Spaced learning versus massed learning in resuscitation - A systematic review

AIM

Skill decay is a recognised problem in resuscitation training. Spaced learning has been proposed as an intervention to optimise resuscitation skill performance compared to traditional massed learning. A systematic review was performed to answer 'In learners taking resuscitation courses, does spaced learning compared to massed learning improve educational outcomes and clinical outcomes?'

METHODS

This systematic review followed the PRISMA guidelines. We searched bibliographic databases (Embase, MEDLINE and the Cochrane Library (CENTRAL)) from inception to 2 December 2019. Randomised controlled trials and non-randomised studies were eligible for inclusion. Two reviewers independently scrutinized studies for relevance, extracted data and assessed quality of studies. Risk of bias of studies and quality of evidence were assessed using RoB, ROBINS-I tool and GRADEpro respectively. Educational outcomes studied were skill retention and performance 1 year after completion of training; skill performance between completion of training and 1 year; and knowledge at course conclusion. Clinical outcomes were skill performance at actual resuscitation, patient survival to discharge with favourable neurological outcome. This systematic review was registered in PROSPERO (CRD42019150358).

RESULTS

From 2,042 references, we included data from 17 studies (13 randomised studies, 4 cohort studies) in courses with manikins and simulation in the narrative synthesis. Eight studies reported results from basic life support training (with or without automatic external defibrillator); three studies reported from paediatric life support training; five were in neonatal resuscitation and one study reported results from a bespoke emergency medicine course which included resuscitation teaching. Fifteen out of seventeen studies reported improved performance with the use of spaced learning. The overall certainty of evidence was rated as very low for all outcomes primarily due to a very serious risk of bias. Heterogeneity across studies precluded any meta-analyses. There was a lack of data on the effectiveness of spaced learning on skill acquisition compared to maintaining skill performance and/or preventing skill decay. There was also insufficient data to examine the effectiveness of spaced learning on laypeople compared to healthcare providers.

CONCLUSIONS

Despite the very low certainty of evidence this systematic review suggests that spaced learning can improve skill performance at 1 year post course conclusion and skill performance between course conclusion and 1 year. There is a lack of data from this educational intervention on skill performance in clinical resuscitation and patient survival at discharge with favourable neurological outcomes.

Detection of indoxyl sulfate levels in dogs and cats suffering from naturally occurring kidney diseases

Indoxyl sulfate (IS), a protein-bound uraemic toxin, has been found to accumulate in the serum of people with renal diseases and is associated with free radical induction, nephrotoxicity cardiovascular toxicity, and osteoblast cytotoxicity. Although IS has been studied in humans and in experimental models, the role of IS in dogs and cats with kidney disease has not been investigated. A high performance liquid chromatography system was applied to detect plasma IS concentrations in non-azotaemic animals (63 dogs, 16 cats) and in animals with renal azotaemia (66 dogs, 69 cats). The IS levels of azotaemic animals were significantly higher (P <0.01) than those of non-azotaemic animals (median [IQR] 20.4 (9.5) mg/L vs. 7.2 (8.8) mg/L for dogs; median [IQR] 21 (18.9) mg/L vs. 14.8 (12.3) mg/L for cats). The IS level was significantly correlated with blood urea nitrogen, serum creatinine and phosphate concentrations. Dogs with acute kidney injury had significantly higher IS levels (P <0.01) than those with chronic kidney diseases (CKD) (median [IQR] 57.7 (40.8) mg/L vs. 17.7 (25.1) mg/L). When CKD was graded using the International Renal Interest Society (IRIS) staging system, IS levels were correlated with CKD severity in both dogs and cats. The IS concentration is directly related to loss of renal function. Further studies are necessary to determine whether measurement of IS provides any additional diagnostic or prognostic information in dogs and cats with kidney disease.

Epstein-Barr virus BGLF4 kinase retards cellular S-phase progression and induces chromosomal abnormality

Epstein-Barr virus (EBV) induces an uncoordinated S-phase-like cellular environment coupled with multiple prophase-like events in cells replicating the virus. The EBV encoded Ser/Thr kinase BGLF4 has been shown to induce premature chromosome condensation through activation of condensin and topoisomerase II and reorganization of the nuclear lamina to facilitate the nuclear egress of nucleocapsids in a pathway mimicking Cdk1. However, the observation that RB is hyperphosphorylated in the presence of BGLF4 raised the possibility that BGLF4 may have a Cdk2-like activity to promote S-phase progression. Here, we investigated the regulatory effects of BGLF4 on cell cycle progression and found that S-phase progression and DNA synthesis were interrupted by BGLF4 in mammalian cells. Expression of BGLF4 did not compensate Cdk1 defects for DNA replication in S. cerevisiae. Using time-lapse microscopy, we found the fate of individual HeLa cells was determined by the expression level of BGLF4. In addition to slight cell growth retardation, BGLF4 elicits abnormal chromosomal structure and micronucleus formation in 293 and NCP-TW01 cells. In Saos-2 cells, BGLF4 induced the hyperphosphorylation of co-transfected RB, while E2F1 was not released from RB-E2F1 complexes. The E2F1 regulated activities of the cyclin D1 and ZBRK1 promoters were suppressed by BGLF4 in a dose dependent manner. Detection with phosphoamino acid specific antibodies revealed that, in addition to Ser780, phosphorylation of the DNA damage-responsive Ser612 on RB was enhanced by BGLF4. Taken together, our study indicates that BGLF4 may directly or indirectly induce a DNA damage signal that eventually interferes with host DNA synthesis and delays S-phase progression.

Salvage surgery after failed chemoradiotherapy in squamous cell carcinoma of the esophagus

AIMS

To investigate the survival benefit and preoperative risk factors for hospital mortality of salvage surgery in esophageal cancer patients who had locoregional residual/recurrent tumor after definitive chemoradiotherapy.

METHODS

We retrospectively reviewed the esophageal cancer patients who presented at our hospital from 1997 to 2004. Forty-seven patients who had squamous cell cancer and developed locoregional recurrent/persistent disease after primary definitive chemoradiotherapy were elected. Twenty-seven of them received salvage esophagectomy (group 1) and the other 20 underwent non-operative treatment only (group 2). In order to assess the surgery-related mobility and mortality in group 1, 191 patients who received neoadjuvant chemoradiotherapy followed by operation during the same time period were also enrolled (group 3).

RESULTS

The 5-year overall survival of group 1 patients was 25.4%. In contrast, all of the patients in the group 2 died within 16.7 months. The difference was statistically significant (p=0.0029). In comparison with group 3, group 1 patients had significantly more surgery-related complications and hospital mortality. In univariate analysis for preoperative risk factors, a low albumin or hemoglobulin level was associated with high hospital mortality in group 1 (p=0.004 and 0.003, respectively). After multivariate analysis, only the low albumin level remained borderline significance. As for disease specific survival after salvage surgery, R0 resection was the only independent prognosticator (p=0.049).

CONCLUSION

Salvage surgery provides survival benefit in esophageal cancer patients with locoregional persistent or recurrent disease after primary definitive chemoradiotherapy. Preoperative albumin and hemoglobulin levels are associated with hospital mortality and may aid in selecting suitable patient for salvage surgery.

Levels of interferon-gamma and interleukin-2 receptor-alpha for bronchoalveolar lavage fluid and serum were correlated with clinical grade and treatment of pulmonary tuberculosis

OBJECTIVE

We investigated possible correlations for interferon-gamma (IFN-gamma) and soluble interleukin-2 receptor-alpha (sIL-2R-alpha) levels in bronchoalveolar lavage fluid (BALF), and clinical grade of pulmonary tuberculosis (TB), which is determined by factors such as extent of pulmonary involvement, fever and loss of body weight.

