Case Scenario. Case Scenario

Transcription

1 1 Cse Scenrio Cse Scenrio Cse 7 Brdycrdi An 87-yer-old womn reports feeling wek nd short of breth for 2 hours while wlking short distnces. She feels exhusted moving from the cr to the ED stretcher. On physicl exm she is ple nd swety; HR = 35 bpm; BP = 90/60 mm Hg; RR = 18 rpm. Rhythm: see next slide Americn Hert Assocition Yer-Old Womn: Symptomtic Brdycrdi 87-Yer-Old Womn: Symptomtic Brdycrdi Lerning Objectives Identify A, B, nd C Which one is most likely A to be her rhythm? B C She experienced no chest pin or ischemic symptoms prior to the onset of her A wekness nd shortness of breth. Therefore, the only rhythm not ssocited with cute pin, rhythm A, is the more likely cuse of her symptomtic brdycrdi. 1. By the end of Cse 7 be ble to discuss Asymptomtic vs symptomtic brdycrdi Signs nd symptoms of symptomtic brdycrdi Intervention gents nd sequences to use Recognition criteri for hert blocks: 1 st, 2 nd (types I nd II), nd 3 rd degree Pthology of conduction system in hert blocks Lerning Objectives Wht is Symptomtic? Wht is Symptomtic? 2. By the end of Cse 7 be ble to discuss Significnce of brdycrdi in AMI ptients Significnce of RV infrction plus brdycrdi Atropine phrmcology: why tropine helps some hert blocks nd not others Set up, strt, troubleshoot trnscutneous pcing Brdycrdi is symptomtic when: Hert rte is slow (bsolute or reltive) Ptient hs symptoms Symptoms re cused by brdycrdi Symptoms Chest pin Dyspne Wekness Altered LOC 7 8 9

2 10 Wht is Symptomtic? Wht is Symptomtic? Wht is Symptomtic? Signs Hypotension Diphoresis Pulmonry congestion PVCs Unstble ngin Key question: Is the brdycrdi cusing the ptient to be ill? OR Is there some illness tht is cusing the brdycrdi? If the etiology is AMI: Tret the AMI (MONA) Wht is Symptomtic? Rhythms to Lern Drugs to Lern Key point: Tret the ptient nd NOT the monitor. Sinus brdycrdi Hert blocks 1 st degree 2 nd degree type I 2 nd degree type II 3 rd degree The ctions, indictions, dministrtion, nd precutions for these drugs nd therpies: Atropine Dopmine Epinephrine Trnscutneous pcing Isoproterenol (rrely used) Drugs to Lern Crdic Conduction System 1 Crdic Conduction System 2 Remember: Atropine will not work on denervted herts. Why? Epinephrine must be used with cution with some ptients. Why? Sinus node Internodl pthwys AV node Bundle of His Right bundle brnch Bchmnn s bundle Left bundle brnch Posterior division Anterior division Purkinje fibers Reltionship of ECG to ntomy

3 19 20 Determining the Rte Anlyzing Rhythm Strips Key questions Are QRS complexes present? Are P wves present? How is the P wve relted to the QRS complex? 21 Reltionship of P Wves nd QRS Complexes Wht Is This Rhythm? Every P wve is followed by QRS complex with norml P R intervl Every P wve is followed by QRS complex but the P R intervl is prolonged Some P wves re not followed by QRS complex; more P wves thn QRS complexes This is First Degree Block. First-degree AV block Dely Dignosis? Dignosis? Second-degree type I AV block This is Sinus Brdycrdi. This is Second-degree type I AV block. Note the progressive PRI

