|CORRECTED AND REPUBLISHED
|Year : 2019 | Volume
| Issue : 2 | Page : 252-258
Shivering prevention during cesarean section by intrathecal injection of magnesium sulfate: randomized double-blind controlled study
|Date of Submission||26-Mar-2017|
|Date of Acceptance||25-Aug-2018|
|Date of Web Publication||12-Jun-2019|
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
. Shivering prevention during cesarean section by intrathecal injection of magnesium sulfate: randomized double-blind controlled study. Res Opin Anesth Intensive Care 2019;6:252-8
|How to cite this URL:|
. Shivering prevention during cesarean section by intrathecal injection of magnesium sulfate: randomized double-blind controlled study. Res Opin Anesth Intensive Care [serial online] 2019 [cited 2019 Oct 15];6:252-8. Available from: http://www.roaic.eg.net/text.asp?2019/6/2/252/260146
Correction to: Res Opin Anesth Intensive Care 2019,6:89-94; DOI: 10.4103/roaic.roaic_43_17
Post the publication, as there were multiple corrections that were missed earlier, the article is being corrected and republished.
Shivering prevention during cesarean section by intrathecal injection of magnesium sulfate: randomized double-blind controlled study
Mohamed F. Mostafa, Zein El-Abden Z. Hassan, Samia Moustafa Hassan
Department of Anesthesia and Intensive Care, Faculty of Medicine, Assiut University, Egypt
Correspondence to Mohamed F. Mostafa, MBBCh, MSc, MD, Assiut University Hospital, Department of Anesthesia, Assiut, Egypt.
Tel: +2 01001123062; fax: +2 088 2333327
Received 26 March 2017
Accepted 25 August 2018
Background Shivering was found to be a common side effect with spinal anesthesia. It was observed in about 55% of patients with neuraxial anesthesia. It results in increased oxygen consumption and pain, which usually interfere with patient’s monitoring.
Objectives This study was designed to show the effect of intrathecal injection of magnesium sulfate to control shivering during spinal anesthesia for cesarean section.
Study Design This study was a prospective randomized controlled double-blind study using a computer-generated randomization scheme.
Methods 84 Women were randomly allocated into 2 groups: Magnesium sulfate group (M); patients received intrathecal 2 ml of 0.5% heavy bupivacaine (10 mg) plus 25 mg MgSO4 (0.5 ml). Placebo group (P); patients received intrathecal 2 ml of 0.5% heavy bupivicaine (10 mg) plus 0.5 ml normal saline. Vital signs, temperature, shiverig score, sensory level, motor block, and any complications were recorded.
Results Shivering score revealed a statistically significant difference between both study groups throughout the whole intraoperative and postoperative periods with lower shivering incidence in the M group. There was a statistically significant difference between both groups regarding temperature readings during the first 30 minutes postoperatively. Intraoperative sensory level block was statistically significantly different only 30 minutes after drugs injection. No serious complications were recorded in both groups.
Conclusion We concluded that intrathecal magnesium sulfate is safe and can decrease the incidence and intensity of shivering during cesarean section under spinal anesthesia, without having any serious side effects.
Keywords : shivering, cesarean section, magnesium sulfate
| Introduction|| |
Spinal anesthesia has many advantages when used for cesarean section. It is a popular technique with rapid onset and high success rate. Less maternal and fetal side effects are important advantages . However, shivering was found to be a common side effect with spinal anesthesia. It was observed in about 55% of patients with neuraxial anesthesia .
Shivering causes muscle contraction and increased body heat production as a protective mechanism. However, it results in increased oxygen consumption and pain, which usually interfere with patient’s monitoring .
Shivering is also associated with patient’s discomfort and dissatisfaction. Also, it may lead to many adverse postoperative outcomes as morbid cardiac events, increase surgical site bleeding and wound infection in women undergoing cesarean section .
The exact etiology of shivering is still unknown. The best way for shivering treatment after spinal anesthesia is unclear even after conduction of many studies ,. Thermo-sensory mechanisms in the human spinal canal was suggested by many studies to be responsible for decreasing the incidence of shivering after injection of warm anesthetic solutions intrathecally or epidurally .
