Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Decompression”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed2006

Microdebrider decompression of schwannoma: a novel method of excising a neck mass.

OBJECTIVE: This case report describes the excision of a large neck neurofibroma causing compression of the esophagus and airway in a young patient with neurofibromatosis type 2 (NF2). At the conclusion of this article, readers should be able to describe a novel method of excising large encapsulated neck masses using microdebridement for decompression. The safety and efficacy of this method is discussed. STUDY DESIGN: The subject of this report was a 26-year-old woman with NF2. She presented with an enlarging right neck mass extending from the mandible to the clavicle that was compressing both her airway and esophagus. Given her auditory brainstem implant, unipolar cautery was contraindicated. Therefore, it was planned to decompress the patient's neck mass using a microdebrider before attempting to fully dissect out the mass. METHODS: The neck mass was exposed and then entered. Using a Xomed XPS microdebrider (Medtronic Inc., Minneapolis, MN), the mass was debrided and debulked in all directions taking care not to violate the capsule. After this, the entire capsule was dissected out using only bipolar cautery and suture ligatures for hemostasis. RESULTS: Microdebrider decompression of the neck neurofibroma allowed for preservation of the capsule without injuring vital structures in the neck. Postoperatively, the patient's swallowing and laryngeal function improved markedly. CONCLUSION: Microdebrider debulking before dissection of the patient's large neck mass safely relieved compression of the airway and esophagus. This method may be applied to other large benign masses in the neck as well.

Adult↗
PubMed2003

Percutaneous left ventricular "vent" insertion for left heart decompression during extracorporeal membrane oxygenation.

OBJECTIVE: Description of a novel method of left ventricular decompression by a percutaneous technique under transthoracic echocardiographic guidance. DESIGN: Case report. SETTING: Supraregional cardiac referral center. PATIENT: PATIENT with end-stage cardiomyopathy. INTERVENTIONS: Percutaneous insertion of a modified Mullins transseptal sheath under transthoracic echocardiographic guidance. MEASUREMENTS AND MAIN RESULTS: Successful decompression of the left ventricle and subsequent orthotopic heart transplantation. CONCLUSIONS: In patients at high risk of bleeding, a percutaneous technique may be useful for left ventricular decompression.

Adolescent↗
PubMed2003

Effect of various nerve decompression procedures on the functions of distal limbs in streptozotocin-induced diabetic rats: further optimism in diabetic neuropathy.

It is known that diabetic neuropathy is the result of endoneurial edema caused by various biochemical reactions triggered by hyperglycemia. This sequence of events can cause cessation of circulation at the perineurial level, or the tough layer, which is not resilient enough to spread intraneural pressure. Internal and external limiting structures create a double crush phenomenon to the nerve structure. Decompression of the nerve trunk at separate levels is one of the adjuncts to the overall treatment plan for diabetic neuropathy. In this study, the right sciatic nerves of 30 rats with streptozotocin-induced diabetes were used; three groups were created. In the control group, the sciatic nerves were explored and dissected only. In group II, tarsal tunnel release was performed and accompanied by epineurotomy of the sciatic nerve and its peroneal and tibial extensions. In group III, in addition to the procedures performed in group II, perineural sheaths, exposed through the epineurotomy sites at both the peroneal and tibial nerves, were incised for decompression of the fascicles. Improvement in diabetic neuropathy was evaluated by using footprint parameters. The last print length values, estimated according to the 38-month measurements, were 26.1 +/- 0.12 mm in the control group, 23.2 +/- 0.07 mm in group II, and 22.2 +/- 0.1 mm in group III. The toe spread and intermediate toe spread values of the groups were parallel to improvements in print lengths throughout the study. The best improvement was observed in the perineurotomy group. Finally, an electron microscopic study revealed variable degenerative changes in all groups, but they were milder in groups II and III. This experimental study reveals that adding internal decompression to external release doubled the effect in reducing derangement in the sciatic nerves of the rats and, in the authors' opinion, offers cause for further optimism in the treatment of diabetic neuropathy.

Animals↗
PubMed2005

Surgical or medical decompression as a first-line treatment of optic neuropathy in Graves' ophthalmopathy? A randomized controlled trial.

