Dose-Response Study of Phenylephrine for Preventing Spinal-Induced Hypotension During Cesarean Delivery with Combined Spinal-Epidural Anesthesia Under the Effect of Prophylactic Intravenous Ondansetron.

Background: Ondansetron reduces the median effective dose (ED50) of prophylactic phenylephrine to prevent spinal-induced hypotension (SIH) during cesarean delivery. However, the exact dose response of phenylephrine in combination with prophylactic ondansetron for preventing SIH is unknown. Therefore, this study aimed to determine the dose-response of phenylephrine to prevent SIH in cesarean delivery when 4 mg of ondansetron was used as a preventive method. Methods: A total of 80 parturients were enrolled and divided randomly into four groups (n = 20 in each group) who received either 0.2, 0.3, 0.4, or 0.5 µg/kg/min of prophylactic phenylephrine. Ten minutes before the initiation of spinal induction, 4 mg prophylactic ondansetron was administered. The effective dose of prophylactic phenylephrine was defined as the dose required to prevent hypotension after the period of intrathecal injection and up to neonatal delivery. The ED50 and ED90 of prophylactic phenylephrine and 95% confidence intervals (95% CI) were calculated using probit analysis. Results: The ED50 and ED90 for prophylactic phenylephrine to prevent SIH were 0.25 (95% CI, 0.15 to 0.30), and 0.45 (95% CI, 0.39 to 0.59) µg/kg/min, respectively. No significant differences were observed in the side effects and neonatal outcomes between the four groups. Conclusion: The administration of 4 mg of prophylactic ondansetron was associated with an ED50 of 0.25 (95% CI, 0.15~0.30) and ED90 of 0.45 (95% CI, 0.39~0.59) µg/kg/min for phenylephrine to prevent SIH.

The Bezold-Jarisch reflex and anaesthesia.

Spinal anaesthesia is considered an effective and safe method for providing pain relief during procedures below the waist. However, in a small subset of patients, life-threatening vasovagal reactions may develop leading to severe bradycardia and hypotension or ultimately asystole and complete circulatory collapse. Early recognition and prompt treatment of this condition can be lifesaving as illustrated in this case report where the patient developed asystole for ten seconds shortly after placing the spinal anaesthetic.

Evaluation of neuraxial analgesia on outcomes for patients undergoing robot assisted abdominal surgery.

STUDY OBJECTIVE: Following robot assisted abdominal surgery, the pain can be moderate in severity. Neuraxial analgesia may decrease the activity of the detrusor muscle, reduce the incidence of bladder spasm and provide effective somatic and visceral analgesia. In this systematic review, we assessed the role of neuraxial analgesia in robot assisted abdominal surgery. DESIGN: Systematic review. SETTINGS: Robot assisted abdominal surgery. PATIENTS: Adults. INTERVENTIONS: Subsequent to a search of the electronic databases, observational studies and randomized controlled trials that assessed the effect of neuraxial analgesia instituted at induction of anesthesia or intraoperatively in adult and robot assisted abdominal surgery were considered for inclusion. The outcomes of observational studies as well as randomized controlled trials which were not subjected to meta-analysis were presented in descriptive terms. Meta-analysis was conducted if an outcome of interest was reported by two or more randomized controlled trials. MAIN RESULTS: We included 19 and 11 studies that investigated spinal and epidural analgesia in adults, respectively. The coprimary outcomes were the pain score at rest at 24 h and the cumulative intravenous morphine consumption at 24 h. Spinal analgesia with long acting neuraxial opioid did not decrease the pain score at rest at 24 h although it reduced the cumulative intravenous morphine consumption at 24 h by a mean difference (95%CI) of 14.88 mg (-22.13--7.63; p < 0.0001, I2 = 50%) with a low and moderate quality of evidence, respectively, on meta-analysis of randomized controlled trials. Spinal analgesia with long acting neuraxial opioid had a beneficial effect on analgesic indices till the second postoperative day and a positive influence on opioid consumption up to and including the 72 h time point. The majority of studies demonstrated the use of spinal analgesia with long acting neuraxial opioid to lead to no difference in the incidence of postoperative nausea and vomiting, and the occurrence of pruritus was found to be increased with spinal analgesia with long acting neuraxial opioid in recovery but not at later time points. No difference was revealed in the incidence of urinary retention. The evidence in regard to the quality of recovery-15 score at 24 h and hospital length of stay was not fully consistent, although most studies indicated no difference between spinal analgesia and control for these outcomes. Epidural analgesia in robot assisted abdominal surgery was shown to decrease the pain on movement at 12 h but it had not been studied with respect to its influence on the pain score at rest at 24 h or the cumulative intravenous morphine consumption at 24 h. It did not reduce the pain on movement at later time points and the evidence related to the hospital length of stay was inconsistent. CONCLUSIONS: Spinal analgesia with long acting neuraxial opioid had a favourable effect on analgesic indices and opioid consumption, and is recommended by the authors, but the evidence for spinal analgesia with short acting neuraxial opioid and epidural analgesia was limited.