DESIGN

In order to explore these correlations and address associated questions, BALF was collected from 45 patients presenting with active pulmonary TB and 14 healthy controls. Repetitive BALF was collected in 17 patients after 3 months of anti-tuberculosis chemotherapy. The epithelial lining fluid (ELF) levels for IFN-gamma and sIL-2R-alpha were measured using enzyme-linked immunosorbent assay (ELISA) after standardization with urea.

RESULTS

Patients with higher-grade pulmonary TB (i.e., with more advanced pulmonary involvement, fever or body weight loss), revealed significantly higher ELF levels for IFN-gamma and sIL-2R-alpha compared to those with lower grade pulmonary TB. Similar results were also determined for sIL-2R-alpha serum levels, but not for IFN-gamma serum levels. After anti-tuberculosis chemotherapy the elevated cytokine levels for ELF and serum significantly decreased in accordance with radiographic improvement.

CONCLUSIONS

ELF levels of IFN-gamma and sIL-2R-alpha were correlated with disease grading of pulmonary TB and decreased after anti-tuberculosis chemotherapy.

Combined bronchoalveolar lavage and polymerase chain reaction in the diagnosis of pulmonary tuberculosis in smear-negative patients

SETTING

The polymerase chain reaction (PCR) may be sensitive and specific for the diagnosis of tuberculosis, but most reports are of studies conducted in well-controlled laboratories. A study to evaluate the clinical value of bronchoalveolar lavage (BAL) combined with PCR was necessary.

OBJECTIVE

One hundred and thirty one patients were recruited into the study from March 1994 to February 1997.

DESIGN

Patients with a positive acid-fast stain on sputum smear were recruited into group A as positive controls, patients with lung cancer and a negative acid-fast stain on sputum smear were put into group B as negative controls, and patients who had clinical symptoms of pulmonary TB without sputum or with negative smear results were the investigating group. PCR was performed on the sputum samples from group A and B patients and on the BAL fluid from those in group C.

RESULTS

The sensitivity of PCR was 96% in group A, and the specificity was 100% in group B. The sensitivity of PCR in the BAL fluid from the group C patients was 36% and the specificity was 96%; the positive predictive value was 94% and the negative predictive value was 45%.

CONCLUSION

BAL plus PCR is useful in the rapid diagnosis of pulmonary TB in non-productive or smear-negative patients.

Minimal access thoracic surgery for esophageal hemangioma

Esophageal hemangioma is a rare tumor. This report describes the case of a 69-year-old woman with an esophageal tumor at the middle portion of the esophagus. The patient was successfully treated with minimal access thoracic surgery, and at the 6 month follow-up, the patient was free of any symptoms or recurrence.

Paradoxical cerebral air embolism after removal of a central venous catheter: case report

Paradoxical cerebral air embolization through a residual tract after the removal of a central venous catheter is a serious complication of central venous cannulation. Air embolisms resulting from residual catheter tracts in general patients and in single lung transplant patients have been reported. The generally accepted mechanism of this complication is failure of a spontaneous collapse or thrombotic obliteration of a well-formed catheter tract. It may be related to the duration of catheter insertion, the patient's nutritional status, the diameter of the indwelling catheter, the upright position of the patient, deep inspiration or coughing, and improper wound dressing and catheter removal. Cardiovascular collapse, pulmonary or neurologic sequelae, and even death, are commonly noted in patients with air embolism. In this article, we report on cerebral air embolization as a complication with the removal with a central venous catheter in a patient with bullous emphysema. A high degree of suspicion and a prompt diagnosis are required for successful application of established therapy. Simple prophylactic procedures and constant awareness of the unusual mechanism of air embolism remain the best treatment.

Anomalous systemic arterialization to normal basal segments of the left lower lobe: helical CT and CTA findings

PURPOSE

The purpose of this work was to evaluate the helical CT and CT angiography (CTA) findings of anomalous systemic artery (ASA) to the basal segments of the left lower lobe (LLL).

METHOD

Three patients (two had hemoptysis, one was asymptomatic) with blotchy nodular density in the LLL revealed on chest radiographs underwent helical CT and CTA. Bronchoscopy was performed in two of these patients. Angiography and surgery were performed in one patient.

RESULTS

All three patients demonstrated characteristic helical CT and CTA findings including 1) a sigmoid-shaped ASA originating from the lower descending thoracic aorta, with a distal bulbous configuration and four arterial branches supplying the basal segments of the LLL; 2) absence of an interlobar pulmonary artery or presence of a small artery lateral to the truncus basalis; 3) engorged vascular markings in the basal segments of the LLL; and 4) normal tracheobronchial tree and lung parenchyma.

CONCLUSION

The findings in the present three cases suggest that the use of invasive studies such as angiography or bronchoscopy may be obviated in the diagnosis of ASA to the LLL because diagnosis can be provided through a clear set of criteria on helical CT and CTA.

Cost-effective approach of video-assisted thoracic surgery: 7 years experience

BACKGROUND

Cost containment is the driving force behind current health care reform. While video-assisted thoracic surgery (VATS) permits a less invasive approach to surgical diseases of the chest, cost is one aspect that is seldom discussed. In Asia, cost-effectiveness essential for the survival of this approach. We present our cost-effective experience with VATS in 2300 patients over a 7-year period.

METHOD

Between 1992 and 1999, 2300 patients underwent video-assisted thoracic surgery at Chang Gung Memorial Hospital. The mean age was 53.2 years (range, 22 days to 102 years); 67% (1541 patients) were men. The VATS technique was mainly performed based on traditional surgical principles. Conventional instruments and the fundamental surgical techniques of dissection, suturing, hemostasis, and tissue approximation that are familiar in the open setting were modified and used to enhance cost savings during VATS.

RESULTS

Surgery was performed on 41 patients on an emergency basis (24 with impending cardiac tamponade and 17 with hemothorax). The mean hospital stay of the patients treated by VATS was 4.5 days. The majority of the patients were operated on successfully using conventional instruments under video vision. The overall operative cost was decreased as compared to common VATS techniques. No delayed morbidity was noted in our patients after a mean follow-up period of 39 months (range, 1 to 68 months).

CONCLUSION

It is our experience that VATS procedures should be performed with the same expertise as open surgery. Conventional instruments similar to those used in open thoracotomy can be incorporated in VATS, and with a more natural hand manipulation. Only through stringent use of expensive endoscopic consumables and application of modified techniques based on traditional surgical principles can VATS be performed efficaciously and economically for a wide range of thoracic conditions.

Catamenial hemoptysis: report of a case treated with thoracoscopic wedge resection

Catamenial hemoptysis is a rare form of hemoptysis. It is a term for the condition of hemoptysis associated with menses. Few cases have been reported in the literature. Only one case, treated by video-assisted thoracoscopic wedge resection, has been described. We report the case of a 26-year-old woman who suffered from catamenial hemoptysis for 7 months and was treated successfully with a video-assisted thoracoscopic (VATS) wedge resection of the lesion. No evidence of recurrence was noted in the postoperative follow-up period of 48 months. We suggest that VATS is the good choice for single focus catamenial hemoptysis.

