Preoperative echocardiography as a predictor of spinal anesthesia-induced hypotension in older patients with mild left ventricular diastolic dysfunction: a retrospective observational study

BACKGROUND

Spinal anesthesia-induced hypotension (SAH) frequently occurs in older patients, many of whom have mild left ventricular (LV) diastolic dysfunction, often asymptomatic at rest. This study investigated the association between preoperative echocardiographic measurements and SAH in older patients with mild LV diastolic dysfunction.

METHODS

We conducted a retrospective observational study using data from electronic medical records. The patients ≥ 65 years old who underwent spinal anesthesia for urologic surgery between January 2016 and December 2017 and whose preoperative echocardiography within 6 months before surgery revealed grade I LV diastolic dysfunction were recruited. SAH was investigated using the anesthesia records. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

A total of 163 patients were analyzed. SAH and significant SAH developed in 55 (33.7%) patients. The mitral inflow E velocity was an independent risk factor for SAH (odds ratio [OR], 0.886; 95% confidence interval [CI], 0.845-0.929; P < 0.001). The area under the ROC curve for mitral inflow E velocity to predict SAH was 0.819 (95% CI, 0.752-0.875; P < 0.001). If mitral inflow E velocity was ≤ 60 cm/s, SAH was predicted with a sensitivity of 83.6% and specificity of 70.4%.

CONCLUSIONS

The preoperative mitral inflow E velocity demonstrated the greatest predictability of SAH in older patients with mild LV diastolic dysfunction. This may assist in identifying patients at high risk of SAH and guiding preventive strategies in the future.

Rider sitting position widens lumbar intervertebral distance: a prospective observational study

BACKGROUND

Reduced lumbar lordosis may make the process of identifying the intervertebral distance easier. The primary aim of this study was to measure the L3...L4 intervertebral space in the same patients undergoing spinal anesthesia in three different sitting positions, including the classic sitting position (CSP), hamstring stretch position (HSP) and rider sitting position (RSP). The secondary aim was to compare ultrasonographic measurements of the depth of the ligamentum flavum and intrathecal space in these three defined positions.

METHODS

This study is a single-blinded, prospective, randomized study. Ninety patients were included in final analysis. the patients were positioned on the operating table in three different positions to perform ultrasonographic measurements of the spinal canal. The intervertebral distance (IVD), the distance between the skin and the ligamentum flavum (DBSLF) and the intrathecal space (IS) were measured in the L3...L4 intervertebral space in three different positions.

RESULTS

The RSP produced the largest mean distance between the spinous processes. The RSP yielded a significantly larger IVD than did the CSP (p < 0.001) and HSP (p < 0.001). The DBSP was larger in the CSP than in the HSP (p = 0.001). The DBSLF was significantly larger in the RSP than in the HSP (p = 0.009).

CONCLUSIONS

Positioning the patient in the RSP significantly increased the intervertebral distance between L3...L4 vertebrae compared to the CSP and HSP, suggesting easier performance of lumbar neuraxial block.

Anesthesia characteristic of an algorithm of bupivacaine dose based on height in caesarean section under spinal anesthesia: a retrospective cohort study

BACKGROUND

An algorithm of bupivacaine dose based on height is applied to reduce maternal hypotension in caesarean section under spinal anesthesia. This study is designed to further verify whether the algorithm of bupivacaine dose based on height is suitable.

METHODS

The parturients were grouped according to height. The comparison of anesthesia characteristic among subgroups was carried out. The univariate and multivariate binary logistic regressions were executed to reanalyze the interference factor for the anesthesia characteristic.

RESULTS

When the dose of bupivacaine was adjusted by using the height based dosing algorithm, except for weight (P < 0.05), other general data did not present statistical changes with height (P > 0.05); the incidences of complications, characteristics of sensory or motor block, quality of anesthesia and neonatal outcome were of no statistical difference among parturients with different heights (P > 0.05); the height, weight and body mass index were not related with maternal hypotension (P > 0.05). When the dose of bupivacaine is constant, except for weight and body mass index (P > 0.05), the height was the independent risk factor for maternal hypotension (P < 0.05).

