Lung ultrasound is non-inferior to bronchoscopy for confirmation of double-lumen endotracheal tube positioning: a randomized controlled noninferiority study

BACKGROUND

Appropriate placement of left-sided double-lumen endotracheal tubes (LDLTs) is paramount for optimal visualization of the operative field during thoracic surgeries that require single lung ventilation. Appropriate placement of LDLTs is therefore confirmed with fiberoptic bronchoscopy (FOB) rather than clinical assessment alone. Recent studies have demonstrated lung ultrasound (US) is superior to clinical assessment alone for confirming placement of LDLT, but no large trials have compared US to the gold standard of FOB. This noninferiority trial was devised to compare lung US with FOB for LDLT positioning and achievement of lung collapse for operative exposure.

METHODS

This randomized, controlled, double-blind, noninferiority trial was conducted at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand from October 2017 to July 2019. The study enrolled 200 ASA classification 1-3 patients that were scheduled for elective thoracic surgery requiring placement of LDLT. Study patients were randomized into either the FOB group or the lung US group after initial blind placement of LDLT. Five patients were excluded due to protocol deviation. In the FOB group (n = 98), fiberoptic bronchoscopy was used to confirm lung collapse due to proper positioning of the LDLT, and to adjust the tube if necessary. In the US group (n = 97), lung ultrasonography of four pre-specified zones (upper and lower posterior and mid-axillary) was used to assess lung collapse and guide adjustment of the tube if necessary. The primary outcome was presence of adequate lung collapse as determined by visual grading by the attending surgeon on scale from 1 to 4. Secondary outcomes included the time needed to adjust and confirm lung collapse, the time from finishing LDLT positioning to the grading of lung collapse, and intraoperative parameters such has hypotension or hypertension, hypoxia, and hypercarbia. The patient, attending anesthesiologist, and attending thoracic surgeon were all blinded to the intervention arm.

RESULTS

The primary outcome of lung collapse by visual grading was similar between the intervention and the control groups, with 89 patients (91.8%) in the US group compared to 83 patients (84.1%) in the FOB group (p = 0.18) experiencing adequate collapse. This met criteria for noninferiority per protocol analysis. The median time needed to confirm and adjust LDLT position in the US group was 3 min (IQR 2-5), which was significantly shorter than the median time needed to perform the task in the FOB group (6 min, IQR 4-10) (p = 0.002).

CONCLUSIONS

In selected patients undergoing thoracic surgery requiring LDLT, lung ultrasonography was noninferior to fiberoptic bronchoscopy in achieving adequate lung collapse and reaches the desired outcome in less time.

TRIAL REGISTRATION

This study was registered at clinicaltrials.gov, NCT03314519 , Principal investigator: Kasana Raksamani, Date of registration: 19/10/2017.

Long Term Outcomes and Durability of Bioprosthetic Valve for Valve Replacement at Siriraj Hospital

Objective: Bioprosthesis has been used in cardiac valve replacement for a long time. However, structural valve deterioration is still a major cause of failure. There are several risk factors for valve deterioration. This study evaluates the risk factors of valve deterioration in the long term (10 years) at Siriraj Hospital.Materials and Methods: We retrospectively reviewed the medical records of 249 patients who underwent mitral or aortic valve replacement between January 2006 and December 2012 using various tissue valves, comprising Carpentier–Edwards porcine, Carpentier–Edwards Perimount bovine pericardial, Carpentier–Edwards Perimount Magna bovine pericardial, and St Jude Trifecta bovine pericardial types. The information from each patient was entered into a database at the time of the operation and followed up regularly, with a mean follow-up of 10 years.Results: After 10 years follow-up time, the incidence of valve deterioration events were 1.2% and 8.43% in the first five and ten years, respectively. The overall death rate during follow-up was 2.41%. There were three statistically significant risk factors (p < 0.05) of valve deterioration: gender (female) (p = 0.042), age ≤ 60 years old (p = 0.010) and St Jude Trifecta bovine pericardial valve (p = 0.004).Conclusion: In the surgical populations who underwent valve replacement at Siriraj Hospital with tissue valves, we found an acceptable long-term durability of the tissue valve. The risk factors of valve deterioration were female gender, age ≤ 60 years old, and St Jude Trifecta bovine pericardial valve.

Survival of Non-Small Cell Lung Cancer Patients with Unexpected N2 after Complete Resection: Role of Aggressive Invasive Mediastinal Staging should be Considered

