Critical Discussion Paper – Pharmacokinetics And Nursing Management

Introduction to Nursing Management

Nursing management comprises of the performance of different leadership functions that are related to decision making within healthcare organisations and governance (Kitson, Marshall, Bassett & Zeitz, 2013). The case study is about a patient Mr. Ferguson, a 76 year old individual who has been admitted to the Emergency department, following complaints of chest heaviness. The patient also demonstrated diaphoresis, and shortness of breath. Some of the other abnormalities in the patient’s health are hypertension and tachycardia.

The medications that were administered to the patient include aspirin, metoprolol, rosuvastatin and glyceryltrinitrate pump spray. This assignment will discuss in details the pathophysiology of the patient’s condition and will also elaborate on the pharmacokinetics of the prescribed medications.

Pathophysiology

Tachycardia common referred to as tachyarrhythmia refers to the physiological condition when the heart rate of a person exceeds the normal resting heart rate. Usually, heart rate higher than 100 beats per minute is regarded as an indicator of tachycardia. In the words of Al-Zaiti and Magdic (2016) at the cellular level, higher heart rate is often associated with abnormal automacity and/or electrical re-entry. Myocardial scarring often occurs as a manifestation of any physiological processes and usually increases the probability of electrical reentrant circuits.

There is mounting evidence for these circuits to comprise of a region where standard electrical propagation gets decelerated by the presence of scar (Gupta & Figueredo, 2014). Previous history of Mr. Ferguson states that he had a past medical history of angina, hypercholesterolemia, hypertension, and Non-ST Elevated Myocardial Infarction (NSTEMI). Owing to the fact that the cardiac output gets reduced as a direct consequence of reduced ventricular filling from increased heart rate and absence of appropriately timed atrial contraction (Sasaki et al., 2015).

Furthermore, the patient was also found to suffer from hypertension. This condition refers to high blood pressure and is a medical condition characterised by sudden elevation in the pressure of blood, flowing in the arteries. The fact that Mr. Ferguson suffered from an elevated blood pressure can be accredited to the structural narrowing of the small arterioles and arteries, besides a reduction in the density and number of capillaries (Mollan et al., 2016).

Shortness of breath was another presenting complaint reported by the patient. Dyspnoea refers to a situation when a person is not able to breathe enough. Hence, the condition manifested by Mr. Ferguson could be defined as a subjective experience of discomfort in breathing that encompasses qualitatively separate feelings that differ in intensity. According to Anzueto and Miravitlles (2017) three major mechanisms are thought to contribute to dyspnoea namely, efferent signals, afferent signals, and central information processing.

The central processing present in the brain associates the efferent and afferent signals, and usually occurs when there is a “mismatch” between the signals. In addition, the fact that the patient also suffered from angina acts as a major risk factor to the onset of chronic conditions (Coccia, Palkowski, Schweitzer, Motsohi & Ntusi, 2016). This pressure in chest occurs due to presence of an imbalance between the demand and supply of oxygen in the heart.

Pathophysiology of the Patient’s Condition

Pharmacokinetics

Aspirin refers to the medication that is used for treating fever, pain and inflammation. Aspirin is quickly absorbed through the cell membrane, under conditions that are acidic inside the stomach. Greater surface area of the small intestine and an elevated pH results in aspirin to get absorbed in a slow manner, while the rest of it gets ionized (Vane, 2014). The acetyl group is found to covalently attach to a residue of serine near the active site of the COX enzyme, thus producing an inhibitory impact on aggregation of platelets. This antithrombotic property of aspirin helps in reducing heart attack, in people who have had suffered from angina or TIA. 300mg of Aspirin is the standard dosage for adults and are taken orally.

Morphine is a pain medication that belongs to the opiate family, and directly acts on the central nervous system for reducing sensations of pain. This drug is frequently administered for pain management during myocardial infarction. Morphine is usually taken orally, sublingually, subcutaneously, intravenously or epidurally.  The drug is primarily metabolized into Morphine 6 gluconoride (M6G) and Morphine 3 gluconoride (M3G) through the process of glucoronidation (Tzvetkov et al., 2013). The action of the drug on the receptors present in CNS helps in relieving analgesia and pain. The dosage for adults should be 5-15 mg for 30 minutes, and 2.5-5.0mg every hour later.

According to De Caterina et al. (2013) heparin sulphate refers to an anticoagulant that is specifically used for preventing pulmonary embolism, deep vein thrombosis, and arterial thromboembolism. It is also used for the treatment of unstable angina and heart attack. This drug binds to antithrombin III (AT), the enzyme inhibitor and results in a conformational change, which leads to its activation via an elevation in the reactive loop flexibility (Mendell et al., 2013).