Pulmonary lymphangioleiomyomatosis in a 29-year-old woman with bilateral spontaneous pneumothorax: case report

Pulmonary lymphangioleiomyomatosis is a rare, progressive and fatal interstitial lung disease that affects women of child-bearing age. It is characterized by the nonneoplastic proliferation of atypical smooth muscle cells around lymphatics, venules, and bronchioles. Patients with pulmonary lymphangioleiomyomatosis most commonly present with exertional dyspnea and a cough. Pneumothorax is almost always found on the initial chest radiograph. We report a case of a 29-year-old woman who presented with abrupt right chest pain and progressive dyspnea. Physical examination in the emergency department was significantly diminished breath sounds over the right lung, and a chest X-ray revealed a right-sided pneumothorax. She required a chest tube for complete lung re-expansion. On the sixth day of admission, left-sided pneumothorax occurred and another chest tube was inserted. She underwent high-resolution computed tomography of the thorax with the findings of numerous cysts evenly distributed throughout the parenchyma of both lungs. Bilateral thoracotomy with lung biopsies and pleurodesis were performed and the surgical findings confirmed the presence of multiple, small, pink-colored cystic lesions on the surfaces of both lungs. Pathological examination showed the characteristic findings of pulmonary lymphangioleiomyomatosis.

Imbalances between tumor necrosis factor-alpha and its soluble receptor forms, and interleukin-1beta and interleukin-1 receptor antagonist in BAL fluid of cavitary pulmonary tuberculosis

OBJECTIVES

We investigated the possibility that the large pulmonary cavity in tuberculosis (TB) lesions might result from imbalances between tumor necrosis factor-alpha (TNF-alpha) and soluble TNF-alpha receptor forms (sTNF-RI and sTNF-RII), and interleukin-beta (IL-1beta) and IL-1 receptor antagonist (IL-1RA) in sites of local inflammation.

PATIENTS AND METHODS

BAL was performed in 32 patients with active pulmonary TB, and the recovered BAL fluid (BALF) was examined for concentrations of TNF-alpha and its soluble receptor forms, IL-1beta, and IL-1RA. Patients were classified into two groups: group 1, patients with a large cavity (> or = 4 cm) on chest radiographs (n = 15); and group 2, patients with a small cavity (< 4 cm; n = 3) or no cavity (n = 14) on chest radiographs.

RESULTS

The concentrations of TNF-alpha, IL-1beta, and IL-1RA in BALF were significantly higher in group 1 patients than in group 2 patients before standardization. The difference was also statistically significant for TNF-alpha and IL-1beta after standardization with urea. Furthermore, group 1 patients had significantly higher ratios of TNF-alpha to sTNF-RI and sTNF-RII and IL-1beta to IL-1RA compared with group 2 patients.

CONCLUSIONS

These findings suggest that the relative abundance of TNF-alpha and IL-1beta associated with imbalances of secretion of soluble TNF-alpha receptor forms and IL-1RA may have caused tissue necrosis leading to cavity formation in patients with active pulmonary TB.

MRI of thoracic vascular lesions with emphasis on two-dimensional time-of-flight MR angiography

MRI is a valuable method for evaluating thoracic vascular lesions by virtue of its non-invasiveness and multiplanar capability. In addition, ionizing radiation and iodinated contrast medium are not required. Electrocardiographically gated T1 weighted spin echo MRI remains the principal technique for demonstrating the anatomy and morphology of thoracic vascular diseases. Cine MRI allows dynamic evaluation of vascular flow, whereas MR angiography is particularly useful in the two-dimensional (2D) or three-dimensional (3D) display of vascular anatomy. This pictorial review illustrates the use of 2D time-of-flight MR angiography in the assessment of various thoracic vascular conditions including aortic arch and great vessel anomalies, heterotaxic syndromes, aortic dissection, aortic or arch vessel aneurysms, pulmonary embolism, pulmonary sequestration, axillofemoral bypass and tumour/vessel relationships.

Coronary dissection and myocardial infarction following blunt chest trauma

Myocardial infarction (MI) following blunt chest trauma is rarely diagnosed because the ensuing cardiac pain is commonly attributed to contused myocardium or the traumatic injuries in the local chest wall. There are only scattered reports on the coronary pathology associated with MI secondary to blunt chest trauma. Because differentiation of the pathology is difficult but important, we report here three cases of acute anterior MI secondary to coronary dissection following blunt chest trauma. Coronary dissection was demonstrated by coronary angiography. Two of the patients had intimal tears at the proximal left anterior descending artery (LAD) with normal flow, and the other patient had nearly total occlusion of the LAD associated with filling defects probably caused by an intracoronary thrombus. All three patients received conservative treatment without major complications and remained free from angina or heart failure throughout a 5-year follow-up period. In order to exclude associated MI in cases of blunt chest trauma, electrocardiography is necessary, and coronary angiography may be indicated to demonstrate coronary arterial pathology. Dissection of the coronary artery with subsequent thrombus formation is one of the possible pathophysiologic mechanisms of MI following blunt chest trauma.

Spontaneous variability of arterial oxygenation in critically ill mechanically ventilated patients

OBJECTIVE

To assess the magnitude of spontaneous variability of arterial oxygenation and oxygen tension-based indices over time in medical intensive care unit (ICU) patients and to study whether high positive end-expiratory pressure (PEEP) or inverse inspiratory-to-expiratory (I:E) ratio ventilation (IRV) results in a greater variability than low PEEP with conventional I:E ratio ventilation.

DESIGN

Prospective study.

SETTING

Medical ICU in a tertiary medical center.

PARTICIPANTS

23 patients requiring a pulmonary artery floating catheter for hemodynamic monitoring.

INTERVENTION

After being completely sedated, patients were randomized to receive pressure-control ventilation at setting A: high PEEP (15 cm H2O) with conventional I:E ratio (1:2) and setting B: inverse I:E ratio (2:1) with low PEEP (5 cm H2O) alternately, and then at setting C: low PEEP (5 cm H2O) with conventional I:E ratio (1:2). Each ventilation setting lasted 1 h.

MEASUREMENTS AND RESULTS

The arterial and mixed venous blood samples were measured simultaneously at baseline (time 0), and at 15, 30, 45, and 60 min thereafter. The coefficient of variation (CV) of arterial oxygen tension (PaO2) over time was 5.9 % for setting A, 7.2 % for setting B, and 6.9 % for setting C. ANOVA showed no significant differences in CVs of PaO2 between the three settings. Oxygen tension-based indices, alveolar-arterial oxygen difference (A-aDO2) and PaO2/ PAO2 (alveolar oxygen tension), displayed CVs equal to that of PaO2; the CV of A-aDO2/PaO2 was significantly greater than that of PaO2.

CONCLUSIONS

In critically ill medical ICU patients, despite sedation, the spontaneous variability in PaO2 over time is substantial. A high PEEP or IRV does not contribute to the increased variation in PaO2.

Serodiagnosis of tuberculosis by enzyme-linked immunosorbent assay for anti-A60 and anti-A38

BACKGROUND

For early diagnosis of tuberculosis (TB), especially in the patients without adequate sputum specimens for examination, we found a simple, rapid and inexpensive method among many current available diagnostic tools, the enzyme-linked immunosorbent assay (ELISA). To investigate the diagnostic effectiveness of this method, we applied ELISA for detection of antigen 60 IgG and IgM as well as antigen 38 IgG antibodies at Chang Gung Memorial Hospital from April 1995 through June 1996.

MATERIALS AND METHODS

Sixty-seven patients were enrolled and divided into 3 groups, Group A (n = 24), patients with positive sputum acid-fast stain; Group B (n = 18), patients with lung cancer and negative sputum acid-fast stain; and Group C (n = 25), patients with chest roentgenogram (CXR) which were suggestive of TB but with negative acid-fast stain results or no sputum for examination.

