premedication mgmc (1)
TRANSCRIPT
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