Underused approach: subarachnoid block for a laparoscopic cholecystectomy? A case report and discussion of anaesthetic and surgical considerations

Abstract

We present a case of laparoscopic cholecystectomy with subarachnoid block (SAB) in an opioid-tolerant patient with chronic obstructive pulmonary disease (COPD). A 64-year-old woman presented to the emergency department with acute abdominal pain of biliary colic. Surgery was delayed in favour of conservative management given that she was considered high risk for general anaesthesia. Due to refractory pain, she successfully proceeded to have laparoscopic cholecystectomy with SAB. This case is a timely reminder that SAB is feasible and safe in patients with severe COPD, with the added benefit of increased analgesic effects, fewer postoperative pulmonary complications and quick recovery time.

Case presentation

A 64-year-old woman presented to hospital with a 1-day history of acute right upper quadrant (RUQ) pain on the background of similar episodes in the preceding few months. The pain was spasmodic, radiated to the back, intermittent initially and became constant. She had three episodes of diarrhoea, but no associated nausea and vomiting (N&V) or rectal bleeding.

Medical history included known cholelithiasis and severe chronic obstructive pulmonary disease (COPD). She was on methadone maintenance therapy for previous intravenous drug use. Her recent surgical history comprised an open reduction internal fixation (ORIF) of neck of femur fracture under subarachnoid block (SAB), and ORIF of left wrist fracture under an interscalene block. She had no intervention under general anaesthesia (GA) in the past 5 years.

On examination, she was haemodynamically stable and afebrile. She had RUQ tenderness and Murphy’s sign was positive. Laboratory investigations were unremarkable. Abdominal ultrasound confirmed a single non-mobile gallbladder calculus with no evidence of acute cholecystitis or hepatobiliary obstruction.

Treatment

She was admitted under general surgery for management of biliary colic. Over the next few days, her RUQ pain remained uncontrolled despite increasing her opioid analgesia and daily involvement from the acute pain specialists. She developed opioid-induced N&V following usage of oral oxycodone 200 mg and subcutaneous fentanyl 375 μg over 24 hours while her methadone was maintained.

Laparoscopic cholecystectomy (LC) was deemed the best therapeutic option to manage the refractory pain. Respiratory physician consult confirmed that her COPD was already fully optimised with daily tiotropium/olodaterol and ciclesonide inhalers, therefore, there would be no benefit in postponing surgery to improve lung function. In collaboration with anaesthetists and considering the likelihood of adverse perioperative respiratory outcomes, SAB was chosen instead of GA for LC. The plan was well explained to the patient and she was aware of GA as a backup option and the necessity of postoperative ventilation.

A 3.5 mL dose of 0.5% heavy bupivacaine and 200 μg of intrathecal morphine were injected at L3/4 intervertebral level. Sedation was achieved via dexmedetomidine infusion with bolus 1 μg/kg and maintenance titrated between 0.2 μg/kg/hour and 0.5 μg/kg/hour, and intravenous midazolam 2 mg. This was later supplemented with propofol 1% infusion titrated to effect between 10 mL/hour and 40 mL/hour due to patient anxiety. There was an initial drop of heart rate from 100 beats/min to 65 beats/min with initiation of SAB which improved with atropine 600 μg and remained stable thereafter. Oxygenation was maintained at 4 L/min via nasal specs initially, then increased to 6 L/min via Hudson mask. Oxygen saturation from pulse oximetry was stable throughout the procedure between 92% and 98%.

A standard umbilical port was inserted and capnoperitoneum was established under close observation. The insufflation rate was deliberately kept under 5 L/min to allow for slow and controlled distension of the abdominal wall. Low-pressure capnoperitoneum was maintained between 5 mm Hg and 7 mm Hg for the entire procedure. A laparoscopic dissection of adhesions of greater omentum to the gallbladder, followed by a standard LC was performed. The operation time was about 45 min. The surgical procedure was at no stage impaired by the low-pressure capnoperitoneum or SAB.

Outcome and follow-up

There was close postoperative monitoring in view of intrathecal morphine and recovery was uneventful. Ketamine infusion was able to be discontinued the day after surgery. She required 30 mg of oral oxycodone in the first 24 hours postoperatively. She was discharged on the second postoperative day without oxycodone, and methadone dose was increased temporarily from 65 mg to 70 mg daily. Follow-up was with her primary care provider

Discussion

LC is the treatment of choice for symptomatic cholelithiasis. Capnoperitoneum causes physiological changes such as hypercarbia, hypoxaemia and shoulder pain from diaphragmatic irritation. It is usually perceived that LC necessitates GA for prevention of aspiration, adequate analgesia and control of ventilation and haemodynamics.¹

In recent years, there is a growing body of evidence including randomised controlled trials demonstrating that SAB in LC using low-pressure capnoperitoneum is a safe and feasible alternative to GA for otherwise healthy patients.^2–4 SAB is often used routinely in low/middle-income countries where the cost factor may limit availability of GA.⁵ Conversely, it appears to be an overlooked or underused approach in resource-rich first-world countries. In our high-risk patient, conservative management was trialled first in order to avoid the risks of GA. Regional anaesthesia (RA) as an option was not considered until a late stage where the patient’s uncontrolled pain and failed conservative management required definitive surgical intervention.