RESULTS

For the A60 IgG antibody, we found a sensitivity rate of 91.7% for Group A and Group B, and 85.7% for Group C as well as an overall sensitivity of 89.5% but with lower specificity. For the A60 IgM antibody, a lower sensitivity (37.5%, 14.3%, 28.9%, respectively) was found but with higher specificity. For the A38 IgG antibody, we found a lower sensitivity (40%, 11.1%, 31%, respectively) but with higher specificity (100%, 71.4%, 90%, respectively).

CONCLUSION

With a high sensitivity but low specificity for diagnosis of TB, A60 IgG ELISA could be used as a rapid, simple screening test for patients with results suggestive of TB, especially in those who had no sputum or had negative sputum acid-fast stain results. Otherwise, A60 IgM or A38 IgG ELISA, with a high specificity, could be used as a reliable test in the diagnosis of pulmonary TB when the result is positive. In summary, although ELISA is a simple, rapid, inexpensive method, it is helpful but limited in the diagnosis of pulmonary TB.

Thymic lymphoepithelioma-like carcinoma associated with thymoma in a patient with ocular myasthenia

A 65-year-old woman with ocular myasthenia was found to have three tumours in the anterior mediastinum, revealed by magnetic resonance imaging. All three lesions were radically resected. Histologically, one was a mixed-type thymoma, one a thymic lymphoepithelioma-like carcinoma, and the third had features of both these types. This appears to be the first reported case of coexisting thymic lymphoepithelioma-like carcinoma (TLC) and thymoma associated with ocular myasthenia.

Primary left atrial malignant mesenchymoma: a case report

Primary malignant mesenchymoma involving the heart is extremely rare. It usually has a poor prognosis. We report a case of malignant mesenchymoma originating in the left atrium with protrusion into the right pulmonary veins. Clinically, this patient presented with congestive heart failure, hemoptysis and systemic arterial embolization. Transthoracic and transesophageal echocardiography revealed a huge mass originating in the posterior wall of the left atrium with extension into both upper and lower right pulmonary veins. An elevated pulmonary arterial wedge pressure, moderate pulmonary hypertension and stenosis of the lower abdominal aorta were found during cardiac catheterization. Magnetic resonance imaging with angiography disclosed a tumor mass over the abdominal aorta above the bifurcation with protrusion into the right common iliac artery. This patient underwent surgical resection of the cardiac tumor and postoperative adjuvant chemotherapy. The pathological finding of a tumor containing several cellular types of sarcoma confirmed the diagnosis of malignant mesenchymoma.

Video-assisted thoracoscopic surgery for spontaneous hemopneumothorax

We operated on 403 patients with spontaneous pneumothorax between 1992 and 1996. Among these cases, 11 (2.7%) were spontaneous hemopneumothorax. The patients were all men, with ages ranging from 19 to 28 years (mean 23.8 years). The amount of blood drainage ranged from 650 to 2300 ml. Video-assisted thoracoscopic surgery was performed on these patients within 1 day after admission. The sources of bleeding were in the parietal and visceral pleurae of ruptured bullae (n = 6), the parietal pleura (n = 4), or the visceral pleura (n = 1). During operation, the ruptured bullae can be managed by an endoscopic linear stapler for a bullectomy, and the bleeding parietal pleura of the torn adhesion can be coagulated directly. Postoperative recovery of the 11 patients was uneventful, and they were discharged 4 to 10 days after the operation. No recurrence of spontaneous hemopneumothorax or any other complications occurred during follow-up. Thus spontaneous hemopneumothorax can be readily managed by cauterizing a bleeding site where appropriate, excising the apicocystic disease, and pleurodesis. As a minimally invasive method, video-assisted thoracoscopic surgery may be considered an initial treatment procedure in patients with spontaneous hemopneumothorax.

Thoracic neurilemomas: an analysis of computed tomography findings in 36 patients

On computed tomography (CT), neurilemomas have generically been described as well-defined, round masses with heterogeneous contrast enhancement. The CT scans of 38 surgically proven thoracic neurilemomas in 36 patients were reviewed to characterize further the CT features of this tumor, with an emphasis on different enhancement patterns. Unenhanced CT was available in 32 patients; 10 tumors appeared isodense, and 22 tumors appeared slightly hypodense compared with chest wall muscle. Except for an intraosseous neurilemoma of the T8 vertebral body, which mimicked bone metastasis, the tumors could be categorized into five different patterns on CT after contrast enhancement. Twenty tumors (54.1%) revealed diffuse, but amorphous and inhomogeneous enhancement. Seventeen (45.9%) tumors appeared as masses with multiple hypodense or cystic areas. Of these 17, the pattern was somewhat radial enhancement (n = 6, 16.2%), peripheral enhancement with a large central hypodense area (n = 5, 13.5%), homogeneous hypodensity (n = 5, 13.5%), and central enhancement with peripheral hypodensity (n = l, 2.7%). Appreciation of various CT manifestations is important in the diagnosis of this tumor.

Respiratory drive and pulmonary mechanics during haemodialysis with ultrafiltration in ventilated patients

The improvements of respiratory drive and pulmonary mechanics which follow haemodialysis with ultrafiltration in mechanically ventilated renal failure patients seem predictable but have not been studied before. In this study, 14 renal failure patients with stable haemodynamics mechanically ventilated with pressure support ventilation (PSV) were enrolled. Respiratory drive (represented as P0.1), pulmonary mechanics, breathing pattern, arterial blood gas and haemodynamics were measured according to the time schedule: pre-dialysis (Time 0), and at 60, 120, 180, 240 minutes thereafter. Following the removal of excess lung water during haemodialysis, auto-PEEP and patient's work of breathing (WOBp) decreased gradually. P0.1 lessened progressively along with the improvement in pulmonary mechanics. The changes in auto-PEEP and WOBp correlated closely to the pre- and post-dialysis decline of P0.1 (delta P0.1). There was a negative, moderately significant correlation between the amount of fluid ultrafiltrated during dialysis (delta UF) and the delta P0.1 (R = -0.54). The breathing pattern remained stable during dialysis. No hypoventilation or hypoxaemia occurred despite the development of metabolic alkalosis induced by bicarbonate dialysate. We have shown that respiratory drive decreases gradually during bicarbonate haemodialysis. The improvements of pulmonary mechanics, rather than the rapid alkalization of body fluids, responds to the decrease of P0.1 in renal failure patients ventilated with PSV.

Reconstruction of a large thoracoabdominal wall defect with a flow-through forearm flap and a latissimus dorsi-groin flap

We report a case of a 45-year-old man with a recurrent, large, invasive dermatofibrosarcoma protuberans over the left lower chest and abdomen. Wide surgical excision of the tumor created a major thoracoabdominal wall defect. Wound coverage was achieved by using a flow-through forearm flap and an inferiorly based latissimus dorsi-groin flap. Follow-up at 1 year revealed no local recurrence or herniation.

Continuous antegrade warm blood cardioplegia attenuates augmented coronary endothelium-dependent contraction after cardiac global ischemia and reperfusion

BACKGROUND

Experiments were designed to evaluate the effect of warm blood cardioplegia on endothelium-dependent contraction of the coronary endothelium after cardiac global ischemia and reperfusion.