OBJECTIVE: Only a small percentage of Graves' ophthalmopathy (GO) patients develop optic neuropathy with impending loss of visual acuity. Therapy with methylprednisolone pulses is the treatment of first choice in severe and active GO patients. When the effect is insufficient, patients are usually treated with surgical decompression. We investigated whether surgery could become the first-line treatment, thus preventing treatment with steroids. DESIGN AND SUBJECTS: We performed a randomized trial in 15 patients with very active GO and optic neuropathy. Six patients were treated with surgical decompression, and nine with methylprednisolone i.v. pulses for 2 weeks, followed by oral prednisone for 4 months. The primary outcome was determined by changes in visual acuity. If the eye disease deteriorated despite treatment or did not improve sufficiently, patients were switched to the other treatment arm. RESULTS: The severity and activity of GO in both groups were similar at baseline. The Clinical Activity Score (CAS) was 6.3+/- 0.8 in the surgical group vs. 6.0+/- 0.5 in the steroids group and the Total Eye Score was 24+/- 6 vs. 25+/- 6. In the surgery group, 5/6 patients (82%) did not respond because of insufficient improvement in vision (n=3) or persistent chemosis (n=2), and all needed further immunosuppression. In the steroids group, 4/9 patients (45%) did not improve in visual acuity (P=0.132 vs. surgery group), and these needed decompressive surgery. All patients in whom therapy failed were switched to the other treatment arm and visual acuity improved in almost all patients. Visual acuity improved from 0.36 (0.02--0.40) to 0.90 (0.63--1.0) in the surgery group and from 0.50 (0.32--0.63) to 0.75 (0.32--1.0) in the steroids group at 52 weeks. At long-term follow-up in the surgery group 3/6 patients required squint surgery and 5/9 patients in the steroids group. Eyelid surgery was performed in 5/6 patients in the surgery group and in 4/9 patients in the steroids group. CONCLUSION: Immediate surgery does not result in a better outcome and therefore methylprednisolone pulse therapy appears to be the first-choice therapy.

Acute Disease↗
PubMed1962

Rupture of bacteria by explosive decompression.

Foster, John W. (University of Georgia, Athens), Robert M. Cowan, and Ted A. Maag. Rupture of bacteria by explosive decompression. J. Bacteriol. 83:330-334. 1962.-A device is described for instantaneously rupturing bacteria and other cells in a closed system under controlled conditions by explosive decompression. With this device, 31 to 59% of Serratia marcescens, ranging up to 20 mg (dry wt) of cells per ml, were ruptured after nitrogen saturation at 1740 psi. Under similar conditions, 10 to 25% of Brucella abortus and Staphylococcus aureus were ruptured. Rupture of these organisms produced readily separable cell walls. Centrifugation in linear glycerol gradients was applied to further separate cell walls from debris. Mycoplasma gallinarum, Leptospira pomona, and Eimeria tenella (avian coccidia) oöcysts were also broken up by the decompression chamber. Pressure and duration of saturation of cells with gas affected rupture efficiency. Within the limits of this study, concentration of organisms and volume of suspensions did not have a definite effect.

Bacteria↗
PubMed1997

Influence of the volume of osteonecrosis on the outcome of core decompression of the femoral head.

OBJECTIVES: To assess the outcome of core decompression in the treatment of osteonecrosis of the femoral head related to the volume of necrotic bone measured according to a previously reported method. METHODS: Twenty hips corresponding to strictly Ficat stage II underwent magnetic resonance imaging and the volume of necrotic bone was expressed as a percentage of the volume of the entire head measured on each slice. All hips underwent core decompression and the outcome was evaluated at 24 months. The primary evaluation criterion was radiological appearance: the outcome was considered as good if the hip remained stage II and poor if the disease progressed. RESULTS: Twenty four months after core decompression, half the cases remained stable and in half the disease had progressed. Outcome seemed to be related to the volume of necrotic bone (average 22% in the good outcome group versus 45% in the poor outcome group (p = 0.0051)) and was independent of risk factors, age, and histological type. CONCLUSIONS: The volume of necrotic bone should be taken into account in the evaluation of any treatment, bearing in mind that in more than one third of cases this volume will probably decrease, especially at the beginning of the disease process.

Adult↗
PubMed2000

Transconjunctival orbital decompression in Graves' ophthalmopathy: lateral wall approach ab interno.

