Relevance of routine testing in low-risk patients undergoing minor and medium surgical procedures

Abstracts

JUSTIFICATIVA E OBJETIVOS: A avaliação pré-operatória tem como objetivos diminuir a morbimortalidade do paciente cirúrgico, o custo do atendimento perioperatório e a ansiedade pré-operatória. A partir da avaliação clínica deve-se definir a necessidade de exames complementares e estratégias para reduzir o risco anestésico-cirúrgico. O objetivo deste trabalho foi avaliar o benefício de exames de rotina pré-operatório de pacientes de baixo risco em cirurgias de pequeno e médio porte. MÉTODOS: Trata-se de um estudo descritivo, transversal, com 800 pacientes atendidos no consultório de avaliação pré-anestésica do Hospital Santo Antonio, Salvador, BA. Foram incluídos pacientes de 1 a 45 anos, estado físico ASA I, que seriam submetidos a cirurgias eletivas de pequeno e médio porte. Avaliaram-se alterações no hemograma, coagulograma, eletrocardiograma, RX de tórax, glicemia, função renal e dosagem de sódio e potássio e as eventuais mudanças de conduta que ocorreram decorrentes dessas alterações. RESULTADOS: Dos 800 pacientes avaliados, 97,5% fizeram hemograma, 89% coagulograma, 74,1% eletrocardiograma, 62% RX de tórax, 68% glicemia de jejum, 55,7% dosagens séricas de ureia e creatinina e 10,1% dosagens de sódio e potássio séricos. Desses 700 pacientes, 68 (9,71%) apresentaram alteração nos exames pré-operatórios de rotina e apenas 10 (14,7%) dos considerados alterados tiveram conduta pré-operatória modificada, ou seja, solicitação de novos exames, interconsulta ou adiamento do procedimento. Nenhuma das cirurgias foi suspensa. CONCLUSÃO: Observou-se que excessivos exames complementares são solicitados no pré-operatório, mesmo em pacientes jovens, de baixo risco cirúrgico, com pouca ou nenhuma interferência na conduta perioperatória. Exames aboratoriais padronizados não são bons instrumentos de screening de doenças, além de gerar gastos elevados e desnecessários.

AVALIAÇÃO, Pré-anestésica; EXAMES COMPLEMENTARES; CIRURGIA, Cuidados préoperatórios; Procedimentos Desnecessários

OBJETIVOS Y JUSTIFICATIVA: La evaluación preoperatoria tiene el objetivo de disminuir la morbimortalidad del paciente quirúrgico, el coste de la atención perioperatoria y la ansiedad preoperatoria. A partir de la evaluación clínica debemos definir la necesidad de exámenes complementarios y de estrategias para reducir el riesgo anestésico-quirúrgico. El objetivo de este trabajo fue el de evaluar el beneficio de exámenes de rutina preoperatorio de pacientes de bajo riesgo en las cirugías menores. MÉTODOS: Se trata de un estudio descriptivo, transversal con 700 pacientes atendidos en la consulta de evaluación preanestésica del Hospital Santo Antonio, Salvador, BA. Fueron incluidos pacientes de 1 a 45 años, estado físico ASA I, que serían sometidos a cirugías electivas menores. Se evaluaron las alteraciones en el hemograma, el coagulograma, el electrocardiograma, RX de tórax, glucemia, función renal y dosificación de sodio y potasio, y los eventuales cambios de conducta que se suscitaron provenientes de esas alteraciones. RESULTADOS: De los 800 pacientes evaluados un 97,5% realizaron hemograma, 89% coagulograma, 74,1% electrocardiograma, 62% RX de tórax, 68% glucemia en ayunas, 55,7% dosificaciones séricas de urea y creatinina y un 10,1% dosificaciones de sodio y potasio séricos. De esos 800 pacientes, 68 (9,71%) tuvieron alteración en los exámenes preoperatorios de rutina y solo 10 (14,7%) de los considerados alterados tuvieron una conducta preoperatoria modificada, o sea, una solicitación de nuevos exámenes, interconsulta o la postergación del procedimiento. Ninguna de las cirugías se suspendió. CONCLUSIONES: Observamos que los excesivos exámenes complementarios se solicitaban en el preoperatorio, aunque fuese en los pacientes jóvenes y de bajo riesgo quirúrgico, con poca o ninguna interferencia en el conducta perioperatoria. Los exámenes laboratoriales estándares no son buenos instrumentos de screening de enfermedades y pueden generar gastos elevados e innecesarios.