Super-refractory status epilepticus, rhabdomyolysis, central hyperthermia and cardiomyopathy attributable to spinal anesthesia: a case report and review of literature.

BACKGROUND: There are only six past reports of super-refractory status epilepticus induced by spinal anesthesia. None of those patients have died. Only < 15 mg of bupivacaine was administered to all six of them and to our case. Pathophysiology ensuing such cases remains unclear. CASE PRESENTATION: A 27 year old gravida 2, para 1, mother at 37 weeks of gestation came to the operating theater for an elective cesarean section. She had no significant medical history other than controlled hypothyroidism and one episode of food allergy. Her current pregnancy was uneventful. Her American Society of Anesthesiologists (ASA) grade was 2. She underwent spinal anesthesia and adequate anesthesia was achieved. After 5-7 min she developed a progressive myoclonus. After delivery of a healthy baby, she developed generalized tonic clonic seizures that continued despite the induction of general anesthesia. She had rhabdomyolysis, one brief cardiac arrest and resuscitation, followed by stress cardiomyopathy and central hyperthermia. She died on day four. There were no significant macroscopic or histopathological changes in her brain that explain her super refractory status epilepticus. Heavy bupivacaine samples of the same batch used for this patient were analyzed by two specialized laboratories. National Medicines Quality Assurance Laboratory of Sri Lanka reported that samples failed to confirm United States Pharmacopeia (USP) dextrose specifications and passed other tests. Subsequently, Therapeutic Goods Administration of Australia reported that the drug passed all standard USP quality tests applied to it. Nonetheless, they have detected an unidentified impurity in the medicine. CONCLUSIONS: After reviewing relevant literature, we believe that direct neurotoxicity by bupivacaine is the most probable cause of super-refractory status epilepticus. Super-refractory status epilepticus would have led to her other complications and death. We discuss probable patient factors that would have made her susceptible to neurotoxicity. The impurity in the drug detected by one laboratory also would have contributed to her status epilepticus. We propose several possible mechanisms that would have led to status epilepticus and her death. We discuss the factors that shall guide investigators on future such cases. We suggest ways to minimize similar future incidents. This is an idiosyncratic reaction as well.

Randomized Double-Blinded Comparison of Intermittent Boluses Phenylephrine and Norepinephrine for the Treatment of Postspinal Hypotension in Patients with Severe Pre-Eclampsia During Cesarean Section.

Background: Norepinephrine has fewer negative effects on heart rate (HR) and cardiac output (CO) for treating postspinal hypotension (PSH) compared with phenylephrine during cesarean section. However, it remains unclear whether fetuses from patients with severe pre-eclampsia could benefit from the superiority of CO. The objective of this study was to compare the safety and efficacy of intermittent intravenous boluses of phenylephrine and norepinephrine used in equipotent doses for treating postspinal hypotension in patients with severe pre-eclampsia during cesarean section. Methods: A total of 80 patients with severe pre-eclampsia who developed PSH predelivery during cesarean section were included. Eligible patients were randomized at a 1:1 ratio to receive either phenylephrine or norepinephrine for treating PSH. The primary outcome was umbilical arterial pH. Secondary outcomes included other umbilical cord blood gas values, Apgar scores at 1 and 5 min, changes in hemodynamic parameters including CO, mean arterial pressure (MAP), HR, stroke volume (SV), and systemic vascular resistance (SVR), the number of vasopressor boluses required, and the incidence of bradycardia, hypertension, nausea, vomiting, and dizziness. Results: No significant difference was observed in umbilical arterial pH between the phenylephrine and norepinephrine groups (7.303±0.38 vs 7.303±0.44, respectively; P=0.978). Compared with the phenylephrine group, the overall CO (P=0.009) and HR (P=0.015) were greater in the norepinephrine group. The median [IQR] total number of vasopressor boluses required was comparable between the two groups (2 [1 to 3] and 2 [1 to 3], respectively; P=0.942). No significant difference was found in Apgar scores or the incidence of maternal complications between groups. Conclusion: A 60 µg bolus of phenylephrine and a 4.5 µg bolus of norepinephrine showed similar neonatal outcomes assessed by umbilical arterial pH and were equally effective when treating PSH during cesarean section in patients with severe pre-eclampsia. Norepinephrine provided a higher maternal CO and a lower incidence of bradycardia.