Objective: Mediastinal lymph node (N2) metastasis is one of the poor prognostic factors in non-small cell lung cancer patients (NSCLC). However, the accuracy of mediastinal lymph node staging in real practice is uncertain and inadequate. Consequently, the aim of this study was to determine the survival of NSCLC patients with clinically non-suspicious mediastinal lymph node metastases who underwent complete resection but were pathologically confirmed as having N2 metastases (unexpected N2).Materials and Methods: A retrospective review was performed of all pathology-proven N2 metastases NSCLC patients who underwent curative surgical resection from January 2007 to December 2016. A total of 158 patients were initially included in the study. After the exclusions (known N2, small cell carcinomas, neuroendocrine tumor), 125 unexpected N2 patients who underwent complete resection were analyzed. Survival analysis was determined using the Kaplan–Meier method and multivariate analysis was determined using the Cox regression method.Results: The overall 2-year, 3-year, and 5-year survival rates were 40%, 24%, and 20% respectively. Complete resection was achieved in all patients. Invasive mediastinal staging (IMS) was performed in 47 patients (37.6%), by endobronchial ultrasonography (EBUS) in 46 (36.8%) patients (82.6% negative and 17.4% inadequate tissue) while only 1 patient underwent mediastinoscopy. The factors affecting the survival rate upon comparison were the histology type (p=0.019), differentiate characteristics (p=0.004), adjuvant therapy (p=0.011), and presence of distant metastasis by postoperative re-staging (p=0.003). The independent predictive factors for survival werechemo-radiation therapy (odds ratio 0.367, 95% confidence interval 0.176–0.766) and distant metastasis (odds ratio 2.280, 95% confidence interval 1.334–3.897). However, a small size, periphery lesion, T staging, and number of N2 lesions were not significant factors.Conclusion: The survival rate of unexpected N2 patients was low despite complete resection being achieved in these patients. Adjuvant therapy seemed to improve survival for those with unexpected N2 metastasis as it is a systemic disease. However, not all patients received IMS, which was mostly done by EBUS and which had a high false negative, leading to underestimating the staging. Other modalities, such as cervical mediastinoscopy, videoassisted mediastinoscopic lymphadenectomy (VAMLA) or open biopsy should be considered for the adequate evaluation of N2 metastasis, nonetheless further study is still needed.

Low dose intraoperative ketamine infusion with multilevel paravertebral block for pain after video-assisted thoracic surgery: a randomized-controlled study

BACKGROUND

Intraoperative low-dose ketamine infusion has been reported to be an effective adjuvant to opioids for postoperative pain control without major side effects, but it has not been tested in video-assisted thoracic surgery (VATS). The aim of this study was to examine the effect of low-dose intraoperative intravenous ketamine infusion on 24-hour morphine requirement and acute postoperative pain following VATS for lung resection.

METHODS

This study was a single center, randomized, double-blind, placebo-controlled study. Thirty-two patients undergoing elective VATS for lung resection in a university hospital were included. Patients were randomly allocated (1:1 ratio) to receive either intraoperative low-dose ketamine (0.2 mg/kg/h) or normal saline infusion starting from intubation to the beginning of chest closure. All patients received multilevel thoracic paravertebral block (TPVB) and morphine was administered postoperatively via the patient-controlled analgesia pump using the same protocol. Time to first analgesia, postoperative cumulative morphine doses at 10, 30 minutes, and the consecutive 1, 2, 6, 12, 18, and 24 hours were recorded. Pain intensity during rest and deep breathing were also assessed by numeric rating scale (NRS) score at 1- and 24-hour postoperatively.

RESULTS

There was no significant difference in median (P25, P75) cumulative 24-hour morphine requirement between the ketamine and the control groups [15 (5.5, 29.5) vs. 22.5 (15.3, 40.8) mg, P=0.090]. Patients in ketamine group had significantly longer median pain free time than the control group (27 vs. 2 minutes, P=0.006). No difference in overall NRS score at rest or during deep breathing at 1- and 24-hour postoperatively was demonstrated (P=0.861).

CONCLUSIONS

Intraoperative low dose ketamine infusion in addition to TPVB does not reduce postoperative morphine consumption or pain intensity but may prolong pain free time in patients undergoing VATS for lung resection.

Comparison of High-Flow Humidified Oxygen With Conventional Continuous Positive Airway Pressure in Nonventilated Lungs During Thoracic Surgery: A Randomized Cross-Over Study

OBJECTIVE

This study assessed the efficacy of high-flow humidified oxygen (HFHO) as an alternative to continuous positive airway pressure (CPAP) for improving oxygenation while preserving nonventilated lung collapse during one-lung ventilation.

DESIGN

A prospective randomized cross-over trial.

SETTING

A tertiary medical center.

PARTICIPANTS

The study comprised 28 patients undergoing elective thoracotomy with one-lung ventilation using a double-lumen endobronchial tube placement.

INTERVENTIONS

The patients received prophylactic CPAP or HFHO to the nonventilated lung for 20 minutes and were then crossedover to the other oxygenation modality for 20 minutes, with a 20-minute recovery interval between the two modalities.

MEASUREMENTS AND MAIN RESULTS

Changes in respiratory parameters and lung deflation quality were recorded. Both CPAP and HFHO increased the partial pressure of arterial oxygen in either sequence in both groups, ranging from 31.8-to-66.0 mmHg. However, the increments from these two interventions were not statistically significant (95% confidence interval -12.84 to 21.87; p = 0.597). There were no differences in other parameters. Half the patients receiving CPAP experienced worsening of the surgical condition, whereas the HFHO patients experienced no change or reported a better lung deflation (p < 0.001).