AVALIACIÓN, Preanestésica; EXÁMENES COMPLEMENTARES; CIRUGÍA, Evaluación Preoperatoria; Procedimientos innecessarios

SCIENTIFIC ARTICLE

^IPhD in Anesthesiology, Universidade Estadual Paulista Júlio de Mesquita Filho, Brazil; CET-SBA - Centro de Ensino e Treinamento em Anestesiologia das Obras Sociais Irmã Dulce - Hospital Santo Antonio, Salvador, BA, Brazil

^IIAnesthesiologist, Hospital Santo Antonio, Salvador, Bahia, Brazil

Corresponding author

ABSTRACT

BACKGROUND AND OBJECTIVES: Preoperative tests aim to reduce morbidity and mortality of surgical patients, cost of perioperative care, and preoperative anxiety. Clinical evaluation allows defining the need for additional tests and strategies to reduce the surgical-anesthetic risk. The aim of this study was to evaluate the benefit of routine preoperative testing of low-risk patients undergoing minor and medium surgical procedures.

METHODS: A descriptive cross-sectional study of 800 patients seen at the preanesthetic assessment department of Hospital Santo Antonio, Salvador, BA. Patients with physical status ASA I, aged 1-45 years and scheduled to undergo elective minor and medium surgeries were include in the study. We evaluated changes in blood count, coagulation profile, electrocardiogram, chest X-ray, blood sugar, kidney function, sodium and potassium levels, and eventual change in clinical approach occurring due to these changes.

RESULTS: Of 800 patients evaluated, a blood count was performed in 97.5%, coagulation in 89%t, electrocardiogram in 74.1%, chest X-ray in 62%, fasting glucose in 68%, serum urea and creatinine in 55.7%, and plasma levels of sodium and potassium in 10.1%. Of these 700 patients, 68 (9.71%) showed changes in preoperative routine tests and only 10 (14.7%) of the patients with abnormal tests had a preoperative modified approach (i.e., new tests ordered, referral to a specialist or surgery postponement). No surgery was suspended.

CONCLUSION: We found that preoperative additional tests are excessively ordered, even for young patients with low surgical risk, with little or no interference in perioperative management. Laboratory tests, besides generating high and unnecessary costs, are not good standardized screening instruments for diseases.

Keywords: Diagnostic Tests, Routine; Unnecessary Procedures; Preoperative Care.

Introduction

Preoperative evaluation is aimed at reducing morbidity associated with surgical-anesthetic procedures and, preferably, should be performed by the anesthesiologist¹. When the anesthesiologist takes responsibility for preoperative tests, he can get a more appropriate clinical profile and consequently reduce surgery cancellations due to inadequate laboratory evaluation^2-3. Another aspect to consider is the reduction of hospital costs when tests are made wisely. During pre-anesthetic evaluation in most patients admitted for elective surgeries, complementary tests are routinely ordered⁴ with the purpose of identifying or diagnosing diseases and disorders that may compromise the perioperative period, functional evaluation of previously diagnosed and under treatment diseases, and also help in the formulation of specific or alternative approaches for anesthetic care⁵. Routine tests are defined as compulsory tests for all patients regardless of the findings obtained from clinical evaluation^4,6. In this list, there are serum and urine biochemical changes, blood count and coagulation studies, X-ray and electrocardiogram examinations, among others⁴. However, literature data indicate that these tests are not cost- effective and neither related to any perioperative complications⁴. Published studies show no laboratory test benefit when used as the sole means of preanesthetic evaluation⁶. History and physical examination are considered the most effective methods of diagnosing disease^6,7. There is also the possibility of tests not based on clinical history leading to increased risk for the patient, especially when false-positive results motivate further research, sometimes invasive, and leading to the unnecessary postponement of surgery, prolonging hospital stay and subjecting the patient to the risk of hospital infections. It is estimated that of the US$30 billion spent in the U.S. on laboratory tests, at least 10% are intended for preoperative assessments. When taking into consideration the history and physical examination as determinants of preoperative tests, about 60-70% of laboratory tests would be unnecessary⁵. Vogt and Henson conducted a retrospective review of medical records and estimated hospital savings to be approximately US$80,000 annually just by eliminating preoperative testing not indicated for the 5,100 patients studied². Tests may be beneficial for patients who require postoperative care in the intensive care unit, as well as providing baseline values for later comparisons⁸. However, considering the lack of benefits

Table 1 Size of Surgical Procedure. and high costs, routine testing is expendable, especially in institutions in which surgical procedure must absorb the costs of laboratory tests⁸. Pzankie et al. proved that even in the elderly, routine laboratory tests were not better predictors of perioperative morbidity than ASA physical status classification and surgical risk (according to the cardiac risk criteria of the ACC/AHA)⁸. According to Miguel Garcia et al.⁹, education and training of doctors should be more scientifically sound, emphasizing the importance of effective and cost-effective clinical decisions. The financial aspects and benefits of objective tests, as opposed to extensive preoperative screening, have been thoroughly reviewed in the literature⁸. Current trends point to performing preoperative tests based on clinical assessment and careful physical examination, which, no doubt, are the bases of preanesthetic evaluation⁴.

