|Year : 2021 | Volume
| Issue : 2 | Page : 290-294
Usefulness of routine preoperative investigations in patients undergoing uncomplicated elective general surgical procedures
Kishan Danvath, Sridhar Matta
Department of Surgery, Government Medical College, Nalgonda, Telangana, India
|Date of Submission||25-Mar-2020|
|Date of Decision||18-Sep-2020|
|Date of Acceptance||10-Dec-2020|
|Date of Web Publication||18-Oct-2021|
Dr. Sridhar Matta
Government Medical College, Nalgonda, Telangana
Source of Support: None, Conflict of Interest: None
Background: Investigations are classified as routine and specific. Specific investigations are done to confirm or exclude a strongly suspected diagnosis, and routine investigations are done to find occult disease not detected during clinical evaluation. Mostly, these are done as an institutional policy or custom and for medicolegal reasons in the event of any complications. The value of these routine investigations in all patients is controversial. Data suggest that these have little influence on patient management and perioperative complications. Aims and Objectives: The objective of this study was to evaluate the usefulness of routine preoperative investigations in patients undergoing elective surgical procedures and their influence on perioperative management. Materials and Methods: We included various laboratory, radiological, and hematological investigations which were performed routinely in all patients irrespective of diagnosis. Results: A total of 1671 investigations were performed in 170 patients. Only 153 (9.2%) investigations were found to be abnormal. Complete blood picture was performed in 168 (98.2%) patients; random blood sugar estimation was done in 147 (86.4%) patients. Chest X-rays were performed in 166 (97.6%) patients. Electrocardiography was performed in 160 (94.2%) patients. The percentage of overall abnormal results was very low. None of these abnormal investigations influenced surgical management and had adverse perioperative complications. Conclusion: Preoperative investigations should be done based on clinical examination and comorbid conditions. Routine preoperative investigations do not influence patient management and predict complications and should not be done in all patients.
Keywords: Chest X-ray, electrocardiography, random blood sugar, routine investigations, serological tests
|How to cite this article:|
Danvath K, Matta S. Usefulness of routine preoperative investigations in patients undergoing uncomplicated elective general surgical procedures. J Datta Meghe Inst Med Sci Univ 2021;16:290-4
|How to cite this URL:|
Danvath K, Matta S. Usefulness of routine preoperative investigations in patients undergoing uncomplicated elective general surgical procedures. J Datta Meghe Inst Med Sci Univ [serial online] 2021 [cited 2021 Dec 4];16:290-4. Available from: http://www.journaldmims.com/text.asp?2021/16/2/290/328479
| Introduction|| |
Laboratory investigations before any surgery are common and are considered part of preanesthetic evaluation to identify patients at high risk of complications. Routine investigations are defined as minimum investigations done for all patients before any proposed surgical intervention. The list includes various hematological, serological, radiological, and other investigations. A key investigation is one that confirms or excludes a strongly suspected diagnosis. In contrast, routine investigations are performed before any surgery to have baseline values and find occult disease. Although the cost of each laboratory test is low, the aggregate cost is substantial. It is estimated that the cost of routine investigations is very high and 30%–90% are unindicated, and the practice of routine testing is debated. Ordering of investigations, though widespread in hospital practice, is wasteful of resources and is replaced by selective testing based on clinical findings. Abnormalities detected by such testing is very low and may range from 0.4% to 7% in asymptomatic patients. Thus, asymptomatic and healthy patients may undergo surgery without any investigations, while specific tests should be ordered based on clinical evaluation.
| Materials and Methods|| |
This study was conducted at Osmania General Hospital, a tertiary care teaching institute, in Hyderabad. A total of 170 patients of both sexes between the age group of 15 and 45 years were included. The data were collected from case records of the patients and followed up till the patients were discharged. In our study, we defined routine baseline investigations as those minimum investigations which were performed in all patients irrespective of disease, clinical findings, and comorbidities. These include complete blood picture, complete urine examination, cardiac echo Doppler, serum creatinine, blood urea, and serum electrolytes.
