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.

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.

The Effect of Warmed Serum on Shivering and Recovery Period of Patients Under General and Spinal Anesthesia: A Randomized Clinical Trial.

PURPOSE: Postoperative hypothermia followed by shivering is a common phenomenon in patients undergoing surgery under anesthesia, and should be prevented and treated in postoperative patient care units. This study was conducted to investigate the effect of warmed serum injection on postoperative shivering and recovery period of patients operated under general and spinal anesthesia. DESIGN: In this clinical trial, patients to be operated on under general and spinal anesthesia were randomly assigned into two groups of test and control. In the test group, patients received warmed intravenous fluids and blood products. All patients were monitored to record vital signs, incidences of hypothermia and shivering, and recovery period. METHODS: The collected data were analyzed with repeated measures analysis of variance to detect significant differences between groups and significant changes within groups over time. FINDINGS: The incidence of nausea, vomiting, and shivering in the intervention and control groups was (4.7%, 42%), (2.8%, 16.8%), and (6.6%, 43%), respectively. Patients in the intervention group had higher body temperature than the control group (<0.001). Also, patients under spinal anesthesia had higher body temperature than patients under general anesthesia (<0.001). Blood pressure reduction was also significantly higher in the control group than in the intervention group. The patients who received warm intravenous serum, and especially those who had received spinal anesthesia spent less time in the recovery room (<0.001). CONCLUSIONS: The use of warmed intravenous serum increased the patients' core temperature, reduced their postoperative shivering, and shortened their recovery period. Considering the potential risks associated with hypothermia, using such methods for hypothermia prevention can be highly effective in preventing shivering and prolongation of the recovery period and other potential complications. Anesthesia specialists and technicians are therefore encouraged to use this method as a preventive measure.

Subclavian vein ultrasound-guided fluid management to prevent post-spinal anesthetic hypotension during cesarean delivery: a randomized controlled trial.

BACKGROUND: Hypotension frequently occurs after spinal anesthesia during cesarean delivery, and fluid loading is recommended for its prevention. We evaluated the efficacy of subclavian vein (SCV) ultrasound (US)-guided volume optimization in preventing hypotension after spinal anesthesia during cesarean delivery. METHODS: This randomized controlled study included 80 consecutive full-term parturients scheduled for cesarean delivery under spinal anesthesia. The women were randomly divided into the SCVUS group, with SCVUS analysis before spinal anesthesia with SCVUS-guided volume management, and the control group without SCVUS assessment. The SCVUS group received 3 mL/kg crystalloid fluid challenges repeatedly within 3 min with a 1-min interval based on the SCV collapsibility index (SCVCI), while the control group received a fixed dose (10 mL/kg). Incidence of post-spinal anesthetic hypotension was the primary outcome. Total fluid volume, vasopressor dosage, changes in hemodynamic parameters, maternal adverse effects, and neonatal status were secondary outcomes. RESULTS: The total fluid volume was significantly higher in the control group than in the SCVUS group (690 [650-757.5] vs. 160 [80-360] mL, p < 0.001), while the phenylephrine dose (0 [0-40] vs. 0 [0-30] µg, p = 0.276) and incidence of post-spinal anesthetic hypotension (65% vs. 60%, p = 0.950) were comparable between both the groups. The incidence of maternal adverse effects, including nausea/vomiting and bradycardia (12.5% vs. 17.5%, p = 0.531 and 7.5% vs. 5%, p = 1.00, respectively), and neonatal outcomes (Apgar scores) were comparable between the groups. SCVCI correlated with the amount of fluid administered (R = 0.885, p < 0.001). CONCLUSIONS: SCVUS-guided volume management did not ameliorate post-spinal anesthetic hypotension but reduced the volume of the preload required before spinal anesthesia. Reducing preload volume did not increase the incidence of maternal and neonatal adverse effects nor did it increase the total vasopressor dose. Moreover, reducing preload volume could relieve the heart burden of parturients, which has high clinical significance. CLINICAL TRIAL REGISTRATION: The trial was registered with the Chinese Clinical Trial Registry at chictr.org.cn (registration number, ChiCTR2100055050) on December 31, 2021.