CONCLUSIONS

Except for weight and body mass index, the height has an influence on the bupivacaine dose. It is reasonable that the bupivacaine dose is adjusted by using this dosing algorithm based on height.

TRIAL REGISTRATION

This study was registered at http://clinicaltrials.gov (13/04/2018, NCT03497364).

Safety and effectiveness of adding fentanyl or sufentanil to spinal anesthesia: systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Spinal infusions of either fentanyl or sufentanil have been reported in international reports, articles, and scientific events worldwide. This study aimed to determine whether intrathecal fentanyl or sufentanil offers safety in mortality and perioperative adverse events.

METHODS

MEDLINE (via PubMed), EMBASE, CENTRAL (Cochrane library databases), gray literature, hand-searching, and clinicaltrials.gov were systematically searched. Randomized controlled trials with no language, data, or status restrictions were included, comparing the effectiveness and safety of adding spinal lipophilic opioid to local anesthetics (LAs). Data were pooled using the random-effects models or fixed-effect models based on heterogeneity.

RESULTS

The initial search retrieved 4469 records; 3241 records were eligible, and 3152 articles were excluded after reading titles and abstracts, with a high agreement rate (98.6%). After reading the full texts, 76 articles remained. Spinal fentanyl and sufentanil significantly reduced postoperative pain and opioid consumption, increased analgesia and pruritus. Fentanyl, but not sufentanil, significantly reduced both postoperative nausea and vomiting, and postoperative shivering; compared to LAs alone. The analyzed studies did not report any case of in-hospital mortality related to spinal lipophilic opioids. The rate of respiratory depression was 0.7% and 0.8% when spinal fentanyl or sufentanil was added and when it was not, respectively. Episodes of respiratory depression were rare, uneventful, occurred intraoperatively, and were easily manageable.

CONCLUSION

There is moderate to high quality certainty that there is evidence regarding the safety and effectiveness of adding lipophilic opioids to LAs in spinal anesthesia.

Hemodynamic changes in patients with SARS-CoV-2 infection presenting for cesarean delivery under spinal anesthesia: a retrospective case-control study

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with adverse maternal and neonatal outcomes. Early studies suggested that COVID-19 was associated with a higher incidence of hypotension following neuraxial anesthesia in parturients. We explored the hemodynamic response to spinal anesthesia for cesarean delivery in pregnant severe respiratory distress syndrome-coronavirus-2 (SARS-CoV-2) positive patients, using a retrospective case-control design.

METHODS

We searched our electronic medical records for patients who received spinal anesthesia for cesarean delivery, and were SARS-CoV-2 positive or recovered at delivery, and used historical and SARS-CoV-2 negative controls from two tertiary care hospitals. We compared the demographic, clinical, and hemodynamic variables between patients who were SARS-CoV-2 positive at delivery, those who were positive during pregnancy and recovered before delivery, and controls. Analyses were stratified by normotensive versus hypertensive status of the patients at delivery.

RESULTS

We identified 22 SARS-CoV-2 positive, 73 SARS-CoV-2 recovered, and 1517 controls. The SARS-CoV-2 positive, and recovered pregnant patients, had on average 5.6 and 2.2 mmHg, respectively, higher post-spinal mean arterial pressures (MAPs) than control patients, adjusting for covariates. Additionally, the lowest post-spinal MAP was negatively correlated with the number of daysbetween the onset of COVID-19 symptoms and delivery in patients with hypertension (correlation -0.55, 95% CI -0.81 to -0.09).

CONCLUSIONS

Patients with SARS-CoV-2 infection during pregnancy exhibit less spinal hypotension than non-infected patients. While the clinical significance of this finding is unknown, it points to important cardiovascular effects of the virus.

