Pharmacology 2060A/B Lecture Notes - Lecture 13: Kidney Failure, Ace Inhibitor, Cardiac Output

• School: Western University
• Department: Pharmacology
• Course: Pharmacology 2060A/B
• Professor: Angela Nissen

Document Summary

The!patient!should!be!seated!for!at!least!5!minutes: no!caffeine!or!nicotine!within!30!minutes!of! measurement, feet!should!be!touching!the!floor!(not!dangling), arm!should!be!elevated!to!heart!level, two!measurements!in!each!arm!should!be!taken!5! minutes!apart, before!a!diagnosis!of!hypertension,!the!patient! should!have!this!repeated!3!times!at!least!2!weeks! apart. ! !blood!pressure: blood!pressure!is!classified!by!looking!at!the!systolic(and(diastolic!blood! pressure, systole! !when!the!heart! contracts, diastole! !period!of!time! when!the!heart!fills!after! a!contraction. Kidney!disease: hyperthyroidism, pregnancy, erythropoietin, pheochromocytoma! !tumour!on!the!adrenal!gland!that!causes!excess! epinephrine!release, sleep!apnea, contraceptive!use! 13. 2: we!now!know!that!blood!pressure!is!determined!by!cardiac!output!and! peripheral!resistance, there!are!three!systems!that!our!body!has!to!regulate!blood!pressure:, the!sympathetic!nervous!system, the!renincangiotensincaldosterone!system! (raas), renal!regulation!of!blood!pressure! Is!also!constantly!active!to!help!keep! body!functions! (including!blood! pressure)!in!homeostasis: the!sympathetic!nervous!system!has!a! reflex!circuit!called!the$ reflex!that!helps!keep!blood!pressure!at! a!set!level. !this!causes!decreased! cardiac!output!and!vasodilation: the!activity!of!baroreceptors!can!oppose!our! attempts!to!lower!bp!with!drugs!since!the! set! point !in!patients!with!hypertension!is!high. , the!baroreceptor!reflex!responds!rapidly! (seconds!or!minutes)!to!changes!in!blood!pressure, the!renincangiotensincaldosterone!system! (raas), the!renincangiotensincaldosterone!system! (raas)!is!comprised!of!a!series!of! protein!hormones, the!renincangiotensincaldosterone!system!plays!a!critical!role!in!regulating! blood!pressure,!blood!volume!and!electrolyte!balance, activation!of!the!raas!affects!the!kidney!and!vascular!smooth!muscle!to! control!blood!pressure, the!raas!is!a!target!for!many!blood!pressure!lowering!drugs, unlike!the!baroreceptor!reflex,!activation!of!the!raas!may!take!hours!or!days! to!influence!blood!pressure. !renin: catalyzes!the!formation!of!angiotensin!i!from! angiotensinogen, this!represents!the!rateclimiting!step!in! angiotensin!ii!formation. , renin!is!synthesized!and!secreted!by!the! juxtaglomerular!cells!of!the!kidney!into!the! blood, the!following!increase!renin!release:! Angiotensin!converting!enzyme! (ace): angiotensin!converting!enzyme! (ace)!converts!the!inactive! angiotensin!i!into!the!active! angiotensin!ii, activated!angiotensin!ii!is:, potent!vasoconstrictor!by! binding!to!its!receptor! (the! !aldosterone!acts!on! the!kidneys!to!increase! sodium!retention,!which!can! increase!water!retention: angiotensin!ii!also!acts!on!the! posterior!pituitary!gland!to!release! antidiuretic!hormone! (adh!also! called!vasopressin). !adh!causes!water!retention!by!the!kidney. ! Increased!blood!volume!causes!increased! cardiac!output!and!therefore!increased!blood! pressure. : noncpharmacological!interventions!are!the!initial!recommendation!for! patients!with!a!diastolic!blood!pressure!of!approximately!90! !95!mmhg, further,!noncpharmacological!treatments!augment!the!effectiveness!of!drug! therapy!in!patients!with!higher!blood!pressure, noncpharmacologic!interventions!include:! Decreasing!body!weight: restricting!sodium!intake, physical!exercise, potassium!supplementation, the!dash!diet, smoking!cessation, alcohol!restriction, decreasing!body!weight, there!is!a!direct!relationship!between!obesity!and!hypertension, obesity!is!thought!to!cause!hypertension!by!two!mechanism:! Obese!patients!have!increased!insulin! secretion,!which!causes!tubular! reabsorption!of!na+!and!therefore!water! reabsorption!and!a!higher!blood!volume: obese!patients!also!have!increased!activity! of!the!sympathetic!nervous!system, weight!loss!lowers!blood!pressure!in!up!to! 7: restricting!sodium!intake, salt!is!necessary!to!our!bodies,!however!when!sodium!chloride! (salt)!intake! is!too!high,!it!has!a!negative!effect!on!blood!pressure, the!kidney!regulates!the!amount!of!salt!in!our!body,!eliminating!excess!salt! in!the!urine. !, when!salt!levels!are!too!high,!it!causes!water!to!be!reabsorbed!from!the! kidney!into!the!blood, this!causes!increased!extracellular! (blood)!volume!and!therefore!increased! blood!pressure, limiting!salt!intake!to!5!g!per!day!decreases!systolic!bp!by!approximately!12! mmhg!and!diastolic!bp!by!6!mmhg, physical!exercise, regular!exercise!decreases!blood!pressure! by!an!average!of!10!mmhg. , regular!exercise!decreases!extracellular! fluid!volume!and!circulating!levels!of! plasma!catecholamines!(like!epinephrine). Just!as!total!body!sodium!levels!are!positively!correlated! with!blood!pressure,!total!body!potassium!levels!are! inversely!correlated!with!blood!pressure: this!means!high!total!body!potassium!results!in!lower!blood! pressure, high!potassium!diets!decrease!blood!pressure!by!increasing! sodium!excretion,!decreasing!renin!release!and!causing! vasodilation, preferred!sources!of!potassium!are!fresh!fruits!and! vegetables, **important**!patients!taking!ace!inhibitors!should! not(be!on!a!high!potassium!diet. !the!diet!also!excluded!foods!high! in!saturated!fat,!total!fat!and!cholesterol: the!results!were!remarkable!with!most!patients!achieving!lower!blood! pressure!within!14!days!without!lowering!salt!intake, the!best!results!were!seen!in!patients!with!prehypertension, patients!with!severe!hypertension!are!encouraged!to!stick!to!this!diet!in! combination!with!blood!pressure!lowering!medications.