Introduction
The
serratus anterior plane block (SAPB)
is a regional anesthesia method whereby local anesthetics (LAs) are
injected into the serratus anterior space to block the lateral cutaneous
branch of the intercostal nerve, long thoracic nerve, and dorsal
thoracic nerve[1]. It has been increasingly
acknowledged that SAPB can produce effective analgesia for the chest
wall because it fully covers surgical incisions impacted by
thoracoscopic surgery and the site of the chest tube, which are often
located in the anterolateral chest wall[2].
Continuous techniques are highly recommended for prolonged analgesia
duration [3, 4], and we and others have
successfully implemented continuous SAPB for multiple surgical
procedures [2, 4-7], including video-assisted
thoracoscopic surgery (VATS).
The efficiency of regional analgesia is importantly dependent on the
volume and concentration of the LA solution[8].
However, potentially toxic plasma concentrations of LAs have been
reported after administration of transversus abdominus plane (TAP) block[9, 10], especially in patients with hepatic or
renal insufficiency. It has been commonly seen that SAPB is performed
clinically using different concentrations of ropivacaine, ranging from a
minimum of 0.125% ropivacaine to a maximum of 0.75%
ropivacaine[11-13]. At present, the safety of
different concentrations of ropivacaine in SAPB has not been well
studied, especially under the condition of continuous administration of
LAs. The objective of this prospective randomized study was therefore to
compare the analgesic efficacy and pharmacokinetics of ultrasound-guided
continuous SAPB using 0.2% and 0.375% ropivacaine in patients
undergoing VATS.