Heesen M, Rijs K, Hilber N et al.
Anaesthesia 2019, 74, 1047-56. doi:10.1111/anae.14666
Investigate the effect of IV dex on post-op analgesia during single shot spinal anaesthesia
- Equivocal evidence so far
- 1133 patients. 17 trials
- High quality of reporting. Low risk of bias.
- Systematic literature search, then conventional meta-analysis (random effects model)
- Contacted authors to clarify details/ascertain morphine doses
- Trial sequential analysis for primary outcome
- Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to rate level of evidence
- Studies comparing dexamethasone with placebo or combination of dexamethasone with another drug compared with other drug alone
- Surgical procedures under single shot spinal or combined spinal-epidural
IV morphine in first 24 post-op hours (& equivalents)
- Time to first analgesic request
- # patients requiring rescue analgesia
- Use of NSAIDS
- Pain score (VAS/NRS)
- Duration of motor block
- Incidence of wound infections & healing complications
9 studies used 8mg dexamethasone.
10mg/4mg in 2 trials each.
0.1mg/kg in 3 trials.
40mg/16mg in 1 trial each.
Data from several trials could not be combined in a meta-analysis
- Different parameters (time of pain score, at rest/movement, unclear information from studies)
Primary outcome – Morphine 24h – (6 studies, 326 patients)
- 01mg in dex group (-5.01 to -3.01mg) I2=0%
- (not much difference omitting spinal bupivacaine & morphine, or using 40mg as dex dose)
- Risk of bias low
- Trial sequential analysis à sufficient evidence for primary outcome
- Leave-one-out meta-analysis à result not driven by one single trial
- GRADE evaluation à high level of evidence – further studies unlikely to change result
- Longer time to first analgesic request (86min later) – significant – but heterogeneity in this analysis was high I2=93%
- Other secondary outcomes – no significant difference
- Number of patients requiring rescue analgesia
- Previous meta-analysis of IV dex in GA à – 0.82/0.85mg post-op morphine with moderate/high doses of dex respectively
- No other analysis has found such a pronounced effect of dex
- One trial with intrathecal morphine – no significant difference of dex on opioid consumption
- Suggests 8mg of dex as ideal dose
- Interesting question
- Publications in last 10 years – contemporary clinical practice
- Easy intervention
- Confusing inclusions/exclusions of studies
- High heterogeneity for “time to first analgesic requests”
- ? Confounding factor of PCA
- VAS scoring timing/at rest/movement
- ? Side effect profile of dex – infrequent reporting wound infection/healing (Cochrane 2018 – single dose does not affect risk of infections, no definite conclusions for delayed wound healing)
- ? Other side effects of dex not mentioned – such as glucose
- High level of evidence that IV dexamethasone improves post-op analgesia after spinal anaesthesia
- Reduces 24h morphine equivalent consumption
- Prolonging time to first analgesic request
Discussion during Journal Club
- Noted that there was a mix of surgical procedures in the meta-analysis – should not mix LSCS/obstetrics with other patients. Hernia operations are not that painful so should not mix with operations after which we normally expect a lot more pain.
- What do people give dexamethasone for? Most at JC are giving it for PONV – is it useful for N&V though and is it the correct dose (see previous JC)? Potentially should be using other N&V drugs?
- Does 4mg IV morphine really make that much difference? Would it make a difference to the opioid side effect profile?
- Does it make a difference when the first request of analgesia is? – Perhaps should have looked at overall opioid consumption
- What is the side effect profile of even a single shot of dexamethasone? Does this need to be considered as well as thinking about decreasing opioid consumption?
- At Kingston we use long acting opioids for LSCS spinals, and for #NOF often a nerve block as well, so IV dexamethasone may not add that much to our practice here.
Summary by Dr PY Kuo. Journal Club Meeting 18th July 2019.
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