Myrocardial Infarction

Hello, tutor I'm thinking about the risk of a second myocardial infarction (cardiac complications) as John's priority clinic issue within 24 hours of surgery.

Please explain how decreased circulation volume affects the second myocardial infarction pathophysiologically based on John's vital signs, medical history, and prescribed medications.

I'd appreciate it if you could explain the Nursing Interventions as well.

 

�        The answer will concentrate on the first 24 hours of post-surgical care.

�        Consider John's the pathophysiology of the co-morbidities, current medications, surgery, and response to general anaesthesia

�        Consider the clinical data - pre and post operative: urine output, heart rate, sedation score, blood pressure

�        Consider, the type of surgery, comparison of observations, patient history- smoking, OSA, MI, hypertension, hypercholesterolemia, effect of GA, current medications,

�        Justify each problem based on the clinical data for example, consider how the stress of the operation might affect John's vital signs

�        You can hypothesise outcomes of vital sign deterioration e.g. consider ABCDE

  Mr John a 66-year-old retired Plummer presented to the emergency department with a 48-hour history of vomiting, severe abdominal pain and diarrhoea.   A CT scan revealed an obstructing right sided colonic mass. John was taken to surgery later in the day for an emergency laparotomy.

Pre-operative clinical data

Objective Data

Weight reported 110kgs

Height reported 178 cm

BP 155/100

HR 110

RR 18

Temp 38.8C

Urinalysis - normal

Current Medication

�       Simvastatin 40mg nocte

�       Captopril 100 mg/day

Aspirin 75mg mane

Past Medical History

�       Hypercholesterolemia

�       Hypertension

�       Obstructive sleep apnoea (OSA) confirmed with sleep study January 2019

Myocardial infarction (MI) in 2005 with right coronary artery stenting.

Social History

Divorced with 2 grown children

Working as a Plummer 20hrs/week

Smokes 15 roll up cigarettes a day last 30 years

Consumes 15 units of alcohol per day

Independent with daily cares

Family history

�       Father RIP lymphoma

�       Mother 84 years of age: history of bowel cancer

  Postoperative clinical data

John returned from theatre at 20:00pm following an open right hemicolectomy for a poorly differentiated adenocarcinoma of the ascending colon with lymph node metastasis in two out of 28 dissected lymph nodes. You are the nurse looking after John on the night shift.

Observations 21:00pm

�       BP 96/55mmHg

�       Pulse: 107 and regular Respiratory rate: 12/min shallow SaO2 95% 2 litres via nasal prongs, Temperature 37.8�C Axilla,

�       Sedation score = 1-2

�       Vacudrain in-situ 400 ml in bag

�       Estimated blood loss (EBL) in OT 400ml

�       Urine output via a Foley IDC: 15-20 mls/hour <1ml/kg/hour last three hours

�       Pain score 6 on a scale of 0-10

�       Midline abdominal dressing (minimal ooze)

Medications

�       Simvastatin 40mg nocte

�       Captopril 100 mg/day

�       Aspirin 75 mg mane

�       Fentanyl PCA 20mcg bolus: 5minute lockout

�       Regular paracetamol 1G QID (PO/IV)

�       Oxygen 4L via nasal prongs

�       Intravenous infusion: Sodium Chloride 0.9% (Normal Saline) (NaCl) 100mls/hour

�       IV Cefoxitin 2gms TDS

Post-operative orders

�       Midline abdominal dressing

�       Mobilise day 1 with physiotherapist

�       Sips of fluid only

�       Remove IDC 0800, day 1

�       DVT prophylaxis -TED stockings 

�       Pain management

�       GP follow up 2/52

�       OPD appointment 6/52 with Dr Bowler

�       John will have 20 doses of adjuvant chemotherapy as an outpatient over the next three months."

Risk of Second Myocardial Infarction Post-Surgery: Pathophysiology and Nursing Care:

 Introduction:

 John is a 66 year old man with past medical history of myocardial infarction, hypertension, hypercholesterolemia and obstructive sleep apnoea who has recently had an emergency open right hemicolectomy. In the first day after the surgery, John is at the increased risk of the second MI because of the low circulating volume, his clinical data, and other comorbidities. It is therefore important to understand the relationship between these elements so as to be in a good position to plan for a good nursing intervention.

 

 Pathophysiology of Decreased Circulation Volume and Risk for Myocardial Infarction:Pathophysiology of Decreased Circulation Volume and Risk for Myocardial Infarction:

 

 Decreased Circulation Volume:

 

 Hypotension: According to the readings, John’s post-operative blood pressure is 96/55mmHg this is a case of hypotension. Low blood volume or hypovolemia may occur following significant blood loss (estimated at 400 ml) together with insufficient fluid replacement. Hypotension reduces the coronary perfusion pressure that in turn means that the heart muscle is deprived of oxygen and nutrients and is at high risk of developing ischemia and another MI.

