Weight-based oxytocin infusion for preventing uterine atony during caesarean delivery in non-labouring patients: A dose-response study.

Postpartum haemorrhage remains a significant cause of maternal morbidity and mortality with the commonest reason being uterine atony. For prevention of uterine atony during caesarean delivery, oxytocin is advocated as a first line drug. There is however no published data regarding utility of a weight-based oxytocin infusion. The present study evaluated dose-response relationship for oxytocin infusion when used as weight-based regimen. A total of 55 non-labouring patients without risk factors for uterine atony and scheduled for caesarean delivery under spinal anaesthesia were enrolled. Randomization was done to receive oxytocin infusion in a dose of 0.1, 0.15, 0.2, 0.25 or 0.3 IU kg-1  h-1 (n = 11 each), initiated at the time of cord clamping and continued until the end of surgery. Successful outcome was defined as attaining an adequate uterine response at 4 min of initiation of infusion and maintained till end of surgery. Oxytocin associated hypotension, tachycardia, ST-T changes, nausea/vomiting, flushing and chest pain were also observed. A significant linear trend for adequate intraoperative uterine tone was seen with increasing dose of weight-based oxytocin infusion (P < 0.001). The effective dose in 90% population (ED90) was 0.29 IU kg-1  h-1 (95% CI = 0.25-0.42). Amongst the oxytocin associated side effects, a significant linear trend was seen between increasing dose of oxytocin infusion and hypotension as well as nausea/vomiting (p = 0.016 and 0.023 respectively). Thus, oxytocin infusion during caesarean delivery may be used as per the patient's body weight.

Use of Pearson and Spearman correlation testing in Indian anesthesia journals: An audit.

Background and Aims: Correct usage and interpretation of biostatistical tests is imperative. Aim of the present article was to evaluate the use of "correlation test" for biostatistical analysis in two leading Indian journals of anesthesia and sensitize the readers regarding its correct usage. Material and Methods: A prospective analysis was done for all original articles using the correlation test (Pearson or Spearman) that were published in "Indian Journal of Anaesthesia" (IJA) or "Journal of Anaesthesiology and Clinical Pharmacology" (JOACP) in the years 2019 and 2020. Results: Amongst all included original studies, correlation test were used in 6% (JOACP) and 6.5% (IJA) respectively (averaged for the years 2019 and 2020). Correlation test was usedinappropriately) for evaluating an aim of prediction/agreement/comparison, rather than association, in 25% and 10% instances each (JOACP and IJA). In both JOACP and IJA, there were high rates of using and interpreting results without citing 95% confidence intervals (CIs) of correlation coefficient (88% and 90%, respectively), P value for significance of the association (50% and 90%, respectively), or coefficient of discrimination (88% and 70%, respectively). In majority of the instances, test to ascertain presence of mandatory prerequisites such as normal distribution of data could not be found (62% and 90%, respectively). Conclusion: The complete potential of correlation test in exploring research questions is probably underappreciated. Further, even when used, its application and interpretation are prone to errors. We hope that the present analysis and narrative is a well-timed appropriate step in bridging the gaps in existing knowledge regarding use of correlation test in national anesthesia literature.

Suppression of perioperative stress response in elective abdominal surgery: A randomized comparison between dexmedetomidine and epidural block.

Background and Aims: Stress response after surgery induces local and systemic inflammation which may be detrimental if it goes unchecked. Blockade of afferent neurons or inhibition of hypothalamic function may mitigate the stress response. Material and Methods: A total of 50 consenting adult ASA I/II patients undergoing elective abdominal surgery were randomized to receive either dexmedetomidine (Group D) or epidural bupivacaine (Group E) in addition to balanced general anesthesia. Laparoscopic surgery, contraindications to epidural administration, history of psychiatric disorders, obesity (BMI >30 kg/m2), on beta blockers or continuous steroid therapy for >5 days over last 1 year, and known case of endocrine abnormalities or malignancy were excluded. Serum cortisol, blood glucose, and blood urea were estimated. Hemodynamic parameters, total dose of dexmedetomidine, bupivacaine, emergence characteristics, and analgesic consumption over 24 h postoperatively were recorded. Statistical comparisons were done using Student's t-test, repeated measure analysis of variance followed by Dunnett's test, generalized linear model and Chi-square/Fisher's exact test. A P value <0.05 was considered significant. Results: Serum cortisol levels were significantly lower in group E than group D 24 h after surgery (P = 0.029). Intraoperative and postoperative glucose level was lower in group E compared with group D. Time to request of first rescue analgesic was longer in group E than group D (P = 0.040). There was no significant difference between the number of doses of paracetamol required in the postoperative period (P = 0.198). Conclusion: Epidural bupivacaine was more effective than intravenous dexmedetomidine for suppression of neuroendocrine and metabolic response to surgery. Dexmedetomidine provided better hemodynamic stability at the time of noxious stimuli and postoperatively.

