Student Presentations (CEA) Flashcards
GETA Advantages
GETA & muscle relaxation provide optimal surgical field
More control of VS
Greater patient comfort
Cerebral protection : Can regulate PO2, PCO2, and MAP
How does GETA provide cerebral Protection?
Cerebral protection by decreasing CMRO2 and redistributing BF to potential ischemia areas
With GETA Maintain hemodynamic stability →
cerebral perfusion and minimize cardiac depression
CEA REGIONAL Advantages:
Maintain BP stability
Facilitate continuous neurological assessment of the awake patient
Decreases length of stay in ICU
CEA REGIONAL DISADVANTAGES:
Phrenic nerve paralysis Hemorrhage Absence of cerebral protection Conversion to general may be difficult CN dysfunction
Hemodynamic management of Hypotension
Measures to control BP
Inhaled agents at 1 MAC Titrate vasoactive agents
Measure to control BP with Hypotension : Vasopressors
Infusion 40-80 mcg/min IV bolus 40-200 mcg Phenylephrine
Vasopressor IV bolus 5-10 mg Ephedrine
Antithrombotic Infusion 42 mL/hr Dextran
Why phenylephrine good with hemodynamics management of hypotension
Phenylephrine drip arterial>venous
Increases SVR, CVP, ICP (increases CBF)
Hemodynamic management of Hypotension
Measures to control BP Ephedrine : Mechanism of action, may cause?
Direct alpha/beta agonist and indirect by releasing NE postsynaptic nerve terminals. may cause bronchospasm. I
Hemodynamic management of Hypotension Ephedrine and PVR
ncreases PVR, bronchodilates,
Ephedrine max dose and when to avoid?
Max dose 50 mg. avoid tachy.
Dextran Mechanism of action
decreases platelet aggregation (and Factor 8 vW) which improves collateral circulation.This can also prevent a thrombus from forming at the suture line
Dextran should be started
slowly and patient observed for possible allergic reactions.
Dextran improves
Improves blood flow through microcirculation by decreasing blood viscosity Prolong bleeding time (max 20mL/kg/day)
Hemodynamics management of Hypertension
Esp. HTN • due to
carotid sinus stimulation or loss of baroreceptors
Hemodynamics management of Hypertension Short acting
IV bolus 100 mcg/mL Nitroglycerine
Hemodynamics management of Hypertension Long acting
IV bolus 5-10 mg Hydralazine
Hemodynamics management of Hypertension Selective β-blocker
Short acting IV bolus 0.5-1 mg/kg Esmolol
Hemodynamics management of Hypertension α1 Nonselective β-blocker
Long acting IV bolus 10-20 mg Labetalol
Why is esmolol a good choice?
Esmolol is a good choice short onset 2 mins and duration 10-30 mins T(1/2) 9 mins
Labetalol dosing
5-200 mcg/min Drip titrated to effect. IV push (100mcg/ml)
NTG cerebral dilations and
helps cerebral perfusion (primary venous dilator) being replaced by
Labetalol prevent
HTN post CEA 10-20 mg q10 mins
Hydralazine primary
arterial dilator.
Hydralazine onset, duration and max dose
Onset 10-20 mins/Duration 3-6 hrs. Can give every 15 mins MAX dose
Hemodynamic control during cross-clamping
Placed from
the proximal (common carotid artery) to the distal (internal carotid artery) Maintains cerebral blood flow during carotid artery cross-clamping
BEFORE clamp is applied you want to
decrease BP to help prevent spike in BP. This is when Heparin is given and can cause hypotension
Surgeon will ask for heparin
bolus BEFORE carotid clamping. Once you give the heparin, announce to surgeon 3-minute mark and this is when the carotid clamp is being placed. •
DURING clamping you want to keep
patients deep
Vessel clamped first
Internal carotid is cross-clamped first. •
Clamping and MAP
MAP 10-20% above baseline to enhance collateral circulation.
SBP and Clamping and why?
SBP < 160 as a guideline, surgeon may have preference This is to avoid cerebral hyperperfusion, excessive bleeding, and myocardial stress. •
Clamping, AFTER by the time the clamp is removed, where do you want preload?
preload at baseline or just above.
After clamp is removed what do you do?
Give protamine 0.5 mg for every 100 units of heparin given. Give slowly because it can cause hypotension • Be sure to document clamp time.
Heparin binds to
Antithrombin 3
Order of clamping:
internal → common → external (ICE)
When unclamping, the order is reversed
external → common →internal
ASA/antihypertensives
continued
Anytime you are using heparin and protamine,
have ACT available but may not use for this case
allow for neurological assessments
Low-dose narcotics
Intraop medication 2 meds and common practice is?
