Postprandial hypotension 

Postprandial hypotension is a drop in blood pressure after eating. Spinal cord injury (SCI) significantly affects autonomic function, including disruption of baroreflex and cardiovascular regulation, increasing the risk of postprandial hypotension. It most commonly occurs in injuries at or above T6. 

Causes

The exact pathophysiology of postprandial hypotension remains unclear. It is caused by a combination of factors including:

• an imbalance between increased splanchnic blood flow after meals and the necessary adjustment of the cardiovascular system 
• impaired peripheral vasoconstrictor response 
• a lack of increase in heart rate, due to impaired sympathetic nervous system activation. 

Postprandial hypotension can be triggered within 15–120 minutes after ingesting a meal, although the most profound drop in blood pressure can occur approximately 60 minutes after the meal.

Compounding risk factors

Postprandial hypotension risk is increased with:

• increasing age 
• higher levels of SCI 
• completeness of SCI.

Other risk factors are associated with food intake, and include:

• timing — the risk is greatest after breakfast (compared with lunch and dinner) due to circadian changes in blood pressure  
• hotter meal temperatures 
• highly processed and/or high calorie foods, such as soft drinks, cordial, fruit juice, lollies and sweets
• the point in the digestive process where the stomach contents (acidic chyme) are transported to the duodenum 
• comorbidities, such as diabetes mellitus, and Parkinson’s Disease. 

Considerations for management

When managing episodes of postprandial hypotension, it is important to consider:  

• food temperature: colder food temperatures are less likely to trigger postprandial hypotension 
• high-fibre foods, which take longer to digest and may be less likely to lead to blood pressure drops after a meal. Common high-fibre foods include multigrain bread, rolled oats, wholemeal pasta, nuts, seeds, fruits and vegetables 
• that post-breakfast is when the risk of postprandial hypotension is highest 
• personal safety: if there have been episodes of postprandial hypotension, particularly at high-risk times (up to two hours after a meal) 
• other methods that can be utilised to assist with maintaining blood pressure, as outlined in orthostatic hypotension management. 

Liaise with a medical specialist in the Spinal Injuries Unit for consideration of medications for postprandial hypotension.