Interscalene Nerve Block vs. Sedation for Shoulder Dislocation Reduction

US Guided Interscalene Block Compared With Sedation for Shoulder Dislocation Reduction in the ER

Shoulder dislocation is the most common joint dislocation presented to the emergency room (ER) and reduction by medical team is always needed. Shoulder dislocation and reduction are often very painful and require some form of sedation, pain relief and muscle relaxation for reduction maneuvers. Several sedation protocols for reduction maneuver are described in the literature, and each institution is guided by its own protocol to optimize patient comfort and safety. At the Tel Aviv Medical Centre (TLVMC) ER sedation with ketamine and midazolam are the mainstay form of sedation for shoulder dislocation reduction.

Sedation is not without risk, it is time consuming for the medical staff, and need personal supervision. Sedation under busy ER conditions can cause a burden to the medical team which can end up in treatment insufficiency and patient safety failure.

Ultrasound (US) guided interscalene block (ISCB) for shoulder surgery was found to be an effective method for perioperative analgesia. However, there is limited data on performance of US guided ISCB for shoulder dislocation reduction and its comparison to other analgesic modalities Both techniques (block and sedation) for shoulder dislocation procedure are being performed for two years at the TLVMC, however no study was done to evaluate these two analgesic modalities.

The current study compares sedation vs. US guided ISCB for the treatment of shoulder dislocation in the ER at the TLVMC.

Study objective:

Comparison of two common analgesic methods, Sedation vs. US guided ISCB, for shoulder dislocation reduction in our institution.

Study design:

This is a prospective, randomized, interventional, open-label study with two arms- Sedation group and US guided ISCB group. The sedation will be conducted by the orthopedic surgeon who is certified to perform sedation and the US guided ISCB will be conducted by a certified anesthesiologist.

Primary outcome:

Time frame measured from the beginning of reduction procedure until readiness for dismissal from the ER according to the physician decision.

Secondary outcomes [short list]:

Visual Analogue Score (VAS), patient satisfaction, complications, US guided ISCB and sedation failure rate, overall reduction success rate, readmission rate to the ER, daily activity level measured by Quick DASH (Disabilities of Arm, Shoulder and Hand) outcome measure.

Shoulder dislocation is the most prevalent dislocation with a frequency of 0.5%-1.7% among the population, which requires reduction by medical staff in the emergency room (ER). Reduction procedure is often painful and require some level of sedation, analgesia, and muscle relaxation for its completeness. Several sedation protocols for reduction maneuver are described in the literature, and each institution is guided by its own protocol to optimize patient comfort and safety.

The literature describes multiple sedative agents such as Propofol, Etomidate, Midazolam, Fentanyl, etc. In the emergency department (ED) at Tel Aviv Medical Center (TLVMC), the sedation protocol contains Midazolam and Ketamine as the main sedative and analgesic agents.

Sedation is not without a risk. Known complications are respiratory depression, aspiration, and hemodynamic instability. These complications seem to be more prevalent in patients with decreased cardio-respiratory reserves, such as elderly, morbid obese, obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) patients.

In addition, sedation requires resources such a facility occupied with equipment for monitoring vitals, oxygen supply source, capnography and human resources including medical staff certified to provide sedation and handle any possible complication and nursing staff supervising the patient throughout the procedure from admission until release home from the ER.

The ED at the TLVMC is very active and busy throughout the day. Sedation under such condition create a real challenge for the medical team. This is translated into shortage in manpower and equipment availability and time needed to care for each patient. Such an atmosphere create huge burden on the medical team which can end up in treatment insufficiency and patient safety failure.

Recently, several new publications were published regarding the implementation of peripheral nerve block (PNB) under US guidance for analgesia and painful orthopedic procedure in the ER. Implementation of PNB for pain management in orthopedic procedures in the ER might constitute theoretical advantages over sedation.

Interscalene block (ISCB) is a very effective tool being used during shoulder surgery. However, there is limited data on performance of US guided ISCB for shoulder dislocation reduction and it's comparison with other analgesic modalities.Only one study to date compared sedation vs. US guided ISCB for shoulder dislocation reduction procedure in the ER. This study showed that patients who received ISCB had a shorter length of stay in the ER and required less supervision and medical intervention from the medical team.

Both US guided ISCB and sedation for shoulder dislocation procedure are being performed for a while at TLVMC. However no study was done to evaluate them and determine if one of the analgesic modality have any advantages over the other.

Objectives:

Comparison of two common analgesic methods, US guided ISCB vs.sedation, for shoulder dislocation reduction in the ER at the TLVMC.

Methods and Materials

Study Design:

This is a prospective, randomized, interventional non-blinded study with two arms- US guided ISCB group and Sedation group.

The sedation will be conducted by an orthopedic physician certified to perform sedation and the US guided ISCB will be conducted by an anesthesiologist who has at least one year of experience preforming regional anesthesia using US guidance.

Sample Size:

The study will include 70 subjects - 35 in each group. In order to compensate for dropouts we will aim for recruitment of 90 subjects.

Statistical Analysis:

Quantitative data with normal distribution will be evaluated using t-test for independent samples. In case the assumptions for parametric test will not hold true, quantitative data will be evaluated using an a- parametric Mann-Whitney test. Quantitative variables will be presented as mean and standard deviation.

Dichotomous data will be evaluated using chi-square test. Fischer exact test will be used when more than 20% of the expected observations were less than 5 or any expected observation was less than 2.

Categorical data will be presented as a number of cases and percent. Multivariate logistic regression analysis will be used for the primary outcome in order to determine independent risk factors. The data included in the multivariate logistic regression model will have a clinical significance according to the investigator clinical judgment and data found to have a Pv<0.1 in the univariate analysis. A Pv of 0.05 will be considered significant.

Inclusion Criteria:

1. Patients (ASA SCORE I-III) without acute cardio-pulmonary decompensation, who arrive to the ER with shoulder dislocation for reduction maneuver.

Exclusion Criteria:

1. Unconscious patient
2. Patient refusal/unable to give informed consent
3. Patients with acute cardio-pulmonary decompensation
4. Patients with known allergy to medications which will be included in the study
5. Patients who suffer additional injuries and need to be hospitalized for further treatment
6. Patients who received narcotic/sedative premedication before the procedure