From the Guidelines
Total spinal anesthesia can cause severe central nervous system symptoms, including respiratory depression, hypotension, bradycardia, and even cardiac arrest, emphasizing the need for immediate intervention with airway protection, ventilatory support, and circulatory management 1. The complication of anesthesia ascending the spinal cord and causing central symptoms is called "high spinal" or "total spinal anesthesia." This occurs when spinal anesthetic medication spreads higher than intended, affecting upper thoracic and cervical levels of the spinal cord.
Key Symptoms and Management
- Hypotension and bradycardia occur first due to sympathetic blockade
- Respiratory difficulty as intercostal and diaphragmatic nerves become affected
- Loss of consciousness and cardiovascular collapse if the medication reaches brainstem levels Management includes:
- Immediate airway protection
- Ventilatory support with intubation if necessary
- Aggressive fluid resuscitation
- Vasopressors for hypotension
- Atropine for severe bradycardia As reported by 1, the risk of high- or total-spinal anaesthesia is increased when spinal anaesthesia is attempted following a failed epidural top-up, and the incidence during spinal anaesthesia has been estimated to be approximately 1 in 4367 cases.
Prevention and Vigilance
Preventing total spinal anesthesia involves careful dosing and monitoring, with the block height assessed at least once every 5 min until no further extension is observed 1. Increasing agitation, significant hypotension, bradycardia, upper limb weakness, dyspnoea, or difficulty in speaking may indicate the need for intervention. Given the potential for severe complications, prompt recognition and intervention are crucial to prevent serious consequences, including cardiac arrest, in patients experiencing total spinal anesthesia 1.
From the Research
Central Nervous System Symptoms
- Central nervous system signs such as excitation, convulsions, followed by loss of consciousness and respiratory arrest can occur due to total spinal anesthesia causing systemic toxicity of local anesthetics 2
- Seizures are the most common presentation of local anesthetic systemic toxicity, and benzodiazepines are recommended to treat convulsions 2, 3
- The spectrum of presenting neurologic symptoms and signs are broad and can be obscured by perioperative processes 3
Prevention and Treatment
- Prevention remains the criterion standard for improving patient safety during regional anesthesia, and preparing a plan of action ahead of time and having the necessary tools readily at hand will contribute to saving the patient's life 4
- Airway management, oxygenation, ventilation, and good basic life support are the sine qua non of successful resuscitation 4
- Lipid emulsion therapy should be given at the first sign of serious systemic toxicity with an initial bolus dose of 100 ml for adults weighing greater than 70 kg and 1.5 ml/kg for adults weighing less than 70 kg or for children 5, 3
Risk Factors and Incidence
- The incidence of local anesthetic systemic toxicity is 1-11 cases per 10,000 2
- Infants, patients with decreased liver function and low cardiac output are vulnerable to systemic toxicity 2
- Predisposing factors of local anesthetic systemic toxicity include extremes of age, pregnancy, renal disease, cardiac disease, hepatic dysfunction, and drug-associated factors 5