This prospective observational study aims to evaluate the impact of epidural catheter placement techniques - loss of resistance (LOR) and hanging drop (HD) - on first-attempt success rates and procedural complications among anesthesia residents. Residents with at least two years of training will perform epidural catheterization under supervision for patients scheduled for elective surgery requiring perioperative epidural analgesia. An independent observer will record procedural details, complications, and postoperative pain scores. The study will enroll 440 patients aged 18-80 with ASA I-III classification.
Epidural catheterization is a cornerstone technique in perioperative and obstetric pain management. Two established methods are commonly used to identify the epidural space: the loss of resistance (LOR) technique, using air or normal saline, and the hanging drop (HD) technique. Although both are widely employed, comparative data on their performance by residents in training are limited. This study prospectively observes which technique the resident chooses, records procedural parameters (depth of epidural space, number of attempts, level of insertion), and documents immediate complications (dural puncture, intravascular placement, paresthesia, hypotension) and postoperative outcomes (NRS scores at 0, 6, 12, and 24 hours; PDPH). Cases in which a resident is unable to complete the procedure are documented separately, including the reason for failure and subsequent management by a supervising specialist. All procedures are performed using an 18G Tuohy needle and standard catheter set. A test dose is administered to all patients following catheter placement. Data are recorded by an independent observer using a standardized data collection form.
Study Type
OBSERVATIONAL
Enrollment
440
Epidural catheterization performed using an 18G Tuohy needle and standard catheter set by anesthesia residents with a minimum of two years of training, under specialist supervision. Technique selection (LOR or HD) is at the discretion of the performing resident and is not randomized.
Marmara University Pendik Training and Research Hospital
Istanbul, Maltepe, Turkey (Türkiye)
First-attempt success rate
Defined as successful epidural space identification and catheter placement in a single Tuohy needle insertion attempt, without redirecting the needle.
Time frame: Time Frame: Immediately upon procedure completion
Dural puncture rate
Inadvertent dural puncture defined as free flow of cerebrospinal fluid through the Tuohy needle or epidural catheter, confirmed by visual inspection. Recorded as yes/no by the independent observer at the time of the procedure
Time frame: Intraoperative
Catheter Advancement Failure Rate
Inability to thread the epidural catheter beyond 3 cm into the epidural space despite confirmed needle placement, necessitating needle repositioning or procedure abandonment. Recorded as yes/no by the independent observer.
Time frame: intraoperative
Operator-Assessed Difficulty Score
The performing resident rates the overall technical difficulty of the procedure immediately upon completion using a 5-point Likert scale: 1 = very easy, 2 = easy, 3 = moderate, 4 = difficult, 5 = very difficult. Recorded on the standardized data collection form
Time frame: Immediately after procedure completion
Intravascular catheter placement rate
Unintentional intravascular placement defined as aspiration of blood through the epidural catheter prior to test dose administration. Recorded as yes/no by the independent observer immediately following catheter advancement
Time frame: intraoperative
Postoperative Pain Scores
Pain intensity assessed using the Numerical Rating Scale (NRS), where 0 = no pain and 10 = worst imaginable pain. Recorded at four time points: immediately upon arrival to the recovery unit (0 hours), and at 6, 12, and 24 hours postoperatively by the independent observer.
Time frame: 0, 6, 12, and 24 hours postoperatively
Rate and Type of Assistance Required During Catheter Placement
The level of assistance received by the performing resident is recorded in three categories: (1) No assistance - procedure completed independently; (2) Verbal guidance only - supervising specialist provides verbal instructions without physical intervention; (3) Physical assistance - supervising specialist takes over needle or catheter manipulation partially or completely. Recorded by the independent observer at the time of the procedure.
Time frame: Intraoperative
First-Attempt Success Rate Stratified by Resident Seniority Level
First-attempt success rates are compared across three seniority strata defined by duration of anesthesia training: junior residents (2-3 years), intermediate residents (3-4 years), and senior residents (4 years and above). Seniority is determined by the total duration of anesthesia specialty training at the time of the procedure.
Time frame: Intraoperative
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