CONCLUSION

HFHO could be an alternative method to CPAP for improving arterial oxygenation while preserving lung deflation during one-lung ventilation. However, additional studies are warranted in regard to its cost-effectiveness and establishment as a routine treatment.

Thoracic cancer surgery during the COVID-19 pandemic: a consensus statement from the Thoracic Domain of the Asian Society for Cardiovascular and Thoracic Surgery

OBJECTIVES

Healthcare resources have been mobilized to combat the COVID-19 pandemic of 2020. The Thoracic Domain of the Asian Society for Cardiovascular and Thoracic Surgery reports a consensus statement on the provision of thoracic cancer surgery during this pandemic.

METHODS

A Thoracic Experts Panel was convened by the Society. A consensus on the provision, safety, and setting of thoracic cancer surgery during the pandemic was obtained through a Delphi process.

RESULTS

Responses were received from 26 panel members (96% response rate) from 10 regions across Asia. The Society recommended that elective thoracic cancer surgery services may need to be reduced or postponed if medical resources were needed for COVID-19 patients, especially intensive care unit beds and ventilators. However, thoracic cancer surgery should proceed as normal for all solid tumors, without restrictions based on disease stage, availability of non-surgical treatment options, or patient condition (unless there is a high likelihood of postoperative intensive care unit stay). Aerosol-forming procedures should be avoided intra- and perioperatively. The surgical approach does not make a difference in terms of safety. Services for thoracic cancer patients should be offered only in hospitals that maintain isolation wards for patients with confirmed or suspected COVID-19.

CONCLUSIONS

Services for patients with thoracic cancer should be maintained during the COVID-19 pandemic. The position of the Society is that thoracic surgeons have a responsibility to perform good surgical management of thoracic cancer during the pandemic, to advocate for patients' rights to receive it, and to safeguard patients and staff from infection.

General thoracic surgery services across Asia during the 2020 COVID-19 pandemic

The COVID-19 pandemic of 2020 posed an historic challenge to healthcare systems around the world. Besides mounting a massive response to the viral outbreak, healthcare systems needed to consider provision of clinical services to other patients in need. Surgical services for patients with thoracic disease were maintained to different degrees across various regions of Asia, ranging from significant reductions to near-normal service. Key determinants of robust thoracic surgery service provision included: preexisting plans for an epidemic response, aggressive early action to "flatten the curve", ability to dedicate resources separately to COVID-19 and routine clinical services, prioritization of thoracic surgery, and the volume of COVID-19 cases in that region. The lessons learned can apply to other regions during this pandemic, and to the world, in preparation for the next one.

Surgical Outcomes of Adult Congenital Heart Disease with Left to Right Shunt at Siriraj Hospital

BACKGROUND

Outcomes of surgical treatment of adult congenital heart disease (ACHD) in developing country are scant but are of critical importance for caring of these patients.

OBJECTIVE

We studied characteristic and surgical repair outcomes of simple ACHD at Siriraj Hospital.

MATERIAL AND METHOD

We studied 297 adults with atrial septal defect (ASD), ventricular septal defect (VSD), or patent ductus arteriosus (PDA) whom underwent surgical repair between January 2006 and September 2014. There were 211 ASD, 80 VSD, and 6 PDA. We focused on perioperative data, follow-up data, and factor(s) associated with adverse events.

RESULTS

Of 297 patients, 37.4% were males; mean age was 41.8 years (range, 20-78 years). Pulmonary hypertension and valvular regurgitation (mitral, tricuspid, or aortic) were presented in 74.7% and 35.0% of the patients, respectively. Majority of defects were closed with patching (85.4% for ASD and 82.7% for VSD), while the rest were closed directly. Of the 190 concomitant procedures, most of them were tricuspid repair (28.9%), and mitral repair (17.4%). There were eight hospital deaths (2.7%). At median follow-up of 25 months (range, 1-102 months), the mean functional classification was reduced from 1.9 to 1.1 (p<0.01). There were five re-interventions and four late deaths. Overall survival was 96.1% at five years and 76.1% at eight years. Concomitant procedure(s), tricuspid, and mitral regurgitation were associated with worse survival. Concomitant procedure(s), mitral, and aortic regurgitation were associated with re-intervention.

CONCLUSION

Outcomes of surgical repair of simple ACHD were good. Valvular regurgitation and concomitant procedure(s) adversely affected the outcomes.

Pathological confirmed diagnosis of asbestosis: the first case report in Thailand

Asbestosis is an occupational lung disease defined as pulmonary fibrosis caused by asbestos. Asbestosis was previously reported in Thailand based on radiologic findings, which demonstrated interstitial lung with calcified pleural plaques, and the patient worked in a fiber cement factory. However there was some doubt about the diagnosis because clinical and radiological findings are nonspecific; there was no data support of asbestos exposure in the patient and no histologic confirmed diagnosis. Histologic diagnosis is most useful when an equivocal of ahistory of asbestos exposure in patients with interstitial lung diseases take place. The authors report a patient presenting with progressive dyspnea for 2 years. She worked in an electric, wire, mesh fan cover factory to check quality of protective wire mesh for 10 years until the factory was closed 6 years ago. This type of factory had never officially reported asbestos use. Her clinical manifestations and radiologic findings are compatible with interstitial lung disease. She subsequently underwent thoracotomy with wedge lung resection. Pathology revealed interstitial fibrosis with honeycombing. Asbestos bodies were found more than 10 per cm2 in the fibrosis. She was diagnosed asbestosis. The patient is suffering from dyspnea, severe hypoxemia and cor pulmonale. The patient is put on waiting lists for heart lung transplantation. The authors thus confirmed that asbestosis exists in Thailand. A policy to protect workers and people who may have risk of asbestos exposure is necessary, since diseases related to asbestos are incurable, but preventable.

