Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Journal of Obstrectic Anaesthesia and Critical Care
Search articles
Home Print this page Email this page Small font size Default font size Increase font size Users Online: 208

 Table of Contents  
Year : 2021  |  Volume : 11  |  Issue : 1  |  Page : 46-47

Subdural injection: A possible cause of loss of consciousness during cesarean section

Department of Anesthesia, Makassed General Hospital, Beirut, Lebanon

Date of Submission08-Sep-2020
Date of Acceptance12-Dec-2020
Date of Web Publication16-Apr-2021

Correspondence Address:
Dr. Zoher Naja
Makassed General Hospital, Beirut
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/joacc.JOACC_97_20

Rights and Permissions

Spinal anesthesia is commonly used for cesarean section as it is safe and effective. However, subdural block can occur which might lead to loss of consciousness. We hereby report a parturient who received epidural analgesia for normal vaginal delivery followed by spinal anesthesia for emergency cesarean section and lost consciousness for 5 min after 10 min of spinal anesthesia induction.

Keywords: Epidural analgesia, loss of consciousness, spinal anesthesia, subdural block

How to cite this article:
Barada MA, Kanawati S, Rajab O, Naja Z. Subdural injection: A possible cause of loss of consciousness during cesarean section. J Obstet Anaesth Crit Care 2021;11:46-7

How to cite this URL:
Barada MA, Kanawati S, Rajab O, Naja Z. Subdural injection: A possible cause of loss of consciousness during cesarean section. J Obstet Anaesth Crit Care [serial online] 2021 [cited 2021 Jun 15];11:46-7. Available from: https://www.joacc.com/text.asp?2021/11/1/46/313916

  Introduction Top

Epidural analgesia is used for pain management during normal vaginal delivery (NVD).[1] Many patients require emergency cesarean section due to signs of fetal distress or lack of progress.[2] Spinal anesthesia is commonly used for cesarean section as it is safe and effective.[3] However, subdural block can occur which might lead to loss of consciousness.[3] We hereby report a parturient who received epidural analgesia for NVD followed by spinal anesthesia for emergency cesarean section and lost consciousness for about 5 min after induction of spinal anesthesia.

  Case Report Top

A healthy 32-year-old woman was 36 weeks pregnant with her first baby. The obstetrician requested an epidural catheter to be placed early before induction of labor. An epidural catheter had been administered in the labor process and the patient was off pain during the whole period except for the last 1 h when the patient started feeling pain with a visual analog scale (VAS) score of 5/10. The agents used for epidural were 0.1% bupivacaine, fentanyl 2 μg/mL, and clonidine 75 μg. These agents were given first as 10 mL bolus over 3 min, then as an infusion through an automatic infusion pump with a rate ranging from 8 mL/h to 16 mL/h according to the stage of labor and patient's pain. After approximately 8 h a decision was made by the attending obstetrician to perform an acute cesarean section owing to failure of progress. The obstetrician assessed the section to be grade 3 (needing early delivery but no maternal or fetal compromise).

After arriving in the operating room, the patient was put on monitor and vitals were taken showing a baseline saturation of 100%, blood pressure 120/70, and heart rate 90 beats/min. The anesthesiologist administered a mixture bolus of 8 mL xylocaine 2% and 7 mL marcaine 0.5%. A cold desensitization test was done and showed desensitization up to level T10. Taking into consideration the need for a higher level of anesthesia for a cesarean section, the decision was made to remove the epidural catheter and perform spinal anesthesia at the L4-L5 intervertebral space.

In a sitting position, a dose of hyperbaric marcaine 0.5% 10 mg and sufentanil 5 μg were administrated intrathecally according to local routines. The patient was then immediately held in the supine position. After 10 min of administration, the patient suddenly stopped communicating. She was not responding to verbal commands or deep pain. The incident was not preceded by nausea and vomiting. There were no complaints of chest pain, inability to breathe, or weakness of the upper limbs immediately before loss of consciousness. No tonic clonic movements were suggesting epileptic activity. There was a period of apnea with a dramatic drop in oxygen saturation to around 75%. The patient's lungs were ventilated with a bag and mask ventilation on the circle system, and saturation gradually increased back to baseline. No bronchospasm, urticaria, hypotension, or bradycardia were noted. Within 5 min, the mother could open her eyes, later flex the fingers of both hands, accomplish voluntary breathing on request, and responded to deep pain. The patient was hemodynamically stable throughout the whole period with a blood pressure of 110/70 and a heart rate of 100 beats/min. Facemask was applied with an oxygen flow of 5 L/min and the patient was spontaneously breathing. A healthy male baby was delivered immediately with an Apgar score of 9 at 1 min and 10 at 5 min. About 45 min after the end of the surgery, the facemask was removed, the patient had a saturation of 99% on room air and was fully awake conscious cooperative, and oriented. The rest of the postoperative period was uneventful.

