premedication mgmc (1)

PREMEDICATION

Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics PhD (physio)Mahatma Gandhi medical college and research institute – Puducherry – India

WHY WE NEED ?? Sedation and anxiolysis Analgesia and amnesia Antisialagogue effect To maintain hemodynamic stability, including

decrease in autonomic response To prevent and/or minimize the impact of

aspiration To decrease postoperative nausea and vomiting Prophylaxis against allergic reaction VAAAAAS-- pneumonic

BEFORE WE WRITE !! Patient age and weight Physical status Levels of anxiety and pain Previous history of drug use or abuse History of postoperative nausea,

vomiting or motion sickness Drug allergies Elective or emergency surgery Inpatient or outpatient status Familiarity with drugs

PSYCHOLOGY Anxiety 40 -80 %

55 % in one study Counselling Drugs

WHEN TO ADMINISTER

Drug , route

Choose so that the peak action time is at their entry into the operating room

BENZODIAZEPINES Sedation Anxiolysis No nausea but No analgesia Excess sedation, paradoxical agitation especially in Old age ?? oral, IV, spray midaz, oral diazepam .Lorazepam Sublingual – midaz can be used

OTHER DRUGS Oxazepam Temazepam Triazolam Alprazolam

ANTIHISTAMINICS (H1) Sedation Anticholinergic Antiemetic

Diphenhydramine – oral dose of 50 mg

OPIOIDS Previous Morphine and pethidine IM

Now fentanyl IV

OPIOIDS ++ AND --- Where we need analgesia Ortho IV and arterial lines Decrease anaesthetic requirements

But respiratory depression, Sphincter of Oddi, PONV – problems

ANTISIALOGOGUES Popular in ether days

Now only in Ketamine Fibreoptic intubation

REDUCTION IN VAGAL RELEXES (CLINICAL SCENARIO)

Traction of ocular muscles Second dose of scoline Propofol, fentanyl, halothane Atropine and glyco pyrollate But – problems central anticholinergic syndrome,

tachycardia, blocking sweat glands ??

ADRENERGIC AGONISTS

Clonidine in doses of 2.5 to 5 µg/kg – oral sedation, prevent hypertension and tachycardia

from endotracheal intubation and surgical stimulation

Hypotensive anaesthesia IM,IV – OK

ASPIRATION pH of 2.5 and a volume of 25 ml

Danger zone

Ranitidine , famotidine, nizatidine are H2 blockers

ANTACIDS Nonparticulate antacid 0.3 M sodium

citrate

Colloid antacid suspension

Immediate , no lag time Increase volume, with food ??

OMEPRAZOLE Intravenous doses of 40 mg 30 minutes

before induction have been used. Oral doses of 40 to 80 mg must be

given 2 to 4 hours before surgery to be effective

Other PPIs – used

GASTROKINETIC AGENTS

Gastrokinetic agents are useful because of their effectiveness in reducing gastric fluid volume.

Metoclopramide Increased gastric emptying – but no

guaranteed emptiness of stomach Antiemetic No change in pH

AT THE END ?? ANTIEMESIS Many anesthesiologists prefer not to

administer antiemetics as part of a preoperative regimen, but believe that antiemetics should be administered intravenously just before they are needed at the conclusion of surgery.

Droperidol, metoclopramide, ondansetron, and dexamethasone

PROMETHAZINE Sedation Anxiolysis Antiemesis Alpha blocker Anticholinergic

THEY ARE NOT PREMEDICANTS IN STRICT SENSE BUT WE USE

Steroids Antibiotics Insulin Methadone

ANTIBIOTICS Infective endocarditis prophylaxis Probable contamination Immunosupressed Diabetic On steroids Cephalosporin –ok around one hour prior Vancomycin 2 hours prior Tourniquet !! Give antibiotics before

inflation

STEROIDS consider treatment in any patient who

has received corticosteroid therapy for at least 1 month in the past 6 to 12 months.

80 mg 6 hourly Why ?? 300 mg / day – maximal daily

production to stress

OTHER PREMEDICANTS TO CONTINUE Beta blockers Thyroxine Statins

And the other dugs he /she is taking for systemic illness

DEEP VEIN THROMBOSIS Heparin

Warfarin

Clopidogrel

When to use and stop – guidelines are there

IN A CHILD ??

parental presence on induction of anesthesia

an increase in heart rate and skin conductance levels in mothers

Oral midaz better than parent and the combined is not very superior

IV midaz – wait for 4.8 minutes Intranasal – 10 minutes

BENZODIAZEPINES IN PAEDIATRICS Lorazepam slow onset and offset of action, and

therefore is better used for inpatients

Diazepam immature liver function that would lead

to a prolonged half life

PEDIATRIC VS. ADULT PATIENTS Vagolysis Anticholinergic Anxiolysis Oral/ nasal/SL routes IM ??

PEDIATRICS Upto 6 months – no problem in parental

separation

6 months to 5 years -- maximal psychological problem and anxiety

5 years and above – easy to convince

DEXMED PREMED

Intranasal dexmedetomidine produces more sedation than oral midazolam when children were separated from their parents and at induction of anesthesia

KETAMINE

Nasal transmucosal ketamine at a dose of 6 mg/kg is also effective in sedating children within 20 to 40 minutes before induction of anesthesia.

Oral ketamine, IM ketamine , IV ketamine

PATCHES FOR VENIPUNCTURE EMLA cream (eutectic mixture of local anesthetic), is a mixture of two local anesthetics

(2.5% lidocaine and 2.5% prilocaine). ELA-Max (4% lidocaine) ,Ametop (4% tetracaine )The S-Caine Patch (eutectic mixture of

lignocaine and tetracaine – 70 mg of each drug/ patch )

SUMMARY Goals Factors Route Drugs -- benzo, opioids,

anticholinergics, promethazine, clonidine, aspiration,antiemetics others

Paediatric

Thank you all