Provocative Challenge Testing And Subsequent Successful Epidural Analgesia In A Morbidly Obese Patient With Known Local Anaesthetic Hypersensitivity
S Bandyopadhyay, R Wankhede, S Sengupta, A Rudra
anesthetics, complications: allergy, local: lidocaine
S Bandyopadhyay, R Wankhede, S Sengupta, A Rudra. Provocative Challenge Testing And Subsequent Successful Epidural Analgesia In A Morbidly Obese Patient With Known Local Anaesthetic Hypersensitivity. The Internet Journal of Anesthesiology. 2006 Volume 12 Number 2.
A 54 year old morbidly obese patient with suspected allergy to Lidocaine was posted for abdominal hysterectomy. She was additionally hypothyroid and had a grossly deranged PFT. A low thoracic epidural procedure with Bupivacaine infusion for intra and post-operative pain relief was planned. Provocative challenge with incremental doses of Bupivacaine were used for skin testing which yielded negative results. We went with the epidural technique and subsequently small epidural doses of the local anaesthetic were consistent with our skin test findings. Adequate analgesia was obtained using incremental dosing. Finally at the end of the procedure, we could actually extubate the patient on table. The post operative period was uneventful.
Adverse reactions to local anesthetics are rare (1) and are usually because of the paraben or sulfite preservatives in them. Allergy to local anesthetics has for a long time been considered a pseudo-allergic or anaphylactoid reaction (2). We present a case with known hypersensitivity to local anaesthetics who underwent provocative challenge testing with preservative free (PF) Lignocaine as well as Bupivacaine before a successful epidural analgesia ensued.
A 54 year old morbidly obese (MO) (body weight-110kgs, height-155cm, BMI-45.8), hypertensive, diabetic, hypothyroid and asthmatic patient was admitted to our hospital with acute onset breathlessness. On initial examination she was conscious, oriented but was very much distressed and orthopneic. She was hemodynamically stable . Chest auscultation revealed decreased breath sounds with varying degrees of bronchospasm and few crepitations in bilateral lung fields.
She was admitted in the ITU and initial treatment was started with nebulised Salbutamol and antibiotics.
the next one month she had recurrent episodes of respiratory distress which was consistent with acute LRTI complicating her primary respiratory condition ( COPD ). Judicious use of antibiotics and adequate respiratory care helped her condition to stabilize gradually over one month.
During the course of her hospital stay she was diagnosed with long term perimenopausal dysfunctional uterine bleeding, refractory to conservative therapy, and a plan for total abdominal hysterectomy with bilateral salpingo-oophorectomy was made.
Our patient had a convincing history of local anaesthetic hypersensitivity. So we decided to test it with PF Lignocaine as well as Bupivacaine. We continued the procedure with Bupivacaine since it has longer duration of action. The safety and utility of provocative challenge testing has been well established (3,4,5). We followed the methodology of Chandler et al.(6).
General anesthesia in MO patients generates much more atelectasis than in nonobese patients(7). Epidural analgesia (EDA) should be considered in obese patients undergoing midline laparotomy to improve postoperative spirometry(8). A large reduction of FVC occurs after lower abdominal surgery than after non-abdominal surgery on the first day after operation (9). The decrease in lung volume is thought to be related to pain and abdominal muscle spasm. Postoperative respiratory function is significantly more impaired in obese patients. As our patient was at high risk for postoperative pulmonary dysfunction owing to multiple factors, ensuring adequate pain relief was crucial. Our decision to carry on with provocative skin testing and subsequent epidural Bupivacacine turned out to be fruitful as the patient had a safe and uneventful recovery.
In the end, we conclude that true allergy to local anaesthetics is rare. In such cases where adequate pain relief using local anaesthetics is thought to improve patient outcome, a prior history of suspected allergy to local anaesthetics should not deter the anaesthesiologist from a provocative challenge test which in most cases have proven to be negative (10).