Efficacy of fixed-dose phenylephrine bolus for treating post-spinal hypotension: Comparison between pre-eclamptics and normotensives.

Background and Aims: Pre-eclamptic parturients may have an exaggerated response to vasopressors. This study compares the efficacy of a 50 µg fixed bolus of phenylephrine for treatment of post-spinal hypotension in pre-eclamptic versus normotensive parturients. Material and Methods: After written informed consent and ethics committee approval, 30 normotensive and 30 pre-eclamptic parturients between 18 and 40 years with singleton term pregnancy about to undergo cesarean section (CS) under spinal anesthesia were included. Post-spinal hypotension was treated with a 50 µg fixed bolus of phenylephrine. The cumulative dose of phenylephrine, the number of boluses, and the median dose required to treat the first hypotensive episode, total number of hypotensive episodes, maternal side effects, neonatal appearance, pulse, grimace, activity, and respiration (APGAR) scores, and umbilical arterial cord blood pH were noted. Statistical analysis was done using Student's t-test, Mann-Whitney U-test, Chi-square test/Fisher's exact test as appropriate. A P <0.05 was considered significant. Results: The cumulative dose and number of boluses of phenylephrine required to treat post-spinal hypotension were comparable. The median dose required to treat the first episode of post-spinal hypotension was also similar (p = 0.792). The time to develop the first hypotensive episode was significantly earlier for group N (p = 0.002). The efficacy of a single fixed bolus of 50 µg phenylephrine was similar in both groups (p = 1.000). Neonatal median APGAR scores at 1 min after birth were significantly higher for group N (p = 0.016). Conclusion: A fixed-dose bolus of 50 µg phenylephrine is safe and effective in treating post-spinal hypotension in pre-eclampsia. The efficacy of phenylephrine is comparable in pre-eclamptic and normotensive parturients.

Effective Dose of Prophylactic Oxytocin Infusion During Cesarean Delivery in 90% Population of Nonlaboring Patients With Preeclampsia Receiving Magnesium Sulfate Therapy and Normotensives: An Up-Down Sequential Allocation Dose-Response Study.

BACKGROUND: Oxytocin administration during cesarean delivery is the first-line therapy for the prevention of uterine atony. Patients with preeclampsia may receive magnesium sulfate, a drug with known tocolytic effects, for seizure prophylaxis. However, no study has evaluated the minimum effective dose of oxytocin during cesarean delivery in women with preeclampsia. METHODS: This study compared the effective dose in 90% population (ED90) of oxytocin infusion for achieving satisfactory uterine tone during cesarean delivery in nonlaboring patients with preeclampsia who were receiving magnesium sulfate treatment with a control group of normotensives who were not receiving magnesium sulfate. This prospective dual-arm dose-finding study was based on a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h, on clamping of the umbilical cord, in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician at 4 minutes after initiation of oxytocin infusion. The dose of oxytocin infusion for subsequent patients was decided according to the response exhibited by the previous patient in the group; it was increased by 2 IU/h after unsatisfactory response or decreased by 2 IU/h or maintained at the same level after satisfactory response, in a ratio of 1:9. Oxytocin-associated side effects were also evaluated. Dose-response data for the groups were evaluated using a log-logistic function and ED90 estimates were derived from fitted equations using the delta method. RESULTS: The ED90 of oxytocin was significantly greater for the preeclampsia group (n = 27) than for the normotensive group (n = 40) (24.9 IU/h [95% confidence interval {CI}, 22.4-27.5] and 13.9 IU/h [95% CI, 12.4-15.5], respectively); the difference in dose requirement was 10.9 IU/h (95% CI, 7.9-14.0; P < .001). The number of patients with oxytocin-related hypotension, defined as a decrease in systolic blood pressure >20% from baseline or to <90 mm Hg, was significantly greater in the preeclampsia group (92.6% vs 62.5%; P = .030), while other side effects such as ST-T depression, nausea/vomiting, headache, and flushing, were not significantly different. There was no significant difference in the need for additional uterotonic or uterine massage, estimated blood loss, and need for re-exploration for uncontrolled bleeding. CONCLUSIONS: Patients with preeclampsia receiving preoperative magnesium therapy need a greater intraoperative dose of oxytocin to achieve satisfactory contraction of the uterus after fetal delivery, as compared to normotensives.

