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Movement by helicopter of patients with decompression sickness.

Rapid movement of a patient with decompression sickness sometimes poses problems when the site of the hyperbaric treatment facility is located a considerable distance away. Six cases of aviator decompression sickness were diagnosed in altitude chamber participants during an 18-month period. Five cases were uncomplicated decompression sickness and the sixth case was of central nervous system decompression sickness. All cases were transferred by low-level helicopter flight. No complications were noted when the helicopter stayed within 200 ft (61 m) AGL of the take-off point. Symptoms of decompression sickness did worsen however, when this altitude was exceeded. This study shows that movement of patients with decompression sickness by low-level helicopter flight is both safe and effective, especially when pressurized aircraft is neither available nor practical.

Adult↗

[Clinical aspects, pathophysiology and therapy of decompression sickness].

The primary treatment of decompression illnesses (arterial gas embolism and all types of decompression sickness) is recompression therapy, combined with hyperbaric oxygen breathing. It is essential to initiate treatment as soon as the symptoms arise. However, prior to hyperbaric oxygen therapy--particularly with any delay in starting recompression--specific supportive therapy for severe decompression-related injuries is mandatory after first-aid treatment has been given. The preferred supportive treatment would be 100% normobaric oxygen breathing, oral or better i.v. fluids (crystalloids or dextrose saline), flat position on the back, and organization of appropriate means of transportation to the nearest hyperbaric center. Large doses of corticosteroids as well as anticoagulants are under discussion, but there is some evidence that steroids and medium doses of acetylsalicylic acid, given initially, may be of certain benefit for patients suffering from cerebral- and spinal-cord trauma due to decompression accidents. There is evidence that latency of onset of decompression illnesses is a prognostic indicator. Nevertheless, urgent HBO therapy in a hyperbaric chamber suitable for intensive care under pressure is mandatory for all severe decompression disorders.

Decompression Sickness↗

Dibutyryl cAMP effects on thromboxane and leukotriene production in decompression-induced lung injury.

Decompression-induced venous bubble formation has been linked to increased neutrophil counts, endothelial cell injury, release of vasoactive eicosanoids, and increased vascular membrane permeability. These actions may account for inflammatory responses and edema formation. Increasing the intracellular cAMP has been shown to decrease eicosanoid production and edema formation in various models of lung injury. Reduction of decompression-induced inflammatory responses was evaluated in decompressed rats pretreated with saline (controls) or dibutyryl cAMP (DBcAMP, an analog of cAMP). After pretreatment, rats were exposed to either 616 kPa for 120 min or 683 kPa for 60 min. The observed increases in extravascular lung water ratios (pulmonary edema), bronchoalveolar lavage, and pleural protein in the saline control group (683 kPa) were not evident with DBcAMP treatment. DBcAMP pretreatment effects were also seen with the white blood cell counts and the percent of neutrophils in the bronchoalveolar lavage. Urinary levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were significantly increased with the 683 kPa saline control decompression exposure. DBcAMP reduced the decompression-induced leukotriene E4 production in the urine. Plasma levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were increased with the 683-kPa exposure groups. DBcAMP treatment did not affect these changes. The 11-dehydrothromboxane B2 and leukotriene E4 levels in the bronchoalveolar lavage were increased with the 683 kPa exposure and were reduced with the DBcAMP treatment. Our results indicate that DBcAMP has the capability to reduce eicosanoid production and limit membrane permeability and subsequent edema formation in rats experiencing decompression sickness.

Animals↗

Gas phase separation during decompression in man: ultrasound monitoring.

During two dive series, one to 132 fsw and one to 210 fsw, Doppler ultrasonic bubble detectors were used to monitor venous gas bubbles in divers during decompression and for 30 min thereafter. Various decompression schedules were used. Bubble scores were evaluated by independent listerners to tape recordings in a blind manner. A significant increase in bubble scores throughout the stages of decompression and postdecompression was demonstrated as well as a statistically significant relationship between bubble score and decompression sickness. A reduction in mean bubble score was found in divers who made an additional deep decompression stop that was unrelated to the extension of the decompression time. The implications of these findings are discussed.

