Spinal-induced hypotension: Incidence, mechanisms, prophylaxis, and management: Summarizing 20 years of research

Prophylactic norepinephrine combined with 6% hydroxyethyl starch (130/0.4) co-load infusion for preventing postspinal anesthesia hypotension during cesarean section: a randomized, controlled, dose-finding trial

PURPOSE

Colloid and/or co-load may be more effective than crystalloid for preventing postspinal anesthesia hypotension. We tested five different prophylactic norepinephrine dosages combined with colloid co-load infusion in patients receiving cesarean section and spinal anesthesia.

METHODS

Patients were randomly allocated to receive different prophylactic norepinephrine dosages (0 [NE 0 group], 0.025 [NE 25 group], 0.05 [NE 50 group], 0.075 [NE 75 group], or 0.1 [NE 100 group] µg/kg/min) combined with 500 mL 6% hydroxyethyl starch (130/0.4) immediately following spinal anesthesia (n = 35 per group). The primary endpoint was the incidence of postspinal anesthesia hypotension (systolic blood pressure [SBP] < 80% of baseline). Secondary endpoints included severe hypotension, bradycardia, nausea or vomiting, hypertension, SBP stability control versus baseline, the 50% (effective dose, ED50) and 90% (ED90) dose effective for preventing postspinal anesthesia hypotension, Apgar scores, and umbilical cord blood gases.

RESULTS

The incidence of postspinal anesthesia hypotension was 48.6%, 31.3%, 17.1%, 14.3%, and 5.7% in the respective groups. As the prophylactic norepinephrine dosage increased, the incidence of postspinal anesthesia hypotension declined (p < 0.001), and SBP remained stable relative to baseline (median performance error [MDPE], p < 0.001; median absolute performance error [MDAPE], p = 0.001). The ED50 and ED90 values were -0.006 (95% CI -0.046-0.013) and 0.081 (95% CI 0.063-0.119) µg/kg/min. Other endpoints were comparable across the groups.

CONCLUSION

An initial prophylactic norepinephrine dosage of 0.05 µg/kg/min combined with 500 mL 6% hydroxyethyl starch (130/0.4) co-load infusion was optimal for preventing postspinal anesthesia hypotension during cesarean section.

TRIAL REGISTRATION

NCT05133817, registration date: 12 Nov, 2021.

Changes in the corrected carotid flow time can predict spinal anesthesia-induced hypotension in patients undergoing cesarean delivery: an observational study

PURPOSE

Spinal anesthesia is a standard technique for cesarean delivery; however, it possesses a risk of hypotension. We hypothesised that the changes in the corrected flow time induced by the Trendelenburg position could predict the incidence of hypotension after spinal anesthesia for cesarean delivery.

METHODS

Patients undergoing elective cesarean delivery under spinal anesthesia were enrolled. Before anesthesia induction, corrected flow time was measured in the supine and Trendelenburg positions (FTc-1 and FTc-2, respectively). Additionally, a percent change in corrected flow time induced by the Trendelenburg position was defined as ΔFTc. The primary endpoint was to investigate the ability of ΔFTc to predict the incidence of spinal anesthesia-induced hypotension until delivery. The receiver operating characteristics curves to assess the ability of FTc-1, FTc-2, and ΔFTc to predict the incidence of hypotension were generated.

RESULTS

Finally, 40 patients were included, and of those, 26 (65%) developed spinal anesthesia-induced hypotension. The areas under the curve for FTc-1, FTc-2, and ΔFTc were 0.591 (95% CI: 0.424 to 0.743) (P = 0.380), 0.742 (95% CI: 0.579 to 0.867) (P = 0.004), and 0.882 (95% CI: 0.740 to 0.962) (P < 0.001) respectively, indicating ΔFTc as the best predictor among these three parameters. The best threshold for ΔFTc was 6.4% (sensitivity: 80.8% (95% CI: 53.8 to 96.2), specificity: 85.7% (95% CI: 42.9 to 100.0)).

CONCLUSIONS

This study demonstrated that changes in the corrected carotid flow time induced by the Trendelenburg position could serve as a good predictor of spinal anesthesia-induced hypotension for cesarean delivery.

Norepinephrine prevents hypotension in older patients under spinal anesthesia with intravenous propofol sedation: a randomized controlled trial

Reducing hypotension is crucial as hypotension is the most common side effect of spinal anesthesia, and in older patients with various comorbidities, it can lead to fatality. We hypothesized that continuous infusion of norepinephrine could effectively prevent hypotension in older patients undergoing hip surgery under spinal anesthesia with propofol sedation. The study randomly assigned patients aged ≥ 70 years to either a control (Group C, n = 35) or a norepinephrine group (Group N, n = 35). After spinal anesthesia, continuous infusion of propofol and normal saline or norepinephrine was initiated. The number of hypotensive episodes, the primary outcome, as well as other intraoperative hemodynamic events and postoperative complications were compared. In total, 67 patients were included in the final analysis. The number of hypotensive episodes was significantly higher in Group C than in Group N (p < 0.001). Furthermore, Group C required a greater amount of fluid to maintain normovolemia (p = 0.008) and showed less urine output (p = 0.019). However, there was no difference in postoperative complications between the two groups. Continuous intravenous infusion of prophylactic norepinephrine prevented hypotensive episodes, reduced the requirement of fluid, and increased the urine output in older patients undergoing unilateral hip surgery under spinal anesthesia with propofol sedation.Clinical trial registration number: KCT0005046 ( https://cris.nih.go.kr ). IRB number: 2020-0533 (Institutional Review Board of Asan Medical Center, approval date: 13/APR/2020).

Comparison of crystalloid and colloid co-load combined with norepinephrine prophylaxis on post-spinal anesthesia hypotension during cesarean delivery: a randomized sequential allocation dose-finding study

Background

Fluid loading is an essential component of treatment for reducing the incidence of post-spinal anesthesia hypotension and is necessary to maintain intravascular volume, perfuse tissues, and control spinal anesthesia hypotension after sympathetic blockade. We performed a randomized sequential allocation dose-finding study to compare the effects of 10 mL/kg crystalloid and 6% hydroxyethyl starch (130/0.4) co-load on the ED90 of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery.

Methods

Eighty patients were randomly allocated to receive either a 10 mL/kg crystalloid (Crystalloid Group, n = 40) or 6% hydroxyethyl starch (130/0.4) (Colloid Group, n = 40) co-load combined with prophylactic norepinephrine infusion during spinal anesthesia for cesarean delivery. The first patient received an initial prophylactic norepinephrine infusion rate of 0.025 μg/kg/min. Subsequent patients received a 0.005 μg/kg/min gradient dose of prophylactic norepinephrine. This dose was administered as a gradient based on its effectiveness for preventing post-spinal anesthesia hypotension (defined as SBP < 80% of baseline value) and determined by the up-and-down sequential allocation methodology. The primary study outcome was the ED90 of prophylactic norepinephrine infusion. Secondary outcomes included the incidence of post-spinal anesthesia hypotension, bradycardia, hypertension, Apgar scores, and umbilical artery blood gas values were also measured.

