European Journal of Cardiovascular Medicine

Patients undergoing lower abdominal surgeries including caesarean section require spinal anaesthesia to perform the surgical procedure.

Spinal anaesthesia (SA) is a frequently employed method for caesarean section. Hypotension is defined by a systolic pressure drop of more than 20% of the baseline, or a systolic blood pressure (SBP) less than 90 mm/Hg. There is an 80-83% incidence of spinal anaesthesia induced hypotension. It is because of venous pooling due to sympathetic blockade and also due to the vascular tone being reduced by progesterone, and poses a risk to the mother, foetus, and infant. The degree of hypotension depends upon various factors like height of the block, position of the patient, volume and concentration of the drug and type of surgery.  Post spinal hypotension can be managed effectively by relieving aortocaval compression, loading the patient with intravenous fluids, sequential compression devices (SCD), vasopressors, ionotropic agents.1,2

Preloading with crystalloid solution or the use compression devices can be done in order to reduce the hypotension. We intend to study the effectiveness of both crystalloid preloading and sequential compression device in reducing spinal induced hypotension in caesarean section.

Lacuna in Knowledge

Early detection can reduce adverse events such as reduced uterine blood flow and foetal acidosis.1,3 Hypotension is one of the most frequent side effect of spinal anaesthesia. It is due to loss of vascular tone due to sympatholysis which leads to reduced venous return to the heart. This is more pronounced in the obstetric patients due to the presence of the gravid uterus and effects of progesterone.

There are many studies found in literature with regard to effectiveness of crystalloid preloading in reducing post spinal hypotension. But there are not many studies done to prove the effectiveness of SCD in reducing post spinal hypotension. Therefore, we aim to evaluate the effectiveness of crystalloid preload and SCD in lowering hypotension following spinal anaesthesia in elective caesarean sections.

Objectives:

Primary- To determine the effectiveness of sequential compression devices in reducing incidence of hypotension after spinal anaesthesia in elective caesarean section.

Secondary- To compare and assess the role of crystalloid preload in reducing incidence of hypotension after spinal anaesthesia with sequential compression devices.

Adult patients with an anticipated difficult intubation undergoing scheduled surgery who required tracheal intubation with general anaesthesia were prospectively included in the study after informed consent taken Study Design: A Randomized control study Sample Size: 46(23 in each group) Formula n = (Z1-α/2+Z1-β)2 × ((P1×(1-P1)+P2×(1-P2)) / (P1-P2)2 Where: n = Sample size, Z1-α/2 = 1.96 when α = 5% for two-tailed hypothesis, Z1-β = 0.842 when β = 20% (test power = 80%), P = Probability of the main outcome. Duration of study: 18 months Study Participants: This study was conducted on patients posted for Elective Caesarean sections at R. L. Jalappa Hospital and Research Centre, Tamaka, Kolar. Sampling Method: Computer generated random sequence of numbers and concealed by closed envelope technique. Inclusion Criteria • Patients more than 18 years of age with American Society of Anaesthesiologists (ASA) physical status 2 posted for elective caesarean section under spinal anaesthesia. Exclusion Criteria • Allergic to Local anaesthetic • Coagulopathy- platelet count < 80,000/mm3, INR > 1.5, PT > 4 sec control and APTT > 10 sec control • Infection at the site of injection • Neurological deficits like paraplegia and paresis of lower limb SAMPLING PROCEDURE: • 1. The study was started after Institutional Ethical Clearance (IEC). Patients included in the study after obtaining written, informed consent. Study was conducted on patients more than 18 years of age undergoing elective caesarean section. Necessary investigations like Platelet count, PT, INR and APTT are done prior to surgical procedure. • Peripheral Intravenous cannula was secured and IV fluids (Ringer’s Lactate) was initiated. • Patients in both groups were premedicated with the following medications 15minutes before the procedure. 1. Inj. Ranitidine 50mg IV 2. Inj. Ondansetron 4mg IV. 3. Patients were divided into two groups using computer generated random number table • Group S: Sequential compression device group • Group C: Crystalloid Group • Group C – Patients were preloaded with Ringer Lactate (RL) at 10ml/kg over 10 minutes. • After preloading the patient, subarachnoid block was given and crystalloid (RL) continued at 2ml/kg/hour during the intraoperative period. • Group S – Sequential compression device was applied and compressions initiated at 60mmHg prior to the subarachnoid block. 2ml/kg/hour of maintenance fluid was continued during the surgical procedure. • In the Operation Theatre, routine monitors like pulse-oximeter, electrocardiogram, non-invasive blood pressure (NIBP), temperature monitoring was connected and monitored throughout the procedure. • In the sitting position, L3-L4 interspace was identified and 2% Xylocaine was used for skin infiltration. Subarachnoid block was performed using 25-gauge Quincke’s needle. After confirming the subarachnoid space and free flow of clear CSF, 2ml of 0.5% Hyperbaric Bupivacaine was injected intrathecally. • Following the procedure, patients were positioned supine with 15-20 degree left lateral tilt. Level of blockade was assessed using pinprick test. • Oxygen with face mask (3-5 liter/minute) was given, if the patient saturation is <95%. NIBP was measured every 3 minutes until delivery and thereafter every 5 minutes during the intraoperative period • In the event of maternal hypotension (drop in SBP by 20% of the baseline or SBP < 90mmHg) was treated with Inj. Mephentermine 3mg boluses. • If bradycardia occurs (Heart rate <60 beats per minute), patients were treated with Inj. Glycopyrrolate 0.2mg i.v. • After delivery Inj. Oxytocin 3 IU i.v stat was given and infusion was started at the rate of 10 IU/hour for 2hours. • At the end of the surgery, sequential compression device was removed from patients in Group S and the level of block were reassessed. Parameters to be observed • Heart rate • SBP and mean arterial pressure (MAP) • Oxygen saturation • Electrocardiogram • Urine Output STATISTICAL ANALYSIS All the data were entered in excel sheet and analyzed using SPSS v23.0 operating on windows 10. The data were summarized as mean, standard deviation, frequency and percentage. The summarized data were represented using tables, figures, bar diagram and pie chart. The mean difference between continuous data were compared using unpaired t-test and categorical data using chi-square test. For all statistical purpose, a p-value of <0.05 was considered statistically significant.

