Prevention and Management of Hypotension During Spinal Anesthesia: A Narrative Review
Review Summary
A narrative review examining the causes, risk factors, clinical manifestations, prevention and management of hypotension associated with spinal anesthesia.
Spinal anesthesia is widely used in lower limb, lower abdominal and obstetric surgery because of its rapid onset, extensive sensory and motor blockade and good analgesic effect. Intraoperative hypotension is its most frequent complication and occurs through sympathetic vasomotor blockade, venous pooling, reduced venous return and compromised cardiac compensatory responses.
To present the causes, risk factors, manifestations and interventions that have been shown to prevent and treat hypotension following spinal anesthesia.
Articles were identified through searches of PubMed, Scopus and Google Scholar covering 2015 to 2026. Search terms included spinal anesthesia, hypotension, prevention, management, vasopressors, fluid therapy and hemodynamic monitoring. Eighty-seven records were retrieved and 45 articles were ultimately included in the narrative review.
Risk factors were grouped into patient-, procedure- and drug-related factors. Controlled crystalloid fluid co-loading and early vasopressor use, particularly phenylephrine or norepinephrine, were identified as important preventive strategies. Continuous non-invasive hemodynamic monitoring supports early identification and management of hemodynamic disturbances.
Spinal anesthesia-associated hypotension occurs primarily through sympathetic blockade. Recognition of relevant patient, procedural and drug-related factors, together with appropriate fluid management, early vasopressor use and hemodynamic monitoring, can support prevention and management.
Evidence Identification
The narrative review combined database searching with hand searching of reference lists to identify relevant literature on spinal anesthesia-induced hypotension.
PubMed, Scopus and Google Scholar were searched.
Records identified through the database search.
Articles remaining after title, abstract and full-text assessment.
Final literature base after adding 27 articles identified through hand searching.
How Hypotension Develops
Sympathetic blockade is the principal mechanism underlying hypotension following spinal anesthesia.
Sympathetic Blockade → Vasodilation → Reduced Venous Return
Blockade of sympathetic nerve fibres leads to arterial and venous vasodilation. Venous pooling reduces preload, while arteriolar dilation reduces systemic vascular resistance. The resulting reduction in stroke volume and cardiac output contributes to hypotension.
Sympathetic Blockade
Spinal anesthesia blocks sympathetic nerve fibres, reducing normal vasomotor tone.
Vasodilation
Arterial and venous dilation decreases systemic vascular resistance and increases venous capacitance.
Venous Pooling
Pooling in the lower extremities and splanchnic circulation reduces venous return and preload.
Reduced Cardiac Output
Reduced preload lowers stroke volume and cardiac output, producing a fall in arterial blood pressure.
Who Is at Greater Risk?
The review groups factors contributing to hypotension into patient-, procedure- and drug-related categories.
Patient Factors
- Pregnancy
- Advanced age
- Reduced intravascular volume
- Hypovolemia or dehydration
- Cardiovascular disease
- Hypertension
- Diabetes
- Reduced cardiovascular reserve
- Use of beta-blockers or antihypertensives
Technical Factors
- Higher spinal block level
- Local anesthetic dose
- Volume of local anesthetic
- Cephalic spread of the block
- Injection speed
- Patient positioning
- Aortocaval compression in pregnancy
Pharmacological Factors
- Type of local anesthetic
- Longer-acting local anesthetics
- Opioid adjuncts
- Clonidine
- Preoperative vasodilators
- Sedative medications
Early Identification Matters
Because hypotension can progress rapidly, early recognition supports timely fluid administration, vasopressor treatment and patient repositioning.
Signs & Symptoms
Possible manifestations include nausea, vomiting, dizziness, blurred vision, lightheadedness, fainting, cold or clammy skin, delayed capillary refill and bradycardia. Severe hypoperfusion may lead to restlessness, confusion or loss of consciousness.
Monitoring
The review describes frequent non-invasive blood pressure assessment following spinal anesthesia, ECG monitoring for bradycardia or arrhythmias, arterial blood pressure monitoring in high-risk patients and fetal heart-rate monitoring in obstetric practice.
A Multimodal Strategy
The review supports combining fluid management, vasopressor therapy, hemodynamic monitoring and appropriate positioning rather than relying on a single intervention.
Crystalloid Co-loading
Controlled crystalloid administration during spinal injection can support intravascular volume and reduce the impact of sympathetic vasodilation.
Early Pharmacological Support
Early vasopressor administration can restore vascular tone and maintain blood pressure more effectively than waiting for marked hypotension to develop.
Early Hemodynamic Recognition
Close blood pressure and cardiovascular monitoring allows hemodynamic disturbances to be recognised and treated promptly.
