artery occlusion pressure to more than 15 mmHg (Bates, 2002, p.24). Incidence of Cardiogenic Shock Incidence of cardiogenic shock is significantly related to the cases of other heart cardiac conditions and abnormalities. For patients with myocardial infarction, there is a recorded 5% to 10% who suffered cardiogenic shock. It had been noted that the statistics were lower that the actual number due to the failure to record cases specifically when patients died prior to diagnosis (Hollenberg, Kavinsky and Parillo, 1999, p.47-48). State and Effects of Cardiogenic Shock There are different points related to state of cardiogenic shock. In terms of the mechanical aspect, the left area of the heart is significantly affected. A marked reduction of contractility and decrease of systolic pressure results to the less blood volume expelled from the heart for every beat. This would then result to comparatively high end-systolic volume which affects stroke volume negatively. After this, diastolic compliance decreases and both diastolic filing and end-diastolic pressure increase. The condition then commonly leads to pulmonary oedema due to high ventricular diastolic filling pressure and myocardial oxygen demand. These conditions will then result to low cardiac output due to increase in left ventricular and RV filling pressures. There is decrease in mixed venous oxygen and desaturation of arterial oxygen. (Alonso, Scheidt, Post and Killip, 1973; Dzavik et al., 1998; Hasdai, Berger and Battler, 2002, p.9; Sharma and Zevitz, 2008). The condition then would increasingly affect the capability of the heart, thus, it pumping becomes more difficult. This is due to the ‘imbalance between myocardial oxygen requirements and supply’ (Hasdai, Berger and Battler, 2002, p.9). The cardiogenic shock then would result to different changes in the cardiac functions which have detrimental effects to the different organ systems and vital functions of the body. One of the effects is the aggravation of cardiac conditions such as the myocardial ischemia due to hypotension and tachycardia. Systemic perfusion is another effect that can be attributed to the low cardiac output (Alonso, Scheidt, Post and Killip, 1973; Dzavik et al., 1998; Hasdai, Berger and Battler, 2002, p.9; Sharma and Zevitz, 2008). After the occurrence of cardiogenic shock, the body shifts into physiologic compensatory mechanisms to be able to support vital processes specifically in the heart and brain. In the process, anaerobic metabolism is activated, thus, there is accumulation of lactic acid that can still in turn affect the capability of the myocardium. Although there is temporary restoration of the heart rate and functions, renal fluid accumulates and can affect the condition of the body later on. Another negative affect is the exacerbation of myocardial ischemia due to different factors such as increase in myocardial oxygen demand, intensification of myocardial afterload and the onset of a deadly cycle that is needed to be treated. This can be attributed to the failure to meet the needs of the different organs in the body, thus, multisystem organ dysfunction syndrome can be the end result. Effects on the important organs such as the brain, heart and kidneys can be observed through symptoms such as confusion, agitation and even comma due to the effects on the brain; degrading cardiac functions due to the effects on the heart; and hypo perfusion and oliguria and renal failure due to the effects in the kidneys (Hasdai, Berger and Battler, 2002, p.9; Hasdai et al, 1999; Sharma and Zevitz, 2008). The state of cardiogenic shock than can be determined initially through the analysis of data gathered based on different physical parameters and through confirmed exclusion of conditions related to hypotension which include hypovolemia, haemorrhage, sepsis, pulmonary embolism, pericardial, aortic dissection or other pre-existing valvular diseases. Physical symptoms of the condition include rapid peripheral pulses which in cases of arrhythmias can be irregular. In addition, jugular venous distention and lung crackles are observable. Weak or distant heart beat with third or forth sounds can be perceived. In cases of tachycardia, the pulse pressure is low. Signs of hypoperfusion are evident while other symptoms can be associated to specific types of cardiac conditions (Sharma and Zevitz, 2008). Causes of Cardiogenic Shock There causes of the cardiogenic shock can be classified as a result of either myopathic or mechanical failure. 1. Myopathic Failure Myopathic causes are based on different issues. On the basis of pathophysiology and aetiology on the other hand, causes that are myopathic can be classified into systolic dysfunction, diastolic dysfunction, valvular dysfunction, cardiac arrhythmias and coronary artery disease (Sharma and Zevitz, 2008). The most common cause of the condition is acute myocardial infarction, although the cardiogenic shock can be resulting from the failure of any parts of the heart, thus affecting the myocardial functions which include ischemia, infarction, stunning, contusion, arrhythmia, heartblock and myocarditis (Hasdai, Berger and Battler, 2002, p.8). Other myopathic causes of cardiogenic shock are dilated cardiomyopathy, myocardial depression in septic shock, right ventricular failure, myocardial depression subsequent to cardiopulmonary arrest or bypass (Bates, 2002, p.24). Systolic dysfunction is a type of cause that can be related to myocardial contractility due to acute myocardial infarction or ischemia. The main triggers of cardiogenic shock in the said type are anterior MI, severe myocarditis, end-stage cardiomyopathy, myocardial contusion, and prolonged cardiopulmonary