AIMS: A modified surgical technique is described to perform a one, two, or three wall orbital decompression in patients with Graves' ophthalmopathy. METHODS: The lateral wall was approached ab interno through a "swinging eyelid" approach (lateral canthotomy and lower fornix incision) and an extended periosteum incision along the inferior and lateral orbital margin. In addition, the orbital floor and medial wall were removed when indicated. To minimise the incidence of iatrogenic diplopia, the lateral and medial walls were used as the first surfaces of decompression, leaving the "medial orbital strut" intact. During 1998, this technique was used in a consecutive series of 19 patients (35 orbits) with compressive optic neuropathy (six patients), severe exposure keratopathy (one patient), or disfiguring/congestive Graves' ophthalmopathy (12 patients). RESULTS: The preoperative Hertel value (35 eyes) was on average 25 mm (range 19-31 mm). The mean proptosis reduction at 2 months after surgery was 5.5 mm (range 3-7 mm). Of the total group of 19 patients, iatrogenic diplopia occurred in two (12.5%) of 16 patients who had no preoperative diplopia or only when tired. The three other patients with continuous preoperative diplopia showed no improvement of double vision after orbital decompression, even when the ocular motility (ductions) had improved. In the total group, there was no significant change of ductions in any direction at 2 months after surgery. All six patients with recent onset compressive optic neuropathy showed improvement of visual acuity after surgery. No visual deterioration related to surgery was observed in this study. A high satisfaction score (mean 8.2 on a scale of 1 to 10) was noted following the operation. CONCLUSION: This versatile procedure is safe and efficacious, patient and cost friendly. Advantages are the low incidence of induced diplopia and periorbital hypaesthesia, the hidden and small incision, the minimal surgical trauma to the temporalis muscle, and fast patient recovery. The main disadvantage is the limited exposure of the posterior medial and lateral wall.

Adult↗
PubMed1994

Effects of a patent foramen ovale on arterial saturation during exercise and on cardiovascular responses to deep breathing, Valsalva manoeuvre, and passive tilt: relation to history of decompression illness in divers.

OBJECTIVE: To determine whether the presence of a patent foramen ovale could result in significant arterial desaturation and affect the responses of heart rate and blood pressure to physiological manoeuvres and to determine whether responses differed between those with and those without prior clinical events associated with a patent foramen ovale. DESIGN: Blind controlled study. SETTING: Teaching hospital. PATIENTS: Divers with a large patent foramen ovale shown by contrast echocardiography and divided into those who had neurological decompression illness that started within 30 minutes of surfacing (group 1), those who had no history of decompression illness (group 2), and age and sex matched control divers who had no evidence of intracardiac shunts (group 3). MAIN OUTCOME MEASURES: The change in percentage haemoglobin oxygen saturation during treadmill exercise and the response of heart rate and blood pressure to physiological manoeuvres. RESULTS: There were no significant differences between the three groups but two divers in group 1 showed clinically important desaturation during exercise and unusual blood pressure and heart rate responses to passive tilt. These divers were notable for having the greatest number of episodes and the most severe single episode of spinal cord decompression illness. CONCLUSION: A large patent foramen ovale may be associated with clinically significant arterial desaturation and unusual responses of heart rate and blood pressure in some healthy subjects.

Arteries↗
PubMed1994

Neurophysiological assessment of divers with medical histories of neurological decompression illness.

OBJECTIVE: To examine the possibility that subclinical damage may persist after clinical recovery from neurological decompression illness. METHODS: The neuraxes of 71 divers with medical histories of neurological decompression illness and 37 non-diver controls were examined by recording the somatosensory evoked potentials produced on stimulation of the posterior tibial and median nerves. RESULTS: Although the tests gave some objective support for the presence of "soft" residual neurological symptoms and signs, no evidence was given for the presence of subclinical damage. CONCLUSIONS: The contention that neurological damage persists after full clinical recovery from the neurological decompression illness was not supported.

Adult↗
PubMed1995

Electroencephalographic study of divers with histories of neurological decompression illness.

OBJECTIVE: To determine whether divers with histories of neurological decompression illness are electroencephalographically distinguishable from non-divers. METHODS: The electroencephalograms (EEGs) from 68 divers with histories of neurological decompression illness and 45 non-diver controls were examined independently by two clinical neurophysiologists. RESULTS: The diver and non-diver groups were electroencephalographically indistinguishable. CONCLUSION: There is no electroencephalographic evidence for the existence of cerebral dysfunction in divers with histories of decompression illness.

Adult↗
PubMed2004

Acclimatization to neurological decompression sickness in rabbits.