Efficacy and Safety of Pericapsular Nerve Group Block for Hip Fracture Surgery under Spinal Anesthesia: A Meta-Analysis.

Objective: To evaluate the effectiveness and safety of pericapsular nerve group (PENG) block for hip fracture surgery under spinal anesthesia. Methods: This meta-analysis was registered on INPLASY (INPLASY202270005). PubMed, Embase, Cochrane, CNKI, and Wanfang databases were searched to collect the randomized controlled trials of the PENG block applied to hip fracture surgery in the setting of spinal anesthesia, with the search period from inception to 1 May 2023. Two independent researchers gradually screened the literature, evaluated the quality, extracted the data, and eventually pooled data using RevMan 5.4. Results: Fifteen articles with 890 patients were enrolled. The combined results showed that the PENG block reduced pain scores during position placement (SMD = -0.35; 95% CI [-0.67, 0.02]; P=0.04; I2 = 0%). Subgroup analyses showed that compared to the unblocked group, the PENG block reduced pain scores at 12 h, 24 h, and 48 h postoperatively. The incidence of postoperative hypokinesia was reduced (RR = 0.11; 95% CI [0.01, 0.86]; P=0.04; I2 = 0.00%). The time to first walking was advanced (SMD = -0.90; 95% CI [-1.17, 0.63]; P < 0.00001; I2 = 0%). Conclusion: The PENG block can reduce postoperative pain and pain during spinal anesthesia positioning, which is helpful to improve the operability and comfort of spinal anesthesia and facilitate postoperative muscle strength recovery and early activity.

Bupivacaine-fentanyl isobaric spinal anesthesia reduces the risk of ICU admission in elderly patients undergoing lower limb orthopedic surgery.

BACKGROUND: To evaluate if bupivacaine-fentanyl isobaric spinal anesthesia could reduce the risk of ICU admission compared with general anesthesia in elderly patients undergoing lower limb orthopedic surgery. METHODS: This study comprised a retrospective review of all lower limb orthopedic surgeries performed at our hospital between January 2013 and December 2019. According to anesthesia methods, patients were divided into the spinal anesthesia group (n = 1,728) and the general anesthesia group (n = 188). The primary outcome evaluated was the occurrence of ICU admission. Secondary outcomes included hemodynamic changes, postoperative complications, and mortality. RESULTS: Repeated measure analysis of variance indicated that the difference between the two groups in the systolic blood pressure (SBP) was not significant before anesthesia (T0), immediately after anesthesia (T1), and before leaving the operation room (T8) (P > 0.05), but significant (P < 0.01) from 5 min after anesthesia (T2) to after operation (T7). The proportions of ICU admission (6.4% vs. 23.8%, P < 0.01) and unplanned intubation (0.1% vs. 3.8%, P < 0.01) were significantly lower in the spinal anesthesia group compared with those in the general anesthesia group. Multivariate logistic regression revealed that after controlling for potential confounding factors, the odds of ICU admission for patients in the spinal anesthesia group was 0.240 times (95% CI 0.115-0.498; P < 0.01) than those in the general anesthesia group. CONCLUSIONS: Bupivacaine-fentanyl isobaric spinal anesthesia significantly reduced the risk of ICU admission and unplanned intubation, and provided better intraoperative hemodynamics in elderly patients undergoing lower limb orthopedic surgery. TRIAL REGISTRATION: This study has been registered in the Chinese Clinical Trial Registry (ChiCTR2000033411).

Norepinephrine versus phenylephrine on cerebral tissue oxygen saturation during prophylactic infusion to prevent spinal hypotension for Caesarean birth.