Results

The ED90 values of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery were 0.063 μg (95% CI: 0.050 to 0.064) and 0.062 μg (95% CI: 0.045 to 0.064) using isotonic regression analysis, and 0.068 μg (95% CI: 0.056 to 0.353) and 0.060 μg (95% CI: 0.050 to 3.590) using probit regression analysis in the Crystalloid Group and Colloid Group, respectively. The secondary outcomes were comparable between the two groups.

Conclusion

The administration of a 10 mL/kg 6% hydroxyethyl starch (130/0.4) does not provide additional benefits compared to crystalloid co-load in reducing the ED90 of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery.

Association between intraoperative hypotension and postoperative nausea and vomiting: a retrospective analysis of 247 thyroidectomy cases

BACKGROUND

Postoperative nausea and vomiting (PONV) are major complications after general anesthesia. Although various pathways are involved in triggering PONV, hypotension plays an important role. We hypothesized that intraoperative hypotension during general anesthesia might be responsible for the incidence of PONV.

METHODS

We retrospectively investigated patients who underwent thyroidectomy. The initial blood pressure measured before induction of anesthesia was used as the baseline value. The systolic blood pressure measured during the operation from the start to the end of anesthesia was extracted from anesthetic records. The time integral value when the measured systolic blood pressure fell below the baseline value was calculated as area under the curve (AUC) of s100%.

RESULTS

There were 247 eligible cases. Eighty-eight patients (35.6%) had PONV. There was no difference in patient background between the patients with or without PONV. Univariate analysis showed that the total intravenous anesthesia (TIVA) (p=0.02), smoking history (p=0.02), and AUC-s100% (p=0.006) were significantly associated with PONV. Multiple logistic regression analysis revealed that TIVA (OR: 0.54, 95% CI: 0.29...0.99), smoking history (OR: 0.60, 95% CI: 0.37...0.96), and AUC-s100% (OR: 1.006, 95% CI: 1.0...1.01) were significantly associated with PONV.

CONCLUSION

Intraoperative hypotension evaluated by AUC-s100% was related to PONV in thyroidectomy.

Comparison of Dural Puncture Epidural, Epidural and Combined Spinal-Epidural Anesthesia for Cesarean Delivery: A Randomized Controlled Trial

Purpose

Catheter-based techniques such as combined spinal-epidural (CSE) anesthesia which are sometimes indicated for obstetric anesthesia have a complex mechanism of action. The application of the dural puncture epidural (DPE) anesthesia for cesarean section (CS) has not been well investigated. The present study compared the relatively novel DPE technique with epidural (EA) and CSE anesthesia.

Patients and Methods

We randomly assigned 150 parturients who underwent elective CS to receive DPE, EA or CSE anesthesia. The primary outcome was the onset of sensory anesthesia to the T5 dermatome assessed using the Cox proportional hazards model. Secondary outcomes included median time to sensory block, quality of block, patient and surgeon satisfaction, APGAR scores and other side effects.

Results

For DPE anesthesia versus EA anesthesia, the onset of anesthesia was faster (hazard ratio 2.47 [95% CI 1.56 to 3.90], adjusted P < 0.001) and the median time to surgical level was shorter (16 [IQR 14-18] min versus 19 [15.5-21] min, adjusted P < 0.001); the incidence of intraoperative pain was lower (7/48 versus 17/47, adjusted P = 0.046) and the median patient satisfaction score was higher (9 [IQR 9-10] versus 8 [8-9.5], adjusted P = 0.004). In the CSE group, the onset of anesthesia was faster than in the other two but the incidence of hypotension was higher (P < 0.001) and the phenylephrine requirement was greater (P < 0.001).

Conclusion

DPE anesthesia had a faster onset and better quality of block than EA anesthesia and provided less influence to maternal hemodynamic parameters than CSE anesthesia for CS. These results suggest that the dural puncture plays a significant role in enhancing the effectiveness of epidural top-ups during CSE anesthesia and indicates enlightenment that contributes to the satisfaction of anesthetic effect in DPE technique labor analgesia transferred to CS.

Comparing the Effect of Phenylephrine Bolus and Phenylephrine Infusion for Maintaining Arterial Blood Pressure During Cesarean Delivery Under Spinal Anesthesia: A Randomized Prospective Study

INTRODUCTION

 Maternal hypotension is a common complication of spinal anesthesia in cesarean section and requires immediate intervention. Phenylephrine is most commonly used as a vasopressor agent for the treatment of hypotension due to subarachnoid block. Our aim was to compare the bolus dose of 50 µg of phenylephrine with a fixed infusion at 50 µg.min-1 of phenylephrine for maintaining arterial blood pressure during cesarean delivery.

MATERIALS AND METHOD

 This was a prospective, randomized comparative study. One hundred normotensive pregnant females aged 18-35 years, body mass index 18-29kg.m2, American Society of Anesthesiologists (ASA) physical status classification II scheduled to undergo cesarean section (elective/emergency) under spinal anesthesia were randomly divided into two groups of 50 each. Group PB received a bolus dose of phenylephrine 50 µg after they developed hypotension i.e., a decrease in systolic blood pressure (SBP) ≥ 20% from the baseline. Similarly, patients in Group PI were administered prophylactic infusion using a syringe pump of phenylephrine 50 µg.min-1, started just after the administration of subarachnoid block. The phenylephrine infusion was continued either till the delivery of the baby or when SBP rises >20% above the baseline. Parameters like blood pressure, heart rate, and peripheral oxygen saturation were recorded. After the delivery of the baby, the neonatal APGAR score was assessed at one minute and five minutes.

RESULTS

Demographic data were comparable in terms of demographic profile, duration of surgery, and ASA physical status classification between the groups. The heart rate was higher in Group PB compared to Group PI throughout the monitoring period (P<0.001). The fall in mean blood pressure was more in Group PB compared to Group PI till 18 minutes of surgery and was statistically significant (P<0.05). After 18 minutes of surgery, mean blood pressure stabilized and was comparable between the groups. Other variables like APGAR score at one minute and five minutes were comparable between the groups. Bradycardia and hypertension were more common in Group PI whereas hypotension, nausea, and vomiting were more common in group PB.

CONCLUSION

We concluded that during cesarean section under spinal anesthesia, phenylephrine infusion provides better hemodynamic stability and APGAR score during the perioperative period.

Prophylactic Norepinephrine and Phenylephrine Boluses to Prevent Postspinal Anesthesia Hypotension During Cesarean Section: A Randomized Sequential Allocation Dose-Finding Study

Background

Norepinephrine and phenylephrine are widely used for obstetric anesthesia. Our central objective was to determine the ED (effective dose) 90 and potency ratio of prophylactic norepinephrine and phenylephrine boluses for preventing postspinal anesthesia hypotension during cesarean section.