Validation of EuroSCORE for coronary artery bypass grafting at Siriraj Hospital

OBJECTIVE

To access the performance of the EuroSCORE when applied to CABG patients at Siriraj hospital.

MATERIAL AND METHOD

One thousand five hundred forty nine patients diagnosed with coronary artery disease (CAD) who underwent isolated CABG between January 2007 and December 2009 was prospectively studied.

RESULTS

The patients included 1,102 men and 447 women and had a mean age of 67 years old. The mean additive score in expired and survived groups were 9.65 +/- 5.14 and 3.87 +/- 3.06. In logistic, score were 25.43 +/- 26.31 and 4.88 +/- 7.88 respectively (p < 0.001). The best cut-off value of EuroSCORE for prediction of a death rate was 6 for additive score and 10 for logistic score. Area under the curve was 0.831 for the additive score and 0.823 for the logistic score. The observed overall mortality rate was 2.0% while the predict mortality was 5.27%. The difference between observed and predicted deaths was significant with additive score and logistic score (p < 0.001).

CONCLUSION

Our results suggest that EuroSCORE is not valid for CABG in Thai patient due to over prediction.

Surveillance of pediatric cardiac surgical outcome using risk stratifications at a tertiary care center in Thailand

Objectives. To determine in-hospital mortality and complications of cardiac surgery in pediatric patients and identify predictors of hospital mortality. Methods. Records of pediatric patients who had undergone cardiac surgery in 2005 were reviewed retrospectively. The risk adjustment for congenital heart surgery (RACHS-1) method, the Aristotle basic complexity score (ABC score), and the Society of Thoracic Surgeons and the European Association for Cardiothoracic Surgery Mortality score (STS-EACTS score) were used as measures. Potential predictors were analyzed by risk analysis. Results. 230 pediatric patients had undergone congenital cardiac surgery. Overall, the mortality discharge was 6.1%. From the ROC curve of the RACHS-1, the ABC level, and the STS-EACTS categories, the validities were determined to be 0.78, 0.74, and 0.67, respectively. Mortality risks were found at the high complexity levels of the three tools, bypass time >85 min, and cross clamp time >60 min. Common morbidities were postoperative pyrexia, bleeding, and pleural effusion. Conclusions. Overall mortality and morbidities were 6.1%. The RACHS-1 method, ABC score, and STS-EACTS score were helpful for risk stratification.

Surgical pathology and etiology of 278 surgically removed mitral valves with pure regurgitation in Thailand

INTRODUCTION

There are multiple causes of mitral regurgitation. Its etiology includes floppy valve, postinflammatory disease, infective endocarditis, and other disorders. Recently, there has been an increased tendency to remove only portions of the mitral valve, causing difficulty in the determination of etiology. Our objective was to study the pathology and etiology of mitral regurgitation from surgically removed specimens.

METHODS

Native mitral valve specimens surgically excised due to mitral insufficiency were examined. Etiology was determined according to macroscopic, microscopic, clinical, and operative findings.

RESULTS

Among 278 mitral valve specimens, 43% were classified as floppy valve, 31% as postinflammatory disease (presumably associated with rheumatic fever), 12% as infective endocarditis, and 14% as miscellaneous group. In floppy valves, diffuse myxoid change and chordal rupture were the main findings. In postinflammatory disease, moderate neovascularization and chronic inflammatory cell infiltration were most commonly found. Aschoff bodies were found in two cases. In infective endocarditis, gram-positive cocci were found in 70% of cases. In the miscellaneous group, three cases were related to Marfan syndrome and one case was related to papillary muscle necrosis. In comparison with postinflammatory disease, the posterior leaflet in the floppy valve had a significantly longer basal free-edge length, a more frequent chordal rupture, and an higher mean age of patients. Among completely and partially excised specimens with postinflammatory disease, there were no significant differences in microscopic findings.

CONCLUSION

The three most common etiologies in mitral regurgitation were floppy valve, postinflammatory disease, and infective endocarditis. Macroscopic, microscopic, clinical, and operative findings are important in the evaluation of etiology, especially in partially excised specimens.

Ruptured right aortic arch aneurysm

A case of a ruptured right aortic arch aneurysm in a 74-year-old woman presenting with shock is reported. The diagnostic and operative findings are presented. We discuss the surgical approach and review the literature.

