Electrolyte disorders in the surgical patient

New-onset hyponatraemia after surgery for traumatic hip fracture

BACKGROUND

hyponatraemia in orthopaedic patients is common but has been poorly investigated following surgery for traumatic hip fracture. The aims of this study were to define the incidence of new-onset post-operative hyponatraemia and to investigate associations between hyponatraemia and patient demographics, medication use and duration of hospital stay.

METHODS

all patients admitted to the Orthopaedic Unit for hip surgery following trauma in 2012 were retrospectively reviewed. Patients who developed post-operative hyponatraemia within 10 days of surgery were compared with patients who remained normonatraemic pre- and post-operatively.

RESULTS

a total of 254 patients were included. Overall, this study identified a significant (P =< 0.001) mean post-operative drop in serum sodium of 1.8 mmol/l (95% CI: 1.3-2.3%) compared with pre-operative levels. The incidence of moderate (<135 mmol/l) and severe (<130 mmol/l) post-operative hyponatraemia was 27% (95% CI: 21.7-32.5%) and 9% (95% CI: 5.7-12.8%), respectively. Statistical analysis revealed significant associations between the development of post-operative hyponatraemia and: (i) proton pump inhibitor use, (ii) selective serotonin re-uptake inhibitor use and (iii) increasing number of medications. Length of hospital stay was significantly increased in patients with moderate post-operative hyponatraemia compared with normonatraemic patients (30 versus 21 days; P =< 0.001). The incidence of new-onset post-operative hyponatraemia was not significantly increased by ethnicity, gender, fracture type, functional status or operative procedure.

CONCLUSION

hyponatraemia after surgery for hip fracture is common and results in longer hospital stay. This study provides evidence that an average post-operative drop in serum sodium concentration should be expected in this patient group. Moreover, patients taking SSRI or PPI medications may be at increased risk of post-operative hyponatraemia.

Postsurgical complications in older patients. The role of pharmacological intervention

The number of elderly patients undergoing surgery has been rapidly increasing during the last few years. Following surgical interventions, high rates of mortality and morbidity have been reported in the most advanced age groups. Nevertheless, perioperative evaluation and postoperative care are the major determinants of the overall outcome. Postsurgical complications are common in advanced age, since multiple pathology is often present in geriatric patients. Furthermore, the decreased efficiency of homeostatic mechanisms may facilitate the development of multiple organ failure (MOF), even as a consequence of apparently slight alterations in immune, cardiac or respiratory systems. Thus, prompt recognition and treatment of any complication often prevents the development of irreversible conditions. While cardiac and pulmonary complications account for 50% of early postoperative adverse events, infections, thromboembolism, renal failure, stress ulcers and coagulation disorders may occur well after surgical procedures. An important part of postoperative geriatric care is the diagnosis and correction of fluid, electrolyte and acid-base disturbances. These disturbances may manifest as mild, atypical signs, such as slight neuromuscular depression or delirium. Yet, they often constitute life-threatening conditions that should be rapidly and properly corrected. Finally, it should be remembered that, due to the frequent use of multiple drugs, elderly patients are at high risk of developing adverse drug reactions. Thus, the treatment of postoperative complications requires a strong rational effort to disentangle the combined effects of aging, drugs and pathology.