  Discussion Top

An accidental subdural block following spinal anesthesia or epidural analgesia has been reported.[1],[4],[5],[6],[7] Some of the known complications of subdural injection include delayed onset of the block, extensive sensory blockade with minimal motor block, and hypotension.[7] Another possible complication is loss of consciousness.[3],[4],[8]

Loss of consciousness was reported in patients after spinal anesthesia for cesarean section although with hemodynamic and cardiovascular stability.[3],[4],[9] This is similar to our case wherein the patient did not experience chest pain, difficulty in breathing, or weakness of the limbs before the loss of consciousness. The subdural block is usually expected to start about 15 to 20 min post injection. Nevertheless, loss of consciousness and apnea can occur in a short time after administering anesthesia since the subdural space is limited.[4] Patients described by Chan et al. and Bhati et al. had a loss of consciousness lasting about 60 and 30 min after 20 and 12 min of spinal anesthesia injection, respectively.[3],[9] The patient in the present report experienced loss of consciousness for 5 min, which started 10 min after spinal anesthesia induction. However, the patient reported by Kayaalti et al. had three episodes of loss of consciousness. The first episode occurred 10 min after spinal anesthesia and lasted for 5 min. The second and third episodes lasted for 5 and 3 min, respectively.[4]

Even though it is difficult to prove subdural injection in our case; yet, the progression of events indicated the possibility of subdural injection of the anesthetic. The progressive and gradual return of function suggests that it could have been associated with an anesthetic block that diminished with time.[9] Subdural injection leads to the cephalic spread of a local anesthetic agent into the cranial cavity. During the insertion of the spinal needle into the subarachnoid space, the bevel might lie within the subarachnoid and subdural spaces. The free flow of cerebrospinal fluid at the time of aspiration might lead to the belief that the needle tip was fully placed in the subarachnoid space.[7]

This report demonstrated that accidental extensive subdural blockade could be rapid and might lead to a sudden loss of consciousness. Anesthesiologists should be aware of the possibility of this complication to ensure timely and effective management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Kalil A. Unintended subdural injection: A complication of epidural anesthesia--a case report. AANA J 2006;74:207-11.  Back to cited text no. 1
Virgin H, Oddby E, Jakobsson JG. Suspected total spinal in patient having emergent Caesarean section, a case report and literature review. Int J Surg Case Rep 2016;28:173-5.  Back to cited text no. 2
Bhati FS, Vijayvergia VK, Laxmi V, Sharma M. Loss of consciousness following spinal anaesthesia for caesarean section. Indian J Anaesth 2004;48:57-8.  Back to cited text no. 3
  [Full text]  
Kayaalti S. Intermittent loss of consciousness during cesarean section under spinal anesthesia: A case report. Braz J Anesthesiol 2019;69:631-4.  Back to cited text no. 4
Wills JH. Rapid onset of massive subdural anesthesia. Region Anesth Pain Med 2005;30:299-302.  Back to cited text no. 5
Singh B, Sharma P. Subdural block complicating spinal anesthesia? Anesth Analg 2002;94:1007-9.  Back to cited text no. 6
Bhardwaj M, Kiran S, Kaur K, Hooda S. Subdural block: A possible cause of transient aphasia following spinal anaesthesia. Sri Lankan J Anaesthesiol 2015;23:80-2.  Back to cited text no. 7
Karaca Ö, Ahıskalıoğlu A, Aksoy M, Doğan R, Oral AE. What happened? An inexplicable case: Accidental subdural block. Agri 2018;30:31-4.  Back to cited text no. 8
Chan YK, Gopinathan R, Rajendram R. Loss of consciousness following spinal anaesthesia for Caesarean section. Br JAnaesth 2000;85:474-6.  Back to cited text no. 9


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)  

  In this article
Case Report

 Article Access Statistics
    PDF Downloaded27    
    Comments [Add]    

Recommend this journal