Intraabdominal pressure and its relation with organ dysfunction in patients scheduled for elective cesarean section: Effect of supine vs left lateral tilt position.

INTRODUCTION: Intraabdominal pressure (IAP) is related to clinical outcome of patients. It is measured as intravesical pressure through a Foley catheter in the supine position. During pregnancy, there are data showing elevated IAP and also a suggestion that it may be a false increase due to pressure on the urinary bladder by the gravid uterus in the supine position. Additionally, it is not known whether the elevated IAP during pregnancy is merely a physiological change or is associated with impairment of organ functions. We thus aimed to establish a normal value of IAP in supine (IAPsupine ) as well as 10° left lateral (IAPlateral-tilt ) positions, and their association with organ functions as well as certain maternal risk characteristics. MATERIAL AND METHODS: This prospective cross-sectional cohort study included 100 consenting parturients with term gestation posted for elective cesarean section under single-shot subarachnoid block. IAP was measured via an indwelling Foley catheter with a transducer connected to it, as per the recommended technique. Organ dysfunction was defined as Sequential Organ Failure Assessment (SOFA) subscore ≥1 for the particular system. TRIAL REGISTRATION: ctri.gov.in (CTRI/2017/11/010527). RESULTS: The IAPsupine was significantly higher than IAPlateral-tilt (13.8 ± 2.4 vs 12 ± 2.3 mm Hg) (P < .001). The incidence of intraabdominal hypertension as per conventional definition, that is, IAP ≥12 mm Hg, was also higher in the supine position (77% vs 55%) (P < .001). None of the patients had dysfunction of the cardiovascular, renal or central nervous system. The incidence of respiratory, hepatic and hematologic dysfunction was 2%, 15% and 32%, respectively. Receiver operating characteristic analysis showed insignificant association of IAPsupine and IAPlateral-tilt with various organ dysfunctions (P > .05). There was a significant correlation of intraabdominal hypertension when considering IAPsupine or IAPlateral-tilt , with obesity (P = .004 and .000, respectively), as well as preeclampsia (P = .006 and .000, respectively). CONCLUSIONS: In nonlaboring patients undergoing elective cesarean section, IAP is significantly higher in the supine vs 10° left lateral position. In neither position is IAP significantly associated with organ dysfunction. Thus, the usual recommendation of a supine position for measuring IAP to diagnose intraabdominal hypertension, formulated consequent to its pathological effects on organ functions, may not be applicable to pregnant patients and needs urgent validation studies.

Acute Kidney Injury in Severe Preeclamptic Patients Admitted to Intensive Care Unit: Epidemiology and Role of Serum Neutrophil Gelatinase-associated Lipocalcin.

BACKGROUND: Patients with preeclampsia admitted to the intensive care unit (ICU) may have risk factors for acute kidney injury (AKI). Although the use of neutrophil gelatinase-associated lipocalcin (NGAL) to predict AKI is previously validated, we could locate only scanty data regarding the epidemiology of AKI and role of NGAL in preeclamptic patients admitted to ICU. METHODS: Patients with preeclampsia admitted to our ICU were included. The incidence and severity of AKI during the entire ICU stay were assessed using kidney disease improving global outcomes criteria, while the a priori risk factors and serum NGAL were also evaluated. RESULTS: A total of 52 preeclamptic patients admitted to ICU were included, among whom the majority had eclampsia (75%). AKI developed in 25 (48.1%) patients with stages 1, 2, and 3 in 56, 36, and 8%, respectively. The incidence of sepsis (16 vs 0%), shock (40 vs 7.4%), and anemia (84 vs 59.3%) was significantly greater in patients with AKI (p < 0.05). ICU mortality (28 vs 3.7%), duration of ICU, and hospital stay were significantly higher in patients who developed AKI (p < 0.05). There was no association of serum NGAL [274 (240-335) ng/mL] with AKI or the mortality (p = 0.725, 0.861); there was, however, a significant discriminatory value for eclampsia [p = 0.019; area under curve = 0.736 (95% confidence interval: 0.569-0.904)]. CONCLUSIONS: Although AKI is common among patients with preeclampsia admitted to ICU, serum NGAL does not predict its occurrence. HOW TO CITE THIS ARTICLE: Tyagi A, Yadav P, Salhotra R, Das S, Singh PK, Garg D. Acute Kidney Injury in Severe Preeclamptic Patients Admitted to Intensive Care Unit: Epidemiology and Role of Serum Neutrophil Gelatinase-associated Lipocalcin. Indian J Crit Care Med 2021;25(9):1013-1019.