| Results|| |
A total of 1671 investigations were performed in all patients. All the test results viewed from the hospital laboratory reference range and were expressed either abnormal, normal, in numbers or symbols. Out of 1671 investigations performed, 153 (9.2%) were found to be abnormal [Table 1]. Complete blood picture was performed in 168 (98.2%) patients and found abnormal in 27 (16%) patients. Random blood sugar estimation was performed in 147 (86.4%) patients and found elevated blood sugar levels in 9 (6.1%) patients [Figure 1]. Blood urea and serum creatinine investigations were performed in 163 (95.8%) patients and found normal in all patients. Serum electrolyte investigations were performed in 155 (92%) patients and found abnormal in only 3 (1.9%) patients. Serological tests for human immunodeficiency virus (HIV) was performed in 170 (100%) patients and found positive in 5 (2.94%) patients [Figure 2]. HBSAG test was performed in 170 (100%) patients and found reactive in 4 (2.35%) patients. Chest X-ray (CXR) was performed in 166 (97.6%) patients and found abnormal radiological findings in 6 (3.61%) patients [Figure 3]. ECG was performed in 160 (94.2%) patients and found abnormal in 6 (3.75%) cases [Figure 4]. Moreover, the findings were tall T waves, old infarcts, and broad QRS complex. Cardiac echo Doppler test was performed in 74 (43.5%) patients and found abnormal in 3 (4%) patients. Liver function test was performed in 37 (22%) patients and found abnormal in 10 (27%) patients. Thyroid function test was performed in 19 (12%) patients and found abnormal in 4 (21%) patients. Serum electrolyte investigations were performed in 155 patients and found abnormal in 3 (1.9%) patients.
|Table 1: Total number of routine tests performed and the percentage of abnormal test results (n = 1671)|
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|Figure 2: Routine virological screening for human immunodeficiency virus and percentage of abnormal results (n = 170)|
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|Figure 3: Percentage of normal and abnormal chest X-ray results in 166 patients|
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|Figure 4: Percentage of normal and abnormal electrocardiography in 160 patients|
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| Discussion|| |
Many physicians order a battery of investigations before surgery as a policy or custom. The practice is expensive and leads to undue delay of surgeries, and if abnormalities are detected, it may have no significant influence on outcome and may prompt for further investigations which may be of no clinical significance. Most commonly done routine tests include complete blood tests, urine analyses, electrocardiography (ECG), and CXRs. Others include two-dimensional (2D) cardiac echo Doppler, serological tests for HIV, and HBsAG test. Several reasons compel physicians to order these investigations; these include detection of undiscovered abnormalities during clinical evaluation to establish baseline values. The third reason is for medicolegal reasons in the event of any unexpected complications.
In a comparative study involving 163 patients scheduled to undergo elective surgical procedures, a total of 984 preoperative tests were performed. Of these, 515 (52%) tests were unindicated as per nice guidelines. Out of these, 7 (1.3%) test results were found to have abnormal values and none of these findings altered anesthesia plan, cancellation of surgery, and prompted for further investigations. The most common unindicated tests were cardiac 2D echo and CXR, which accounted for 92.5% and 93%, respectively. They concluded that preoperative investigations should be based on surgical grade and preoperative condition of patients.
The presence of anemia may increase morbidity and mortality due to tissue hypoxia. Major surgery can lead to significant blood loss and worsen the situation. Thus, routine estimation of hemoglobin preoperatively in patients expected to have significant operative blood loss is justified. In a retrospective study involving 292 patients undergoing major and minor surgeries, abnormal hemoglobin result was found in only 0.3% of patients and had no influence on surgical outcome. In a similar study by abnormal result of hemoglobin, estimation was found in only 0.8% (160) of patients out of 3782 in American Society of Anesthesiologists (ASA) Class 1. Out of these 160 abnormal results, 30% could be detected clinically. In our study, hemoglobin estimation was performed in 168 patients and 27 (16%) patients were found to have decreased hemoglobin levels (<mg/dl) and anemia could be identified on clinical examination in 20 patients. None of these patients required blood transfusions preoperatively and change in surgical management and increased perioperative complications.
Preoperative ECG is commonly performed in patients with suspected cardiac disease that would increase cardiac complications postoperatively. However, mere presence of these finding on ECG does not predict postoperative cardiac complications. In a retrospective study involving 1000 ASA Class 1 and 2 patients, it was found no differences in postoperative cardiac complications between normal and abnormal ECGS. They reviewed ECGs of adult patients between 18 and 88 years of age. Of which, 56.5% were considered normal, 37.8% were abnormal, and 6.6% were considered borderline. Twenty-seven percent of patients presented with cardiovascular risk factors. Seventy-three percent of patients had no cardiovascular risk factors. Patients who had cardiovascular risk factors had significantly more abnormal ECGs than those without (51% vs. 26.1%, respectively). Patients with abnormal ECG had slightly increased perioperative cardiac events than those without (42.7% vs. 34.7%, respectively). They concluded that the practice of routine ECG screening for patients with no cardiovascular risk factors is a poor predictor of perioperative complications. In our study, ECG was performed routinely in 160 patients whose age was more than 30 years with no significant history of cardiac disease. We found abnormal ECGs in 6 (4%) patients; most abnormalities were tall T waves and old Q waves. All these patients had 2D cardiac echo as part of cardiologist evaluation. None of our patients needed further cardiac intervention and there were no significant postoperative cardiac complications.
