Preoperative measurement of maternal abdominal circumference relates the initial sensory block level of spinal anesthesia for cesarean section: An observational study

The impact of height on the spread of spinal anesthesia and stress response in parturients undergoing caesarean section: a prospective observational study

Background

The spread of spinal anesthesia was influenced by many factors, and the effect of body height on spinal anesthesia is still arguable. This study aimed to explore the impact of height on the spread of spinal anesthesia and the stress response in parturients.

Methods

A total of ninety-seven parturients were allocated into two groups according to their height: the shorter group (body height was shorter than 158 cm) and taller group (body height was taller than 165 cm). Spinal anesthesia was performed with the same amount of 12 mg plain ropivacaine in mothers of different heights. The primary outcome of the study was the success or failure of the spinal anesthesia. The secondary outcomes of the study were stress response, time to T6 sensory level, the incidence of hypotension, the satisfaction of abdominal muscle relaxation and patient VAS scores.

Results

The rate of successful spinal anesthesia in the shorter group was significantly higher than that in the taller group (p = 0.02). The increase of maternal cortisol level in the shorter group was lower than that in the taller group at skin closure (p = 0.001). The incidence of hypotension (p = 0.013), time to T6 sensory block (p = 0.005), the quality of abdominal muscle relaxation (p <  0.001), and VAS values in stretching abdominal muscles and uterine exteriorization (p <  0.001) in the shorter group were significantly different from those in the taller group. Multivariate analysis showed that vertebral column length (p <  0.001), abdominal girth (p = 0.022), amniotic fluid index (p = 0.022) were significantly associated with successful spinal anesthesia.

Conclusions

It’s difficult to use a single factor to predict the spread of spinal anesthesia. Patient’s vertebral column length, amniotic fluid index and abdominal girth were the high determinant factors for predicting the spread of spinal anesthesia.

Trials registration

ChiCTR-ROC-17012030 (Chictr.org.cn), registered on 18/07/2017.

Prediction of spinal anesthesia-induced hypotension during elective cesarean section: a systematic review of prospective observational studies

BACKGROUND

Spinal anesthesia is the standard for elective cesarean section but spinal anesthesia-induced hypotension remains an important problem. Accurate prediction of hypotension could enhance clinical decision-making, alter management, and facilitate early intervention. We performed a systematic review of predictors of spinal anesthesia-induced hypotension and their predictive value during cesarean section.

METHODS

PubMed, Embase, Cochrane Library, Google Scholar and Web of Science databases were searched for prospective observational studies assessing the diagnostic accuracy of predictors of spinal anesthesia-induced hypotension in elective cesarean section. The quality of studies was assessed and predictors were grouped in domains based on the type of predictor.

RESULTS

Thirty-eight studies (n=3086 patients) were included. In most studies, patients received 500-1000 mL crystalloid preload or 500-2000 mL crystalloid coload. Vasopressors for post-spinal hypotension were boluses of ephedrine 5-15 mg and/or phenylephrine 25-100 µg in most studies. The hypotension rate varied from 29% to 80% based on the definition. For analysis, >30 predictors were classified into seven domains: demographic characteristics, baseline hemodynamic variables, baseline sympathovagal balance, postural stress testing, peripheral perfusion indices, blood volume and fluid responsiveness indices, and genetic polymorphism.

CONCLUSIONS

Environmental and individual factors increased outcome variability, which restricted the value of the autonomic nervous system and peripheral perfusion indices for prediction of spinal anesthesia-induced hypotension. Supine stress tests may reflect parturients' cardiovascular tolerance during hemodynamic fluctuations and may optimize the predictive value of static state predictors. Future research for predicting spinal anesthesia-induced hypotension should focus on composite and dynamic parameters during the supine stress tests.

Relationship between Abdominal Circumference and Incidence of Hypotension during Cesarean Section under Spinal Anesthesia

Background

Enlarged uterus can compress the inferior vena cava and cause hypotension when lying supine. Previous studies have shown a positive association between the abdominal circumference and size of the uterus. Therefore, the aim of this study was to evaluate the relationship between abdominal circumference and incidence of hypotension during cesarean section under spinal anesthesia.