Tranexamic acid-associated intrathecal toxicity during spinal anaesthesia: A narrative review of 22 recent reports.

Therapeutic use of tranexamic acid (TXA) to minimise blood loss is common during a wide range of surgical procedures. This review aims to explore the clinical features of the accidental intrathecal administration of TXA and to identify contributory factors that might prevent future incidents. The author searched published reports of accidental intrathecal administration of TXA using Medline and Google Scholar databases from July 2018 to September 2022, including error reports in any language but excluding errors via nonintrathecal routes. The human factors analysis classification system (HFACS) framework was used to examine and classify the human and systemic factors that contributed to the errors. Twenty-two errors of accidental intrathecal administration were reported during the search period. The analysis showed that the outcome was death in eight patients (36%) and permanent harm in four (19%). The fatality rate was higher among female individuals (6/13 versus 2/8 male individuals). Two-thirds of errors (15/22) occurred during orthopaedic surgery (10) and lower segment caesarean sections (5). Nineteen of 21 patients developed refractory or super refractory status epilepticus, requiring mechanical ventilation and intensive care for 3 days to 3 weeks for those who survived the initial few hours. Severe sympathetic stimulation resulting in refractory ventricular arrhythmias was the final event in some patients, with death within a few hours. Lack of familiarity with clinical characteristics caused delayed diagnosis or confusion with other clinical conditions. A proposed plan to manage intrathecal TXA toxicity is presented, including immediate cerebrospinal fluid lavage; however, there is no specific approach. The HFACS suggested mistaking look-alike TXA ampoules for local anaesthetic was the predominant cause. The author concludes that inadvertent intrathecal TXA is associated with mortality or permanent harm in more than 50% of patients. The HFACS demonstrates that all errors are preventable.

Integrative review of non-pharmacological intervention and multidimensional evaluation for intraoperative anxiety under spinal anaesthesia.

INTRODUCTION: Patients under spinal anaesthesia experience high levels of anxiety during surgery. Clinical nurses tried to manage patient's anxiety under spinal anaesthesia using non-pharmacological interventions for its benefit. Thus, it is required to identify comprehensive evidences of various non-pharmacological interventions and of how to measure anxiety under spinal anaesthesia. AIMS: This study aims to review current research on the non-pharmacological interventions to relieve intraoperative anxiety under spinal anaesthesia and to identify subjective and objective measures of intraoperative anxiety under spinal anaesthesia. METHODS: Wittemore and Knafl's integrative review methodology was used. Researchers conducted five scientific rigor steps; problem identification, searching literature, evaluation of literature, analysis of literature and presentation of results. The PRISMA checklist was used. To evaluate the level of evidence, critical appraisal tools of Joanna Briggs Institute were used. RESULTS: Eleven studies were included in this integrative review. Delivering music is the most frequently used as non-pharmacological intervention by researchers. They tried to manage intraoperative anxiety under spinal anaesthesia with using diverse genre and application of music. In addition, dry cupping method, progressive muscle relaxation (PMR) exercise and virtual reality (VR) goggles were used in included studies. Researchers measured intraoperative anxiety under spinal anaesthesia with objective or subjective way. The State-Trait Anxiety Inventory and visual analogue scale were used as subjective method to approach intraoperative anxiety. In contrary, researchers tried to obtain objective evidence of intraoperative anxiety with vital signs, cortisol, blood glucose, alpha-amylase and adrenocorticotropic hormone. CONCLUSION: Various types of non-pharmacological interventions are effective to manage patient's intraoperative anxiety under spinal anaesthesia. It is recommended to measure intraoperative anxiety under spinal anaesthesia with using both objective and subjective methods. RELEVANCE TO CLINICAL PRACTICE: Clinical nurses can use non-pharmacological interventions to manage intraoperative anxiety under spinal anaesthesia by comprehensive monitoring with diverse measures.

