Wide tourniquets eliminate blood flow at low inflation pressures.

Previous recommendations for use of pneumatic tourniquets in extremity surgery suggest parameters for maximum pressure and time limits without regard for optimum cuff width. Wide cuffs produce lower readings of blood pressure relative to narrow cuffs, presumably because the wide cuffs arrest flow at lower inflation pressure. We investigated three tourniquet sizes and the inflation pressure required to eliminate flow to the upper extremity using an ultrasonic Doppler device to monitor blood flow in the radial artery of ten normal subjects (arm circumference 24.

Gravitational haemodynamics and oedema prevention in the giraffe.

Because it is so tall, the giraffe, Giraffa camelopardalis, provides an important animal model for investigating adaptive mechanisms to orthostatic (gravitational) pressure changes. Previous physiological studies of the giraffe have concentrated on arterial blood pressures in the heart and neck. Briefly, these investigations revealed that arterial pressure near the giraffe heart is about twice that in humans, to provide more normal blood pressure and perfusion to the brain.

Management of chronic exertional anterior compartment syndrome of the lower extremity.

Eighteen patients (28 compartments) with chronic exertional compartment syndrome and 14 normal asymptomatic volunteers (18 compartments) were studied. Evaluation included clinical assessment followed by quantitative determination of intracompartmental pressures as monitored by wick or slit catheters before and after exercise. Intramuscular pressures measuring greater than or equal to 10 mmHg at rest and/or greater than or equal to 25 mmHg five minutes after exercise were defined as abnormally elevated.

Increased transsynovial transport with continuous passive motion.

Thirteen freshly killed immature rabbits were used to study the effect of continuous passive motion (CPM) on regional nutritional pathways of the medial and lateral menisci and the transport of a solute from synovial fluid to the patellar tendon. A bolus of 35SO4 was injected into each knee joint cavity. The right knee underwent CPM for 1 h, whereas the left knee was immobilized (rest extremity).

Local compression patterns beneath pneumatic tourniquets applied to arms and thighs of human cadavera.

Distributions of tissue fluid pressure were examined beneath a standard pneumatic tourniquet in six upper extremities and six lower extremities of fresh human cadavera, disarticulated at the shoulder and hip, respectively. A standard 8-cm-wide tourniquet cuff was applied at mid-humerus or mid-femur position. Tissue fluid pressures were measured by 100-cm-long slit catheters inserted parallel to the bone at four tissue depths: subcutaneous, subfascial, mid-muscle, and adjacent to bone.

Compartment syndrome of the thigh complicating surgical treatment of ipsilateral femur and ankle fractures.

A 26-year-old man presented with ipsilateral femur and ankle fractures. The patient was treated with interlocking nail of his femur fracture, followed by open reduction and internal fixation of his ankle fracture under tourniquet control. Postoperatively, the patient developed compartment syndrome of his thigh with elevated pressures, requiring decompressive fasciotomies.

Muscle soreness and intramuscular fluid pressure: comparison between eccentric and concentric load.

This study investigates the dynamic and resting intramuscular pressures associated with eccentric and concentric exercise of muscles in a low-compliance compartment. The left and righ leg anterior compartments of eight healthy males (ages 22-32 yr) were exercised by either concentric or eccentric contractions of the same load (400 submaximal contractions at constant rate, 20/min for 20 min at a load corresponding to 15% of individual maximal dorsiflexion torque). Tissue fluid pressures were measured with the slit-catheter technique before, during, and after the exercise.

Hyperbaric oxygen reduces edema and necrosis of skeletal muscle in compartment syndromes associated with hemorrhagic hypotension.

This study examined the effect of exposures to hyperbaric oxygen on the development of the edema and necrosis of muscle that are associated with compartment syndromes that are complicated by hemorrhagic hypotension. A compartment syndrome (twenty millimeters of mercury for six hours) was induced by infusion of autologous plasma in the anterolateral compartment of the left hind limb of seven anesthetized dogs while the mean arterial blood pressure was maintained at sixty-five millimeters of mercury after 30 per cent loss of blood volume. These dogs were treated with hyperbaric oxygen (two atmospheres of pure oxygen) and were compared with six dogs that had an identical compartment syndrome and hypotensive condition but were not exposed to hyperbaric oxygen.

Intervertebral disc nutrition. Diffusion versus convection.

Nutrient diffusion across the vertebral endplate can occur by convection (bulk flow) or diffusion. Previous studies, using animal models, suggested diffusion as the primary mechanism of small-solute transport but did not adequately determine the contribution of bulk flow to total nutrient transport. This study was designed to reevaluate disc nutrition across the endplate.

Real-time acquisition and data analysis of skeletal muscle contraction in a multi-user environment.