BACKGROUND: Phenylephrine may cause a reduction in maternal cerebral tissue oxygen saturation (SctO2) during Caesarean birth to prevent spinal hypotension; however, the effect of norepinephrine has not been assessed. We hypothesized that norepinephrine was more effective than phenylephrine in maintaining SctO2 when preventing spinal hypotension during Caesarean birth. METHODS: We conducted a randomized, double-blind, controlled study. Sixty patients were randomly assigned to prophylactic norepinephrine or phenylephrine to maintain blood pressure during spinal anesthesia for Caesarean birth. SctO2, systolic blood pressure, and heart rate were recorded. The primary outcome was the incidence of a 10% reduction of intraoperative SctO2 from baseline or more during Caesarean birth. RESULTS: The norepinephrine group had a lower incidence of more than 10% reduction of intraoperative SctO2 from baseline than that of the phenylephrine group (13.3% vs 40.0%, P = .02). The change in SctO2 after 5 minutes of norepinephrine infusion was higher than that after phenylephrine infusion (-3.4 ±â€…4.7 vs -6.2 ±â€…5.6, P = .04). The change in SctO2 after 10 minutes of norepinephrine infusion was higher than that after phenylephrine infusion (-2.5 ±â€…4.4 vs -5.4 ±â€…4.6, P = .006). The norepinephrine group showed greater left- and right-SctO2 values than the phenylephrine group at 5 to 10 minutes. However, the change in systolic blood pressure was comparable between the 2 groups. CONCLUSION: Norepinephrine was more effective than phenylephrine in maintaining SctO2 when preventing spinal hypotension during Caesarean birth. However, the changes in clinical outcomes caused by differences in SctO2 between the 2 medications warrant further studies.

Is crystalloid co-loading necessary to prevent spinal hypotension during elective cesarean delivery? A randomized double-blind trial.

BACKGROUND: Hypotension is common during spinal anesthesia for cesarean delivery. Preventive strategies include fluid loading and phenylephrine. We hypothesized that if prophylactic phenylephrine infusion is used, omission of fluid loading would be non-inferior to fluid co-loading in maintaining cardiac output. We assumed that if there was a difference, the increase in cardiac output would be greater in the no-loading than in the co-loading group. METHODS: Term pregnant women scheduled for elective cesarean delivery were randomized to receive 1 L crystalloid co-loading or maintenance fluids only. Phenylephrine was titrated to maintain blood pressure. Changes in cardiac output following spinal anesthesia were the primary outcome. The study was powered as a non-inferiority trial, allowing the no-loading arm to have a 50% greater change in cardiac output. Heart rate, dose of phenylephrine, occurrence of nausea and vomiting, Apgar scores and neonatal acid base status were secondary outcomes. RESULTS: Data from 63 women were analyzed. In contrast to our hypothesis, there was 33% less increase in cardiac output with no loading (ratio 0.67, 95% CI 0.15 to 1.36), and 60% greater reduction of cardiac output with no loading (ratio 1.6, 95% CI 1.0 to 2.7). Total dose of phenylephrine was higher in the no-loading group. There may be a less favorable neonatal acid base status without volume loading. CONCLUSION: Omission of crystalloid co-loading leads to a decrease in cardiac output which has a potentially unfavorable impact on neonatal acid base status. We conclude that crystalloid co-loading may be useful in the presence of phenylephrine infusion.

Non-pharmacological treatments for shivering post neuraxial anaesthesia for caesarean section: a scoping review.

BACKGROUND: Shivering occurs more frequently for women having caesarean section under neuraxial anaesthesia compared to other patient groups and causes an increase in pain and interrupts bonding with her newborn. AIM: This study aimed to report the evidence on non-pharmacological methods to treat shivering, defined as uncontrollable shaking, because of being cold, frightened, or excited, post neuraxial anaesthesia; the use of local anaesthesia inserted around the nerves of the central nervous system such as spinal anaesthesia and epidural in women having a caesarean section. METHODS: A scoping review was conducted using six electronic health databases that were searched with no restrictions placed on language, date, or study type. FINDINGS: Of the 1399 studies identified, following screenings only one study was deemed suitable for inclusion. The study, a randomised controlled trial, compared forced air warming blankets (intervention) with the usual care of warmed cotton blankets (control) and its impact on maternal and newborn outcomes. The only statistically significant difference found was the perceived thermal comfort of the mother. DISCUSSION: Non-pharmacological treatments for shivering are underrepresented in the literature; only one study identified where the impact of active warming was compared to warmed cotton blankets (usual care) for the measures of: oral temperature; degree of shivering; and thermal comfort pain scores. There was a decline in temperature in both groups at odds with some women reporting feeling too warm such that they asked for the active warmer to be turned down. CONCLUSION: Social engagement strategies are interventions that send a signal of safety to the nervous system leading to a sense of calm and wellbeing and have biological plausibility and warrant evaluation. Recommendations for further research: design a robust study to test the effectiveness of social engagement strategies on shivering for women having caesarean section under neuraxial anaesthesia.

