Anesthesiology, Article

Feasibility and initial experience with continuous nerve blocks by emergency physicians

a b s t r a c t

Introduction: Peripheral nerve blocks and Regional anesthesia are routinely used to alleviate pain in the emer- gency department. Our objective is to report on the feasibility and initial experience of emergency physicians ini- tiating and managing continuous nerve blocks for trauma patients.

Methods: This was a retrospective, observational cohort study of a convenience sample of patients 18 years or older presenting with either rib or Hip fractures between August 15, 2016 and January 15, 2019. Demographic and clinical data was abstracted using a structured data collection form. Data collected included basic demo- graphics, mechanism of injury, type of regional anesthesia, admission location, Respiratory complications, pre- and post-procedure opioid use, efficacy of anesthesia and duration of continuous nerve blockade. All analyses were descriptive in nature, including means, median, and range when appropriate.

Results: Forty-one patients presented during the study period with rib or Hip fractures and received a nerve block catheter and a continuous infusion pump. The mean age of patients was 65.9 years and 26 (63.4%) patients were male. The mean duration of continuous nerve blockade was 3.4 days (range 1-9 days). Hourly opioid use was re- duced by 58%. The most common complication was accidental dislodgement of the catheter;, no patient devel- oped a pneumothorax, hemothorax, catheter related infection, or hematoma.

Conclusions: It is feasible and effective for emergency physicians to initiate and manage continuous nerve block- ade for acute hip and rib fractures. Continuous nerve blockade may allow trauma patients to significantly de- crease their use of opioids.

(C) 2020

Introduction

Emergency physicians (EPs) routinely manage acutely painful con- ditions. More recently, we have also been tasked with limiting the use of opioids. For many traumatic conditions, opioids are considered the mainstay of therapy. peripheral nerve blocks and regional anesthesia are commonly used in emergency medicine, to improve pain control and decrease the use of opioids in the acute setting [1].

After several years of using single-shot nerve blocks, we realized that continuous nerve blockade would be even more beneficial to our pa- tients. Based on our experience and our patient population we decided to begin offering continuous nerve blocks for our patients with rib and hip fractures. Rib and hip fractures are common injuries in all emer- gency departments (ED), and even more prevalent in our practice set- ting at a Level 1 Trauma Center.

Aggressive analgesia is important for patients with both hip and rib fractures. Patients with hip fractures require pain control before and im- mediately following definitive care in the operating room, and rib

* Corresponding author.

E-mail address: [email protected] (M.L. Martel).

fractures typically require many days of pain control with a focus on avoiding pulmonary complications. Parenteral opioids are frequently employed as the initial strategy for these extremely painful conditions, but are associated with an increased risk of nausea, vomiting, delirium and decreased respiratory drive [2].

The two primary blocks that we performed were the fascia iliaca compartment (plane) block for patients with hip fractures and the Serratus anterior plane block for patients with rib fractures. The fascial iliaca plane block is a regional anesthesia block in which a large volume (20-60 cc) of dilute local anesthetic is injected into the fascial plane under the iliacus muscle to reach the femoral, and occasionally the lat- eral femoral cutaneous nerves. This provides regional anesthesia for painful conditions involving the hip and knee [3]. The serratus anterior plane block is a modification of the interfascial block of the thorax. A large volume (60-80 mL) of dilute local anesthetic is injected into the fascial plane between the serratus anterior and latissimus dorsi, mus- cles. In this plane the anesthetic readily spreads and effects the intercos- tal nerves which innervate much of the lateral chest wall [4]. This is a good alternative to more complex and dangerous thoracic blocks such as epidurals and paravertebrals. When placed with real-time ultrasound guidance the fascia iliaca and serratus anterior plane blocks are simple, safe, and effective.

https://doi.org/10.1016/j.ajem.2020.02.038

0735-6757/(C) 2020

Our goal is to report on the feasibility and initial experience of EPs placing nerve block catheters and using continuous infusion pumps to provide continuous fascia iliaca and serratus anterior plane blocks in trauma patients.

Methods

This was a retrospective, observational cohort study of a conve- nience sample of patients presenting with either rib or hip fractures be- tween August 15, 2016 and January 15, 2019. This study was approved by the institutional review board.

The study was performed at our tertiary-care, county ED with an an- nual census of approximately 110,000 visits. Our hospital is designated a Level 1 Trauma Center by the American College of Surgeons.

Subjects 18 years or older were identified for inclusion in this study if they had received regional anesthesia for hip or rib fractures. Trauma patients were identified as candidates for continuous regional anesthe- sia by one of the authors (MM, MR and RR) in the ED prior to admission. Patients were tracked through an ED database that includes all patients receiving these interventions. Patients b18 years old, pregnant patients and prisoners were excluded from the analysis.

We did not identify any absolute contraindications to the placement of a regional anesthesia catheter except an allergy to ropivacaine. Anticoagulation was not considered a contraindication to performing these plane blocks, unlike blocks in the epidural space. However, pa- tients who were supratherapeutic were usually reversed prior to cathe- ter placement.

Demographic and clinical data was obtained by a trained abstractor (JM) using a structured data collection form. Six randomly selected charts were also reviewed by a principle investigator (MM). Data collected included basic demographics, mechanism of injury, co-

morbidities, admission diagnosis, type of regional anesthesia, admission location, respiratory complications, respiratory interventions, proce- dural and anesthetic complications, pre- and post-procedure opioid use, efficacy of anesthesia and duration of catheter placement. All anal- yses were descriptive in nature, including means, median, and range when appropriate. Data analysis was performed in Excel (Excel version 1812; Microsoft, Redmond, WA).

Methods Procedure conditions

Patients were considered potential candidates for continuous re- gional anesthesia based on inadequate pain control with oral or paren- teral medications. Real-time ultrasound with a high-resolution linear transducer was used to perform all procedures. Although both catheters can be placed with patients in the supine position, the serratus anterior plane block is ideally placed with the patient in the decubitus position with the injured side up. Most catheters were placed in the ED but some were placed after admission on the hospital floor. An assistant is not essential, but very helpful for sterile preparation, injection, and hydrodissection during the procedure.

Methods Catheter placement procedure

We perform all regional anesthesia using ultrasound guidance. A Mindray TE7 ultrasound machine (Mindray North America, Mahwah, New Jersey) equipped with a high-resolution Linear probe was used most commonly for the procedures.

Once a patient was identified for continuous regional anesthesia, in- formed consent was obtained. The area of interest was sterilely pre- pared and draped. With the patient in a supine position, the anatomy of the area for the Serratus anterior block is made up superiorly by the

Serratus Anterior Plane

Serratus Anterior Muscle

Rib

Lattisimus Dorsi Muscle

Fig. 1. Longitudinal view in the mid-axillary plane for the serratus anterior plane block.

apex of the axilla, posterior to the pectoralis muscles and anterior to the latissimus dorsi. The plane for injection is immediately overlying the serratus muscle at the level of the fifth rib in the mid axillary line. The initial injection into the plane was approximately 3 mg/kg of ropivacaine diluted with normal saline, for a total volume for injec- tion of 60-80 mL. Fig. 1 is a typical ultrasound image of the region of catheter placement between the Serratus Anterior and latissus dorsi muscles. Real-time ultrasound guidance was used in all cases. The potential space between the two muscles was opened using hydrodissection, then the catheter was advanced approximately 2-4 cm into the space and the remainder of the initial bolus was injected through the catheter. Fig. 1 depicts the ultrasound image that will be visualized.

The fascia iliaca block was performed in the supra-inguinal region. The patient was positioned supine with the affected leg held extended with slight internal rotation. At the level of the anterior superior iliac spine the transducer was aligned perpendicular to the inguinal ligament (with the transducer marker toward the umbilicus) and the fascia iliaca is visualized between the iliacus and sartorius muscles (Fig. 2.). The nee- dle and catheter were advanced in-plane and only when the needle tip was well visualized, since the needle path is toward the peritoneum. Hydrodissection was used to open up the potential space between the Sartorius and iliacus muscles, and then the catheter was advanced 2-4 cm into the space and the remainder of the bolus was injected through the catheter. The initial bolus for this block was also 3 mg/kg of ropivacaine diluted in saline, for total volume for injection of 60-80 mL.

For each block type, an ON-Q prep tray (Avanos Medical, Inc., Alpha-

retta, Georgia) and 4- or 6-inch. ON-Q Quickbloc catheter (Avanos Med- ical Inc., Alpharetta, Georgia) was used based on the patient’s body habitus and desired location for securement of the catheter hub.

Catheters were then secured in place using the proprietary catheter holder, benzoin and transparent adhesive dressings.

Methods Infusion

The ON-Q Pump with Select-A-Flow (Avanos Medical, Inc., Alpha- retta, Georgia) system was used for the continuous infusion of local an- esthetic. Ropivicaine was the local anesthetic employed for all regional anesthesia patients. The 600 mL ON-Q pump was overfilled according to manufacturer instructions to 750 ml with 1500 mg of ropivacaine (300 ml of 5 mg/ml) and 450 ml sterile normal saline.

infusion rates vary based on several factors. The Select-A-Flow sys- tem infuses at rates between 2 ml/h and 14 ml/h in increments of 2 ml/h. For the Erector spinae plane block, the majority of patients re- quire the maximum rate, 14 ml (28 mg)/h. Typical fascia iliaca plane blocks require infusion rates between 8 and 14 ml/h. The maximum in- fusion rates of ropivacaine should not exceed 28 mg/hr.

According to our institutional guidelines, nursing interaction with the infusion pumps is limited. Nursing staff monitor the catheter site for signs of infection and evidence of catheter migration. Daily flushing of the catheters, pump adjustments, redressing or catheter manipula- tion was performed by the physicians.

Monitoring protocols

Patients were admitted to various Levels of care based on individual monitoring requirements. cardiac monitoring was not a prerequisite for patients with regional anesthesia. Our ED based regional anesthesia team was a consulting service for admitted patients. General monitoring instructions are provided in Fig. 3.

Iliacus Muscle

Sartorius Muscle

Anterior Superior Iliac Spine

Fascia Iliaca Plane

Fig. 2. Ultrasound view of the supra-inguinal approach to the fascia iliaca plane block.

The patient had a regional anesthesia catheter placed for management of pain related to ***.

General guidelines for care of the catheter, patient assessment and local anesthetic dosing/toxicity are outlined below.

insertion site assessment:

Upon arrival and every 4 hours until catheter is removed.

Notify the physician on-call for signs of redness, swelling or pain at the catheter insertion site.

pain assessment:

Upon arrival and every 4 hours.

PRN with additional Pain interventions.

Peripheral nerve catheter and dressing care:

Patients cannot shower or bathe while the catheter is in place.

Patients with lower extremity blocks must have assistance with ambulation (if applicable) when an infusion is running to prevent catheter dislodgement and falls due to Extremity weakness.

Inspect dressing on every shift and after activity for integrity and drainage. Some leakage around the catheter insertion site is expected.

  • Dressings may be reinforced as needed, using sterile technique.
  • Ensure insertion site remains viable.

If catheter becomes dislodged, notify the on-call physician.

If catheter becomes disconnected from the pump tubing, tape a sterile guaze pad to the end of the catheter and notify the on-call physician.

The patient must always have patent Intravenous access.

A sign must be placed on patient’s head of bed indicating a peripheral nerve block is in place.

The blocked extremity must be protected from injury, including extreme temperature, pressure, sharp objects and excessive traction.

Sensory / Motor function assessment:

Upon arrival and 4 hours until block resolves completely.

If profound motor block of either lower extremity, notify the on-call physician.

If patient with lower extremity block above T10 (umbilicus), notify the on-call physician.

If patient with a paravertebral block has bilateral sensory block above T4, notify the on-call physician.

Ropivicaine Dosing Guidelines

For boluses we use 0.5% ropivacaine (30 mL per bottle) For continuous infusion we use 0.2% ropivacaine

patient weight Max Bolus Dose of 0.5% (3 mg/kg) Max Continuous Infusion Rate of 0.2%

40 kg

24 mL

10 mL

50 kg

30 mL

12 mL

56 Kg

33 mL

14 mL

60 kg

36 mL

14 mL

70 kg

42 mL

14 mL

80 kg

48 mL

14 mL

90 kg

54 mL

14 mL

95 kg (209lbs)

57 mL

14 mL

100 kg or more

60 mL

14 mL

Nerve block and local anesthetic complications and side effects:

Immediate complications include pain or discomfort, block failure, vascular puncture, hematoma formation, nerve damage, allergic reaction, and Local anesthetic toxicity.

Delayed complications include infection, nerve toxicity, and permanent nerve injury.

Local anesthetic toxicity may occur if local anesthetic is injected directly into a blood vessel or from vascular absorption over time.

Signs and symptoms of local anesthetic toxicity include drowsiness, numbness or tingling of the tongue/mouth, tinnitus, Visual disturbances, generalized muscle twitching, unconsciousness or Seizure activity, respiratory arrest and cardiac arrest.

The on-call physician should be notified if any complications or toxicity is suspected.

Anticoagulation management:

Placement of a peripheral nerve catheter in an Anticoagulated patient is at the discretion of the Physician. risks and benefits of placement must be weighed in this setting.

Anticoagulation with subcutaneous unfractionated heparin and once Daily dosing of Low Molecular Weight Heparin is acceptable while the peripheral nerve catheter is indwelling.

At the discretion of the physician, prior to removal of the catheter:

  • Consider holding Low Molecular Weight Heparin for 12 hours.
  • Hold intravenous (IV) heparin infusions for 2 hours.
  • No additional precautions are necessary with the use of subcutaneous unfractionated heparin.

Notify the on-call physician and stop the infusion pump if: Acute changes in patient status.

Excessive sedation or decrease in neurologic status.

Signs/symptoms of local anesthetic toxicity including numbness or tingling of tongue/mouth, tinnitus, visual disturbances, generalized muscle twitching, unconsciousness or seizure activity. Severe local anesthetic toxicity may progress to respiratory or cardiac arrest.

If severe local anesthetic toxicity is suspected, the on-call physician should be notified and intralipid infusion should be obtained from the pharmacy.

CLAMP CATHETER IF PATIENT BECOMES HYPOTENSIVE, HEMODYNAMICALLY UNSTABLE OR IF

CARDIAC ARREST OCCURS and notify the on-call physician immediately.

Discharge procedure

On discharge from the hospital, patients were given the option to be discharged with the regional anesthesia catheter in place. If they opted to continue treatment, they were instructed to keep the insertion site clean and dry. Patients were not allowed to shower or bathe while the catheter was in place.

Patients discharged home were instructed on proper use of the Select-A-Flow dial to allow up or down titration of the infusion rate based on the level of their pain. The manufacturer’s patient brochure was given to all patients, and they were directed to the myon-q.com website for general references. All patients were provided contact infor- mation for one of the authors (MM or RR) for any questions or concerns. Patients were instructed to return to the ED for pump replacement (up to a total catheter indwelling time of 7 days) and catheter removal. In this cohort, patients discharged to a subacute rehabilitation or long- term care facility had the catheters removed prior to discharge.

Theory

Patients with hip or rib fractures require aggressive pain control for both comfort as well as to reduce potential complications. Patients who receive continuous regional anesthesia for these painful conditions may require fewer opioid medications and have fewer complications as a re- sult of their injuries.

Results

We identified 41 patients who presented during the study period with hip or rib fractures who had a regional anesthesia catheter and a continuous infusion pump placed by EPs. During the study period, a total of 651 patients presented with a hip fracture and 1503 patients presented with at least one rib fracture. A total of six (15%) patient re- cords were concurrently reviewed. Weighting for dichotomous re- sponses, the cohen’s kappa coefficient for interrater reliability was calculated to be 0.92. The mean age of patients was 65.9 years and 26 (63.4%) patients were male. Additional patient characteristics are pre- sented in Table 1. The use of opioids before regional anesthesia is based on time spent in the ED, with a mean time in department of 6 h 31 min (range 36 min to 13 h 46 min). Opioid use after regional anes- thesia represents all opioid use while hospitalized with an indwelling catheter in situ. The mean duration of catheter placement was

3.4 days (range 1-9 days). Hourly opioid use was reduced by 58%; the mean Morphine equivalents received before catheter placement was

3.8 mg per hour and the mean morphine equivalents received after catheter placement was 1.6 mg per hour.

