Regional Anesthesia in the Outpatient Setting

Ravindra V. Prasad, MD

Department of Anesthesiology

UNC School of Medicine

Review3/30 – Ghia, Axillary Block4/1 – Wilkes, Axillary Block4/8 – Levin, SAB4/14 – Klein, Lower Extremity Blocks4/15 – Prasad, ???

OverviewRegional Anesthesia: general commentsUpper Extremity BlocksParavertebral BlocksNeuraxial BlocksLower Extremity Blocks

Regional: advantagesAvoid GA complicationsLess anesthetic required

faster wake-up? quicker recovery?

Faster ambulation, faster discharge N/V less common post-op pain minimized

Regional: problemsTimeEquipmentPersonnelGA still backup planSkill

regional techniques management of awake or LIGHTLY sedated

patients

Block PlacementMonitoringEmergency equipment and drugs should be

readily availableBlock equipment readied before startingPOSITIONINGSEDATION (preoperative, intraoperative)Patient selection

Upper Extremity Blocks

Brachial Plexus BlocksPeripheral Nerve Blocks

elbow wrist

Bier Blocks

Brachial Plexus

Dermatome Distribution

Brachial Plexus Blocks

Indications: surgery of upper extremityApproaches

Axillary Infraclavicular Supraclavicular Interscalene (ISB)

ISB: technique

EquipmentDrugsTechnique

ISB: complications

PneumothoraxPhrenic nerve paralysisHorner’s syndromeC6 root neuropathy (intraneural injection;

root pinned against C6 tubercle)

Bier Block

Intravenous Regional Anesthesia (IVRA)Described by Bier in 1908Intravenous injection of local anesthetics in an

extremity isolated from the systemic circulation

A simple technique which is easy to performWidespread use in surgical cases of short

duration

Bier Block: indications

Surgery of the extremities, especially hand and forearm

Surgery of short duration (less than 1 hour)Soft tissue procedures (block is less dense

than nerve blocks; may have pain if bony involvement)

Bier Block: contraindications

Disease processes or states prolonged tourniquet times contraindicated

(Sickle Cell Disease or Trait) more susceptible to toxic effects of agents used

(Heart Block)

Hypersensitivity/allergy to agents usedPatients with a painful extremityCertain patient body habitus

Bier Block: technique

Equipment tourniquet(s) with pressure gauge rubber bandage (Martin, Esmarch)

Drugs Local Anesthetics: Lidocaine 0.5% or

Prilocaine 0.5% Opioids Ketorolac

Bier Block: mechanisms of action

Direct action at nerve endingsDiffusion into nerve trunks

Nerve trunks consist of fascicles covered with epineurium

Blood vessels contained within the epineurium Capillaries within endoneurium extend

intraneurally as vasa nervorum Local anesthetic diffusion occurs from nerve core

to the periphery

Bier Block: complications

Local anesthetic systemic toxicity Premature tourniquet release, malfunctioning

tourniquet Leakage through intraosseous veins or ordinary

veins

Direct tissue local anesthetic toxicity (neuronal, muscular, vascular injury )

Ischemic injury (prolonged tourniquet time, excessive tourniquet pressure)

Bier Block: pearls

Tourniquet painTourniquet deflationProlonged surgeryLower extremity surgery

Paravertebral Blocks (PVB)

Paravertebral spaceSpinal root emerges

from intervertebral foramen, divides into dorsal and ventral rami and sympathetics

Unilateral motor, sensory, and sympathetic block

PVB Indications

Thoracic thoracotomy mastectomy nephrectomy cholecystectomy rib fractures post-thoracotomy pain post-mastectomy pain

Lumbar: inguinal hernia

PVB: technique

EquipmentDrugsTechnique

2.5-3 cm lateral to spinous process, caudal and 1-2 cm deep to transverse process

4-5 ml local anestheticVariations

PVB: risks

Complication Adults(319)

Children(48)

Greengrass(156)

Pleural puncture 3 1Pneumothorax, symptomatic 1 0 1Bloodstained aspirate 12 2Hypotension (requiring fluidor ephedrine)

16 0

Epidural involvement 2Epinephrine absorption 1

Reported failure rate 10-15%

PVB: breast surgery

Block T1-T6: go lateral to C7-T5.Greengrass:

Retrospective review, 156 blocks in 145 patients vs. 100 GA over 2-year period

85% block alone 91% block + local 2.6% complication (4/156)

PVB vs. GA: breast surgery

Complication PVB % GA %Require N/V med duringhospital stay

20 39

Narcotic analgesia requiredduring hospital stay

25 98

Discharged POD #0 96 76

PVB: inguinal hernia repair

Block T10-L2: go lateral to T10-L2Onset of surgical anesthesia 15-30 min

PVB: IH Repair, outcome22 patients. 3 converted to GA

1/3 had good block at emergence failure rate 2-3/22 = 9-14%

Of 20 “successful” blocks Onset of discomfort 14 11 hrs, first narcotic 22 18

hrs 13 (65%) no incisional discomfort for at least 10 hrs after

block 3 (15%) epidural spread

Klein, SM Greengrass RA Weltz C Warner DS, 1998

PVB: inguinal hernia, satisfaction

Satisfaction with anesthetic 24 hr 48 hrNot satisfied 0 0Satisfied 3 2Very satisfied 17 18

SAB DurationDisadvantagesAdvantages vs. epidural

Duration, SAB

Duration of Sensory Block, SABDrug Dose

(mg)2-Dermatomeregression (min)

CompleteResolution (min)

Prolongation by-Agonists (%)

Procaine 50-200 30-50 90-120 30-50Lidocaine 25-100 40-100 140-240 20-50Bupivacaine 5-20 90-140 240-380 20-50Tetracaine 5-20 90-140 240-380 50-100

Epidural

DurationDisadvantagesAdvantages vs. SAB

Duration, Epidural

Duration of Sensory Block, EpiduralDrug 2-Dermatome

regression (min)CompleteResolution (min)

Prolongation by-Agonists (%)

Chloroprocaine 3% 45-60 100-160 40-60Lidocaine 2% 60-100 160-200 40-80Mepivacaine 2% 60-100 160-200 40-80Ropivacaine 0.5-1.0% 90-180 240-420 NoEtidocaine 1-1.5% 120-240 300-460 NoBupivacaine 0.5-0.75% 120-240 300-460 No

Summary

Regional anesthesia is goodUse it!