by mai mohsen abdel aziz, md. in recent years, the importance of appropriate intraoperative...

By Mai Mohsen Abdel Aziz, MD

In recent years, the importance of appropriate intraoperative anesthesia and analgesia during cardiac surgery has become recognized as an important factor in postoperative recovery However little attention has been focused on postoperative sedation and analgesia in the pediatric ICU

Separation from parents Invasive procedures Disruption of usual day-night cycle Unfamiliar people and machines Physiological causes of agitation have to be excluded ; - Hypoxemia - Hypercapnia - Cerebral hypoperfusion due to reduced COP

Inadequate analgesia and postsurgical stress response metabolic, humoral, and hemodynamic response following injury or surgery. Neuroendocrine cascade leads to increased oxygen consumption, increased carbon dioxide production, generalized catabolic state with a negative nitrogen balance. Recent studies have concluded that inadequate pain control causes long term dysregulation of nociceptive mechanisms which may change behavior and responses to future pain stimuli.

Agent to be used Mode of administration Route of delivery

Rapid onset Predictable duration of activity Effects dissipate rapidly when agent discontinued Easy to titrate by continuous infusion Limited effects on cardiorespiratory function Effects and duration not altered by renal or hepatic disease Wide therapeutic index No interference with effect or metabolism by other drugs

Benzodiazepines Opioids Ketamine Propofol Chloral hydrate Phenothiazines Barbiturates NSAID Acetaminophen -2 agonists Most drugs can have deleterious effects on cardiorespiratory function therefore close monitoring of patients cardiorespiratory status in accordance with guidelines of the American Academy of Pediatrics

Sedatives and analgesics should not be administered strictly on a per Kg basis Dosage recommendations are meant as guidelines for starting doses Actual amount administered should be titrated to achieve the desired level of sedation or analgesia Significant interpatient variability in infusion requirements

A broad term that facilitate several goals; Unconsciousness or reduction in conscious level Reduced awareness Loss of explicit and implicit memory Compliance with the need to lie attached to monitors and invasive lines Prevention of distress

MinimalModerateDeep General DescriptionAnxiolysisConsciousDeep sleep Responsiveness Airway Ventilation Cardiovascular appropriate Unaffected Purposeful to light stimulation No intervention Adequate Maintained Purposeful to pain stimulation () Intervention () Inadequate () Maintained SEDATION LEVELS Risk of Adverse Event No Sedation Mild Sedation Moderate Sedation Continuous monitoring is mandatory; SpO2 ECG RR BP +/- etCO2

Comfort scale Range (8-40) Excessive (8-16) Adequate (17-26) Insufficient (27-40)

1- All sedative drugs suppress the CNS 2- Respiratory depression: the most significant adverse effect following sedative drug administration a. Impaired airway control - the single most serious adverse event b. Hypoventilation 3- Depth of sedation is a continuum mild sedation general anesthesia 4-The greater depth of sedation the greater risk

Pharyngeal Segment Nasal Segment Tracheal Segment THE UPPER AIRWAY Pharyngeal collapse during sedation inhibition IX X P(-) P(O)

pCO 2 Minute ventilation (l/min) VENTILATION HYPOVENTILATION DURING SEDATION sedation

First line agents hypnosis NO analgesia action in the limbic anxiolysis system via inhibitory GABA antegrade amnesia Abstinence syndrome anticonvulsant effect after prolonged use May produce hypotension with decrease in COP>20% in postcardiac surgical patients Decreased central sympathetic output which may decrease systemic vascular resistance

Sedating, variable amnesia, anxiolytic Irritating to veins, pain in injection(propylen glycol) Highly lipid soluble, rapid onset Multiple active metabolites Advantage for prolonged sedation Disadvantage for rapid arousal Not recommended for continuous infusion Half-life 12-24 hrs Hepatic metabolism

Improved amnesia No active metabolites Half life 4-12 hours Metabolized by glucuronyl transferase Less influence from other drugs Better preserved in patients with liver disease

Rapid onset Rapid metabolism Good amnesia Water soluble, no pain with injection Half life 2 -4 hours Hepatic metabolism with renal excretion Active hydroxy-metabolite may accumulate Other routes of administration Oral,Nasal,Rectal,Sublingual Reports of dystonia and choreoathetosis post infusion, greater risk in neonates Heparin decreases protein binding, increases free drug Dosing ranging from 0.05-0.2 mg/kg/hr

RESPIRATORY DEPRESSION Less than narcotics, but potentiated with narcotics Dose related Reversal Flumazenil - benzodiazepine receptor antagonist Choreoathetoid movement disorder Tolerance Dependence Withdrawal carefully and slowly if administered > 7-10 days Signs of withdrawal - tremor, tachycardia, hypertension, Rapid withdrawal may promote seizures

First line analgesia sedation no amnesia delayed gastric emptying decreased intestinal peristalsis urinary retention Commonly used narcotics: Morphine Fentanyl Methadone

ROUTE OF ADMINISTRATION IV Oral Transmucosal Transdermal MODE OF ADMINISTRATION Intermittent/on demand (as necessary) Fixed interval Continuous infusion PCA

