Delayed Respiratory Arrest in a Patient Following Interscalene Block: A Case Report with an Overview of Complications Associated with Interscalene Approach to Brachial Plexus BlockCorrespondence Address :
Dr. Aditya Nath Shukla. Lecturer in Anaesthesiology, Advanced Medical and Dental Institute, Universiti Sains Malaysia, No. 29, Lorong Bertam Indah 4/9, !3200, Kepala Batas, Penang, Malaysia. Tel.: +604-5752006; fax: +605751990; e-mail: email@example.com
Interscalene approach to the brachial plexus is the most proximal approach to brachial plexus and is utilised commonly for procedures performed on or near the shoulder joint and arm (1). This method of regional anaesthesia saves the patients from pain, nausea and vomiting, which are associated with general anaesthesia.
Although interscalene approach to brachial plexus block is quite safe, a wide variety of complications have been reported with it.
We report a case where a 56-year-old lady with flail chest and shoulder injury was undergoing a surgical toilet and debridement, with application of external fixator on left humerus upper shaft involving left shoulder joint, under interscalene block. The patient landed in cardiorespiratory arrest about half an hour in the procedure and nearly 50 minutes after the block was administered.
A 56-year-old female, 156 cm tall, weighing 56 kg, with ASA (American Society of Anesthesiologists) status III, was admitted to the hospital after having met with a road traffic accident.
The patient was a known case of chronic obstructive airway disease (COAD), had a chest injury with fracture of ribs 4â€“8 on left side, leading to a flail segment on left side, and compound Fracture left upper 1/3 humerus extending to involve the left shoulder joint. The patient was examined, investigated and excluded for any pneumothorax. Chest X-Ray had signs of COAD and fracture 4â€“8 ribs left side, and was otherwise unremarkable. The patient had a breath holding time of ~20 seconds. No other systemic abnormality was documented on history and examination and investigations otherwise were in the normal limit.
In view of the respiratory status and chest injury to patient it was decided to perform the surgery under interscalene approach to brachial plexus block.
Before starting with the procedure, patient was examined by a thoracic surgeon who advised strapping of the flail segment during the perioperative period. Accordingly, flail segment was strapped before taking up the patient.
The patient was placed supine with neck turned to other side. Block was performed using a 21 G, 25 mm needle. The needle was introduced on the left side in the interscalene grove, at the level of cricoid cartilage. After eliciting paraesthesia and negative aspiration, block was induced with 20 ml of 2% lignocaine with 1:200,000 epinephrine and 20 ml of 0.5% of bupivacaine, with negative aspiration performed initially and at every 10 ml in between. Pain experienced by patient gradually abolished. Adequacy of sensory effect was tested by pinprick after 20 minutes and was found to be adequate.
Patient was provided oxygen by nasal cannouae at 3 lpm and injection midazolam 2 mg iv.
At this point, the surgical team was allowed to proceed with the procedure. After about 20 minutes in the procedure, it was noticed that the patientâ€™s voice had diminished in intensity and over the next 10 minutes the patient gradually landed in aphonia. Respiration and other vital parameters were normal till this time. About 5 minutes later, the patient suddenly landed in apnoea and her heart rate started decreasing and she became unconscious. The patient was given injection atropine 0.6 mg iv and intubated immediately, and positive pressure ventilation was instituted. Patientâ€™s heart rate rose and settled in the normal range for the remainder of the procedure. The patient was ventilated with 100% oxygen initially for 20 minutes and then with O2:N2O in a 1:1 ratio. Her vitals signs remained stable otherwise throughout the rest of surgery; no further arrhythmia was documented. Additional midazolam 2 mg iv was provided with intubation. Patientâ€™s spontaneous respiratory efforts resurfaced over next 30 minutes and from then onwards patientâ€™s respiration was assisted. In the next 30 minutes, the patient had sufficient respiratory efforts to maintain the ventilation and was left on spontaneous ventilation on Ayerâ€™s T Piece with O2 at 4 lpm. By the time the surgical procedure was finished, the patient was awake and fully following verbal commands and was extubated.
Detailed examination of the patient in postoperative, and a day later, failed to reveal any persistent neurological deficit. The patient was discharged after 7 days.