Optimise Venous Return
Leg elevation, lower-extremity compression and appropriate patient positioning may improve venous return as supportive measures.
Left Uterine Displacement
In pregnant patients, left uterine displacement can help reduce aortocaval compression and mitigate hypotension.
Patient-Specific Management
Fluid and pharmacological strategies should take account of baseline hydration, cardiovascular status, age and other patient-specific risks.
Pre-loading, Co-loading & Fluid Selection
The review discusses the timing, type and volume of intravenous fluid administration as important components of prevention.
Crystalloid Co-loading Is Favoured Over Crystalloid Pre-loading
Because crystalloids redistribute rapidly, administration during spinal injection can provide more useful intravascular expansion at the period when sympathetic blockade develops. Fluid therapy should nevertheless be individualised, particularly in older patients, patients with reduced cardiac reserve and patients at risk of fluid overload.
Commonly Used
Examples discussed include Ringer’s lactate, Hartmann’s solution and normal saline. They are readily available but redistribute relatively rapidly.
Longer Intravascular Persistence
Colloids remain within the circulation longer but are associated with important potential adverse effects, including anaphylaxis, coagulation disturbance and renal dysfunction.
Avoid One-Size-Fits-All Volume
Baseline hydration and cardiovascular status should guide fluid administration, with particularly careful management in older patients and those with reduced cardiac reserve.
Vasopressor Therapy
Vasopressors are central to restoring systemic vascular resistance and supporting cardiac output following spinal anesthesia-induced hypotension.
Established First-Line Option
The review identifies phenylephrine as a key vasopressor for spinal anesthesia-associated hypotension, particularly in obstetric anesthesia. Its alpha-1 vasoconstrictor effect restores vascular tone but may produce reflex bradycardia.
Increasingly Used
Norepinephrine combines alpha-1 vasoconstriction with mild beta-1 activity and may produce less bradycardia while supporting maternal cardiac output. The review notes that further evidence is required before considering it superior to phenylephrine.
Alternative Vasopressor
Ephedrine has mixed alpha- and beta-adrenergic activity and increases heart rate, myocardial contractility and peripheral vascular tone. It may remain suitable for selected patient groups.
Bradycardia Management
The review discusses atropine and glycopyrrolate in the management of bradycardia associated with severe sympathetic blockade.
Potential Adjunct
Ondansetron is discussed as a prophylactic adjunct that may reduce spinal anesthesia-associated bradycardia and hypotension through effects on the Bezold-Jarisch reflex.
Prevention Before Rescue
The review favours early or prophylactic vasopressor support over waiting until substantial blood-pressure reduction has already occurred.
Three Complementary Components
The review concludes that prevention and management are best approached through complementary interventions rather than a single therapeutic modality.
Fluid Co-loading
Support intravascular volume during the onset of sympathetic blockade.
Prophylactic Vasopressor
Maintain vascular tone and blood pressure before significant hypotension develops.
Optimal Positioning
Support venous return and reduce contributing mechanical factors such as aortocaval compression.
The review identifies sympathetic blockade as the central mechanism of hypotension and emphasises recognition of patient-, procedure- and drug-related risk factors, appropriate fluid management, early vasopressor use and hemodynamic monitoring.
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Narrative Review
A narrative synthesis of literature addressing the causes, risk factors, manifestations, prevention and management of hypotension during spinal anesthesia.
PubMed · Scopus · Google Scholar
The review searched literature using combinations of terms relating to spinal anesthesia, hypotension, prevention, management, vasopressors, fluid therapy and hemodynamic monitoring.
87 Records · 45 Included
Eighty-seven records were retrieved. Following screening and full-text assessment, 18 database articles were retained, with a further 27 articles identified through hand searching, giving 45 articles in the final review.
2015–2026
The methodology reports a literature search covering publications from 2015 to 2026.
Jahangir · Hashim · Khan · Ur Rehman · Ashraf
Anas Jahangir:
Conceptualisation, drafting, project administration and
revision.
Muhammad Hashim:
Methodology, literature search, screening and analysis.
Hira Khan:
Literature search, screening, drafting and revision.
Atia Ur Rehman:
Methodology, screening, analysis and supervision.
Fatima Ashraf:
Conceptualisation, methodology, analysis and editing.
Conflict of Interest & Funding
Conflict of Interest:
No conflict of interest.
Funding:
No funding received.
Editorial Timeline
CC BY 4.0
This article is published under the Creative Commons
Attribution 4.0 International licence.
DOI: 10.64573/torgj2606003
Volume 2 · Issue 3 · September 2026
The Operating Room Global Journal (TORGJ).
ISSN 3105-3262.
Narrative Review.
DOI: 10.64573/torgj2606003.
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