European Journal of Cardiovascular Medicine

As commonly observed, Shivering is a side effect seen after general anesthesia, which is seen in 5-65% and in 33% after regional anesthesia. The frequency of shivering during Caesarean section (C-section) under neuraxial anesthesia is 55% (1-3). Tremor is a reaction of skeletal muscles that cannot be increased for health reasons; increased carbon dioxide, lactate synthesis, increased heart rate, increased blood pressure, intraocular pressure and catecholamine release. It can be associated with blood pressure, oxygen saturation and electrocardiogram monitoring. Tremors can occur due to many reasons in patients with underlying disease, respiratory failure or heart failure (4). loss, compromise, pain and release of pyrogens (5-7). The main causes of intraoperative hypothermia are the interference with body temperature control by anesthesia, decreased body metabolism, exposure to cold air in the operating room, and an open body cavity (8). Hypothermia can inhibit platelet function and clotting factors, leading to increased bleeding. It also inhibits drug metabolism, delays muscle recovery, delays patient recovery, and delays hospitalization (9). Intrathecal anesthesia suppresses thermoregulatory mechanisms, leading to perioperative hypothermia and shivering as a thermoregulatory response to hypothermia (10). and shivering therapy. Nonmedical methods include warming the body surface, warming with blankets and warm water infusion. Pharmacological methods require opioids (e.g. pethidine and tramadol), ondansetron, and clonidine. The most common treatment, pethidine, has side effects that include nausea, vomiting, pruritus, and respiratory distress, especially when taken in high doses (11, 12). Tramadol can also cause seizures (13), while clonidine can cause hypotension, anxiety, bradycardia, hyperglycemia, nausea, and vomiting (14). DEXMED is a potent, selective alpha2-adrenoceptor agonist, eight times more potent than clonidine, and promotes sedation, anxiety relief, and anesthesia without causing respiratory depression. The anticonvulsant effect of DEX is due to its ability to bind to α2 receptors, causing vasoconstriction. It also has thermoregulatory effects on the hypothalamus (15-17). DEX appears to be effective in controlling tremors and has fewer side effects than traditional medications. The exact mechanisms by which DEX controls tremors are unclear and complex. DEX reduces tremors by inhibiting central thermoregulatory control, blocking neuronal transmission, inhibiting vasoconstriction, and reducing tremors (18). However, few studies have evaluated the efficacy of DEX, particularly its effect on the performance of body tremors during surgery. Hence this study was undertaken to evaluate the effect of DEX on shivering in patients undergoing C-sections after intrathecal anesthesia.

This study was done in a tertiary medical college in central India from 1stOctober 2022 to September 2023 on 160 female patients, posted for elective C-sections under intrathecal an aesthesia.

Adult patients of age 18-35 years, ASA grade 1 or 2 and weighing between 45 to 70kgposted for Caesarean section and giving consent for the procedure will be included in our study.

Exclusion criteria: Patients with history of seizures, allergies to our study medicines, febrile illness, coagulation disorders, any contraindication for intrathecal anesthesia, and severe cardiac, respiratory, hepatic, renal, and muscular diseases.

Spinal anesthesia was performed at the L3 - L4 or L4 - L5 space with an injection of 10 mg of bupivacaine 0.5% in a sitting position. Blocking was confirmed by pinprick test and foot movement. Patients were randomly divided into groups D and C. Randomization was undertaken using a random number table.

Patients were divided into 2 groups by randomization with 80 patients in each group:

GROUP D: received 0.5 µg/kg of DEX diluted with normal saline to a volume of 20 cc.

GROUP C: received 20 cc of normal saline.

Duration and severity of shivering, hemodynamic changes (heart rate and blood pressure), changes in body temperature, sedation rate, and side effects (nausea and vomiting) were evaluated and recorded before and after spinal anesthesia, during umbilical cord clamping, and then every 5 min until 45 min after drug administration. The duration of spinal anaesthesia and surgery were also recorded. The end of spinal anaesthesia was when patients could move their legs.

In the case of hypotension of more than 20% of baseline or blood pressure less than 90 mmHg, 50 mcg phenylephrine was injected intravenously. Furthermore, a decrease in heart rate (HR < 60 beats/min) was treated with 0.5 mg intravenous atropine. The incidence of nausea and vomiting was also recorded and managed under the supervision of an anaesthesiologist.

The level of shivering was measured based on the Chu and Tsai score in four grades as follows: (1) grade 0: no shivering; (2) grade 1: piloerection and peripheral vasoconstriction without obvious shivering; (3) grade 2: muscle activity (frequent contractions) in only one muscle group; (4) grade 3: muscle activity in more than one muscle group but not generalized; (5) grade 4: shivering all over the body. If the patient had ≥ grade 3 continuous shivering for 15 min, 0.5 mg/kg meperidine was used to control the shivering. Sedation score was evaluated and recorded in 5 levels based on: (1) the Ramsey sedation scale: 1; (2) fully awake and alert: 2; (3) sleepy: 3; (4) the patient closes her eyes and wakes up with a command: 4; (5) the eyes are closed, and the patient wakes up with physical stimulation: 5. The eyes are closed, and the patient does not wake up with physical stimulation.