A data acquisition system is described which acquires data from contracting skeletal muscle. The system is designed to run in a multi-user environment while acquiring contractile data in real-time. Time dedicated solely to laboratory experiments is thus eliminated.

Long-term effects of spinal cord transection on fast and slow rat skeletal muscle. I. Contractile properties.

Contractile properties of rat soleus and extensor digitorum longus muscles were studied 1 year after complete thoracic spinal cord transection (spinal cord level T9). Force-generating capacity and contraction speed were unchanged in the extensor digitorum longus 1 year after transection. However, the rate of contraction and relaxation increased in the soleus as reflected by a decrease in time-to-peak tension and increase in fusion frequency.

Long-term effects of spinal cord transection on fast and slow rat skeletal muscle. II. Morphometric properties.

Morphometric properties of rat soleus and extensor digitorum longus muscles were studied 1 year following complete thoracic spinal cord transection (spinal cord level T9). Both muscles demonstrated almost complete type 1 to type 2 muscle fiber type conversion after 1 year. Muscle fiber atrophy was observed in both muscles.

Delayed use of hyperbaric oxygen for treatment of a model anterior compartment syndrome.

This study examines the effect of delayed exposure to hyperbaric oxygen on muscle necrosis and edema development following compartment syndromes in the canine hindlimb. Compartment syndromes (100 mm Hg for 8 h) were generated in one anterolateral compartment of six anesthetized dogs. After a 2-h delay, three 1-h hyperbaric oxygen treatments (2 atm absolute pure oxygen) were given during the next 12 h.

Nutrition of the anterior cruciate ligament. Effects of continuous passive motion.

Twelve freshly killed mature male rabbits were used to study the effects of continuous passive motion (CPM) on regional and overall nonvascular nutritional pathways of the anterior cruciate ligament (ACL). One hundred fifty microcuries of 35sulphate was injected intraarticularly into each knee joint. The right knee underwent CPM for 1 hour, while the left knee remained immobilized.

Decompression of an experimental compartment syndrome in dogs with hyaluronidase.

The treatment of compartment syndromes in which elevation of intracompartmental pressure occurs is by surgical fasciotomy. This is a relatively simple procedure but may be associated with complications. This study aimed at developing an alternative method to decompress a compartment by use of the enzyme hyaluronidase.

Long-term myoneural function after an induced compartment syndrome in the canine hindlimb.

For evaluation of long-term myoneural function in a compartment syndrome model of the canine hindlimb, five conditioned dogs had injections of autologous plasma into the hindlimb anterolateral muscle compartment, maintaining the pressure at 40 mmHg for eight hours. A newly described technique for measuring muscle function was used before pressurization and at weekly intervals following pressurization for a period of one month. Two days after pressurization, isometric twitch torque and tetanic torque showed a significant decrease (p less than .

The effect of antivenin on intramuscular pressure elevations induced by rattlesnake venom.

The dose of an antivenin required to neutralize a clinical case of venom poisoning, as well as determining the timing or need to initiate antivenin treatment, is frequently difficult to objectively ascertain. In this study, venom from the southern Pacific rattlesnake, Crotalus viridis helleri, was injected into 29 dog hind limb anterolateral compartments. A solution of C.

Ankle and knee position as a factor modifying intracompartmental pressure in the human leg.

The objective of this study was to examine the effect of position of the knee and ankle on intracompartmental pressures in the leg. Slit catheters were introduced bilaterally into all four muscle compartments of the lower extremities of six healthy volunteers. Intracompartmental pressures were monitored with the catheters while the ankle joint was passively held in full dorsiflexion, full plantar flexion, or neutral with the knee flexed 90 or 10 degrees or fully extended.

Intramuscular fluid pressure during isometric contraction of human skeletal muscle.

Intramuscular fluid pressures were recorded in the vastus medialis of seven healthy male volunteers. Pressures were measured simultaneously at three different sites in the muscle by a catheter-tip transducer with extremely low volume-displacement characteristics and by two extracorporeal transducers connected to slit catheters. All three recording systems gave qualitatively similar results provided the catheters had inner diameters exceeding 0.

Rattlesnake bites and surgical decompression: results using a laboratory model.

Studies were performed on the hind limbs of dogs and their anterolateral compartments to evaluate the effect of fasciotomy on tissue pressure and necrosis following pit viper envenomation. Venom from the southern Pacific rattlesnake, Crotalus viridis helleri, was injected into either the subcutaneous tissues, the intact anterolateral compartment or the anterolateral compartment following fasciectomy. Interstitial fluid pressure measurements, as well as limb girth and surface temperatures, were obtained over the first 48 hr following venom injection, after which time the compartment contents were examined microscopically.