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PubMed1992

A multisensor solid-state pressure manometer to identify the level of collapse in obstructive sleep apnea.

The cause of failure after uvulopalatopharyngoplasty (UPPP) in idiopathic obstructive sleep apnea (OSA) is poorly understood, but has been speculated to be due, in part, to persistent collapse in the lower oropharynx. In order to determine the specific level of upper airway obstruction during sleep, a multisensor pressure catheter has been developed with five solid-state ultraminiature sensors. Four sensors in the pharynx simultaneously measure multiple pressure levels, with no need to move the catheter during sleep. One distal esophageal port measures the respiratory effort. To evaluate the use of this catheter, manometry in twelve patients was reviewed and compared the use of this catheter, manometry in twelve patients was reviewed and compared to simultaneous videoendoscopy. The initial site of obstruction was the palate in nine patients (75%) and the tongue base in three (25%). Three patients with initial obstruction at the palate manometrically demonstrated distal obstruction on subsequent occluded breaths. Furthermore, simultaneous videoendoscopy in four patients with a palatal level of obstruction also identified marked near-total visual collapse without obstruction of the lower oropharynx that was not identified by pharyngeal manometry. The endoscopy revealed that at the initial site of obstruction, collapse appeared to have occurred passively during expiration and not on inspiration. Inferior to the site of manometric obstruction, collapse occurred during inspiration associated with increased negative inspiratory pressures. These results demonstrate that a multisensor pressure catheter can objectively identify the level of obstruction during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization↗
PubMed1996

Stent flexibility: an essential feature in the treatment of dynamic airway collapse.

Implantation of endobronchial stents for treatment of dynamic airway collapse represents a suitable therapeutic option to alleviate distressing symptoms. We report the case of a 43 year old patient suffering from progressive respiratory distress 2 weeks after insertion of a balloon-expandable radial noncompliant Palmaz stent in an unstable segment of the left main bronchus, with the aim of preventing symptomatic airway collapse. Bronchial instability had developed following sleeve resection of the right lung due to adenoid cystic carcinoma. Explanation revealed compression and deformation of the stent. Peak expiratory flow (PEF) had declined a low of 1.38 L.s-1 (forced expiratory volume in one second (FEV1) 1.02 L). With placement of a Strecker stent, having the ability to re-expand within certain limits, bronchial collapse could be avoided and marked clinical improvement as well as expiratory flow increase was noted (PEF 7.10 L.s-1; FEV1 = 2.03 L). At 13 months follow-up, clinical status was unchanged. A decline in forced expiratory flow (PEF 5.96 L.s-1; FEV1 1.69 L), however, indicated a possible change in the structural integrity of the Strecker stent. We conclude that physical properties of endobronchial stents may be crucial for good functional results in major airway collapse. Stiff prostheses, when compressed, can induce severe airway obstruction.

Adult↗
PubMed1999

Growth cones stall and collapse during axon outgrowth in Caenorhabditis elegans.

During nervous system development, neurons form synaptic contacts with distant target cells. These connections are formed by the extension of axonal processes along predetermined pathways. Axon outgrowth is directed by growth cones located at the tips of these neuronal processes. Although the behavior of growth cones has been well-characterized in vitro, it is difficult to observe growth cones in vivo. We have observed motor neuron growth cones migrating in living Caenorhabditis elegans larvae using time-lapse confocal microscopy. Specifically, we observed the VD motor neurons extend axons from the ventral to dorsal nerve cord during the L2 stage. The growth cones of these neurons are round and migrate rapidly across the epidermis if they are unobstructed. When they contact axons of the lateral nerve fascicles, growth cones stall and spread out along the fascicle to form anvil-shaped structures. After pausing for a few minutes, they extend lamellipodia beyond the fascicle and resume migration toward the dorsal nerve cord. Growth cones stall again when they contact the body wall muscles. These muscles are tightly attached to the epidermis by narrowly spaced circumferential attachment structures. Stalled growth cones extend fingers dorsally between these hypodermal attachment structures. When a single finger has projected through the body wall muscle quadrant, the growth cone located on the ventral side of the muscle collapses and a new growth cone forms at the dorsal tip of the predominating finger. Thus, we observe that complete growth cone collapse occurs in vivo and not just in culture assays. In contrast to studies indicating that collapse occurs upon contact with repulsive substrata, collapse of the VD growth cones may result from an intrinsic signal that serves to maintain growth cone primacy and conserve cellular material.

