Hematologic Problems

Hematologic Problems

Hereditary coagulopnthies. Patients with inherited bleeding disorders are usually aware of their problem, allowing the clinician to take the necessary precautions before any surgical procedure. However; in many patients, prolonged bleeding after the extraction of a tooth  maybe the first evidence that a bleeding disorder exists. Therefore all patients should be questioned concerning coagulation after previous injuries and surgery.  A
history of epistaxis (nosebleeds), easy bruising, herna- turia, heavy menstrual bleeding, and spontaneous bleeding should alert the dentist to the possible need for a presurgical laboratory coagulation screening. A PT is used to test the extrinsic pathway factors (II, V, VII, and X), .
whereas a PTT is used to detect intrinsic pathway factors. To better standardize PT values within and between hospitals, the International Normalized Ratio (\NR) method has been developed. This technique adjusts the actual PT for variations in agents used to run the test, and the value is presented as a ratio between the patient’s’ I’T and a standardized
value from the same laboratory.

Platelet inadequacy usually causes easy bruising and is evaluated by a bleeding time and platelet count. If a coagulopathy is suspected, the primary care physician or a hematologist should be consulted about more refined testing to better define the cause of the bleeding disorder and
to help manage the-patient in the preoperative period.

The management of patients with coagulopathies who require oral surgery depends on the nature of the bleeding disorder. Specific factor deficiencies, such as hemophilia A, B, or C, or von willebrand’s disease, are usually managed  by the preopcrative administration of factor replace merit and by the use of an antibrinolytic agent, such as a ninocaproic acid (Amicar). The physician decides the form in which factor replacement is given, based on the’ degree of factor deficiency and on the patient’s history of factor replacement. Patients who receive factor replace merit sometimes contract hepatitis or the human irnrnurrodeficiency virus (HIV]. Therefore appropriate staff protection measures should be taken during surgery.

Platelet problems may be quantitative or qualitative. Ouantitative platelet deficiency may be a cyclic problem, and the hematalogist can help determine the proper timing of elective surgery. Patients with a chronically low platelet count can he give platelet transfusions.
Counts usually dip below 50.000 before abnormal postoperative
bleeding occurs. If the platelet count i~ between 20,000 and 5O,OOO, the hematologist- may wish to withhold platelet transfusion until  ostoperative
bleeding becomes :I problem. However, platelet transfusions may be given to patients with counts higher than 50,000 if a qualitative platelet problem, exists. Platelet counts under 20,000 usually require presurgical platelet transfusion or a delay in surgery until platelet numbers ris-e. Local anesthesia should be given by local infiltration rather than by field blocks to lessen the likelihood of damaging larger blood vessels, which can lead to prolonged postinjection bleeding and hematoma formation. Consideration should be given to the use of topical coagulation-promoting substances in oral wounds, and· the patient should be carefully instructed in ways to
avoid dislodging blood clots once they have formed (Box 1-22). .

Therapeutic anticoagulation. Therapeutic anticoagulation is administered to patients with thrombogenic implanted devices, such as prosthetic heart valves; with thrombogenic cardiovascular problems, such as atrial fibrillation or post-Ml: or with a need for extra corporeal blood flow, such as for hemodialysis. Patients may also take drugs with anticoagulant  properties, such as aspirin, as a secondary effect.

When elective oral surgery is necessary, the need for continuous anticoagulation must be weighed against the need for blood clotting after surgery. This decision should be made in consultation with the patient’s primary care physician. Drugs such as aspirin do not usually need to be
withdrawn to allow routine. surgery. Patients on heparin usually can have their surgery delayed until the circulating heparin is inactive (6 hours if heparin is given IV, 24 hours if given subcutaneously [SC)). Protamine sulfate, which reverses the effects of heparin, can also be used if emergency oral surgery cannot be deferred until heparin is naturally inactivated.

Patients requiring warfarin for anticoagulation but who also need elective oral surgery benefit from close operation between the patient’s physician and dentist. Warfarin has a’ 2- to ‘3-day delay in the onset of action
therefore alterations of ‘warfarin anticoagulant effects appear several days after the dose is changed. The 1’T is- ‘used to gauge the anticoagulant action of warfarin. xtost physicians allow the PT to drop to 1.5 1:\’1{ during the
preoperativc period, which usually 3110\\’5 sufficient coagulation for sate surgery. Patients should stop taking warfarin 2 or  before the planned surgery. On the morning of surgery, the I’T should be checked; if it is between 1.5 and 2 INR, surgery can be performed. If the PT is still greater than 2 I:'<H. ,uJ.~ery should he delayed until the PT approaches I.S I:\IL Surgical wounds should be dressed wit h thrombogenic substances, and the
patient should be given instructiou in promoting dot retention. Warfarin therapy (an be resumed tile day. Surgery (Box -23).

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