Could Intrathecal Fentanyl Prevent Shoulder Tip Pain (STP) During and After Caesarean Section

The most common surgery performed on women around the world is caesarean section. The majority of caesarean sections these days are carried out under regional analgesia, though some need to be carried out under general anesthesia, particularly in emergency situations or when there is a contraindication to the use of regional anesthesia. Benefits of spinal anesthesia include an awake mother at birth, minimizing or avoiding the risk of general anesthesia (aspiration, difficulty intubation, etc.) and minimal side effects to the newborn.

Shoulder tip pain (STP) is a usual complication after laparoscopy with the incidence reported varying between35% to 80%. Recent studies suggest that this type of pain is also seen after cesarean section Shoulder pain is commonly observed, but is largely ignored complication of caesarean section, and little is understood or studied regarding intraoperative shoulder pain.

Shoulder pain can be more excruciating in some patients than the pain from the surgical incision. This pain may be associated with diaphragmatic irritation/injury from local acidosis, the irritating effects of carbon dioxide during pneumoperitoneum, or stretching forces on the diaphragm. ( Although carbon dioxide is not used in cesarean compared to laparoscopic surgeries, stretching forces on the diaphragm during cesarean can be one of the causes of shoulder pain in these patients.

It is believed that seepage of blood or amniotic fluid into the abdomen accumulation during cesarean section and subdiaphragmatic may be the cause of STP. Retained blood clots in patients undergoing CS can induce diaphragmatic discomfort and stimulate the phrenic nerve. Peritoneal cleaning and visceral manipulation also may play a part.

Fentanyl is a commonly used lipophilic opioid for spinal anesthesia with relatively approved intraoperative anti-nociceptors effect.

Inclusion criteria

• ASA physical status I-II,
• uncomplicated, singleton pregnancies of at least 36 weeks gestation.

Exclusion criteria

• Cardiac, liver or renal disease
• Allergy to amide local anesthetics
• History of epilepsy or any other neurological problem
• Any contraindication of regional anesthesia, or patient refusal
• Intrauterine growth restriction or fetal compromise