Pre And Postoperative Serum Albumin Levels As Predictors Of Surgical Outcome

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Simi T., Uma Maheswari M.,* Sapna Shrikumar, Ravi T.K.
Department of Pharmacy Practice, College of Pharmacy, Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore-641044. *For correspondence


ABSTRACT


The study was carried out to determine whether surgical patients with a serum albumin level <3.5g/dL o­n admission to hospital have a longer duration of hospitalization than those with normal levels. Also estimation of postoperative albumin level was carried out to correlate the effect of surgery o­n albumin level. A total of 140 patients consecutively admitted to the department of General surgery, Cardiology, Neurology and Gastroenterology were studied. Their pre and post albumin levels were measured. Subsequent length of hospitalization was also recorded. Length of hospital stay was inversely related to admission serum albumin levels. The mean length of hospital stay for patients with serum albumin levels > 3.5g/dL was 14.84 ± 0.69 days, whereas the mean length of hospital stay for patients with albumin level < 3.5 g/dL was 22.0 ± 1.81 days. There was a significant decrease in albumin level following surgery. Serum albumin level is a reliable predictor of length of hospitalization.




INTRODUCTION


Albumin is the predominant protein in the blood and is responsible for many important functions. In recent years, it has been established that there is a direct correlation between risk of cancer, heart attack and overall longevity to a person’s albumin level. The higher a person’s albumin level, the lesser the risk of cancer or heart attack, and the more likely they were to maintain disease free[1] .
Albumin is involved in at least sixty five different biological functions. It is our body’s main transport system carrying vitamins, minerals, hormones, fatty acids and other essential substances to their destinations. It is also o­ne of our body’s most powerful and by far the most voluminous antioxidant. Given the fact that albumin is involved in so many essential functions, it is not accidental that there is a well-established correlation between low albumin level and mortality. A large number of studies have identified low albumin levels as the most consistent marker for imminent death[2].
In 1968 the World Health Organization published a monograph o­n the assessment of nutritional status of a community and concluded that blood serum albumin level should be used as the primary index of protein calorie malnutrition in hospitalized patients. This recommendation has stood the test of time.
Serum albumin was found to be the strongest predictor of preoperative patient risk variables of both mortality and morbidity for surgery as a whole and for a range of sub-specialties. Serum albumin level was also the best predictor of infective illness following surgery . A fall in serum albumin level has been shown to be associated with a fall in important serum proteins of the immune system, which are essential for resistance to infection and to many toxic substances .
The US National Surgical Risk Study reported “Serum albumin concentration is a better predictor of surgical outcomes than many other preoperative patient characteristics. It is a relatively low cost test that should be used more often as a prognostic tool to detect malnutrition and the risk of adverse surgical outcomes”. Overwhelming data has confirmed that albumin is an effective marker of general nutrition . Low albumin levels can increase the likelihood of post-surgery complications by as much as 50%. We conducted the study since in our hospital o­nly a few surgical patients are tested for their admission serum albumin level.




METHODOLOGY


Over a 6 month period, 140 patients consecutively admitted to the departments of general surgery, cardiology, neurology and gastroenterology were included for the study. All the patients had a thorough history and physical examination, routine admission laboratory studies and pre and postoperative serum albumin levels measured within 24 hours of admission and 4 days after surgery respectively. Serum albumin was measured according to standard laboratory procedure . The treating physicians were not blinded to the serum albumin value. Patients were divided into different categories based o­n the primary reason for admission: cardiac, neurological, gastrointestinal and general surgery. Patients were also stratified by age categories: 4 months –1 year, 1 – 10 years, 20 – 40 years, 40-50 years, 50-60 years and 60-70 years. An albumin level =3.5g/dL was considered normal. Postoperative albumin level was measured to confirm that physiologic stress following surgery reduces albumin level even in the face of good nutrition. The main outcome measure was length of hospital stay in days for each patient.
Paired ‘t’ test was used for the analysis of pre and postoperative serum albumin levels. Student ‘t’ test was used to compare length of hospital stay with pre operative albumin level above and below 3.5g/dL. Values were given as mean ± SEM.


RESULTS


During the 6 month period, 140 patients were included for the study. There were 84 males (60%) and 56 females (40%). Most of the patients were between 40-70 years. The mean admission albumin level was 3.77±0.03 (±SEM; range, 3.3-4.7g/dL) and the mean length of hospital stay was 15.55±0.69 days (SEM; range, 7-30 days). There were 14 patients (10%) with a mean serum albumin level of 3.35±0.02 g/dL and it reduced to 2.61±0.06 g/dL following surgery. There were 126 patients (90%) with a mean serum albumin level of 3.82±0.03 g/dL and it reduced to 3.43±0.03 g/dL after surgery (p<0.001) [Table 1].
The length of stay was inversely related to admission serum albumin level. [Figure 1] The mean length of hospital stay for patients with an admission serum albumin level <3.5g/dL was 22.0±1.81 days and 14.84±0.69 days for those with an admission serum albumin level=3.5 g/dL. [Table 2].
No mortality was observed during the study. There was no significant difference in length of stay by sex.
There was a decline in mean admission serum albumin value with advancing age, 3.36 g/dL for patients between 65-70 years and 3.47g/dL for those between 60-65 years.


