The aim of this study was to examine the effect of keeping the patient in a sitting position
for 1 minute after spinal anaesthesia in elective caesarean operations, primarily on the
formation of hypotension and secondarily on nausea-vomiting, the need for ephedrine and the
block characteristics.
Hypotension
Clinical Trial – Influence of Injection Rate of Intrathecal Mixture of Local Anesthesia on Hypotension in Cesarean Section
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.
Clinical Trial – Hemodynamic Impact of Hyperbaric Versus Isobaric for Spinal Anesthesia During Cesarean Delivery
The purpose of this study is to compare the frequency of hypotension between hyperbaric
anesthetics and isobaric anesthetics during cesarean section and determine whether continuous
infusion of phenylephrine is effective in mothers who received hyperbaric anesthetics.
Clinical Trial – ET50 With Fentanyl for Post Caesarean Section Spinal Hypotension
Hypotension is extremely common after induction of spinal anesthesia for cesarean delivery.
Anesthetic blockade of the sympathetic outflow of the spinal cord causes vasodilation, and is
one cause of this hypotension. The higher the spread of the blockade will result in a higher
incidence of hypotension. Injected hyperbaric medication has about 15 minutes to spread
within the intrathecal space before it will be taken up by the nerve roots. The time that a
patient remains in one position after medication injection will affect the spread of the
resultant anesthetic block. A patient who is left sitting for a longer period of time after
injection of hyperbaric medication will have a lower level of block than someone who is
placed supine immediately. In this study, the investigators wish to use up down sequential
analysis to determine the time period a patient should remain seated after intrathecal
injection of hyperbaric bupivacaine and fentanyl that will result in a 50% rate of
hypotension.
Clinical Trial – ET 50 for Post Caesarean Section Spinal Hypotension
Hypotension is extremely common after induction of spinal anesthesia for cesarean delivery.
Anesthetic blockade of the sympathetic outflow of the spinal cord causes vasodilation, and is
one cause of this hypotension. The higher the spread of the blockade will result in a higher
incidence of hypotension. Injected hyperbaric medication has about 15 minutes to spread
within the intrathecal space before it will be taken up by the nerve roots. The time that a
patient remains in one position after medication injection will affect the spread of the
resultant anesthetic block. A patient who is left sitting for a longer period of time after
injection of hyperbaric medication will have a lower level of block than someone who is
placed supine immediately. In this study, the investigators wish to use up down sequential
analysis to determine the time period a patient should remain seated after intrathecal
injection of hyperbaric bupivacaine that will result in a 50% rate of hypotension.
Clinical Trial – Intravenous Ondansetron to Attenuate the Hypotensive, Bradycardic Response to Spinal Anesthesia in Healthy Parturients
The investigators hypothesize that given prophylactically, intravenous ondansetron will
attenuate the drop in blood pressure and heart rate frequently seen after spinal anesthesia.
Eighty-six American Society of Anesthesiologists (ASA) physical status I or II in
preoperative patient assessment, parturients age of 18 to 45 years scheduled to undergo
elective caesarean section will be enrolled.
Patients will be randomized to 2 groups: the ondansetron group, receiving 8 mg intravenous
ondansetron diluted in 10 mL of saline; or the placebo group, who were administered 10 mL of
saline given 5 minutes prior to performing the spinal anesthetic. Investigational Pharmacy
will randomize and dispense study drug.
Baseline measurements of vital signs will be taken. Otherwise standard management will then
be used:
– Patients must be NPO for 8 hours
– Pulse oximetry, EKG monitoring, noninvasive blood pressure at a minimum of every 3
minutes, more frequently if decided by the provider.
– Standard lumbar puncture in a sitting position the L3-L4 or L4-L5
– Whitacre pencil-point, 25 gauge
– Injectate: 2 mL of 0.75% hyperbaric bupivacaine, 100 mcg preservative free morphine, 20
mcg fentanyl
– Immediately after completing the subarachnoid injection, patients will be laid supine
with left lateral uterine displacement
The sensory level of anesthesia will be assessed in the standard fashion every five minutes
using ice. The motor component will tested using the Bromage scale for spinal anesthesia (0,
no paralysis; 1, inability to lift the thigh [only knee/feet]; 2, inability to flex the knee
[only feet]; 3, inability to move any joint in the legs).
Clinical Trial – A Study Comparing Two Spinal Techniques for for Cesarean Delivery Anesthesia
The purpose of this study is to compare single shot versus sequential bolus spinal technique
via a catheter in patients undergoing Cesarean Section. We aim to determine which technique
results in less blood pressure reduction and subsequent vasopressor use.
Other study endpoints include the incidence of maternal post dural puncture headaches and
nausea and vomiting. In addition blood and CSF will be collected to see if biochemical
mediators are related to wound hyperalgesia and healing.