Evaluation of Addition of Dexamethasone to Transversus Abdominis Plane (TAP) Peripheral Nerve Block

Evaluation of Addition of Dexamethasone to Transversus Abdominis Plane (TAP) Peripheral Nerve Block: Does it Enhance the Quality and Duration of Analgesia?

Transversus abdominis plane (TAP) blocks are increasingly being performed after abdominal surgery to provide post operative analgesia. Dexamethasone has demonstrated an ability to prolong the effective duration of analgesia in several different peripheral nerve blocks. The study will examine, in a blinded, prospective and randomized fashion, whether the addition of dexamethasone to TAP blocks similarly prolongs blockade and pain relief. The study will compare local anesthetic with and without the addition of dexamethasone in the TAP block.

The study will be done in two phases. In the first phase, patients will be randomized to receive either 20 cc of 0.125% bupivicaine with or without 2 mg of dexamethasone on each side of their abdomen (40 cc and 4 mg in total) and patients who receive the dexamethasone will be compared with patients who did not receive it. In the second phase, we will assess whether patients can serve as their own controls by adding dexamethasone only to one side of the block (one side of the abdomen) and comparing pain relief/efficacy with the contra-lateral plain local anesthetic effect. The study will assess pain relief, opioid consumption, level of blockade, and operator's prospective assessment of likely efficacy, based on the ultrasound visualization of the local anesthetic injection as compared with actual efficacy.

Inclusion Criteria:

• Male patients, between ages 18-85 years old, undergoing Robot-assisted laparoscopic prostatectomy by a single surgeon at a single hospital.
• Subjects are physically and mentally able to participate in the study.
• Subjects are able to give fully informed consent to participating in this study after demonstrating good understanding of the risks and benefits of the proposed components of the TAP block.

Exclusion Criteria:

• Demonstrated hypersensitivity or allergy to local anesthetics or dexamethasone.
• Any subject whose anatomy, or surgical procedure, in the opinion of the investigator, might preclude the potential successful performance of a TAP block.
• Any subject, who in the opinion of the investigator, might be harmed or be a poor candidate for participation in the study.