DISCUSSION


Albumin is the most abundant extra cellular protein. It is manufactured in the liver at a rate of 9-12g/day. Production is controlled by changes in colloid osmotic pressure and osmolality of extra vascular liver space . Albumin has a role in maintaining colloid o­ncotic pressure, binding and transport, free radical scavenging, acid base balance, coagulation and vascular permeability. The average adult human liver produces approximately 15g of albumin daily, which is secreted into the plasma (within 30 minutes) and has a serum half life of approximately 21 days. The liver does not store excess albumin, and as a result when hepatic production ceases, serum levels decline. A fall in serum albumin levels has been associated with a fall in important serum proteins of the immune system that are essential for resistance to infection and to many toxic substances . Blood serum albumin level can be used as the primary index of protein calorie malnutrition in hospitalized patients. Albumin levels may decrease due to infection, malignancy, renal and hepatic disease, burns and surgery.
Sex was found to have no effect o­n pre and postoperative albumin level. There was a decline in albumin level for patients between the age group 60-70 years. Albumin level decreases with advancement of age. In elderly patients who often have diminished drug clearance mechanisms, a low albumin level leads to an increase in the free biologically active form of the drug since many drugs are bound to albumin.
In the department of Cardiology, there was a considerable decline in albumin level for patients who underwent coronary artery bypass grafting and mitral valve replacement. Majority of the patients who underwent tumor excision were hypoalbuminemic in departments of General surgery and Neurology. In Gastroenterology, diagnostic laparoscopy was the major procedure that reduced albumin level.
12.5% of patients were found to be hypoalbuminemic during admission whereas it increased to 50% post operatively in General surgery. In Cardiology, preoperative hypoalbuminemic patients were o­nly 8% but it increased to 75.6% post operatively. The department of Neurology had 10% preoperative hypoalbuminemic patients whereas it increased to 40% after the surgery. In Gastroenterology, 14.3% were hypoalbuminemic before surgery and it increased to 42.8% after surgery. This shows that surgery is associated with a decline in serum albumin level.
The length of hospital stay for patients with albumin level < 3.5g/dL was more when compared to patients with normal serum albumin at the time of admission. Therefore hypoalbuminemia leads to prolonged hospitalization in surgical patients. This may be due to, decreased immune function and increased susceptibility to nosocomial infections since there is a significant decrease in albumin level following surgery .


CONCLUSION


Serum albumin level is a useful indicator of protein status, adequacy or deficiency. Estimation of preoperative albumin level may therefore identify patients at high risk for adverse outcomes after surgery. Serum albumin monitoring being a low cost procedure should be used o­n a regular basis in surgical patients within 24 hours. It should be obtained in surgical patients o­n admission to the hospital because levels may decrease shortly after admission due to cessation of hepatic albumin synthesis . Surgery in hypoalbuminemic patients should be carried out o­nly when their serum albumin level returns to normal. Depending o­n the clinical situation, the hypoalbuminemic patient should undergo multiple consultations with the gastroenterologist, nephrologist, surgeon, endocrinologist and dietician. Adequate nutrition with sufficient high biological value protein should be provided . Thus, albumin levels obtained with initial admission studies may serve as a simple, useful predictor of surgical outcome in patients.

Figure 1: Effect preoperative albumin level o­n length of hospital stay ( n= 140)
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Table 1 Comparison of pre and post operative albumin levels














Group
Preoperative


Postoperative

Serum albumin g/dL Serum albumin g/dL
n = 126*
n = 14**
3.82 ± 0.03 a
3.35 ± 0.02 a
3.43 ± 0.03 b
2.61 ± 0.06 b

* patients having albumin level >3.5g/dL
** hypoalbuminemic patients i.e., albumin level < 3.5g/dL.
a, b Values are mean ± SEM
Paired t test was used for analysis.
b P <0.001 is considered significant as compared to a; df = 6, 62.


Table 2 Comparison of preoperative albumin level with length of hospital stay











Group Pre operative serum albumin g/dL Length of stay
n =126*
n = 14**
3.82 ± 0.03 a
3.35 ± 0.02 a
14.84 ± 0.69 b
22.00 ± 1.81 b

* patients having albumin level >3.5g/dL
** hypoalbuminemic patients i.e., albumin level < 3.5g/dL.
Values are mean ± SEM
Student ‘t’ test was used for analysis.
b P <0.001 of b is considered significant as compared to a ; df = 6, 62.




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