Intraabdominal pressure in non-laboring preeclamptic vs normotensive patients undergoing cesarean section: A prospective observational study.

INTRODUCTION: It is hypothesized that increased intraabdominal pressure (IAP) may be a cause of preeclampsia. There is, however, a paucity of clinical data regarding IAP in preeclamptics. We evaluated and compared the IAP and its effects on organ functions, in normotensive and preeclamptic patients. MATERIAL AND METHODS: Previously healthy non-laboring patients with a singleton pregnancy scheduled for elective cesarean section under subarachnoid block were enrolled (preeclamptic and normotensive; n = 29 each). IAP was measured using an indwelling Foley catheter, and compared in both cohorts at four predefined time points: just before subarachnoid block, immediately after the onset of sensory block to T6 dermatomal level, just after surgery, and 2 hours later. In addition, the presence of organ dysfunction for respiratory, cardiovascular, renal, hepatic, hematopoietic and central nervous systems were evaluated for association with IAP. RESULTS: Although age, body mass index, gravidity, parity, serum bilirubin, serum creatinine, PaO2 /FiO2 ratio and Glasgow coma score of the preeclamptic and normotensive patients were similar, the mean blood pressure was significantly higher (P < 0.001), the period of gestation less (P = 0.003) and the platelet count lower (P = 0.020) in the former. The IAP was significantly higher in the preeclamptic group at all four time points: respectively, 15.1 (1.0) vs 14.2 (0.9) mm Hg (P = 0.002); 14.9 (0.9) vs 14.1 (1.0) mm Hg (P = 0.002), 10.4 (1.0) vs 9.5 (1.3) mm Hg (P = 0.008) and 10.2 (0.8) vs 9.2 (1.2) mm Hg (P = 0.001). There was no correlation between the IAP and various organ dysfunctions. CONCLUSIONS: Preeclampsia is associated with a significantly higher IAP in patients undergoing a cesarean section. The clinical relevance of this finding needs further investigation.

Critically Ill Obstetric Patients: Much more than Meets the Eye.

How to cite this article: Tyagi A, Luthra A, Garg D. Critically Ill Obstetric Patients: Much more than Meets the Eye. Indian J Crit Care Med 2019;23(10):493.

Effect of Segmental Thoracic Epidural Block on Pancreatitisinduced Organ Dysfunction: A Preliminary Study.

BACKGROUND: This preliminary randomized controlled study evaluated effect of thoracic epidural block (TEB) on progression of acute pancreatitis induced organ dysfunction/failure. MATERIALS AND METHODS: Patients with predicted severe acute pancreatitis, without contraindication to TEB were randomized to receive (group TE) or not receive a TEB (group NTE) (n = 16 each). For group TE, TEB was performed at T8-9 or T9-10 vertebral level, with infusion of ropivacaine (0.2%) along with fentanyl 2 µg/mL; in group NTE, intravenous morphine was used instead, both interventions titrated to NRS of <4. SOFA score was assessed daily till discharge from ICU, and aggregate SOFA calculated by summing worst scores for each of organ system during ICU stay as primary outcome measure. Other surrogate measures of patient outcome were recorded as secondary objectives. RESULTS: Aggregate SOFA score was statistically similar between both groups (group NTE: 3 [2 - 4]; group TE: 5 [2 - 6]) (P = 0.379); but there was trend of improvement in SOFA score in group TE versus a worsening in group NTE. Duration of hospital stay, and number of patients requiring mechanical ventilation were statistically similar; mortality was insignificantly lesser for group TE (12.5% versus 6.6%; p = 1.000). Fall in serum procalcitonin was significantly greater for group TE. CONCLUSION: Thoracic epidural was associated with insignificant clinical trend towards better organ functions and lesser mortality; along with significantly greater fall in serum procalcitonin. These are encouraging results that could guide future use of thoracic epidural in acute pancreatitis for its non-analgesic benefits. HOW TO CITE THIS ARTICLE: Tyagi A, Gupta YR et al. Effect of Segmental Thoracic Epidural Block on Pancreatitis Induced Organ Dysfunction: A Preliminary Study. Indian J of Crit Care Med 2019;23(2):89-94.

