Transcript Intraoperative ECG Lead Placement - Oregon

Intraoperative ECG Lead Placement
Brian Matthews SRNA
Nicholas Stoddard SRNA
David Perkins SRNA
Monitoring Basics
• Impulse toward positive
is an up swing; away
from positive is down.
• J point, or “junction
point”, is located at
junction of S wave and
start of ST segment.
• ST segment is
Measured 60
milliseconds from
the J point.
• 1mm change from
baseline suggests
myocardial injury.
Leads Bipolar and Augmented Placement
(Frontal plane)
• Bipolar leads read from
negative to positive.
• Bipolar leads are Lead
I, II, and III also referred
to as the limb leads.
• Augmented leads read
from center to specific +
lead and are unipolar.
• Augmented leads are
aVR, aVL, and aVF.
Precordial Lead placement
(Horizontal plane)
• Unipolar leads, reading from
center to outward.
• V1: right sternal boarder
4th intercostal space
V2: left sternal border 4th
intercostal space
V3: halfway between V2
and V4
V4: left 5th intercostal
space, mid-clavicular line
V5: horizontal to V4,
anterior axillary line
V6: horizontal to V5, midaxillary line
Which lead(s) is/are best?
Incidence/Indications
• “The pooled results
from the studies
evaluating patients
who had or were at
risk of cardiac disease
suggest that 3.9%
(95% CI 3.3%–4.6%)
of these patients
experience major
perioperative cardiac
events.”
Cardiac Events in Noncardiac Surgery
London et al 1988
• n-105 with CAD
• Single lead
monitoring
unacceptable low
• Leads II and V5 had
80% sensitivity
• Leads II, V4, and V5
had a sensitivity of
96% for detecting
ischemic events
Landesberg et al 2002
• n-185 major vascular
surgery
• Continual 12 lead
monitoring during surgery
• “We conclude that as a
single lead, V4 discloses
ischemia earlier, more
frequently, and with a
greater relative ST
depression than the
conventional V5”
• Two lead monitoring is
required to approach 95%
sensitivity.
Martinez et al 2003
• n-149 Post-op ICU
• “The majority of
ischemia occurred in
leads V2, V3, and
V4, suggesting that
the routine practice
of monitoring leads
II and V5 may not
be optimal.”
Martinez et al 2003
• “Given that in routine ICU
care leads II and V5 are
usually monitored, we
estimated that if all
ischemic episodes
occurring in either or both
of these leads were
detected, the maximal
possible sensitivity of
standard monitoring is
41% for detecting the first
episode of ECG evidence
suggestive of prolonged
Ischemia”
12-lead “Fingerprinting”
“First and foremost, if a preoperative 12-lead ECG has been done,
“fingerprinting” of the tracing should serve as the primary guide
for lead selection during the perioperaive period. If the baseline
12-lead shows significant primary ST-segment changes in leads
V3,V4 and V5, then this lead set should be prioritized for
continuous display in the operating room.” (Nagelhout, & Plaus,
2010)
“A preoperative resting 12-lead ECG is recommended for patients
with at least one clinical risk factor who are undergoing vascular
surgical procedures and for patients with known CAD, peripheral
arterial disease, or cerebrovascular disease who are undergoing
intermediate-risk surgical procedures. A perioperative ECG is
reasonable in persons with no clinical risk factors who are about
to undergo vascular surgical procedures and may be reasonable
in patients with at least one clinical risk factor who are
undergoing intermediate-risk operative procedures” (Barash, et
al. 2009)
Recommendations
• If no pre-op 12 lead: then monitor Leads II and
V3/V4.
• With pre-op 12 lead available and normal; then
the electrocardiographic lead with the most
isoelectric ST level out of leads V3, V4, and V5
on the preoperative electrocardiogram is
recommended or monitoring of ischemia.
• If 12 lead available with ST changes,
“fingerprinting”, monitor those specific leads.
Works Cited
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Barash, P, Bruce, C, Robert, S, Cahalan, M, & Stock, M. (2009).
Clinical anesthesia. Philidelphia: Lippincott Williams & Wilkins.
Devereaux, P, Goldman, L, Yusurf, S, Gilbert, K, & Leslie, K. et al
(2005). Surveillance and prevention of major perioperative ischemic
cardiac events in patients undergoing noncardiac surgery: a review.
JMAC, 173(7), 779-788.
Landesberg, G, Mosseri, M, Wolf, Y, Vesselov, Y, & Weissman, C.
(2002). Perioperative myocardial ishecmia and infarction.
Anesthesiology, 96, 264-270.
London, M, Hollenberg, M, Wong, M, Levenson, L, & Tubau, J.
et.al.(1988). Intraoperative myocardial ishemia: localization by
continuous 12-lead electrocardiography. Anesthesiology, 69, 232-241.
Martinez, E, Kim, L, Faraday, N, Rosenfeld, B, & Bass, E. (2003).
Sensitivity of routine intensive care unit surveillance for detecting
myocardial ischemia. Critical care medicine, 31(9), 2302-2308.
Nagelhout, J, & Plaus, K. (2009). Nurse anesthesia. St. Louis, Missouri:
W B Saunders Co.