PubMed Health⌕ Search

Biomedical subjects

A S Estrera

Publications and source records attributed to A S Estrera.

At least 19 recordsLinked to original sources
PubMed1996

Temporal course of gas exchange and mechanical compensation after right pneumonectomy in immature dogs.

To determine the temporal progression and magnitude of functional compensation in immature dogs raised to maturity after extensive lung resection, we performed right pneumonectomy (R-Pnx) or right thoracotomy without pneumonectomy (Sham) in matched foxhounds at 2 mo of age. At 4, 8, 20, 40, and 60 wk after surgery, static transpulmonary pressure-lung volume relationships were determined. Lung diffusing capacity, membrane diffusing capacity, pulmonary capillary blood volume, pulmonary blood flow, septal lung tissue volume, and lung volumes were measured simultaneously by a rebreathing technique. During maturation, total lung capacity, lung volume at a given distending pressure, and compliance were lower in the R-Pnx group than in the Sham group (P < 0.05). Pulmonary viscous resistance at maturity was elevated after R-Pnx. There were no significant differences in total lung diffusing capacity, membrane diffusing capacity, pulmonary capillary blood volume, pulmonary blood flow, and septal lung tissue volume between groups. Compensation of alveolar-capillary gas exchange was complete by 4-8 wk after R-Pnx, but compensation of mechanical properties remained incomplete throughout maturation. Relative magnitude of compensation after R-Pnx was greater in immature dogs than in adult dogs studied previously by similar techniques.

Airway Resistance↗
PubMed1993

Respiratory muscle limitation in patients after pneumonectomy.

Exercise capacity is significantly impaired in postpneumonectomy patients who have relatively normal remaining lungs. Our objectives are to determine (1) the nature and extent of mechanical ventilatory abnormalities and oxygen cost of breathing in such patients, and (2) the efficacy of a selective respiratory muscle training program in improving ventilatory and exercise performance. A group of eight postpneumonectomy and eight normal subjects (mean ages 59 and 50 yr, respectively) were studied during steady-state exercise and resting voluntary hyperventilation. Ventilation, work of breathing, cardiac output, and oxygen costs of breathing were determined. Four postpneumonectomy and five normal subjects were studied before and after a respiratory muscle training program. In patients after pneumonectomy compared with normal control subjects, maximal oxygen uptake (VO2) was 56% lower (p < 0.001). Work of breathing was significantly higher at a given ventilation. Mechanical efficiency of ventilation was lower by 44% (p < 0.05). Near maximal VO2, 48% of any additional increment of total-body VO2 was required to sustain the associated increment in ventilatory work, compared with 28% in normal subjects (p < 0.05), suggesting that competition between respiratory and nonrespiratory muscles for oxygen delivery is a significant factor limiting exercise after pneumonectomy. After respiratory muscle training, maximal respiratory pressures improved but maximal sustained ventilation and maximal VO2 did not improve significantly, suggesting that selective respiratory muscle training is of limited utility in postpneumonectomy patients.

Analysis of Variance↗
PubMed1992

Cardiac valve reconstruction and replacement: a brief review.

Surgical methods for improving the function of diseased cardiac valves are valve reconstruction (valvuloplasty) and valve replacement with mechanical prostheses, biologic prostheses, or homograft (donor) valves. Reconstruction is used primarily for incompetent mitral and tricuspid valves and addresses each part of the valve apparatus individually. Annuloplasty rings are often used to restore the size and shape of the valve orifice. Long-term anticoagulation therapy is not necessary. The designs of mechanical prostheses have evolved since the early caged-ball prostheses. Current models are noted for their durability. Patients who undergo implantation of these prostheses must also undergo long-term anticoagulation therapy. Biologic prostheses made from porcine valves or bovine pericardium are not as durable as their mechanical counterparts, but they do not require long-term anticoagulation therapy. Homografts are used in relatively few centers. They have good hemodynamics and do not necessitate long-term anticoagulation therapy. Radiologists should be familiar with the radiographic appearance of the various valve prostheses and annuloplasty rings and with the advantages and disadvantages of their use in cardiac valvular surgery.

Bioprosthesis↗
PubMed1992

Recruitment of diffusing capacity with exercise in patients after pneumonectomy.

