Trace elements are micronutrients that are of vital important importance to human health and are involved in the process of many key human functions including the immune response, antioxidant defense and wound healing. Deficiency in a single element can manifest with multiple systems and can have significant organ impact.

Research has shown correlation between deficiencies in trace elements and increased risk for infections, sepsis, multi organ failure and mortality. However relatively few studies examined the impact of perioperative changes in trace elements and patients' postoperative outcomes.

In this prospective observational cohort study, we aim to examine the impact of perioperative changes in trace elements on postoperative outcomes, morbidity and mortality.

This study will include patients aged 18 and above undergoing elective surgeries under general anesthesia at Rabin Medical Center. In the operating room blood samples will be collected from all study participants in the beginning of surgery and at the end of surgery.

Collected samples will be sent for analysis of periodic table elements to assess the perioperative period changes in trace elements measured in whole blood. Participants intraoperative and postoperative data will be collected. All postoperative complications will be documented. Perioperative changes will be correlated with participants' postoperative outcomes using computer analytical correlations.

Inclusion Criteria:

• Patients 18 and above
• Patients undergoing elective surgeries (as detailed above) under general anesthesia.
• Patients who can read and write Hebrew

Exclusion Criteria:

1. Emergency surgery
2. Regional anesthesia only

Patients aged 18 and above undergoing elective surgeries (including general surgery, neurosurgery, ear nose and throat surgeries, cardiac surgery, orthopedic surgeries, vascular surgeries and urological surgeries) at Rabin Medical Center under general anesthesia will be eligible for participation.