Adult↗

Transmastoid decompression of the facial nerve in Bell's palsy.

We describe the technique of decompression of the facial nerve from the geniculate ganglion to the stylomastoid foramen. The decompression was made on 51 patients with Bell's palsy, and the results of follow-up study were compared with those of 77 patients in whom the pyramidal and vertical segments were decompressed. The decompressions were indicated when a severe denervation of the nerve was confirmed by electrodiagnostic examinations. Incidences of notable residual palsy and of pronounced sequelae were always lower in the former group of patients regardless of the operational timing. In either group, a more desirable result was obtained by the decompression within 30 days, but a favorable effect of the decompression was recognizable even when the surgery was performed between 31 and 90 days after the onset.

Adolescent↗

Orbital decompression in Graves' disease.

OBJECTIVE: The authors' experience with surgical decompression of the orbits in patients with Graves' orbitopathy is reviewed. DESIGN: One hundred twenty-six consecutive primary orbital decompressions were retrospectively studied. SETTING: Tertiary care university hospitals. PATIENTS: All patients were referred by ophthalmologists for surgical decompression after failure of a trial of oral steroid therapy, and many had had orbital irradiation. INTERVENTION: Antral-ethmoidal or transconjunctival surgical decompression was accomplished in all. MAIN OUTCOMES: Measurements of visual acuity, ocular motility, and proptosis were accomplished preoperatively and a minimum of 3 months postoperatively. Surgical complications were tallied. RESULTS: Mean reduction of proptosis by antral-ethmoidal decompression was 5.3 mm, and 3.6 mm by the transconjunctival approach. Visual acuity improved in 34 orbits, was unchanged in 91 orbits, and decreased in one orbit. In a subgroup of 30 patients in whom ocular motility was quantified by prism cover test preoperatively, motility was unchanged or improved in 21 and was decreased in nine. Complications were infrequent. CONCLUSION: The antral-ethmoidal and transconjunctival approaches to orbital decompression are safe and effective.

Adolescent↗

Compartment syndrome in experimental chronic obstructive pancreatitis: effect of decompressing the main pancreatic duct.

Chronic pancreatitis is characterized by persistent and severe pain, which can be relieved by decompression of the main pancreatic duct (MPD). Both ductal and interstitial pressures have been shown to be increased in chronic pancreatitis in patients. A study was carried out of pancreatic interstitial pressure and pancreatic blood flow in normal cats and those in which chronic obstructive pancreatitis had been induced 5 weeks earlier to determine the effect of decompression of the MPD. In the normal pancreas, median(interquartile range (i.q.r.)) basal interstitial pressure was 0.05(1.2) mmHg and median(i.q.r.) basal pancreatic blood flow 58.3(24.3) ml per min per 100 g. Secretory stimulation did not change the interstitial pressure significantly, but was associated with a 40 per cent increase in median(i.q.r.) blood flow to 81.8(45.8) ml per min per 100 g. In contrast, in chronic obstructive pancreatitis, the median(i.q.r.) basal interstitial pressure was 2.0(1.5) mmHg, which was significantly higher than in the normal gland, and median(i.q.r.) pancreatic blood flow was 38.3(9.8) ml per min per 100 g, significantly lower than in the normal pancreas. Furthermore, secretory stimulation was associated with a significant increase in median(i.q.r.) interstitial pressure to 3.3(1.6) mmHg and a simultaneous decrease in median(i.q.r.) blood flow to 31.5(13.7) ml per min per 100 g. After decompression of the MPD in cats with chronic obstructive pancreatitis, the median(i.q.r.) basal interstitial pressure was 2.0(1.4) mmHg and on secretory stimulation 1.8(1.5) mmHg. Decompression thus prevented the increase in interstitial pressure seen in the animals with obstruction. In contrast, ductal decompression improved the median(i.q.r.) basal pancreatic blood flow to 45.9(38.4) ml per min per 100 g and, furthermore, this increased significantly on secretory stimulation to a median(i.q.r.) of 81.4(47.8) ml per min per 100 g. Decompression thus restored the normal pattern of secretory hyperaemia. Within the confines of this model, these observations demonstrate that chronic obstructive pancreatitis exhibits a compartment syndrome that is relieved by duct drainage.