METHOD

Dogs (n = 12 in each group) were exposed to extracorporeal circulation with the body temperature at 37 degrees C (group 1) or 28 degrees C (groups 2 and 3). The ascending aorta was crossclamped for 120 minutes while continuous infusion of warm blood cardioplegec solution (group 1) or intermittent infusion of cold (4 degrees C) crystalloid cardioplegic solution (group 2) was performed via the coronary arteries through the aortic root. Cardioplegic solution was not used in group 3 animals. The heart was then allowed to function for 60 minutes of reperfusion. Reperfused (groups 1, 2, and 3) and control (group 4) coronary arteries were then harvested for study.

RESULTS

Perfusate hypoxia caused endothelium-dependent contraction in the arteries of all four groups that could be attenuated by NG-monomethyl-L-arginine (L-NMMA) or L-NMMA plus D-arginine, but not by L-NMMA plus L-arginine or endothelin receptor A and B antagonist PD 145065. The endothelium-dependent contraction results in groups 2 and 3 (75% +/- 4% and 80% +/- 5%, respectively) were significantly greater than those in groups 1 and 4 (15% +/- 3% and 18% +/- 5%, respectively). Scanning electron microscope studies showed that platelet adhesion and aggregation, areas of microthrombi, disruption of endothelial cells, and separation of the intercellular junction could be found in coronary segments from groups 2 and 3, but not in vessels from groups 1 and 4.

CONCLUSION

These experiments suggest that global ischemia and reperfusion enhances hypoxia-mediated endothelium-dependent contraction of the coronary endothelium and damages the ultrastructure. These kinds of changes can be prevented by continuous antegrade infusion of warm blood cardioplegic solution during global ischemia.

Castleman's disease: a case report

Castleman's disease is a rare, benign disorder most commonly located in the mediastinum as a solitary mass. It is a lymphoid tissue disorder characterized by lymphoid proliferation. In this paper we describe a case of asymptomatic interlobar fissure tumor, localized Castleman's disease, hyaline vascular type, in a 30-year-old female. The tumor arose from the interlobar fissure between the right middle and lower lobes. Laboratory data revealed hypochromic microcytic anemia, similar to that found in iron deficiency, and an elevated erythrocyte sedimentation rate. She underwent video-assisted thoracic surgery for excision of the tumor. Anemia disappeared two months after surgery. No recurrence of the lung tumor was seen 19 months following surgery and she remains well.

Home-made endoloops for bullous lung disease: a case report

Various surgical techniques for bulla ablation have been used since the introduction of video-assisted thoracoscopic surgery. Endoscopic stapler resecting (Endo-GIA) is now the most common procedure for bulla ablation. Other endoscopic techniques include bulla suturing, clipping, laser ablation and electrocauterization. We present here a select report on using a "home-made" endoloop on a patient with bullous lung disease. No intraoperative morbidity was attributable to the procedure. The operating room time was 110 minutes, and ventilator support was given for 18 hours. The chest tube was removed on day 7 and the patient discharged on the ninth postoperative day uneventfully. The patient exhibited subjective improvement in his symptom preceptions during an one-month follow-up examination. A comparison of pre- and post operative functional evaluation showed increase in FEV1 (from 0.45 L to 1.02 L) during 3-month follow-up. From our experience, thoracoscopic home-made endoloop ligation is a safe and cost effective means of volume reduction surgery for bullous emphysema that interferes with optimum function of the adjacent lung parenchyma.

Transaortic patch angioplasty for left main coronary artery occlusion

Isolated total occlusion of the left main coronary artery is rare, and may be conventionally treated by standard bypass surgery. We describe a 54-year-old woman with isolated left main coronary artery disease presenting as unstable angina of 1 week's duration. She was treated with transaortic autologous pericardial patch angioplasty. Postoperative coronary angiography showed a widely patent left main coronary artery. She was angina-free 5 months postoperatively. In selected patients, this technique offers a valuable alternative to coronary artery bypass with the advantage of restoring more physiologic perfusion to the coronary tree.

An alternative technique in the management of bullous emphysema. Thoracoscopic endoloop ligation of bullae

STUDY OBJECTIVES

With the improvements in video-assisted thoracoscopic surgery, more older patients and patients with respiratory impairments are undergoing bulla ablation using new and costly technology. We evaluated the cost-effective technique of thoracoscopic endoloop ligation of bullae in patients with bullous emphysema.

PATIENTS

From March 1992 through January 1996, 79 advanced age (mean age, 64 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Only patients with radiographically confirmed diagnosis of bullous emphysema were included in this evaluation. Thoracoscopic endoloop ligation of bulla was carried out under general anesthesia with double-lumen endotracheal tube and single-lung ventilation.

RESULTS

Sixty-five patients (82%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the Modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 6 days (range, 4 to 16 days). Average hospital stay was 9.5 days (range, 5 to 26 days). There was no postoperative death. A comparison of preoperative and postoperative functional evaluation was available in only 16 patients who showed an increase in FEV1 (from 0.85 to 1.02 L) and a decline in residual volume after operation. Complications include persistent airleak over 10 days in seven patients (8.9%), wound infection in three patients, and localized empyema in two patients. There was no recurrence after a mean follow-up of 21 months.

CONCLUSION

These encouraging results have shown that thoracoscopic endoloop ligation of bulla has proved to be a safe, reliable, and cost-effective technique for bullous emphysema. With careful preoperative evaluation and meticulous postoperative care, many patients could be rehabilitated by endoloop litigation of the bullae.

MR imaging of thoracic neurilemmomas

Magnetic resonance (MR) imaging features of 15 thoracic neurilemmomas were analyzed. Morphologically, five tumor patterns could be identified on MR imaging including: inhomogeneous masses (n = 8), thick-walled multiloculated masses (n = 2), thick-walled central cystic masses (n = 2), homogeneous cystic masses (n = 2) and a target pattern mass (n = 1). The signal characterization of thoracic neurilemmomas was variable, usually brighter on T2-weighted images, hyper- to hypo-intense on T1-weighted images and always enhancing. Histopathologically, the inhomogeneous masses were characterized by irregular distribution of hypercellular Antoni A and hypocellular Antoni B tissues with variable degrees of cystic, hemorrhagic, myxoid and hyaline degenerative changes. Enlargement of the cystic areas led to the development of thick-walled multiloculated masses while confluence of these cystic areas produced a central cystic pattern. Extensive myxoid or hyaline degeneration yielded homogeneous cystic tumors. Peripheral fibrinous changes and central Antoni B stroma contributed to a target pattern. Appreciation of the protean MR manifestations and understanding of the underlying histopathological changes of thoracic neurilemmomas are helpful in the diagnosis of this tumor.

Thoracoscopic loop ligation of parenchymal blebs and bullae: is it effective and safe?

Surgeons who have gained experience and confidence with video-assisted thoracic surgery are now routinely applying the minimally invasive approach to treat patients with spontaneous pneumothorax. Although the endoscopic stapling device may be a preferred method for resection of parenchymal blebs or bullae, the stapling device is not inexpensive. In an effort to contain costs since we started performing the video-assisted thoracoscopic procedure in chest surgical diseases, we have used a self-made endoscopic loop as an alternative method. It has assisted us in performing bulla ablation in a cost-effective manner. Over a 4-year period (1992 to 1996), we assessed the efficacy of ligating parenchymal blebs and bullae with a self-made endoscopic loop by video-assisted techniques. A total of 263 ligations were performed in 250 patients. Surgical indications included recurrence (n = 146), bilaterality of the disease (n = 13), hemopneumothorax (n = 7), radiologically demonstrated large bulla (n = 9), persistent air leak (n = 52), and nonexpansion of the lung (n = 23). There were no operative deaths. Early postoperative complications included a dislodged endoscopic loop necessitating reexploration in one patient and postoperative minor wound infections in 13. The average postoperative hospitalization was 4.5 days. Two hundred seventeen patients (86.8% of all patients) were followed up for a median of 28 months (1 to 46 months) after the operation. There have been no recurrences to date. Our results showed that thoracoscopic loop ligation is safe and effective in managing blebs and parenchymal bullae, with a lower cost, fewer complications, and a lower recurrence rate than provided by standard surgical techniques. On the basis of our results, we advocate the use of the self-made endoscopic loop for ligation of parenchymal blebs and bulla in patients with spontaneous pneumothorax to achieve a truly cost-effective and minimally invasive thoracoscopic procedure.