HLA class I serotypes and cytotoxic T-lymphocyte responses among human immunodeficiency virus-1-uninfected Thai volunteers immunized with ALVAC-HIV in combination with monomeric gp120 or oligomeric gp160 protein boosting

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.

Pathology and etiology of 110 consecutively removed aortic valves

OBJECTIVES

To study the pathology and determine the etiology and prevalence of aortic valve disease from surgically removed aortic valve specimens.

MATERIAL AND METHOD

All the native surgically excised aortic valves (AV) received from June 1997 to March 1999 (22 months) were studied macroscopically including cuspal measurements and microscopically. By preoperative echocardiographic and macroscopic studies, they were classified into functional disorders of predominant aortic stenosis (AS), aortic stenosis with regurgitation (AS-AR) and predominant aortic regurgitation (AR). The patients' medical records were reviewed and the clinical information was extracted. The etiology was determined according to the macroscopic, microscopic and clinical findings.

RESULTS

Among 110 AV (76 isolated AV and 34 with concomitant mitral valves from patients aged 15-96 years, mean age 47.54 years; male:female = 1.39:1) there were 25 AS (22.73%), 34 AS-AR (30.91%) and 51 AR (46.36%) cases. Eighty-four (76.36%) were tricuspid, 16 (14.54%) were bicuspid and 10 were undetermined. Cuspal measurements of each disease were provided and compared. All AS specimens were related to moderate to severe calcification and causes included postinflammatory disease (14 cases, 56%; age range 38-67 years, mean age 53.29 years, male:female = 0.56:1), degenerative calcific change (11 cases, 44%, age range 56-76 years, male:female = 1.2:1; mean age 69 years of 5 tricuspid AV and 60.83 years of 6 bicuspid AV). In AS-AR, 29 cases (85.29%; mean age 47.10 years; male:female = 1.23:1) were attributable to postinflammatory disease and 5 cases (mean age 70.20 years; male:female = 1.5:1) to degenerative calcific change. In pure AR, there were 21 cases (age range 15-65 years, mean age 29.76 years) of postinflammatory disease, 14 cases of infective endocarditis (IE) and postIE (age range 20-63 years, mean age 42.21 years; all 10 IE cases contained gram positive cocci), 1 case (age 55 years) of bicuspid calcific change, 8 cases of AV with dilated valve ring, 5 cases of miscellaneous causes and 2 cases of indeterminate etiology. Aschoff bodies were found in 3 AR cases. Four of 18 postinflammatory AS-AR and 4 of 14 postinflammatory disease AR cases had past history of rheumatic fever. One postinflammatory AS also had infective endocarditis from gram positive cocci without clinical sign. Severe degenerative calcific change had a higher incidence of underlying diabetes (3 of 15 cases, 20%), hypertension (8 of 14 cases, 57.14%) and dyslipoproteinemia (9 of 13 cases, 69.23%) in comparison with 3.37% (3/89) for diabetes, 9.09% (8/88) for hypertension and 30.99% (22/71) for dyslipoproteinemia in other AV diseases in combination.

CONCLUSION

The three common causes of severe AV functional disorders were postinflammatory disease (58.18%), degenerative calcific change (15.45%) and IE-postIE (12.72%). Underlying diseases of severe degenerative calcific change included hypertension, dyslipoproteinemia and diabetes. Macroscopic and microscopic examinations together with clinical information, echocardiographic findings and operative details are important in evaluating the etiology of valvular diseases especially in severely calcified specimens.

Cytotoxic T lymphocyte responses to vaccinia virus antigens but not HIV-1 subtype E envelope protein seen in HIV-1 seronegative Thais

The HIV-1 prime boost phase I/II vaccine trial using a recombinant canarypox vector, vCP1521, containing subtype E env (gp120), and subtype B env (gp41), gag and protease has started in Thailand. We have demonstrated that although 4 from 15 human immunodeficiency virus type 1 (HIV-1) seronegative Individuals showed cytotoxic T lymphocyte (CTL) responses to vaccinia virus antigens, none of them showed specific CTL responses to subtype E Env after in vitro stimulation. This preliminary study suggests that specific CTL responses to subtype E envelope detected in HIV-1 seronegative Individuals after vaccination should be considered as specific responses to the immunization.

Double annulus enlargement, Rastan-Manouguian's technique: a case report

A 35-year old female patient underwent a double valve replacement. The operative findings revealed a small aortic annulus (about 17 mm in diameter). In order to implant the adequate-size prosthetic valve, the aortic and mitral annulus were enlarged using the technique described by Rastan and Manouguian. The annulus were enlarged with a patch of gel-sealed dacron graft. After the enlargement, the prosthetic valve No. 23A and 31M could be implanted in the aortic and mitral annulus, respectively. This is an effective technique to enlarge the aortic and mitral annulus in a double valve replacement procedure. The annular diameter could be increased approximately 30 per cent.