Animals↗

Repeated decompressive craniectomy after head injury in children: two successful cases as result of improved neuromonitoring.

BACKGROUND Decompressive craniectomy in the treatment of posttraumatic brain swelling is not generally accepted. Until now the efficacy of operative decompressive craniectomy in posttraumatic brain swelling of children appeared more promising. However, the criteria for such procedures remain unclearly defined. METHODS We present two children who had repeated decompressive craniectomy following head injury, in order to control intracranial pressure (ICP) sufficiently. Our indications for performing a decompressive craniectomy in the presence of conservatively uncontrollable raised ICP are: (1) Patient is between the ages of 3 and 35 years. (2) An initial Glasgow Coma Scale (GCS) ranging between 4 and 8. (3) Three criteria have to be fulfilled at the same time: The cerebral perfusion pressure (CPP) has to drop to values of less than 60 mm Hg. It is impossible to control the ICP values (up to 45 mm Hg) conservatively. The diastolic velocity of the transcranial doppler sonography (TCD) has to decrease until only a systolic flow pattern is obtained. (4) No other mass lesion should be detected on cranial computed tomography (CCT) that could account for the rise in pressure. In both cases we performed bifrontal decompressive craniectomies. RESULTS Both patients survived. Seven months after the accident, patient No. 1 was oriented and could walk on her own with a mild right-side hemiparesis. Patient No. 2 could attend school 12 months postinjury. Both patients developed hygromas after the craniectomy. A shunt operation, however, was not necessary. CONCLUSIONS ICP monitoring, together with CCT examination, simultaneous recording of TCD, and systemic parameters, will reveal a patient at risk at a time when impending damage due to uncontrollable ICP may still be prevented. The simultaneous assessment of cerebral blood flow by transcranial doppler (TCD), in this situation, proves most valuable. It improves the guidelines of patient selection for decompressive craniectomy, in the presence of conservatively uncontrollable ICP.

Brain Edema↗

Clinical and laboratory investigations of active compression-decompression cardiopulmonary resuscitation.

Based upon an anecdotal report of successful resuscitation using a toilet plunger, Cohen and co-workers have developed and investigated a hand-held suction cup as an adjunct to standard manual CPR. This new method, called active compression-decompression cardiopulmonary resuscitation, utilizes a device which is placed over the mid-sternum, approximately 1-2 inches above the lower rib cage border. Active compression-decompression cardiopulmonary resuscitation is then performed in accordance with American Heart Association guidelines at a rate equal to 80-100/min using a 50% duty cycle and compression depth of 1.5-2.0 inches. Initial studies using the ACD device in both models and human subjects late after cardiac arrest have demonstrated improved cardiopulmonary hemodynamics when compared to standard manual CPR. Transophageal echocardiographic studies in human subjects have shown increased left ventricular filling during active decompression suggesting that active chest decompression improves venous return to the heart thus increasing left ventricular volume and stroke volume. Improved resuscitation success has also been documented in human subjects after in-hospital and pre-hospital cardiac arrest. Active compression-decompression cardiopulmonary resuscitation is a simple method which utilizes a hand held suction cup as an interface between rescuer and victim during closed chest circulatory support. This method allows for standard manual cardiopulmonary resuscitation with the addition of active chest wall decompression and appears to be a beneficial adjunct to standard manual cardiopulmonary resuscitation.

Blood Flow Velocity↗

Correction of congenital hydronephrosis in utero IV: in utero decompression prevents renal dysplasia.

