Final Semester Project
chacol
draftprojectcharnel.docRunning Head: ANESTHESIA FOR PATIENTS WITH HYPERTENSION 1
ANESTHESIA FOR PATIENTS WITH HYPERTENSION 2
Anesthesia for patients with hypertension
Charnel N., Coleman
St. Petersburg College
Anesthesia for patients with hypertension
Essential hypertension has been found to be a common form of pathology that is observed in adult patients who undergo surgery. According to Le Manach et al. (2016), it was revealed through a study that up to 13% of sampled adult patients exhibited essential hypertension. Whereas, this study showed essential hypertension and an important clinical risk factor to adult patients undergoing surgery, the ACC/AHA guidelines provided in 2014 failed to consider its importance in surgery (Fleisher et al., 2014). This paper will discuss anesthesia for patients with hypertension.
Pathophysiology of hypertension
Pathophysiology of hypertension is a complex issue because it requires understanding of the vascular structure and functioning of the endothelial malfunction. Similarly, essential hypertension is created because of increased resistance from the vascular tissue and a high level of vasoreactivity (de Waal et al., 2015). The latter has severe consequences to blood pressure, and this should be considered by an anesthetist.
Vasoreactivity has been found to be higher in hypertensive patients than normotensive patients. This occurs because limited vascular tone differences cause a change to blood pressure of hypertension patients. As such, it causes an abrupt fall or rise in the blood pressure. Secondly, baroreflex resetting occurring in hypertension patients causes a shift in the flow of blood to important organs (European Society of Cardiology, 2014). In this regard, a decrease in blood pressure causes an equal reduction of blood flow to important organs of hypertension patients. Lastly, the left ventricle (LV) hypertrophy is specifically designed to tolerate high blood pressure.
Hypertension is a worst condition during surgery of hypertensive patients. Studies have shown that it is a form of dreadful triad that can cause endocardium ischemia without the patient having and problem of coronary complications. During surgery, anesthesia induces sympathetic stimulation and high blood pressure in hypertensive patients. For example, anxiety before onset of surgery, stress and hypoxia have been found to be common triggers of perioperative condition (de Waal et al., 2015). However, vascular and cardiac surgery cannot be controlled through cardiovascular regulation because tension to the vascular sutures will result to inducing bleeding.
Currently, hypertension is not considered as an important risk factor in predicting the amount of cardiovascular complications (Fleisher et al., 2014). According to Le Manach et al. (2016), hypertension is a dominant preoperative that does not occur in multivariate models that are used to determine death. Other epidemiology studies have shown that hypertensive patients suffer from post treatment management. Therefore, all hypertensive patients must be considered as being susceptible to hemodynamic instability following surgery using anesthesia. Where hypertension is not properly controlled, it acts as a major indirect risk factor that can result to coronaropathy.
Consequences of Anesthesia to Hypertensive Patients. General anesthesia has a major impact to sympathetic nervous system and renin-angiotensin system (Lee et al., 2015). For example, epidural anesthesia can lead to suppression of renin release as a positive response to development of arterial hypotension (Lee et al., 2015). Additionally, reduction of anesthesia to the sympathetic tone in the vascular capacitance causes a decrease of intravascular volume (Lee et al., 2015). This reduces the blood pressure during administration of anesthesia because the angiotensin II activity is suppressed by a competitive inhibitor (de Waal et al., 2015). On the other hand, endogenous vasopressin is directly involved in blood pressure control with the aid of receptors concerned with vasoconstriction (de Waal et al., 2015).
Secondly, blood pressure is created as a compromise from cardiac impact and systemic vascular tone (de Waal et al., 2015). As such, its regulation is influenced by the heart rate, stroke volume of the LV and its resistance. Anesthesia blunts the sympathetic nervous system (SNS), which has a major role in blood pressure regulation. Where the SNS has blocked, RAS is required to improve the situation after anesthesia has been administered (European Society of Cardiology, 2014). Therefore, anesthesia causes a decrease in blood pressure, which results from the activity of RAS blockade and antagonism from V1 receptors (European Society of Cardiology, 2014).
Anesthesia and Antihypertensive Drugs. The effects caused to the SNS results to administration of different management approaches. For example, propofol has a major impact to the level of vascular reactivity, which reduces the response of the vascular tissue to vasopressin. In hypertension patients, this level of antagonism is amplified (de Waal et al., 2015). Also, refractory hypotension has been linked to propofol effect in the body. Consequently, chronic treatment should be given during surgery.
Management of Hypertension Patients . It is important that the stage of hypertension should be determined by an anesthetist before surgery is undertaken. Patients treated with severe anti-hypertensive drugs can be considered to be at higher risk of developing hemodynamic uncertainty (Lee et al., 2015). Secondly, it is important to identify the damage caused to end-organs to form the basis of grading patients. Here, transthoracic echocardiography can be used evaluate LV hypertrophy to reduce risk of LV unpriming (European Society of Cardiology, 2014).
Titration can be used as a procedure for anesthesia induction where severe hypertension grade is established. Propofol affects vasoreactivity, which causes development of hypertension and reduced by slow induction (de Waal et al., 2015). Thirdly, blood pressure monitoring should be observed and complemented with intermittent measurements. Therefore, continuous measurements using arterial lines are an important consideration for emergency cases of surgery for patients with high hypertension.
As a management strategy, it is important to avoid any build-up of blood pressure in hypertension patients. This is important because it will reduce any chances of bleeding during the surgical process (de Waal et al., 2015). In the process of surgery, using anesthesia like sevoflurane initiates development of sympathetic blockade and this can reduce blood pressure. However, it is important to add antihypertensive diagnosis (de Waal et al., 2015). Similarly, it is important to control shivering because it is important to the titration process using drugs like nicardipine and esmolol.
Lastly, treatment of chronic hypertensive patients must be addressed as soon as possible, especially where it forms part of the multidrug regimen as a basis of preventing development of cardiovascular risks (Lee et al., 2015). In order to manage the perioperative period characterized by hemodynamic instability, beta-blocker can be utilized (Fleisher et al., 2014). Therefore, it is important for the doctor to resume treatment immediately with angiotensin receptors as a basis or reducing postoperative death of hypertension patients (European Society of Cardiology, 2014).
Conclusion . Hypertension remains an important concern for anesthetist before performing any surgery procedures. This is important because it forms the first etiology in the development of severe cardiovascular diseases for aged patients undergoing surgery. Secondly, HTA management has improved, but majority have failed to control hypertension during surgery. Therefore, a proper understanding of pathophysiology, little consideration of risk caused by antagonism of anesthesia and chronic treatment, security of drugs used and antihypertensive IV diagnosis of an important platform for anesthetist to prepare treatment and management of perioperative period.
References
European Society of Cardiology (2014). ESC/ESA Guidelines on non-cardiac surgery: cardiovascular assessment and management. European Heart Journal, 35(1): 2383-2431.
