Written By:

Matthew Celik, MS, RD, LD, CNSC, Brooke Doucet, RN, BSN, CBN, Eva Panigrahi, PhD

A reduction in hospital readmissions is associated with decreased Medicare spending and improved patient outcomes. In metabolic and bariatric surgery (MBS), key quality metrics such as emergency department (ED) visits, hospital readmissions, and reoperations significantly influence healthcare costs, patient satisfaction, and post-operative quality of life. High rates of these adverse events can negatively impact a MBS center’s accreditation, funding, and reimbursement eligibility¹.

Prior studies indicate that within 90 days postoperatively, nausea, vomiting, and dehydration are the most frequent reasons for emergency department visits, readmissions, or reoperations. These symptoms likely lead to reduced oral intake, thereby increasing susceptibility to dehydration ^2,3,4,5.  According to the 2024 MBAQIP 30-day outcome report, 4.1% of patients required outpatient IV fluid therapy. Additionally, among the 9% of patients who presented to the Emergency Department post-operatively, 14.7% reported constipation and 3.3% experienced oral intake intolerance, both of which are clinical indicators commonly associated with dehydration. These findings underscore the importance of recognizing and addressing hydration related complications in the bariatric population.

Post-MBS readmission rates differ across the literature, yet several studies report rates reaching 20-30%, nearly half of which may be preventable¹. In response, many hospitals and bariatric clinics have implemented strategies to reduce preventable ED visits and readmissions—such as enhanced discharge instructions, frequent post-operative follow-up, and outpatient rehydration options.

The adult human body is composed of approximately 60% water, though this can vary between 45% and 75% depending on age, sex, and body composition ⁶ . This makes water the most abundant component in our bodies, playing a vital role in nearly every physiological function.

Key Roles of water in the body include:

• Regulating body temperature, heart rate and blood pressure ⁷
• Cushioning and lubricating joints through synovial fluid ⁷
• Protecting the spinal cord and other sensitive tissues via cerebrospinal fluid ⁷
• Eliminating waste through urination, perspiration and bowel movements ⁸
• Supporting metabolic processes and acting as a medium for biochemical reactions, i.e. transporting nutrients and waste, breaking down carbohydrates, fats and proteins ⁷

Water is not only crucial for weight loss and maintenance, but also for maintaining the health of the entire body- including the joints, bowels, heart and spine. Without water, survival is impossible. And without adequate hydration, the body’s ability to function and perform begins to decline ⁹.

Recognizing the Signs and Symptoms of Dehydration

Mild to Moderate Dehydration

• Dry mouth or lips
• Thirst
• Dark yellow urine or reduced output
• Fatigue or tiredness
• Dizziness or lightheadedness
• Headache
• Cool or dry skin
• Muscle cramps
  
  

Severe Dehydration (Medical Emergency)

• Little to no urine output
• Rapid heartbeat or breathing
• Sunken eyes
• Confusion or irritability
• Fainting
• Low blood pressure
• Cold, clammy skin

Prevention Starts Pre-Op: Education and Expectation Setting

Ideally, hydration education should begin during the pre-operative phase, when patients are learning how to prepare for surgery and life afterward. Many programs establish pre-surgery fluid intake goals to help set expectations for, and give patients a chance to practice, important post-surgery habits.

During this phase, patients should interact regularly with the multidisciplinary care team, including Nurse Practitioners (NPs), Registered Nurses (RNs), Registered Dietitians (RDs), and behavioral health providers (i.e., psychologists, social workers, licensed counselors, etc.). Behavioral health providers can reframe hydration as an act of self-regulation and self-care, not just a post-op requirement. Hydration, when integrated mindfully, supports mood, memory, and metabolic health. Each discipline plays a role in preparing patients for adequate fluid intake and preventing dehydration.

Multidisciplinary Roles in Dehydration Prevention

Physician/Advanced Practice Providers

• Outline pre- and post-op fluid intake goals
• Provide regular follow-up and monitor hydration status during routine postoperative visits
• Screen patients for outpatient IV fluid infusion
• Review laboratory testing results for indications of dehydration-related issues
  
  

Registered Nurses

• Perform comprehensive hydration assessments during inpatient recovery and perioperative visits, integrating vital signs, weight trends, and clinical presentation
• Analyze hydration-related data to identify early signs of dehydration, fluid overload, or electrolyte imbalance
• Educate patients on hydration strategies, signs and symptoms of dehydration, and postoperative fluid needs
• Assess environmental, behavioral, and clinical factors affecting hydration status (e.g., nausea, mobility, access to fluids, comorbidities)
• Communicate findings and concerns to the care team and escalate abnormailities per clinical protocols
• Support care planning and interventions related to fluid management in collaboration with providers

