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Anesthesia Cases

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Title: Anesthesia Cases


1
Anesthesia Cases
2
The Case
  • A 68-year-old woman with multiple cardiac risk
    factors had sudden onset of crushing substernal
    chest pain.
  • Despite aggressive thrombolytic therapy, the
    patient had electrocardiogram (ECG) evidence of a
    transmural anterolateral myocardial infarction
    (MI).
  • Three weeks following the MI, the patient
    develops acute cholecystitis, and presents for a
    cholecystectomy.

3
QUESTIONS
  • 1.How do you evaluate the cardiac risk in a
    patient scheduled for noncardiac surgery?
  • 2.What is the cardiac risk in this patient? What
    additional investigations should be performed?
  • 3.What are the implications for anesthetic
    management when coronary revascularization is
    performed before noncardiac surgery?

4
QUESTIONS
  • 4.What intraoperative monitors would you use?
  • 5.What additional drugs would you have prepared?
  • 6.What anesthetic technique would you use?
  • 7.How would you manage this patient
    postoperatively?

5
How do you evaluate the cardiac risk in a
patient scheduled for noncardiac surgery?
6
Preoperative Cardiac Evaluation
  • The cornerstone of preoperative cardiac
    evaluation includes
  • Review of history
  • Physical examination
  • Diagnostic tests
  • Knowledge of the planned surgical procedure.

7
Preoperative Cardiac Evaluation
  • Is readily available, inexpensive, easy to
    perform and able to interpret and detect previous
    myocardial infarction, acute ischaemia, or
    arrhythmias.
  • The presence of abnormalities such as Q waves and
    non sinus rhythms has been shown to correlate
    with adverse postoperative cardiac events.

Preoperative Resting Electrocardiogram
8
Stepwise approach to preoperative cardiac
assessment
9
What is the cardiac risk in this patient? What
additional investigations should be performed?
10
Perioperative cardiac risk
  • Pt factors major risk (recent MI)
  • Surgical factors major intraperitoneal surgery
    is an intermediate risk.

11
Additional Tests
  • Stress tests
  • Exercise stress test
  • Pharmacological
  • Dobutamine stress echocardiography.
  • Dipyridamole thallium scintigraphy.

12
Additional Tests
  • Preoperative coronary angiogram / coronary
    intervention
  • The decision for or against preoperative
    angiogram, coronary revascularization,
    percutaneous interventions (PCI) or coronary
    artery bypass grafting (CABG), should be based
    entirely on universally accepted medical
    indications for coronary revascularization and
    the appropriate technique.

13
Coronary angiography in this case is class (I)
According to ACC/AHA guidelines for PCI after
thrombolysis, as formation of Q waves in ECG
after thrombolysis is considered an evidence of
ischemia.
14
  • What are the implications for anesthetic
    management when coronary revascularization is
    performed before noncardiac surgery?

15
Anesthetic implications of revascularization
  • Prophylactic coronary revascularization in
    patients with asymptomatic CAD before major
    surgery has no benefit.
  • Revascularization by CABG or PCI must be
    justified according to long term outcome.
  • PCI- angioplasty is now often accompanied by
    stenting which require post procedure
    antiplatelet therapy to prevent acute coronary
    thrombosis.

16
Recommendations for timing of non-cardiac surgery
after PCI. PCI percutaneous coronary intervention
Anesthesiology 2008109596604
17
Anesthetic implications of revascularization
  • So if BMS to be inserted elective surgery is
    recommended to postpone for 6-8 wks.
  • If DES to be inserted, elective surgery is
    recommended to be postponed for at least 12
    months.
  • Revascularization by CABG, postpone elective
    surgery for 3-6 months.

18
  • What intraoperative monitors would you use?

19
Monitoring
  • An important goal of when selecting
    intraoperative monitors for patient with ischemic
    heart disease is select those that allow early
    detection of myocardial ischemia.
  • Electrocardiography the simplest, most cost
    effective method to detect myocardial ischemia by
    focusing changes in ST-segment changes

20
Monitoring
  • ST-segment changes such as depression or
    elevation of at least 1mm.
  • The degree of ST segment depression parallels
    the severity of myocardial ischemia.
  • Visual detection of ST segment IS unreliable,
    computerized ST segment analysis has been
    incorporated in electrocardiography monitor.
  • Traditionally, monitoring two leads, II and V5
    has been standard.

21
  • The lead sensitivity in detecting myocardial
    Ischemia is displayed,
  • The combination of lead II and V5 Provides the
    greatest ability to detect ischemia and Rhythm
    disturbances.

22
Intraoperative monitors
  • Pulse oximetry ( to assess arterial oxygenation).
  • Invasive blood pressure (for early detection of
    hemodynamic instability)
  • Capnography (to determine continual end-tidal CO2
    analysis specially if laparoscopic
    cholecystectomy was the selected procedure)
  • Body temperature (to avoid intraoperative
    hypothermia which predispose to shivering on
    awaking, leading to abrupt increase in oxygen
    consumption )

23
Intraoperative monitors
  • Urine output using Foleys catheter.
  • PAC a number of studies reported that PAC is an
    insensitive monitor for myocardial ischemia and
    should not be inserted for this as a primary
    indication.
  • TEE by detection of new wall motion abnormality.
    It's use here is not beneficial as it must be
    inserted after induction and removed before
    extubation, thus missing the critical time of
    hemodynamic changes, also deep gastric views will
    interfere with the surgical field.