Efficacy of intravenous dexamethasone on postoperative pain after caesarean delivery under spinal anaesthesia with an intrathecal long-acting opioid: a systematic review and meta-analysis.

PURPOSE: Intravenous dexamethasone is recommended in elective caesarean delivery to decrease postoperative pain. However, the efficacy of spinal anaesthesia with an intrathecal long-acting opioid such as morphine or diamorphine for caesarean delivery has not been systematically investigated. METHODS: We searched all randomized controlled trials (RCTs) of pregnant women undergoing caesarean delivery under spinal anaesthesia with an intrathecal morphine or diamorphine via MEDLINE, CENTRAL, EMBASE, ICTRP, and ClinicalTrials.gov on May 18, 2022. Primary outcomes were time to first rescue analgesia, consumption of oral morphine equivalents, and incidence of drug-related adverse reactions. We evaluated the risk of bias for each outcome using the Risk of Bias 2. We conducted a meta-analysis using a random effects model. We evaluated the certainty of evidence with the GRADE approach. RESULTS: Five RCTs (455 patients) were included. The results of intravenous dexamethasone were as follows: time to first rescue analgesia (mean difference [MD] 0.99 h, 95% confidence interval [CI] - 0.86 to 2.84; very low certainty) and consumption of oral morphine equivalents (MD - 6.55 mg, 95% CI - 17.13 to 4.02; moderate certainty). No incidence of drug-related adverse reactions was reported (very low certainty). CONCLUSION: The evidence was very uncertain about the efficacy of intravenous dexamethasone on time to first rescue analgesia and the incidence of drug-related adverse reactions. Intravenous dexamethasone probably reduces the consumption of oral morphine equivalents. Anaesthesiologists might want to consider intravenous dexamethasone for postoperative pain after caesarean delivery under spinal anaesthesia with an intrathecal long-acting opioid.

Comparison of the Effect of Forced-air Warming and Warmed Intravenous Fluid on the Comfort and Prevention of Shivering After Spinal Anesthesia in Patients Undergoing Orthopedic Surgery.

PURPOSE: This study aimed to compare the effect of forced-air warming and warmed intravenous fluid on the comfort and prevention of shivering after spinal anesthesia in patients undergoing orthopaedic surgery. DESIGN: Randomized controlled clinical trial. METHODS: A total of 120 patients were randomly divided into three groups: forced-air warming (38°C), warmed intravenous fluid (37°C), and the control group. Patients' comfort and severity of shivering were measured and recorded five times (immediately and 15 minutes after spinal anesthesia, end of the surgery, time of entrance to the recovery room, and 15 minutes after entering the recovery room), and compared with each other. FINDINGS: There was a significant difference between the three groups in terms of comfort at all points of evaluation times (P < .001). The comfort score in the control group was significantly higher than the two intervention groups (P < .001). Moreover, the comfort score in the warmed intravenous fluid group was significantly higher than the forced-air warming group (P < .001). In addition, there was a significant difference in shivering severity between the three groups at the end of the surgery, entrance to the recovery room, and 15 minutes after surgery (P < .001). The majority of patients in the forced-air warming group (90%) had no shivering at all three times, while the warmed IV fluid and control groups was 65% and 30% respectively. CONCLUSIONS: Non-pharmacological methods such as forced-air warming and warmed intravenous fluid can provide comfort and prevent shivering in orthopaedic patients undergoing spinal anesthesia. However, the use of forced-air warming is more effective than warmed intravenous fluid in providing comfort and preventing shivering in these patients. It is recommended that these methods be used in the operating room to provide comfort and prevent shivering in these patients.

Spinal arachnoid sleeves and their possible causative role in cauda equina syndrome and transient radicular irritation syndrome.