Patients after pneumonectomy are severely limited upon exercise, but impairments in gas exchange are generally mild. One potential explanation of this observation is the existence of functional reserves of diffusing capacity (DLCO), which may be recruited during exercise, predominantly by increasing pulmonary blood flow (Qc). After pneumonectomy, DLCO reserves are recruited even at rest. To investigate if the pattern of recruitment of DLCO is altered and if reserves of DLCO are exhausted during exercise after pneumonectomy, DLCO, lung volume, and cardiac output were measured by the rebreathing method at rest and at multiple levels of steady-state exercise in eight subjects after pneumonectomy and in eight age- and sex-matched nonsmoking normal subjects. In patients after pneumonectomy, the slopes of increase in DLCO [ml.(min.mm Hg)-1.m-2] with respect to QC [ml.min-1.m-2] were normal (0.91 +/- 0.09 x 10(-3) in the pneumonectomy group, 1.16 +/- 0.12 x 10(-3) in the control group, mean +/- SE, p less than 0.05). Thus, the pattern of DLCO recruitment was not significantly affected by pneumonectomy. The ratio of DLCO/Qc fell more rapidly during exercise in patients after pneumonectomy, but the lowest value of the ratio achieved was relatively normal in all except one patient. Declines in arterial O2 saturation at exercise were mild and insufficient to explain the exercise limitation except in the patient whose DLCO/Qc fell below normal. There was no evidence that an upper limit of recruitment was approached. We conclude that the normal ability to recruit DLCO during exercise after pneumonectomy constitutes an important compensatory feature that prevents significant arterial O2 desaturation. In most patients, exercise is limited by a reduced maximal stroke index before reserves of diffusing capacity are exhausted.

Adult↗
PubMed1990

Systemic arterial air embolism in penetrating lung injury.

Systemic arterial air embolism is frequently unrecognized as a cause of death among patients with isolated penetrating lung injury. Between 1975 and 1983 at Parkland Memorial Hospital, the complication of systemic arterial air embolism developed in 9 patients with penetrating lung injury (six gunshots and three stabbings). Eight patients were either in profound shock or experienced cardiac arrest and all were intubated and on positive-pressure ventilation, frequently on a manual resuscitator bag before or at the time of diagnosis. The diagnosis was made by direct visualization of air in the coronary vessels in all 9 patients, and in 3 air was also aspirated from the left ventricular apex and aortic root. In addition, 5 patients had clinically significant hemoptysis. At operation, only an isolated injury to the lung was found in 7 of the 9 patients. Arterial air embolism is a highly lethal complication; 6 of our patients died, a mortality rate of 66%. Thus, it clearly behooves us to be more alert to the possible occurrence of this complication among all victims of penetrating chest trauma. We must accept that systemic arterial air embolism is an established complication of penetrating lung injury and must recognize that it occurs much more frequently than has been previously reported. Prompt diagnosis coupled with aggressive efforts at cardiopulmonary resuscitation is crucial for successful management of patients with air embolism.

Adolescent↗
PubMed1990

Apparatus seen on chest radiographs after cardiac surgery in adults.

The authors review the purpose, radiographic appearance, and possible complications of various tubes, catheters, and wires seen on chest radiographs after cardiac surgery. Drainage tubes, temporary epicardial wire electrodes, surgical clips, intraaortic counterpulsation balloon, atrial pressure monitor catheters, and sternal wires are reviewed. Because recent articles have discussed the Swan-Ganz catheter and automatic implantable cardioverter defibrillator, these are not covered in depth.

Adult↗
PubMed1988

The effect of mannitol and dopamine on the renal response to thoracic aortic cross-clamping.

Postoperative renal failure and insufficiency are important complications of operations that require thoracic aortic cross-clamping. Successful application of pharmacologic methods to protect renal function would be clinically useful. The ability of mannitol and dopamine to prevent renal dysfunction in a canine model of thoracic aortic cross-clamping was studied. Twenty animals were divided into four equal groups, and all underwent thoracic aortic cross-clamping for 60 minutes. An intra-aortic infusion of saline (control), mannitol, dopamine, or mannitol plus dopamine was started before, and continued during, the period of aortic occlusion. Glomerular filtration rate was significantly depressed 60 minutes after clamp release, and although there was some recovery in treated animals 150 minutes after clamp release, it remained significantly decreased (52% to 73% of baseline values, p less than 0.01). Renal blood flow was significantly reduced 60 minutes after clamp release, and there was no recovery in any group at 150 minutes (38% to 56% of baseline values, p less than 0.01). No significant differences in osmolar clearance or fractional excretion of sodium were evident between groups. These data reveal that the profound reductions in glomerular filtration and renal blood flow induced by thoracic aortic cross-clamping were not attenuated by mannitol or dopamine and suggest that efforts to protect renal function should be directed toward improving renal blood flow in the post-clamp period.