For our knowledge, Few clinical studies examined the effect of intrathecal MgSO4 to prevent shivering after regional anesthesia. Intravenous infusion of MgSO4 has been demonstrated by many studies as an effective method for control of shivering after intrathecal anesthesia. Adding MgSO4 to anesthetic drugs has many benefits as improving intraoperative conditions and prolongation of analgesia. It decreases side effects as nausea or pruritis .
Many trials demonstrated the analgesic effects of magnesium sulfate in neuraxial block . It was reported that adding magnesium sulfate to bupivacaine prolonged the period of anesthesia without increasing the adverse effects . Other studies observed that the pain scores, rescue analgesics requirement were significantly lower after intrathecal magnesium sulfate injection . Addition of intrathecal magnesium sulfate (100 mg) to intrathecal morphine and local anesthetics in women undergoing caesarean delivery, improved quality and duration of postoperative analgesia without increasing the incidence of adverse effects .
This study was designed to show the effect of intrathecal injection of magnesium sulfate to control shivering during spinal anesthesia for cesarean section. Secondary outcomes included the temperature measurements, hemodynamic changes and any adverse effects.
| Methods|| |
After approval from the local ethics committee of faculty of medicine, Assiut University (ref. no. IRB00008718), written informed consents from women undergoing elective cesarean section were obtained. Clinical trials registration was approved under this number (NCT03008850). The study started on July 2015 and finished on December 2016.
Women’s Health Hospital, Assiut University.
Study Design and Randomization
This study was a prospective randomized double-blind controlled study using a computer-generated randomization program. It was carried out on 84 parturients scheduled for elective cesarean section under spinal anesthesia. Neither the investigator nor the participant was aware of the group allocation or the drug used. The study drugs used were prepared by one of the supervisor anesthesiologists (not included in the procedure, observation or in the data collection).
In order to detect a decrease in the incidence of shivering from 65% to about 40% using K2 test, we needed to include 84 patients in both groups with 0.05 as significant criteria and 95% power of the study. Patients were randomly allocated into two equal groups (each included 42 patients), group M (magnesium sulfate) and group P (normal saline) to compare between them regarding shivering control.
84 Women were randomly divided into two groups: Magnesium sulfate group (M); patients received intrathecal injection of 2 ml of 0.5% heavy bupivacaine (10 mg) plus 25 mg MgSO4 (0.5 ml). Placebo group (P); patients received intrathecal injection of 2 ml of 0.5% heavy bupivicaine (10 mg) plus normal saline (0.5 ml).
Age 18 to 45 years, ASA physical status I-II, scheduled for elective cesarean section under spinal anesthesia, singleton pregnancy, and at least 36 weeks of gestation.
Women with a history of cardiac, liver or kidney diseases. Women with history of allergy to amide local anesthetics or medication included in the study. Women with any neurological problem. Any contraindication of regional anesthesia. Failed or unsatisfactory spinal block. Preoperative temperature more than 38°C.
Operating room temperature was maintained at 24-26°C with a humidity of 55-60 % and no other warming devices were used. All intravenous fluids were warmed to the operative room temperature before infusion. All patients were covered intraoperatively by a single surgical drape and postoperatively by a single cotton blanket.
Standard preoperative data were collected prospectively for all patients undergoing elective cesarean section in our institution. All operations were carried out by one team of surgery and anesthesia was standardized in all patients. Assessment of the patient during preoperative period to form baseline data allowed to be compared with intraoperative and postoperative data. It consisted of three parts:
- Part I: Assessment of the sociodemographic patient’s profile: to assess patient’s name, age, type of surgery and ASA physical status.
- Part II: Assessment of maternal vital signs
- Part III: Laboratory investigations: Complete blood count (CBC), urea and creatinine level and coagulation profile.
While patient in the sitting position and under complete aseptic condition, we used 25-gauge needle in this study to decrease the incidence of post-dural puncture headache. Paramedian approach was used for intrathecal study drug administration at level of L3-4 or L4-5 intervertebral disc space of all patients.
