Local anaesthetic toxicity after bilateral thoracic paravertebral block in patients undergoing coronary artery bypass surgery.
We conducted a small pilot observational study of the effects of bilateral thoracic paravertebral block (BTPB) as an adjunct to perioperative analgesia in coronary artery bypass surgery patients. The initial ropivacaine dose prior to induction of general anaesthesia was 3 mg/kg, which was followed at the end of the surgery by infusion of ropivacaine 0.25% 0.1 ml/kg/hour on each side (e.g. total 35 mg/hour for a 70 kg person). The BTPB did not eliminate the need for supplemental opioids after CABG in the eight patients studied. Moreover, in spite of boluses that were within the manufacturer's recommendation for epidural and major nerve blocks, and an infusion rate that was only slightly higher than what appeared to be safe for epidural infusion, potentially toxic total plasma ropivacaine concentrations were common. We also could not exclude the possibility that the high ropivacaine concentrations were contributing to postoperative mental state changes in the postoperative period. Also, one patient developed local anaesthetic toxicity after the bilateral paravertebral dose. As a result, the study was terminated early after four days. The question of whether paravertebral block confers benefits in cardiac surgery remains unanswered. However, we believe that the bolus dosage and the injection rate we used for BTPB were both too high, and caution other clinicians against the use of these doses. Future studies on the use of BTPB in cardiac surgery patients should include reduced ropivacaine doses injected over longer periods.
Professor, Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR; currently Professor, Department of Anesthesiology and Perioperative Medicine, Queen's University, Kingston, Ontario, Canada.
A M-H
AM
Ho
Professor, Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
M K
MK
Karmakar
Consultant, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
S K
SK
Ng
Professor, Department of Surgery, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
S
S
Wan
Consultant, Department of Surgery, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
C S H
CS
Ng
Consultant, Department of Surgery, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
R H L
RH
Wong
Consultant, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
S K C
SK
Chan
Professor and Chair, Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
G M
GM
Joynt
D000368:Aged; D000577:Amides / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000009:adverse effects*; D001026:Coronary Artery Bypass; D006801:Humans; D008875:Middle Aged; D009407:Nerve Block / Q000009:adverse effects*; D000077212:Ropivacaine
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine
ischaemic heart disease, local anaesthetic toxicity, paravertebral block, regional anaesthesia, ropivacaine, troponin