The aim of this study was to evaluate the benefit of routine preoperative tests performed during preanesthetic evaluation of low-risk patients undergoing minor and medium elective surgeries.

Method

Prospective, cross-sectional, clinical study of a survey conducted at the preanesthetic department of Hospital Santo Antônio, Salvador, BA.

The study included 800 (eight hundred) patients of both genders, aged between 1-45 years, classified as ASA I, undergoing minor-medium elective surgeries (Table 1) at the operating theatre of Hospital Santo Antônio.

Table 2

Figure 1

Patients were attended at the preanesthetic evaluation department in the period between March and December 2009. A paper form was filled with data from laboratory tests, abnormalities in these tests, and change in approach. Change in approach was defined as new tests ordered, referral to a specialist and/or postponement of surgery. The surgeon previously ordered preoperative additional tests, according to his routine, without interference from the anesthesiologist. The results were assessed using descriptive statistics.

Results

Of the 800 patients studied, 453 (56.62%) were female and 347 (43.4%) were male. We performed 3646 preoperative tests, including complete blood count, coagulation profile, fasting glucose, urea, creatinine, sodium, potassium, electrocardiogram and chest X-ray. Of these 3646 tests, only 82 (2.25%) showed change in results, and only 14 (0.38%) required a change in approach.

Discussion

The American College of Physicians recommends that laboratory tests be ordered with selective and restrictive criteria, always supported by clinical justification. Finding changes in tests of clinically healthy patients usually does not infl uence their treatment⁶, and commonly does not alter the planning and management during the perioperative period^1,4,6. Furthermore, there is little evidence that any abnormalities found in tests compulsorily performed are associated with increased surgical morbidity. Evidence suggests that 60-70% of preoperative tests would be unnecessary if a careful clinical evaluation was performed^5-14. However, routine preoperative tests increase hospital costs and provide no protection regarding legal medicine, becoming, in this sense, an eventual extra risk for medical staff when unnecessary tests result in requests for other diagnostic procedures, which may entail risks and complications for patients^4,10. In contrast, in more than half of cases, doctors seem to ignore abnormal laboratory results, which can be more serious in terms of legal liability than not ordering the test^6. The factors infl uencing the indiscriminate ordering of preoperative tests are not well known. Some of the assumptions are insecurity during clinical evaluation, distrust of doctors in their work and literature, confidence in the fact that a larger number of exams mean more security, belief that they will have legal protection, and fear that these patients have their anesthesia postponed for lack of preoperative tests⁴.

Considering tests that are independent of each other, the greater the number of tests ordered, the greater the possibility of obtaining an abnormal result in a healthy patient ^4.13. When a preoperative test shows normal results or any abnormality with no particular clinical implication, virtually no action will be taken, and it will become a test without any utility or benefit. Currently, almost all anesthetic drugs and techniques can be handled safely for kidney and cardiovascular systems⁴. Thus, if preoperative tests are ordered with the purpose of contraindicating drugs and anesthetic techniques that could cause damage to these organs, the ordering lost its meaning⁴. Literature reports that the possibility of finding abnormal hematocrit and hemoglobin values during preoperative evaluation is very uneven, and there is no concrete evidence to confirm the hypothesis that these abnormal values increase the morbidity of these patients⁴. Likewise, renal function quantified by serum urea and creatinine during preanesthetic evaluation shows very different values, motivating no changes in anesthetic planning and perioperative period^1,4,6,12.

Recent guideline from the American College of Cardiology/American Heart Association advises that routine preoperative electrocardiogram (ECG) in asymptomatic patients undergoing low-risk operation is not useful and, in some cases, may even be harmful^1,14. Recently, Correll et al.¹⁵ published an article investigating the value of preoperative ECG and found that ECG adds no benefit in predicting postoperative cardiovascular complications, compared to the main features of medical history. The practice of indiscriminate test ordering is a problem that affects more than 30 million procedures, with a conservatively estimated direct cost above US$18 million¹⁴.

