The epidural "top-up" in combined spinal-epidural anesthesia: the effect of volume versus dose

Prophylactic infusion of norepinephrine does not affect the rostral spread of spinal anesthesia in pregnancy: a prospective, randomized, double-blinded study

Background: The infusion of phenylephrine to prevent spinal-induced hypotension (SIH) in cesarean delivery may decrease the rostral spread of a spinal local anesthetic. We hypothesized that infusion of norepinephrine may decrease the rostral spread of spinal anesthesia, similar to that caused by phenylephrine. The aim of this study was to compare the block height of spinal anesthesia in the presence or absence of norepinephrine infusion administered to prevent SIH during cesarean delivery. Methods: Eighty patients were enrolled and allocated into groups receiving a norepinephrine infusion (group N) or saline infusion (group C). After intrathecal injection of hyperbaric bupivacaine 10 mg, the block height for cold and pinprick sensation was checked 10 and 20 min after the injection. The demographic characteristics, spinal anesthesia, side effects, and neonatal outcomes were also recorded. Results: The block height for cold and pinprick sensation was similar between the two groups, although the incidence of hypotension was significantly lower (p < 0.00) in group N than in group C. Systolic blood pressure was also more stable in group N than in group C, with the incidence of interventions being significantly lower in group N. There was no significant difference in patient satisfaction between the two groups. Conclusion: Evidence from this study suggested that prophylactic norepinephrine infusion does not reduce the rostral spread of spinal anesthesia in pregnancy. We suggest that it is not necessary to increase the dose of an intrathecal local anesthetic for cesarean delivery when prophylactic norepinephrine is administered. Clinical Trial Registration: https://www.chictr.org.cn/bin/project/edit?pid=152899, identifier [ChiCTR2200057439].

Comparison of the Efficacy and Safety of Morphine and Fentanyl as Adjuvants to Bupivacaine in Providing Operative Anesthesia and Postoperative Analgesia in Subumblical Surgeries Using Combined Spinal Epidural Technique

Introduction:

The combined spinal epidural (CSE) technique involves intentional subarachnoid blockade and epidural catheter placement during the same procedure to combine their individual best features, to reduce the total drug dosage and avoid their respective disadvantages. The addition of opioids to local anesthetics (bupivacaine) for CSE anesthesia (CSEA) is increasingly common to enhance the block. Neuraxial fentanyl is more potent and has shorter duration of action than morphine which provides prolonged anesthesia and analgesia, however at the cost of increased incidence of adverse effects like delayed respiratory depression.

Aims and Objectives:

The aim is to compare the efficacy and safety of morphine and fentanyl as adjuvants to bupivacaine in subumblical surgeries using CSE technique. The characteristics of sensory and motor block, intergroup variations in pain, cardiorespiratory parameters, and adverse effects were compared between the two groups.

Materials and Methods:

A total of 60 patients belonging to physical status American Society of Anesthesiologists Classes I and II, aged 18–60 years were randomized into two groups: Group A (n = 30) received intrathecal 0.5% heavy bupivacaine 12.5 mg and morphine 2.85 μg/kg; Epidural Anesthetic bolus (when required/T11Regression) 8 ml 0.25% isobaric bupivacaine and 0.04 mg/kg morphine; Epidural Analgesic bolus (postoperative visual analog scale [VAS] score >30) 5 ml 0.125% isobaric bupivacaine and 0.04 mg/kg morphine and Group B (n = 30) received intrathecal 0.5% heavy bupivacaine 12.5 mg and fentanyl 0.35 μg/kg; Epidural Anesthetic bolus (when required/T11Regression) 8 ml 0.25% isobaric bupivacaine and 0.7 μg/kg fentanyl; Epidural Analgesic bolus (postoperative VAS score >30) 5 ml 0.125% isobaric bupivacaine and 0.7 μg/kg fentanyl.