Methods

Patients scheduled for elective cesarean section (n = 80) were randomly allocated to receive prophylactic norepinephrine (NE) or phenylephrine (PE) boluses immediately after induction of spinal anesthesia. An initial dose of NE (3 μg) and PE (37.5 μg) was given to the first patient, and an up-and-down sequential allocation method was used to determine the next dose level according to the responses (the effectiveness for preventing postspinal anesthesia hypotension [defined as SBP < 80% of baseline value]). Primary outcomes were ED90 and the potency ratio of prophylactic norepinephrine and phenylephrine boluses. Secondary outcomes were the incidence of postspinal anesthesia hypotension, severe postspinal anesthesia hypotension, nausea, vomiting, bradycardia, hypertension, umbilical artery blood gas values, and Apgar scores.

Results

The ED90 values for prophylactic norepinephrine and phenylephrine boluses were 8.0 μg (95% CI 7.1-11.0 μg) and 90.9 μg (95% CI 82.0-123.9 μg), respectively. The estimated relative potency ratio was 11.4:1. The incidence of bradycardia was lower in the NE group (2.5% vs 20%, P = 0.034). Other outcomes were comparable between the two groups.

Conclusion

An 8-μg prophylactic bolus of norepinephrine and a 90-μg prophylactic bolus of phenylephrine can effectively prevent postspinal anesthesia hypotension in patients during cesarean section.

Intraoperative phenylephrine infusion to reduce perioperative shivering in lower segment caesarean section: A randomised controlled study

BACKGROUND

Shivering is described as an involuntary, repetitive activity of the skeletal muscles that can have deleterious effects on anaesthetized patients. This study aimed to evaluate the effectiveness of phenylephrine infusion in preventing perioperative shivering in patients undergoing lower segment cesarean section under spinal anesthesia and to observe the change in the patient's core temperature between the study and control groups.

METHODS

A total of 118 patients scheduled for elective lower segment cesarean section under spinal anesthesia were recruited for this prospective, double-blind, randomized controlled study. The patients were randomized into 2 groups with 59 patients per group. The phenylephrine Group received phenylephrine infusion at a rate of 0.5 mcg/kg/minutes, while the Control Group received normal saline at an equivalent rate. Systolic and diastolic blood pressure, heart rate, core temperature, and the presence and intensity of shivering were recorded before induction and every 15 minutes intraoperatively and postoperatively.

RESULTS

The incidence of intraoperative shivering was significantly lower in the Phenylephrine Group compared to control group (29.1% vs 47.5% respectively; P = .044). Postoperatively, the Phenylephrine Group also had a lower incidence of shivering (34.5% vs 42.4%), but the difference was not statistically significant (P value = 0.391). There were no significant differences in the intensity of shivering between the 2 groups perioperatively, as well as in the systolic and diastolic blood pressure and core temperature. The phenylephrine Group showed a significantly lower heart rate at 15, 30, and 45 minutes after spinal block (P value = .005, .000, and .008, respectively), and at 0 and 30 minutes (P value = .004 and .020 respectively) in the recovery room. There were no significant differences in perioperative adverse events such as hypotension, hypertension, and bradycardia.

CONCLUSION

Phenylephrine infusion reduces the incidence of perioperative shivering in lower segment cesarean sections under spinal anesthesia.

Preanesthetic ultrasonography assessment of inferior vena cava diameter in the supine position, left lateral tilt position, and with the left uterine displacement maneuver in full-term pregnant women: A randomized cross-over design study

Preanesthetic ultrasonography assessment of inferior vena cava diameter (IVCD) in the supine position (SP), left lateral tilt position (LLT), and with the left uterine displacement maneuver (LUD) in full-term pregnant women: a randomized cross-over design study.

AIM

We pre-anesthetically measured IVCD using ultrasonography in the SP, LLT, and the LUD in full-term pregnant women, using a cross-over design, to evaluate the effectiveness of LLT and LUD on increasing IVCD, and the presence of inter-individual differences among patients in the effect of posture on IVCD.

METHODS

Twenty-two parturients scheduled for elective cesarean section under spinal anesthesia were recruited. All patients were sequentially placed in the SP, LLT, and with LUD before spinal anesthesia induction. Indices of IVCD, measured by subxiphoid ultrasonography, including maximum IVCD (IVCDmax), minimum IVCD (IVCDmin), and collapsibility index (CI) were recorded in each of the postures. Mean or median values of all measurements were compared among the postures.

RESULTS

The mean values of IVCDmax observed with both LLT and LUD were significantly larger than those in the SP, respectively (SP vs. LLT: p < 0.05, SP vs. LUD: p < 0.01), although there were no significant differences between IVCDmax with LLT and LUD. There were no significant differences in IVCDmin and CI between any of the postures. IVCDmax was highest with LUD in 11 patients (55%), in the LLT in seven patients (35%) and in the SP in two patients (10%).

CONCLUSIONS

LLT and LUD might be equally effective in enlarging the narrowed IVCD as compared to SP. However, both LLT and LUD might not necessarily be appropriate treatments to relieve IVC compression in some cases.

Comparison of the effects of hydroxyethyl starch and succinylated gelatin infusion on the perfusion index in elective caesarean sections under spinal anaesthesia

Aim: This study is to compare the alterations of three different replacement fluids on Perfusion Index, Pleth Variability Index (PI, PVI) and hemodynamic data in cases planned to experience caesarean surgery under spinal anaesthesia. Material and Method: 94 ASAII class patients aged 18–40 that were planned to experience caesarean surgery were included in the study. The patients were divided into three groups according to the fluid replacement to be applied. Patients in Group H received 10 ml/kg of hydroxyethyl starch (HES) up to a maximum of 500 ml over 20 minutes. Patients in Group G got 10 ml/kg of modified liquid gelatin(GEL) up to a maximum of 500 ml over 20 minutes. Patients in Group I got 20 ml/kg of isotonic sodium chloride (0.9% NaCl) over 20 minutes. Routine monitoring and perfusion index, pleth variability index were recorded baseline and at the first, third and tenth min after spinal anaesthesia for all participants Results: A significant increase in the PI value over time was observed in Groups G and I (p=0.001*). According to the PVI results, the amount of decrease in Group G was statistically less than in the other two groups (p=0.015*). Conclusion: In conclusion, 0.9% NaCl and gelatine were more effective on PI in caesarean section under spinal anesthesia. Isotonic has a positive effect on both PI and PVI. We detected that PI increased compared to baseline values, and believe that this increase may a positive effect on tissue circulation in the patient.