Shoulder procedures are associated with severe pain. Interscalene brachial plexus block is an effective and reliable method of providing anaesthesia, with the persistent effect providing for some postoperative pain relief. Further, the technique is free from other side effects associated with general anaesthesia and also provides for good operating conditions with reduced blood loss, excellent muscle relaxation, reduced cost of treatment, etc. The performance of interscalene block with a standard technique and drug application is associated with a high success rate and with very few long-term complications.
The major acute complications/side effects associated with interscalene block are respiratory depression (due to associated ipsilateral phrenic block), intravascular injection that may lead to seizures and cardiac arrest, pneumothorax, epidural and spinal anaesthesia, Hornerâ€™s syndrome (ipsilateral cervical sympathetic block), and hoarseness and dysphagia (ipsilateral recurrent laryngeal nerve block) (2).
The case we described was of a young elderly lady with coexistent COAD and a flail segment; the patient required an urgent surgical intervention, as she had a compound fracture with intra-articular extension. Because of the respiratory status and coexistent flail segment in the patient, we wished to avoid general anaesthesia in her. Only interscalene approach to brachial plexus was suitable for her, as the surgery involved working on and in close proximity with the shoulder joint.
The performance of block was easy, as described by Winnieâ€™s technique. The sensory block was well established in the expected time. The surgery progressed well in the initial stage without any problem. However, about 40 minutes later, the problem started progressing to the extent where respiratory assistance was required. Subsequently, after another 30 minutes, spontaneous respiratory efforts were evident again and sufficient strength was restored over the next 30 minutes. Subsequently, the patient had complete recovery without any residual deficit.
The course of events in this case suggests delayed migration of local anaesthetic agent in the central neural space. However, whether the extension was into the extradural or subarachnoid space could not be commented on with certainty.
The central migration of the local anaesthetic agents in interscalene block is a known entity, and, though infrequently seen, cases have been documented in this regard. However, it usually occurs much earlier than in the case discussed. Also in the literature available, no case reported had coexistent acute chest injury. Further, the temporary strapping performed beforehand did provide the cover during assisted respiration.
Central neuraxial anaesthesia has been reported as the complication of interscalene block despite locating the brachial plexus easily with paraesthesia. This has usually been characterised by the fall of blood pressure and heart rate, extension of sensory and motor block outside the dermatomes expected for interscalene block, with or without involvement of the phrenic nerves. The patient may or may not retain the consciousness. The complication can present after interscalene block at varied time intervals, immediately following block to those delayed by up to 1 hour.
The central migration of drug can be to the spinal, epidural or subdural space, and indeed it may be difficult to identify the exact cause for the complication. However, the subdural spread can be suspected if the spread of block outside the brachial plexus is much patchy in distribution and is associated with minimal sympathetic block, and the interval between the initial block and onset of symptoms is too long (3). Spinal and epidural spreads are associated with relatively denser block with more profound sympathetic block. The motor component of the block is more in case of spinal spread.
This central neuraxial b
We all are aware that no procedure is absolutely safe and adequate for all patients, and interscalene approach to brachial plexus block is no exception from this rule. However, if following precautions are observed while performing interscalene block, then the complications associated with it can be minimised.
1. Always perform the block on an awake patient or patient under very light sedation
2. Any increase in pain, especially severe pain, should warn the anaesthetist of an intraneural injection and the adjustment in needle position should be made accordingly.
3. Avoid performing the block in an uncomfortable non-cooperative patient. General anaesthesia can be the alternative anaesthetic technique in these patients and then other approaches for postoperative analgesia can be adopted.
4. Always use a short bevelled needle ~25â€“35 mm in size, as most of the complications associated with block are encountered when one probes deeper for locating the brachial plexus.
5. Needle should be entered in the interscalene groove with a posteroinferior direction.
6. As interscalene block is a superficial block, inability to localise brachial plexus at 1â€“1.5 should prompt one that the needle may be in wrong plane and one should withdraw and re-enter rather than going more deep.
7. Each patient before undergoing interscalene block must be evaluated for the status of contralateral phrenic and recurrent laryngeal nerve function and if suspected should have a proper ENT examination.
8. Successful initiation of block and surgery does not guarantee outcome, as late complications can occur and constant vigilance and management of respiratory and circulatory system are mandatory.
9. There should be greater education and training for the nerve blocks to the trainee anaesthetist so that persons experienced in its performance are doing it, because complications are less in informed and experienced hands.
10. The greater use of ultrasonographic guidance may further increase the safety of procedure.
11. The physician should ensure that the patient does not move unexpectedly during the procedure and be prepared for it.
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