Comparison of the effects of dexmedetomidine and propofol on hypothermia in patients under spinal anesthesia: a prospective, randomized, and controlled trial

Background: Redistribution hypothermia caused by vasodilation during anesthesia is the primary cause of perioperative hypothermia. Propofol exerts a dose-dependent vasodilatory effect, whereas dexmedetomidine induces peripheral vasoconstriction at high plasma concentrations. This study compared the effects of dexmedetomidine and propofol on core temperature in patients undergoing surgery under spinal anesthesia. Methods: This prospective study included 40 patients (aged 19-70 years) with American Society of Anesthesiologists Physical Status class I-III who underwent elective orthopedic lower-limb surgery under spinal anesthesia. Patients were randomly allocated to a dexmedetomidine or propofol group (n = 20 per group). After induction of spinal anesthesia, patients received dexmedetomidine (loading dose: 1 μg/kg over 10 min; maintenance dose: 0.2-0.7 μg/kg/h) or propofol (loading dose: 75 μg/kg over 10 min; maintenance dose: 12.5-75 μg/kg/min). The doses of sedatives were titrated to maintain moderate sedation. During the perioperative period, tympanic temperatures, thermal comfort score, and shivering grade were recorded. Results: Core temperature at the end of surgery did not differ significantly between the groups (36.4 ± 0.4 and 36.1 ± 0.7°C in the dexmedetomidine and propofol groups, respectively; P = 0.118). The lowest perioperative temperature, incidence and severity of perioperative hypothermia, thermal comfort score, and shivering grade did not differ significantly between the groups (all P > 0.05). Conclusions: In patients undergoing spinal anesthesia with moderate sedation, the effect of dexmedetomidine on patients' core temperature was similar to that of propofol.

Association between anesthetic method and postpartum hemorrhage in Korea based on National Health Insurance Service data

Background

Postpartum hemorrhage (PPH) is a major cause of maternal mortality and the risk factors for PPH differ among studies. In this large-scale study, we investigated whether the anesthetic method used was associated with PPH after cesarean section.

Methods

We extracted data on cesarean sections performed between January 2008 and June 2013 from the National Health Insurance Service database. The anesthetic methods were categorized into general, spinal and epidural anesthesia. To compare the likelihood of PPH among deliveries using different anesthetic methods, crude and adjusted odds ratios (ORs) and 95% confidence intervals were calculated using logistic regression analysis.

Results

Data from 330,324 cesarean sections were analyzed, and 21,636 cases of PPH were identified. Univariate analysis showed that general and epidural anesthesia increased the risk of PPH compared to spinal anesthesia. The OR for PPH was highest for morbidly adherent placenta, followed by placenta previa, placental abruption, and hypertension. When other clinical covariates were controlled for, general and epidural anesthesia still remained significant risk factors for PPH compared to spinal anesthesia.

Conclusions

This study showed that general and epidural anesthesia elevated the risk of PPH compared to spinal anesthesia during cesarean section. Since we could not consider the potential bias of group differences in indications, more in-depth clinical trials are needed to validate our findings. Obstetric factors such as placental abnormalities had high odds ratios and thus are more important than the choice of anesthetic method, which should be based on the patient's clinical condition and institutional resources.

Verification of the performance of the Bispectral Index as a hypnotic depth indicator during dexmedetomidine sedation

Background

Differences in the effects of propofol and dexmedetomidine sedation on electroencephalogram patterns have been reported previously. However, the reliability of the Bispectral Index (BIS) value for assessing the sedation caused by dexmedetomidine remains debatable. The purpose of this study is to evaluate the correlation between the BIS value and the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale in patients sedated with dexmedetomidine.

Methods

Forty-two patients aged 20–80 years, who were scheduled for surgery under spinal anesthesia were enrolled. Spinal anesthesia was performed using 0.5% bupivacaine, which was followed by dexmedetomidine infusion (loading dose, 0.5–1 μg/kg for 10 min; maintenance dose, 0.3–0.6 μg/kg/h). The MOAA/S score was used to evaluate the level of sedation.