Spinal hypotension in obstetrics: Context-sensitive prevention and management

Spinal hypotension during caesarean section remains a common complication, with important attendant maternal and fetal adverse outcomes. Research elucidating the mechanisms of spinal hypotension has led to the development and refinement of effective management strategies, with a particular emphasis on prophylactic vasopressor administration. This has proved effective in well-resourced settings, with maternal comfort and the elimination of nausea now considered the primary aim of treatment. In resource-limited settings, sophisticated strategies are not feasible due to insufficient equipment, staff, and expertise. Therefore, in these areas spinal hypotension remains an important cause of maternal and fetal morbidity and mortality. Translational, context-sensitive research in resource-limited settings has shown promise in implementing pragmatic strategies based on research from resource-rich environments. We review the current best practice for the prevention and treatment of spinal hypotension, with a special emphasis on effective strategies in resource-limited settings. We further suggest a research agenda to address the knowledge gap in specific contexts.

Distribution of cesarean delivery by Robson classification and predictors of postspinal anesthesia hypotension in Windhoek referral hospitals: A cross-sectional study

Background

There are concerns that high cesarean section (CS) rates are driven by nonmedical indications and unmitigated maternal hypotension following spinal anesthesia (SA) has materno fetal effects.

Aims

Our objective was to investigate CS rates using Robson classification, identify patient groups for focused intervention as well as assess the incidence and predictors of maternal hypotension following SA for cesarean delivery.

Subjects and Methods

A cross sectional design was employed over 3 months (February-April, 2019). Data about total deliveries (vaginal and operative) were obtained from the hospital medical records. For parturients who had CS, variables which covered maternal characteristics, conduct of anesthesia, and the index pregnancy according to Robson classification system were entered into a proforma designed for the study.

Results

The total deliveries were 3031, of which 556 were CSs, giving a CS rate of 18.3%. Twenty one nonconsenting parturients were excluded, so 535 responded. Robson groups 5, 10, and 1 combined contributed 75% [401/535] to the overall CS. Two or more previous CS, 29.7% [159/535], was the main indication for performing CS, followed by maternal request 12.9% [69/535]. The incidence of maternal hypotension was 62.6% (293/468); the independent predictors were elective CS and having comorbidities.

Conclusion

We found a low CS rate and Robson groups 5, 10, and 1 were the major contributors - previous CS (≥2) and maternal request were the predominant indications for performing CS. The independent predictors of SA induced hypotension were presence of comorbidities and elective CS.

Performance of the Hypotension Prediction Index With Noninvasive Arterial Pressure Waveforms in Awake Cesarean Delivery Patients Under Spinal Anesthesia

BACKGROUND

Arterial hypotension is common after spinal anesthesia (SA) for cesarean delivery (CD), and to date, there is no definitive method to predict it. The hypotension prediction index (HPI) is an algorithm that uses the arterial waveform to predict early phases of intraoperative hypotension. The aims of this study were to assess the diagnostic ability of HPI working with arterial waveforms detected by ClearSight system in predicting impending hypotension in awake patients, and the agreement of pressure values recorded by ClearSight with conventional noninvasive blood pressure (NIBP) monitoring in patients undergoing CD under SA.

METHODS

In this retrospective analysis of pregnant patients scheduled for elective CD under SA, continuous hemodynamic data measured with the ClearSight monitor until delivery were downloaded from an Edwards Lifesciences HemoSphere platform and analyzed. Receiver operating characteristic (ROC) curves were constructed to evaluate the performance of HPI algorithm working on the ClearSight pressure waveform in predicting hypotensive events, defined as mean arterial pressure (MAP) <65 mm Hg for >1 minute. The sensitivity, specificity, positive predictive value, and negative predictive value were computed at the optimal cutpoint, selected as the value that minimizes the difference between sensitivity and specificity. ClearSight MAP values were compared to NIBP MAP values by linear regression and Bland-Altman analysis corrected for repeated measurements.

RESULTS

Fifty patients undergoing CD were included in the analysis. Hypotension occurred in 23 patients (48%). Among patients experiencing hypotension, the HPI disclosed 71 alerts. The HPI predicted hypotensive events with a sensitivity of 83% (95% confidence interval [CI], 69-97) and specificity of 83% (95% CI, 70-95) at 3 minutes before the event (area under the curve [AUC] 0.913 [95% CI, 0.837-0.99]); with a sensitivity of 97% (95% CI, 92-100) and specificity of 97% (95% CI, 92-100) at 2 minutes before the event (AUC 0.995 [95% CI, 0.979-1.0]); and with a sensitivity of 100% (95% CI, 100-100) and specificity 100% (95% CI, 100-100) 1 minute before the event (AUC 1.0 [95% CI, 1.0-1.0]). A total of 2280 paired NIBP MAP and ClearSight MAP values were assessed. The mean of the differences between the ClearSight and NIBP assessed using Bland-Altman analysis (±standard deviation [SD]; 95% limits of agreement with respective 95% CI) was -0.97 mm Hg (±4.8; -10.5 [-10.8 to -10.1] to 8.5 [8.1-8.8]).

CONCLUSIONS

HPI provides an accurate real time and continuous prediction of impending intraoperative hypotension before its occurrence in awake patients under SA. We found acceptable agreement between ClearSight MAP and NIBP MAP.

Granisetron or ondansentron to prevent hypotension after spinal anesthesia for elective cesarean delivery: A randomized placebo-controlled trial

STUDY OBJECTIVE

This study aimed to compare the effects of high doses of ondansetron and granisetron before spinal anesthesia on hemodynamic parameters in patients undergoing elective cesarean section.

DESIGN

A double-blinded randomized placebo-controlled trial.

SETTING

Operating room.

PATIENTS

A total of 120 parturients with term pregnancy undergoing elective cesarean section with combined spinal-epidural anesthesia were included.

INTERVENTIONS

Three groups (n = 40 for each group) were formed by randomization. Five minutes before the anesthesia procedure, Group I received 8 mg intravenous (IV) ondansetron diluted in 10 ml normal saline, Group II received IV 3 mg granisetron diluted in 10 ml normal saline, and Group III received IV 10 ml normal saline.

MEASUREMENTS

Following intrathecal drug administration, intraoperative hemodynamic changes were recorded every 2 min for 20 min and then every 5 min until the end of the operation.

MAIN RESULTS

Twenty patients (50%) in Group I, 12 patients (30%) in Group II, and 29 patients (72.5%) in Group III had hypotension requiring treatment with IV ephedrine (P = 0.001). The ephedrine requirement in Group III was significantly higher than in Groups I (P = 0.033) and II (P < 0.001). Also, the ephedrine requirement in Group II was lower than in Group I, but the difference was not statistically significant (P = 0.055). The mean arterial pressure for the three groups differed in the 10th, 18th, and 60th minutes. The number of patients with nausea or vomiting was lower in Groups I and II than in Group III (P < 0.001). At 5 min, the Apgar scores were higher than 8 for all neonates. Postoperative scores for the visual analogue scale were similar for all groups.

