Intermittent External Compression Research Articles

The Acute Impact of External Compression on Back Squat Performance in Competitive Athletes.

The aim of the present study was to evaluate the effects of external compression with blood flow restriction on power output and bar velocity changes during the back-squat exercise (SQ). The study included 10 judo athletes (age = 28.4 ± 5.8 years; body mass = 81.3 ± 13.1 kg; SQ one-repetition maximum (1-RM) 152 ± 34 kg; training experience 10.7 ± 2.3 years). Methods: The experiment was performed following a randomized crossover design, where each participant performed three different exercise protocols: (1) control, without external compression (CONT); (2) intermittent external compression with pressure of 100% arterial occlusion pressure (AOP) (EC-100); and (3) intermittent external compression with pressure of 150% AOP (EC-150). To assess the differences between conditions, the participants performed 3 sets of 3 repetitions of the SQ at 70% 1-RM. The differences in peak power output (PP), mean power output (MP), peak bar velocity (PV), and mean bar velocity (MV) between the three conditions were examined using repeated measures two-way ANOVA. Results: The post hoc analysis for the main effect of conditions showed a significant increase in PP (p = 0.03), PV (p = 0.02), MP (p = 0.04), and MV (p = 0.03), for the EC-150, compared to the CONT. Furthermore, a statistically significant increase in PP (p = 0.04), PV (p = 0.03), MP (p = 0.02), and MV (p = 0.01) were observed for the EC-150 compared to EC-100. There were no significant changes in PP, PV, MP, and MV, between EC-100 and CONT conditions. Conclusion: The results indicate that the use of extremely high-pressure external compression (150% AOP) during high-loaded (70% 1-RM) lower limb resistance exercise elicits an acute increase in power output and bar velocity.

Surgical Unroofing for Anomalous Aortic Origin of Coronary Arteries

Anomalous aortic origin of a coronary artery (AAOCA) from an opposite sinus of Valsalva is an uncommon congenital defect that is typically only discovered on cardiac catheterization or on autopsy following sudden cardiac death. Conjectured mechanisms for the ischemia are generally believed to relate to the unique and easily obstructed geometry of the coronary ostium and the stenotic intramural coronary segment. Given the potentially devastating consequences of not repairing an AAOCA—that is, sudden cardiac death—these patients should undergo repair of the anomaly when it is discovered. Multiple options for surgically correcting the AAOCA have been developed, and the most used approaches include coronary artery bypass grafting, coronary reimplantation, and unroofing of the intramural segment. Here we present the technique for surgical unroofing of the intramural segment of an anomalous coronary artery of aortic origin.

Assisted Fontan procedure: animal and in vitro models and computational fluid dynamics study☆☆☆

Fontan connection with intermittent compression by wrapped latissimus dorsi (LD) was tested in vivo, in vitro and by means of computational fluid dynamics (CFD). Experimental study: LD was conditioned in four pigs for three weeks before Fontan connection by valved conduit wrapped with LD. Mock circuit: Inflatable cuff wrapped around valved conduit provided intermittent external compression, with pressure and flow measured at driving pressure of 8 or 16 mmHg. CFD study: A circuit was tested for possible increase above basal flow (4 l/min) with intermittent external compression. Experimental study: Intermittent conduit compression by LD provided mean 7% decrease of baseline PA pressure, with simultaneous flow increase of 2%. Mock circuit: By raising the driving pressure from 8 to 16 mmHg, the flow increased with baseline PVR (56%) and with elevated PVR (80%). Total pulmonary flow was reduced during intermittent external compression with both baseline and elevated PVR. CFD study: Compression with 13.0 mmHg provided 4.9% increase of total pulmonary flow with substantial increase of the peak flow (92%). In vivo and in vitro, the increased flow produced by compressing a conduit was confounded by the inevitable intermittent flow restriction. Mathematical model using lower pressure for intermittent external compression showed potential for increase in pulmonary flow.

Severe leg compartment syndrome associated with dorsal lithotomy position during radical hysterectomy

We encountered a female patient with left-leg compartment syndrome; a devastating complication, probably associated with prolonged dorsal lithotomy position during radical hysterectomy using intermittent pneumatic compression. This patient was intensively treated and fortunately recovered. However, leg compartment syndrome is poorly understood by gynecologists. We must always consider the potential risk of this life-threatening complication when patients are placed in the dorsal lithotomy position for a prolonged period during extended surgery using intermittent external compression.

Pediatric Median Neuropathy Due to Pruritus in Alagille Syndrome

Median entrapment neuropathy or carpal tunnel syndrome is uncommon in children. The majority of cases are related to genetic conditions which result in skeletal dysplasia or altered connective tissue characteristics, direct injury to the median nerve caused by intensive sports or trauma, or hereditary neuropathy with liability to pressure palsies. This report describes a 10-year-old patient with Alagille syndrome who presented with poor fine motor skills because of an entrapment neuropathy of the median nerve at the wrist. This condition was probably caused by intermittent external compression at the wrists due to years of rubbing both wrists and hands to relieve pruritus. To our knowledge, median neuropathy has never been associated with Alagille syndrome, although severe pruritus is considered a major symptom and many patients exhibit widespread scratching and rubbing.