Results

A total of 215082 MOAA/S scores and BIS data pairs were analyzed. The baseline variability of the BIS value was 7.024%, and BIS value decreased, as the MOAA/S scored decreased. The correlation coefficient and prediction probability between the two measurements were 0.566 (P < 0.0001) and 0.636, respectively. The mean ± standard deviation values of the BIS were 87.22 ± 7.06, 75.85 ± 9.81, and 68.29 ± 12.65 when the MOAA/S scores were 5, 3, and 1, respectively. Furthermore, the cut-off BIS values in the receiver operating characteristic analysis at MOAA/S scores of 5, 3, and 1 were 82, 79, and 73, respectively.

Conclusions

The BIS values were significantly correlated with the MOAA/S scores. Thus, the BIS along with the clinical sedation scale might prove useful in assessing the hypnotic depth of a patient during sedation with dexmedetomidine.

Associated factors with umbilical arterial pH after cesarean delivery under spinal anesthesia: a retrospective cohort study

BACKGROUND

Maximum decrease of blood pressure and number of minutes of hypotension were independently associated with umbilical arterial pH. However, the impact of hypotension considering the duration of it on umbilical arterial pH is unknown.

METHODS

Pregnant women aged ≥ 20 years who delivered a baby at full-term via a cesarean delivery under a single-shot spinal anesthesia between January 2017 and March 2019 were included. The main outcome was to predict umbilical arterial pH, based on the value of the time integral of hypotension. Patient demographics, patient comorbidities, and intraoperative data, including the total dose of ephedrine and phenylephrine by fetal delivery and cumulative duration of maternal hypotension, were evaluated. Maternal hypotension was reflected as a decrease in systolic arterial pressure and mean arterial pressure to < 80% of baseline values. The systolic arterial pressure and mean arterial pressure were independently included in a multiple regression analysis along with all other explanatory factors to predict the umbilical arterial pH.

RESULTS

Of the 416 eligible patients, 381 were enrolled. When including the systolic arterial pressure or mean arterial pressure in the model, emergency cases, the total dose of ephedrine, hypertensive disorders of pregnancy, and systolic arterial pressure or mean arterial pressure values were found to be significant predictive factors of umbilical arterial pH.

CONCLUSION

Our results suggest that an elevated time integral of maternal hypotension may have a negative impact on umbilical arterial pH. Therefore, to minimize the risk of fetal acidosis, maternal hypotension should be prevented with the consideration of vasopressors selection.

Ultrasonography for lumbar neuraxial block

Ultrasonography can be useful to perform a lumbar neuraxial block. It aids in understanding the anatomy of the lumbar spine before the procedure. Pre-procedural ultrasound imaging provides information about the accurate intervertebral level for puncture, optimal needle insertion point, and depth of needle advancement for a successful neuraxial block. The key ultrasonographic views for lumbar neuraxial block include the transverse midline interlaminar and parasagittal oblique views. Ultrasonography can facilitate lumbar neuraxial block in difficult cases, such as the elderly, obese patients, and patients with anatomical abnormality of the lumbar spine. This review elucidates the basics of spinal ultrasonography for lumbar neuraxial block and the current evidence regarding ultrasound-guided neuraxial block in adults.

Evaluation of changes in anesthetic methods for cesarean delivery: an analysis for 5 years using the big data of the Korean Health Insurance Review and Assessment Service

Background

As an anesthesia induced during cesarean section, spinal anesthesia is preferred over general and epidural anesthesia. This study aimed to review the trend of anesthetic methods for cesarean section based on data obtained from the Korean Health Insurance Review and Assessment Service from 2013 to 2018.

Methods

The anesthetic methods were analyzed in 753,285 parturients who underwent a cesarean section in Korea from 2013 to 2018. We determined the association between each anesthetic method and hospital type and maternal and fetal factors. We also evaluated whether the anesthetic method was associated with the parturients’ length of hospital stay.