Intravenous bolus administration Common though antiquated PRN - as needed Half-life of drug determines interval Disadvantage of pain breakthrough

Utilized when prolonged analgesia and sedation needed Better analgesia, initial accurate bolus important Need for dedicated IV site

Patient controlled analgesia Allows patient to administer a preset amount of narcotic at preselected intervals Improved analgesia with decreased narcotic use Option to include low basal rate Nurse controlled analgesia Eliminates delay Allows delivery via a closed system

Gold standard hepatic metabolism depresses respiration depresses rate over tidal volume histamine mediated hypotension esp in hypovolemic Can block compensatory catecholamine effect Prolonged clearance in neonates

IV intermittent 0.1 mg/kg q 3 - 4 hrs IV continuous 0.05 mg - 0.1 mg/kg/hr PCA dosing Initial dosing: 50 mcg/kg q 10 minutes until comfortable Demand dose: 20 - 40 mcg/kg Lock-out period: 10 minutes 4-hour limit: 0.25 mg/kg

Synthetic opiate, 100 x morphine rapid onset highly lipophilic hepatic metabolism minimal hemodynamic effect chest wall rigidity Short distribution t 1/2, long elimination t 1/2, Blunts pulmonary vascular responses

IV intermittent dosing 1-2 mcg/kg q 1-2 hrs IV continuous dosing 1-2 mcg/kg/hr Transdermal delivery system available Not recommended in children less than 12 yrs 25,50,75,100 mcg/hr 25 mcg/hr is equivalent to 15 mg morphine in a 24 hr period

Potency equivalent to morphine Half life 12-24 hrs Prolonged duration of action abolishes the need for continuous infusion

RESPIRATORY DEPRESSION Reversal - Nalaxone (Narcan) Full reversal 0.1 mg/kg Half life is less than narcotics IV,IM,Sub Q, ETT Abrupt reversal may result in nausea, vomiting, sweating, tachycardia, increased BP, and tremors Pruritis Individual variability and susceptibility, alleviated by Benadryl

Tolerance Need for increase in dose to achieve the same effect Generally develops after 2-3 days of frequent/continuous use Greater with fentanyl Treated by increasing the dose as needed DEPENDENCE Physiological state leading to abstinence syndrome on withdrawal of the drug, rare Generally develops after 7-10 days of sustained use Symptoms include: mydriasis, tachycardia, goose bumps, muscle jerks, vomiting, diarrhea, seizures, fever, hypertension Treated with gradual withdrawal of the drug

Dissociative IV anesthetic good amnesia analgesia water and lipid soluble crosses BBB

Pain with injection/infusion site Improved with use of 1% lidocaine Neurologic sequela Opisthotonic posturing Myoclonic movements Metabolic acidosis reported with use > 24 hrs Contraindicated for long term use Dosing 1 - 3 mg/kg induction 20 - 100 mcg/kg/min Increase infusion rate 5-10 mcg/kg/min increments of 5 - 10 minutes

Sedative hypnotic agent Metabolized in the liver to its active form, trichlorethanol Half life 8-12 hours Oral or rectal administration Onset of action delayed Not to exceed 100 mg/kg/day - i.e.: 25mg/kg/q 6 hrs Caution in children < 3 months or with hepatic dysfunction

Sedative Respiratory depression dose dependent Negative inotropic effects/vasodilation - decreased cardiac output Decreased cerebral O 2 consumption CBF ICP Anticonvulsant, Useful in patients with increased ICP Alkaline solution, often incompatible with TPN or meds.

Phenothiazine Thorazine Butyrophenones Droperidol Haloperidol Common in adult ICU, uncommon in PICU Side effects hypotension due to alpha blockade and extrapyramidal effects May be useful in the difficult to sedate child

Clonidine Selectivity: 2 : 1 250:1 t 1/2 10 hrs Antihypertensive PO, patch, epidural In opioid withdrawal Dexmedetomidine Selectivity: 2 : 1 1620:1 t 1/2 2 hrs Eliminated by liver/kidney Sedative Only available in IV form Precedex 200 ug/vial others : apraclonidine, detomidine, medetomidine

Dose dependent sedation, patients are easily arousable Anxiolysis Analgesia Reduces shivering Minimal respiratory depression Known action Hyperpolarization of LC neurons 2 A-receptor subtype Reversible (atipamezole)

Sinus pause/arrest Orthostatic hypotension Dry mouth Vasoconstriction

Continuous intravenous infusions of morphine or fentanyl are recommended for the relief of severe pain. Non-steroidal anti-inflammatory drugs or paracetamol may be used as adjuncts to opioids in certain patients.

Pain assessment should be performed regularly by using a scale appropriate to the age of the patient and routinely documented. The level of sedation should be regularly assessed and documented using a validated scoring system such as the COMFORT scale. Midazolam is the recommended agent for the majority of critically ill children requiring intravenous sedation and preferably by continuous infusion. Clonidine given by continuous intravenous infusion may be used as an alternative sedative agent to midazolam. Propofol should not be used to provide continuous sedation in critically ill children.

by mai mohsen abdel aziz, md. in recent years, the importance of appropriate intraoperative...

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