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Three Part Question

In [adults undergoing ESWL for renal stones] are [opiates] the most effective analgesics in [achieving pain control]

Clinical Scenario

A young adult with kidney stones amenable to extracorporeal shock wave lithotripsy (ESWL) attends for their first session of treatment and you wonder whether such patients should routinely be given opioid analgesia.

Search Strategy

Medline and EMBASE 1966-06/02 using the OVID interface.
[{renal stones OR renal calculi.mp} AND {analgesia OR opiates.mp} AND {lithotripsy}] LIMIT to English

Search Outcome

49 results of which 3 were relevant and included.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Parkin et al 2002 United Kingdom	64 patients attending for first treatment lithotripsy for kidney stones. 34 - Given Diclofenac (100mg PR) alone GROUP A 30 - Diclofenac (100mg PR) and Alfentanil via PCA GROUP B Exclusion criteria - NSAID allergy, concurrent analgesia, previous lithotripsy and inability to consent or use PCA.	Prospective Randomised Controlled Trial	Visual Analogue Score (VAS) 1-10 about maximum pain experienced during procedure and satisfaction with treatment 1-10 asked immediately after the procedure.	No difference in mean pain score between Group A and Group B 3.54 to 2.93 P=0.34 respectively. Satisfaction score significantly higher in PCA group 7.72 to 9.14 p = 0.04. No signifcant side effects reported in any patients.	Open to expectation bias in PCA group. Unclear whether power of study sufficient to detect a difference in pain score. Influence of variation in stone location along urinary tract not analysed.
Hector et al 2005 The Netherlands	200 patients undergoing Extracorporeal Shock Wave Lithotripsy(ESWL) for Kidney stones. ASA score I - II aged 18-80y/o. 100 - 0.05mcg/kg/min infusion of remifentanil Group 1 100 - 0.1mcg/kg/min infusion of remifentanil Group 2	Double Blind Randomised Controlled Trial	PCA demand frequency and actual boluses delivered. Visual Analogue Score (VAS) 1-10 of pain pre-op, immediately postop and 30 mins post-op. Post treatment nausea and vomiting, dizziness, itching, agitation and respiratory depression.	No significant difference in VAS Score with P<0.05. Reduced nausea and vomiting, dizziness and itch in lower dose group.	No control to establish role of remifentanil as drug of choice over other analgesics. No quantification of satisfaction of analgesic effect but just pain scores without context.
Schelling et al 1996 Germany	44 patients aged 18 or over attending for first session of Extracorporeal Shock Wave Lithotripsy for calculi in renal pelvis. 22 - Alfentanil infusion titrated by Anaesthesiologist GROUP 1 22 - Alfentanil administered by PCA GROUP 2 Exclusion criteria - alcohol abuse, chronic pain, opioids in last 7 days.	Prospective Randomised Controlled Trial.	Infusion rate of alfentanil required for tolerance of shock waves. Number of attempts and number of actual deliveries in PCA group. Total amount of alfentanil required in both groups. Pain severity at 10 minute intervals during treatment on a verbal rating scale 0-5. Level of sedation on a scale 0-5 at 10 minute intervals during procedure. Tolerance to procedure asked 24 hours afterwards.	No statistical difference between groups for pain and tolerance. PCA patients required fewer shock waves but no difference in total energy as tolerated higher discharge voltages. PCA group required significantly less drug 0.83 +/- 0.67mg vs 2.2 +/- 0.92mg P = 0.006 No adverse effects observed in any patient.	Unvalidated method of pain scoring and tolerance scoring.

Comment(s)

The use of Extracorporeal Shock Wave Lithotripsy (ESWL) for treatment of kidney stones is well established. The principle of the technique is the acoustic shock wave destruction of the stone into fragments which may be excreted. The treatment can be associated with significant pain. The procedure is generally limited to the out-patient setting and so choice of analgesic is limited to those that provide rapid recovery. Different centres have differing analgesic regimes with no current consensus on an optimum regime.

Clinical Bottom Line

The use of an NSAID such as Diclofenac in combination with an opiate such as alfentanil may not significantly improve absolute analgesic level however does improve satisfaction to treatment. If an opiate is considered administration via a PCA rather than continous infusion will offer equal analgesia with reduced total amount of drug needed.

References

1. Parkin et al Analgesia for Shock Wave Lithotripsy Journal of Urology Apr 2002 167(4):1613-1615
2. Hector et al Remifentanil as a Single Drug for ExtracorporealShock Wave Lithotripsy: A Comparison of Infusion Doses in Terms of Analgesic Potency and Side Effects Anaesthesia and Analgesia Aug 2005 101(2):365-370
3. Schelling et al Patient Controlled Analgesia for Shock Wave Lithotripsy: The Effect of Self-Administered Alfentanil on Pain Intensity and Drug Requirement Journal of Urology Jan 1996 155(1):43-47