Serum electrolyte levels are commonly measured in patients who are on diuretics, cardiac failure, or in whom significant changes in electrolyte changes may happen in the postoperative period. The presence of electrolyte abnormalities may increase the risk of anesthetic complications such as arrhythmias due to serum potassium changes and produce paralytic ileus. In a study by Turnbull and Buck et al., routine screening of 995 patients for serum electrolyte changes who were undergoing laparotomy for various causes, serum potassium determinations revealed mild changes (3.2 and 3.4 mEq/l [3.2 and 3.4 mmol/l]) in only two patients who were otherwise asymptomatic and was not suspected on clinical evaluation and did not require any action and had incereased postoperative complications. Similarly, in another study by Kaplan, no abnormalities in serum potassium levels in 514 patients who were undergoing routine preoperative testing for uncomplicated surgeries was observed. In our study, serum electrolyte estimation was performed in 155 (91.2%) patients who were otherwise asymptomatic and/or on any medications. Serum electrolyte estimations were part of routine evaluation. We found low serum potassium levels in only three patients (2.0, 2.9, and 1.9 mEq/l, respectively). These patients were given potassium supplementation preoperatively and repeat test after 3 days was found to be normal. None of these abnormalities had any influence on postoperative outcome.
Renal insufficiency is one of the important risk factors for postoperative complications. In a revised cardiac index by Lee et al., preoperative serum creatinine value of more than 2.0 g/dl was one of the six predictors of risk factors for postoperative complications. Recent revised guidelines by the American College of Cardiology and the American Heart Association also categorize renal insufficiency as an intermediate risk predictor for postoperative complications. Charpak et al. in a retrospective study in 995 patients who underwent various noncardiac surgeries found abnormality in renal function tests on routine testing in only 26.2% of cases and had influence on management in only 5.5% of cases. In a similar study by Sanders et al., abnormal creatinine levels were observed in only 1.15% of cases out of 95 patients who were undergoing total hip arthroplasty and had no influence on perioperative outcome. In our study, out of 163 patients in whom renal function tests were performed, only 1 (0.6%) patient had abnormal result, and on repeat testing, it was found to be normal and had no influence on surgical management.
CXR is one of the most commonly performed routine radiological investigations as this is widely available in many hospitals. Many of X-ray changes may simply reflect age-related changes or may not have any significance when further tested. Its use is rampant despite published guidelines regarding ordering of routine CXRs in patients with apparently no cardiopulmonary disease. The benefit of CXR performed as part of preoperative evaluation process has long been questioned. In a prospective study by Rees et al., chest radiography was performed in 667 consecutive patients undergoing elective uncomplicated surgery, 18% of patients were found to have abnormal CXRs, no change in surgical management took place, and no postoperative complications were observed in those cases. They observed that CXR should be ordered in patients with an age >50 years and those with known cardiopulmonary disease and with symptoms or findings that suggest a cardiopulmonary disease. In a review study by Joo et al., most of the abnormalities on chest radiography consisted of chronic disorders such as chronic obstructive pulmonary disease and cardiomegaly (in up to 65% of patients), and when investigated subsequently, they influenced patient management in only 10% of patients. It was also observed that postoperative complications were similar in patients who had preoperative CXRs (12.8%) and who did not have (16%). From the above review study, they opined that preoperative chest radiographs did not reduce mortality and morbidity; further, they also observed that the prevalence of abnormalities on preoperative CXRs was low in patients below 70 years of age and should not be performed routinely without any risk factors in patients below this age group. Diagnostic yield of preoperative CXRs increased with age and most of abnormalities reflected age-related chronic disorders and had no significance. The clinical practice guidelines published by the Guidelines Advisory Committee and supported by the Ministry of Health and Long-term Care in the Ontario Medical Association advocate that routine preoperative CXR is not warranted routinely. Few studies reported that abnormalities found on routine chest X-ray led to further investigations in 47%, 4%, and 2.4%, respectively, by Umbach, Wiencek,and Silvestri. However, in 90% of patients, further investigations led to no change in management. In a large retrospective study by the Royal College of Radiologists, it was found that there was no difference in complications in patients with normal and abnormal CXRs who received inhalational anesthesia. In a study by Sommerville TE et al., delay in surgery occurred in 1.3% of patients in their study group based on preoperative CXR changes. In a similar study by Sommerville, changes in surgical management happened in only 1% of patients with no risk factors and 4% of patients with risk factors.
