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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