Animals↗
PubMed1983

Lobar collapse in the surgical intensive care unit.

The chest X rays of 200 consecutive patients in the surgical Intensive Care Unit were reviewed. Eighteen cases of lobar collapse were diagnosed in 17 patients (8.5%) with a high degree of certainty. Most cases involved the left lower lobe (12/18, 66%), but collapse of the right lower lobe (4/18, 22%) and the right upper lobe (2/18, 11%) was also noted. Although theories have been postulated to account for the high incidence of left lower lobe collapse following cardiac surgery, the predominance of left lower lobe collapse generally amongst ICU patients is not fully explained.

Child↗
PubMed2005

Sound signature for identification of tracheal collapse and laryngeal paralysis in dogs.

The aims of this study were to investigate whether upper airway sounds of dogs with laryngeal paralysis and tracheal collapse have distinct sound characteristics, compared with unaffected dogs. The sounds of 5 dogs with laryngeal paralysis and 5 dogs with tracheal collapse were recorded. Honking sound appeared as predominant clinical signs in dogs with tracheal collapse. Laryngeal stridors appeared as predominant clinical signs in dogs with experimentally produced laryngeal paralysis by resection of laryngeal nerve, in which two types of stridor, I and II, were recorded. All these sounds were analyzed using sound spectrogam analysis. There were significant differences in duration (sec), intensity (dB), pitch (Hz), first formant (Hz), second formant (Hz), third formant (Hz), fourth formant (Hz) of sounds between the normal bark and two types of stridor or honking sound, indicating that the sound analysis might be a useful diagnostic modality for dogs with tracheal collapse and laryngeal paralysis.

Animals↗
PubMed2003

Intravenous valproate associated with circulatory collapse.

OBJECTIVE: To report a case of severe circulatory collapse following an intravenous injection of sodium valproate. CASE SUMMARY: A 5-year-old white girl, who was receiving vasopressor support, developed a severe circulatory collapse following an intravenous injection of valproate 480 mg. Her invasive arterial blood pressure dropped after valproate was started, and she went into cardiac arrest requiring full resuscitation including 2 doses of epinephrine. She was successfully resuscitated. DISCUSSION: To the best of our knowledge, this is the first case report of such severe circulatory collapse associated with intravenous valproate. Although hypotension has been reported following the use of intravenous valproate, severe circulatory compromise leading to cardiorespiratory arrest has not been previously described. An objective causality assessment using the Naranjo probability scale revealed that the adverse drug event was highly possible. CONCLUSIONS: In view of this patient's circulatory collapse associated with valproate, intravenous sodium valproate should be used with caution, particularly in hemodynamically unstable patients.

Child, Preschool↗
PubMed2004

Role of dispersion in multiple-collapse dynamics.

The multiple-collapse dynamics of ultrashort pulses along the propagation direction are investigated under conditions of both normal and anomalous group-velocity dispersion (GVD). In the anomalous-GVD regime we find that collapse events can occur at locations in the medium many diffraction lengths beyond the initial collapse point, in contrast with the normal-GVD regime in which multiple collapse occurs within a diffraction length. Numerical simulations of a modified nonlinear envelope equation are found to be in good qualitative agreement with the observed lengths of the filaments.

Journal Article↗
PubMed1995

The detection of collapsible airways contributing to airflow limitation.

The detection of collapsible airways, which may be a component of asthma and emphysema, has important therapeutic implications. We describe a patient with significant airways collapse contributing to his airflow limitation and discuss how collapsible airways can be assessed by the volume difference between what exits the lung as determined by a spirometer and the volume compressed as measured by the plethysmograph. More simply, a large volume difference between the slow and forced vital capacity (SVC-FVC), easily obtained from spirometry, may be used as a surrogate index of airway collapse.

Aged↗
PubMed2001

Collapsing focal segmental glomerulosclerosis following treatment with high-dose pamidronate.

