Clinical trial NCT04196270: The Minimal Effective Volume (MEV90) of Ropivacaine 0.75% for Ultrasound-guided Transmuscular Quadratus Lumborum Block
Official title: The Minimal Effective Volume (MEV90) of Ropivacaine 0.75% for Ultrasound-guided Transmuscular Quadratus Lumborum Block for Unilateral Percutaneous Nephrolitotomy: a Study Protocol for a Dose Finding Trial
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: PHASE4
Conditions: Percutaneous Nephrolithotomy
Keywords: dose finding study
Lead sponsor: Zealand University Hospital
Sponsor class: OTHER
First posted: 2019-12-12
Enrollment: 40
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Intervention model: SEQUENTIAL
Intervention model description: The biased coin up-and-down sequential design (BCD) should be considered for direct determination of higher quantiles (ED90 and ED95) which provide useful clinical knowledge. The BCD was developed in the field of pharmacology and toxicology and was formulated by Durham et al. in 1997. In the BCD, volume assignment is carried out in a sequential and interactive method, which avoids that patients are randomized to doses with toxicity risk and seeks to concentrate treatments around the suitable doses.
Primary purpose: DIAGNOSTIC

Brief summary: This double-blind dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anesthetic administered to each patient depends on the response from the previous one. The TQL block is performed preoperatively, and the first patient recruited receives 20 mL of ropivacaine 0.75%. In case of block failure, the next patient will receive a higher volume (defined as the previous volume with an increment of 2 mL). Given a successful block for the first patient, the next patient will be randomized to either a lower volume (defined as the previous volume with a reduction of 2 mL) or the same volume as the previous patient. The respective probabilities being b=0.11 for a reduced volume and 1-b=0.89 for the same volume. Block success is defined as patient reported numeric rated scale (NRS) pain (NRS value ≤ 3 (0-10/10)), 30 minutes after arrival in the post anesthesia care unit (PACU). The NRS pain value is our primary and only outcome in the evaluation of the block. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV90 with narrow 95% confidence intervals derived by bootstrapping. Following inclusion of 25 patients early termination is considered when interim analysis shows sufficiently stabilization of MEV90 estimate. The final sample size is not known a priori, but a maximum of 40 patients will be enrolled in the trial.


Eligibility criteria: Inclusion Criteria:

* Patients eligible for the trail must comply with all of the following requirements to be included:

  * Scheduled for elective PNL surgery in general anesthesia with propofol and remifentanil
  * Age \> 18 years at the date of inclusion
  * Have received thorough information, oral and written, and signed the "informed consent" form on participation in the trail
  * ASA score 1-3

Exclusion Criteria:

* Inability to speak and understand Danish
* Allergy to local anesthetics or opioids
* Daily intake of opioids (evaluated by the investigators)
* Drug and/or substance abuse
* Local infection at the site of injection or systemic infection
* Difficult visualization of muscular and fascial structures necessary for successful block administration
* Pregnancy or breastfeeding

Primary outcomes:
measure: Numeric rated scale
timeFrame: 30 minutes after arrival in the post anesthesia care unit
Secondary outcomes:
Other outcomes:
Locations:
Study officials:
References: