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| REVIEW ARTICLE |
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| Year : 2020 | Volume
: 21
| Issue : 2 | Page : 85-91 |
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Practical tips on making regional anesthesia safer
Ashwani Gupta, Rohit Garkoti
Department of Anaesthesia, Queen Elizabeth Hospital, Gateshead NHS Foundation Trust, Gateshead, England
| Date of Submission | 01-Jul-2020 |
| Date of Decision | 03-Jul-2020 |
| Date of Acceptance | 03-Jul-2020 |
| Date of Web Publication | 19-Sep-2020 |
Correspondence Address:
Dr. Ashwani Gupta
Queen Elizabeth Hospital, Gateshead NHS Foundation Trust, Gateshead
England
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/TheIAForum.TheIAForum_97_20
There have been many advances in regional anesthesia to make it safer since its inception. The purpose of the review is to make the readers aware of the latest developments in the approach to patient safety and its application to regional anesthesia. We have emphasized particularly the importance of human factors in addition to the technical expertise. Besides the conventional topics of local anesthetic toxicity and nerve injuries, we have also touched on novel developments such as point-of-care ultrasound. Anesthetists should bear in mind that guidelines are designed to encourage safe and quality patient care, but they cannot guarantee a specific outcome. So where possible safety protocols like pre-procedure dedicated checklist, vigilance and enhancements in monitoring, early evaluation and intervention, engagement with simulation based team training, advancements in technology, learning from safety incidents and positive patient pathways should be used to re-enforce safety. Regional anesthesia-based nontechnical skills (cognitive, social, and personal resource skills that complement technical skills) contribute to safe and efficient task performance and are also important in improving patient experience. The most practical safety approach is multidisciplinary, which keeps clinical judgment and patient-centric decision-making at its core. A literature search was done using the library search engine called discovery, which accesses Ovid, open access, evidence-based medicine, and nursing databases. Individual complications were also searched, and appropriate secondary citations were used accordingly.
Keywords: Human factors, local anesthetic toxicity, nerve injury, patient safety, simulation, stop before you block, ultrasound
How to cite this article:
Gupta A, Garkoti R. Practical tips on making regional anesthesia safer. Indian Anaesth Forum 2020;21:85-91 |
| Introduction | |  |
Regional anesthesia has evolved to its current form since its origin in 1884 when Carl Koller presented his findings on the use of local anesthesia for an ophthalmic procedure and published his work.[1] Increased availability and usage of portable ultrasound is one of the most important developments in the recent past which has enabled performance of high-quality nerve blocks and improvement of their safety profile. A safe conduct of RA would involve a thorough preassessment including appropriate investigations followed by a preanesthetic checklist, good anatomical knowledge, patient selection, technical/nontechnical skills, and awareness of human factors.
A literature search was done using the library search engine called discovery which accesses Ovid, open access, evidence-based medicine, and nursing databases. Filters were used to limit the search to peer-reviewed articles in English language within the past 20 years. Due to the open nature of the article, individual complications were also searched and appropriate secondary citations were used accordingly.
| Patient Safety | | |
Patient safety is about maximizing the things that go right and minimizing the things that go wrong for people experiencing health care and is integral to the definition of quality in health care.[2]
Patient safety is a dynamic concept and has neither a single objective measure nor a defined end point. The gold standard for safety will continue to be refined by new research and innovations as it responds to patient needs and system priorities.
In recent times, our concept of safety management has evolved from Safety-I to Safety-II.[3] A Safety-I approach presumes that things go wrong because of identifiable failures or malfunctions of specific embedded components: technology, procedures, the human workers, and the organization. The accident investigation in Safety-I is reactive and is entirely focused on identifying adverse incidents and errors and implementing adaptations to avoid their recurrence.[4] Safety-I view does not stop to consider why human performance practically always goes right and views it as a liability or hazard due to its variability.
Safety-II relates to the system's ability to succeed under varying conditions. Safety management here is proactive and moves from ensuring that “as few things as possible go wrong” to ensuring that “as many things as possible go right.”[3] A Safety-II approach sees variation of human performance as a resource necessary for system flexibility and resilience. It also assumes that this variation provides the adaptations that are needed for effectively responding to different conditions; hence is the reason why things go right. The accident investigation in Safety-II focuses on understanding of how things usually go right, challenges to human performance variability, and maintenance of the adaptive capacity to respond to unpredictable surprises.
| Local Anesthetic Toxicity | | |
Inadvertent intravascular injection is probably the most feared complication when we are injecting high concentration of local anesthetic. Injecting small aliquots at a time with frequent aspiration can minimize the risks. There is evidence that ultrasound has reduced the volumes injected which have resulted in reduced incidence of local anesthetic toxicity (LAST).[5] However, using ultrasound per se does not make regional anesthesia safer; a robust training program which relies on effective feedback and competency-based assessment is the key for the high-quality blocks.[6] Availability of intralipid and knowledge of its usage has certainly mitigated the risks of cardiac toxicity following accidental intravascular injection.[7] To minimize the risk of inadvertent intravascular injection, all the local anesthetic injections are required to be injected through nonluer lock needles in the UK which includes both peripheral and central neuraxial blocks.[8]
Like any other rare life-threatening complication, simulation is the key to provide experience in the management. All rooms where regional anesthesia is administered should have a copy of the guideline for the management of LAST with the availability of intralipid.
| Neurological Injury | | |
Nerve injury after an operation could be due to surgical or anesthetic causes. These could include direct trauma, ischemic insult due to positioning, tourniquet, plaster cast, and worsening of preexisting neurological deficit. The anesthetic causes could include direct needle trauma, inflammatory changes, toxicity of local anesthetic, particularly if injected intrafascicularly, and localized or diffused ischemia due to disruption of the vasa nervorum which maintains 50% of blood circulation to the nerves.[9] The incidence of new prolonged neurological deficit is 1 in 1000, of which 15% could be attributed to regional anesthesia which equates to 0.2 in 1000 or 1 in 5000.[10]
Certain medical conditions have an adverse impact on the microvasculature of the peripheral nerves which predispose these patients to a higher risk of nerve injury. Particularly vulnerable patients are with covert and overt preexisting neurological deficits. These could include patients with diabetes mellitus, peripheral vascular disease, and neuropathies due to various reasons. The presence of higher ratio of neural to connective tissue fibers makes the proximal nerve blocks more prone to insults compared to distal blocks. A typical example would include brachial plexus block performed at the interscalene level is more vulnerable to injury compared to axillary level.
Current ultrasound machines do not have the resolution to clearly differentiate between the neural and connective tissues. There is some evidence that opening injection pressure of more than 15 psi could indicate a very close needle nerve contact.[11] The use of short-beveled block needles is safer as less likely to cause traumatic nerve damage.[12] A muscle contraction at 0.2 mA at 0.1 ms pulse duration seems to reliably confirm intraneural placement of the needle.[13]
There is no clear evidence that the use of either nerve stimulator, ultrasound, or pressure monitor on their own could reduce the incidence of nerve injury. Due to the varied reasons and a relatively small incidence of nerve injury, it would probably never be possible to have a Level 1 or 2 evidence for the same. However, it is reasonable to use a combination of these to minimize the risks which is also supported by the expert panel of American Society of Regional Anaesthesia (ASRA).[14]
| Monitoring | | |
Any regional anesthetic procedure should only take place with monitoring as per the established standards including pulse oximeter, electrocardiograph (ECG), and noninvasive blood pressure (NIBP) monitoring with availability of resuscitation equipment. This should also include capnography if deep sedation is used for a procedure under nerve block.[15] The patient should be monitored up to 45 min after the conduct of a nerve block. This would help to recognize the toxic effects of systemically absorbed local anesthetic and a prompt response to hypoxemia if prior opioids were administered for analgesia.[16],[17]
| Anticoagulation Regional Anesthesia in Patient Receiving Antithrombotic or Thrombolytic Therapy | | |
The introduction of newer antithrombotic drugs increased understanding of venous thromboembolism and changing guidelines from various societies – sometimes conflicting has made regional anesthesia-related risks of patient harm a very relevant issue, where there is a need for constant vigilance along with awareness of local and national guidance. This is further complicated by the fact that very surgical specialties have their own guidance with regard to patient's risks of hemorrhage, which may not further align with hematology concerns.[18]
This creates a very challenging situation for the anesthetist, who should bear in mind that while these guidelines are designed to encourage safe and quality patient care, they cannot guarantee a specific outcome. The best way forward is a multidisciplinary approach, which keeps clinical judgment and patient-centric decision-making at its core.
Besides the dreaded spinal hematoma, recent guidelines have addressed the risk of significant bleeding in patients undergoing plexus and peripheral neural blockade. A full review of the latest guidance is beyond the scope of this article. Overall, there are suggestions that the risk of clinically significant bleeding in a spinal hematoma varies with age, associated abnormalities of the spinal cord or vertebral column, the presence of an underlying coagulopathy, difficulty during needle placement, and an indwelling neuraxial catheter during sustained anticoagulation perhaps in an additive versus synergistic multifactorial manner.
The risk–benefit of using regional anesthetic techniques is further convoluted by the use of newer anticoagulation drugs, variations in drug metabolism due to altered kidney function, differences in patient population, and synergistic effects of drugs including herbal medications.
