Intraoperative Small-Dose
Ketamine Enhances Analgesia
After Outpatient Knee
Arthroscopy
Elizabeth Mann, RN, BSN, SRNA
Oakland University-Beaumont
Hospital
Graduate Program of Nurse
Anesthesia
February 8, 2012
Article
Menigaux, C., Guignard, B., Fletcher, D.,
Sessler, D.I., Dupont, X., Chauvin, M. (2001).
Intraoperative small-dose ketamine
enhances analgesia after outpatient knee
arthroscopy. Anesthesia & Analgesia 93,
606-12.
Background
 Ketamine
had been previously been tested
in inpatient arthroscopic anterior ligament
repair proving better pain relief and faster
return to normal functional activity
 Standard treatment for outpatient
arthroscopy at the time of study
 NSAIDs
alone
 Combination with intraarticular Bupivacaine and
morphine.
Hypothesis
A
small intraoperative dose of
Ketamine will improve
postoperative analgesia and
facilitate ambulation after
arthroscopic meniscectomy and
that the benefits will last for
several days.
Study
 Double
blinded study
 50 patients: 25 in Control Group and 25 in
Ketamine Group
 Inclusion
 Patients
Criteria:
were all scheduled for elective
arthroscopic surgery
 ASA status I and II
 Between the ages of 18-60
Exclusion Criteria
 ASA
status >II
 Surgery performed under regional
anesthesia
 History of chronic pain
 Chronic use of analgesic medications
 Drug or alcohol abuse
 Psychiatric disorders
 Contraindications to NSAIDs
Pain Assessment Tools
 Verbal
rating scale (VRS) and visual analog scale
(VAS) while ambulating
 VAS: 0-100 mm, 0 is no pain and 100 is worst pain
 VRS:
0= no pain
 1= light pain
 2= moderate pain
 3= intense pain
 4= severe pain

Methods
 Consent
was obtained
 The hospital pharmacist prepared a 10 mL syringe
of either isotonic sodium chloride or 0.15 mg/kg
Ketamine diluted in isotonic sodium chloride
 The group assignments were made with a
computer generated random number table
 Patients and OR Staff were unaware of their
group assignment
Methods
 Patients
were premedicated with 100mg hydroxyzine
PO, 1-2 hours before surgery
 Induced with Propofol (2mg/kg) followed with
Alfentanil (20mcg/kg)
 LMA inserted
 Mechanically ventilated
 GA maintained with Propofol gtt (60-200
mcg/kg/min)


Titrated to maintain HR and MAP within 20% of
preoperative vitals
60% N2O in oxygen
Methods
 Same
surgeon
 Same technique
 Every patient received 20 mL 0.5%
Bupivacaine and 5 mg of Morphine
injected into knee joint before
tourniquet deflation
 Propofol gtt was discontinued after
trocars were removed from the knee
Methods
 Transferred
to PACU
 3 mg IV Morphine (every 5 minutes/PRN) until
VAS score was <30 mm or VRS score was <2
 Patients received 550 mg Naproxen PO
 Patients were discharged home
 Instructed
to take 550 mg Naproxen twice daily
 2 tablets of Di-Antalvic every 6 hours for pain (400
mg Acetaminophen/30 mg
dextropropoxyphene)
 Resume normal activity as soon as they could
Measurements in PACU
 Pain
scores were evaluated at both rest and
mobilization
 Recorded every 15 minutes x 1 hour, then at 2, 4,
and 6 hours after surgery
 Mobilization assessment stopped




VAS score >30 mm
VRS >2
Sedation score > 2 (patient somnolent, responds to
tactile stimulation)
HOTN (MAP <60) or Bradycardia (HR <50)
Questionnaires POD 1-3
 Assessed
pain during the night, at their first step, and
an over all rating (VAS)
 Number of painful events during the day (0-5, 6-10,
>10)
 Duration of walking during that day (0, <1 hour,1-3
hour, or normal)
 Number of doses of Di-Antalvic and any concomitant
medication used during the day
 Side effects
 Whether they experienced bad dreams
 Global score of patient satisfaction with pain control
Data Analysis
 Primary
end point: Post-op pain
 Secondary end point variables: Analgesic
consumption and return to normal walking.
 Statistical analysis was performed with NCSS 6.0
 Unpaired Student T-tests
 Age,
weight, length of surgery, amount of Propofol
and Alfentanil
 Time intervals to SV, LMA removal, arrival to PACU,
and discharge home
Data Analysis
 Mann-Whitney
 Analgesic
episodes
U-test
doses, sedation scores, and pain
 X2
 Frequency
 Results
of side effects
presented as +/- SD or median and
25-75th percentile ranges
 P< 0.05 was considered statistically
significant
Results



Control group required more Morphine titration in PACU
(P<0.05)
Ketamine group had lower VAS scores in PACU while
ambulating
Pain scores were lower in the Ketamine group (POD 1-3)





During the night
At their first step
During ambulation
Ketamine group required less additional narcotic (POD13)
There were no reports of N/V, dysphoria, hallucinations,
diplopia, cognitive or memory impairments in both
groups
Strengths/Limitations
 Strengths



No patients were excluded
All 50 patients returned the follow up
questionnaire
Double Blind Study
 Limitations


Small sample size
Difficult to study pain due to subjective
measurements
Conclusion
 This
study extended previous studies that
evaluated small dose ketamine benefits for
inpatient orthopedic procedures.
 It
provided evidence that a balanced
technique with Ketamine could provide
better analgesia and improve ambulation
without increasing adverse effects.