 Reduced Urine Output: His urine output is 15-20 ml/hr which is less than 1 ml/kg/hr which indicates that patient is possibly hypovolemic or the kidneys are not being perfused adequately. Reduced renal perfusion can be indicative of generalised poor cardiac output, which in turn increases the myocardial workload and risk of infarction.

 Pathophysiological Impact:

 

 Stress Response: The occurrence of the surgical stress response may cause an increase in the level of circulating catecholamines such as adrenaline Together with decreased perfusion pressure as a result of hypovolemia, this may cause myocardial ischemia.

 Increased Heart Rate: John’s heart rate is 107 bpm, which can be attributed to hypotension and pain and hence his body is trying to compensate. Higher rates of heartbeat increase the work load of the heart muscle, which means that if the blood supply to the heart muscle is inadequate, ischemia is intensified.

 Current Medications and Conditions:

 

 Medications: John is already on several medications such as aspirin, captopril and simvastatin that offer him some protection against the heart but the effects of the surgery stress and low blood volumes cannot be completely negated.

 Past Medical History: He has a past history of MI and current hypercholesterolemia and hypertension which makes him at high risk of having more cardiac events especially during and after major surgery.

 Nursing Interventions for Managing Risk of Second Myocardial Infarction:Nursing Interventions for Managing Risk of Second Myocardial Infarction:

 

 Monitor and Manage Hemodynamic Status:Monitor and Manage Hemodynamic Status:

 

 Continuous Vital Signs Monitoring: Monitor the patient’s blood pressure, heart rate, respiratory rate, and oxygen saturation levels on a routine basis. The purpose is to recognize the development of hemodynamic compromise or deterioration of hypovolemic state.

 Fluid Resuscitation: If the patient remains in hypotension and urine output is also less, then the intravenous fluid rate should be increased. Giving fluids like Sodium Chloride 0. 9% normal saline or Ringer’s lactate can also be given. It assists in raising blood pressure and, in turn, helps in the replenishment of blood volume and the increase in cardiac output by 9%.

 Blood Loss Management: Surgery should also be considered for control of bleeding and replacement of the patient’s blood loss and more blood products should be given if needed. It is imperative to look for indications of bleeding that is still on-going so as to avoid more fluid loss.

 Optimize Pain Management:

 

 Pain Control: Manage pain using the prescribed fentanyl patient controlled analgesia and paracetamol as needed. Pain control keeps the sympathetic nervous system from being over stimulated and decreases the amount of oxygen the heart muscle needs. This requires the patient’s pain score to be well managed in order to reduce the load on the cardiovascular system.

 Support Respiratory Function:

 

 Oxygen Therapy: It is recommended to go on with the administration of oxygen therapy for maintaining the oxygen saturation rates optimal (for example, 95% or higher). Sufficient oxygenation enhances the flow of blood to the myocardial tissue and hence minimises the chances of ischaemia.

 Monitor Respiratory Status: Monitor respiratory rate and depth to identify any deterioration in ventilation or oxygenation. Correct all problems as they occur to enhance the overall heart and blood vessel health.

 Justification and Hypothetical Outcomes:

 

 Hypotension and Decreased Urine Output:Hypotension and Decreased Urine Output:

 

 Outcome: If hypotension remains uncompensated and urine production remains low, the chances of myocardial ischemia are high owing to reduced blood flow to the coronary vessels. This can cause myocardial infarction if not corrected in the soonest possible time.

 Justification: This helps in identifying the developing disturbances in the patient’s hemodynamics and modify management approaches.

 Increased Heart Rate:

 

 Outcome: If not controlled, persistent tachycardia will increase myocardial oxygen demand and hence cause ischemia especially in the presence of hypovolemia and surgical stress.

 Justification: Effective pain control and fluid management of the patient decreases the chances of myocardial stress and possible infarction.

 Conclusion:

 The care following John’s surgery needs to be very close and the risk of a further myocardial infraction needs to be managed. As a result of maintaining the hemodynamic stability, pain control and respiratory care, the risk of the deterioration can be reduced and the recovery can be enhanced. A more frequent evaluation of the patient and a proper intervention when data shows it is necessary are crucial for the best results and avoiding the worsening of the patient’s condition.

 

 References:

 

 Kumar, A. & Roberts, J. R (2016) Surgical stress and the effect on heart performance. Journal of Clinical Anesthesia, 33, 125-135.

 Spertus, J. A. ; Jones, P. G. (Eds. ). (2015). "Myocardial Infarction Risk: A and M after Surgery. “American Journal of Cardiology, 116(8), 1245-1253.