Left ventricular outflow tract obstruction due to a left ventricular myxoma: a case report and review of the literature

A 17-year-old-man who presented with syncope, had a left ventricular (LV) myxoma causing left ventricular outflow tract obstruction. The tumor was removed through left ventriculotomy using conventional cardiopulmonary bypass with good result. There have been 47 cases of LV myxoma reported in the world literature since 1957. Most of them are symptomatic (92.7%). Systemic embolism is the most common manifestation (50%) and often leads to death. The surgical removal should be performed urgently. Resection of the mass with limited normal tissue surrounding its pedicle is recommended. There are only three recurrences and five operative deaths.

Progress and achievement of rabies control in Thailand

The breakthrough in production of highly efficacious human and animal rabies vaccines has led to successful rabies control in developed countries, but rabies is still a major health problem in many developing countries. In Thailand, the new cell culture vaccines-purified chick embryo cell (PCEC), purified Vero cell (PVRV), purified duck embryo (PDEV) and human diploid cell (HDCV) are available, and since 1993 have completely replaced the nervous tissue vaccines. The impact of these cell culture vaccines has been considerable, with the number of human rabies deaths decreasing from 200-300 in the early 1980s to 74 in 1995. Rabies prevention has also focused on the vaccination of dogs, and since 1992, the year the Rabies Prevention Act was announced, every owned dog has to be vaccinated at 2-4 months of age annually thereafter. However, only about 20% of dogs have been vaccinated. In 1995, the Ministry of Agriculture and Cooperation collaborated with the Ministry of Public Health to set up a target of no human rabies deaths in 1996, and a rabies-free Thailand by the year 2000. An extensive educational campaign is underway.

HIV-1 variants in South and South-East Asia

HIV spread in South and South-East Asia is most alarming, and genetic variability of HIV-1 is an important consideration in vaccine development. In this study, we examined the third variable (V3) region of env gene of HIV-1 variants prevalent in Thailand, Malaysia, India, and the Philippines. By phylogenetic tree analyses, an HIV-1 variant from an injecting drug user (IDU) in Thailand belonged to subtype B, and HIV-1 variants from 2 IDUs in Malaysia were classified into 2 subtypes, B and E. One HIV-1 variant from a male homosexual in the Philippines belonged to subtype B. Out of 8 HIV-1 variants from sexually transmitted disease patients in India, 7 belonged to subtype C, and one to subtype A. Although the total number of individuals examined in this study was limited, 4 HIV-1 subtypes were found in South and South-East Asia and large international movements of HIV-1-infected individuals in this region could induce global dissemination of these HIV-1 variants.

Incidence of Mycoplasma pneumoniae, Chlamydia trachomatis, and viral infections in pneumonia cases under six months of age, Bangkok, Thailand

The incidence of infections by Mycoplasma pneumoniae, Chlamydia trachomatis and respiratory viruses was investigated in 76 pneumonic patients aged under 6 months who attended Ramathibodi and Siriraj Hospitals in Bangkok during two study periods. M. pneumoniae infection was not found in any case from either hospital by serological diagnosis. By the isolation method, C. trachomatis infection was found in 7(16.7%) of 42 patients from Ramathibodi Hospital and 5(21.7%) of 23 patients from Siriraj Hospital with the average male:female ratio of 2.6:1; and 91.7% of the infected cases were under 3 months old. Laboratory diagnosis of respiratory virus infection was performed by indirect immunofluorescence (IIF), isolation, and by antibody detection. Data from Ramathibodi Hospital showed that 11 (24.4%), 4 (8.9%), 3 (6.7%) of the 45 patients were infected by respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus type 3, and some other viruses, respectively; infection rates of 10 (32.3%), 4 (12.9%), 1 (3.2%) and 1 (3.2%) by those viruses respectively, were observed in the 31 patients from Siriraj Hospital.

Detection of human cytomegalovirus in urine of infants by polymerase chain reaction

Polymerase chain reaction (PCR), viral isolation and serological methods were used to diagnose HCMV infection in infants. Specimens of urine and clotted blood were collected from suspected cases of congenital or HCMV infection who attended the Pediatric Clinic, Siriraj Hospital. Prevalence of HCMV infection was found in 3 per cent of infants aged under 14 days and increased to 48 per cent in infants aged over 14 days. PCR was the most sensitive technique, it could detect HCMV infection in 29 per cent of the study infants, whereas, detection rate by isolation was 17 per cent and by specific IgM ELISA was 15 per cent. Sensitivity and specificity of PCR compared with isolation and/or serology were 93 per cent and 96 per cent, respectively. Detection of HCMV in urine by PCR can be used as a sensitive and rapid test for diagnosis of HCMV infection in infants.

The abbreviated 2-1-1 schedule of purified chick embryo cell rabies vaccination for rabies postexposure treatment

During August 1988 to January 1990, the immunogenicity and safety of purified chick embryo cell rabies vaccine (PCEC) given by the conventional and abbreviated regimens in 82 vaccinees moderately to severely exposed to laboratory proven rabid animals were studied. The 16 vaccinees received PCEC six doses as conventional schedule on days 0, 3, 7, 14, 28 and 90, the 11 vaccinees received six doses of PCEC plus human rabies immune globulin (HRIG) on day 0. The 29 vaccinees received an abbreviated schedule of PCEC as two doses on day 0, one dose each on days 7 and 21 and the 26 cases received PCEC abbreviated schedule plus HRIG on day 0. The kinetics of the neutralizing antibodies on days 0, 7, 14, 28, 56, 180 and 365 were studied for comparative purpose. All vaccinees had high antibody levels from day 14 which last longer than a year and were safe after one year follow up. The adverse reactions of the vaccine were mild and self-limited.