Prolonged circulatory arrest in moderate hypothermia with retrograde cerebral perfusion. Is brain ischemic?

BACKGROUND

Circulatory arrest (CA), which provides a bloodless field and good visualization without the need of aortic cross-clamp, is commonly used to facilitate repair of aortic lesions. However, extended periods of CA may impair cerebral metabolism and cause ischemic injury. Studies were performed to evaluate the efficacy of retrograde cerebral perfusion (RCP) in protecting the brain from ischemic injury during a prolonged period of CA in moderate hypothermia.

METHODS AND RESULTS

Twenty-three patients (18 men and 5 women) were operated on for aortic lesions (17 acute type A aortic dissection and 6 chronic type A aortic dissection with Marfan's syndrome). The aortic operations were performed with CA (58 to 104 minutes; mean +/- SD, 75 +/- 12 minutes) at a rectal temperature of 23.3 +/- 0.5 degrees C (21 degrees C to 25 degrees C). For RCP, cold (14 degrees C to 18 degrees C) oxygenated blood (300 mL/min) was pumped to the superior vena cava with internal jugular venous pressure of 15 +/- 5 mm Hg. The cardiopulmonary bypass time was 157 +/- 18 minutes. Cortical blood flow during RCP detected by subdural laser Doppler probe was 10 +/- 5% of baseline. Percent oxygen extraction and pyruvate and lactate levels (26 +/- 2% and 0.43 +/- 0.17 and 45 +/- 16 mg/dI) were insignificantly different from those before CA (28 +/- 3% and 0.71 +/- 0.08 and 62 +/- 20 mg/dL, P > .05). Creatine kinase-BB isoenzyme was undetectable. All but 1 patient survived the operation (95.5%) and woke up without neurological deficit. Follow-up (mean, 13 months) was complete in all survivors. There were no late deaths. Cerebral functional studies performed 3 months after discharge showed results insignificantly different from those of the normal control subjects.

CONCLUSIONS

There is no evidence of ischemia of the brain during prolonged moderate hypothermic CA with the aid of RCP. Retrograde cerebral perfusion effectively extends the safe time of CA. Deep hypothermia during CA seems unnecessary.

Creutzfeldt-Jakob disease: clinical analysis of eight cases

BACKGROUND

Creutzfeldt-Jakob disease (CJD) or spongiform encephalopathy in humans, is a rare, rapidly progressive and fatal disorder of the central nervous system. Since clinical diagnosis is challenging, this retrospective investigation was performed.

METHODS

Eight cases who had been diagnosed as CJD from 1987 to 1995 were reviewed thoroughly, with a resulting clinical diagnosis of CJD. Two cases were proved by brain biopsy.

RESULTS

Four males and four females were included; their ages were 53 to 81 years with a mean of 66 years. The mean illness duration of the six patients who died was six and a half months. Clinical findings were variable and included dementia, aphasia, ataxic gait, pyramidal, extrapyramidal, myoclonus and visual problems.

CONCLUSIONS

For diagnosis of CJD, clinical suspicion is very important. Electroencephalogram (EEG) remains the most helpful laboratory diagnostic tool; serial recordings are necessary if the initial EEG finding is nonspecific. Single photon emission computed tomography (SPECT) may be helpful for premorten diagnosis of CJD, but sensitivity and specificity need further investigation. Brain biopsy seemed to be unnecessary if the clinical, EEG and SPECT findings are typical.

Identification of low molecular weight allergens of American cockroach and production of monoclonal antibodies

BACKGROUND

Previous studies have identified two allergic fractions (Cr-PI and Cr-PII) from crude American cockroach extract, from which the 72- and 78-kilodalton (kD) components of Cr-PI have been identified as major allergens.

OBJECTIVE

The objective of this study was to identify important allergens in Cr-PII and produce monoclonal antibodies.

METHODS

Sera of cockroach-sensitive atopic patients were examined for IgE binding to Cr-PII proteins and monoclonal antibodies were generated by fusion between spleen cells of BALB/c mice immunized with Cr-PII and FO cells.

RESULTS

Immunoblotting revealed that eight allergenic compounds in Cr-PII are able to bind specific IgE. Allergens of 18, 28, 32 and 45 kD bound 16.7% (2/12), 100% (12/12), 83.3% (11/12), and 100% (12/12) of the atopic sera tested, respectively. Cell fusion resulted in three stable subclones secreting monoclonal antibodies, and none of the monoclonal antibodies recognized any epitopes of German cockroach and Cr-PI of American cockroach. One monoclonal antibody reacted strongly with the 28- and 32-kD allergens of Cr-PII, and two monoclonal antibodies were able to bind the 18- and 12-kD components of Cr-PII with similar epitope specificities. All the epitopes defined by monoclonal antibodies are recognized by human IgE as demonstrated by a fluoroallergosorbent test (FAST) inhibition assay. Five commercial cockroach extracts were compared for Cr-PII levels by monoclonal antibody-base ELISA, and all extracts were found to contain detectable Cr-PII.

CONCLUSION

The 28-, 32-, and 45-kD components of Cr-PII may be considered as additional important allergens of American cockroach and monoclonal antibodies can be used to identify and define American cockroach allergens.

Pulmonary actinomycosis appearing as a "ball-in-hole" on chest radiography and bronchoscopy

A 40 year old diabetic man with pulmonary actinomycosis was admitted to hospital with recurrent haemoptysis. The chest radiograph showed an air meniscus in the left upper lobe, a rare presentation of pulmonary actinomycosis. Bronchoscopic examination revealed a mass in a cavity which has never been reported previously. He underwent lobectomy and the surgical specimen revealed sulphur granules, the typical pathological finding of actinomycosis, without evidence of fungal or mycobacterial infection.

Thoracoscopic-assisted lobectomy. Preliminary experience and results

A preliminary report is made on the use of videothoracoscopy to achieve pulmonary lobectomy in 16 patients, including 12 with centrally located pulmonary metastases and 4 with benign lesions (3 bronchiectases and 1 endobronchial hamartoma). Videothoracoscopy was performed on eight right-lower lobes, one middle lobe, two right-upper lobes, four left-lower lobes, and one left-upper lobe with a thoracoscope and conventional thoracic instruments. All patients received standard pulmonary lobe resection with lymph node clearance similar to that achieved with open thoracotomy. The mean operative time was 3 h (range, 2.5 to 4 h). Average blood loss was 100 mL and mean length of hospital stay was 6 days (range, 4 to 8 days). A combination of videothoracoscopy with use of conventional instruments resulted in similar performance but less chest wall interruption than in conventional pulmonary lobectomy. Videothoracoscopy showed safer and faster lung resection, which subsequently minimized the perioperative morbidity. Pain intensity was lessened, functional recovery was quicker, and hospital stays were shorter in the patients we reviewed.