Collapsing focal segmental glomerulosclerosis (FSGS) is a distinct clinicopathologic entity seen most commonly in young African American patients who present with renal insufficiency and nephrotic syndrome. The only epidemiologic factor previously linked to collapsing FSGS is HIV infection. Here clinicopathologic findings are reported for a distinctive population of seven patients, who were older, Caucasian, and HIV negative and developed collapsing FSGS during active treatment of malignancy (multiple myeloma in six patients and metastatic breast carcinoma in one). Although oncologic treatment regimens included vincristine for four patients, doxorubicin for five patients, cisplatin for two patients, and total-body irradiation for one patient, the only agent common to all patients was pamidronate (Aredia). All patients had normal renal function before the administration of pamidronate. Patients began therapy with pamidronate at or below the recommended dose of 90 mg, intravenously, monthly, which was increased to 180 mg monthly in two patients and 360 mg monthly in three patients. Patients received pamidronate for 15 to 48 mo before presentation with renal insufficiency (mean serum creatinine, 3.6 mg/dl) and full nephrotic syndrome (mean 24-h urinary protein excretion, 12.4 g/d). Pamidronate, which is a member of the class of bisphosphonates, is widely used in the treatment of hypercalcemia of malignancy and osteolytic metastases. At the recommended dose of 90 mg, intravenously, monthly, renal toxicity is infrequent; however, higher doses have produced nephrotoxicity in animal models. The temporal association between pamidronate therapy and the development of renal insufficiency, the use of escalating doses that exceed recommended levels, and the distinctive pattern of glomerular and tubular injury strongly suggest a mechanism of drug-associated podocyte and tubular toxicity. These data provide the first association of collapsing FSGS with toxicity to a therapeutic agent.

Aged↗
PubMed1994

Prediction of collapse with magnetic resonance imaging of avascular necrosis of the femoral head.

In order to predict the probability of collapse of a femoral head in which there is avascular necrosis, we used magnetic resonance imaging to evaluate sixty-six hips (fifty patients) in which avascular necrosis was in the early stages and in which collapse of the head was not yet visible. The hips were followed radiographically for an average of forty-nine months (range, sixteen to eighty-four months), and with magnetic resonance imaging for an average of forty-four months (range, twelve to seventy-three months). Twenty-one (32 per cent) of the femoral heads had collapsed by thirty-two months. Of the twenty-three femoral heads in which necrosis involved at least one-fourth of the diameter of the head and encompassed at least two-thirds of the major weight-bearing area, seventeen (74 per cent) had collapsed by thirty-two months.

Adult↗
PubMed2006

Posterior rotational osteotomy for nontraumatic osteonecrosis with extensive collapsed lesions in young patients.

BACKGROUND: In young patients with nontraumatic femoral head osteonecrosis with extensive and collapsed lesions, joint preservation is a goal if total joint arthroplasty is to be avoided. We evaluated the effectiveness of a posterior rotational osteotomy in this patient population. METHODS: We reviewed thirty-five hips in twenty-eight young patients with nontraumatic femoral head osteonecrosis treated by posterior femoral neck rotational osteotomy. All femoral heads were collapsed, and seven hips showed joint-space narrowing. Lateral radiographs of the femoral head revealed that 15% of the mean posterior portion and 17% of the mean anterior portion of the femoral head consisted of radiographically apparent living bone. The mean age of the patients (ten women and eighteen men) was twenty-eight years. The mean follow-up period was eight years. RESULTS: Less than six months after surgery, the radiographically apparent area of living bone of the femoral head below the acetabular roof was shown to be 59% on the standard anteroposterior radiograph and 54% on the 45 degrees -flexion radiograph. In thirty-three hips (94%), further collapse of the femoral head was prevented and an adequate amount of living bone was demonstrated on the loaded lateral portion of the femoral head on the final follow-up radiographs. Progressive joint-space narrowing was seen in four hips. CONCLUSIONS: In young patients with osteonecrosis and extensively collapsed lesions of the femoral head, posterior femoral neck rotational osteotomy appears to be effective in delaying the progression of degeneration if an adequate area of living bone can be placed under the loaded lateral portion of the acetabulum. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adolescent↗
PubMed2000

Injury toll following the 1997 Maccabiah Games bridge collapse: implications of major disasters for sports medicine teams.