4 28 Dignosis? Differentition of Second- nd Third-Degree s Second-degree type II AV block More P s thn QRSs yes Non-Conducting P wves PR fixed? yes 2 nd -degree AV block Fixed Mobitz II no This is Second-degree type II AV block. Note the non-conducting Ps. QRSs tht look like regulr? no yes 3 rd -degree AV block 2 nd -degree AV block Vrible Mobitz I Wenckebch Brdycrdi Algorithm (1 of 2) Brdycrdi Algorithm (2 of 2) Brdycrdi Algorithm (2 of 2) Brdycrdi Slow (bsolute brdycrdi = rte <60 bpm) or Reltively slow (rte less thn expected reltive to underlying condition or cuse) Primry ABCD Survey Assess ABCs Secure irwy noninvsively Ensure monitor/defibrilltor is vilble Secondry ABCD Survey Assess secondry ABCs (invsive irwy mngement needed?) Oxygen IV ccess monitor fluids Vitl signs, pulse oximeter, monitor BP Obtin nd review 12-led ECG Obtin nd review portble chest x-ry Problem-focused history Problem-focused physicl exmintion Consider cuses (differentil dignoses) 31 For exmple: Serious signs or symptoms? Due to brdycrdi? 1 mg Epinephrine No or Isuprel in Yes 100 ccs NS 10 µgs / cc or 60 gtts / min 7.5 µgs = 45 gtts / min 5 µgs = 30 gtts / min No 2.5 µgs = 15 gtts / min Type II second-degree AV block or Third-degree AV block? Intervention sequence Atropine 0.5 to 1.0 mg Trnscutneous pcing if vilble Dopmine 5 to 20 µg/kg per minute Epinephrine 2 to 10 µg/min Isoproterenol 2 to 10 µg/min Yes Observe Prepre for trnsvenous pcer If symptoms develop, use trnscutneous pcemker until trnsvenous pcer plced 32 For exmple: OR you cn sy tht ech 6 gtts = 1 µg 33 Brdycrdi Algorithm (2 of 2) Wht Is This Rhythm? Remember tht Isoproterenol must only be considered if the ptient fils to respond to other therpies. You must exercise extreme cution when using it. Why? Third-degree AV block Consistent P to P intervl This is Third-degree AV block. Suprnodl note the tril rte is between

5 37 Wht Is This Rhythm? Tretment? Wht Is This Rhythm? Tretment? Indictions for Trnscutneous Pcing Indictions for Trnscutneous Pcing Hemodynmiclly unstble brdycrdis In the setting of AMI: sinus node dysfunction, type II 2 nd -degree block, 3 rd -degree hert block Brdycrdi with symptomtic ventriculr escpe bets In the presence of escpe bets, you must decide if the PVCs re effective contrctions Should they be treted with pcing or medictions (rte relted fix) Indictions for Trnscutneous Pcing Trnscutneous Pcing Trnscutneous Pcing: Cpture vs No Cpture However, 3 rd degree block should NEVER be treted with lidocine. Why? Brdycrdi: no pcing Pcing Spike Pcing below threshold: no cpture 25 Feb 88 Led I Size 1.0 HR=41 Brdycrdi: No Pcing 25 Feb 88 Led I Size 1.0 HR=43 35 ma Cpture: Spike + brod QRS QRS: opposite polrity Pcing bove threshold: with cpture Pcing Below Threshold (35 ma): No Cpture 25 Feb 88 Led I Size 1.0 HR=71 60 ma Pcing Above Threshold (60 ma): With Cpture (Pcing-PulseMrker ) 45

6 46 Rtes of Intrinsic Crdic Pcemkers Pulse Genertors for Trnsvenous Pcing Drug Clcultion Primry pcemker Sinus node ( bpm) Escpe pcemkers AV junction (40-60 bpm) Ventriculr (<40 bpm) Chrcteristics Vrible output in millimps Fixed versus demnd mode Vrible rte setting Firing nd sensing indictors Fmilirize yourself with the equipment! Dopmine Add 200 mgs into 250 cc bg of IV NS Ptient weight is 225 lbs. The initil dose would be gtts? Drug Clcultion Drug Clcultion Dopmine - effects Dopmine 200 mgs into 250 cc bg of IV NS 200 X 1000 µg = 200,000 µg OR 800 µg per cc OR µg per gtt Ptient weight is 225 lbs. The initil dose would be gtts? Dopmine So Ptient weight is 225 lbs. 225 / 2.2 lbs = 100 kgs 100 kgs X 5 µg/min = 500 µg/min 500 µg / = 37.5 gtts per minute lph hert:none rteries:constriction lungs:constriction bet hert: > rte rteries: diltion lungs: mild diltion Crdic dosge rnge is 5 µg - 10 µg/kg/min Infrct Loction Arrhythmis Escpe Ptterns RV Often present with incresed prsympthetic tone Look for volume problems with ssocited hypovolemi Determining the pttern Regulr Premture Speeding/slowing Puse Group bets Irregulrly Irregulr

7 55 Action Potentil of Pcemker Cell Second-Degree AV Block Type I 56