LC under SAB is still generally reserved for patients in whom GA is considered high risk, including patients with COPD. For this group of patients, there is an elevated risk associated with intubation and intermittent positive pressure ventilation of causing bronchospasm, hypoxaemia, barotrauma or difficult extubation and weaning from ventilation.⁶

In patients with COPD, there is a compounded risk of respiratory failure due to hypercarbia and reduced diaphragmatic excursion from capnoperitoneum. Mechanical ventilation in GA assists with carbon dioxide (CO₂)elimination, reducing the risk of hypercarbia and its complications including acidosis or arrhythmias.⁷ Despite the absence of mechanical ventilation where RA is used, studies have shown that severe asthma or COPD (American Society of Anesthesiologists grade III/IV) is not a contradiction to LC under RA.^{7 8} This is because hypercarbia can be reduced by using low-pressure capnoperitoneum of <10 mm Hg with slow CO₂ insufflation,⁹ and limiting the duration of insufflation when possible.¹ It is likely that with a lower intra-abdominal pressure, normal diaphragmatic excursion is maintained and the patient can adequately increase minute ventilation to compensate for hypercarbia. Furthermore, the risk of shoulder pain is also minimised.¹⁰

SAB was also chosen for its improved analgesia effect. A systematic review of healthy patients undergoing LC found that RA was associated with less intense postoperative pain, and thus less prevalent postoperative N&V compared with GA.¹¹ There is significantly less analgesia requirement in patients with COPD who had LC under SAB compared with GA.⁶ As a result, patients with SAB had a lower rate of respiratory complications compared with GA patients (0% vs 13.3%, p=0.112).⁶

Surprisingly, despite reports on the safety and efficacy of SAB for LC, the technique has yet to gain widespread acceptance.^{3 12} Problems related to the technique of SAB include intraoperative hypotension requiring the use of ephedrine, and right shoulder pain due to diaphragmatic irritation from pneumoperitoneum requiring conversion to GA in a small proportion of patients.^{11 12}

In this case, a standard surgical approach to LC was used. The procedure was surgically slightly more challenging due to chronic cholecystitis with adhesions to the gallbladder requiring laparoscopic division. At no point was the safety of the procedure compromised by the low-pressure capnoperitoneum or the choice of anaesthesia. This view is supported by studies showing similar operative times between SAB and GA for LC.^{2 4} A caveat is that this approach needs good communication between the surgical and anaesthetics team while establishing the capnoperitoneum. Stretching of the abdominal wall and diaphragm can cause the patient significant discomfort and pain. A careful and slow instigation of capnoperitoneum using low flow and pressure settings on the insufflator mitigates this.

In summary, we present this case as a timely reminder for surgeons and anaesthetists to consider SAB for LC as safe and feasible alternative to GA as it is well documented and used routinely in certain regions. Low-pressure capnoperitoneum of 5–7 mm Hg was used successfully without compromising a safe surgical approach, and respiratory function was stable perioperatively. The combination of dexmedetomidine, intrathecal morphine and SAB helped to minimise postoperative opioid requirement and enhanced recovery.

Patient’s perspective.

The hardest thing was waiting for 4 days with the severe pain before having the procedure. The doctors could not manage my pain due to my methadone tolerance. Due to complications with my breathing problems I knew it was not safe for me to have a general anaesthesia. It was nerve wracking as the procedure under spinal anaesthesia wasn’t commonly done in Australia, and I was worried whether I would feel any pain during the procedure under spinal anaesthesia. The doctors were very helpful. Before the procedure, they came and explained everything about what they would do and reassured me it would be alright. Once they put the epidural in my back, I did not feel any pain. I was sedated until they almost finished stitching up and did not have any pain in the recovery suite. My recovery was good, I had minimal pain for the first couple of days and recovered more quickly than expected. I was glad that it was over and that the pain I had before the procedure was gone. It was a good thing I had the procedure under spinal anaesthesia because now other people can have the same procedure without having to wait with the pain, as the doctors know that it works.

Learning points.

• In developed countries, laparoscopic cholecystectomy under subarachnoid block appears to be a forgotten or overlooked approach. It is well documented and a safe alternative to general anaesthesia and is used routinely in certain regions.

• Laparoscopic cholecystectomy under subarachnoid block may be a viable option for patients with severe chronic obstructive pulmonary disease (COPD) as it reduces the risk of extubation, respiratory depression and postoperative mechanical ventilation.

• Subarachnoid block in patients with COPD, when low-pressure and low-flow capnoperitoneum is used, are able to compensate for hypercarbia and have stable perioperative respiratory function. Low-pressure capnoperitoneum at 5–7 mm Hg also prevents excessive abdominal wall stretching and reduces patient discomfort.

• Subarachnoid block has the additional benefit of superior analgesia effect, reducing postoperative opioid requirement which can cause respiratory depression in patients with COPD. This also enhances post-operative recovery.

Ethics statements

Patient consent for publication

Obtained.