Serum Ropivacaine Concentrations in Pediatric Patients Receiving Continuous Wound Catheter Analgesia
Condition: Alveolar Bone Grafting; Alveolar Cleft Grafting
Study type: Observational

Summary: 
      The primary investigators in this study plan to investigate serum concentrations of
      ropivacaine in pediatric patients who already receive as standard of care a continuous wound
      catheter after an iliac crest alveolar bone graft harvest for completion of a previous cleft
      palate repair.

      The goals of this study are 1) to determine serum concentrations (free, unbound) of
      ropivacaine 2) To evaluate pain scores during the perioperative period to determine efficacy
      of wound catheters for postoperative analgesia for iliac crest bone graft harvest.
    

Detailed description: 
      There have been numerous investigations of serum concentration of ropivicaine using wound
      catheters in adults. These studies have revealed that wound catheters provide effective
      analgesia without toxic levels of serum ropivicaine. Our current proposal is different for
      two reasons. One, the investigators will be investigating the serum levels of ropivacaine in
      pediatric patients. There are currently no studies investigating the efficacy of this
      technique in the pediatric population. Two, the wound catheter currently being placed by Dr
      Losee (and plastic surgeons in other pediatric centers) as part of standard of care is
      different from other wound catheters. Most wound catheters described in the literature are
      placed in the surgical wound between muscle and facial planes. The catheter placed by Dr
      Losee for his routine postoperative pain control is placed adjacent to the periosteum and
      adjacent to the bone harvest site. Dr Losee has been performing this technique as part of
      standard patient care and it appears to provide excellent analgesia without side effects from
      the ropivacaine. However, it is unknown what effect this location has on serum plasma levels
      of ropivacaine. Measuring unbound ropivacaine will help define whether or not these wound
      catheters maintain the serum ropivacaine levels below, near, or above toxic levels. Pediatric
      studies have investigated the serum ropivacaine levels during epidural infusions and
      peripheral nerve blocks. This local anesthetic is safe as long as the administration is
      limited to weight based limits. For continuous infusions, ropivacaine should not be
      administered at a greater rate than 0.4 -0.5 mg/kg/hr. The wound catheters for The Childrens
      Hospital of Pittsburgh Plastic Surgery service are administered at 0.25 mg/kg/hr. Ropivacaine
      is the local anesthetic of choice for many pediatric hospitals and for the Acute
      Interventional Pediatric Pain Service at the Children's Hospital of Pittsburgh because it
      appears to have a slight safety advantage over bupivacaine. Ropivacaine does not bind sodium
      channels as avidly as bupivacaine and therefore may not be as cadiac toxic. However, the
      location of the catheter can alter absorption and may alter plasma levels. Currently there is
      no data for pediatric iliac crest wound catheters. Since this technique is already a standard
      of care here at this center, we plan to measure serum ropivacaine levels to define these
      values.

      It is important to understand the dosages currently being used in this pediatric population
      and the effects on serum local anesthetic levels. When local anesthetic is infused through an
      epidural, peripheral nerve block, or wound catheter, there is an elevation in local
      anesthetic plasma levels in the patient. The plasma levels depend on the dose, concentration
      and location of the catheter. Current literature has defined the plasma levels obtained
      during continuous infusions of local anesthetic through wound catheters in adults. Safe
      infusion rates have been defined for adult catheters. This data does not exist for wound
      catheters in pediatric patients and this study will begin to define these limits. In
      particular, the catheter currently being placed as standard of care at The Children's
      Hospital of Pittsburgh is periostial and it is unknown what effect this location has on serum
      ropivacaine levels
    

Intervention name(s): ropivicaine
Intervention type(s): Procedure
Intervention description(s): Blood draws to measure serum ropivicaine
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Pediatric patients that require an iliac crest bone harvest that requires an iliac crest
        wound catheter