Patients were admitted to all areas of the hospital after the place- ment of the indwelling catheter with a continuous infusion pump. Twenty-five patients were admitted to a general unit, four with telem- etry, seven to an intermediate care unit and five to an intensive care set- ting. Eight patients were discharged from the hospital with a catheter in place and instructed to return for removal on catheter day seven. The catheters were removed by physicians (31), registered nurses (1), ad- vanced practice providers (1) or patients (5), and four catheter re- movals were not recorded in the medical record. Table 2 depicts the complications potentially related to regional anesthesia, to the local an- esthetic ropivacaine, or the indwelling catheter.

Discussion

Patients with hip and rib fractures are frequently seen in the ED and usually require significant analgesia. More than 300,000 patients re- quire hospitalization for hip fractures annually in the United States [5].

Table 1

Characteristics of the 41 patients with rib or hip fractures who received regional anesthe- sia for pain control

Patient demographics

Age (mean years) 65.9 (range 28-94)

Male 26 (63%)

Weight (mean kilograms) 82.6 (range 46.7-142)

Current smoker 15

Ethnicity

White 34

Black 4

Asian 1

Native American 2

Mechanism of injury

Motor vehicle collision 4

Fall 30

Assault 1

motorcycle crash 4

Tractor accident 2

Co-morbid conditions

Asthma 2

COPD 5

CHF 3

CAD 7

ESRD 2

Other cardiac/Pulmonary 18

Type of regional anesthesia performed

Serratus anterior plane block 27

Fascia iliaca compartment block 13

Intercostal nerve block 1

Indwelling catheter placed 39

Type of catheter and location

Quick bloc fascia iliaca 13

Quick bloc serratus anterior 27

On-Q silver soaker intercostal 1

Rib fractures are even more common, and our institution alone admits

N300 patients annually for the management of rib fractures.

In our ED we traditionally used single-shot nerve blocks as an ad- junct to opioids in patients with rib and hip fractures. In 2016 we began using over-the-needle catheters and auto-infusing elasto- meric pumps to provide continuous nerve blocks in these patients. We learned to place regional anesthesia catheters during a four- hour cadaver training session. We developed institutional protocols with our trauma and Orthopedic surgeons, as well as guidelines for safe ropivacaine dosing. The majority of catheters were placed by one of the authors of this study (RR and MM), but a total of six differ- ent EPs placed at least one catheter. Many catheters remained in place for up to one week, and several patients were discharged with the systems in place.

Our findings show that EPs can progress from placing single shot nerve blocks to providing continuous regional anesthesia with little additional training. Nerve blocks are part of the core curriculum in emergency medicine residency programs, and in recent years most pro- grams teach Ultrasound-guided nerve blocks. Therefore, we believe that the majority of practicing EPs, and especially recent residency gradu- ates, could realistically learn this procedure.

Although this was not a randomized controlled study, we found that hourly Opioid requirements were markedly decreased after continuous anesthesia was initiated. The incidence of complications was very low. No patient developed a pneumothorax, hemothorax, catheter related infection, or hematoma. It was noted that some patients had inadequate anesthesia with continuous anesthesia infusions, despite good pain re- lief with the initial large volume injection. This phenomenon was likely due to the fact that success of fascial plane blocks is often volume de- pendent. In most cases, Bolus infusions of either saline or ropivacaine improved the effect of anesthesia.

Fig. 3. General monitoring guidelines for continuous nerve blockade.