Methods

The study cohort comprised women undergoing cesarean section under spinal anesthesia. Patients were divided into two groups according to the median abdominal circumference (<101 cm and ≥101 cm). Hypotension was defined as a systolic blood pressure of <90 mmHg or mean arterial pressure of <65 mmHg. The primary outcome of this study was the relationship between the incidence of hypotension and the abdominal circumference after spinal anesthesia in term pregnant women.

Results

The study cohort comprised 100 women. The incidence of hypotension did not differ between the groups (71.42% in the smaller vs. 78.43% in the larger abdominal circumference group, p=0.419). However, the decrease in mean arterial pressure and its percentage decrease from baseline were greater in the larger than in the smaller abdominal circumference group (change in mean arterial pressure: 28.33 mmHg (18.66-33.67) in the smaller vs. 36.67 mmHg (23.34-43.34) in the larger abdominal circumference group, p=0.004; percentage decrease: 31.41% (22.74-39.22) in the smaller vs. 38.47% (28.00-44.81) in the larger abdominal circumference group, p=0.022).

Conclusions

Large abdominal circumference in pregnancy is associated with greater decreases in mean arterial pressure from baseline. However, the incidence of hypotension defined by standard criteria did not differ between larger and smaller abdominal circumference groups.

The effects of uterine size with or without abdominal obesity on spinal block level and vasopressor requirement in elective cesarean section: a prospective observational study

Background/aim

Hypotension is a serious complication caused by spinal anesthesia that places both the mother and fetus at increased risk. We aimed to investigate the effects of uterine size with or without abdominal obesity on sensory block level of pregnant women receiving spinal anesthesia.

Materials and methods

This study included 125 term parturients who underwent cesarean section. Motor and sensory block characteristics, the distance between the symphysis pubis and the fundus (SPF), the distance between the symphysis pubis and the xiphoid (SPX), newborn and placental weights, adverse effects, and doses of ephedrine were recorded.

Results

Sensory block level and ephedrine dose were significantly correlated with the SPX and the combined newborn and placenta weights (P < 0.05). The incidence of hypotension was related to the SPX and the combined newborn and placenta weight (P < 0.05). There was no correlation between the SPF and sensory block level or ephedrine dose. The sensory block level was higher for patients who had greater SPX values and higher combined newborn and placenta weights. The incidence of hypotension and the ephedrine dose were also higher in these subjects.

Conclusion

SPX values and combined newborn and placenta weights are more predictive of sensory block level than SPF values in parturients receiving spinal anesthesia.

Correlation between Weight of the Baby and the Level of Sensory Blockade in Spinal Anaesthesia for Caesarean Section: An Observational Study

Background

The spread of local anaesthetics during spinal anaesthesia is affected by various factors and can be unpredictable especially in parturients undergoing caesarean section. Factors like abdominal girth, symphysis fundal height etc have to studied to know their impact on level of sensory blockade. We hypothesized a study to find any correlation between weight of the baby and the level of sensory blockade.

Methods

46 parturients posted for elective caesarean section belonging to American Society of Anaesthesiologists (ASA) physical status 1 and 2 were included in the study. Maternal height and weight were noted down before entering operation theatre. All patients were instituted subarachnoid block with 2 cc of 0.5% of hyperbaric bupivacaine in sitting position. Level of sensory blockade was assessed with pin prick along midline of the patient every min till 5^th minute and 5 minutes till 15^th minute. The birth weight of baby was recorded soon after delivery.

Results

The weight of the baby and height of the mother were correlated with the sensory blockade of T4. The number of babies weighing more than 3.5 kgs were 3 in our study out of which 2 babies were associated with maximum sensory blockade at 15^th minute. It amounts to 66.7% when compared with 14.7% in babies weighing 2.5 to 3.5 kgs which is suggestive of significance ('P' value of 0.093).

Conclusion

There is no statistically significant correlation between weight of the baby and the level of sensory blockade.