Pacemakers & Atropine

8/18/2019 Pacemakers & Atropine

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7. Mechanical and Electrical Capture

When the hearts intrinsic pacemaker fails, an electronic device called a pacemaker is used to initiateelectrical impulses. A pacemaker is a device that uses electrical stimulus via a lead wire system to theheart muscle to cause depolarization of the myocardium. There are two main types of articialpacemakers, permanent and temporary. In the ED, nurses will work with temporary non invasive

pacemakers in emerent situations, as they can !e rapidly initiated to sta!ilize the patient"s rhythmand allow time to plan further care.

Transcutaneous Pacing

When the electrical conduction of the heart is a!normal, transcutaneous pacin #T$%& can !eused to temporarily restore electrical activity of the heart #$rai, '(()&. *ther names for T$% includenon+invasive cardiac pacin, eternal cardiac pacin, precordial cardiac pacin, temporary pacin andeternal transthoracic pacin #%roehl, '((-&.

Indications for T$% include the followin cardiac arrhythmiaso /or symptomatic !radycardias unresponsive to pharmacoloic therapy0o /or symptomatic second and third deree heart !lock.

#1iha, '(22&.$ontraindications for performin T$% areo 3isinterpretin a ne ventricular !rillation as asystole may lead to pacin when

de!rillation is neededo 4evere hypothermia !ecause the !radycardia may !e physioloical result of a decreased

meta!olic rateo %roloned !radyasystolic cardiac arrest #5'( min& !ecause the chance of success is low

#%roehl, '((-&.

It is important to prepare the patient prior to the procedure !y eplainin the purpose of T$% andwhat can !e epected. Eplain that it will involve some discomfort, and that you will !e administerinmedication to provide comfort and help to rela. 6et place the patient into supine position andepose the chest. $lip ecessive !ody hair instead of shavin as shavin may create tiny nicks in theskin, causin pain and irritation. %osition the electrodes. %rovide sedative. /ollow the steps outlined !yyour health authority.

#$rai, '(()&.

Pacing

When preparin to pace, a machine #such as the lifpak 2' in 1iha& is connected to theelectrodes located on the patient"s chest. The pacin rate is usually !etween )(+2(( !eats per minute.An output #mA& is set to zero and the machine is turned on. As the current is increased with muscles ofthe chest wall will contract with each impulse and a pacin spike will appear on the E$7.

In 1iha the ED nurse will follow the steps outlined in the policy8 procedure in Appendi A, included asattachment to this post.


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#Del3onte,'((-&

After achievin an electrical capture with the pacemaker, always check for a pulse. A palpa!lepulse conrms the presence of a mechanical response of the heart to the paced 9:4 comple #ie.$ontraction of the myocardium&. ;oth mechanical and electrical capture must occur to !enet thepatient.

11. Atropine in ACLS

Mechanical Capture Electrical Capture

• 3echanical capture is myocardial

contraction and is evidenced !y apulse and sins of improved cardiacoutput. 4ins of improved cardiacoutput include a palpa!le pulse, rise in!lood pressure, improved level ofconsciousness, improved skin colorand temperature.

• Assess the patient for mechanical

capture !y palpatin a pulse. ADoppler, a pulse oimeter or !oth may!e useful in assistin to identify andconrm the mechanical capture.

• Document a mechanical capture with

vital sins.

• Electrical capture occurs when a pacin

stimulus leads to depolartization of theventricles and is conrmed !y E$7chanes displayed on the monitor.

• The capture threshold is determined !y

turnin on the pacin machine. ;einninat zero milliampules #mA&, increase theoutput until the electrical capture is seen

• Electrical capture is evidenced !y a wide

9:4 comple #5(.2' msec& and a !road Twave followin the pacin artifact. Thismeans that the pacin

• $apture threshold usually ranes from a!ove the threshold.• ?ypoia, acidosis, pericardial e@usion, and

tamponade may lead to hiher thresholds

• The identication of electrical capture

may !e dicult in the presence of E$7sinal distortion. %ositionin the E$7 leadsas far away as possi!le from the pacinleads can minimize the distortion.

• Document the mechanical capture with a

rhythm strip indicatin the pacemakersettins.


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ATROPINEAnticholinergic drugse!

• /irst dru used to treat !radycardia inthe !radycardia A$B4 alorithm.

E"ect!

• Increases the rin of the 4A 6ode !y!lockin the action of the vaus nerveon the heart resultin in increasedheartrate.

Cautions!

• 4hould !e used cautiously in thepresence of myocardial ischemia andhypoia since it increases oyendemand of heart and can worsenischemia.

#osage!

• 3aimum (.(

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