A Pilot Analysis of the Association Between Anesthesia Induction Dosing and AKI in the Elderly Population

The first stage of this study proposes to perform a pilot observational study looking at the doses of propofol used for the induction of general anesthesia. We will determine the percent (as a function of age, Elixhauser score, ASA status) of patients who receive more than the FDA approved induction dosage. We estimate 30% with the power defined as the width of the 95 percent confidence interval around that number that is given by 80% power and n=500.

In the second stage, the investigators will look at the association between dose and the development of hypotension (in the time after induction and before surgical incision) and post-operative AKI among elderly patients at YNHH while controlling for age, Elixhauser score, and ASA status. The results of this study will also hopefully be used in a quality improvement project to prevent overdosing of the elderly patient population with induction anesthetic.

Hypothesis 1: Elderly patients are being overdosed (per FDA guidelines) with anesthetic agents for induction of general anesthesia.

Hypothesis 2: Overdose of anesthetic agents for induction of general anesthesia in the elderly population leads to an increased chance of developing AKI.

Hypothesis 3: Overdose of anesthetic agents for induction of general anesthesia in the elderly population leads to an increased chance of developing hypotension post-induction, which may contribute to development of AKI or vice-versa.

This research will be done via analysis of data and associated records contained in the Multicenter Perioperative Outcomes Group databases at Yale (the latter is a research database approved under HIC#1206010438).

The possible risks are primarily the risk to privacy that is inherent in any retrospective chart review. The benefit may be to suggest areas for quality improvement in induction practices for elderly patients at YNHH and elsewhere.

Inclusion criteria

• Patients age 65 or older who underwent induction of general anesthesia at YNHH
• Only first surgery for each patient within the time period is counted
• Only include patients who underwent intubation
• Only include patients who underwent induction by propofol bolus
• Only include patients who got at least 0.3mg/kg of propofol

Exclusion criteria

• Patients under the age of 65, patients who underwent monitored anesthetic care/conscious mediation for their procedures.
• Patients with renal failure and/or chronic kidney disease
• Patients who have a pre-operative systolic blood pressure <100