Activated AT results in activation of factor Xa, thrombin and other protease. A ternary complex is formed in between thrombin, AT, and heparin, thus leading to thrombin inacivation. Fentanyl helps in providing effects that are typical of other kind of opioid drugs via activation of different types of opioid receptors. High lipophilicity can be cited as a reason for its strong potency, in comparison to morphine that helps it to easily penetrate the central nervous system (Barratt et al., 2014). 20–50mcg/kg is considered as a moderate dose for administration of fentanyl via intravenous route.

Nursing management

Apart from the prescribed medications, beta blockers class of medications must be administered to the patient to manage the abnormality is in heart rhythm and to protect him from a second myocardial infarction. Beta blockers are competitive antagonists that are found to block the receptor sites, specific for endogenous catecholamine like epinephrine and norepinephrine, and have been found effective for treatment of primary hypertension and preventing stroke (Andersson et al., 2014). In addition to their activity in the heart they will also influence renin angiotensin system, and result in a decrease in secretion of renin, which in turn will lower the oxygen demand of the heart by lessening extracellular volume, and elevating oxygen carrying capacity of the circulating blood.

Pharmacokinetics of Prescribed Medications

Evidences have shown that heart failure characteristically encompasses an elevated activity of catecholamine on the heart that is responsible for several deleterious impacts like greater oxygen demand, abnormal remodelling of cardiac tissue, and transmission of inflammatory mediators (Raphael et al., 2015). The drug will result in enhanced ejection fraction and proper heart rate.

Verapamil medication will also prove useful in treatment of angina, tachycardia, and high blood pressure. This drug will block the voltage dependent calcium channels by acting as a class-IV antiarrhythmic agent. Owing to the prevalence of calcium channels in the atrioventricular node send sinoatrial node, this drug will reduce conduction of impulse through the AV node, thereby protecting the ventricles from tachyarrhythmias (Tarkin & Kaski, 2013). Nursing management will also encompass performing an accurate assessment of the patient via the ‘PQRST’ pain assessment where the position or provotic factors, quality of pain, radiation, severity of symptoms, and time would be taken into consideration (MacSorley et al., 2014).

Administration of coronary vasodilator would be another essential nursing step where glyceryl trinitrate will be administered intravenously and will act on the smooth vascular muscles, thereby exerting a vasodilator impact on the arteries and the veins, thus reducing intracellular levels of calcium, and causing vasodilation. Documenting the vital signs, performing a 12-lead ECG, and maintaining proper access to a defibrillator is essential. Some physical therapy techniques for the patient should include volume augmentation by breath stacking, active assisted cough techniques, and education about ventilation patterns, body position, and movement strategies for facilitating easy breathing (Moss et al., 2016).

Educate patient and clinical consideration

Efforts will be taken to educate Mr. Ferguson and his family members on the contraindications and adverse effects that the prescribed medications might exert on his health.  Some of the adverse effects of aspirin can be associated with mild diabetes, peptic ulcer, increased risk for stomach bleeding, gastrointestinal bleeding, gastric mucosal erosion, and temporary tinnitus in the ears (Baron et al., 2013). Other long term impacts can also include Reye’s syndrome, characterized by fatty liver and encephalopathy, and allergic reaction in the skin due to salicylate intolerance. Long term adverse effects of the opioid morphine would also be discussed with the patient. Some of these effects might be dizziness, opioid dependence, loss of appetite, immunodeficiency, depression, increased risk of falls, slowed breathing and abnormal paint sensitivity that is opioid induced (Zeppetella & Davies, 2013).

The patient will also be educated on the serious adverse effects of heparin administration that is heparin induced thrombocytopenia (HIT) (Keyl, Zimmer, Bek, Wiessner & Trenk, 2016). This might result in and immunological reaction, which would target the platelets and lead to the degradation. Overdose of fentanyl might also lead to constipation, nausea, sweating, confusion, and somnolence (Kuip, Zandvliet, Koolen, Mathijssen & van der Rijt, 2017). Low dose of Aspirin should be taken by the mouth, followed by swallowing them whole in order to prevent stomach ailments. The medication must be immediately discontinued if allergic reactions are observed.

Changes in behaviour with vomiting and nausea would indicate early signs of Reye’s syndrome. Overdose of fentanyl must also be prevented to avert unexpected respiratory depression. Overdose treatment of morphine or its combined administration with other opioids would result in death and asphyxia by respiratory depression. Hence, the drug must be administered in low doses.

Nursing Management – Beta Blockers and Verapamil Medications

Conclusion

To conclude, the patient Mr. Ferguson is suffering from several chronic conditions such as, hypertension, dyspnoea, and tachycardia, all of which might prove life threatening, if not managed and treated appropriately. Efforts must be taken to consider his past medical history and administer medications to prevent any contraindications, or adverse effects on his health. Educating the patient and his family on the adverse effects that the prescribed drugs might exert is also essential for his enhanced health outcomes.

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