CONCLUSIONS

It was concluded that prophylactic IV administration of 3 mg of granisetron or 8 mg of ondansetron before spinal anesthesia results in a significantly lower ephedrine requirement compared to placebo.

Predictability of preoperative carotid artery-corrected flow time for hypotension after spinal anaesthesia in patients undergoing caesarean section: A prospective observational study

BACKGROUND

Spinal anaesthesia-induced hypotension is frequently reported in patients undergoing caesarean section. Mechanistically, sympathetic blockade reduces the systemic vascular resistance and the left ventricular preload, causing hypotension, which is augmented by aortocaval compression. The corrected blood flow time (FTc) is affected by the preload and is inversely related to the afterload.

OBJECTIVE

We hypothesised that the preanaesthetic carotid artery FTc could predict hypotension after induction in patients undergoing a caesarean section with spinal anaesthesia.

DESIGN

A prospective observational study.

SETTING

A tertiary referral centre in South Korea from September 2018 to November 2019.

PARTICIPANTS

Thirty-eight parturients scheduled for elective caesarean section under spinal anaesthesia.

INTERVENTIONS

Using carotid ultrasonography, FTc was measured twice prior to inducing spinal anaesthesia. FTc was calculated using both Bazett's (B) and Wodey's (W) formulae. Hypotension was defined as an SBP decrease to less than 80 mmHg, or less than 75% of baseline, or if symptoms consistent with hypotension occurred from the time of injection of the spinal anaesthetic until delivery.

MAIN OUTCOME MEASURES

The primary endpoint was to determine the predictive value of preanaesthetic FTc for postspinal hypotension during caesarean delivery.

RESULTS

Among the 35 patients who completed this study, hypotension occurred in 21 (60%). The areas under the receiver-operating characteristic curves for FTc (B) and FTc (W) were 0.905 [95% confidence interval (CI), 0.757 to 0.978, P < 0.001] and 0.922 (95% CI, 0.779 to 0.985, P < 0.001), respectively. The optimal cut-off values for predicting hypotension were 346.4 and 326.9 ms, respectively. The grey zone for FTc (B) and FTc (W) included 40 and 14% of the patients, respectively.

CONCLUSION

Preanaesthetic carotid artery FTc was a reliable indicator of postspinal hypotension in parturients. Considering the grey zone, Wodey's formula is better than Bazett's formula.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03631329.

Maternal Oxygen Supplementation Compared With Room Air for Intrauterine Resuscitation: A Systematic Review and Meta-analysis

IMPORTANCE

Supplemental oxygen is commonly administered to pregnant women at the time of delivery to prevent fetal hypoxia and acidemia. There is mixed evidence on the utility of this practice.

OBJECTIVE

To compare the association of peripartum maternal oxygen administration with room air on umbilical artery (UA) gas measures and neonatal outcomes.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials were searched from February 18 to April 3, 2020. Search terms included labor or obstetric delivery and oxygen therapy and fetal blood or blood gas or acid-base imbalance.

STUDY SELECTION

Studies were included if they were randomized clinical trials comparing oxygen with room air at the time of scheduled cesarean delivery or labor in patients with singleton, nonanomalous pregnancies. Studies that did not collect paired umbilical cord gas samples or did not report either UA pH or UA Pao2 results were excluded.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by 2 independent reviewers. The analysis was stratified by the presence or absence of labor at the time of randomization. Data were pooled using random-effects models.

MAIN OUTCOMES AND MEASURES

The primary outcome for this review was UA pH. Secondary outcomes included UA pH less than 7.2, UA Pao2, UA base excess, 1- and 5-minute Apgar scores, and neonatal intensive care unit admission.

RESULTS

The meta-analysis included 16 randomized clinical trials (n = 1078 oxygen group and n = 974 room air group). There was significant heterogeneity among the studies (I2 = 49.88%; P = .03). Overall, oxygen administration was associated with no significant difference in UA pH (weighted mean difference, 0.00; 95% CI, -0.01 to 0.01). Oxygen use was associated with an increase in UA Pao2 (weighted mean difference, 2.57 mm Hg; 95% CI, 0.80-4.34 mm Hg) but no significant difference in UA base excess, UA pH less than 7.2, Apgar scores, or neonatal intensive care unit admissions. Umbilical artery pH values remained similar between groups after accounting for the risk of bias, type of oxygen delivery device, and fraction of inspired oxygen. After stratifying by the presence or absence of labor, oxygen administration in women undergoing scheduled cesarean delivery was associated with increased UA Pao2 (weighted mean difference, 2.12 mm Hg; 95% CI, 0.09-4.15 mm Hg) and a reduction in the incidence of UA pH less than 7.2 (relative risk, 0.63; 95% CI, 0.43-0.90), but these changes were not noted among those in labor (Pao2: weighted mean difference, 3.60 mm Hg; 95% CI, -0.30 to 7.49 mm Hg; UA pH<7.2: relative risk, 1.34; 95% CI, 0.58-3.11).

CONCLUSIONS AND RELEVANCE

This systematic review and meta-analysis suggests that studies to date showed no association between maternal oxygen and a clinically relevant improvement in UA pH or other neonatal outcomes.

Effect of prophylactic combination of glycopyrrolate, ondansetron, and ephedrine upon hypotension during obstetric spinal anaesthesia–A randomised controlled trial

Background and Aims:

Various pharmacological and non-pharmacological strategies have been employed to minimise hypotension during obstetric spinal anaesthesia. We compared a prophylactic combination of glycopyrrolate, ondansetron, and ephedrine in terms of total vasopressor consumption, with standard treatment in this randomised controlled trial.

Methods:

One hundred patients undergoing elective caeserean sections were randomly divided into two groups of 50 each, the study group received prophylactic ondansetron and glycopyrrolate boluses followed by an infusion of ephedrine, while the control group received ephedrine boluses as required. The total ephedrine consumption (primary objective), incidence and degree of hypotension, heart rate variations, and neonatal APGAR scores (secondary objectives) were analysed.

Results:

The median ephedrine requirement was lesser in the study group compared to the control group [13.2 mg (10--15.75) vs. 27.7 mg (12--24)], with a P value of 0.02. Fewer participants experienced hypotension in the study group before baby delivery compared to the control group (12 vs. 36, P = 0.004). Heart rate was higher in the study group. No significant differences were observed in neonatal APGAR scores and incidence of adverse events.

Conclusion:

A combination of glycopyrrolate, ondansetron, and ephedrine might offer better haemodynamic stability and reduce vasopressor consumption in obstetric patients undergoing spinal anaesthesia as opposed to standard treatment.