Diving acclimatization refers to a reduced susceptibility to acute decompression sickness (DCS) in individuals undergoing repeated compression-decompression cycles. We demonstrated in a previous study that the mechanism responsible for this acclimatization is similar to that of stress preconditioning. In this study, we investigated the protective effect of prior DCS preconditioning on the severity of neurological DCS in subsequent exposure to high pressure in rabbits. We exposed the rabbits (n = 10) to a pressure cycle of 6 absolute atmospheres (ATA) for 90 min, which induced signs of neurological DCS in 60% of the animals. Twenty-four hours after the pressure cycle, rabbits with DCS expressed more heat-shock protein 70 (HSP70) in the lungs, liver, and heart than rabbits without signs of disease or those in the control group (n = 6). In another group of rabbits (n = 24), 50% of animals presented signs of neurological DCS after exposure to high pressure, with a neurological score of 46.5 (SD 19.5). A course of hyperbaric oxygen therapy alleviated the signs of neurological DCS and ensured the animals' survival for 24 h. Experiencing another pressure cycle of 6 ATA for 90 min, 50% of 12 rabbits with prior DCS preconditioning developed signs of DCS, with a neurological score of 16.3 (SD 28.3), significantly lower than that before hyperbaric oxygen therapy (P = 0.002). In summary, our results show that the occurrence of DCS in rabbits after rapid decompression is associated with increased expression of a stress protein, indicating that the stress response is induced by DCS. This phenomenon was defined as "DCS preconditioning." DCS preconditioning attenuated the severity of neurological DCS caused by subsequent exposure to high pressure. These results suggest that bubble formation in tissues activates the stress response and stress preconditioning attenuates tissue injury on subsequent DCS stress, which may be the mechanism responsible for diving acclimatization.

Acclimatization↗
PubMed2000

A model for influence of exercise on formation and growth of tissue bubbles during altitude decompression.

In response to exercise performed before or after altitude decompression, physiological changes are suspected to affect the formation and growth of decompression bubbles. We hypothesized that the work to change the size of a bubble is done by gas pressure gradients in a macro- and microsystem of thermodynamic forces and that the number of bubbles formed through time follows a Poisson process. We modeled the influence of tissue O(2) consumption on bubble dynamics in the O(2) transport system in series against resistances, from the alveolus to the microsystem containing the bubble and its surrounding tissue shell. Realistic simulations of experimental decompression procedures typical of actual extravehicular activities were obtained. Results suggest that exercise-induced elevation of O(2) consumption at altitude leads to bubble persistence in tissues. At the same time, exercise-enhanced perfusion leads to an overall suppression of bubble growth. The total volume of bubbles would be reduced unless increased tissue motion simultaneously raises the rate of bubble formation through cavitation processes, thus maintaining or increasing total bubble volume, despite the exercise.

Altitude↗
PubMed1980

Pathophysiology of inner ear dysfunction in the squirrel monkey in rapid decompression.

More than 90 squirrel monkeys with bilateral myringotomies (a small hole in each ear drum) were rapidly decompressed in a hyperbaric chamber according to a special diving profile in which 35% of attempts produced disorders ("hits") confined to the inner ear. Monkeys receiving inner ear hits (as determined by the sudden onset of vigorous head or eye nystagmus during decompression) were tested and killed at times ranging from 1 h to more than 12 mo following the dive. Histologically, in monkeys killed 1 mo or less after the hit, hemorrhage and/or a deep purple-staining precipitated material were frequently found in the otic fluid spaces. In those monkeys killed more than 1 mo after a hit, ectopic new bone growth in the arms of the semicircular canals was a common sequela. New bone growth never appeared in the cochlea. In unaffected ears, and in both ears of control animals, the precipitated material was somewhat less than in ears damaged by decompression; and, furthermore, new bone growth did not occur. Behaviorally, the hit monkeys showed vestibular deficits that were consistent with the structural damage revealed by histology.

Animals↗
PubMed1986

Hyperbaric-induced subfertility in mice: lack of effect of decompression.

Male mice were exposed to 50 atmospheres absolute (ATA). He for 30 min, twice weekly for 5 wk and their fertility assessed by subsequently mating with untreated virgin females. The exposure schedule was designed to provide compression and decompression times the same as previous positive studies of hyperbaric-induced subfertility but with much shorter periods at maximum pressure (30 min vs. 24 h). We postulated that, if subfertility were associated with exposure to pressure per se rather than with compression or decompression, then the present experiments would fail to produce a decrease in male fertility. The data were compared with those of a control group placed in the hyperbaric chamber at 1 ATA. The pregnancy rate for exposed vs. control mice was 89 vs. 86%, and the mean live liter size was 6.2 vs. 5.6. There were no statistically significant differences between these and other indexes of male fertility, and the results support our hypothesis that the hyperbaric-induced subfertility in male mice is not associated with these decompression procedures.

