In daily practice, the request for blood tests to screen hemostasis in children who are going to undergo minor or outpatient surgeries continues to be widely accepted, 10,14 being that their usefulness is low in the diagnosis of severe coagulopathies or in predicting perioperative bleeding in healthy children; on the other hand, being its indisputable usefulness in patients with anticoagulation, or patients with deficiencies in coagulation factors known preoperatively.
The clinical findings and the physical examination aimed at assessing hemostasis identified a single patient with a positive finding of suspected coagulopathy, who was later ruled out, without observing intra- or postoperative complications in the series of cases studied; Similar results were evidenced in a study with 56,000 surgeries, of which 5,120 were performed without preliminary studies and only with the regular directed clinical examination, it was evidenced that the patients could undergo anesthesia and surgery safely and with good results Intra and postoperative 6. Another study carried out in 169 adults undergoing herniorrhaphy allows us to conclude that it is rare for a standard medical history and physical examination to present perioperative bleeding, suggesting that routine preoperative tests in healthy patients are of little value9.
Despite the available evidence, the preoperative routine in many pediatric surgical centers includes a laboratory screening of hemostasis. The most requested tests are the PT, APTT and hemogram, although we also observe tests such as bleeding time and clotting time; In our study of 69 systematic studies, we observed alteration in 21% of them, mainly in LT; however, we did not observe intra- or postoperative bleeding complications, nor was a coagulation disorder diagnosed in children with altered tests. This is explained based on the findings of a meta-analysis that evaluated nine good-quality observational studies, corroborating that the coagulation tests have a positive predictive value (0.03-0.22) and a likelihood ratio (0.94- 5.1) low, indicating that they are poor predictors of bleeding, and recommending that patients with an adverse clinical history of bleeding do not require laboratory screening before surgery2.
The study also provides information on the tests requested arbitrarily (not routine) and on some measures taken into account to correct any altered result in the routine tests; We observed that 149 tests (out of 218 tests) were requested non-routine and without clinical justification, without providing benefit in terms of clinical or surgical management; Similar results are analyzed in 2 studies in 520 patients submitted to non-cardiac surgeries, in which it is concluded that routine examinations are neither functional nor cost-effective, recommending that they be requested only based on concomitant diseases, type of surgery to perform 5.7.
Something not described in similar literature is the practice of correcting values ​​of some altered complimentary exam, without corroborating with the clinic, a practice identified in 18% of the patients and that includes repeating and confirming the altered study to the transfusion of blood products, situation incredibly striking, because it could not only be considered useless and not cost-effective but also risky due to the eventual complications of blood derivatives transfusion, which in these cases far outweigh the benefits; For the study, no follow-up was carried out on the transfused patients, however, none of them presented complications during their hospital stay.
The benefit of a laboratory screening for coagulation disorders with the tests is low, mainly due to its low sensitivity and specificity and low positive predictive value and likelihood ratio2, in addition to this mentioning that coagulation disorders are rare diseases. Frequent; In the HNMAV in 2018, out of 55,000 patients attended, 2 cases of hemophilia were diagnosed per year, mainly due to symptoms; no other coagulopathies were diagnosed in that year.
Patient charges amounted to Bs 47 per patient on a routine basis, and Bs 255 per patient for charges associated with non-routine tests or for the correction of altered values ​​in 15 patients; Therefore, on average, a cost in preoperative laboratory tests of approximately 102 Bs per patient is incurred.
If laboratory tests for all outpatients for surgery or minor procedures had been ordered based on the findings of the medical history and physical examination of the patient rather than by standard or arbitrary criteria, in 69 patients studied only the laboratory tests in 1 case; so new This hospital could potentially have reduced patient costs by more than 7,000 Bs. in the study group, and it can be inferred that during one year it can be reduced between 32,100 Bs. to 187,000 Bs, without adverse results expected.
In conclusion, the study established that routine preoperative screening tests are of little use and little cost-benefit in assessing hemostasis for minor or outpatient procedures, compared to clinical history and directed physical examination; its indication being appropriate when there are abnormal findings in the physical examination and clinical history or based on concomitant diseases; Additional multicenter studies are required16 to extend the recommendations to other cities with the same geographic, sea-level and sociodemographic characteristics of our country, seeking to guide medical behaviours to be more efficient with the use of resources, in a context of limited resources.
What can I do to lower my blood prothrombin time?
If you have high prothrombin time values, you can follow the following tips:
Increase in the consumption of vitamin K in case it was due to a nutritional deficiency. Foods rich in vitamin K are cauliflower, spinach, broccoli, asparagus, avocado, Brussels sprouts, chickpeas, lettuce, spinach and chard.
Avoid alcohol consumption as it may damage the liver and make it difficult to form the proteins necessary for the clotting process.Prothrombin time (PT)
Prothrombin time (PT) is the primary measurement used in the control of oral anticoagulant treatment. Prolongation of PT depends on reductions in three of the vitamin K-dependent clotting factors (II, VII, and IX). The changes observed in PT during the first days of treatment with warfarin/acenocoumarol are mainly due to reductions in factors VII and IX, which have the shortest half-lives (6 and 24 hours, respectively).
Both venous blood and capillary blood can be used to control anticoagulant treatment.
To obtain a result, thromboplastin is added to the blood sample to activate clotting. This causes a blood clot to form. The time it takes for the clot to form is measured in seconds, known as the prothrombin time.
In some countries, blood coagulability is generally expressed in a unit called the Quick value. In this case, the measured prothrombin time is expressed relative to the clotting time of a healthy person. The value obtained is the “percentage of the reference value.” The “normal” Quick value is between 70 – 100% in a person not receiving oral anticoagulants.
A Quick value of only 30%, for example, indicates that the blood clotting time is longer than average.
The longer the patient’s clotting time, the lower the Quick value.