Effect of phenylephrine rescue injection on hypotension after spinal anaesthesia for caesarean delivery when guided by both heart rate and SBP during an early warning window: A randomised controlled trial.

BACKGROUND: Spinal anaesthesia is now the most common technique for caesarean delivery. However, because of the intermittent nature of noninvasive blood pressure (NIBP) measurements, maternal blood pressure may become hypotensive between the measurements. There is thus an inbuilt delay before the anaesthesiologist can intervene to counteract the hypotension. Based on the principle that changes in blood pressure can induce compensatory changes in the heart rate (HR), combining the NIBP with real-time HR, we designed two warning windows to predict hypotension and hypertension. OBJECTIVE: To evaluate whether phenylephrine administration guided by these warning windows would help maintain haemodynamic stability. SETTING: A teaching hospital. DESIGN: A randomised controlled trial. PATIENTS: One hundred and ten pregnant women scheduled for elective caesarean delivery were enrolled, from which, after exclusions, 86 were eligible for the study. INTERVENTIONS: All eligible patients received a continuous intravenous infusion of phenylephrine as soon as spinal anaesthesia was initiated. Thereafter, patients were randomly assigned to two groups. In the test group (Win-Group): rescue phenylephrine administration was triggered by an early warning window of HR above 100 beats per minute (bpm) and SBP 90 to 110 mmHg; pausing the infusion phenylephrine was triggered by a HR lower than 60 bpm and SBP greater than 90 mmHg. In the control group, phenylephrine was guided by BP only when it appeared on the monitor: SBP less than 90 mmHg was the trigger for administering rescue phenylephrine; SBP greater than 110 mmHg was the trigger for pausing the phenylephrine infusion. MAIN OUTCOME MEASURES: The primary outcome was incidence of hypotension. Secondary outcomes were the incidence of hypertension and other adverse haemodynamic events. RESULTS: The incidence of hypotension was significantly lower in the Win-Group than in the BP-Group (27.8 vs. 66.7%, P  = 0.001). The minimum SBP was significantly higher in Win-Group than in BP-Group (93.9 ±â€Š9.49 vs. 86.7 ±â€Š11.16 mmHg, P   =  0.004). There was no significant difference in the incidence of hypertension between groups. CONCLUSION: After spinal anaesthesia for caesarean delivery, when phenylephrine infusion is guided by HR along with BP from a warning window it effectively reduces the incidence of hypotension without any significant effect on incidence of hypertension. TRIAL REGISTRATION: Chictr.org.cn; Identifier: ChiCTR 2100041812.

Failed spinal anesthesia for cesarean delivery: prevention, identification and management.

PURPOSE OF REVIEW: There is an increasing awareness of the significance of intraoperative pain during cesarean delivery. Failure of spinal anesthesia for cesarean delivery can occur preoperatively or intraoperatively. Testing of the neuraxial block can identify preoperative failure. Recognition of the risk of high neuraxial block in repeat spinal in case of preoperative failure is important. RECENT FINDING: Knowledge of risk factors for block failure facilitates prevention by selecting the most appropriate neuraxial procedure, adequate intrathecal doses and choice of technique. Intraoperative pain is not uncommon, and neither obstetricians nor anesthesiologists can adequately identify intraoperative pain. Early intraoperative pain should be treated differently from pain towards the end of surgery. SUMMARY: Block testing is crucial to identify preoperative failure of spinal anesthesia. Repeat neuraxial is possible but care must be taken with dosing. In this situation, switching to a combined spinal epidural or an epidural technique can be useful. Intraoperative pain must be acknowledged and adequately treated, including offering general anesthesia. Preoperative informed consent should include block failure and its management.

Oral midodrine for prophylaxis against post-spinal anesthesia hypotension during hip arthroplasty in elderly population: a randomized controlled trial.

