576 CHAPTER 16 Urological surgery and equipment

Complications of surgery in general: DVT and PE

While venous thromboembolism (VTE) is uncommon after urological surgery, it is considered the most important nonsurgical complication of major urological procedures. Following TURP, 0.1–0.2% of patients experience a pulmonary embolus (PE)1 and 1–5% of patients undergoing major urological surgery experience symptomatic VTE.2

The mortality of PE is on the order of 1%.3

Risk factors for DVT and PE

Increased risk for deep venous thromboembolism (DVT) and PE is with open (versus endoscopic) procedures, malignancy, and increasing age and depends on the duration of the procedure.

Categorization of VTE risk

American College of Chest Physicians (ACCP) Guidelines on prevention of venous thromboembolism2 categorize the risk of VTE are as follows:

•Low-risk patients—those <40 years undergoing minor surgery (surgery lasting <30 minutes) and with no additional risk factors. No specific measures to prevent DVT are required in such patients other than early mobilization. Increasing age and duration of surgery increases risk of VTE.

•High-risk patients—include those undergoing non-major surgery (surgery lasting >30 minutes) who are age >60 years

Prevention of DVT and PE

See Box 16.1.

Diagnosis of DVT

Signs of DVT are nonspecific (i.e., cellulitis and DVT share common signs—low-grade fever, calf swelling and tenderness). If you suspect a DVT, arrange for a Doppler ultrasound. If the ultrasound probe can compress the popliteal and femoral veins, there is no DVT; if it can’t, there is a DVT.

Diagnosis of PE

Small PEs may be asymptomatic.

Symptoms include breathlessness, pleuritic chest pain, and hemoptysis. Signs include tachycardia, tachypnea, raised jugular venous pressure

(JVP), hypotension, and pleural rubs pleural effusion.

1 Donat R, Mancey–Jones B (2002). Incidence of thromboembolism after transurethral resection of the prostate (TURP). Scan J Urol Nephrol 36:119–123.

2 Geerts WH, Heit JA, Clagett PG, et al. (2001). Prevention of venous thromboembolism. (American College of Chest Physicians [ACCP] Guidelines on prevention of venous thromboembolism) Chest 119:132S–175S.

3 Quinlan DJ, McQuillan A, Eikelboom JW (2004). Low molecular weight heparin compared with intravenous unfractionated heparin for treatment of pulmonary embolism. Ann Intern Med 140:175–183.

COMPLICATIONS OF SURGERY IN GENERAL: DVT AND PE 577

Tests

•CXR may be normal or show linear atelectasis, dilated pulmonary artery, and small pleural effusion.

•ECG may be normal or show tachycardia, right bundle branch block, and inverted T waves in V1–V4 (evidence of right ventricular strain). The classic SI, QIII, TIII pattern is rare.

•Arterial blood gases show low PO2 and low PCO2.

•Imaging: Computed tomography pulmonary angiogram (CTPA) has superior specificity and sensitivity compared with that of ventilationperfusion (VQ) radioisotope scan.

•Spiral CT: A negative CTPA rules out a PE with similar accuracy to a normal isotope lung scan or a negative pulmonary angiogram.

Treatment of established DVT

•Below-knee DVT: above-knee thromboembolic stockings (AK-TEDs), if no peripheral arterial disease (enquire for claudication and check pulses) + unfractionated heparin (UFH) 5000 u SC 12 hourly

•Above-knee DVT: start a low molecular-weight heparin (LMWH) and warfarin, and stop heparin when INR is between 2 and 3. Continue treatment for 6 weeks for postsurgical patients; it should be lifelong if there is an underlying cause (e.g., malignancy).

•LMWH

Treatment of established PE

Fixed-dose, subcutaneous (SC) LMWH seems to be as effective as adjust- ed-dose, intravenous (IV) UFH for the treatment of PE found in conjunction with a symptomatic DVT.3 Rates of hemorrhage are similar with both forms of heparin treatment.

Start warfarin at the same time and stop heparin when INR is 2–3. Continue warfarin for 3 months.

578 CHAPTER 16 Urological surgery and equipment

Box 16.1 Options for prevention of VTE

•Early mobilization.

•Above-knee thromboembolic stockings (AK-TEDs) (provide graduated, static compression of the calves, thereby reducing venous stasis). More effective than below-knee TEDS for DVT prevention.1

•Subcutaneous heparin (low-dose unfractionated heparin [LDUH] or low molecular weight heparin [LMWH]). In unfractionated preparations, heparin molecules are polymerized, with molecular

weights from 5000 to 30,000 daltons. LMWH is depolymerized, with a molecular weight of 4000–5000 daltons.

•Intermittent pneumatic calf compression (IPC) boots, which are placed around the calves, are intermittently inflated and deflated, thereby increasing the flow of blood in calf veins.2

•For patients undergoing major urological surgery (radical prostatectomy, cystectomy, nephrectomy), AK-TEDS with IPC intraoperatively, followed by SC heparin (LDUH or LMWH) should be used. For TURP, many urologists use a combination of AK-TEDS and IPCs; relatively few use SC heparin.3

1 Howard A, et al. (2004). Randomized clinical trial of low molecular weight heparin with thighlength or knee-length antiembolism stockings for patients undergoing surgery. BJS 91:842–847. 2 Soderdahl DW, Henderson SR, Hansberry KL (1997). A comparison of intermittent pneumatic compression of the calf and whole leg in preventing deep venous thrombosis in urological surgery. J Urol 157:1774–1776.

3 Golash A, Collins PW, Kynaston HG, Jenkins BJ (2002). Venous thromboembolic prophylaxis for transurethral prostatectomy: practice among British urologists. J Roy Soc Med 95:130–131.

Further reading

British Thoracic Society guidelines for management of suspected acute pulmonary embolism (2003) Thorax 58:1–14.

Kelly J, Rudd A, Lewis RR, Hunt BJ (2002). Plasma D-dimers in the diagnosis of venous thromboembolism. Arch Intern Med 162:747–756.

Kruip MJH, Slob MJ, Schijen JH, et al. (2002). Use of a clinical decision rule in combination with D-dimer concentration in diagnostic workup of patients with suspected pulmonary embolism. Arch Intern Med 162:1631–1635.

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