Table 2

specific complications experienced by patients

Type of complication Number of

patients

Hypoxia (b92%) at any time? 18

Required supplemental oxygen 23

Bilevel positive airway pressure 3

Endotracheal intubation 2

Concerns about ropivacaine toxicity? 4

Confusion 3

Paresthesia 0

Seizure 0

Arrythmia (ultimately NOT attributed to ropivicaine toxicity) 2

Developed pneumonia? 4

Patients with serratus plane block 2

Patients with fascia iliaca block 2

Catheter related infection 0

Catheter associated hematoma 0

Inadequate initial anesthesia 0

Pneumothorax/Hemothorax 0

Accidental dislodgement or removal of catheter 7

Acute confusion was noted in three patients and appeared to im- prove with holding the infusion for several hours and restarting it at a lower rate. It is unclear if these symptoms were related to ropivacaine toxicity; these patients were elderly and at high risk for hospital- induced delirium and confusion is not usually associated with continu- ous ropivacaine infusion [6]. Two patients were noted to have arrhyth- mias during the continuous infusion of the local anesthetic. One had atrial fibrillation and one had Sinus bradycardia. Neither events were felt to be due to ropivacaine toxicity.

Hypoxia requiring supplemental oxygen was seen commonly. Eigh- teen patients were hypoxic at some point during their ED stay and hospitalization; 23 required supplemental oxygen. Two patients with a regional anesthesia catheter required endotracheal intubation. In retrospect, the intubated patients may not have been ideal candidates for the procedure based on poly-trauma and their high-risk initial presentations.

It is important to note that only five patients required intensive care unit placement during their hospitalization. Based on the average age of patients in the study, one might expect that more patients would re- quire this level of care. Equally significant, only four patients, two of whom had hip fractures, developed pneumonia at any time during their hospital course. Once again, given the age of the cohort, this small number of patients is notable.

Eight patients were discharged from the hospital with the indwell- ing catheters remaining in place. This suggests that in select patients, outpatient management from the ED is possible. These patients

returned to the ED for removal of the catheter, except for one patient who elected to remove his own catheter at home.

Conclusion

Based on our experience, it is feasible for EPs to initiate and manage continuous regional anesthesia using a simple over-the-needle catheter and an auto-infusing pump. Complications related to the procedure were uncommon, opioid requirements were reduced, and patient feed- back was overwhelmingly positive. More research is needed, but this appears to be a promising means of decreasing opioid use in trauma patients.

Funding sources

This research did not receive any specific grant from funding agen- cies in the public, commercial, or not-for-profit sectors.

CRediT authorship contribution statement

Marc L. Martel:Conceptualization, Methodology, Validation, Formal analysis, Investigation, Writing – original draft, Writing – review & editing, Supervision.Mark R. Robidoux:Conceptualization, Methodology, Formal analysis, Writing – original draft, Writing – review & editing.Jaleesa L. Morris:Formal analysis, Investigation, Writing – original draft, Writing – review & editing.Robert F. Reardon:Conceptualization, Methodology, Formal analysis, Investigation, Writing – original draft, Writing – review & editing, Supervision.

Acknowledgements

None.

References

  1. Brasel KJ, et al. Western trauma association critical decisions in trauma: management of rib fractures. J Trauma Acute Care Surg 2017;82(1):200-3.
  2. Chau DL, Walker V, Pai L, Cho LM. Opiates and elderly: use and side effects. Clin Interv

    Aging 2008;3:273-8.

    Foss NB, Kristensen BB, Bundgaard M, et al. Fascia iliaca compartment blockade for Acute pain control in hip fracture patients: a randomized, placebo-controlled trial. An- esthesiology 2007;106(4):773-8.

  3. Durant E, et al. Ultrasound-guided serratus plane block for ED rib fracture pain con- trol. Am J Emerg Med 2017;35(1):197-e3.
  4. Centers for Disease Control and Prevention. https://www.cdc.gov/ homeandrecreationalsafety/falls/adulthipfx.html, Accessed date: 24 June 2019.
  5. US Food and Drug Administration. Accessed June 24, 2019 https://www.accessdata. fda.gov/drugsatfda_docs/label/2006/020533s014lbl.pdf.

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