In our A total of 160 women with a mean age of 26.61 ± 5.7 years (18 - 35 years) participated in the study. The results related to the basic characteristics of patients and the duration of spinal anesthesia and surgery are presented in Table 1. As could be observed, the two groups were not significantly different in terms of age, height, weight, body mass index, duration of spinal anesthesia, duration of surgery, and spinal interval to the start of surgery (P < 0.05).

TABLE 1 showing demographic and clinicaldistribution of patients in 2 groups

The hemodynamic changes at different times in groups D and C are presented in Table 2. As observed, heart rate was not significantly different between the two groups in none of the studied times (P < 0.05). Mean systolic blood pressure on minutes 5, 10, 15, 20, and 30 was significantly different between the two groups so that at the mentioned times, it was higher in group D than in group C. However, no significant difference was observed between the two groups at other times. Furthermore, diastolic blood pressure was significantly higher in group D on minutes 5 and 10 than in group C, but there was no significant difference between the two groups at other times.

TABLE 2 Comparison of Hemodynamic Parameters at Different Times Between the Two Groups

TABLE 3 showing quality of block in 2 groups.

The changes in body temperature and shivering score at different times are presented in Table 3. As shown in Table 3, body temperature at the time of umbilical cord clamping showed a significant difference between the two groups (P = 0.035). No significant difference was observed between the two groups at other times (P < 0.05). In addition, the mean score of shivering on minutes 20, 30, and 45 in group D was significantly lower than group C (P = 0.022, P = 0.029, and P < 0.0001, respectively). No significant difference was found between the two groups at other times (P < 0.05). In group D, the shivering score did not significantly differ between different times (P < 0.05).

The results of this study showed that the frequency of tremor was statistically higher in group C compared to group D. The patient was found to have tremor (paragraph 3). In group D patients, tremors appeared at 30 minutes and disappeared at 45 minutes. In group D, a significant decrease in tremor scores was observed at 20, 30 and 45 minutes. In this study, there was no difference in body temperature between the two groups except when the umbilical cord was clamped. Yu et al. reported that in women undergoing cesarean section due to shivering due to spinal cord injury, all patients responded to 0.5 µg/kg DEX within 15 minutes (15). The results showed that infusion of DEX (30 µg) reduced the duration of shivering in women undergoing spinal surgery and epidural anesthesia compared with placebo (17.9 minutes vs. 2.6 minutes). Fifteen minutes after administration, 90% of patients in the DEX group were free of shivering, compared with 22.5% in the control group (19). Nasseri et al evaluated the effect of DEX (5 µg intrathecally) in women undergoing spinal surgery. The results showed that there was no difference in body temperature (body temperature and forehead) between the DEX and saline groups during and after surgery. However, the incidence of shivering was higher in the saline group than in the DEX group (52% vs. 24%). In addition, according to the study by Chu and Tsai, tremors were significantly higher in the control group than in the DEX group (20). In another study by He et al. The results showed that intrathecal administration of 5 µg DEX reduced the incidence and severity of tremors compared with the control (36.5% vs. 6.7%, P = 0.005). In contrast, 2.5 µg DEX did not reduce tremors in women undergoing spinal surgery compared with controls. However, pain intensity decreased in both DEX groups compared to controls (21). Botros et al. have shown that prophylactic administration of DEX (1 µg/kg) is effective in reducing the incidence and severity of tremors after spinal cord injury compared to placebo (7). and excessive sedation that may occur after bolus injection (< 2 min). However, these changes reverse over time (15,22,23). In this study, DEX was injected continuously for 10 min. We found that DEX infusion at the time of umbilical cord clamping during cesarean section was associated with lower hemodynamic instability compared with placebo. Both groups showed a decrease in systolic blood pressure after SCI, but it increased rapidly when the umbilical cord was clamped in group D. Other times are different. (15) Clinical studies by He et al. The results showed that mean arterial pressure and heart rate did not differ between the two groups at different times after spinal surgery (21). Prabhakaran et al. reported that there was no significant difference in the incidence of bradycardia and hypotension between the DEX group and the saline group after spinal cord injury (24).

The results of this study showed that the mean sedation score was higher in the DEX group than in the control group at 10, 15 and 20 minutes (30). Nasseri et al. (20) showed that the degree of sedation was significantly higher in the DEX group than in the control group. In another study, Botros et al. Studies have shown that postanesthetic prophylactic administration of DEX (1 µg/kg) in patients undergoing lower extremity surgery provides significant sedation compared with placebo (7). DEX is a selective α2-adrenoceptor agonist with central nervous system, sedative, and analgesic effects (23, 25, 26). There was no significant difference (nausea and vomiting) between groups D and C (11 vs. 13). Nasseri et al. (20) and He et al. (21) showed that the incidence of side effects (such as nausea, vomiting, bradycardia) after DEX in women undergoing spinal cesarean section was not significantly different from placebo. Some differences between our study and previous studies may be due to subject and methodological characteristics. The current study has limitations such as small sample size and not measuring body temperature. Therefore, multi-site studies with larger samples are recommended to obtain more accurate results.

The results of the present study suggested that the intravenous administration of DEX could effectively reduce the incidence and severity of shivering in patients undergoing C-sections, creating a higher sedation level and more hemodynamic stability without significant complications. Consequently, intravenous DEX could be used as an effective and safe medicine in preventing shivering and reducing patient discomfort in women undergoing C-sections.

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