According to a systematic review by Joo et al.¹⁶, the authors concluded that the number of abnormalities observed on chest X-ray increase with age and risk factors, and that most of these changes did not alter the perioperative period or affect postoperative evolution⁵.

At Hospital Santo Antônio (OSID), most surgical clinics routinely perform hematocrit, hemoglobin, coagulation, electrocardiogram, chest X-ray, blood glucose, urea/creatinine, and sodium/potassium tests during the preoperative evaluation of most patients, regardless of physical status.

In this study, the assistant physician ordered a total of 3,646 tests from the 800 patients admitted to the anesthesia department, of which 82 were altered (2.25%), with change in approach only in 14 (0.38%). A blood count was performed in 97.62% of patients, with only 1.66% showing alterations and 0.13% requiring change in approach. Coagulation studies were ordered in 88.62% of patients, with abnormal results in 1.55% and change in approach in 1.13%. Electrocardiograms were ordered in 583 patients, with 6.86% showing alterations and only 0.51% requiring change in approach. Chest radiographs were ordered in 496 patients, with 1.21% showing alterations and none requiring change in approach. Of a total of 548 blood glucose tests ordered, only 1.82% showed abnormal results and 0.36% required change in approach. Of the 441 urea and creatinine tests, there was no change in results or approach. Of the 88 sodium and potassium tests, only 2.25% were altered and 0.38% required change in approach.

According to the Practice Advisory for Preanesthesia Evaluation -ASA Task Force, routine ECG results were documented as abnormal in 7-42.7% of cases and required change in clinical approach in 9.1% of cases. Regarding routine X-ray, results were abnormal in 2.5-60.1% of cases and change in clinical approach in 0-51%. Routine hemoglobin abnormal findings represented 0.5-43.8% of cases and requirement for change in approach represented 0-28.6%. Routine hematocrit was abnormal in 0.2-38.9% of cases and change in clinical approach in 0-100% of cases. Routine coagulation tests showing abnormalities in BT, PT, aPTT or platelet count represented 0.8-22% of cases and required change in approach in 1.1-4% of cases. Preoperative routine potassium dosages showed 1.5-12.8% of abnormal results⁹.

In preoperative routine glucose measurement in nondiabetic patients or patients with no altered glucose metabolism, abnormal glucose levels were found in 5.4-13.8% of cases. ASA Task Force agrees that preoperative tests should not be ordered routinely. In preoperative cases, it should be ordered in a selective manner with the purpose of guiding or optimizing perioperative management. The indications for such tests must be documented and based on information obtained from the results and scheduled surgical procedure complexity⁹. Unnecessary tests may cause injury to patients due to overtreatment of a false-positive or borderline result, and increase costs without reducing perioperative complications^12,13. Reducing the number of laboratory tests results thereby decreasing operating costs, time, and medical stress associated with false positive results¹².

Several studies have attempted to define the cost of unnecessary tests before elective surgery. Previous study designs have included comparison of tests ordered by surgeons with those ordered by the anesthesiologist. Em Fleicher ¹⁷, Starsnic et al.¹⁸ of Thomas Jefferson University, Philadelphia, Pennsylvania, compared the group with tests ordered by the surgeon and complemented by the anesthesiologist and vice versa, deemed necessary for two consecutive periods of time in 1992. These investigators reported an average cost saving of US$ 20.89 per patient when the anesthesiologist was the first physician determining the tests. However, there was no cancellation or changes recorded for intraoperative management attributable to inadequate testing¹⁷.

According to recent studies, the practice of anesthesiologists assessing patients and ordering tests showed a potential cost reduction of billions of dollars in preoperative testing without negatively affecting patient care ^17,19.

Therefore, we conclude that preoperative tests should not be ordered routinely and indiscriminately, but with the purpose to guide and optimize perioperative care based on clinical history, physical examination, and size of the surgical procedure. Thus, the selective ordering of these tests is a more rational conduct.

References

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Relevance of routine testing in low-risk patients undergoing minor and medium surgical procedures

Danielle de Sousa Soares^I; Roberta Ribeiro Marques Brandão^II; Mirla Rossana Nogueira Mourão^II; Vera Lucia Fernandes de Azevedo^II; Alexandre Vieira Figueiredo^II; Eliomar Santana Trindade^II

Publication Dates

• Publication in this collection
  23 Apr 2013
• Date of issue
  Apr 2013

History

• Received
  27 Feb 2012
• Accepted
  12 Apr 2012