AMELIA CRAWFORD, PA-S2OCTOBER 28,2011

Nutritional Supplementation and Serum Albumin Levels: Their Usefulness in Predicting and Improving Operative

Morbidity and Mortality in the Geriatric Population

Preoperative Testing

Purpose is to identify underlying abnormalities or assess the severity of a current condition that may affect patient morbidity and mortality

For the geriatric patient, the clinician must strike a balance between routine testing and extensive evaluation.

Preoperative Testing

Best tools are history and physical exam:

Patient’s overall health Cognitive Functioning Nutritional Status Family & Social Support Medication Review

Routine Tests

CBC: Hemoglobin- minimum of 9-10 mg/dl. WBC- identify any infections or underlying myeloproliferative

disorders

Basic Metabolic Panel: Electrolytes: may be abnormal due to use of diuretics or

ACEI/ARB Creatinine Clearance- important for postop med dosing Preop Serum Creatinine of >2.0mg/dl is a predictor of post op

cardiac complications in patients undergoing non-cardiac surgery Albumin level- assess nutritional status

Coagulation Studies: PT, PTT, INR

Routine Tests

EKG: For males>40-45 YOA & females>55 YOA, patients

with systemic diseases like HTN, DM, PVD, hyperlipidemia, cerebrovascular disease, those taking medications that increase risk for cardiac toxicity

Helps identify patients with previous infarcts, which increases risk of complications

Chest X-Ray: Patients >50 YOA & those cardiopulmonary or with

pre-existing pulmonary disease Risk of complications from anesthesia

Nutritional Assessment

Geriatric population is at risk for deficiencies because appetite and calorie consumption often decrease

In those with nutritional deficiencies there is sometimes concomitant depression, isolation, poor dentition, or excessive alcohol consumption

BMI: <18.5 is cause for concernHealing is delayed in the presence of even mild

protein calorie malnutrition. Studies suggest that early recognition of protein

malnutrition and initiation of nutritional therapy can shorten the length of hospital stays and improve patient outcomes

Serum albumin & pre-albumin are often used as nutritional status markers

Albumin

Complex, high molecular weight protein produced by the liver

Widely used in nutritional assessmentHalf-life of 18-20 daysNormal value: 3.30 to 4.80 g/dLAffected by many factors including

dehydration, inflammation, hepatic and renal dysfunction

The level typically takes 14 days to return to normal when the pool has been depleted.

Pre-albumin

A serum and cerebrospinal fluid carrier of the thyroid hormone thyroxine (T4) and retinol, produced mainly by the liver.

Lower levels correlates with protein malnutrition (within 1 week of change in nutrient intake).

Not affected by dehydration but systemic inflammation does cause a decrease.

Clinical studies indicate that determination of the pre-albumin level may allow for earlier recognition of and intervention for malnutrition.

Synthesis of pre-albumin increases above baseline levels within 48 hours of protein supplementation in patients with protein calorie malnutrition and returns to normal levels within eight days.

½ life of 2-3 days Normal level: 16-35 mg/dL

GIBBS ET AL. ARCHSURG. 1999; 134; 36-42

Preoperative Serum Albumin Level as a Predictor of Operative

Mortality and Morbidity

Background Information

Hypoalbuminemia has been shown to be associated with increased mortality and morbidity rates in hospitalized and community dwelling elderly persons.

Hypoalbuminemia has also been associated with adverse outcomes after surgery.

Objective

To improve precision and reliability of estimates of the association between preoperative serum albumin concentration and surgical outcomes

Design

Prospective observational studySetting: 45 VA medical centersPatients: 54,215 major non-cardiac surgery

cases from the National VA Surgical Risk Study 97.1% male Mean age was 61 years 76% white, 18% black, 6% other ethnicities General surgery (28.3%), Orthopedic (18.0%), Urology

(14.8%), Vascular (11.7%), Neurosurgery (8.4%), Thoracic (7.3%), ENT (5.9%), Plastic (3.7%), Other (2.0%)

Data collected until 30 days post-operatively

Design

Independent Variables: 1. Serum albumin values closest to the day of the

surgery (within 30 days)

Dependent Variables: 1. Operative Mortality: death due to any cause within

30 days of the operation 2. Operative Morbidity: 21 of the predefined

complications recorded within 30 days of the operation.

Primary Outcome

30 day operative mortality and morbidity

Stastical Analysis

Univariate Analyses- association between preoperative serum albumin levels and mortality and morbidity. Compared the predictive ability of albumin level with that of each of 61 other preoperative variables.

Multivariant Logistic Regression Analyses- assess the predictive ability of albumin level independent of the effects of other variables.

Complication-Specific Analyses- association between preoperative serum albumin and each of 21 pre-defined complications

Results

Univariate Analysis: 1. Albumin level was the best predictor of 30 day

mortality and morbidity. 2. Albumin level alone correctly discriminated

between survivors and non-survivors 78% of the time For all operations, the mortality rate increases from

less than 1% for albumin levels of 46g/L or higher to 28% for albumin levels below 21g/L

Results

Results

Multivariate Analyses: Albumin level is the strongest predictor in both

mortality and morbidity models for all operations and in several subspecialty models

Odds ratios for albumin level in all operations models indicate that a decrease of 10g/L in albumin value was associated with more than a 2 fold increase in the odds of dying and almost a 2 fold increase in the odds of a complication.

Results

Complication-Specific Analysis:

Albumin level was a relatively strong predictor of most of the complications: particularly systemic sepsis, failure to wean off the

ventilator, and pneumonia

Results

Results

Separate analyses were performed for a lower risk segment of the sample and for women, and there was a negative association between serum albumin level and 30 day mortality for both groups.