- Vital signs: as non-invasive mean arterial blood pressure (MAP), heart rate (HR), oxygen saturation (SpO2), and respiratory rate (RR) were assessed every 5 minutes for the first 15 minutes and every 10 minutes thereafter until full recovery.
- Temperature measurements were performed using the tympanic probe before the spinal block, immediately after the spinal anesthesia and then every 30 minutes until 1 hour after entry into the PACU.
- Shivering was measured at the following time plans: immediately after spinal anesthesia, at 5, 10, 15, 20, 30, 40, 50, 60 and 90 minutes later. Shivering was graded where 0 = no visible shivering or muscular tonicity; 1 = mild increase in masseter or face muscle tonicity; 2 = tremor or muscular tonicity in proximal muscles; and 3 = tremor or muscular tonicity involving the whole body .
- Sensory level was assessed by the pinprick method (immediately after spinal then at 5, 10, 15 and 20 minutes intraoperatively and then at 30, 60, 90 and 120 minutes post operatively).
- Motor block was assessed using Bromage score  immediately after spinal then at 10, 15 and 20 minutes intraoperatively.
- Any complications related to the technique or the study drugs used were recorded and managed properly.
The collected data were coded, categorized, and tabulated using the appropriate statistical methods, SPSS version 20 (SPSS inc, Chicago, Illinois, USA). Parametric data were presented as mean ± standard deviation. Non-parametric data were presented as median (interquartile range), ratios and percentage as appropriate. P-value of less than 0.05 (P≤0.05) was considered significant.
Confidentiality and Ethical Consideration
All data taken from all participants in this research work either from history, examination or investigations were dealt with in a confidential manner. There was no serious complications affecting the women or their babies in the study.
| Results|| |
Eighty-four parturients were included in our study and were randomly assigned to two equal groups (of 42 parturients each). All parturients completed the study and no one was excluded due to any serious complications from the maneuver.
As regarding the demographic data and clinical characteristics (age, education, gestational age, number of previous spinal anesthesia, gravidity, and space used during injection), there was no statistically significant difference between both study groups ([Table 1]).
There was no statistically significant difference between the two study groups during the whole intraoperative and 2 hours postoperative periods regarding heart rate, mean arterial blood pressure, oxygen saturation or respiratory rate.
After 30 and 60 minutes postoperatively, the temperature readings were 37.1±0.3 in group P, 36.7±0.4 in group M and were 37.1±0.3 in group P, 36.8±0.5 in group M respectively. With a statistically significant difference between both study groups despite there was no definite hypothermia. There was no statistically significant difference as regarding temperature-monitoring readings throughout the rest of the 2 postoperative hours of observation ([Table 2]).
|Table 2 Comparison between the two study groups as regarding temperature changes|
Click here to view
As regards intraoperative sensory level, there was no statistically significant difference between both study groups from time of injection till 20 minutes after study drug injection but there was a statistically significant difference between both groups at 30 minutes after injection ([Table 3]).
Statistical analysis showed no statistically significant difference between both study groups as regarding the intraoperative motor blockade immediatly after intrathecal drugs injection. Both groups showed 100% motor block after 10 minutes of intrathecal drugs injection ([Table 4]).
Regarding the intraoperative shivering score, there was a statistically significant difference between both study groups throughout the whole intraoperative period (immediately after injection till 30 minutes after injection) with lower shivering incidence in the M group ([Table 5]).
Also, statistical analysis showed a statistically significant difference between both study groups throughout the whole postoperative period regarding shivering score with lower shivering incidence in the M group ([Table 6]).
There were no serious complications noted throughout the whole conduct of our study.
| Discussion|| |
Shivering is a common post-anesthetic complication. Prevention seems essential especially in vulnerable patients and should be effective. IV drugs are the “gold standard” for the treatment of postoperative shivering .
