SEDATION DURING REGIONAL ANESTHESIA

Made Wiryana

UNCOMFORTABLE SURGICAL PROCEDURE UNDER LOCAL OR REGIONAL ANESTHESIA

Subcutaneous multiple injection (e.g cosmetic surgery) of local anesthetic solution is often painful

Traction on deep structure and immobile for prolonged periods on narrow operating table cause significant discomfort

Environment, awake and aware during surgery extremely anxiety-provoking

Amnesia

Anxiolysis

Sedation

Systemic analgesia

Local or Regional technique are supplemented with adjunctive drugs for

Monitored Anaesthesia Care (MAC)

SEDATION CAN BE PROVIDE BY

Preoperative explanation of the procedure

Ongoing verbal communication during the operation

Low levels of visual and auditory stimuli in the operating room

Keeping the patient warm

Titrated sedative and analgesic drugs to avoid compromising patient safety

SEDATION IS A BALANCING ACT

RisksRisks BenefitsBenefits

Supplemental oxygen is strongly recommended to avoid haemoglobin oxygen desaturation

Usual monitoring devices and emergency resuscitation equipment should be immediately available

Emergency equipment * Oxygen with nasal cannula / mask* Ambu Bag with mask* Suction* Crash Cart* Airway box* Reversal Agents

Complications* Usually related to medications / patient response* Respiratory Depression

- Patient stimulation may be all that’s needed- Consider use of above emergency equipment

* Aspiration- Suction - May be silent. Watch skin color and SpO2

* Hemodynamic instability- Consider fluid bolus

* For any complication, consider ACLS guidelines / calling a code (2-4700)

• Assistant Responsibilities

– Patient assessment and appropriate documentation throughout the procedure

– Reassure patient and monitor patient awareness.

– Provide comfort measures as needed

– Notify clinician of changes / concerns.

– Documentation of required parameters.

The Assistant is not to leave patient bedside for any reason during the procedure (although may assist the clinician with short, interruptible tasks) The assistant must be able to drop those tasks if the patient needs attention)

CHOICE OF SEDATIVE AGENTS

Benzodiazepines

Opioid (narcotic)

Non-opioid (NSID) analgesics Sub-anaesthetic doses of sedative-hypnotics (e.g. barbiturates, etomidate, propofol, and ketamine

Inhalational technique is avoid for many reasons: pungent smell and increase PONV, make them unacceptable

BENZODIAZEPINES

DiazepamProduce anxiolysis, amnesia, and sedation ( CNS depression

is dose dependent), these effects prolonged in elderly, and undesirable for ambulatory patients

Has long elimination (24-48 hr) and hangover

MidazolamProduces more profound anxiolysis, amnesia , and sedationDoes not cause pain on injectionRapid acting, half-life 2-4 hrTitration is desired to minimized side-effects

KETAMINPhencyclidine derivative which can produce dissociative sedative

Subhypnotic doses (0.25-0.75 mg/kg iv) may useful for sedation and amnesia for local or regional anesthesia

Supplemental analgesia

Administering with benzodiazepine or other sedative drugs may reduce the side effects

Low dose ketamin (25 µg/kg/min) combined with midazolam or propofol is increasing in popularity at the present time

PROPOFOL

Infusion at sub-hypnotic dose (2-5 mg/min) may produce varying degrees of sedation. This doses typically equivalent with thiopenton 3-9 mg/min, midazolam 0.06-0.18 mg/min, and etomidate 0.2-0.6 mg/min

Rapid recovery

Reduce the incidence of over sedation and side-effects (PONV, respiratory and cardiovascular variables)

ANALGESIC ADJUVANTS

OpioidCombination these drugs can enhance the

degree of sedation and improve surgical condition ( prevent discomfort from pressure and traction )

Combinations of midazolam –alfentanyl and propofol-fentanyl have been reported to provide highly satisfactory

NSAIDsCombination of ketorolac-sedative drugs is

becoming increasingly popular as a supplemental

The quality of analgesia of ketorolac 1 mg/kg was similar with fentanyl 3µg/kg iv

Incidence of pruritus and PONV much reduced by ketorolac

Alpha-2 Agonists

Clonidine and dexmedetomidine have been consderable sedative, anxiolytic, and analgetic sparing properties

Dexmedetomidine is becoming popular as adjuvant during MAC in outpatients

Dexmedetomidine has good recovery from sedative-anxiolytic

However dexmedetomidine has been associated with a high incidence of bradycardia

Further investigations are require in modern anesthetic practice

PROCEDURAL SEDATION –PHARMACOLOGIC CONSIDERATIONS

If respiratory depression and/or hemodynamic instability occurs, consider use

of reversal agents.

Patient-Controlled Sedation

• The level of stimulation and discomfort may change throughout the operative procedure, so levels of sedation may be required at different times

• The popularity of PCA resulted the idea of the use of PCS (Zelcer, et al)

• A midazolam-fentanyl mixture reported a higher degree of intra-operative comfort (Park WY and Watkins PA)

• Propofol bolus of 0.7 mg/kg and lockout interval of three minutes was reported as a high level satisfaction (Grattidge P, Osborne GA, et al)

Summary

Regional anesthetic techniques are increasing in popularity because of the improved recovery profiles

Intravenous adjuvants can provide patient comfort

Titrated infusion of rapid and short acting sedative drugs should enhance patient safety

Vigilant monitoring, supplemental oxygen, and the availability ressucitation equipment are strongly recommended

Newer sedative drugs with more specific action, shorter durations and reduced side-effects as well as newer techniques like PCS (Patient Control Sedation) should improve patient safety and comfort during regional anesthesia

The The End.End.Thank Thank You!You!