Rate of Termination of Premixed Parenteral Nutrition (PN) in Surgical Patients Secondary to High Serum Electrolytes

Methods Study design and centres This is a prospective, cohort, multi-centre study, to be conducted at King Faisal Specialist Hospital and Research Centre, (KFSH & RC), Riyadh. The study has been approved by KFSH&RC Office of Research Affairs representing the institutional review board (IRB).

Subjects:

Sample Size Sample size has been calculated using Raosoft website based on the total surgical patients who receive PN support on monthly bases, which is 20 patients per month, and the duration of the data collection is expected to elapse 6 months. This makes the field population represented by 120 patients. According to a previous study that assessed need for bolus of electrolytes, 7% of the eligible patients are expected to have the outcome. Allowing for 5% margin of error and 95% confidence level the target sample size will be 72 patients from KFSH&RC. Collaborating centers withdrew from this study due to insufficient eligible patients given the COVID-19 pandemic.

Protocol Surgical patients starting PN will be screened for the inclusion and exclusion criteria by the investigators of the study. Eligible patients will be asked to sign a consent form.

All patients will start PN after normalization of the following electrolytes potassium, magnesium, and phosphorus according to standard. Premixed PN formula, Olimel N9E will be started at a rate of 45 mL per hour for all patients on day 1 of PN support. After the routine assessment by pharmacists, the PN rate will be increased at an increment of 10 mL per hour on daily basis, representing the target goal of protein of 2 gm per kg according to the ideal body weight (IBW) , is achieved. Patients enrolled in the study will be followed while on PN support until cessation of PN or after 30 days of support have elapsed.

All patients will get their potassium, magnesium, and phosphorus levels assessed daily in the morning for the first 7 days of PN initiation. After the first week of PN support, electrolytes will be assessed at a minimum of three times a week thereafter while on PN. High electrolyte levels that develop on the following day of their respective low levels and corrected with bolus will not be considered as induced by PN.

Patients who develop hyperphosphatemia, hypermagnesemia, hyperkalaemia will get their PN stopped immediately and replaced with dextrose 10% water solution to run at 50 mL per hour till 21:00.Premixed PN will commence again at the same rate of the corresponding day. Patients who develop a second episode of any hyperphosphatemia, hypermagnesemia, or hyperkalaemia on the preceding day obtained from a blood sample will be shifted to the compounded PN.

Inclusion criteria

• Patients admitted under the care of non-cardiac surgical services, whether planned for surgery or to manage a surgical complications that developed within 30 after surgery.
• Patients under the care of the following surgical teams: colorectal surgery, oncology surgery, general surgery, and thoracic surgery.
• Patients starting PN as a sole source for nutrition with feeding status is nil per os (NPO)
• Patients who receive sips of water or oral tablets will be included in this study.

Exclusion criteria

• Any degree of renal impairment defined as glomerular filtration rate < 60 mL/min/m2 as calculated according to the modification of diet in renal disease (MDRD) equation
• Morbid obesity defined as body mass index (BMI) of > 40 kg/m2.