INTRODUCTION: We have previously described arachnoid sleeves around cauda equina nerve roots, but at that time we did not determine whether injections could be performed within those sleeves. The purpose of this observational study was to establish whether the entire distal orifice of a spinal needle can be accommodated within an arachnoid sleeve. MATERIALS AND METHODS: We carefully dissected the entire dural sacs off four fresh cadavers, opened them by longitudinal incision, and immersed them in saline. Under direct vision, we penetrated the cauda equina roots nerves traveling almost vertically downward at 30 locations each with a 27- and a 25-G pencil-point needle (60 punctures total). We captured the images with a stereoscopic camera. RESULTS: The nerve root offered no noticeable resistance to needle entry. Although the arachnoid sleeves could not be identified with the naked eye, they were translucent but visible under microscopy. In 21 of 30 attempts with a 27-gauge needle, and in 20 of 30 attempts with a 25-gauge needle, the distal orifice of the spinal needle was completely within the arachnoid sleeve. CONCLUSION: It seems possible to accommodate the distal orifice of a 25- or a 27-gauge pencil-point spinal needle completely within the space of the arachnoid sleeve. An injection within this sleeve could potentially lead to a neurological syndrome, as we have previously proposed.

A systematic review of phenylephrine vs. noradrenaline for the management of hypotension associated with neuraxial anaesthesia in women undergoing caesarean section.

Phenylephrine is recommended for the management of hypotension after spinal anaesthesia in women undergoing caesarean section. Noradrenaline, an adrenergic agonist with weak ß-adrenergic activity, has been reported to have a more favourable haemodynamic profile than phenylephrine. However, there are concerns that noradrenaline may be associated with a higher risk of fetal acidosis, defined as an umbilical artery pH < 7.20. We performed a systematic review of trials comparing noradrenaline with phenylephrine, concentrating on primary outcomes of fetal acidosis and maternal hypotension. We identified 13 randomised controlled trials including 2002 patients. Heterogeneity among the studies was high, and there were too few data to calculate a pooled effect estimate. Fetal acidosis was assessed in four studies that had a low risk of bias and a low risk of confounding, that is, studies which used a prophylactic vasopressor and where women received the allocated vasopressor only. There were no significant differences between these studies. No significant differences were observed for hypotension. Two trials found a significantly lower incidence of bradycardia when using noradrenaline. Cardiac output was significantly higher after noradrenaline in two of three studies. For other secondary outcomes including nausea, vomiting and Apgar scores at 1 and 5 min, no studies found significant differences. The evidence so far is too limited to support an advantage of noradrenaline over phenylephrine. Concerns of a deleterious effect of noradrenaline on fetal blood gas status cannot currently be assuaged by the available data from randomised controlled studies.

Sciatic obturator femoral technique versus spinal anaesthesia in patients undergoing surgery for fixation of open tibial fractures using Ilizarov external fixator. A randomised trial.

BACKGROUND: Peripheral nerve block is preferable for lower extremity surgery because it sufficiently blocks pain pathways at different levels providing excellent anaesthesia at the site of surgery. We designed this study to compare the efficacy and safety of SOFT block (sciatic-obturator-femoral technique) compared with spinal anaesthesia in patients undergoing surgery for fixation of open tibial fractures using Ilizarov external fixator. METHODS: One hundred and seven patients ASA I, II scheduled for fixation of open tibial fractures using Ilizarov external fixator. The patients were randomly allocated to receive either spinal anaesthesia or SOFT block. In spinal anaesthesia group, patients received spinal anaesthesia with hyperbaric bupivacaine 0.5% (7. 5-10mg). In SOFT group, patients received SOFT block with bupivacaine 0.25%. Primary endpoint included the duration of analgesia. The secondary endpoints included patient satisfaction scores, visual analogue scores, incidence of adverse events as vomiting, systemic toxicity from local anaesthetic drug and time to first effect of the techniques. RESULTS: The duration of SOFT block and time to first analgesic dose in SOFT group was significantly longer (p < 0.001). There was no significant difference between the study groups regarding satisfaction scores, the incidence of cardiovascular collapse, seizures and paraesthesia. Pain scores were significantly lower in SOFT group at 3,6,12 h postoperative (p < 0.001). The time to the first effect was significantly longer in SOFT group (p < 0.001). CONCLUSION: SOFT is a feasible technique of local anaesthesia for control of postoperative pain with unremarkable adverse events compared with spinal anaesthesia, in patients undergoing fixation of tibial fractures using Ilizarov external fixator. TRIAL REGISTRATION: This trial was retrospectively registered at ClinicalTrials.gov. registry number: NCT03450798 on February 20, 2018.