Renal dysplasia (RD) is commonly seen in babies with urinary tract obstruction (UTO). Recent experimental evidence suggests that early fetal UTO leads to the development of RD. The RD seen in children with congenital UTO is usually not reversible, even when the obstruction is relieved soon after birth. Is the RD associated with congenital UTO preventable or reversible by decompression of the urinary tract early in gestation? If so, at what stage of development must this decompression be performed? We produced complete unilateral ureteral obstruction in 25 early second trimester (62 to 65 days) lamb fetuses, a procedure that results in ipsilateral RD at term (140 days). At a second operation, 20, 40, or 60 days after the initial procedure, we decompressed the obstructed kidney by a cutaneous end-ureterostomy. The contralateral unobstructed kidneys served as controls. Renal function (urine output and iothalamate clearance) and histopathology were evaluated after delivery at term. Recovery of renal function was directly proportional to the duration of in utero decompression and inversely proportional to duration of obstruction. In addition, in utero decompression prevented or greatly ameliorated the development of RD. However, some postobstructive changes persisted; these were proportional to the length of in utero obstruction. These results substantiate the clinical impression that some human fetuses with congenital UTO may benefit from early in utero decompression.

Animals↗

Progressive and static nonarteritic ischemic optic neuropathy treated by optic nerve sheath decompression.

PURPOSE: Optic nerve sheath fenestration has been advocated as an effective treatment for progressive nonarteritic ischemic optic neuropathy (NAION) and anecdotally effective for selected patients with NAION who have not had progressive visual loss. To determine whether optic nerve sheath decompression is of any benefit in patients with NAION, the authors reviewed their experience, surgically treating 23 patients with progressive NAION and 15 patients with static or nonprogressive NAION. RESULTS: Patients with progressive NAION had a significant improvement in visual function as measured by Snellen visual acuity after optic nerve sheath decompression (P = 0.0005). There was no statistically significant improvement in visual field mean deviation (P = 0.11). The 15 patients undergoing optic nerve sheath decompression for static NAION failed to demonstrate significant improvement in either visual acuity (P = 0.90) or visual field mean deviation (P = 0.87). Preoperative standardized echography was used to measure the optic nerve sheath diameter and ascertain its compressibility (30 degrees test). There was a significant difference in compressibility between eyes with static NAION and eyes with progressive NAION (P = 0.001). Accumulation of optic nerve sheath fluid was documented in three eyes initially presenting with NAION and then with development of progressive visual dysfunction. CONCLUSION: Optic nerve sheath decompression improves visual acuity but has little effect on overall visual function in patients with progressive NAION. Optic nerve sheath decompression does not improve visual field or acuity in patients with static NAION. Detection of significant intrasheath fluid by standardized echography helps to objectively differentiate patients with NAION who may benefit from optic nerve sheath decompression.

Adult↗

Ventilatory effects of active compression-decompression in dogs.

STUDY OBJECTIVE: To determine the ventilatory effect of active compression-decompression CPR and to compare it with two other techniques, standard manual cardiac massage and mechanical cardiac massage. DESIGN: Prospective, randomized laboratory investigation. PARTICIPANTS: Mongrel dogs. INTERVENTIONS: Nine adult mongrel dogs were anesthetized, intubated, and mechanically ventilated. They were instrumented to measure arterial pressure, esophageal pressure, airway pressure, end-tidal carbon dioxide concentration, and minute ventilation. RESULTS: After induction of ventricular fibrillation, three sequences of cardiac massage were performed randomly during mechanical ventilation, standard cardiac massage, mechanical cardiac massage, and active compression-decompression technique. The animals then were disconnected from the ventilator, and the three sequences were performed again. Active compression-decompression created negative minimum esophageal pressures and significantly decreased the minimum airway pressure as compared with the other techniques. Whatever the ventilatory condition, minute ventilation was increased dramatically during active compression-decompression. CONCLUSION: In this model of cardiac arrest, an important increase in minute ventilation was observed during active compression-decompression. This effect was significantly greater than the increases observed with other techniques of cardiac massage and was related to the negative pressure generated by active decompression.

