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Learn about the pharmacokinetics, therapeutic uses, and administration of nitroglycerin for symptom relief in advanced paramedic skills. Understand its vasodilator, anti-anginal, and antihypertensive properties.
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Advanced Paramedic Skills Introduction to Symptom Relief II
Nitroglycerin • Vasodilator • Anti-anginal • Antihypertensive • Nitrate
What does NTG do?? Improvement in workload on the heartDilation of large coronary arteriesIncreased collateral blood flow to heartAntagonizes vasospasmLowers blood pressure with or without a subsequent rise in CODecrease in preload and systemic vascular resistance Decreases MvO2 and decreases left and right ventricular end-diastolic pressures (preload)
Pharmacokinetics • very substantial first pass metabolism in the liver • Intravenous nitroglycerin produces a slightly greater reduction in preload than SL nitro. • The HR only rises if the drop in preload causes the preload to be lower than the bodies needs. • tolerance to nitrates can develop in humans
Adverse Effects/Overdose • causes a headache due to dilation of vascular smooth muscle in the cerebral cortex • may cause transient but profound dizziness. • Reflect tachycardia • most serious adverse effect is hypotension • Nausea and or vomiting
Therapeutic Uses • Angina (stable or unstable) • Acute evolving MI • Congestive Heart Failure _Pulmonary Edema • Hypertension – • Coronary vasospasm (prinzmetals angina)
Supplied/Dose Sublingual Administration Supplied in 0.4 mg spray SR Dose is 0.4 mg SL q 5 minutes to max 6 Vital Sign Parameters must be met
Sublingual Administration Lab practise
Special PreHospital Concerns • light sensitive and a volatile molecule • IV is an imperative need for safe administration of the drug • drop in greater than 30 mmHg with the first dose of nitroglycerinstop administration
Standing Order • Indications: • Chest pain or discomfort consistent with cardiac ischemia • YOUR HISTORY AND ASSESSMENT is vital!!!
Conditions • To receive Nitroglycerin the patient must: • be alert and responsive • have used Nitroglycerin in the past (this includes Nitroglycerin spray, tablets, transdermal patch) • NOT have taken Viagra within the past 24 hours • have a systolic BP which is > 100 mmHg and a heart ratewhich is > 60 bpm and < 159 bpm
CHF • Standing Order for a certain subset of patients who are not nitrate sensitive • Presentation of severe or moderate SOB • Can reduce preload and help both ventilation and perfusion (V/Q) • Clinical picture of CHF
Causes of Congestive Heart Failure • Conditions that increase preload, e.g. aortic regurgitation, ventricular septal defects • Conditions that increase afterload, e.g. aortic stenosis, systemic hypertension • Conditions that decrease myocardial contractility, e.g. MI, cardiomyopathies, pericarditis, tamponade
S&S of Congestive Heart Failure • Exertional dyspnea - fatigue may be the first sign • Increased respiratory rate and effort • Orthopnea and/or PND • Cyanosis and pallor • Tachycardia • JVD • Dependant edema
Categorized • Left or Right sidedheart failure ???????????? • Forward or Backward ventricular failure • Backward failure is secondary to elevated systemic venous pressures. • Forward ventricular failure is secondary to left ventricle failure and reduced flow into the aorta and systemic circulation
NTG Administration for CHF INDICATIONS • Patient in moderate to severe respiratory distress. • Patient assessed by paramedic to be in acute pulmonary edema. CONDITIONS • Patient >18yr • Previous history of nitro use or IV • Systolic BP > 140 mmHg (2X) • Heart rate and/or pulse rate > 60 and <159bpm • No history of viagra use in the last 24 hours
1.Place patient in sitting position. 2.Administer 100% O2 as required. Support ventilation with BVM as necessary if reduced level of consciousness. 3.Attach cardiac monitor and continuous 02 sat monitoring if available. 4.Confirm that the systolic blood pressure is >140 mmHg and the patient has a history of previous nitroglycerin use. 5.Administer 0.4 mg nitroglycerin (1 spray sublingual) every 5 minutes if systolic blood pressure remains > 140. Check blood pressure before administering each dose of nitroglycerin. Discontinue nitroglycerin if BP drops below 140 systolic. Maximum number of nitroglycerin doses is six.
6.Reassess patient for additional Nitroglycerin administration. Administer NTG 0.4 mg spray SL every five minutes as needed for symptomatic dyspnea to a maximum of six doses. 7.Assess the BP and heart rate after each dose of Nitroglycerin administration. 8. Discontinue Nitroglycerin should the BP fall below 140 mmHg, or the heart rate drops below 60 bpm. 9. If either the systolic BP or heart rate falls outside of the listed conditions, no further Nitroglycerin will be administered for the remainder of the call.
ASA (Acethylsalicyclic Acid) • Anti-inflammatory • Platelet Aggregation inhibitor
Review of Events during Acute MI • Coronary artery blockage • platelet aggregation at site of blockage • reduced blood and oxygen flow to heart tissue • subsequent pain and/or failure of myocardial function
Platelet Activation • platelets in the blood respond to chemical signals that are present in the plasma (cause plts to activate or not) • prostacyclin is released from the endothelial cells • Another factor that prevents platelet aggregations is low circulating levels of thrombin and thromboxanes
Therapeutic Uses/Adverse Effects • Therapeutic Uses; anti-inflammatory anti-pyretic analgesic • Adverse Effects neurotoxic - confusion, lethargy, coma and death cardiovascular- acidosis, pulmonary edema, decreased ATP production, arrhythmia's
Special Prehospital Concerns • Contraindications; Allergic to ASA Allergic to NSAIDS Recent Head injury CVA in last 24 hrs current active bleed history of asthma Children + Asa = Reyes
Standing Order • Indications: • Chest pain or discomfort consistent with cardiac ischemia • Conditions • weigh at least 40 kg • be alert and responsive • NOT have an allergy to ASA or other NSAID • not have current active bleeding (GI or other disorders) • have no evidence of CVA or head injury within 24 hours • have a history of previous use of ASA with no adverse reaction if a known asthmatic