A major disaster was encountered at the 1997 Maccabiah Games in Israel. As the Australian team was about to enter the main stadium for the opening ceremony, a pedestrian bridge they were crossing collapsed, killing 4 athletes and injuring many others. The aim of this paper is to establish the rates, types and anatomical locations of musculoskeletal injuries incurred by members of the Australian Maccabiah Games team, with particular reference to the impact of the bridge collapse. In total, the 410 members of the team (360 athletes and coaches and 50 team officials) reported 166 injuries from their participation in sport and 30 musculoskeletal injuries associated with the collapse of the bridge. The most common sports-related injuries were sprains and strains to the hip/thigh, lumbar spine and ankle/foot regions, while the bridge collapse resulted in, most commonly, sprains and contusions to the hip/thigh, knee, lower leg and ankle/foot regions. In addition, team members incurred many medical and psychological conditions. This paper makes several recommendations for sports medicine staff based on the experience of this significant sport disaster.

Accidents↗
PubMed1989

Bronchial impaction in lobar collapse: CT demonstration and pathologic correlation.

Bronchial (or mucoid) impaction refers to the accumulation of inspissated secretions (mucus and/or inflammatory products) within a bronchus, usually accompanied by bronchial dilatation. This process may be caused by abnormal mucociliary transport and excessive production of mucus. In other cases, a discrete lesion may be present that obstructs the bronchus with inspissated secretions accumulating distal to the obstructing lesion. Lobar collapse may result in either case if a lobar bronchus is occluded by the excessive mucus or a discrete obstructing lesion. The CT manifestations of bronchial impaction in four patients with lobar collapse are described. In two patients, the lobar collapse and distal bronchial impaction were produced by a central obstructing bronchogenic carcinoma, whereas the other two patients had an abnormal mucus accumulation without a discrete bronchial obstruction. On CT, the impacted bronchi, best seen on postcontrast images, appeared as relatively low-attenuation branching structures extending from the hilum peripherally into the more opaque enhancing atelectatic lung. In the three patients who had surgical resection of the involved lobe, pathologic examination confirmed the dilated bronchi, filled with mucus (one patient), fibrinopurulent exudate (one), or mucous plugs with Aspergillus hyphae (one). This unique pattern of impaction within a collapsed lobe should be recognized on CT and prompt a search for a possible central obstructing lesion.

Bronchi↗
PubMed1999

Acute osteoporotic vertebral collapse: open study on percutaneous injection of acrylic surgical cement in 20 patients.

OBJECTIVE: The aim of this study was to determine the efficacy of percutaneous vertebroplasty in treating painful spinal osteoporotic collapse. SUBJECTS AND METHODS: Twenty-three cases of vertebral collapse were evaluated with CT and MR imaging to determine osteoporotic origin and recent evolution. Percutaneous vertebroplasties were performed using CT guidance. The 20 patients included in the study (17 women, 3 men; 62-92 years old) had acute pain of less than 1 month's duration that hindered ambulation and required treatment with narcotic drugs. They underwent this procedure for analgesic purposes. The analogic visual scale of Huskisson was used for pain when scoring assessment. RESULTS: In 15 patients (75%), pain relief was complete within 24 hr after injection. Analgesic administration was stopped in 14 patients. Mild pain persisted in three (15%) of the remaining five patients. In one other patient (5%), crural pain was observed with cement leakage in the psoas muscle. In the fifth patient (5%), pain recurred after the patient was lifted. The pain was related to a new acute collapse of an adjacent vertebrae. CONCLUSION: Vertebroplasty for the treatment of osteoporotic vertebral collapse is a minimally invasive procedure that provides immediate pain relief and enables the patient to become quickly mobile.

Acrylic Resins↗
PubMed2000

Dynamic tracheal collapse as a cause of exercise intolerance in a thoroughbred.

A 2-year-old Thoroughbred filly was admitted to the hospital for evaluation of exercise intolerance. Resting videoendoscopic evaluation (i.e., while the horse was standing) of the nasopharynx and trachea revealed right arytenoid paresis and a tracheal defect that was 100 cm distal to the external nares. Surgery, consisting of a right prosthetic laryngoplasty, was performed. However, postoperative videoendoscopic evaluation revealed minimal abduction of the affected arytenoid cartilage. Dynamic videoendoscopic evaluation (i.e., while the horse was exercising) revealed the right arytenoid to be fixed in a submaximal position with no evidence of collapse into the airway. When the endoscope was positioned in the midcervical tracheal region, marked tracheal collapse was identified during exercise. Tracheal collapse can critically limit athletic function. Treatment of tracheal collapse depends on causative factors, the length of the trachea involved, and accessibility of the affected tracheal segment. The use of dynamic tracheal videoendoscopy should be considered in athletic horses with exercise intolerance in which the cause cannot be determined from resting or dynamic videoendoscopic evaluations of the nasopharynx.