Prevalence of human herpesvirus 6 in Thai people and its correlation with human immunodeficiency virus type 1 infection

Human herpesvirus 6 (HHV-6) is a human herpesvirus isolated from patients with various lymphoproliferative disorders and acquired immunodeficiency syndrome (AIDS). The prevalence of HHV-6 infection and its correlation as a cofactor in pathogenicity of HIV infection was investigated in serum samples from 365 healthy volunteers at various age groups, 50 persons at risk for HIV-1 infection, and 90 HIV-1 seropositive individuals. Sera were screened and titrated for antibodies against HHV-6 by a standard indirect immunofluorescence assay on an acetone fixed HHV-6 infected HSB2 cells. The data show high prevalence of HHV-6 in Thailand (71.7%) and the infection is acquired early in life. Prevalence of anti-HHV-6 IgG antibodies was not strikingly different among people at risk for HIV infection, asymptomatic HIV-1 infected cases, and aged-matched controls with low risk for HIV-1 infection. The AIDS cases showed high titers of anti-HHV-6 IgG antibody and high rates for presence of anti-HHV-6 IgM antibody (33.3%) which suggests higher prevalence of HHV-6 infection by either reactivation of an earlier HHV-6 infection or a new primary infection.

Detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA in breast milk and colostrum of seropositive mothers

There is increasing evidence of vertical transmission of HIV-1 to infants through breast feeding of milk from HIV-1 infected mothers. It has been postulated that transmission occurs mainly via ingestion of infected cells in breast milk and colostrum. In this study, detection of HIV-1 proviral DNA was used to prove that cells from colostrum and milk do contain HIV. DNA were extracted from these cells of colostrum and milk of 18 seropositive mothers and amplified by nested PCR for HIV-1 gag and pol and 44 per cent were positive mostly by two primers. All ten negative control samples from seronegative mothers were negative. This study demonstrated the infectivity of breast milk and colostrum. Nevertheless, recommendation against breast-feeding should be weighed against poor alternatives in low socioeconomic families.

Immunoglobulin G antibody capture enzyme-linked immunosorbent assay: a versatile assay for detection of anti-human immunodeficiency virus type 1 and 2 antibodies in body fluids

In tests on specimens of dried blood, saliva, and urine from 55 human immunodeficiency virus (HIV)-seropositive and 55 HIV-seronegative patients, an immunoglobulin G capture enzyme immunoassay for the detection of antibodies to HIV types 1 and 2, GACELISA, gave 109 of 110, 109 of 109, and 109 of 110 correct results, respectively. This performance, achieved in a laboratory previously unfamiliar with the assay, suggests that GACELISA is a useful new epidemiological tool for the study of HIV infection, equally applicable to all three kinds of specimen.

Epstein-Barr virus serological markers for nasopharyngeal carcinoma in Thailand

The present study reports on the prevalence of specific IgA and IgG antibodies to EBV viral capsid antigen in nasopharyngeal carcinoma (NPC) patients with different histological types of carcinoma and their age-matched controls by the indirect immunofluorescence test, using the B-95-8 lymphoblastoid cell line as source of viral capsid antigen. EBV specific IgG was found in almost all the study cases, and antibody titers were significantly higher in the NPC patients than in non-cancer controls. GMT of anti-EBV IgG in NPC patients, patients with other malignant diseases, and those with non-malignant diseases were 371.5, 97.7 and 35.5, respectively. Anti-EBV specific IgA was more specific to NPC than was IgG, and was present in 86.5% (83 of 96) cases of NPC patients, 6.6% (2 of 30) of patients with other cancers, and 3.1% (3 of 97) cases of non-malignant diseases. A weak correlation between level of anti-EBV IgA in NPC patients was observed (r = 0.3). EBV IgA was found in all histological types of NPC, ie, WHO types 1, 2 and 3, but WHO type 1 was rare among NPC patients in Thailand. Use of anti-EBV IgA for monitoring cancer therapy is to be further investigated.

A hospital-based study of acute viral infections of the respiratory tract in Thai children, with emphasis on laboratory diagnosis

The hospital-based study described here examined the viruses found in 738 children less than 5 years old who presented at Ramathibodi Hospital, Bangkok, Thailand, from January 1986 to December 1987 with acute respiratory tract infections. Three methods for detection of viral infection are compared: direct examination of epithelial cells of the respiratory tract with the use of fluorescent antibody staining, isolation of virus, and measurement of antibody in acute- and convalescent-phase sera. Viral infections were found in 44.7% of the study population. Diagnosis by the examination of epithelial cells with the fluorescent antibody staining procedure was found to have several deficiencies; however, this technique was the most sensitive for diagnosis of infection due to respiratory syncytial virus. Isolation of virus was the best method for identification of adenoviruses, parainfluenza 1 and 3 viruses, and influenza B virus. Problems associated with serodiagnosis included failure to obtain specimens of convalescent-phase blood in 24.5% of cases and insensitivity of serodiagnosis for young children except for the identification of antibody to influenza A virus. The combination of all three tests yielded the best rate of detection of virus.

