INTRA VENOUS INDUCING AGENTS

DR N K AGRAWALJNMC,SAWANGI

What are the properties of an ideal IV agent?

Should act in one arm brain circulation time

Should not cause pain on induction

Should not be irritant

Should have short half life

Metabolites should be non active

Not hepatotoxic

Should not depend on renal for excretion

No respiratory depression

Should cause hallucination

No dissociation

Should have hemodynamic stability

Should not change cerebral blood flow

Least PONV

No allergic reaction

Useful for TIVA

Derivative of phenol

Have hypnotic properties

2-6 disopropofol

Alkyphenol are oil, highly lipid soluble

Ctenophore is 1% propofol,10% soybean oil,2.25 glycerol, and 1.2% purified egg

Fospropofol is USA FDA Aqua van

1 % excreted in urine,2% feces

Metabolized hepatic,kidney,lungs

Elimination Half life is 2-8 min

Distribution half life is 4min to 23 hrs

Dose is 1-2 mg/kg

Infusion is 200ug/kg/min

Act on GABA

Directly act on neurons of spinal card

At dose of 2.5 mg/kg induces hypnosis in 90-100 sec

It causes sedation,hypnosis,amnesia

Hypnosis lost for 6-10 min

Hallicination,sexual fantasis,opisthotonus have been reported

High doses are needed for less than 2 yr,with age dose requirement is reduced

Decreases arterial BP

Diastolic BP

Stroke volume

Peripheral resistance

Pawp

Pulmonary vascular resistance

HR may or may not

Myocardial blood flow reduced as well demand

Decreases ICT

Tolerance

Reduces CPP

Cp50

Apnea depends on dose, speed of injection,concommitent premedication

Uses and Doses of Intravenous Propofol Induction of general anaesthesia 1-

2.5 mg/kg IV dose reduced with increasing age

Maintenance of general anaesthesia 50-150 µg/kg/min IV combined with N2O or an opiate

Sedation 25-75 µg/kg/min IV Antiemetic 10-20 mg IV, can repeat every 5-10 min or start infusion of 10 µg/kg/min N2O, nitrous oxide.

Pain on injection

Hypotension

Myoclonus

Apnea

thromboplhebities

Highly alkaline

Prepared with water or normal saline

Stable for one week

Not compatible with pan.,vec,atra,sufen,alfen

Excreted through liver

Metabolites are inactive, water soluble ,excreted in urine

Bio transformation in four stage

oxidation

desulfuration

dealkylation

destruction

Dose is 4-5 mg/kg

Half life is 7-17 hrs

its affinity for fat, relatively large volume of distribution, and low rate of hepatic clearance, thiopental can accumulate in tissues, especially if given in large doses over a prolonged period. The plasma drug level increases when repeat doses of drug are given.

Act in one arm brain circulation time

Ultra short acting

Crosses blood brain barrier

Bound to albumin

Dose dependant CNS Depression

Decreases cerebral metabolic rate

Protect brain from ischemia

Reduces CMRO2

On injection garlic or onion test in 40%

Allergic reaction

Irritation

necrosis

Infuse normal saline

Heparin

Nerve block

Increases HR

Peripheral vascular resistance decreased

Negative inotropic effect

Fall in cardiac out put

Decreases ventricular filling

Decreases sympathetic outflow CNS

Depression

Apnea

Wood has listed the contraindications to IV barbiturate use.[227]

(1) When there is respiratory obstruction or an inadequate airway, thiopental may worsen respiratory depression.

(2) Severe cardiovascular instability or shock may preclude its use.

(3) Status asthmatics is a condition in which airway control and ventilation may be worsened further by thiopental.

(4) Porphyries may be precipitated or acute attacks may be accentuated by the administration of thiopental.

(5) Without proper equipment (IV instrumentation) and airway equipment (means of artificial ventilation), thiopental should not be administered.

It is imidazole derivative

Molecular wt 342.69

Water insoluble

Ph 6.9

Dose not precipitate

general anaesthesia 0.2-0.6 mg/kg IV

Maintenance of general anaesthesia 10 µg/kg/min IV with N2O and an opiate

Sedation and analgesia Limited to periods of brief sedation because of inhibition of corticosteroid synthesis N2O, nitrous oxide.

The primary action of etomidate on the CNS is hypnosis,

which is achieved in one arm–brain circulation after a normal induction dose (0.3 mg/kg).

Etomidate has no analgesic activity. Plasma levels required for the maintenance of anaesthesia are approximately 300 to 500 ng/mL, for sedation are 150 to 300 ng/mL, and for awakening are 150 to 250 ng/mL

mechanism by which etomidate produces hypnosis is fully known

Reduces CMR and CBF

No change in MAP

CPP maintain or increased

Dose not affect ventilation

No histamine release

No effect on co2 response

No effect on Pao2

PACO2 slightly increased

NO CHANGE IN

HR,MAP,STROKE VOLUME,CARDIAC INDEX,PAWP,

CVP,

It provide sedation hypnosis, anxiolysis

Analgesia sympatholysis

DOSE- 0.25 to 1 mg/kg

Metabolize in liver

2%

Metabolite are active

85% by kidney

14% via liver

Rapidly distributed and extensively metabolized in liver

Excreted through urine and feces

Sensitive half life 4-6 min

Half life 2-4 hours

SEDATIVE- the patients are awake and responsive

ANALGESIA-good analgesic, when given in epidural space action within 2-20 min

Absorbed in CSF Little effect on ICP CBF

Ventilatory response increased

Response to co2 increased

RR increased

Paco2 increased by 20%

Decrease in HR-Sympathetic vascular resistance

Hence decreases cardiac out put cardiac out put