Animals↗
PubMed2002

Use of intraluminal nitinol stents in the treatment of tracheal collapse in a dog.

Tracheal collapse is a common problem that is typically observed in middle-aged and older small-breed dogs. It is a structural, obstructive airway disease with a dynamic component that can affect the intra- and extrathoracic portions of the trachea and mainstem bronchi. Many methods of treatment have been suggested, including medical management and provision of extraluminal and intraluminal support. All techniques used to treat intrathoracic and mainstem bronchial collapse have been associated with major complications or limitations. This report describes the implantation of intraluminal nitinol stents to successfully treat intrathoracic as well as extrathoracic tracheal collapse in a dog. The stents are composed of material that has characteristics similar to those of the trachea; nitinol stents may provide a method of supporting intrathoracic tracheal and mainstem bronchial collapse in dogs.

Alloys↗
PubMed1995

Perceptual collapse of three-dimensional structure from motion parallax.

This study concerned how perceived depth collapses after asymptotic depth is reached and the information specifying depth is abruptly removed. The stimuli were random-dot, computer-generated three-dimensional objects and the depth information was motion parallax. Motion parallax was removed in two ways. In the first method, the depth of all object points was reassigned to zero, simulating a disk. In the second method, a rotation of the object was introduced in such a way that a degenerate case of motion parallax was produced. The results showed that judgments of depth slowly collapsed once motion parallax was removed. Over-all, judgments of depth required about the same duration to collapse as was required for the judgments to build up to asymptotic levels (about 750 msec.). Finally, depth collapsed more slowly when the motion parallax was removed by redefining the object as a disk than when removed using the other method.

Computer Simulation↗
PubMedDate not supplied

Epidemiologic assessment of mortality, building collapse pattern, and medical response after the 1992 earthquake in Turkey. Disaster Reanimatology Study Group (DRSG).

BACKGROUND: Post-earthquake engineering and epidemiologic assessments are important for the development of injury prevention strategies. This paper describes mortality and its relationship to building collapse patterns and initial medical responses following the 1992 earthquake in Erzincan, Turkey. METHODS: The study consisted of: 1) background data collection and review; 2) design and implementation of a field survey; and 3) site inspection of building collapse patterns. The survey included: 1) national (n = 11) and local (n = 17) officials; 2) medical and search and rescue (SAR) workers (n = 38); and 3) a geographically stratified random sample of lay survivors (n = 105). The survey instruments were designed to gather information regarding location, injuries, initial actions and prior training of survivors and responders, and the location, injuries, and management of dead and dying victims. A case-control design was constructed to assess the relationship between mortality, location, and building collapse pattern. RESULTS: There was extensive structural damage throughout the region, especially in the city where mid-rise, unreinforced masonry buildings (MUMBs) incorporating a "soft" first floor design (large store windows for commercial use) and one story adobe structures were most vulnerable to collapse. Of 526 people who died in the city, 87% (n = 456) were indoors at the time of the earthquake. Of these, 92% (n = 418) died in MUMBs. Of 54 witnessed deaths, 55% (n = 28) of victims died slowly, the majority of whom (n = 26) were pinned or trapped (p < 0.05). Of 42 MUMB occupants identified through the survey, those who died (n = 25) were more likely to have been occupying the ground floor when compared with survivors (n = 28) (p < 0.01). Official medical and search and rescue responders arrived after most deaths had occurred. Prior first-aid or rescue training of lay, uninjured survivors was associated with a higher likelihood of rescuing and resuscitating others (p < 0.001). CONCLUSIONS: During an earthquake, MUMBs with soft ground floor construction are highly lethal, especially for occupants on the the ground floor, suggesting that this building type is inappropriate for areas of seismic risk. The vulnerability of MUMBs appears due to a lack of lateral force resistance as a result of the use of glass store front windows and the absence of shear walls. The prevalence of this building type in earthquake-prone regions needs to be investigated further. A large portion of victims dying in an earthquake die slowly at the scene of injury. Prior public first-aid and rescue training programs increase participation in rescue efforts in major earthquakes and may improve survival.

Architecture↗