Airway Resistance↗

Measuring forces and frequency during active compression decompression cardiopulmonary resuscitation: a device for training, research and real CPR.

Active compression decompression (ACD) cardiopulmonary resuscitation (CPR) is possibly a superior alternative to standard (STD) CPR, but an optimal compression and decompression pattern has to be ensured. ACD-CPR can be evaluated during CPR training sessions using commercially available manikins; however devices for recording compression and decompression forces or frequency during real CPR are lacking. Using the Ambu CardioPump without changing its mechanical characteristics, two force transducers were integrated into the ACD device. Using specially designed electronics and a portable computer, compression and decompression forces were measured and displayed continuously and compression frequency and the compression decompression phase are calculated on-line during real CPR action. All measured parameters were stored on a hard disk for later retrieval and analysis. Linearity of force measurement was better than 6% within a -250- +500 N range. The error in repeatability was below 5% thus outperforming the original mechanical force measurement system of the Ambu CardioPump. Compression frequency was calculated very accurately (error < 1%). The system has been successfully used during CPR training, during ACD-CPR in 37 corpses under research conditions and in five out-of-hospital CPR casualties. Simple and safe in use, our modified CardioPump with integrated electronics provides an important, technically advanced solution for monitoring ACD-CPR on-line. It warrants quality assurance during ACD-CPR training and in real CPR scenarios and guarantees accurate recording of compression and decompression forces and compression frequency.

Cadaver↗

Anterior decompression and fusion for ossification of the posterior longitudinal ligament of the upper thoracic spine causing myelopathy: using the manubrium splitting approach.

The effectiveness and problems associated with the operation of anterior decompression and fusion using the manubrium splitting approach for thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL) of the upper thoracic spine carried out in nine patients was investigated. They were followed up for 1 year or more following the operation. The severity of the thoracic myelopathy was evaluated using the Japanese Orthopaedic Association score, and the surgical outcome was evaluated using recovery rates. This study includes investigation of the surgical outcome and of any postoperative complications, and radiographic observation of bony union and the progression of OPLL within the area of the anterior decompression. The caudal limit of the anterior decompression achieved by splitting the manubrium was the T3 vertebral body. A recovery rate of 71% was achieved during an average follow-up period of 35 months. Only one transient recurrent nerve palsy, and in another patient cerebrospinal fluid leakage occurred as postoperative complications. Radiographic examinations confirmed bony union in all of the patients, and there was no instance of spinal canal stenosis caused by progression of the OPLL within the area of the anterior decompression. Anterior decompression and fusion by splitting the manubrium was an effective surgical procedure for OPLL of the upper thoracic spine, to achieve a good outcome, however, the extent of anterior decompression was limited.

Adult↗

Usefulness of Dennis Colorectal Tube in endoscopic decompression of acute, malignant colonic obstruction.

BACKGROUND: Colonoscopic decompression has been attempted in patients with acute colonic obstruction caused by colon cancer to avoid emergency surgery and multiple subsequent operations but has usually been unsuccessful. This is an evaluation of the usefulness of a new device for endoscopic decompression in these patients. METHODS: Nine consecutive patients (6 men, 3 women; 65 to 89 years of age) with acute colonic obstruction resulting from colon cancer underwent endoscopic decompression with a Dennis Colorectal Tube. RESULTS: In all 9 patients (1 with carcinoma of the sigmoid colon, 3 with carcinoma of descending colon, 2 with carcinoma of the transverse colon, 2 with carcinoma of the ascending colon, and 1 with carcinoma of the cecum), endoscopic decompression was successful. After decompressing and cleansing the colon for several days, a one-stage operation was possible in all patients. CONCLUSION: Dennis Colorectal Tube is an excellent device for endoscopic decompression of acute, malignant colonic obstruction.

