The Efficacy Of Nalbuphine Versus Fentanyl As Additives To Bupivacaine In Spinal Anaesthesia
For Internal FixationI Of Tibia
Hypotension is the most common complication of neuraxial anesthesia in obstetric patients and
its prevalence in cesarean section is about 50-90%. Maternal hypotension causes unpleasant
symptoms such as nausea, vomiting, loss of consciousness, respiratory depression, and cardiac
arrest. Hypotension may reduce placental perfusion and result in fetal acidosis and
neurological injury. Several techniques have been proposed to prevent hypotension.
The recommended spinal block height to ensure patient comfort for Cesarean delivery is T4-6.
Clinically, it is desirable that the spread of local anesthetic through the cerebrospinal
fluid (CSF) achieves a sensory level no higher than the T4 dermatome to avoid extensive
sympathetic block. It is also important that the spinal block level be no lower than T6 to
avoid patient discomfort during peritoneal manipulation and uterine exteriorization. The
effect of injection speed on spread of spinal anesthesia is controversial. Several studies
have demonstrated more extensive spread with faster injection while others report either
greater spread with slower injection, or no difference. Slow injection of hyperbaric
bupivacaine 10 mg over 60 and 120 sec has been shown to reduce the incidence and severity of
hypotension during Cesarean delivery under spinal anesthesia.
Morphine is usually used for pain relief after cesarean delivery. However, sometimes it is
not available, the patient might be allergic to morphine or intolerant to its side effects.
Hydromorphone, another drug from the same class, might be used alternatively, but we need to
prove that it is not inferior to morphine.
The incidence of chronic post-surgical pain (CPSP) after caesarean section (CS) is reported
to be as high as 18%, reflecting it to be a significant clinical problem. Studies related to
prevention of progression of acute post-CS pain to its chronicity are sparse. Current
guidelines on post-CS analgesia recommend the use of intrathecal (IT) opioids to spinal
anaesthesia for improved post-CS pain relief. Despite its frequent use, studies related to
the IT morphine use and its association with post-CS chronic pain are lacking.
A recent prospective observation study revealed a significant reduction in persistent pain
after CS when IT morphine was used as an adjuvant to spinal anaesthesia. However, there is no
any randomized controlled trial (RCT) that has explored this association to date. We
hypothesized that spinal morphine would reduce the incidence of persistent pain after CS.