Low tidal volume ventilation strategy and organ functions in patients with pre-existing systemic inflammatory response.

BACKGROUND AND AIMS: Ventilation can induce increase in inflammatory mediators that may contribute to systemic organ dysfunction. Ventilation-induced organ dysfunction is likely to be accentuated if there is a pre-existing systemic inflammatory response. MATERIAL AND METHODS: Adult patients suffering from intestinal perforation peritonitis-induced systemic inflammatory response syndrome and scheduled for emergency laparotomy were randomized to receive intraoperative ventilation with 10 ml.kg-1 tidal volume (Group H) versus lower tidal volume of 6 ml.kg-1 along with positive end-expiratory pressure (PEEP) of 10 cmH2O (Group L), (n = 45 each). The primary outcome was postoperative organ dysfunction evaluated using the aggregate Sepsis-related Organ Failure Assessment (SOFA) score. The secondary outcomes were, inflammatory mediators viz. interleukin-6, tumor necrosis factor-α, procalcitonin, and C-reactive protein, assessed prior to (basal) and 1 h after initiation of mechanical ventilation, and 18 h postoperatively. RESULTS: The aggregate SOFA score (3[1-3] vs. 1[1-3]); and that on the first postoperative day (2[1-3] vs. 1[0-3]) were higher for group L as compared to group H (P < 0.05). All inflammatory mediators were statistically similar between both groups at all time intervals (P > 0.05). CONCLUSIONS: Mechanical ventilation with low tidal volume of 6 ml/kg-1 along with PEEP of 10 cmH2O is associated with significantly worse postoperative organ functions as compared to high tidal volume of 10 ml.kg-1 in patients of perforation peritonitis-induced systemic inflammation undergoing emergency laparotomy.

Role of Intra-abdominal Pressure in Early Acute Kidney Injury: A Prospective Cohort Study in Critically Ill Obstetric Patients.

AIMS: This prospective cohort study evaluated intra-abdominal pressure (IAP) and its role in causing acute kidney injury (AKI) in critically ill obstetric patients and utility of urinary neutrophil gelatinase-associated lipocalin (NGAL) to predict AKI. METHODS: A total of 50 eligible obstetric patients admitted to our Intensive Care Unit were enrolled and daily IAP measured using indwelling Foley catheter. Early AKI was diagnosed as per the KDIGO criteria and urine assessed for NGAL using ELISA. RESULTS: AKI was seen in 54% and intra-abdominal hypertension (IAH) in 21% patients. In patients with and without AKI, there was statistically similar IAP on day 1 (P = 0.542) and day 2 (P = 0.907) as well as incidence of IAH (19% vs. 23%) (P = 0.766). Area under receiver operating characteristic curve (AUC) for IAP to predict early AKI was 0.499 (95% confidence interval [CI]: 0.325-0.673) (P = 0.992). Urinary NGAL concentration was significantly greater in patients with early AKI compared to those without (P = 0.006); AUC for urinary NGAL to detect early AKI was 0.734 (95% CI: 0.583-0.884) (P = 0.006) and optimal cutoff was 53.7 ng/ml. CONCLUSIONS: IAH and AKI are common in critically ill obstetric patients. While IAP does not correlate with early AKI, NGAL is useful to predict AKI.

Intraoperative low tidal volume ventilation strategy has no benefits during laparoscopic cholecystectomy.

