Plain ropivacaine dose linked to spinal hypotension after cesarean section

Plain ropivacaine dose linked to spinal hypotension after cesarean section | Image Credit: © natali_mis - © natali_mis - stock.adobe.com.

There is an association between spinal-induced hypotension and the plain ropivacaine dose among women receiving cesarean section, according to a recent study published in PeerJ.¹

Spinal anesthesia is commonly used during cesarean section, with data indicating ropivacaine as a well-tolerated anesthetic with low central nervous system toxicity. However, plain ropivacaine has been indicated as unpredictable compared to hyperbaric ropivacaine with glucose.

The risk of the patient being exposed to bacterial, particle, or other contaminations is increased by the introduction of additional medications administered into the spine. This indicates a need to optimize plain ropivacaine administration.

Hypotension is a common adverse outcome of spinal anesthesia.² However, there is little data about the impact of a plain ropivacaine dose on spinal hypotension incidence.¹

To evaluate the association between the plain ropivacaine dose and spinal hypotension incidence in patients undergoing cesarean sections, investigators conducted a single-center retrospective study. The Anesthesia Information Management System was assessed for data from January 2018 to December 2022.

Participants included women receiving single spinal anesthesia or combined spinal-epidural anesthesia (CSE) with 0.75% ropivacaine for cesarean delivery. Those with general anesthesia or epidural anesthesia administration during cesarean section were excluded from the analysis.

Patients received spinal anesthesia in the spinal position, with the intrathecal space found using a Quincke needle (22-gauge for spinal anesthesia; Zhejiang Fert Medical Equipment Co, Ltd, China). Following administration, patients were placed in the left lateral tilt position until posture requirements were made.

Relevant data included maternal age, hypertension disorder, maternal weight, gestational age, singleton or multiple pregnancies, single spinal anesthesia or CSE, anesthesia to incision time, anesthesia to delivery time, anesthesiologist seniority, anesthesia puncture site vasopressor use, and planned or emergency surgery.

The dose of plain ropivacaine administered was reported as the primary exposure of the analysis and the frequency of spinal hypotension as the primary outcome. Vasopressor use was also reported as a secondary outcome.

Categories for plain ropivacaine doses included Q1 at 15.75 mg or under, Q2 at 15.76 to 16.50 mg, Q3 at 16.51 to 17.25 mg, and Q4 at 17.26 mg or higher. Receiver operating characteristic (ROC) curves were used to evaluate the threshold ropivacaine dose.

There were 1219 women included in the final analysis, 72.3% of whom experienced hypotension. Metaraminol administration was reported in 51.2%, ephedrine in 12.8%, and both vasopressors in 4.6%. Of patients, 26/4% were in Q1, 34.5% Q2, 15.3% Q3, and 23.8% Q4.

A higher rate of spinal hypotension was reported in the Q4 cohort vs the other cohorts, at 85.4% and 68.1%, respectively. This indicated an adjusted odds ratio (OR) of 2.71. Based on the ROC curve of 0.5748, the model was able to differentiate between patients with and without hypotension.

Similar results were reported during the sensitivity analysis, with an OR of 2.64. Additionally, while the plain ropivacaine dose was not association with ephedrine use, an association was reported between the dose and metaraminol use.

These results indicated an association between the plain ropivacaine dose during cesarean delivery and spinal-induced hypotension incidence. Investigators noted that both dose groups had significant spinal hypotension incidence requiring titration vasopressor therapy.

References

1. Li M, Xie G, Chu L, Fang X. Association between plain ropivacaine dose and spinal hypotension for cesarean delivery: a retrospective study. PeerJ. 2024;12:e18398. doi:10.7717/peerj.18398
2. Campbell JP, Stocks GM. Management of hypotension with vasopressors at caesarean section under spinal anaesthesia – have we found the Holy Grail of obstetric anaesthesia? Anaesthesia. 2018;73(1):3-6. doi:10.1111/anae.14114