Background
Venous thromboembolism (VTE), presenting as deep venous thrombosis (DVT) or pulmonary embolism (PE), is a common complication after major joint surgery such as total hip replacement (THR). This occurs because of a combination of patient-specific predisposing factors and factors associated with the surgical procedure itself including release of thromboplastins in response to the insertion of instruments into the medullary canal for implanting the prosthetic components, reduction in venous blood flow associated with limb position during the procedure, and postoperative immobility.
Preventative measures commonly used in patients undergoing THR include prophylactic anticoagulation and mechanical methods such as intermittent pneumatic compression (IPC) devices, or a combination of both. Intermittent pneumatic compression devices have several advantages over prophylactic anticoagulation therapy in that they are generally well-tolerated by patients and do not increase the risk of bleeding, which is particularly useful when anticoagulation is contraindicated. When applied to the foot, calf, or whole leg, IPC devices decrease venous stasis and improve blood flow velocity by mimicking the natural activity of the calf muscle through intermittent cycles of compressed air, which alternately inflate and deflate the air bladders within cuffs.
A wide range of IPC devices are available that offer variation in the length and location of the sleeve and the bladder, the frequency and duration of activation, the rate at which the pressure increases, the maximum pressure that is achieved, and whether the compression is simultaneous or sequential. It is therefore important to evaluate the effectiveness of different IPC devices for prophylaxis against VTE after THR in order to inform clinical decision making.
Objectives
To assess the comparative effectiveness and safety of different IPC devices with respect to the prevention of VTE in patients after THR.
Interventions/Methods
This review (Zhao et al., 2014) was an update of a previous review (Zhao et al., 2012) that included randomized controlled trials (RCTs) and quasi-randomized designs that compared different IPC programs used in patients after THR for the prevention of VTE. Participants included patients 18 years and older who had undergone THR with or without concomitant use of other types of thromboprophylactic measures together with IPC devices. Included IPC program interventions differed in terms of type of compression garment, location of air bladder, pattern of pump pressure cycles, compression profiles and cycle length, duration of inflation time, or different cycling models such as automatic cycling devices.
Primary outcome measures included the following:
* Symptomatic VTE
* Symptomatic proximal and distal DVT (fatal and nonfatal) venographically or sonographically diagnosed
* Symptomatic nonfatal PE diagnosed by ventilation- perfusion (V/Q) lung scan, spiral computed tomography, or pulmonary angiography
* Death related to embolic event (fatal PE)
* Imaging-diagnosed asymptomatic VTE
Results
One quasi-randomized trial met the inclusion criteria, which was the same study identified in the previous review. A total of 121 participants (n = 18 males, n = 103 females) from a single center who had undergone THR were allocated to either the calf-thigh pump intervention group (n = 58, mean age = 61 years) or the plantar pump intervention group (n = 63, mean age = 62 years). All participants were fitted with the IPC devices immediately after the THR operation for the duration of 4 hours per day over a period of 21 days.
Thrombogenesis was measured using the D-dimer level before and after THR, and the patient's postoperative swelling was measured by the thigh and lower leg circumferences at 6 a.m. on the day of the operation and again at the same time on Days 3, 7, 14, and 21 postoperatively. The postoperative measurement values were then compared with the preoperative measurements (taken as 100%) to evaluate the patient's postoperative swelling.
Results of this review demonstrated no cases of symptomatic DVT or PE in either the calf-thigh compression device group or the plantar compression device group during the first 3 weeks after THR. The calf-thigh pneumatic compression device was more effective than plantar compression device for reducing thigh swelling during the early postoperative stage. No deaths related to embolic event occurred during the trial period, and imaging-diagnosed asymptomatic VTE was not assessed.
Conclusions
The authors conclude that there is insufficient evidence to make an informed choice of IPC device for VTE following THR. They suggest that there is an urgent need for further multicenter RCTs that include a sufficient number of participants and that measure clinically relevant outcomes such as mortality, imaging-diagnosed asymptomatic VTE, and major complications.
Implications for Practice
On the basis of these inconclusive results and until sufficient good quality evidence is available, it is perhaps more important for nurses to focus on ensuring that whichever IPC device is being used for patients post-THR, that it is patient-centered taking into account the risk-benefit ratio, that the device is applied correctly, and that patient compliance is appropriately monitored.
References