What obstetricians should know about obstetric anesthesia during the COVID-19 pandemic

The COVID-19 pandemic has prompted obstetric anesthesiologists to reconsider the ways in which basic anesthesia care is provided on the Labor and Delivery Unit. Suggested modifications include an added emphasis on avoiding general anesthesia, a strong encouragement to infected individuals to opt for early neuraxial analgesia, and the prevention of emergent cesarean delivery, whenever possible. Through team efforts, adopting these measures can have real effects on reducing the transmission of the viral illness and maintaining patient and caregiver safety in the labor room.

Ultrasound-Guided Unilateral Transversus Abdominis Plane Combined with Rectus Sheath Block versus Subarachnoid Anesthesia in Patients Undergoing Peritoneal Dialysis Catheter Surgery: A Randomized Prospective Controlled Trial

Background

Peritoneal dialysis catheter placement can be performed under general anesthesia, local anesthesia or subarachnoid anesthesia (SA). Recently, studies have reported the successful placement of peritoneal dialysis catheters using a transversus abdominis plane (TAP) block and rectus sheath (RS) block. This study compared the TAP + RS block with SA for patients undergoing peritoneal dialysis catheter placement.

Methods

Sixty patients were randomly divided into two groups, with 30 receiving unilateral ultrasound-guided TAP + RS block anesthesia and 30 receiving SA. The demographic characteristics, anesthesia efficacy, indicators related to anesthesia or operation, hemodynamic index, postoperative pain numeric rating score (NRS), postoperative recovery indicators, complications related to anesthesia or surgery, and dosage of sedative or analgesic medication were analyzed.

Results

Anesthesia operation time was significantly shorter in the TAP + RS block group than in the SA group (P<0.001), while there was no significant difference in success rates (TAP + RS 93.33% [95% confidence interval, 95% CI, 83.9–102.8%] vs SA 100.00% [95% CI, 100–100%], P=0.472). Two patients in the TAP + RS group needed extra analgesia, although the dermatome pinprick sensation test gave negative results for all patients. Patients who received the TAP + RS block expressed significantly less pain on movement or at rest at 4 h and 8 h postoperative. Fewer patients needed rescue analgesia with tramadol in the postoperative period in the TAP + RS block group than in the SA group (P<0.05). The intraoperative MAP was more stable (P<0.05) in the TAP + RS group compared to the SA group.

Conclusion

The TAP + RS block is a safe, effective method for use as the principal anesthesia technique in PD catheter placement. Compared to SA, it has the advantages of less influence on hemodynamics and a better postoperative analgesic effect.

A randomised dose-response study of prophylactic Methoxamine infusion for preventing spinal-induced hypotension during Cesarean delivery

BACKGROUND

α-receptor agonists have been reported to be safe and effective for treating or preventing spinal-induced hypotension during cesarean delivery. As a pure α₁ adrenergic agonist, methoxamine has potential advantages of reducing myocardial oxygen consumption and protecting the heart in obstetric patients compared to phenylephrine. The aim of this study was to determine the optimal prophylactic methoxamine infusion dose that would be effective for preventing spinal-induced hypotension in 50% (ED₅₀) and 95% (ED₉₅) of parturients.

METHODS

Eighty parturients with a singleton pregnancy scheduled for elective cesarean delivery were randomly allocated to receive prophylactic methoxamine infusion at one of four different fixed-rates: 1 μg/kg/min (group M1), 2 μg/kg/min (group M2), 3 μg/kg/min (group M3), or 4 μg/kg/min (group M4). An adequate response was defined as absence of hypotension (maternal SBP < 80% of baseline or SBP < 90 mmHg). The values for ED₅₀ and ED₉₅ of prophylactic methoxamine infusion were determined by probit regression model. The outcomes of maternal hemodynamics and fetal status were compared among the groups.

RESULTS

The calculated ED₅₀ and ED₉₅ (95% confidence interval) of prophylactic methoxamine infusion dose were 2.178 (95% CI 1.564 to 2.680) μg/kg/min and 4.821 (95% CI 3.951 to 7.017) μg/kg/min, respectively. The incidence of hypotension decreased with increasing methoxamine infusion dose (15/20, 11/20, 7/20 and 2/20 in group M1, M2, M3 and M4 respectively, P <  0.001). 1-min Apgar scores and umbilical arterial PaO2 were lower but umbilical arterial PaCO2 was higher in Group M1. No difference was found in the other incidence of adverse effects and neonatal outcomes among groups.

CONCLUSIONS

Under the conditions of this study, when prophylactic methoxamine infusion was given at a fixed-rate based on body weight for preventing spinal-induced hypotension in obstetric patients, the values for ED₅₀ and ED₉₅ were 2.178 μg/kg/min and 4.821 μg/kg/min respectively.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), registry number of clinical trial: ChiCTR-1,800,018,988 , date of registration: October 20, 2018.

Evaluating the Relationship between the Pleth Variability Index and Hypotension and Assessing the Fluid Response in Geriatric Hip Fracture under Spinal Anaesthesia: An Observational Study

OBJECTIVE

We aimed to test the efficacy of the pre-operative Pleth variability index (PVI) in evaluating hypotension that developed after spinal anaesthesia in patients who were spontaneously breathing, pre-operatively hypovolemic, and were at an advanced age.

METHODS

This observational study included 94 patients aged >65 years with hip fracture. Demographic data, pre-operative heart rate, non-invasive arterial pressures, PVI values, and haemogram values were continuously measured following spinal anaesthesia. The measurements with and without hypotension were distinguished and their data were compared.

RESULTS

The mean age of the patients was 77.4±8.2 years. In total, 56.4% of the patients developed hypotension after spinal anaesthesia, and hypotension was higher in women (p=0.037). Low pre-operative diastolic arterial pressures values were associated with the development of hypotension (p=0.037). The relationship between PVI and post-spinal hypotension was negative but significant (r=-0.239; p<0.05). Depending on the volume loss, an increase in the PVI (p<0.001) and its subsequent significant decrease after treatment in patients with hypotension (p<0.001) was observed. The correlation between noninvasively measured haemoglobin values and the values obtained from arterial blood gas samples was significant (p<0.001).

CONCLUSION

This study showed that post-spinal hypotension may be associated with increased as well as decreased PVI values. However, these values cannot be clinically used for predicting pre-operative hypotension in hypovolemic patients.

The Impact of Spinal Anesthesia and Use of Oxytocin on Fluid Absorption in Patients Undergoing Operative Hysteroscopy: Results from a Prospective Controlled Study

Objective

The aim of this study was to determine if combining intravenous oxytocin infusion and spinal anesthesia will reduce the amount of glycine absorption in patients undergoing operative hysteroscopy.

Patients and Methods

A prospective controlled study was conducted in premenopausal patients who had hysteroscopic surgery including endometrial resection, endometrial polypectomy, myomectomy resection and uterine septal resection. The effect of combined spinal anesthetic with oxytocin infusion on fluid deficit was studied.