Magnesium sulfate (MgSO4) has a potential neuroprotective effect through enhanced neuroprotection against hypothermia adverse effects. It has also anti-shivering effects . Administration of intrathecal MgSO4 can provide effective perioperative analgesia. It prolongs the duration of anesthesia and potentiates the sensory blockade without increasing the adverse effects . Few clinical studies have examined the effect of adding intrathecal MgSO4 to the local anesthetic agents to suppress anesthesia-related shivering after spinal anesthesia. Therefore, we tried to investigate this effect in our study.
In our study, we added intrathecal magnesium sulfate to bupivacaine (group M) in cesarean section for evaluation of its effect in shivering prevention and compared it with placebo (group P). We reported a statistically significant difference between both study groups regarding the shivering score throughout the whole intraoperative period (immediately after injection till 30 minutes after injection) and 2 hours postoperatively; with lower shivering incidence in the magnesium sulfate group.
Our study recorded a statistically significant difference between both study groups as regarding body temperature despite there was no definite hypothermia.
In agreement with our results, some investigators concluded that intrathecal injection of magnesium sulfate improved perioperative shivering in female patients undergoing elective caesarean section. They used intrathecal 25 mg of magnesium sulfate plus the local anesthetic agent. Core temperature was measured before and after drug injection at predetermined intervals. Sedation was graded using the Ramsay sedation scale. They reported that core temperature was reduced in the intrathecal administered MgSO4 and a significant intergroup differences in appearance of shivering were seen only at 10, 15, and 20 min post block .
Gozdemir et al. concluded that MgSO4 infusion in the perioperative period significantly reduced shivering during transurethral resection of prostate with spinal anesthesia. MgSO4 infusion prevents shivering in patients receiving spinal anesthesia but increases the risk of hypothermia .
Not only magnesium sulfate that used as an effective drug in prevention of shivering but also many drugs were used to show their effect in shivering prevention. Another study showed that intrathecal bupivacaine combined with fentanyl is associated with a lower incidence and severity of shivering. They studied eighty healthy women (ASA Physical status I) undergoing elective cesarean section under spinal anesthesia .
Jain et al. evaluated the effect of intrathecal tramadol for prevention of shivering in anorectal surgeries under subarachnoid anesthesia and found that intrathecal tramadol is safe, reliable and cost effective adjuvant to spinal anesthesia . Ashraf et al. had a study, which showed that intrathecal naluphine is an effective and safe method to prevent shivering during spinal anesthesia in patients undergoing knee arthroscopy .
We did not found any significant difference related to the onset of sensory block, criteria of sensory or motor block between both groups. This is in agreement with another study reported that addition of intrathecal magnesium to spinal anesthesia to bupivacaine did not affect the time to reach the highest level of sensory block. They also concluded the addition of intrathecal MgSO4 (50 mg) to spinal anesthesia did not affect the time to complete recovery of motor function, but caused a signifcant delay in ambulation time .
Another investigators showed that the addition of magnesium sulfate to bupivacaine did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia .We reported no statistically significant difference between the two study groups throughout the study regarding the hemodynamics parameters. This is in agreement with Ghatak et al. study, where their groups were similar with respect to hemodynamic status .
In contrast to the intrathecal route, the intravenous administration of magnesium has also been used for management of eclampsia for many years. However, the problem is its poor passage across the blood-brain (spinal cord) barrier. If a large dose of magnesium is administered intravenously to increase its concentration in the brain, systemic hypotension and bradycardia will become prominent .
| Conclusion|| |
We concluded that intrathecal magnesium sulfate is safe and can decrease the incidence and intensity of shivering in women during cesarean section under spinal anesthesia, without having any serious side effects.
The study was conducted in a single center. Larger studies with larger sample size may be useful to confirm and validate our results. Different protocol designs may be needed in the future to investigate the different doses of intrathecal magnesium sulfate in affecting hypothermia or shivering incidence. We did not report correlation between body temperature and the incidence of shivering. Finally, we did not take in mind any other predisposing factors or pretreatments may affect the incidence of shivering after intrathecal anesthesia.
Financial support and sponsorship
The author participated in the design and conduct of the study, data analysis, writing and revision of the manuscript.
Conflicts of interest
There are no conflicts of interest.
Clinical Trials Registry Number: NCT03008850
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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