Acute Disease↗

Optic nerve decompression in fibrous dysplasia: indications, efficacy, and safety.

Optic nerve decompression is controversial in posttraumatic visual loss and as a prophylactic therapy in fibrous dysplasia involving the optic canal. It is less controversial for the treatment of optic nerve compression in fibrous dysplasia. Thirteen patients with craniomaxillofacial fibrous dysplasia who underwent 16 optic nerve decompressions at the Chang Gung Craniofacial Centre for both therapeutic (10) and prophylactic (6) indications are reported. One patient sustained a clinically useful improvement in vision in response to two therapeutic decompressions, and another demonstrated marked improvement after therapeutic decompression, with visual acuity improving from 0.4 to 1.0 in the affected eye. No patient underwent a permanent deterioration of vision as a result of either therapeutic or prophylactic decompression. One patient suffered extraocular muscle dysfunction that was corrected with strabismus surgery. A review of the literature clarifies the controversies and allows establishment of indications for optic nerve decompression.

Adolescent↗

Bilateral transpedicular decompression and Harrington rod stabilization in the management of severe thoracolumbar burst fractures.

Fifty-eight patients with severe thoracolumbar burst fractures were treated with bilateral transpedicular decompression, Harrington rod instrumentation, and spine fusion. Spinal realignment and stabilization was achieved by contoured dual Harrington distraction rods supplemented by segmental sublaminal wiring. Posterior element fractures were noted in 25 patients, 9 of whom had associated dural tears. Computed tomography was performed to assess the cross-sectional area of the spinal canal before surgery and after decompression. Patients at initial evaluation averaged greater than 67% spinal canal compromise. After surgery, successful decompression was accomplished in 57 patients. One patient required staged, anterior thoracoabdominal decompression and fibula strut grafting. At follow-up (average, 43 months; range, 25-70 months), neurologic improvement was found in 77% of the patients who initially presented with neurologic deficits. Thirty-four of 40 patients with incomplete paraplegia improved one or more subgroups on the Frankel scale. A solid fusion was attained in all 58 patients. No patient had a significant residual kyphotic deformity. Single-stage bilateral transpedicular decompression and dual Harrington rod instrumentation reliably provides decompression of the spinal canal and restores spinal alignment. The procedure allows early mobilization and provides an environment for solid fusion and maximum neurologic return.

Adult↗

Long-term follow-up study of anterior decompression and fusion for thoracic myelopathy resulting from ossification of the posterior longitudinal ligament.

STUDY DESIGN: This was a retrospective study of the results of anterior decompression and fusion in patients with thoracic myelopathy secondary to ossification of the posterior longitudinal ligament with a minimum follow-up time of 5 years. OBJECTIVES: To clarify the effectiveness and limits of anterior decompression and fusion for thoracic ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Posterior decompression for the surgical management of thoracic ossification of the posterior longitudinal ligament has had an uncertain success record. Anterior decompression and fusion have been considered the treatment of choice however, there are few reports describing the long-term results. METHODS: The participants in this investigation were 33 patients whose cases were followed for an average period of 8 years and 2 months. The factors that were investigated included changes in the Japanese Orthopedic Association score and in recovery rates, postoperative complications, and radiographic findings of bone union and progression of ossification of the posterior longitudinal ligament within the area of anterior decompression. RESULTS: Although the recovery rates were relatively stable from 1-5 years after surgery, the rates declined thereafter. The average recovery rate at the final follow-up visit was 53.2%. Postoperative complications included three cases of deterioration of thoracic myelopathy and four cases of extrapleural cerebrospinal fluid leakage. Except for the one case of deterioration of thoracic myelopathy, the remainder of the complications were transient. CONCLUSIONS: Anterior decompression and fusion is an effective surgical procedure for thoracic ossification of the posterior longitudinal ligament with good, stable, long-term results; when thoracic ossification of the posterior longitudinal ligament was extensive or coincident with ossification of the intraspinal ligament, however, the results were not as predictable.

Adult↗