Thus, an understanding of the complexity of this issue is essential to patient management. This, along with safety protocols that have preprocedure dedicated checklist, vigilance in monitoring for early evaluation of neurological dysfunction along with prompt radiological imaging and intervention will improve patient safety.
| Peripheral Nerve Catheters | | |
Siting of the peripheral nerve catheters (PNCs) is technically more demanding compared to single-shot blocks. However, the safety profile of PNCs is not dissimilar to single-shot nerve blocks. As mentioned earlier, full aseptic precautions should be taken to minimize the risk of infection. The increasing usage of ultrasound has increased the success rate of PNC.[19] Accidental falling out of the catheter could be minimized by tunneling and securing the catheter which would also mitigate the risk of infection.[20] Care has to be taken that the doses of local anesthetic administered do not exceed the maximum recommended doses[21] [Table 1].
To avoid an inadvertent injection, it is advised that the PNC is clearly marked with a bold label. It is paramount that members of the staff responsible for the care of these patients should be aware of potential complications including LAST and their management. A separate document for recording observations and troubleshooting should be available. Prescription of regular simple painkillers including paracetamol with nonsteroidal anti-inflammatory drug and a strong opioid for breakthrough pain helps to achieve the maximum benefit of the PNC as part of the multimodal analgesia.
| Asleep Versus Awake Blocks | | |
Central neuraxial anesthesia and interscalene should not be performed in patients who are under general anesthesia or heavy sedation due to high risk of injury to the spinal cord resulting from their inability to report the warning signs of paresthesia and/or pain on injection of local anesthetic.[22] Other peripheral nerve blocks in adults should preferably be avoided under general anesthesia or heavy sedation but could be considered where the risk of inadvertent injury to vital structures is higher due to noncooperation.[14]
Obviously, in pediatric patients, blocks are performed under general anesthesia where risks of injury due to noncooperation are much higher than the benefits which have to be weighed accordingly. The standard of safety is acceptable, however, caution has to be exercised as serious complications are still possible.[23]
| Aseptic Precautions | | |
Fortunately, the incidence of infectious complications following regional anesthesia is low. The national audit of complication of central neuraxial blocks over a year in the UK showed the incidence of epidural abscess of 15 in 707,425 or approximately 1 in 47,000 (2.1 in 100,000, 95% confidence interval, 1.2–3.5). The great majority of these were associated with epidural catheters who had underlying risk factors including leaving the catheters for more than 48 h.[24]
There was been no reported case of infection after 7576 ultrasound-guided single-shot blocks performed over 10 years in a single center.[25] Similarly, Auroy et al. did not report any infection in 43946 single-shot blocks.[26]
Aseptic recommendations for central neuraxial block[27] including epidural would involve handwashing, skin preparation with appropriate solution (alcohol-based 0.5% chlorhexidine gluconate solution are better than iodine based[28]), large drape, sterile gloves with surgical gown, cap, and face mask. Chlorhexidine solution on the skin needs to be dry before commencing the procedure to minimize contamination with CSF. Caution has to be exercised while application to avoid any direct contact of the chlorhexidine solution with the equipment including needle and/or catheter. A similar standard would apply for PNC insertion as well.
Aseptic recommendations for a single-shot nerve block would include handwashing, skin preparation with alcohol-based 0.5% chlorhexidine gluconate, sterile gloves with the use of sterile probe cover for the ultrasound probe, and sterile ultrasound gel.[29] A sterile drape could be considered. The ultrasound probe should be cleaned with appropriate disinfectant after every use. The local anesthetic solutions used for epidural and PNC should be prepared in a sterile environment preferably in pharmacy.
| Human Factors and Regional Anesthesia Nontechnical Skills | | |
Patient safety in health care is a global challenge that requires knowledge and skills in multiple areas, including human factors, which is an established scientific discipline used in many other safety-critical and high-reliability industries. Human factor approaches underpin current patient safety and quality improvement science, offering an integrated, evidenced, and coherent approach to patient safety, quality improvement, and clinical excellence.[30]
Human factor research examines the environmental, organizational, and job factors of humans interacting with systems, as well as the physiological and psychological characteristics which influence behavior at work, including understanding human error in patient safety, design of usable and safe medical devices and health IT, and importance of nontechnical skills[31] (the cognitive, social, and personal resource skills that complement technical skills and contribute to safe and efficient task performance).
