Page 124 - BSAVA Guide to Pain Management in Small Animal Practice

p e

VetBooks.ir

Thoracic pain

Ana Marques

Thoracotomy is associated with severe acute bolus. In humans, opioids can cause central
postoperative pain. It can adversely a ect respiratory depression and contribute to
coughing and deep breathing, resulting in postoperative hypoventilation. In animals, these
respiratory complications such as hypoxia, side e ects are rarely observed at clinical
atelectasis, chest infection, and respiratory doses; however, monitoring is advisable.
failure that may delay recovery or, if severe, be Intravenous constant rate infusions CRI can
life-threatening (Kavanagh et al., 1994; Pavlidou minimi e dose dependent adverse e ects by
et al., 9 . avoiding peaks in serum concentrations.
Acute pain control is important to prevent Changes in dosage are also easily
splinting and stretching of the surgical incisions accomplished and have a predictable onset
as a result of breathing, and to help provide when infusion pumps are used.
e ective pre emptive analgesia. Pain is relayed The use of regional analgesia can minimize
via the intercostal and phrenic nerves and leads the pain associated with rib spreading, which is
to an in ammatory cascade, which decreases considered one of the most important factors
the pain threshold and sensiti es the a ected involved in post-thoracotomy pain (Fibla et al.,
peripheral nerves. Continued stimulation can 9 . It has the potential advantage of
result in central sensitization and higher providing analgesia without central respiratory
incidence of chronic pain (Sabanathan et al., depression or sedation, allowing improved
199 ; at et al., 1996 . ventilation and easier evaluation Pascoe and
A multitude of strategies for pain control and yson, 199 ; Con emius et al., 1994 . Local
the timing of analgesia administration have been anaesthetics, such as bupivacaine and lidocaine,
widely discussed. Experimental and clinical can be delivered in the form of intercostal nerve
studies have shown that neuronal a erent blocks, as a single injection across a range of
blockade applied before injury can reduce dermatomes or through placement of sterile
postoperative pain, providing a rationale for catheters (paravertebral catheter, thoracostomy
pre emptive analgesia oolf and Chong, 199 . drain and wound soaker catheter elms et al.,
pioids are commonly used as a rst line of 11; ranci et al., 1 ; ildgaard et al., 1 .
analgesia and delivered as an intravenous Thoracostomy drains allow delivery of local

BSAVA Guide to Pain Management in Small Animal Practice. Edited by Ian Self. ©BSAVA 2019 119

Ch07b Pain Management.indd 119 19/12/2018 10:40