BACKGROUND AND AIMS: Benefits of intraoperative low tidal volume ventilation during laparoscopic surgery are not conclusively proven, even though its advantages were seen in other situations with intraoperative respiratory compromise such as one-lung ventilation. The present study compared the efficacy of intraoperative low tidal volume ventilatory strategy (6 ml/kg along with positive end-expiratory pressure [PEEP] of 10 cmH2O) versus one with higher tidal volume (10 ml/kg with no PEEP) on various clinical parameters and plasma levels of interleukin (IL)-6 in patients undergoing laparoscopic cholecystectomy. MATERIAL AND METHODS: A total of 58 adult patients with American Society of Anesthesiologists physical status I or II, undergoing laparoscopic cholecystectomy were randomized to receive the low or higher tidal volume strategy as above (n = 29 each). The primary outcome measure was postoperative PaO2. Systemic levels of IL-6 along with clinical indices of intraoperative gas exchange, pulmonary mechanics, and hemodynamic consequences were measured as secondary outcome measures. RESULTS: There was no statistically significant difference in oxygenation; intraoperative dynamic compliance, peak airway pressures, or hemodynamic parameters, or the IL-6 levels between the two groups (P > 0.05). Low tidal volume strategy was associated with significantly higher mean airway pressure, lower airway resistance, greater respiratory rates, and albeit clinically similar, higher PaCO2and lower pH (P < 0.05). CONCLUSION: Strategy using 6 ml/kg tidal volume along with 10 cmH2O of PEEP was not associated with any significant improvement in gas exchange, hemodynamic parameters, or systemic inflammatory response over ventilation with 10 ml/kg volume without PEEP during laparoscopic cholecystectomy.

Comparison of combitube, easy tube and tracheal tube for general anesthesia.

BACKGROUND & AIMS: The Combitube(®) and EasyTube™ enable effective ventilation whether placed in the trachea or esophagus and can be used in prehospital settings, as well as in "Cannot Ventilate Cannot Intubate" situations in the operating room. Whether they can be continued to provide general anesthesia, if required, is not established. Thus the efficacy of Combitube and EasyTube was evaluated and compared with the tracheal tube for general anesthesia using controlled ventilation. MATERIALS AND METHODS: Combitube, EasyTube and tracheal tubes were used in 30 patients each to secure the airway in a randomized controlled manner. Ventilatory parameters were measured along with hemodynamic variables, and characteristics related to device placement. RESULTS: There was no significant difference in the various ventilatory parameters including minute ventilation requirement to maintain eucapnia amongst the three groups at any time point. There was no hypoxia or hypercarbia in any patient at any time. Placement of EasyTube was more difficult (P = 0.01) as compared with both Combitube and tracheal tube. EasyTube and Combitube resulted in higher incidence of minor trauma than with a tracheal tube (P = 0.00). CONCLUSION: Combitube and EasyTube may be continued for general anesthesia in patients undergoing elective nonlaparoscopic surgeries of moderate duration, if placed for airway maintenance. Given the secondary observations regarding placement characteristics of the airway devices, it, however cannot be concluded that the devices are a substitute for endotracheal tube for airway maintenance per se, unless specifically indicated.

Minimum effective volume of normal saline for epidural volume extension.

BACKGROUND: Rescue strategies like changes in tilt of table are used to raise the level of an inadequate sensory block following intrathecal injection. Epidural volume extension (EVE) refers to an injection of normal saline through epidural catheter following an intrathecal block. It results in a rapid increase in the sensory level of subarachnoid block. Thus, it has been postulated that EVE may be used as a rescue strategy for an inadequate post-spinal sensory block. However, the minimum effective volume (MEV) of normal saline for EVE induced increase in level of spinal block has not been researched till date. We proposed to determine the MEV of normal saline required for EVE induced increase in post-spinal block sensory level. MATERIALS AND METHODS: This prospective sequential allocation study was conducted in consenting adult males after institutional ethical committee approval scheduled for lower limb surgery under combined spinal epidural (CSE) anesthesia, who had an inadequate level of sensory block. Herein, an inadequate level was defined as lower than T10 at 10 min after the intrathecal injection, with no ascent for two consecutive readings taken 2 min apart. The EVE was performed with normal saline injected through epidural catheter, and was considered successful if the level of sensory block increased by two or more dermatomal segments within 5 min of the injection. The volume of normal saline for EVE was decided by using the up-and-down method, with the first patient receiving 10 mL and a dosing interval of 1 mL in subsequent patients. The analysis was done using the formula of Dixon and Massey, which enabled calculation of the MEV with 95% CI. Quantitative parametric data is represented as mean ± SD and nonparametric data as median (range). RESULTS AND CONCLUSION: The MEV of normal saline to raise the level of sensory block by two or more dermatomal segments within 5 min of EVE is 7.4 mL (95% CI: 5.5-9.9 mL).