Thoracoscopic surgery as a routine procedure for spontaneous pneumothorax. Results from 82 patients

A total of 82 consecutive patients with recurrent or persistent spontaneous pneumothorax were considered for thoracoscopic blebectomy or bullectomy and pleurodesis. The median age was 47 years, and 70% were men. All the patients were successfully treated using a video-assisted thoracoscopic technique. There were no deaths attributable to the procedure. Complications occurred in 6 patients (7.3%). Three patients (4%) with diffuse bullous lung disease had prolonged intubation (9, 11, and 12 days, respectively). Persistent air leaks lasting from 10 to 14 days occurred in 2 patients (3%). One patient had an endoloop slip from the lung parenchyma after a forceful sneeze 2 days after the operation. Air leak subsided after the second operation using a conventional suturing technique. Blebs or bullae were present in 69 patients (83%). These were ablated by endoscopic stapling (37 patients) and through thoracoscopic ligation using an endoloop technique (32 patients). In this group of patients, the median postoperative hospital stay was 5 days. Thirteen patients with air leaks and diffuse bullous lung disease received only talc insufflation thoracoscopically. All of them showed good lung expansion after the operation. There are no recurrences, with a mean follow-up of 22 months. These results suggest that thoracoscopic ablation of blebs or bullae and pleurodesis may be applicable to patients with spontaneous pneumothorax who require surgical intervention.

Application of thoracoscopy for lung metastases

Lung nodules in patients with a history of malignancy usually require tissue diagnosis that will provide prognostic information and dictate further therapy. Patients with a favorable tumor histologic condition and limited tumor burden were often considered for resection. This is usually accomplished by wedge resection through open thoracotomy when the lesions were peripheral. However, complications related to open thoracotomy often exclude poor-risk patients, especially those with impaired pulmonary function. Currently, technique of thoracoscopic resection is opening up new vistas and unimagined options for the thoracic surgeon in the management of pulmonary diseases. With the application of thoracoscopy and small incisions, it is now possible for the thoracic cavity and its contained organs to be thoroughly explored. Our recent experience with the thoracoscopic resection as a primary treatment for lung metastases is the focus of this report. Forty-seven patients with a history of malignancy and new lung metastases underwent this type of resection. Postoperatively, there is less pain, quick functional recovery, and excellent cosmetic healing. It is a safe and promising approach.

Enhancement of endothelium-dependent contraction of the canine coronary artery by UW solution

University of Wisconsin (UW) solution has been used almost routinely in the preservation of the hepatic, pancreatic, renal, and cardiac allografts. However, its effect on vascular endothelium is unknown. Experiments were designed to evaluate its effect on canine coronary endothelium. Canine coronary arteries (n = 8 in each group) were preserved in cold (4 degrees C) UW solution (group 1) and physiological solution (group 2) for 6 hr immediately after harvesting. Segments of preserved and control (group 3) coronary arteries with or without endothelium were then suspended in organ chambers to measure isometric force. Perfusate hypoxia (pO2 30 +/- 5 mmHg) caused endothelium-dependent contraction in the arteries of all 3 groups. However, vascular segments with endothelium of group 1 exhibited hypoxic contractions (107 +/- 26% of the initial tension contracted by prostaglandin F2 alpha 2 x 10(-6) mol/L, P < 0.05) that were significantly greater than those of the group 2 and group 3 segments with endothelium (25 +/- 5% and 20 +/- 4%). The hypoxic contraction in arteries of group 1 could be attenuated by NG-monomethyl-L-arginine (L-NMMA), the blocker of endothelial cell synthesis of the nitric oxide from L-arginine. The action of L-NMMA could be reversed by L-arginine but not D-arginine. Endothelium-dependent relaxation of coronary endothelium to acetylcholine and adenosine diphosphate and endothelium-independent relaxation and contraction of coronary smooth muscle were not altered by the UW solution. After preservation with the UW solution, endothelium-dependent contraction of the canine coronary arteries, occurs by L-arginine-dependent pathway, is enhanced. This augmentation by the UW solution would favor vasospasm after transplantation.

Thoracoscopic management of effusive pericardial disease: indications and technique

Video-assisted thoracoscopic technique was evaluated in 28 patients who underwent operation for massive pericardial effusion. Excellent results were obtained using this newly developed approach for inspection of all pericardial surfaces as well as pleural and pulmonary disorders. No perioperative or postoperative complications ensued. Videothoracoscopy revealed positive lung malignancies in 11 patients, and these would not have been promptly diagnosed without thoracoscopy. Thoracoscopy also confirmed metastatic deposits on the pleura and diaphragm in 4 other patients. The visible nodules were proved to be metastatic adenocarcinoma. In 13 patients, thoracoscopy did not reveal malignancy, although 2 of these patients had a clinically suspected malignant lung tumor. Other indications for thoracoscopic drainage included 2 patients with impending pericardial tamponade after heart procedures and 6 patients with recurrent/loculated pericardial effusion. All of the patients showed promising and favorable postoperative courses after thoracoscopy. From our experience, video-assisted thoracoscopy was a safe and effective procedure, especially for those patients with combined pericardial effusion and abnormal pulmonary or pleural pathology in whom subxiphoid pericardial window was not clearly diagnostic at the time of operation. It was effective also in the situation with recurrent or loculated pericardial effusion which allowed localization and drainage of it. We believe that the use of videothoracoscopy to visualize the whole pericardial and pleural cavity will continue to be of great benefit to patients with combined pericardial and pleural/lung diseases.

Imaged thoracic resection of a huge mediastinal tumor--role of extended incision and the use of conventional instruments

Intrathoracic lesions are usually removed through conventional thoracotomy. The long incision and the spreading of the rib usually results in much pain and interference of chest wall mechanics. Today, with the development of imaged thoracic surgery (combination of thoracoscope and video optics), major procedures can be performed through small incisions. However, indications are greatly limited due to lack of suitable instrumentation and restricted space of the trocar channel especially when a huge intrathoracic tumor is encountered. In this selected report, we demonstrate a successful procedure using extended incision and conventional instruments in imaged resection of a huge cystic intrathoracic tumor. The procedure offers the benefit of safe, easy and fast manipulation. The patient had an uneventful postoperative course and was discharged on the fourth postoperative day.

Protection of the brain by retrograde cerebral perfusion during circulatory arrest

Hypothermic circulatory arrest is commonly used to facilitate repair of complex congenital heart defects and aortic lesions and for complex neurosurgical procedures. However, extended periods of circulatory arrest may impair cerebral metabolism and cause ischemic injury. Retrograde cerebral perfusion has been applied recently in aortic surgery to protect the brain. From January 1991 to December 1993, 29 patients underwent emergency operations to repair acute type A aortic dissection with the aid of hypothermic circulatory arrest. Six patients received hypothermic circulatory arrest without retrograde cerebral perfusion with a rectal temperature of 16.4 degrees +/- 0.9 degrees C (mean +/- standard error of the mean, group 1). Retrograde cerebral perfusion during hypothermic circulatory arrest was performed in 15 patients with a rectal temperature of 15.9 degrees +/- 0.5 degrees C (group 2) and in eight patients with a rectal temperature of 21.7 degrees +/- 0.8 degrees C (group 3). The hypothermic circulatory arrest times were 25 +/- 4, 42 +/- 4, and 63 +/- 6 minutes, respectively (p < 0.05). The cardiopulmonary bypass times were 173 +/- 5, 184 +/- 7, and 143 +/- 6 minutes, respectively (p < 0.05). All patients survived the operation and regained consciousness with no neurologic defects. Follow-up (mean 23.2, 14.5, and 5.1 months, respectively) was complete in all patients except one. This patient, from group 2, was killed in a road traffic accident 12 months after the operation. Our experience suggests that retrograde cerebral perfusion can effectively protect the brain from ischemic injury and extend the safe period of hypothermic circulatory arrest. With the aid of retrograde cerebral perfusion, prolonged circulatory arrest can probably be performed safely with moderate hypothermia.