Animals↗
PubMed1987

Relation between complement activation and susceptibility to decompression sickness.

The consequences of complement activation and the symptoms of decompression sickness are similar. Consequently, the relation between the sensitivity of individuals to complement activation by air bubbles and their susceptibility to decompression sickness has been examined. Plasma samples from 34 individuals were incubated with air bubbles, and the concentration of the fluid phase metabolites of complement activation C3a, C4a, and C5a were measured with radioimmunoassays. It was found that both the anaphylatoxins C3a and C5a were produced by the presence of air bubbles but that the anaphylatoxin C4a was not. This finding indicates that air bubbles activate the complement system by the alternate pathway. One group of individuals was found to be particularly sensitive to complement activation by this pathway. They produced 3.3 times more C3a and 5.3 times more C5a in their plasma samples incubated with air bubbles as did the other group. Sixteen individuals were subjected to a series of pressure profiles that were severe enough to produce bubbles in their circulatory system that could be detected by Doppler ultrasonic monitoring. The group of individuals that had been identified as being more sensitive to complement activation by the alternate pathway was also found to be more susceptible to decompression sickness.

Adult↗
PubMed2000

Natural history of severe decompression sickness after rapid ascent from air saturation in a porcine model.

We developed a swine model to describe the untreated natural history of severe decompression sickness (DCS) after direct ascent from saturation conditions. In a recompression chamber, neutered male Yorkshire swine were pressurized to a predetermined depth from 50-150 feet of seawater [fsw; 2.52-5.55 atmospheres absolute (ATA)]. After 22 h, they returned to the surface (1 ATA) at 30 fsw/min (0.91 ATA/min) without decompression stops and were observed. Depth was the primary predictor of DCS incidence (R = 0.52, P < 0.0001) and death (R = 0.54, P < 0.0001). Severe DCS, defined as neurological or cardiopulmonary impairment, occurred in 78 of 128 animals, and 42 of 51 animals with cardiopulmonary DCS died within 1 h after surfacing. Within 24 h, 29 of 30 survivors with neurological DCS completely resolved their deficits without intervention. Pretrial Monte Carlo analysis decreased subject requirement without sacrificing power. This model provides a useful platform for investigating the pathophysiology of severe DCS and testing therapeutic interventions. The results raise important questions about present models of human responses to similar decompressive insults.

Air Pressure↗
PubMed2002

Hyperbaric oxygen may reduce gas bubbles in decompressed prawns by eliminating gas nuclei.

It is accepted that gas bubbles grow from preexisting gas nuclei in tissue. The possibility of eliminating gas nuclei may be of benefit in preventing decompression sickness. In the present study, we examined the hypothesis that hyperbaric oxygen may replace the resident gas in the nuclei with oxygen and, because of its metabolic role, eliminate the nuclei themselves. After pretreatment with oxygen, prawns were 98% saturated with nitrogen before explosive decompression at 30 m/min. Ten transparent prawns were exposed to four experimental profiles in a crossover design: 1) 10-min compression to 203 kPa with air; 2) 10-min compression with oxygen; 3) 10-min compression with oxygen to 203 kPa followed by 12 min air at 203 kPa; and 4) 10 min in normobaric oxygen followed by compression to 203 kPa with air. Bubbles were measured after explosive decompression. We found that pretreatment with hyperbaric oxygen (profile C) significantly reduces the number of bubbles and bubble volume. We suggest that hyperbaric oxygen eliminates bubble nuclei in the prawn.

Animals↗
PubMedDate not supplied

Indication and technique of transnasal microscopic orbital decompression for endocrine ophthalmopathy.

If endocrine ophthalmopathy progresses despite conservative treatment then indications for surgical decompression are: loss of visual acuity, increasing strabism, and severe keratopathy. Endonasal microsurgery ensures a binocular view onto the intranasal landmarks of the orbital walls and allows simultaneous decompression of the medial and inferior wall as well as a good relief of pressure at the orbital apex. Surgical decompressions were performed on 29 orbits in 19 patients, 16 by using the endonasal microsurgical, 3 via external approach. The microscopic approach was entirely comparable with regard to the reduction of proptosis with a mean improvement of 4.2 mm against a mean of 4.7 mm by external approach and a mean 0.2 of better visual acuity in both procedures. The microsurgical technique is considered superior to an external approach avoiding external scars, neural pain, and reportedly less diplopia. The healing phase and the hospitalization time are shorter.

Adult↗