Is Spinal Anesthesia Safer than General Anesthesia for Patients Undergoing Revision THA? Analysis of the ACS-NSQIP Database.

BACKGROUND: The incidence of revision THA continues to increase and there is a need to identify risk factors contributing to postoperative complications. Anesthesia type has been shown to be associated with complication rates in patients who undergo primary THA, but it is not clear whether the same is true among patients undergoing revision THA. QUESTIONS/PURPOSES: (1) After controlling for confounding variables, in the setting of a large-database analysis, is spinal anesthesia associated with a lower risk of death, readmission, reoperation, postoperative transfusion, thromboembolic events, surgical site infection (SSI), and re-intubation among patients undergoing revision THA? METHODS: The American College of Surgeons-National Surgical Quality Improvement (ACS-NSQIP) database was queried for patients undergoing aseptic, revision THA with either spinal or general anesthesia. Coarsened exact matching was used to match patients based on several baseline characteristics, including age, sex, body mass index, surgery type (Current Procedural Terminology code), and the modified Frailty Index score. Coarsened exact matching is a statistical method of exact matching that matches on chosen characteristics, in which continuous variables may be temporarily coarsened (such as, into discrete categorical variables) to facilitate matching. This method is an alternate to and requires less estimation than traditional propensity score matching. Then, using a model controlling for baseline patient characteristics and operative time, we performed multivariate logistic and linear regression analyses of matched cohorts to examine differences in mortality, readmission, reoperation, thromboembolic events, transfusion, SSI, and re-intubation. RESULTS: After statistical matching and controlling for baseline demographic variables, surgery type (one- or two-component revision), surgical time and modified Frailty Index we found that patients receiving general anesthesia had higher odds of mortality (OR 3.72 [95% CI 1.31 to 10.50]; p = 0.013), readmission (OR 1.49 [95% CI 1.24 to 1.80]; p < 0.001), reoperation (OR 1.40 [95% CI 1.13 to 1.73]; p = 0.002), thromboembolic events (OR 2.57 [95% CI 1.37 to 4.84]; p = 0.003), SSI (OR 1.32 [95% CI 1.01 to 1.72]; p = 0.046), postoperative transfusion (OR 1.57 [95%CI 1.39 to 1.78]; p < 0.001) and unplanned intubation or failure to wean off intubation (OR 5.95 [95% CI 1.43 to 24.72]; p = 0.014). CONCLUSIONS: In patients undergoing revision THA, spinal anesthesia is associated with a decreased risk of several complications. The current investigation suggests that, when practical (such as when long surgical times or changes to the surgical plan are not anticipated), spinal anesthesia should be considered for use during revision THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Norepinephrine prophylaxis for postspinal anesthesia hypotension in parturient undergoing cesarean section: a randomized, controlled trial.

OBJECTIVE: To investigate the efficacy and safety of prophylactic infusion of norepinephrine (NE) versus normal saline in patients undergoing cesarean section. METHODS: Patients (n = 97) were randomized to receive a bolus of NE (6 µg) immediately following spinal anesthesia with maintenance NE (0.05 µg/kg/min IV) or normal saline (n = 98). The primary endpoint was the incidence of postspinal anesthesia hypotension [systolic blood pressure (SBP) < 80% of baseline] at 1-20 min following spinal anesthesia. Secondary outcomes were the overall stability of SBP control versus baseline, inferior vena cava collapsibility index (IVC-CI), other adverse events (bradycardia, nausea, vomiting, and hypertension), and neonatal outcomes (blood gas values and Apgar scores). RESULTS: The rates of postspinal anesthesia hypotension and severe postspinal anesthesia hypotension (SBP < 60% of the baseline) were significantly lower in the NE group (17.5% vs. 62.2%, p < 0.001; 7.2% vs. 17.4%, p = 0.031). In the NE group, SBP remained more stable and closer to baseline (p < 0.001), and IVC-CI values were lower 5 min after spinal anesthesia and 5 min after fetal delivery (p = 0.045; p < 0.001, respectively). Other adverse effects and neonatal outcomes were not different between the two groups. CONCLUSION: Prophylactic NE infusion effectively lowers the incidence of postspinal anesthesia hypotension and does not increase other adverse events in patients or neonates.