In present study total 60 patients fulfilling inclusion criteria are included with overall mean age of 26.8±3.5yrs. patients were divided into two groups as per the procedure of study criteria and grouped as 30 patients in crystalloid and other 30 patients SCD.

Table 1: Comparison of the mean age between the groups

The mean age of patients between the group were comparable with no significant difference noted.

Table 2: Comparison of the heart rate between the groups

On assessment of the heart rate, there is no significant difference noted in mean heart rate changes between the group at various interval of time.

Table 3: Comparison mean systolic blood pressure between the groups.

On assessment of the systolic blood pressure, there is no significant difference noted in mean heart rate changes between the group at various interval of time. However, there is significant drop in systolic blood pressure at 6^th to 12^th min of interval in crystalloid group compared to SCD.(p<0.05)

Table 4: Comparison of mean diastolic blood pressure between the groups

On assessment of the diastolic blood pressure, there is no significant difference in the mean level between the group at various interval of time. However, there is significant lower mean DBP in group SCD at 55^th and 60^th min. (p<0.05)

Table 5: Comparison of the additional treatment required between the groups

On assessment of additional treatment, there is no much significant difference in the distribution at different interval of time. However, there was significant higher incidence of requirement of the additional treatment in crystalloid group at 6^th min compared to SCD group.

Post-spinal hypotension is a prevalent complication during caesarean sections, posing significant risks to both the mother and foetus, including compromised placental perfusion and foetal distress. Various strategies are employed to mitigate this issue, primarily focusing on maintaining adequate blood pressure levels. Among these, the use of Crystalloid preload and Sequential compression devices (SCDs) are two common approaches. Crystalloid preload involves administering intravenous fluids to increase circulating blood volume before the onset of anaesthesia, aiming to prevent the anticipated drop in blood pressure. Conversely, Sequential compression devices (SCDs) mechanically enhance venous return by intermittently compressing the lower limbs, thereby supporting cardiovascular stability during anaesthesia. This study compares the effectiveness of these two interventions in managing post-spinal hypotension during caesarean sections, assessing their impacts on hemodynamic stability and the need for additional treatments.

The current study includes 60 patients in total who match the inclusion criteria.

having a mean age of 26.8±3.5 years overall. According to the study's protocol, the patients were split into two groups: thirty patients were classified as SCD patients and the remaining thirty as crystalloid patients. There was no discernible variation in the mean age of the patients in the group.

Assessments of blood pressure and heart rate show no discernible differences between the groups. However, there is significant drop in systolic blood pressure at 6th to 12th min of interval in crystalloid group compared to SCD (p<0.05).

Similar to the current study, Agarwal A et al., documented the drop in systolic blood pressure from the initial level was notably higher in the crystalloid group (p=0.043).

In conclusion, sequential compression device use proves beneficial in averting hypotension among expectant mothers undergoing elective caesarean section with spinal anaesthesia.2

Bhardwaj N et al., found that the prevention of maternal hypotension following subarachnoid block, co-loading of crystalloid fluid is superior than preloading of crystalloids.15 Study by Javaherforooshzadeh F et al., found that three minutes following spinal anaesthesia, the SCD group exhibited notably higher diastolic blood pressure when compared to the control group (P < 0.05). 16

According to a study by Sujata Na et al., the frequency and severity of hypotension following spinal anaesthesia for caesarean delivery were found to be reduced by using a mechanical sequential compression pump that detects venous refilling and adjusts accordingly. 17

On assessment of additional treatment, there is no much significant difference in the distribution at different interval of time. However, there was significant higher incidence of requirement of the additional treatment in crystalloid group at 6th min compared to SCD group.