Effects of lithotomy position and external compression on lower leg muscle compartment pressure.

Case reports have suggested that externally applied pressure from antithrombosis devices may contribute to the development of compartment syndromes during extended surgery in the lithotomy position. The purpose of this study was to assess the effects of a pneumatic compression device on directly measured intracompartment pressure in the lower leg with the leg positioned in the lithotomy position. In 25 conscious, healthy men and women, the authors measured pressure within the tibialis anterior muscle compartment with the leg supine and in the lithotomy position with and without intermittent compression. Three different devices were used to keep the leg in the lithotomy position, supporting the leg either behind the knee, under the calf, or at the ankle. The lithotomy position with support behind the calf or knee increased intracompartment pressure to 16.5+/-3.4 versus 10.7+/-5.8 mmHg supine (mean +/- SD; P < 0.05). The addition of intermittent compression decreased pressure to 13.4+/-5.1 mmHg during lithotomy (P < 0.05) and to 9.1+/-7.0 mmHg in the supine position (P < 0.05). In contrast, the lithotomy position with support near the ankle decreased intracompartment pressure to 8.7+/-5.6 versus 13.3+/-5.1 mmHg supine (P < 0.05). The addition of intermittent compression decreased pressure to 6.5+/-5.4 mmHg during lithotomy (P < 0.05) and to 10.3+/-4.7 mmHg in the supine position (P < 0.05). These results show that the lithotomy position is associated with changes in intracompartment pressure that are dependent on the method of leg support used. Furthermore, they indicate that intermittent external compression can reduce intracompartment pressure in the lower leg. Therefore, increases in intracompartment pressure during surgery in the lithotomy position with the calf or knee supported may be one of the factors that contribute to the development of compartment syndrome. Further, use of intermittent external compression may significantly reduce this pressure increase.

Editorial: Intracoronary adenovirus-mediated transfer of immunosuppressive cytokine genes prolongs allograft survival

Editorial: Intracoronary adenovirus-mediated transfer of immunosuppressive cytokine genes prolongs allograft survival

Use of a venous assist device after repair of complex lesions of the right heart

Sixteen patients underwent hemodynamic evaluation of a venous assist device after complex operations on the right side of the heart. The device consists of an inflatable abdominal binder attached to a Jobst extremity pump causing intermittent external compression of the abdomen. In addition, six of these patients were evaluated using total lower body compression for comparison. Modifications of the Fontan procedure were performed in 14 patients, mitral valve anuloplasty and tricuspid valve replacement in 1 patient and reconstruction of the right ventricular outflow tract for treatment of pulmonary atresia with intact septum in 1 patient. The patients' ages ranged from 23 months to 31 years (mean 10.7 +/- 1.8 years). Systemic blood pressure, right and left atrial pressures, heart rate and arterial-mixed venous oxygen saturation difference were recorded in each patient with and without the device in place. With the venous assist device, mean systolic pressure increased from 95 +/- 4 to 122 +/- 3 mm Hg (p less than 0.05) and diastolic pressure rose from 57 +/- 3 to 70 +/- 3 mm Hg (p less than 0.05). Left atrial pressure increased from 7 +/- 1 to 15 +/- 1 mm Hg and right atrial pressure from 15 +/- 1 to 23 +/- 1 mm Hg (both p less than 0.05). In addition, arterial-mixed venous oxygen saturation difference decreased from 29% without the device to 23% with the device in place (p less than 0.05). Total lower body compression gave similar results to intermittent abdominal compression alone.(ABSTRACT TRUNCATED AT 250 WORDS)

External compression for the prevention of scar capsule contracture--a preliminary report.

One of the many methods that have been suggested for the prevention of capsule contracture is the use of capsule expansion exercises. However, the effectiveness of such treatment has remained controversial and has never been studied in a controlled manner. An experiment was designed to study the effect of intermittent external compression on gel implants in dogs. In adult mongrel dogs 200 cc gel implants were placed subcutaneously on either side of the chest wall. Postoperatively, the dogs were treated with an inflation panel which was held over one implant by a canvas jacket. The other implant served as a control. The implants were evaluated by both applanation and indention tonometry. Treatment continued for three months and the dogs were followed for an additional twelve months postoperatively. Of the original 5 dogs, 2 failed to develop contracture on either side. The remaining 3 developed varying degrees of contracture which was in all cases more severe on the control side. In the twelve months of subsequent follow-up, 2 of these dogs remained soft on the treated side and firm on the control side.