Anesthesia and Renal Failure - Ahmad Hatoum

8/16/2019 Anesthesia and Renal Failure - Ahmad Hatoum

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Anesthesia and Renal Failure


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In renal failure, the induction dose of

which of the following should be

decreased ?

•

Propofol• Ketamine

• Thiopental

• Etomidate


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Induction Anesthetics

• Propofol: undergoes hepatic

biotransformation into inactive metabolites; in

renal failure duration of action is not affected

• Ketamine: hepatic metabolism and

redistribution are responsible for termination

of the anesthetic effects and


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Induction Anesthetics

• Thiopental: 85% is protein bound and in the

setting of uremia the free fraction is almost

doubled, so the induction dose should be

decreased

• Etomidate: 75% is protein bound so the free

fraction increases in renal failure; however

this increase is not clinically significant


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In renal failure, the induction dose of

which of the following should be

decreased ?

•

Propofol• Ketamine

• Thiopental

• Etomidate


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Volatile Anesthetics

• Nitrous Oxide: elimination is through

exhalation, so it is not affected by renal failure


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Fluoride Induced Nephrotoxicity

• Metabolism of sevoflurane, isoflurane,

methoxyflurane, enflurane and halothane

results in production of fluoride ions

• Nephrotoxicity is a result of 2 factors: the peak

fluoride concentration (with above 50 uM

toxic threshold) and the area under the curve

of serum fluoride concentration versus time


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• Isoflurane: 20 MAC-hours of isoflurane could

lead to serum flouride levels above 50uM,

however no postoperative renal dysfunction

was detected

• Sevoflurane: regularly 7% of patients who

receive sevoflurane will have serum flouride

levels above 50uM. Yet, no clinically significant

renal dysfunction was detected


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• Methoxyfluane and enflurane might cause

renal dysfunction especially when associated

with hypovolemia, shock and renal

vasoconstriction


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Sevoflurane and compound A

• Sevoflurane is degraded in basic carbon

dioxide absorbents, such as Barium Hydroxide

and Soda lime, into a vinyl ether called

compound A

• Compound A was proven to be nephrotoxic

when it reaches certain thershold levels that

differ among different animal species


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Sevoflurane and compound A

• Human studies have not associated

sevoflurane with any detectable postop

impairment of renal function

• Some clinicians recommemd that fresh gas

flow rate be al least 2L/min to avoid release of

compound A


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following is not affected by renal

failure?

• Succinylcholine

•

Rocuronium• Vecuronium

• Doxacurium

• Cisatracurium


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Renal Failure and Succinylcholine

• Succinylcholine: its duration of action is notsignificantly prolonged, so its use is justified inrapid sequence induction

• Renal failure patients are more prone tohyperkalemia and succinylcholine results in anincrease in serum potassium levels in normalsubjects (0.5mEq/L). Therefore, serum potassium

levels should be checked and normalized.

• Use of a continuous infusion is not recommendedsince its major metabolite succinylmonocholine is

active and dependent on renal excretion


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Intermediate acting Muscle Relaxants

• Vecuronium: has an active metabolite (3-desmethyl vecuronium) that accumulates in renalfailure causing an intubating dose to last around50% longer

• Rocuronium: pharmacokinetic studies on patientswith renal failure had conflicting results withrespect to the duration of action

• Atracurium and cisatracurium metabolism isindependent of renal and hepatic function, sothey are recommended in renal failure


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Laundanosine

• It is a breakdown product of Hofmann

elimination (of atracurium and cisatracurium)

that was found to cause seizures in

experimental animals.

• However, intensive care patients with renal

failure receiving prolonged infusions of

atracurium did not have any seizures


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Long acting muscle relaxant

•

Doxacurium and pipecuronium have reducedplasma clearance and prolonged duration of

action in renal failure patients


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following is not affected by renal

failure?

• Succinylcholine

•

Rocuronium• Vecuronium

• Doxacurium

• Cisatracurium


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Which of the following opioids is safe

in renal failure

• Meperidine

•

Fentanil• Sufentanil

• Morphine

• Remifentanil


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Opioids and Renal Failure

• Morphine undergoes hepatic metabolism tomorphine-3-glucuronide and morphine-6-

glucuronide. These metabolites can

accumulate in renal failure and result innarcosis and respiratory depression

• Merperidine is metabolised to normeperidinewhich might accumulate in renal failure

patients and result in CNS toxicity (seizures).


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• Fentanyl and alfentanyl are good choices in

renal failure since their metabolites are

inactive and the change in their free fraction isnot clinically significant

• Sufentanil has an active metabolite that mightaccumulate in renal failure upon chronic use

and result in prolonged narcosis


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• Remifentanil clearance is not affected by renal

failure

• It is metabolized to remifentanyl acid, whichwould accumulate in renal failure, but is 4,600

times less potent

• Thus, the clinical implications are limited


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Which of the following opioids is safe

in renal failure

• Meperidine

•

Fentanil• Sufentanil

• Morphine

• Remifentanil


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TURP syndrome

• In around 1.5 % of TURPs excessive

absorption of the irrigating solution may lead

to several symptoms described as TURP

syndrome

• Several irrigation solutions are available for

use during TURP, such as glycine, sorbitol,

mannitol and distilled water


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TURP syndrome

• The signs and symptoms can be divided into

those common to all irrigating solutions and

those peculiar to certain solutions.

• Excessive absorption of any of the solutions

might lead to fluid overload and hyponatremia


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Common Signs and Symptoms

• Fluid overload might manifest as hypertension,

bradycardia and pulmonary edema especially in

congestive heart failure patients

• Hyponatremia (if Na


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Glycine Solutions

• Glycine is an inhibitory neurotransmitter in

the cortex and retina

• Excessive absorption might lead to seizures

and post-op blindness that resolves when

glycine blood levels decrease


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Other solutions

• Distilled water might lead to hemolysis and

hyponatremia.

• Glucose solutions might cause hyperglycemia

•

Sortibol solutions could lead to hyperglycemiaand lactic acidosis


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Prophylactic measures

• To decrease fluid absorption, it is

recommended to:

1) Limit resection time to < 1 hour

2) Suspend the irrigating bag


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TURP Syndrome Treatment

• When symptoms and signs of TURP syndrome

occur:

1. Stop using the irrigation solution

2. If pulmonary and cardiac symptoms are

present, place the patient in reverse

Trendelenberg position to alleviate

symptoms by pooling blood in the lower

extremities

3. Electrolyte analysis: Sent blood for

electrolytes, creatinine, glucose and ABGs


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HyponatremiaTreatment

• If patients are symptomatic and have serum

[Na] < 120mEq/L, they should be corrected

with hypertonic saline at a rate < 100ml/hr till

they are asymptomatic or serum [Na] >120mEq/L

• Then hyponatremia is managed with fluid

restriction and loop diuretic (furosemide)


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Thank You

Anesthesia and Renal Failure - Ahmad Hatoum

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