Results

General anesthesia, spinal anesthesia, and epidural anesthesia were induced in 28.8%, 47.7%, and 23.6% of parturients from 2013 to 2018, respectively. Trend analyses showed that spinal anesthesia increased from 40.0% in 2013 to 53.7% in 2018. The opposite trend applied to general anesthesia, decreasing from 37.1% in 2013 to 22.2% in 2018. The factors that were significantly associated with the anesthetic method were parturient’s parity, emergency condition, gestational age, and fetal weight. The type of hospital, parturient’s age, and multiple birth were also associated with the anesthetic methods. There was a strong association between general anesthesia and hospital stay longer than 7 days.

Conclusions

Spinal anesthesia is currently the main anesthetic method used for cesarean delivery, and the rate of spinal anesthesia is gradually increasing in Korea.

The Effect of Ringer versus Haemaccel Preload on Incidence of Postoperative Nausea and Vomiting

INTRODUCTION

Postoperative nausea and vomiting (PONV) is the most common and unpleasant postoperative complication. There is much controversy on preoperative fluid therapy. The aim of this study was to examine the effect of crystalloid fluid (Ringer solution) versus colloid (Haemaccel solution) on the incidence of postoperative nausea and vomiting in patients receiving spinal anesthesia.

METHODS

In this double-blinded clinical trial, 46 patients were selected according to the inclusion and exclusion criteria. Patients were randomly allocated to one of two groups. The crystalloid group received Ringer solution at a volume of 7 ml/kg and colloid group received 7ml/kg of 3% Modified Gelatin (Haemaccel) as a preoperative intravenous bolus. We used a Verbal Rating Scale (VRS) for assessing the nausea and vomiting occurrence. Data were analyzed using SPSS software ver.13 and χ(2) test and independent t-test.

RESULTS

The result showed that the incidence of PONV was less frequent in both Ringer and Haemaccel groups, but the incidence of vomiting and the intensity of nausea was not significantly different in any time point after anesthesia.

CONCLUSION

We conclude that preoperative fluid administration decreases the incidence of PONV, and both Crystalloids (Ringer) and colloids (haemaccel) solution were found to be equivalent in prevention of PONV. Therefore using of either Ringer or haemaccel solution is recommended for prevention of PONV.

Anesthetic management of super-morbidly obese parturients for cesarean delivery with a double neuraxial catheter technique: a case series

Parturients with super-morbid obesity, defined as body mass index greater than 50kg/m(2), represent a growing segment of patients who require anesthetic care for labor and delivery. Severe obesity and its comorbid conditions place the parturient and fetus at greater risk for pregnancy complications and cesarean delivery, as well as surgical and anesthetic complications. The surgical approach for cesarean delivery in these patients may require a supra-umbilical vertical midline incision due to a large pannus. The dense T4-level of spinal anesthesia can cause difficulties with ventilation for the obese patient during the procedure, which can be prolonged. Patients also may have respiratory complications in the postoperative period due to pain from the incision. We describe the anesthetic management of three parturients with body mass index ranging from 73 to 95kg/m(2) who had a cesarean delivery via a supra-umbilical vertical midline incision. Continuous lumbar spinal and low thoracic epidural catheters were placed in each patient for intraoperative anesthesia and postoperative analgesia, respectively. Continuous spinal catheters were dosed with incremental bupivacaine boluses to achieve surgical anesthesia. In one case, the patient required respiratory support with non-invasive positive pressure ventilation. Two cases were complicated by intraoperative hemorrhage. All patients had satisfactory postoperative analgesia with a thoracic epidural infusion. None suffered postoperative respiratory complications or postdural puncture headache. The use of a continuous lumbar spinal catheter and a low thoracic epidural provides several advantages in the anesthetic management of super-morbidly obese parturients for cesarean delivery.