Dehydration and Postoperative Complications

April 21, 2015

Intraoperative and postoperative dehydration are risk factors for DVT, as are patient factors (cancer, advancing age, previous VTE, obesity, varicose veins, and estrogen use), general anaesthesia (versus spinal/ epidural anaesthesia) and surgical factors (infection, immobilization, prolonged surgery and inpatient surgery) as identified in  .

Dehydration, as well as over-hydration, likely also correlates with other impaired postop outcomes, including renal impairment, increased infections, pulmonary oedema, cardiac complications and coagulopathy. Ideally we would monitor continuously all patients’ hydration status before, during and after operations, and employ Goal Directed Therapy/ GDT in moderate and high risk patients. See

Non-invasive ways (similar to saturation probes) to determine degree of hydration have been validated against gold-standard invasive methods (those requiring arterial and central lines) for more than 10 years. These permit targeted fluid therapy (i.e. use of GDT). In an ideal world this would be performed throughout the perioperative period for most moderate and all high risk patients.

Methods include:

  1. Clinical:
    1. Postural hypotension if the patient is >10% dehydrated (in the absence of other autonomic disease)
    2. Straight-leg raise test: if this increases BP, the patient is >10% dehydrated
  2. Sensmart
  3. Edwards Lifesciences NexFin/ ClearSight
  4. Cheetah NICOM

Optimising hydration status – to specific end-points – becomes more important with increasing patient and surgical complexity. Simple measures, such as minimising fasting times, will also assist.

Perioperative Solutions assists with workflow optimisation to integrate cross-functional requirements and so improve perioperative outcomes. See Perioperative for more information.

Posted in Artior Somnus, Blog by Douglas Fahlbusch