Results

A total of 88 patients were studied. Sixty-two cases were done under general anesthesia (control group) and 26 cases were performed with spinal anesthesia and the use of oxytocin infusion (study group). There was a statistically significant less mean fluid deficit in the study group than control group in the endometrial polypectomy patients (220±36 mL vs 392±178 mL, respectively, P value 0.010, 95% C.I.: 163–276) and the myomectomy patients (308±66 mL vs 564±371 mL, respectively, P value 0.003, 95% C.I.: 239–378). In the endometrial resections, there was also a statistically significant less mean fluid deficit in the study than the control group (P value ˂ 0.001). Regarding septal resection, there was no statistically significant difference in the mean fluid deficit between the two groups (P value 0.833).

Conclusion

Spinal anesthesia combined with intravenous oxytocin infusion in operative hysteroscopy results in a statistically significant reduction in the glycine fluid deficit than the general anesthesia. We also recommend studying the effects of this combination in operative hysteroscopy using bipolar devices with isotonic solutions.

Hemodynamic changes after spinal anesthesia in preeclamptic patients undergoing cesarean section at a tertiary referral center in Ethiopia: a prospective cohort study

Background

Spinal anesthesia-induced maternal hypotension is the most frequent complication associated with maternal morbidity and mortality during Cesarean section. The aim of this study was to compare the incidence and magnitude of hemodynamic changes in preeclamptic and non-preeclamptic parturients undergone Cesarean section under spinal anesthesia.

Method

A prospective cohort study was conducted from 01 February to 28 May 2019 in preeclamptic and non-preeclamptic parturients. We hypothesized preeclamptic parturients are at high risk of spinal anesthesia induced hypotension than non preeclamptics. A total of 122 ASA II and ASA III parturients were recruited consecutively and assigned to two groups (81non-preeclamptics, and 41 preeclamptics). Parturients with cardiac disease, twin pregnancy, chronic hypertension, gestational hypertension, superimposed hypertension, renal disease, diabetes mellitus, coagulopathy (platelet count < 80 × 10⁹/L), active labor, eclampsia, abruptio placentae, placenta praevia, any adjuvant added with local anesthetics were excluded. The data analysis was done using SPSS version 22 statistical software. Student t test, MannWhitney U test and Fisher exact test were used to compare the data. All P values < 0.05 were considered statistically significant.

Result

The incidence of spinal anesthesia-induced hypotension was higher in non-preeclamptic parturients than preeclamptic parturients (55.6% vs. 34.1%, respectively) and the degree of blood pressure drop was significantly greater in the non-preeclamptic parturients compared to those with preeclampsia; As well intraoperative fluid consumption was significantly greater in the non-preeclamptics parturients compared to those with preeclamptics.

Conclusion

The incidence and magnitude of spinal anesthesia-induced hypotension in parturients undergone Cesarean section were less in preeclamptic parturients than in non-preeclamptic parturients.. Based on the data from this study we recommended spinal anesthesia for preeclamptic patients, unless there is a contra indication based on preeclampsia.

Possible Impact of Spinal Anesthesia and Phenylephrine on Sublingual Microcirculation of Cesarean Delivery Patients

Background

This study was a proof of concept of a novel means to evaluate microcirculatory changes during spinal anesthesia for cesarean delivery. It sought to examine the distributive circulatory effects of spinal anesthesia and evaluate the impact of phenylephrine administration on the microcirculation of these women.

Methods

After Research Ethics Board approval, healthy, non-laboring pregnant women with singleton, term pregnancies scheduled for elective cesarean delivery were recruited. Participants were randomly assigned to receive either phenylephrine infusion or phenylephrine bolus. Spinal anesthesia was standardized. A sidestream dark-field (SDF) MicroScan^® video microscope was applied to the sublingual mucosa to obtain microcirculation videos in five different visual fields. Videos were made before and after spinal anesthesia. The resultant videos were analyzed randomly and blindly. The mean microvascular flow index (MFI) values were compared before and after spinal anesthesia. The difference in MFI following spinal anesthesia was compared between phenylephrine infusion and bolus groups.

Results

Thirty-two patients were recruited for the study; 22 patients had complete video sets for analysis. Baseline characteristics were similar between the two groups, including preoperative hemodynamics. There were no significant differences between pre- and post-spinal MFI. The post-spinal MFI within the infusion group (mean ± standard deviation: 2.74 ± 0.21) was not significantly different from the bolus group (2.56 ± 0.42, P = 0.22).

Conclusion

Despite theoretical physiological implications of spinal anesthesia and phenylephrine on the microcirculation, significant alteration of the MFI was not observed between pre- and post-spinal anesthesia (within group). Additionally, despite an eight-fold larger phenylephrine dose for continuous infusion prophylaxis used in this group of women, this did not result in a significant alteration of the microcirculation compared to those who received phenylephrine treatment for hypotension (between groups).

Effect of lower leg compression during cesarean section on post-spinal hypotension and neonatal hemodynamic parameters: nonrandomized controlled clinical trial

Objectives

This study aimed to determine the effect of lower leg compression during cesarean section (CS) on post-spinal hypotension (PSH) and neonatal hemodynamic parameters.

Methods

This study is a nonrandomized controlled clinical trial conducted in the cesarean delivery unit of the National Medical institute, Damanhour, Egypt. The sample included 120 parturients (60 intervention and 60 control). The researchers developed three tools for data collection: sociodemographic data and reproductive history interview schedule, electronic monitoring of maternal hemodynamic parameters, and neonatal hemodynamic assessment sheet. All parturients received ordinary pre-operative care. For the intervention group, a long elastic stocking (ordinary pressure 20–30 mmHg, 1 mmHg = 0.133 kPa) was applied on both legs during cesarean section. The control group received the same care without the elastic stocking.

Results

Systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure were significantly higher in the intervention group throughout the entire operation period except in the last 5–15 min. Heart rate was significantly lower in the intervention group. Only 13.3% of the intervention group took ephedrine compared with 45% of the control group. Apgar score was higher among neonates of intervention group compared with the control group at 1 min. Neonatal acidosis was significantly higher in the control group than in the contral group.

Conclusion

Lower leg compression technique can effectively reduce PSH and neonatal acidosis.

Spinal anesthesia-induced hypotension is caused by a decrease in stroke volume in elderly patients

Background

Hypotension is common during spinal anesthesia (SA) and is caused by a decrease in systemic vascular resistance (SVR) and/or cardiac output (CO). The effect of the dose of bupivacaine administered intrathecally on the changes in CO in elderly patients is largely unknown. This study investigated the hemodynamic effect of SA in elderly patients by studying the effect of two different dosages of intrathecal bupivacaine.