Results and Conclusion:

Group A had significantly prolonged two segment regression time, T11 regression time, lower mean VAS score, prolonged effective analgesia, and required lesser number of epidural boluses in 24 h as compared to Group B (P < 0.001). There were no significant differences between the groups considering onset of sensory block, duration of motor block, median maximum sensory block level achieved after spinal component (T6), median highest sensory block level achieved after epidural anesthetic bolus (T7-4seg enhancement after regression to T11), cardiorespiratory parameters and adverse effects. None of the patients had respiratory depression nor was there any failure of spinal/epidural component of CSEA. Thus, addition of morphine to bupivacaine in CSEA produced prolonged effective anesthesia and postoperative analgesia compared to addition of fentanyl to bupivacaine without producing undue adverse effects.

Minimum effective volume of normal saline for epidural volume extension

BACKGROUND

Rescue strategies like changes in tilt of table are used to raise the level of an inadequate sensory block following intrathecal injection. Epidural volume extension (EVE) refers to an injection of normal saline through epidural catheter following an intrathecal block. It results in a rapid increase in the sensory level of subarachnoid block. Thus, it has been postulated that EVE may be used as a rescue strategy for an inadequate post-spinal sensory block. However, the minimum effective volume (MEV) of normal saline for EVE induced increase in level of spinal block has not been researched till date. We proposed to determine the MEV of normal saline required for EVE induced increase in post-spinal block sensory level.

MATERIALS AND METHODS

This prospective sequential allocation study was conducted in consenting adult males after institutional ethical committee approval scheduled for lower limb surgery under combined spinal epidural (CSE) anesthesia, who had an inadequate level of sensory block. Herein, an inadequate level was defined as lower than T10 at 10 min after the intrathecal injection, with no ascent for two consecutive readings taken 2 min apart. The EVE was performed with normal saline injected through epidural catheter, and was considered successful if the level of sensory block increased by two or more dermatomal segments within 5 min of the injection. The volume of normal saline for EVE was decided by using the up-and-down method, with the first patient receiving 10 mL and a dosing interval of 1 mL in subsequent patients. The analysis was done using the formula of Dixon and Massey, which enabled calculation of the MEV with 95% CI. Quantitative parametric data is represented as mean ± SD and nonparametric data as median (range).

RESULTS AND CONCLUSION

The MEV of normal saline to raise the level of sensory block by two or more dermatomal segments within 5 min of EVE is 7.4 mL (95% CI: 5.5-9.9 mL).

Combined spinal epidural and epidural volume extension: Interaction of patient position and hyperbaric bupivacaine

BACKGROUND

Previous trials have documented failure of block augmentation with epidural volume extension, when applied after the intrathecal injection of hyperbaric bupivacaine was made in sitting position. However, there is no study comparing the effect of change in patient position during block performance, on the results of epidural volume extension.

MATERIALS AND METHODS

The study was conducted in two parts in American Society of Anesthesiologists physical status I or II parturients scheduled for elective cesarean section under regional anesthesia. In the first part, 28 patients were randomized to one of the two groups, depending on whether epidural volume extension was applied following the block in sitting (group SE) or lateral position (group LE) (n=14 each). In the second part of the study another 28 patients were recruited and randomized to receive the block in sitting (group S) or lateral (group L) position (n=14 each), without epidural volume extension. All patients received combined spinal epidural block using needle-through-needle technique with intrathecal injection of 9 mg hyperbaric bupivacaine (0.5%) and 10 μg fentanyl. Epidural volume extension was performed using 5 ml normal saline in groups SE and LE.

RESULTS

In the first part of the study, the maximum sensory block level was higher in group LE vs. SE (P<0.05). In the second part of the study, no significant difference was seen in the maximum sensory level between group S and group L (P>0.05).

CONCLUSIONS

If epidural volume extension is being applied with intention of rapid extension of sensory block when hyperbaric bupivacaine has been injected intrathecally, the combined spinal epidural block should be performed in lateral position rather than in the sitting position.

[Combined spinal-epidural anaesthesia for urgent Hartmann's procedure]

A 46- year old patient without previous history of general anaesthesia was admitted for urgent Hartman's procedure. The suspected tumor of sigmoid colon caused the obstructive ileus with extreme abdominal distension and threatened colon perforation. After induction of anaesthesia and adequate muscle relaxation it appeared that endotrh ileus because of possible regurgitation and aspiration.