bypass. In patients with myocardial infarction as the main cause of cardiogenic shock, the left ventricular area of the heart is greatly damaged (Alonso, Scheidt, Post and Killip, 1973, p.594; (Sharma and Zevitz, 2008). Another type is the diastolic dysfunction which is associated to effects of different conditions of the heart such as cardiac ischemia and can be affected by hypovolemic shock, septic shock and systolic contractility depression. Valvular dysfunction can also be a myopic cause of cardiogenic shock or can lead to other aetiologies that can affect cardiac functions. Cases such as acute mitral regurgitation secondary to papillary muscle rupture or dysfunction can be classified as valvular in nature. Another case is mitral valve obstruction due to severely decreased cardiac output. Cardiac arrhythmias such as ventricular tachyarrhythmias, bradyarrhythmias, sinus tachycardia and atrial tacharrhythmias can immediately lead to cardiogenic shock or can contribute to hypoperfusion that can later lead to the condition. Coronary artery disease is also one of the most significant causes of cardiogenic shock especially in the older members of the population and those with diabetes and previous inferior infarction (Alonso, Scheidt, Post and Killip, 1973; Dzavik et al., 1998; Hasdai, Berger and Battler, 2002, p.9; Sharma and Zevitz, 2008). 2. Mechanical Failure Cardiogenic shock can also be associated with mechanical causes. Included in the said type of causes are acute mitral regurgitation, ventricular septal rupture, ventricular, free-wall rupture and ventricular aneurysm. Other probable mechanical causes of cardiogenic shock are left ventricular outflow tract obstruction such as aortic stenosis and hypertrophic cardiomyopathy; and left ventricular inflow tract obstruction such as mitral stenosis and left atrial myxoma. The said condition can also be caused by acute aortic regurgitation which is considered relatively as the most uncommon cause of cardiogenic shock (Bates, 2002, p.24). The cardiogenic shock then can be attributed to the effects of different conditions and defects related to the heart such as the myocardial functions, the integrity of the valves or cardiac structures. Defects in terms of these aspects can ultimately affect the hemodynamic and metabolic capacities of the cardiac structure and functions. For that matter, these defects that lead to cardiogenic shock can lead to more serious conditions (Hasdai, Berger and Battler, 2002, p.8). Upon the determination of the definition, aetiology, causes and state of state of cardiogenic shock, the treatment and management associated with the duties and role of the medical personnel are then determined and presented. Role of the Critical Care Nurses The cases of cardiogenic shock can be associated to serious emergency and medical treatment. For that matter, the roles of the medical professional, including the specialists, the physicians and the critical care nurses are essential to the welfare of the patient. The main focus of the study is the presentation of the role of the critical care nurses in relation to the management and treatment of cardiogenic shock and the conditions that are associated with it. Initial Clinical Evaluation Attention to the immediate needs of the patient for vital emergency procedures and diagnostic evaluation is crucial. The different forms of emergency conditions are commonly noted primarily including hypovolemic shock, obstructive shock and distributive shock which can occur in addition to cardiogenic shock. Nursing care plan is vital to the role of the critical care nurses. The primary step is assessment of the symptoms, specifically physical examination. History of cardiac conditions is determined through medical record. Being observant is important since the initial examination period is vital and assessment has no basis yet since clinical data are still being gathered (Elliot, Aitken and Chaboyer, 2006, p. 253). Different parameters should be undertaken. Continuous cardiac and arterial blood pressures are included in the role of the critical care nurses. Also, hourly urine output, hourly nasogastric output and hourly temperature monitoring are needed to be undertaken. Strict fluid balance and continuous central venous pressure are also needed to be monitored. Other essential parameters needed to be monitored continuously are respirations, arterial blood gas and blood sugar (Wilson-Ing, 2010). These processes will serve as basis for the determination of the status of the patient, e.g. if the patient already entered the compensatory stage, thus, additional procedures can be undertaken. Through the course of the treatment process, the different processes are undertaken such as haemodynamic management, respiratory and cardiovascular support, biochemical stabilization and reversal or correction of the cause of cardiogenic shock. The main role of the critical care nurses is the coordination in terms of management of the treatment procedures. Error in such duties can be detrimental to the health and safety of the patient (Elliot, Aitken and Chaboyer, 2006, p. 253; Urden, Stacy and Lough, 2009). Management and Treatment Process In the treatment process, different stages are undertaken. Management is crucial to the safety and recovery of the patient. Included in the medical management procedures undertaken specifically by critical care nurses are continuous monitoring of parameters in the initial assessment, administration of inotropes, administration of oxygen, initiation of intra-aortic balloon pump counterpulsation if recommended for the case, administration of diuretics and even GTN if needed, ad the continuous active warming of the patient (Elliot, Aitken and Chaboyer, 2006, p. 253; Unosawa et a., 2010; Wilson-Ing, 2010). Nursing care plan for respiratory conditions associated with cardiogenic shock includes dyspnoea, hypoxia, oxygen administration through facemask, ventilator and CPAP, and blood gas analysis. Cardiovascular management, on the other hand, includes rhythm for tachycardia, blood pressure monitoring, fluid management, temperature, clotting studies, and electrolytes. Neurological aspect of management of cardiogenic shock includes attention to altered level of consciousness, uraemic seizures, confusion and disorientation. Pain management is given to conditions related to ischaemic myocardium, ischaemic tissues, insertion of monitoring lines and the determination of level of consciousness. Management methods related to the nutrition and hydration of the patient is also essential. This includes strict fluid balance monitoring, variable blood sugar, paralytic ileus and increased nutritional requirements (Elliot, Aitken and Chaboyer, 2006, p. 253; Unosawa et a., 2010; Wilson-Ing, 2010). Management and treatment of the patient cover the processes from the initial assessment of the emergency condition to admission and to post-admission treatments as outpatient consultation. Issues Related to Treatment There are different issues in relation to the different levels of the treatment process of the cardiogenic shock. Due to the emergency status of the condition, immediate management is required. One of the issues related to the role of the critical care nurses is the clinical skills and capacity. Due to the importance of fact action and precise techniques, the mastery of skills is can be considered as one of the most important issues being faced in the treatment and management of cardiogenic shock. This is resolved through development of skills of the critical nursing personnel (Elliot, Aitken and Chaboyer, 2006, p. 33). Another important aspect is related to ethical issues in critical care. These issues revolve around the guidelines for taking care of the patients, which are specifically studied, thus, there are legal consequences when there are failures in executing such rules. The welfare of the patient is the primary priority of the critical care nurses. This is the common ethical question in cardiogenic shock treatment (p.88). Another controversial example is related to the rules on resuscitation (p.533). These are only some of the issues related to management of cardiogenic shock. As the technology improves, application of treatments can bring about more issues that are needed to be resolved such as the telecardiology monitoring which is presently being assessed for its feasibility (Nikus, Lahteenmaki, Lehto and Eskola, 2009). Analysis and Conclusion In the research undertaken related to cardiogenic shock and the role of critical care nurses, there are certain points presented. One is the need for immediate medical attention in the treatment of the condition. For that matter, the skills, capabilities and execution of the critical care nurses in the monitoring of vital parameters and treatment processes are the most important answer to the inevitability of the prevalence of the cardiogenic shock and its causes. References Alonso, D.R, Scheidt, S., Post, M. and Killip T. (1973). Pathophysiology of cardiogenic shock: quantification of myocardial necrosis, clinical, pathologic and electrocardiographic correlations. Circulation, 48(3), 588-96. Ang, C., Kornbluth, M., Thirlwell, M.P. and Rajan, R.D. (2010). Capecitabine-induced cardiotoxicity: case report and review of the literature. Current Oncology, 17 (1), 59-62. Baird, M.S., Keen, J.H. and Swearingen, P.L. (2005). Manual of Critical Care Nursing: Nursing Interventions and Collaborative Management. Elsevier Mosby. Bates, E.R. (2002). Cardiogenic Shock. NY: Wiley-Blackwell. Dzavik, V., Burton, J.R., Kee, C., et al. (1998). Changing practice patterns in the management of acute myocardial infarction complicated by cardiogenic shock: elderly compared with younger patients. Can J Cardiol., 14(7), 923-30. Elliot, D., Aitken, L. and Chaboyer, W. (2006). ACCN’s Critical Care Nursing. Australia: Elsevier. Hasdai, D., Berger, P.B. and Battler, A. (2002). Cardiogenic Shock: Diagnosis and Treatment. NJ: Humana Press. Hasdai, D., Holmes, D.R., Topol, E.J., et al. (1999). Frequency and clinical outcome of cardiogenic shock during acute myocardial infarction among patients receiving reteplase or alteplase: Results from GUSTO-III Global Use of Strategies to Open Occluded Coronary Arteries. Eur Heart J., 20(2), 128-35. Hermans, S.M. and Buys, E.M. (2010). Cardiogenic shock. Neth Heart J., 18 (7-8), 384. Hollenberg, S.M., Kavinsky, C.J. and Parillo, J.E. (1999). Cardiogenic shock. Ann Intern Med., 131, 47-59. Nikus, K., Lahteenmaki, J., Lehto, P. and Eskola, M. (2009). The role of continuous monitoring in a 24/7 telecardiology consultation service – a feasibility study. Journal of Electrocardiology, 42, 473-480. Sharma, S. and Zevitz, M.E. (2008, August 20). Cardiogenic Shock. Retrieved September 12, 2010, from http://emedicine.medscape.com/article/152191-treatment Unosawa, S., Hata, M., Sezai, A., Niino, T., Yoshitake, I., Shimura, K., Takamori, T., and Minami, K. (2010). Successful management of fulminant myocarditis with left ventricular assist device: report of a severe case. Ann Thorac Cardiovasc Surg, 16, 48-51. Urden, L.D., Stacy, K.M. and Lough, M.E. (2009). Critical Care Nursing: Diagnosis and Management. Mosby/Elsevier. Wilson-Ing, D. (2010). Cardiogenic and Septic Shock. Retrieved September 12, 2010, from http://www.nursingtheory.nhs.uk/PDF%20Files/Cardiac/Cardiogenic%20and%20Septic%20Shock%20Lecture.pdf Read More