Methods

This prospective cohort study included 64 patients aged >65 years scheduled for procedures under SA; the patients received either 15 mg bupivacaine (the medium dose [MD] group) or 10 mg bupivacaine and 5 μg sufentanil (the low dose [LD] group). Blood pressure and CO were monitored throughout the procedure using Nexfin™, a noninvasive continuous monitoring device using a finger cuff.

Results

Thirty-three patients received MD and 31 received LD and there was no mean difference in baseline hemodynamics between the groups. On an average, the CO decreased 11.6% in the MD group and 10.0 % in the LD group. There was no significant change in SVR. Incidence of a clinically relevant decrease in stroke volume (SV) (>15% from baseline) was 67% in the MD and 45% in the LD groups (P<0.05).

Conclusion

CO and blood pressure decreased significantly after the onset of SA in elderly patients. This is mainly caused by a decrease in SV and not by a decrease in SVR. There was no difference in CO and blood pressure change between dosages of 10 or 15 mg bupivacaine.

Can the inferior vena cava collapsibility index be useful in predicting hypotension during spinal anaesthesia in a spontaneously breathing patient? A mini fluid challenge

The study was performed at the Department of Orthopaedics and Traumatology of the Kauno Klinikos Hospital of Lithuanian University of Health Sciences.

BACKGROUND

Intravascular fluids are empirically administered to prevent hypotension induced by spinal anaesthesia. Ultrasound measurements of the inferior vena cava (IVC) and the IVC collapsibility index (IVC-CI) is a non-invasive method to evaluate the intravascular volume status. The aim of the study was to identify the prognostic value of the IVC collapsibility index in spontaneously breathing patients to predict severe intraoperative hypotension.

MATERIALS AND METHODS

Sixty patients undergoing elective knee arthroplasty under spinal anaesthesia were included in the prospective study. The diameters of IVCex, IVCin, and IVC-CI were measured before and 15 min after spinal anaesthesia when administration of 500 ml of normal saline using infusion pump was finished. The haemodynamic parameters (heart rate, systolic, diastolic, and mean blood pressures, breathing rate) were collected.

RESULTS

Severe arterial hypotension was noticed in 18.3% of the patients. No statistically significant differences were detected between changes in IVCex, IVCin, and IVC-CI comparing hypotensive and non-hypotensive patients at the baseline and after the interventions (p > 0.005). According to receiver operating characteristic (ROC) analysis, IVC-CI is not effective in the prediction of severe hypotension during spinal anaesthesia in spontaneously breathing patients: the area under the ROC curve for IVC-CI was <0.7, p > 0.05.

CONCLUSIONS

IVC-CI is not an effective predictor of severe hypotension after induction of spinal anaesthesia followed by normal saline administration in spontaneously breathing patients undergoing elective knee arthroplasty. More trials, including different patient subgroups, will be needed.

Crystalloid coloading vs. colloid coloading in elective Caesarean section: postspinal hypotension and vasopressor consumption, a prospective, observational clinical trial

BACKGROUND

Maternal hypotension is a common side effect of spinal anaesthesia for Caesarean section. The combination of colloid coloading and vasopressors was considered our standard for its prevention and treatment. As the safety of hydroxyethyl starch is under debate, we replaced colloid with crystalloid coloading.

OBJECTIVE

We hypothesize that the mean blood pressure drop is greater when coloading with crystalloids.

DESIGN

Prospective, observational clinical trial.

SETTING

Two-centre study conducted in Berlin, Germany.

PATIENTS

Parturients scheduled for a Caesarean section were screened for eligibility.

INTERVENTION

The study protocol and patient monitoring were based on the standard operating procedure for Caesarean section in both centres. The data from the crystalloid group were prospectively collected between November 2014 and July 2015.

MAIN OUTCOME MEASURES

The primary endpoint was the median drop in mean blood pressure after induction of spinal anaesthesia. Secondary endpoints were incidence of hypotension (drop > 20% of baseline systolic pressure /drop < 100 mmHg), vasopressor and additional fluid requirements (mL), incidence of bradycardia (heart rate < 60 beats per minute), blood loss, Apgar score, and umbilical artery pH. In case of hypotension, patients received phenylephrine or cafedrine/theodrenaline according to their heart rate. A p < 0.05 was considered significant.

RESULTS

345 prospectively enrolled patients (n = 193 crystalloid group vs. n = 152 colloid group) were analysed. The median drop in mean blood pressure was greater in the crystalloid group [34 mmHg (25; 42 mmHg) vs. 21 mmHg (13; 29 mmHg), p < 0.001]. Incidences of hypotension [93.3% vs. 83.6%, p: 0.004] and bradycardia [19.7% vs. 9.9%, p: 0.012] were also significantly greater in the crystalloid group. Vasopressor requirements, blood loss and neonatal outcome were not different between the groups.

CONCLUSIONS

Crystalloid coloading was associated with a greater drop in mean blood pressure and a higher incidence of hypotension when compared with colloid coloading. Neonatal outcome was, however, unaffected by the type of fluid.

TRIAL REGISTRATION

DRKS00006783 ( http://www.drks.de ).

Study Comparing Phenylephrine Bolus and Infusion for Maternal Hypotension and Neonatal Outcome during Cesarean Section under Spinal Anesthesia

Background

Phenylephrine(PE) bolus and infusion have been compared for post spinal hypotension and neonatal effects during cesarean section(CS) under spinal anesthesia(SA).

Aim

The primary aim of this study was to compare bolus doses of 50μg of PE with a fixed infusion rate of 50 μg/min of the same drug given prophylactically. The secondary aim was to study the neonatal outcome and side effects with the two regimes.

Settings and Design

This prospective,randomized,comparative study was conducted in the department of Anesthesia in a tertiary care teaching hospital.

Materials and Methods

This study was conducted on 100 normotensive women undergoing CS under SA. The patients were randomized into two groups of 50 each. Group A received bolus of 50 μg PE after the systolic BP(SBP) fell by 20% from the baseline and Group B received a prophylactic infusion of 50 μg/min PE. The changes in heart rate (HR), BP and side effects were compared till delivery. The neonatal APGAR scores were compared at 1 and 5 minutes and an umbilical artery sample was sent for blood gas analysis.

Statistical Analysis

Categorical variables were shown in number and percentage. Normally distributed continuous variables were presented as mean ± SD and compared using unpaired t-test. Non normally distributed continuous variables were displayed as median and were compared using Mann-Whitney test. A P value of <0.05 was considered significant.

Results

In group A, the HR was higher than in group B throughout the monitoring period. (P < 0.001). In group A, SBP trend showed a fall of more than 20% from the base line in 44 patients. The mean fall in SBP was -28.06 ± 5.3 mmHg% in Group A while in group B the mean fall in SBP was only -0.44 ± 4.3mmHg%. Nausea and vomiting was less in group B. There was no difference in APGAR or neonatal acidosis on ABG.

Conclusion

There was a tighter control of BP in the infusion group vs. the bolus group while the neonatal outcome was similar in both the groups.