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Changes In Urinary Substance P Level Is Correlated with Post-Operative Bladder Spasms Following Bladder Surgery

Sunday, October 21, 2012: 10:55 AM
Grand Ballroom B (Hilton Riverside)
Guilherme A. Rossini1, Brian M. Rosman1, Caio M. Oliveira1, Constance S. Houck2, Petra M. Meier2, Carlos Munoz-San Julian2, Sabrina T. Reis1, Carlo C. Passerotti3 and Hiep T. Nguyen1, (1)Urology, Children's Hospital Boston, Boston, MA, (2)Anesthesiology, Perioperative and Pain Medicine, Children's Hospital Boston, Boston, MA, (3)Urology, University Nove de Julho, São Paulo, Brazil

Purpose:

Children undergoing ureteral re-implantation surgery for vesicoureteral reflux (VUR) frequently experience post-operative bladder spasms. Substance P (SP) is a neuropeptide that is considered to be a major initiator of neurogenic inflammation and has been shown to have both sensory and efferent functions in the bladder. The aim of this study was to determine if changes in urinary SP are correlated with the severity of postoperative bladder spasms.

Material and Methods :

Patients older than 4 years of age undergoing bladder surgery were enrolled in this study after informed consent was obtained. Patients received a standard anesthetic and postoperative pain management regimen including caudal analgesia with bupivacaine and clonidine and round-the-clock IV ketorolac postoperatively. A urine sample was collected at the time of catheter placement (prior to incision) and set as the baseline. Additional urine samples were collected at 0.5, 1, 2, 6, 12, and 24 (if the catheter was still in place) hours after surgery from the Foley catheter and centrifuged and stored at -20 C until analysis. SP levels were analyzed via Parameter™ Substance P ELISA Assay. Pain was assessed via VAS or Face pain scale as soon as the patient was able to respond appropriately in the PACU, and repeated at 4, 8, 12 hours postoperatively, along with the character of the pain. For statistical analysis, pain scores were combined as mild (0-3), moderate (4-6) and severe (7-10).. Statistical analysis was performed with Chi-square and using SPSS ver. 20.0, and significance was set at p£0.05.

Results:

To date, 65 patients have been enrolled in the study, (54 female,11 male), with a mean age of 6.2(±1.5) years. Patients were categorized into two different groups according to the greatest change in SP relative to baseline. Group 1 (n=24) consisted of patients that had a change in urinary SP of <50% (above or below baseline), and patients in Group 2 (n=41) had a >50% change in SP relative to baseline. The majority (83.3%) of patients that had severe pain were in Group 2 (p=0.039) (Figure 1).

Conclusion: Our study demonstrates that patients that had the most change in urinary SP levels compared to baseline experienced more severe bladder spasms postoperatively. This suggests that urinary SP has the potential to serve as an effective biomarker for bladder spasm severity and could potentially be used to aid in both basic science and clinical studies evaluating the effectiveness of treatments for this type of spasmodic pain.

Table 1

 

Group 1

Group 2

p-value

Valium(mg)

*0.799

Mean

1.83

2.01

Morphine(mg) in PACU

*0.619

Mean

0.50

0.59

Morphine(mg) in floor

*0.544

Mean

2.26

2.74

Oxycodone(mg)

*0.301

Mean

1.81

2.50

*Chi-square

Figure-1

Paper_17700_abstract_15873_0.jpg