BACKGROUND: We aimed to evaluate the efficacy of midodrine as a prophylaxis against post-spinal hypotension in elderly patients undergoing hip arthroplasty. METHODS: This randomized controlled trial included elderly patients undergoing hip arthroplasty under spinal anesthesia. Ninety minutes before the procedure, patients were randomized to receive either 5-mg midodrine or placebo (metoclopramide). After spinal anesthesia, mean arterial pressure (MAP) and heart rate were monitored every 2 min for 20 min then every 5 min until the end of the procedure. Post-spinal hypotension (MAP < 80% baseline) was treated with 10 mg ephedrine. The primary outcome was intraoperative ephedrine consumption. Secondary outcomes were the incidence of post-spinal hypotension, bradycardia, and hypertension (MAP increased by > 20% of the baseline reading). RESULTS: We analyzed 29 patients in the midodrine group and 27 in the control group. The intraoperative ephedrine consumption was lower in the midodrine group than in the control group (median [quartiles]: 10 [0, 30] mg versus 30 [20, 43] mg, respectively, P-value: 0.002); and the incidence of intraoperative hypotension was lower in the midodrine group than that in the control group. The incidence of hypertension and bradycardia were comparable between the two groups. CONCLUSION: The use of 5 mg oral midodrine decreased the vasopressor requirements and incidence of hypotension after spinal anesthesia for hip surgery in elderly patients. CLINICAL TRIAL REGISTRATION: This study was registered on September 22, 2022 at clinicaltrials.gov registry, NCT05548985, URL: https://classic. CLINICALTRIALS: gov/ct2/show/NCT05548985 .

Is barbotage in central neuraxial blockade a ritual habit or an evidence-based technique?

Barbotage refers to the repeated aspiration and re-injection of CSF following injection of local anaesthetic into the intrathecal space, and its practice varies among anaesthetists. This article reviews the evidence for and against this practice to alter block dynamics following intrathecal injection reserved for spinal anaesthesia.

Aseptic meningitis following spinal anaesthesia: An uncommon and challenging diagnosis.

Drug-induced aseptic meningitis (DIAM) or chemical meningitis following spinal anaesthesia has rarely been reported. DIAM is caused by meningeal inflammation due to intrathecally administered drugs or secondary to systemic immunological hypersensitivity. We hereby present a case of a young adult with aseptic meningitis following neuraxial anaesthesia possibly provoked by bupivacaine. The initial cerebrospinal fluid (CSF) picture revealed neutrophilic pleocytosis and normal glycorrhachia. CSF culture was negative. The patient was put on invasive mechanical ventilation and started on intravenous antibiotics. There was a rapid improvement in clinical condition without any residual neurological deficit within the next few days. Aseptic meningitis following neuraxial anaesthesia can be prevented by strict aseptic protocols and careful inspection of visible impurities while administering the intrathecal drug. Detailed history taking, clinical examination, and focused investigations can distinguish between bacterial and chemical meningitis. Appropriate diagnosis of this entity may guide the treatment regimen, reducing hospital stay and cost.

Risk factors of more severe hypotension after spinal anesthesia for cesarean section.

BACKGROUND: The aim of this study was to examine the risk factors associated with the use of vasopressors to prevent hypotension that occurs after spinal anesthesia during cesarean section. Although the prophylactic use of vasopressors is already suggested as routine care in many parts of the world, the occurrence of spinal anesthesia-induced hypotension (SAIH) is still common in parturients. METHODS: This retrospective study included parturients receiving elective cesarean deliveries under spinal anesthesia from April 2016 to March 2020. Risk factors related to ephedrine dosage were analyzed using a hurdle model, and risk factors related to SAIH were further analyzed with logistic regression. RESULTS: Five risk factors, namely maternal body mass index (BMI, p < 0.001), baseline systolic blood pressure (SBP, p < 0.001), baseline heart rate (HR, p = 0.047), multiparity ( p = 0.003), and large fetal weight ( p = 0.005) were significantly associated with the requirement for ephedrine. Furthermore, a higher ephedrine dosage was significantly associated with maternal BMI ( p < 0.001), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p = 0.027), large fetal weight ( p = 0.030), maternal age ( p = 0.009), and twin pregnancies ( p < 0.001). Logistic regression analysis also showed that the same five risk factors-maternal BMI ( p = 0.030), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p < 0.001), and large fetal weight ( p < 0.001)-were significantly associated with SAIH, even in cases where vasopressors were administered. CONCLUSION: These findings can be useful for clinicians when deciding the dose of prophylactic ephedrine or phenylephrine to prevent SAIH.

