High or total spinal
Why examiners ask this
A high spinal is the commonest serious complication of neuraxial anesthesia on a labor floor, and it usually appears as the moment after a routine top-up when the patient says she cannot breathe. The examiner tests recognition, organization under pressure, and judgment about when to intubate. The follow-up questions probe prevention: the unrecognized intrathecal catheter, the spinal after a failed epidural, and the test dose.
The 60-second answer
A patient who develops upper-extremity weakness, dyspnea, difficulty speaking, hypotension and bradycardia after a neuraxial dose has a high block until proven otherwise. I stop any infusion, call for help, put her supine with left uterine displacement, and support the airway with 100% oxygen; rapid airway control is essential and reverse Trendelenburg does not limit spread.1 I treat hypotension and bradycardia aggressively: phenylephrine, ephedrine, and epinephrine early if she is profoundly hypotensive, with atropine or glycopyrrolate for bradycardia. If she cannot phonate, cannot protect her airway, or loses consciousness, I intubate with a rapid sequence induction. I monitor the fetal heart rate and, if the mother is in arrest, start ACLS and plan perimortem delivery at 4 minutes.2 Recovery is expected; she needs sedation and ventilation until the block recedes.
Decision points and the "why"
- Treat the cardiovascular collapse first — cardiac accelerator fibers (T1–T4) are blocked, so bradycardia and loss of venous return combine. Phenylephrine alone is insufficient with bradycardia; I go to ephedrine and then epinephrine 10–100 mcg in titrated doses.
- Intubate on function, not on level — the threshold is inability to speak, inadequate ventilation, aspiration risk with a full stomach, or loss of consciousness. A high sensory level with good phonation and saturation is managed with support and reassurance.
- Induction drug — she is sympathectomized, so I use a small dose of etomidate or ketamine, or none if she is unconscious, with succinylcholine or rocuronium.
- Unconsciousness and apnea — they reflect brainstem hypoperfusion as much as direct anesthetic effect; restoring blood pressure often restores breathing.
- Uterine displacement and fetus — aortocaval compression makes everything worse; the fetal heart rate reflects maternal perfusion.
- Prevention — incremental epidural dosing, aspiration and test dosing of every catheter, and caution with a spinal after a failed or partially working epidural, where I reduce the spinal dose.
The complication they will inject
After a 10 mL bolus of 0.25% bupivacaine through a labor catheter, she becomes apneic and pulseless. I declare a maternal cardiac arrest, start compressions with manual left uterine displacement, call the obstetric and neonatal teams, and give epinephrine 1 mg IV at standard nonpregnant doses. I intubate and ventilate with 100% oxygen at about 10 breaths per minute; with a high block, respiratory arrest may precede the arrhythmia.2 I consider local anesthetic systemic toxicity as well as a total spinal, because the same dose in a vein gives arrest too, and I give 20% lipid emulsion 1.5 mL/kg then 0.25 mL/kg/min if there is any doubt.2 If spontaneous circulation does not return by 4 minutes, I tell the obstetrician to begin resuscitative hysterotomy at the bedside so delivery happens by 5 minutes.2 After return of circulation, I keep her sedated and ventilated, investigate the catheter position, and disclose to the patient.
Pitfalls that cost points
- Treating the blood pressure with phenylephrine alone while the heart rate falls to 40.
- Intubating reflexively because the level is high, without assessing function.
- Forgetting left uterine displacement and the fetal heart rate.
- Failing to mention the unrecognized intrathecal or subdural catheter as the cause.
- Omitting the 4-minute rule for perimortem delivery when arrest occurs.
Rapid-why
Q: Why does a spinal after a failed epidural risk a high block? A: Epidural volume compresses the dural sac and drug can cross the hole, so intrathecal drug spreads further than expected.
Q: How does a subdural block differ? A: It is slow (15–30 minutes), patchy, high and sensory-dominant with relative sparing of sympathetic and motor fibers.
Q: Why give epinephrine early? A: It provides chronotropy, inotropy and vasoconstriction together; the mechanism is profound sympathectomy, and small doses reverse it.
Q: Why does the patient stop breathing with a cervical block? A: The phrenic nerve (C3–C5) is blocked, and brainstem hypoperfusion depresses the respiratory center.
Numbers to know
| Item | Value |
|---|---|
| Cardiac accelerator fibers | T1–T4 |
| Phrenic nerve | C3–C5 |
| Epinephrine for collapse | 10–100 mcg IV titrated; 1 mg in arrest |
| Perimortem delivery | Incision at 4 min, delivery by 5 min2 |
| Uterine displacement | Manual left displacement preferred; 30° tilt impairs compressions2 |
Links
- Spinal anesthesia: dosing, spread, hypotension, Epidural anesthesia and the test dose, Maternal cardiac arrest and resuscitative hysterotomy (coming), Local anesthetic systemic toxicity, ACLS adapted to the operating room
- ASA Practice Guidelines for Obstetric Anesthesia; SOAP consensus statement on the management of cardiac arrest in pregnancy
Sources
- 1.Obstetric Regional Anesthesia · NYSORA · nysora.com
- 2.SOAP Consensus Statement on the Management of Cardiac Arrest in Pregnancy · SOAP (Lipman et al., Anesth Analg), 2014 · soap.org
Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.