Spinal anesthesia for ambulatory surgery: current controversies and concerns.

PURPOSE OF REVIEW: General anesthesia is a popular choice for ambulatory surgery. Spinal anesthesia is often avoided because of perceived delays due to time required to administer it and prolonged onset, as well as concerns of delayed offset, which may delay recovery and discharge home. However, the reports of improved outcomes in hospitalized patients undergoing total joint arthroplasty have renewed the interest in spinal anesthesia. This review article critically assesses the role of spinal anesthesia in comparison with fast-track general anesthesia for the outpatient setting. RECENT FINDINGS: The purported benefits of spinal anesthesia include avoidance of airway manipulation and the adverse effects of drugs used to provide general anesthesia, improved postoperative pain, and reduced postoperative opioid requirements. Improved postoperative outcomes after spinal anesthesia in hospitalized patients may not apply to the outpatient population that tends to be relatively healthier. Also, it is unclear if spinal anesthesia is superior to fast-track general anesthesia techniques, which includes avoidance of benzodiazepine premedication, avoidance of deep anesthesia, use of an opioid-sparing approach, and minimization of neuromuscular blocking agents with appropriate reversal of residual paralysis. SUMMARY: The benefits of spinal anesthesia in the outpatient setting remain questionable at best. Further studies should seek clarification of these goals and outcomes.

Comparison of Intermittent Intravenous Boluses of Phenylephrine and Norepinephrine to Prevent and Treat Spinal-Induced Hypotension in Cesarean Deliveries: Randomized Controlled Trial.

BACKGROUND: Phenylephrine (PE) is currently the vasopressor of choice to prevent and treat spinal-induced hypotension at cesarean delivery (CD). However, its use is often associated with reflex bradycardia. Norepinephrine (NE) has been put forward as an alternative vasopressor during CD due to its ability to treat hypotension while maintaining heart rate (HR). Recent studies have focused on the role of NE used as an infusion with favorable results compared to PE. No studies have compared equipotent bolus doses of PE and NE at CD. We hypothesized that when used in equipotent doses as an intermittent bolus regimen to prevent and treat spinal-induced hypotension, NE would result in a reduction in the incidence of bradycardia compared to PE. METHODS: This was a double-blind, randomized clinical trial of women undergoing elective CD under spinal anesthesia. Women were randomized to receive either PE 100 µg or NE 6 µg when the systolic blood pressure (SBP) was below baseline. In addition to the randomized treatment, ephedrine was given intravenously to both groups if the SBP was below baseline and the HR <60 bpm or if the SBP was <80% of baseline for 2 consecutive readings. The primary outcome was bradycardia (HR <50 bpm) in the predelivery period. Secondary outcomes included hypotension (SBP <80% of baseline), hypertension (SBP >120% of baseline), tachycardia (HR >120% of baseline), ≥2 episodes of bradycardia, nausea, vomiting, umbilical artery and vein blood gases, and Apgar scores. RESULTS: One hundred twelve patients were randomized. The incidence of bradycardia was lower in the NE group compared to the PE group (10.7% vs 37.5%; P < .001; difference [95% confidence interval {CI}], -26.8% [-41.8% to -11.7%]), implying an estimated 71% relative reduction (95% CI, 35%-88%). The distribution of the number of bradycardia episodes was also different between the 2 groups (P = .007). Further testing showed that the patients in the PE group had a higher risk of multiple bradycardia episodes (≥2 episodes) compared to the NE group (19.6% for PE versus 3.6% for NE; P = .008). The proportion of patients requiring rescue boluses of ephedrine was lower in the NE group compared to the PE group (7.2% for NE versus 21.4% for PE; P < .03; difference [95% CI], -14.3% [-27.0% to -1.6%]). No differences were observed between the 2 groups in the incidence of other secondary outcomes. CONCLUSIONS: When used as an intermittent bolus regimen to prevent and treat spinal-induced hypotension during CD, NE resulted in a significant reduction in the incidence of bradycardia as compared to an equipotent bolus regimen of PE. We conclude that the hemodynamic profile offered by NE during CD is superior to that of PE due to less fluctuations in HR and possibly cardiac output.

