Difficulty in recruitment

This study intends to show the efficacy of remifentanil-dexmedetomidine infusions in combination with a caudal block for patients ages 1 year to 3 years old receiving elective surgery to investigate alternatives to the currently used volatile anesthetics.

In light of the concern for potential anesthetic neurotoxicity in infants and toddlers, it is prudent to start investigating alternative methods to decrease the amount of volatile anesthetic being utilized in this patient population. The US Food and Drug Administration has been asked to evaluate the data showing the neurotoxic effects of multiple anesthetic agents in animal models and humans. These studies have shown that N-methyl-D-aspartate (NMDA) receptor blockers such as ketamine,and gamma-Aminobutyric acid receptor (GABA) modulators like benzodiazepines, nitrous, propofol, barbiturates and isoflurane have been shown to cause brain cell apoptosis in animal models.

Regional anesthesia provides both intraoperative and postoperative analgesia may play a major role in effectively reducing the amount of general anesthetic used. Caudal anesthesia has been proven be both safe, effective and is applied widely in the pediatric population.

Dexmedetomidine is a selective alpha2-adrenergic agonist that acts in the brainstem by inhibiting norepinephrine release. Dexmedetomidine is commonly used off-label, including use for duration greater than 24 hours and any use in pediatrics. Dexmedetomidine has relatively few adverse events when compared to other sedative agents, with hypotension and bradycardia being most common.

Remifentanil has a rapid onset, rapid offset, small volume of distribution, rapid clearance, and a short elimination half-life, It may be a useful anesthetic for pediatric outpatient surgery.

While the current standard of care involves a volatile general anesthetic with a caudal block, anesthesiologists have alternative methods that can be utilized to allow an elective surgery to be performed. In summary, this study intends to show the efficacy and safety of a remifentanil-dexmedetomidine infusion and caudal block for patients ages 1 year-3 years old receiving elective circumcision, hydrocele repair, orchidopexy, mild hypospadias or inguinal hernia repair. This alternative anesthetic is already being studied in children under 12 months.

Inclusion Criteria:

• Children aged 1 - 3 years undergoing urologic surgery (circumcision, hydrocele repair, orchidopexy, mild hypospadias) or inguinal hernia repair
• American Society of Anesthesiologist Physical Status (ASA-PS) I or II
• Eligible for caudal block
• Parental/legal guardian consents for study '

Exclusion Criteria:

• Allergy to remifentanil, dexmedetomidine or ropivacaine
• Family history of malignant hyperthermia
• Parental/legal guardian refusal
• ASA-PS ≥ 3
• Symptoms of upper respiratory infection (URI) within the 2 weeks prior to surgery
• Known spinal deformity, presence of sacral dimple, or signs of infection at the site of the caudal block (e.g. diaper rash, skin redness or tenderness).