Summary of Results

A decrease in serum albumin from concentrations greater than 46g/L to less than 21g/L was associated with an increase in mortality rates from less than 1% to 29% and in morbidity rates from 10% to 65%.

In regression models, albumin level was the strongest predictor of mortality and morbidity as a whole and within several subspecialties (independent of the effects of other risk variables)

Albumin level was a better predictor of some types of morbidity, particularly sepsis and major infections.

Level of Evidence

CARRETERO ET AL. CLINICAL NUTRITION

OCTOBER 2010VOL. 25; ISSUE 5: 574-579

Perioperative Oral Nutritional Supplements in Normally or Mildly Undernourished Geriatric Patients

Submitted to Surgery for Hip Fracture: A Randomized Clinical Trial

Objectives

To study whether perioperative administration of oral nutritional supplements (ONS) are effective in geriatric patients undergoing surgery for hip fracture, starting at admission.

Design

Randomized control trial Patients:

60 patients total >65 YOA Admitted between May 2005 and September 2008 due

to hip fracture and underwent hip surgery No patients had been on ONS or received any other

nutritional support within the previous 6 months All patients had similar baseline characteristics

Exclusion Criteria

1. Moderate to severe malnutrition: Weight loss of > 5% in the previous month or >10% in

the previous 6 months of their usual body weight

ARF, CRF, Hepatic Insufficiency or Cirrhosis, Stage III or IV HF, Repiratory Failure, GI conditions that precluded the use of ONS

Interventions

Control Group (n=30): no interventionIntervention Group (n= 30): Perioperative ONS

initiated at admission and maintained until discharge 2 Fortimel 200mL bricks which provided 20g protein & 200 kcal Amount of ONS and diet consumed by the patient was

measured after every meal.

Blood testing and body measurements were done at baseline, 48 hrs after surgery, then weekly, and also at hospital discharge. Normal ranges:

Serum albumin = 3.3-5.2g/L Pre-albumin = 20-40mg/dL RBG are as follows= 3.0-6.0mg/dL

Outcomes

Primary: 1. Change in albumin, pre-albumin, and retinol

binding globulin. 2. Changes in weight, BMI, mid-brachial

circumference, and tricipital fold

Secondary: 1. Length of hospital stay 2. Postoperative complications

Statistics

Comparisons between both groups at baseline were performed using the independent Student t test, Mann-Whitney U test, or Chi-Square test

General linear model was used for the comparison of continuous variables throughout the study

Backwards multiple logistic regression model was employed to study the effects of multiple independent variables on the occurrence of post-operative complications

Results

Primary Outcomes: There was a significant change in albumin between the 2

groups (F=22.536, P<0.001) from the time of admission until the time of discharge, with the control group demonstrating a larger decrease in serum albumin and worse post-op recovery compared to the ONS group.

Serum pre albumin also demonstrated similar significant changes (F=6.654, P=0.001)

RBG demonstrated a similar change, but this difference was not significant (F= 2.281, p=0.089)

No significant differences in the change in BMI (F=2.509, P=0.089), tricipital fold (F=0.584, P=o.636), or the mid-brachial circumference(F=0.031, P=0.864) between the groups.

Results

Open circles = control groupFilled circles= ONS group

Results

Secondary Outcomes: Length of postoperative hospital stay was similar in

the 2 groups (p= 0.664) No significant difference in postoperative

complication rates between the 2 groups (p= 0.091) Non-significant tendency for higher postoperative

complication rate in the control group, but no specific complication could be identified as predominant in either group.

Results

Ancillary Analyses: Backwards multiple logistic regression analysis with

the occurrence of postoperative complication as the dependent variable and age, gender, baseline BMI, mid-brachial circumference & tricipital fold, non-protein, and supplemented proteins per day as covariates. The supplemented proteins per day was determined to be

a predictive variable ( OR= 0.925; 95% CI; P= 0.003) Suggests that higher protein intake is associated with a

smaller risk of postoperative complications

Conclusions

Perioperative administration of ONS is effective in increasing serum proteins in nourished or mildly nourished geriatric patients who undergo surgery for hip fracture.

Patients with higher protein intakes had fewer postoperative complications

Level of Evidence

Final Comments

Serum albumin and pre-albumin levels are used frequently to monitor nutritional status. However, these markers are affected by more than just

protein nutrition. Levels should be interpreted along with weight, BMI,

physical exam, and other labs.

They are cost effective labs that can help predict the risk of postoperative morbidity and mortality in geriatric patients

In geriatric patients undergoing surgery, correcting nutritional deficits before and after surgery can help prevent complications and improves mortality rates.

References

Shenkin, Alan. Serum Prealbumin: Is It a Marker of Nutritional Status or of Risk of Malnutrition? Clin. Chem., Dec 2006; 52: 2177 - 2179.

Beck FK, Rosenthal TC. Prealbumin: a marker for nutritional evaluation. Am Fam Physician. Apr 2002; 15;65(8):1575-8.

Woogler, JM. “Preoperative Testing and Medication Management.” Clinics in Geriatric Management, Nov 2008; 24 (4): 573-583.

Carretero et al. Perioperative oral nutritional supplements in normally or mildly undernourished geriatric patients submitted to surgery for hip fracture: A randomized clinical trial. Clinical Nutrition, Oct 2o1o; 29 (5):574-579

Gibbs et al. Preoperative Serum Albumin Level as a Predictor of Operative Mortality and Morbidity. Arch Surg. 1999;134:36-42