In line study by Javaherforooshzadeh F et al., documented with the SCD group displayed significantly reduced incidences of nausea (P = 0.005) and vomiting (P =0.001) compared to the control group. Furthermore, the SCD group demonstrated a substantially lower average ephedrine dosage per patient (4.1 mg versus 17.1 mg, P = 0.001).16 In study by Zadeh FJ et al, the research indicates that employing Sequential Compression Device (SCD) effectively reduces hypotension following spinal anaesthesia for caesarean section. Additionally, it suggests that this method may lead to a decrease in the required dosage of vasopressors to increase blood pressure. However, further studies with larger sample sizes are needed to confirm its effectiveness definitively. 3

In conclusion, Sequential Compression Devices appear to be more effective than Crystalloid Preload in mitigating early post-spinal hypotension during caesarean sections, making them a preferable option in this clinical scenario. Further research might focus on the long-term outcomes and patient comfort associated with each method to optimize perioperative care in caesarean sections.

1.      Prajith KR, Mishra G, Ravishankar M, Kumar VRH. Hemodynamic changes under            spinal anesthesia after elastic wrapping or pneumatic compression of lower limbs in         elective caesarean section: a randomized control trial. J Anaesthesiol Clin Pharmacol.                 2020;36(2):244–50.

2.      Agarwal A, Singh VK, Singh V, Singh GP. Use of sequential compression device for prevention of hypotension associated with spinal anesthesia in elective caesarean section. Indian J Obs Gynecol Res. 2022;9(1):48–53.

3.      Zadeh FJ, Alqozat M, Zadeh RA. Sequential compression pump effect on hypotension due to spinal anesthesia for caesarean section: a doubleblind clinical trial. Electron physician. 2017;9(5):4419–22.

4.      Olawin AM, M Das J. Spinal Anesthesia. In Treasure Island (FL); 2024.

5.      Olawin AM. Spinal anesthesia. StatPearls [Internet]. 2022. p. 1–10.

6.      Saifuddin A, Burnett SJ, White J. The variation of position of the conus medullaris in an adult population. A magnetic resonance imaging study. Spine (Phila Pa 1976). 1998 Jul;23(13):1452–6.

7.      Broadbent CR, Maxwell WB, Ferrie R, Wilson DJ, Gawne-Cain M, Russell R. Ability of anaesthetists to identify a marked lumbar interspace. Anaesthesia. 2000 Nov;55(11):1122–6.

8.      Tewfik G, Hesketh P, Chinn L, Srinivasan N, Abdelmalek A. Simulated anesthesia consent discussions demonstrate high level of comprehension and education requirements for patients: A pilot study. PEC Innov. 2023 Dec; 2:100153.

9.      Carpenter RL, Caplan RA, Brown DL, Stephenson C, Wu R. Incidence and risk factors for side effects of spinal anesthesia. Anesthesiology. 1992 Jun;76(6):906–16.

10.   Hartmann B, Junger A, Klasen J, Benson M, Jost A, Banzhaf A, et al. The incidence and risk factors for hypotension after spinal anesthesia induction:  an analysis with automated data collection. Anesth Analg. 2002 Jun;94(6):1521–9, table of contents.

11.   Ashken T, West S. Regional anaesthesia in patients at risk of bleeding. BJA Educ. 2021 Mar;21(3):84–94.

12.   Kako H, Beltran RJ, Krishna SG, Bhalla T, Tobias JD. Neuraxial anesthesia in the presence of clinical anticoagulation: what are our options for pediatric patients? Vol. 8, International journal of clinical and experimental medicine. United States; 2015. p. 1475–81.

13.   Halpern S, Preston R. Postdural puncture headache and spinal needle design. Metaanalyses. Anesthesiology. 1994 Dec;81(6):1376–83.

14.   Zaric D, Pace NL. Transient neurologic symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics. Cochrane database Syst Rev. 2009 Apr;(2):CD003006.

15.   Bhardwaj N, Thakur A, Sharma A, Kaushal S, Kumar V. Comparative Study between Crystalloid Preloading and Coloading for Prevention of Hypotension in Elective Caesarean Section Under Spinal Anesthesia in a Secondary Care Hospital. Int J Res Rev. 2020;7(7):2454–2237.

16.   16.     Javaherforooshzadeh F, Pipelzadeh MR, Akhondzadeh R, Adarvishi S, Alghozat M. Effect of Sequential Compression Device on Hemodynamic Changes After Spinal Anesthesia for Caesarean Section: A Randomized Controlled Trial. Anesthesiol pain          Med. 2020 Oct;10(5):e104705.

Sujata N, Arora D, Panigrahi BP, Hanjoora VM. A Sequential Compression Mechanical          Pump to Prevent Hypotension During Elective Caesarean Section Under Spinal        Anesthesia. Obstet Anesth Dig [Internet]. 2013;33(2):117–8