Comparison of Intraoperative Sedation With Dexmedetomidine Versus Propofol on Acute Postoperative Pain in Total Knee Arthroplasty Under Spinal Anesthesia: A Randomized Trial.

BACKGROUND: In patients undergoing total knee arthroplasty under spinal anesthesia, we compared the postoperative analgesic effect of intraoperative sedation with dexmedetomidine versus propofol. We hypothesized that sedation with dexmedetomidine would result in lower postoperative opioid analgesic consumption than with propofol. METHODS: Forty-eight patients were enrolled and randomly assigned to either a dexmedetomidine group (n = 24), which received a loading dose of 1 µg/kg dexmedetomidine over 10 minutes, followed by a continuous infusion of 0.1-0.5 µg·kg·hour, or a propofol group (n = 24), which received a continuous infusion of propofol via a target-controlled infusion to maintain the effect-site concentration within a range of 0.5-2.0 µg/mL. The drug infusion rate was determined according to the sedation level, targeting a modified observer's assessment of alertness/sedation score of 3 or 4. The cumulative amounts of fentanyl administered via intravenous patient-controlled analgesia were recorded at 24 and 48 hours postoperatively (primary outcome). The postoperative numerical rating scale for pain was assessed at 6, 12, 24, and 48 hours (secondary outcome). The postoperative use of additional rescue analgesic (ketoprofen) and antiemetic drugs was also compared between the 2 groups at 24 and 48 hours. RESULTS: Dexmedetomidine significantly reduced postoperative fentanyl consumption (median [interquartile range]) during 0-24 hours (45 [30-71] vs 150 [49-248] µg, P = .004; median difference = -105 µg [99.98% CI, 210-7.5]), 24-48 hours (90 [45-143] vs 188 [75-266] µg, P = .005; median difference = -98 µg [99.98% CI, 195-45]), and 0-48 hours (135 [68-195] vs 360 [146-480] µg, P = .003; median difference = -225 µg [99.98% CI, 405-7.5]). The numerical rating scale (median [interquartile range]) was lower at 6 hours (1 [0-2] vs 2 [1-3], P = .003), 12 hours (1 [1-2] vs 3 [2-3], P < .001), 24 hours (1 [1-2] vs 3 [2-3], P < .001), and 48 hours (2 [2-3] vs 3 [3-4], P < .001) after surgery in the dexmedetomidine group compared to the propofol group. No significant intergroup differences were observed in the amount of rescue analgesics and antiemetics at 24 hours (P = .155 and P = .482) and 48 hours (P = .082 and P = .153) after surgery. CONCLUSIONS: Intraoperative dexmedetomidine sedation was associated with a small but clinically important reduction in postoperative opioid use after total knee arthroplasty.

SPINAL ANAESTHESIA-INDUCED HYPOTENSION IN OBSTETRICS: PREVENTION AND THERAPY.