Comparison of the Effect of Landmark-Based Midline and Paramedian Approaches on Spinal Anesthesia-Related Complications in Adult Patients: A Meta-Analysis of Randomized Controlled Trials.

Background and Objectives: Spinal anesthesia is widely used in various types of surgery. However, several complications can occur afterward. This study aimed to identify differences in the incidence of anesthesia-related complications according to the approach methods (midline versus paramedian) for landmark-based spinal anesthesia. Materials and Methods: We searched electronic databases, including PubMed, EMBASE, CENTRAL, Scopus, and Web of Science, for eligible randomized controlled trials. The primary outcome was post-dural puncture headache (PDPH) incidence, and secondary outcomes were low back pain (LBP) incidence and success rate in the first trial of spinal anesthesia. We estimated the odds ratio (OR) with 95% confidence intervals (CI) using a random-effects model. Results: In total, 2280 patients from 13 randomized controlled trials were included in the final analysis. The incidence rates of PDPH were 5.9% and 10.4% in the paramedian and midline approach groups, respectively. The pooled effect size revealed that the incidence of PDPH (OR: 0.43, 95% CI [0.22-0.83]; p = 0.01; I2 = 53%) and LBP (OR: 0.27, 95% CI [0.16-0.44]; p < 0.001; I2 = 16%) decreased, and the success rate in the first attempt was higher (OR: 2.30, 95% CI [1.36-3.87]; p = 0.002; I2 = 35%) with the paramedian than with the midline approach. Conclusions: Paramedian spinal anesthesia reduced PDPH and LBP and increased the success rate of the first attempt.

Isolated bilateral tinnitus after spinal anesthesia: A case report.

Rarely, endolymphatic hydrops may occur after spinal anesthesia due to the perforation of the dural membrane and a decrease in cerebrospinal fluid pressure. Consequently, auditory complications such as tinnitus and hearing loss may arise. Tinnitus can be accompanied by headache and hearing loss. In this case report, isolated bilateral tinnitus, which occurred in the early intraoperative period and spontaneously regressed in a patient who underwent bilateral tubal ligation under spinal anesthesia, is presented.

The Incidence and Predictors of Failed Spinal Anesthesia After Intrathecal Injection of Local Anesthetic for Cesarean Delivery: A Single-Center, 9-Year Retrospective Review.

BACKGROUND: The incidence of failed spinal anesthesia varies widely in the obstetric literature. Although many risk factors have been suggested, their relative predictive value is unknown. The primary objective of this retrospective cohort study was to determine the incidence of failed spinal anesthesia for cesarean deliveries at a tertiary care obstetric hospital, and its secondary objectives were to identify predictors of failed spinal anesthesia in the obstetrics population and quantify their relative importance in a predictive model for failure. METHODS: With local institutional ethics committee approval, a retrospective review of our hospital database identified the incidence of failed spinal anesthesia for 5361 cesarean deliveries between 2010 and 2019. We performed a multivariable analysis to assess the association of predictors with failure and a dominance analysis to assess the importance of each predictor. RESULTS: The incidence of failed spinal anesthesia requiring an alternative anesthetic was 2.1%, with conversion to general anesthesia occurring in 0.7% of surgeries. Supplemental analgesia or sedation was provided to an additional 2.0% of women. The most important predictors of a failed spinal anesthetic were previous cesarean delivery (odds ratio [OR], 11.33; 95% confidence interval [CI], 7.09-18.20; P < .001), concomitant tubal ligation (OR, 8.23; 95% CI, 3.12-19.20; P < .001), lower body mass index (BMI) (kg·m -2 , OR, 0.94; 95% CI, 0.90-0.98; P = .005), and longer surgery duration (minutes, OR, 1.02; 95% CI, 1.01-1.03; P = .006). Previous cesarean delivery was the most significant risk factor, contributing to 9.6% of the total 17% variance predicted by all predictors examined. CONCLUSIONS: Spinal anesthesia failed to provide a pain-free surgery in 4.1% of our cesarean deliveries. Previous cesarean delivery was the most important predictor of spinal failure. Other important predictors included tubal ligation, lower BMI, and longer surgery duration.