24
Q5What additional drugs would you have prepared?
  • Drugs used in treatment of intraoperative
    myocardial ischemia must be available, and
    treatment should be instituted when there are 1
    mm ST segment changes on ECG.
  • Aggressive pharmacological treatment of changes
    in heart rate and/or blood pressure is indicated.
  • A persistent increase in heart rate can be
    treated by intravenous administration of beta
    blocker such as esmolol.

25
Q5What additional drugs would you have prepared?
  • Nitroglycerine is more than appropriate when
    myocardial ischemia is associated with normal or
    elevated blood pressure. Nitroglycerine induce
    coronary vasodilation and decrease in preload
    facilitate improvement of subendocardial blood
    flow.
  • Sympathomimetic drugs must be available to treat
    hypotension to restore coronary perfusion
    pressure, also fluid infusion can be usful to
    help restore blood pressure.

26
Q6What anesthetic technique would you use?
  • The basic challenge during anesthesia in patient
    with ischemic heart disease are
  • To prevent myocardial ischemia by optimizing
    myocardial oxygen supply and reducing myocardial
    oxygen demand.
  • To monitor for ischemia and to treat ischemia if
    it develops.

27
Q6What anesthetic technique would you use?
  • So avoid tachycardia as it increase oxygen
    requirements and decrease the diastolic time and
    thus the coronary blood flow.
  • Avoid hyperventilation, because hypocapnia may
    cause coronary artery vasoconstriction.
  • Intraoperative events associated with systolic
    hypertension, arterial hypoxemia, hypotension can
    adversely affect patients with ischemic heart.

28
Laparoscopic versus open cholecystectomy
  • The main hemodynamic alterations during
    laparoscopy is increase in systemic vascular
    resistance slight decrease in the cardiac output
    which proportionate with intraperitoneal
    pressure.
  • For those patients postoperative benefits of
    laparoscopy must be balanced against
    intraoperative risk when choice laparoscopy
    versus laparotomy.

29
Laparoscopic versus open cholecystectomy
  • Over the past years , patient with progressively
    more severe cardiac disease have safely undergone
    laparoscopy. Because of improved knowledge of
    hemodynamic repercussions of pneumoperitoneum.

30
Laparoscopic versus open cholecystectomy
  • So if laparoscopy is used
  • Slow insufflation.
  • Low intraabdominal pressure.
  • Hemodynamic optimization before pneumoperitoneum.
  • Patient tilt after insufflation.
  • Vasodilator drugs and sympathomimetic drugs must
    be available.

31
Anesthetic technique.
  • The laparoscopic cholecystectomy can be performed
    safely under spinal anesthesia as the sole
    anesthetic procedure and also showed the
    superiority of spinal anesthesia in postoperative
    pain control compared with the standard general
    anesthesia.
  • Also laparoscopic cholecystectomy has been
    reported performed under thoracic epidural
    anesthesia in patient with respiratory disease.

32
Segmental thoracic spinal anesthesia
  • A new technique introduced by Van Zandert in
    2006, a case report of laparoscopic
    cholecystectomy in a patient with severe
    respiratory lung disease. 1 ml plain bupivacaine
    plus sufentanil 2.5 µg (0.5 ml) injected
    intrathecally at the level of 10 th thoracic
    interspinous space.
  • Within 3 min a segmental sensory (pinprick)
    block, extending between the third thoracic and
    second lumbar dermatomes, was obtained, but
    without any motor weakness in the legs or hint of
    respiratory distress.

33
Segmental thoracic spinal anesthesia
  • Mean arterial pressure changes

34
Segmental thoracic spinal anesthesia
  • Postoperative pain

35
Postoperative management
  • The postoperative period appears to present the
    highest risk for cardiac morbidity and mortality.
  • During this period, 67 of the ischemic events
    occurs.
  • This period characterized by increase in heart
    rate, blood pressure, sympathetic discharge and
    hypercoagulability.

36
Postoperative management
  • Postoperative myocardial ischemia occurs in about
    33 of high risk patient.
  • Most of Those events (50) are silent.
  • Most cardiac events occurs in the first 48 hours
    postoperatively, delayed cardiac events can occur.

37
Postoperative management
  • The goals of postoperative management are the
    same as intraoperative management
  • Prevent ischemia
  • Monitor ischemia
  • Treat ischemia
  • Shivering, pain, hypoxemia, hypercarbia, sepsis
    and hemorrhage lead to increased oxygen supply /
    demand imbalance which in turn precipitate
    myocardial ischemia.

38
Postoperative management
  • Effective pain management is essential to prevent
    adverse outcomes.
  • PCA and PCEA are the most effective.
  • Effective pain management leads to a reduction
    in postoperative catecholamine surge and
    hypercoagulability.

39
Postoperative management
  • Patient with ischemic heart disease is adversely
    affected by anemia. Evidence suggest that
    transfusion are rarely beneficial if hemoglobin
    level exceeds 10 gm.
  • Avoid postoperative hypothermia and hypovolemia.

40
Postoperative management
  • Measurement of biomarkers of cardiac injury.
  • They are normally not present in the plasma so
    high signal to noise ratio.

Cardiac specific Troponin I and T is the
preferred marker due to high sensitivity.
41
THANK YOU
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