Regional centro-axial anaesthesia, primarily spinal block, is the preferred method of anaesthesia for elective caesarean section because it entails fewer risks for the mother and the foetus compared to general anaesthesia. The most common side effect associated with spinal block is hypotension due to sympatholysis, occurring in up to 75% of cases. Spinal block-induced sympatholysis leads to vasodilatation and consequently causes maternal hypotension, which may compromise uterine blood flow and foetal circulation, and thus cause foetal hypoxia, bradycardia and acidosis. The selection of the most efficient treatment strategy to achieve haemodynamic stability during spinal anaesthesia for caesarean section continues to be one of the main challenges in obstetric anaesthesiology. A number of measures for the prevention and treatment of spinal block-induced hypotension are used in clinical practice, such as preloading and coloading with crystalloid and/or colloid infusion, wrapping of lower limbs with compression stockings or bandages, administering an optimal dose of local anaesthetic and achieving an optimal spinal block level, left tilt positioning, and administering inotropes and vasopressors. Instead of administering vasopressors after a drop in blood pressure has already occurred, the latest algorithms recommend a prophylactic administration of vasopressor infusion. The preferred vasoconstrictor in this case is phenylephrine, which is associated with a lower incidence of foetal acidosis, and maternal nausea and vomiting compared to other vasoconstrictors.

Clonidine Effect on Pain After Cesarean Delivery: A Randomized Controlled Trial of Different Routes of Administration.

BACKGROUND: Intrathecal clonidine prolongs spinal anesthesia. We evaluated the effects of the addition of intrathecal or intravenous clonidine (75 µg) to standard cesarean delivery spinal anesthesia on postoperative pain and neonatal outcomes. METHODS: In a randomized, placebo-controlled, double-blind trial, 64 women scheduled for elective cesarean delivery under spinal anesthesia were randomly allocated and compared among 3 groups: intrathecal clonidine 75 µg, intravenous clonidine 75 µg, and placebo. The primary outcome was acute postoperative pain. A sample size of 26 individuals per group (N = 78) was planned. RESULTS: From April 2015 to April 2016, 64 women were analyzed (14 excluded). No differences in postoperative pain scores were found (Numerical Verbal Scale for pain at movement at 24 hours of postcesarean delivery: 4.53 ± 3.0 vs 4.45 ± 2.73 vs 3.93 ± 3.07 for control, intrathecal, and intravenous, respectively, P = .771). Intrathecal and intravenous clonidine led to more sedation, in comparison to the control group, during the intraoperative period (Richmond Agitation and Sedation Scale: -0.3 ± 0.47 vs -1 ± 0.53 vs -0.73 ± 0.45 for control, intrathecal, and intravenous, respectively, overall P < .001; Dunn correction: P < .001 for intrathecal versus control; P = .021 for intravenous versus control; and P = .208 for intrathecal versus intravenous). CONCLUSIONS: Intrathecal or intravenous clonidine had no effect on postoperative pain after cesarean delivery. Both intrathecal and intravenous clonidine caused more sedation.

Spinal cord injury arising in anaesthesia practice.

Spinal cord injury arising during anaesthetic practice is a rare event, but one that carries a significant burden in terms of morbidity and mortality. In this article, we will review the pathophysiology of spinal cord injury. We will then discuss injuries relating to patient position, spinal cord hypoperfusion and neuraxial techniques. The most serious causes of spinal cord injury - vertebral canal haematoma, spinal epidural abscess, meningitis and adhesive arachnoiditis - will be discussed in turn. For each condition, we draw attention to practical, evidence-based measures clinicians can undertake to reduce their incidence, or mitigate their severity. Finally, we will discuss transient neurological symptoms. Some cases of spinal cord injury during anaesthesia can be ascribed to anaesthesia itself, arising as a direct consequence of its conduct. The injury to a spinal nerve root by inaccurate and/or incautious needling during spinal anaesthesia is an obvious example. But in many cases, spinal cord injury during anaesthesia is not caused by, related to, or even associated with, the conduct of the anaesthetic. Surgical factors, whether direct (e.g. spinal nerve root damage due to incorrect pedicle screw placement) or indirect (e.g. cord ischaemia following aortic surgery) are responsible for a significant proportion of spinal cord injuries that occur concurrently with the delivery of regional or general anaesthesia.