Fentanyl 1-2 mcg/kg or remifentanil infusion 0.05 mcg/kg/min
Balanced general anesthesia is common practice.
IV anesthetics and VA
Combination of IV and inhalation agents with narcotics. • Iso up to 0.6% • Sevo 1% • Remifentanil can reduce MAC requirements
If using Nitrous, can be used up to
50% but may increase the size of air emboli (can increase CBF and CMRO2). • Turn off during cross-clamping.
Propofol may be administered for its
neuroprotective properties
Propofol has neuroprotective properties because it will
decrease cerebral metabolic rate of O2 consumption, constrict normally reactive cerebral blood vessels and lead to a redistribution of CBF toward potentially ischemic areas.
Etomidate and any of the non-depolarizing NMB and fentanyl have
minimal effects on CBF and cerebral metabolic oxygen consumption
Remember…. CMRO2 and CBF
CMRO2 ↑ or ↓ so does CBF. (normal 3.0-3.8 mL O2/100 gm brain
Aspirin or antiplatelet therapy is
usually started preoperative to decrease the risk of preop thrombotic complications.
Aspirin can
be continued until the day of surgery
Premedication
midazolam 1-3 mg is preferable to opiates
Antibiotics
Cefazolin 1-2 g IV q 6 hours
Coumadin should be
stopped 5-7 days before surgery and aspirin may continued
Avoid large doses of
benzodiazepines to avoid longer sedation and hypercarbia w/ depressed respirations
CEA patients:Be aware that these patients may
have been treated with platelet anti-aggregates Aspirin should be continued up to the day of surgery
CEA and positioning
Supine with shoulder roll HOB slightly elevated with head is slightly extended and tilted away from operative side.
CEA and arms positioninig
Bilateral arms are tucked at side.
Secure ETT on
pposite of side of mouth from operative side
Positioning concerns Cardiac Measure BP
in arm with higher reading
Aortocaval compression : Resp disturbances
Respiratory ↓ FRC
Neurological : Head and blood flow (position)
Hyperextension & lateral rotation of head may lead to cerebral ischemia Nerve injury
If BP different,
BP cuff must be placed on extremity with higher reading. (measured intraop and postop)
Aortocaval compression may occur in
obese patients. S/S hypotension Decreased FRC due to displacement of diaphragm.
Smoking cessation
at least the night before to increase O2 carrying capacity by decreasing CO2 levels
Laying arm supine to prevent.
Ulnar nerve injury.
Risk of what nerve injury with head positioning
Cervical plexus injury due to head/neck position. •Avoid overstretching
Cranial nerve injury:
Recurrent/superior laryngeal nerve Hypoglossal nerve (tongue deviates to the side of injury)
Lower lip weakness
Mandibular br. Of facial nerve
Post op complications: Hyperperfusion syndrome
Hyperperfusion syndrome occurs from long-term loss of autoregulation.
The brain is not used to increased BF and cerebral vessels cannot constrict to compensate for increased BF. (hemorrhage and cerebral edema can occur.
Post op complications: Hyperperfusion syndrome signs and symptoms
WATCH for confusion and seizures. Pts may c/o ipsilateral HA, blurred vision, and facial or eye pain.(Hyperemia)
Post op complications: HTN: when does it occur
HTN occurs d/t loss of baroreceptors (may take a few days to achieve BP control).
Occurs in the immediate post-operative period, often with pts with pre-existing HTN.
Post OP HTN peaks when
Peaks 2-3 hrs after surgery and may persist for 24 hrs.
Post OP HTN and why it needs to be treated?
Needs to be treated to avoid cerebral edema, MI, and hematoma formation. Be sure BP cuff is on same arm as intraop
Post op complications. Hypotension related to
Related to volume status of patient. Can be treated with fluids, some may need vasopressors.
Post OP HOTN may be also related to ? What should you monitor
myocardial ischemia. MONITOR EKG FOR ISCHEMIC CHANGES
HOtN monitor in what leads for ischemic changes?
CHANGES IN LEADS 2, V4, V5.
Post OP Leading cause of death after CEA
MI
Hematoma formation and bleeding is common d/t .
heparin and dextran. Patient may need to return to OR to cauterize bleeding.
Must be assessed and treated promptly
Swelling; because it can compromise airway.
If intubation required, use a
Smaller tube.
Post OP Complications common complication and occurs due to
inadequate blood flow through the circle of Willis during carotid clamping or from embolized debris
Patients are routinely
monitored in ICU to observe for any postop complications