Registered Dietitians

• Educate on fluid goals during pre-op visits and determine readiness for surgery
• Educate patient on risk of dehydration post-op
• Provide education regarding fluid intake and necessary post-operative eating and drinking behaviors
• Monitor and document fluid intake
• Counsel patients regularly after surgery and assess adherence and adjust plan as needed

Behavioral Health

• Reinforce expectations about necessary post-operative behavior changes
• Address mental health and behavioral barriers to adequate hydration
  • Motivation Interviewing and Cognitive Behavioral Therapy (CBT), including psychoeducation, cognitive reframing, behavioral problem-solving may be helpful with addressing resistance and/or barriers

Physical Therapy/Exercise Specialists

• Monitor for signs/symptoms of dehydration
• Assess and encourage fluid intake before, during, and after physical activity sessions

Fluid Intake Guidelines and Strategies

To maintain hydration and prevent dehydration, post-MBS patients are typically advised to consume 1.5–2 liters (48–64 oz) of fluid daily. Due to the reduced gastric volume post-surgery, patients should sip fluids slowly and continuously throughout the day—not gulp or chug.

Because changing long-standing habits can be difficult, patients are encouraged to practice sipping pre-operatively and implement the following strategies:

• Keep recommended fluids on hand at all times; sip between meals, not during
• Use a 1 oz medicine cup or sipping water bottle to regulate intake
• Consider using hydration reminder apps or bariatric-specific mobile apps to support consistent fluid intake goals
• Track intake with self-monitoring tools
• Set hydration-related daily benchmarks (e.g., drink 32 oz by lunch, another 32 oz by bedtime)
• Use flavored fluids like infused water, zero-sugar beverages, or popsicles to prevent taste fatigue
• Carry a thermos or bottle of water at all times

In summary, hydration is a cornerstone of recovery and long-term success after MBS. Because the stomach’s capacity is significantly reduced, patient must be intentional about fluid intake to prevent dehydration. By prioritizing hydration, patients support not only their weight loss outcomes but also their overall health.

References:

1. Ivanics, T., Nasser, H., Leonard-Murali, S., & Genaw, J. (2019). Dehydration risk factors and impact after bariatric surgery: An analysis using a national database. Surgery for Obesity and Related Diseases, 15(12), 2066–2074. https://doi.org/10.1016/j.soard.2019.09.054
2. Kellogg, T. A., Swan, T., Leslie, D. A., Buchwald, H., & Ikramuddin, S. (2009). Patterns of readmission and reoperation within 90 days after Roux-en-Y gastric bypass. Surgery for Obesity and Related Diseases, 5(4), 416–423. https://doi.org/10.1016/j.soard.2009.01.008
3. Major, P., Wysocki, M., Torbicz, G., Gajewska, N., Dudek, A., Małczak, P., Pędziwiatr, M., Pisarska, M., Radkowiak, D., & Budzyński, A. (2018). Risk Factors for Prolonged Length of Hospital Stay and Readmissions After Laparoscopic Sleeve Gastrectomy and Laparoscopic Roux-en-Y Gastric Bypass. Obesity Surgery, 28(2), 323–332. https://doi.org/10.1007/s11695-017-2844-x
4. Preventing Returns to the Emergency Department FollowingBariatric Surgery | Obesity Surgery. (n.d.). Retrieved July 22, 2025, from https://link.springer.com/article/10.1007/s11695-017-2624-7
5. Rashdan, M., Al-Sabe, L., Salameh, M., Halaseh, S., Al-Mikhi, B., Sha’bin, S., Alqirem, L., Alsaadi, T., Ahmad, J., Sabbagh, A., Haddad, F., Algharrawi, Y., Alghazawi, L., & Nofal, M. N. (2024). Predictive factors for readmission after bariatric surgery: Experience of an obesity center. Medicine, 103(32), e39242. https://doi.org/10.1097/MD.0000000000039242
6. Cherney, K. (2022, October 14). What percentage of the human body is water? Medical News Today. https://www.medicalnewstoday.com/articles/what-percentage-of-the-human-body-is-water
7. Biology Insights. (2025, July 24). Functions and importance of human water in the body. https://biologyinsights.com/functions-and-importance-of-human-water-in-the-body/
8. Mayo Clinic Health System. (2022, September 29). Water: Essential for your body. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/water-essential-to-your-body-video
9. The Science Desk. (2025, July 28). The importance of hydration for overall wellness: Your complete guide. Science News Today. https://www.sciencenewstoday.org/the-importance-of-hydration-for-overall-wellness-your-complete-guide

TREO Foundation thanks all who contributed to this article.