Beyond knowledge and technical fluency, regional anesthesia-based nontechnical skills are very important for better patient experience and improved safety, including noncognitive skills such as handling of the patient (communicating, anticipating, and minimizing discomfort) and recognizing the limits of safe practice (deciding when to stop trying to siting a block).
| Wrong-Side Blocks | | |
Inadvertent wrong-sided peripheral nerve blocks are uncommon (with a reported incidence of up to 7.5 per 10000 procedures[32]) but can have serious consequences including complications from the unnecessary block (from nerve injury, LAST), delayed treatment/hospital discharge (from reduced mobility or dexterity) and may lead the team to continue to wrong-site surgery.[33]
There are various human factors which could lead to the incidents of wrong-side blocks, now classed in the UK as a “Never Event” within the wrong-site surgery category. A STOP moment, “Stop Before You Block” (SBYB), before the block is performed as a standard practice to reduce the incidence of wrong-sided blocks. SBYB is a UK national safety requirement that provides a strong, systemic barrier against wrong-site blocks with the following recommendations.[34]
- WHO checklist “Sign in” is performed as usual to confirm patient identity and consent form with operation and site of surgery
- Particular vigilance should be taken where:
- There is a delay between the “Sign in” and the performance of the nerve block
- After turning the patient, when the block site will have “moved” relative to the anesthetist
- If there are obvious distractions in the anesthetic room (such as excess personnel or interruptions since “Sign in”)
- Lower-limb nerve blocks are performed (as the surgical site arrow may not be immediately visible)
- Personnel who do not do regular regional anesthesia lists.
- ”STOP” moment occurs immediately before needle insertion in the nerve block process, and the correct site is confirmed again. In the UK, this is a two-person process involving the anesthetic assistant and the anesthetist.
Further suggestions[35] to reduce wrong-site blocks include awake patient, avoiding multiple blocks and changes to patient position, consistent approach to training, supervision, and reducing variability of practicing SBYB.
| Informed Consent | | |
Informed consent is a cornerstone of medical practice, and the need for consent before treatment is firmly embedded in modern health care. There is a wide variation in individual practice concerning the documentation of risks, benefits, and alternatives to regional anesthesia. Although there is guidance on the key principles of consent for regional anesthesia, there is no agreed national standard to guide the specific consent process for neuraxial blocks.[36] It is essential for anesthetists to document clearly both a patient's agreement to the intervention and the discussions that led up to that agreement, including the patient's questions and the responses given. This can be done on a standard consent form, on the anesthetic record, or separately in the patient's notes.[37]
| Compartment Syndrome | | |
Regional anesthesia is often implicated in compartment syndrome. However, there are numerous case reports which have suggested that patients have had compartment syndromes irrespective of the mode of analgesia. Regional anesthesia does not consistently mask the ischemic pain. Myelinated A (d) and unmyelinated C fibers carry the nociception in response to inflammatory and hormonal markers produced as a result of injury. In ischemic pain, tissue acidosis due to increasing hydrogen ions stimulates the nociceptors. The pain mediated through hydrogen ion is not completely blocked by low concentration of local anesthetic infusion through nerve catheter.[38]
The key to prevent compartment syndrome is close monitoring of analgesic use and trends of pain irrespective of the mode of analgesia in high-risk patients.[39]
| Point-of-Care Ultrasound | | |
Increased availability of portable ultrasound has added point-of-care ultrasound to the repertoire of anesthetists globally. The sensitivity of the lung ultrasound to detect pneumothorax is better than chest X-ray and similar to computerized tomography scan.[40] The quick and accurate confirmation of pneumothorax at the point of care with some training can only make regional anesthesia safer, particularly when performing blocks near the pleura including supraclavicular, paravertebral, and serratus plane to name a few.
| Intravenous Lignocaine | | |
There has been increasing use of intravenous (IV) lidocaine for acute perioperative pain. There is evidence that this is particularly helpful in colorectal surgery.[41] Caution should be exercised in sick patients, particularly with poor renal and liver function. IV lignocaine should only be administered by experienced anesthetists under close monitoring. Particular care has taken when co-administered with other local anesthetics in the form of blocks or infiltration with robust locally agreed guidelines of a safe duration between the two.
| Covid-19 and Regional Anesthesia | | |
The main advantage of regional anesthesia is reduction in the generation of aerosols by avoiding airway manipulation during intubation and extubation. However, the risk of infection through droplets and fomites is not reduced; hence, appropriate personal protective equipment (PPE) is recommended.
While performing nerve blocks near the head and neck, there is some evidence that enhanced PPE (respirator) is recommended.
Due to increased risk of thrombocytopenia, a whole blood count for platelet count is recommended before central neuraxial blockade.[42]
| Conclusion | | |
As the technology of the ultrasound is getting better and novel blocks are being described, a robust competency - based training will ensure continuing technical expertise.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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