In our study, preoperative CXRs were performed in 166 (97.6%) patients, of which only 6 (3.6%) patients had abnormal radiological findings. These include increased bronchovascular markings in three patients which represented age-related changes, healed tuberculous lesions in two patients with no past history of tuberculosis a, mild cardiomegaly with unfolding of aorta in one patient with systemic hypertension. A patient with cardiomegaly was further investigated by ECG and 2D cardiac echo and found to have right ventricular wall motion abnormality with ejection fraction of 62%. None of these patients required change in anesthesia and surgical management and had no adverse postoperative outcome.
Established diabetes or elevated blood sugars can increase surgical risk. There is an increased incidence of wound complications and impaired healing of wounds; patients can also have associated renal and cardiovascular complications. In a revised cardiac index by Lee et al., diabetes requiring insulin therapy was 1 of 6 independent risk factors for increased postoperative complications. Whether a similar risk exists in patients without a clinical diagnosis of diabetes who are found to have elevated blood sugars on routine preoperative testing is not known. In a study by the ASA out of 3782 Class I or Grade1 patients, only 16 patients had abnormal blood glucose values that prompted further assessment. Only one patient was found to have established diabetes, and five other patients were advised delay of surgery and lose weight due to elevated blood sugars and other risk factors. In a retrospective study, abnormal blood glucose values were found in only 5.4% of cases out of 464 patients and only 0.4% of those abnormal results influenced perioperative management. In a similar study, out of 412 patients undergoing oral and maxillofacial surgery of ASA Class 1 and 2, they found only 0.2% of abnormal blood glucose results, and none of these results had an impact on management on these patients. Given the low incidence of unsuspected diabetes (0.5%) among patients undergoing surgery and the lack of evidence that identification and treatment of patients with clinically occult diabetes reduces postoperative complications, it is not recommended to do routine preoperative measurement of serum glucose estimations. In a retrospective study by Perez et al., out of 2772 patients in whom blood glucose estimation was done, only 2.2% of patients found to have abnormal results and only 0.2% of abnormal tests influenced management. In another study, serum glucose estimation was performed in 548 patients who were scheduled to undergo uncomplicated surgeries and found blood glucose abnormality in 10 (1.8%) patients only and found no significant influence on surgical management. Such measurements are helpful; however, as part of the perioperative management of patients with known diabetes, clinicians may consider preoperative testing of serum glucose in patients with symptoms that suggest undiagnosed diabetes. The available literature does not, however, allow a firm recommendation about the value of such screening. In our study, random blood sugar estimation was performed in 147 (86.4%) patients and found elevated in only 9 (6.1%) patients. Four patients were known diabetics and taking oral hypoglycemic drugs. In only two patients with abnormally high values, surgery was postponed due to other coexisting comorbid conditions.
Screening for blood borne viruses is commonly performed in many patients. While many people favor routine screening in all patients to reduce risk of transmission. Few advocate universal precautions to reduce transmission of those diseases. Screening for HIV and hepatitis B and C are one of the most commonly performed investigations in our study. While testing for this is important to reduce risk of transmission, these have no direct effect on perioperative complications; mere presence of this may lead to cancellation of surgery or change in the surgical. In our study, we performed these tests in 170 (100%) patients and found reactive for HIV antibodies in 5 (2.9%) patients. Hepatitis surface antigen test was done in 170 (100%) patients and found positive in 4 (2.35%) patients; none of these had any influence on outcome.
| Conclusion|| |
From our study, we conclude that routine investigations are commonly performed as a matter of policy and custom irrespective of surgical procedure and comorbidities in the patient. Most commonly performed investigations were CXRs, ECG, 2D cardiac echo, complete blood picture, blood glucose estimation, and others. The percentage of overall abnormal investigations was very low. Literatures suggest that routine investigations should not be ordered routinely in all patients. Selective ordering of investigations should be undertaken based on findings and comorbid conditions. Perioperative complications could not be reliably from routine investigations.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]