Video-assisted thoracic surgery. The Chang Gung experience

Thoracoscopy has assumed a major role in the management of a variety of surgical diseases of the chest. This technique, which was primarily devised for diagnostic purposes, has subsequently come to be used for therapeutic applications in most centers today. In this report we review 300 cases of therapeutic thoracic procedures in which a video-assisted technique was used. We describe mainly our own experience and the basic approach strategies we found helpful in the video-assisted procedures. No complications or deaths were attributable to these procedures. Our conclusions were as follows: (1) Video-assisted thoracic surgery can be as effective therapeutically as many formal thoracotomy. (2) Excellent exposure can be obtained by the use of double-lumen endotracheal tubes. (3) Video-assisted thoracic surgery is an excellent alternative treatment for pneumothorax, blebs, and bullous disease. (4) Video-assisted thoracic surgery allows safe, complete, visually guided wedge resection of lung lesions, lobectomy, pericardiectomy, removal of mediastinal tumor, esophagectomy, and reconstruction of the thoracic esophagus. (5) Video-assisted thoracic surgery also allows management of a broad scope of other general thoracic diseases such as empyema, pleural effusion, and chest trauma (hemothorax), as well as cancer staging. (6) Video-assisted thoracic surgery will not compromise the primary diagnostic and therapeutic goals set forth for the patient. (7) Because conventional instruments and extended manipulation incisions can be used, video-assisted thoracic surgery offers the promise of expediency, safety, minimal discomfort, less postoperative pain, quick functional recuperation, excellent cosmetic healing, shortened stays in the hospital, and therefore savings in cost. Accordingly, we are now using video-assisted thoracic surgery to treat the majority of patients with surgical diseases of the chest.

Ovarian hyperstimulation syndrome with minimal ascites and massive pleural effusion: report of a case

A 30-year-old woman was admitted to the hospital due to bilateral massive pleural effusion and right lung collapse with severe respiratory distress. She had been undergoing gamete intrafallopian transfer (GIFT) following three years of primary infertility. Ovarian stimulation was done with pure follicle stimulating hormone (FSH) and human menopausal gonadotropin (hMG) under pituitary suppression with leuprolide acetate. Bilateral chest pain and progressive dyspnea occurred six days after preovulatory oocytes with washed motile sperms were transferred laparoscopically to the fallopian tubes. Chest radiography, sonography and computed tomography revealed a massive right pleural effusion with right lung collapse, and a mild left pleural effusion. Abdominal sonography revealed minimal ascites. Supportive therapy including fluid supply and albumin infusion failed to improve the respiratory distress. A tube thoracostomy was performed, resulting in rapid reexpansion of the lung. The respiratory distress improved markedly after drainage of 6,800 mL of pleural effusion over 7 days. Massive serosanguineous pleural effusion with minimal ascites is unusual in ovarian hyperstimulation syndrome (OHSS). Tube thoracostomy is a safe and effective treatment for massive pleural effusion and lung collapse in the case of OHSS.

Acute endothelial reperfusion injury after coronary artery bypass grafting

Coronary artery endothelium exhibits functional impairment after ischemia and reperfusion. Canine left anterior descending coronary arteries were exposed to ischemia (60 minutes) followed by reperfusion (60 minutes) through a left internal mammary artery graft. In organ chamber experiments, control (left circumflex coronary artery) and reperfused (left anterior descending coronary artery) arterial segments were contracted with prostaglandin F2 alpha and exposed to hypoxia (oxygen tension = 35 +/- 5 mm Hg). Reperfused coronary rings with endothelium exhibited contractions to hypoxia that were significantly greater than contractions in control rings with endothelium (+78% +/- 8% and +14% +/- 5%, respectively; p < 0.05). This phenomenon could be blocked by NG-monomethyl-L-arginine. Electron microscopic studies showed platelet adhesion and aggregation, denudation of the endothelium and disruption of the intercellular junctions, edematous subendothelial matrix, and vesiculation of the smooth muscle cells in reperfused LAD. Swelling, vacuole formation, and loss of neurofilament occurred in the nerve fibers accompanying the vessels. These phenomena were not observed in control vessels. This study demonstrates that early after coronary artery bypass grafting, hypoxia can induce coronary vasospasm mediated by an L-arginine-dependent metabolic pathway in the endothelium. The ultrastructural changes in the coronary endothelium include platelet adhesion, aggregation, and platelet-induced contraction of coronary smooth muscle. The endothelium-dependent hypoxic coronary vasospasm and ultrastructural changes in the coronary endothelium may play an important role in the pathogenesis of myocardial ischemia and infarction after coronary artery bypass grafting.

Surgical treatment of acute type A aortic dissection with an intraluminal sutureless graft

The surgical treatment of acute type A aortic dissection remains a great challenge to all cardiac surgeons. From January 1991 to June 1993, 21 consecutive patients (13 men and eight women, aged 34 to 74 years) underwent emergency operations to repair acute type A aortic dissection, with the aid of hypothermic circulatory arrest. The intima tear was located in the ascending aorta in 13 patients, in the aortic arch in five patients, and in the descending aorta in three patients. The dissected ascending aorta was replaced with sutureless, intraluminal vascular grafts in all 21 patients. The intima tears in the aortic arch of five patients were primarily repaired. Modified Cabrol's shunts were created in seven patients for hemostasis, and Dacron grafts were used to wrap the ascending aorta in 18 patients. Retrograde cerebral perfusion during circulatory arrest was performed on 15 patients. The circulatory arrest time was 37 +/- 10 minutes (mean +/- SD). All patients survived the operation and regained consciousness in the early postoperative period without neurologic deficit. Post-treatment follow-ups (mean, 18.2 months) were completed in all patients except one, who died 12 months after the operation as a result of a traffic accident. All of the surviving patients are doing well without any further aortic operations. Our experience suggests that surgical repair of the acute type A aortic dissection can be a simple and safe procedure if sutureless intraluminal grafts are used and hypothermic circulatory arrest and retrograde cerebral perfusion are utilized.

Lymph node metastasis from carcinoma of the distal one-third of the stomach

BACKGROUND

A detailed and thorough pathoanatomic study of lymph node (LN) metastases of adenocarcinoma of the distal one-third of the stomach is lacking.

METHODS

From December 1987 to March 1992, 190 patients who underwent radical gastrectomy was analyzed. All LN were dissected and labeled according to the Japanese General Rules for the Gastric Cancer Study.

RESULTS

A total of 7052 LN with an average of 37.1 per specimen were removed. LN metastases were encountered in 121 patients (63.7%). The most frequent LN metastases were perigastric, above common hepatic artery, along left gastric artery, and hepatoduodenal ligament. The incidence of LN metastasis varied and was highest when tumor was located close to either curvature and extended to duodenum or midbody. The high incidence of LN metastases in the hepatoduodenal ligament was a unique pathologic feature of adenocarcinoma of the distal one-third of the stomach (P = 0.0012). Univariate and multivariate analysis revealed that depth of cancer invasion was the only factor related to LN metastases.

CONCLUSIONS

Cancer in the distal one-third of the stomach had a high incidence of LN metastasis to hepatoduodenal ligament nodes. The LN metastasis is correlated with depth of cancer invasion.