Acute Kidney Injury↗
PubMed1987

Management of esophageal gunshot wounds.

The records of 20 patients with gunshot wounds of the esophagus seen from 1973 through 1985 were reviewed. Nine perforations were cervical, 10 were thoracic, and 1 was abdominal. Because physical findings and plain roentgenograms lack specificity, a high index of suspicion based on the path of the bullet tract is essential for early diagnosis. Esophageal injury should especially be suspected when the bullet wound is transcervical or transmediastinal. Perforation was diagnosed by esophagoscopy in 9 patients, esophagography in 4, and surgical exploration in 7. Mean time from admission to operation was 3.8 hours. Associated injuries occurred frequently. Eighteen patients were treated by primary closure and wide drainage, and 2 were managed by esophageal exclusion. There were 2 perioperative deaths, both in patients with associated aortic injuries, and 1 late death, for an overall mortality of 15%. There was one postoperative leak following a cervical repair. No leaks occurred in patients having a thoracic repair. The findings indicate that esophageal perforation must be sought by a variety of methods. With prompt diagnosis and early operation, primary repair can be safely accomplished. When sepsis from esophageal leak is avoided, mortality and major morbidity are related to associated injuries.

Adult↗
PubMed1987

Mediastinal carinal bronchogenic cyst: is its mere presence an indication for surgical excision?

A notion has prevailed that carinal bronchogenic cyst and other congenital mediastinal cystic lesions, particularly those occurring in older children and adults, are usually asymptomatic, innocuous, and frequently only an incidental finding on routine chest roentgenogram or postmortem examination. Some physicians, therefore, have adopted a policy of observation for these patients. Our experience, however, as demonstrated in three cases reported herein, and the experience of others, clearly shows that carinal bronchogenic cyst is far from being usually asymptomatic and innocuous, but in fact often produces a broad spectrum of clinical manifestations, some of which are life-threatening. Mere observation not only places these patients at serious risk, but also increases the possibility of missed diagnosis and delayed treatment of those lymphoproliferative malignancies involving mediastinal lymph nodes that can mimic a carinal bronchogenic cyst. Computerized tomography (CT) is the single most important method of making a diagnosis of carinal bronchogenic cyst. We believe strongly that the mere presence of a mediastinal carinal bronchogenic cyst is an indication for surgical excision.

Adolescent↗
PubMed1985

Blunt traumatic rupture of the right hemidiaphragm: experience in 12 patients.

In a 9-year period (1972 to 1981), 35 patients with blunt traumatic rupture of the diaphragm were seen in our institution; 12 had involvement of the right hemidiaphragm, an incidence of approximately 34%. In 9 of these 12 patients, the right-sided diaphragmatic injuries were seen soon after the accident (acute), and in 3, late after the accident (chronic). A large diaphragmatic rent, usually 10 cm or more, without any predilection to a specific area of the right hemidiaphragm, was a frequent operative finding. Expectedly, the most common viscus that was injured or herniated through the defect was the liver. Total or nearly total herniation of the liver was noted in 5 patients and partial herniation, in 1. Injury to the juxtahepatic vena cava or hepatic vein, or both, was also encountered in 5 patients. This highly lethal injury accounted for the 3 deaths in the series, all of which were directly related to an uncontrollable exsanguinating hemorrhage from the injured vena cava or hepatic vein. The surgical approach for repair of a ruptured right hemidiaphragm is best individualized. The right thoracotomy approach through a right posterolateral incision is preferred for chronic diaphragmatic injury. It is also our choice in patients in whom acute right-sided injuries are definitively diagnosed and who are hemodynamically stable. This approach not only provided the best exposure of the defect, but also made the repair of associated retrohepatic caval injury surprisingly easy in at least 2 of our patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1984

Measurement of aortic root size by biplane angiography before cardiac valve replacement.

Aortic valve replacement (AVR) in the patient with a small aortic root demands special consideration because the hemodynamic function of artificial valves with a small external diameter is often poor. In this study, the internal diameter of the aortic root was measured from biplane ventriculography. This measured root diameter was then used to predict the external diameter of the artificial valve. Twelve patients underwent biplane ventriculography followed by AVR with Carpentier-Edwards bioprostheses. The artificial valve diameter was predicted with a correlation coefficient of 0.93, a standard error of estimate of 0.89 mm, and an average absolute difference between preoperative measurement and valve diameter of 0.69 mm. Therefore, the aortic root diameter can be accurately measured from the ventriculogram, thus detecting the patient with a small aortic root before surgery.

Angiography↗
PubMed1984

Management of acute cardiac trauma.

It is estimated that approximately 165,000 people die of traumatic causes every year. Thoracic trauma accounts for 25 per cent of all these traumatic deaths, and primary cardiac injury is a major contributing cause. Thus, every member of a trauma team must have a thorough knowledge of the diagnosis and management of cardiac injuries--penetrating and blunt--to effect an improvement in the overall survival of this group of trauma patients.

Cardiac Tamponade↗
PubMed1983

Descending necrotizing mediastinitis.

From January 1975 through July 1981, ten patients with mediastinitis complicating an oropharyngeal infection, that is, a form of mediastinitis best termed as DNM, were encountered at our institution. Based upon rather relatively stringent diagnostic criteria, 21 other instances were found in the literature from 1960 to 1980, a time period well into the antibiotic era. The predominant underlying oropharyngeal infection was of odontogenic origin, specifically, infection involving the mandibular molars. Bacteriologically, DNM is most frequently a polymicrobial process, with anaerobes playing a major role. Although there has been a decline in the over-all incidence of DNM since the introduction of antibiotics, its morbid and lethal nature persists, as evidenced by the present prohibitive mortality of approximately 42 per cent. Delayed diagnosis and inadequate drainage procedures are the primary underlying factors contributing to this high mortality. At present, CT scan is the single most important tool for the early diagnosis of DNM. This noninvasive procedure also helps determine the adequacy of the surgical drainage procedure performed. However, with all the presently available diagnostic tools, it is still the high index of suspicion by physicians toward patients with unrelenting oropharyngeal or deep neck infection that is of utmost importance for making an early diagnosis of DNM. In view of our experience and that of others, we believe that only through aggressive combined medical and surgical management can the highly morbid, if not lethal, course of DNM be reversed. It should be emphasized that, to accomplish successful operative intervention, a thorough knowledge of the complex anatomy of the region is crucial.

Abscess↗
PubMed1982

Massive pulmonary embolism: a complication of the technique of tourniquet ischemia.

Various neurologic and vascular injuries complicating the technique of tourniquet ischemia for limb surgery are well known. We found no reports of the serious complication of massive pulmonary embolism as a consequence of this technique. This is surprising when one considers the type of patients surgeons deal with in the use of the technique of tourniquet ischemia. These patients are traumatized and immobile, with high potential for development of deep venous thromboembolic disease, and are subjected to extensive extremity manipulation. Such patients are ideal candidates for the development of massive pulmonary embolism. We have encountered and successfully treated a patient with such a complication.

Adolescent↗
PubMed1981

Pulsatile sternal tumor: report of three cases and a review of the literature.

At our institution, 3 patients with pulsatile sternal tumor have been seen. Although ascending aortic aneurysm frequently is high on the list of differential diagnoses, the likelihood that this tumor is metastatic from either a primary renal or thyroid neoplasm is overwhelming. Of the 15 patients reported, 11 had metastases from a primary renal cell carcinoma, including all 3 of our patients. There were 2 patients with primary myeloma, the only histologically proved primary pulsatile sternal tumor. From the surgical standpoint, only the patient with metastatic renal cell carcinoma has a chance of cure. With the recent report of 2 5-year survivors and our own experience of 1 patient with a long asymptomatic interval following resection of the primary kidney tumor and the secondary sternal metastasis, the attitude of hopelessness for these patients should be challenged and an aggressive approach considered.

Adult↗
PubMed1981

Missile embolus to the lung associated with a corotid-jugular arteriovenous fistula.

Missile embolization to the pulmonary artery is rare. The diagnosis is suspected if a missile is seen on radiograph in a lung field without hemopneumothorax or pulmonary contusion. Treatment of the injury and embolic sites is indicted. We report a case of missile embolization to the lung associated with a carotid-jugular arteriovenous fistula.

Adult↗