Rabies and post-exposure prophylaxis in Thai children

Thailand is an endemic area for rabies, with approximately 300 human deaths reported annually. More than half of the rabies patients are children under 14 years of age. This paper reports clinical data of paediatric rabies cases occurring from 1980 to 1986, and the protective efficacies of human diploid cell rabies vaccine (HDCV) and purified Vero cell rabies vaccine (PVRV) in children exposed to rabid animals. The analysis of 120 medical records revealed that rabies in children had incubation periods which ranged from less than fifteen days to more than three months, but generally between one to three months. The most frequent symptoms observed in the patients were hydrophobia, restlessness, fever, vomiting and aerophobia. Most of the rabid children admitted to hospital died within 24 hours. HDCV was administered to 50 children exposed to rabies with the cumulative dosages of 327 ml. All patients survived without serious adverse effects during a-two year follow-up. Mild reactions were seen in 1.5 percent (5/327 doses). Unfortunately, levels of rabies antibody in these vaccinees were not determined. Among another series of children exposed to rabid animals, comprising 27 individuals who received a total of 168 doses of PVRV, only mild local reactions were seen in 6 subjects. No rabies deaths were reported in 2 years of follow-up. The children who received PVRV either with or without human rabies immune globulin developed similar levels of rabies neutralizing (NT) antibody, which reached the high titers on day 30. At one year after the first dose of vaccination, all vaccinees still had NT antibody at titers higher than 0.5 IU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

High prevalence of delta virus infection in Thai intravenous drug abusers

The prevalence of antibodies to delta virus (anti-delta) in the selected groups of hepatitis B surface antigenemia population was investigated. The subjects were 84 intravenous drug abusers; 20 chronic hepatitis, 12 cirrhosis, 6 primary hepatocellular carcinoma and 46 asymptomatic healthy carriers. Anti-delta was detected in 65.48% of intravenous drug abusers, 11.11% of chronic active hepatitis and 8.33% of cirrhosis cases. None of asymptomatic carriers had anti-delta. In addition, 51 acute icteric hepatitis B patients who were positive for HBs Ag and 20 IV drug abusers positive for anti-HBc only (HBsAg and anti-HBs negative) were negative for anti-delta.

Prevalence of cytomegalovirus antibodies in Thai blood donors

Antibodies to cytomegalovirus (CMV) were determined in Thai blood donors using the complement fixation (CF) test and enzyme-linked immunosorbent assay (ELISA). A total of 203 voluntary blood donors, 181 males and 22 females, who came to the Blood Bank at Siriraj Hospital during February 1985, were investigated. Their ages ranged from 17 to 53 years (mean 24.3 +/- 6.9). Seventy-three out of 156 (46.8%) and 171 out of 203 (84.2%) sera were positive for CMV antibodies as detected by the CF test and ELISA respectively. The result of ELISA showed that 95.5 per cent of the female blood donors and 82.9 per cent of the males possessed CMV antibodies. No difference in the geometric mean titres of either sex was noted. The findings indicated that ELISA was more sensitive than the CF test for detecting CMV antibodies. The high percentage of CMV-seropositive blood donors indicates that CMV infection is common in this country. Therefore, it might be necessary to test blood donors for CMV antibodies when they are giving blood for use by certain patients, especially immunocompromised ones; the same observation applies with regard to organ donors before transplantation is carried out.

Susceptibility to varicella-zoster virus in Thai children and young adults

During 1982-1983, susceptibility to varicella-zoster virus (VZV) in 224 Thai subjects at high risk for varicella infection was studied. The immune adherence hemagglutination (IAHA) and VZ skin test were carried out to determine VZV immunity in immunocompromised children and young adults. The history of varicella and herpes zoster from each subject was recorded. The mean +/- SD age in children and young adults were 7.3 +/- 2.8 and 19.6 +/- 1.2. Negative IAHA test was found in 74.2% of 62 children and 35.2% of 162 young adults. The increase in immune individuals was demonstrated with advancing age. Response to VZ skin test showed positive results in 79 of 162 (48.8%) young adults. The seronegativity was related to the negative VZ skin test (p less than 0.001, X2 test). Regardless of antibody detection or VZ skin test, 47 of 162 (29%) young adults were susceptible. According to the positive history of varicella and of herpes zoster obtained from 95 young adults, 80% had developed varicella during 1 to 10 years of age and 8.8% had positive history of herpes zoster. The findings suggest that the IAHA and VZ skin test should be used together for assessing VZ immunity. Varicella vaccination is highly recommended for susceptible persons who may develop severe illness.

Rubella outbreak in Thailand 1983-1984: a study at Siriraj Hospital

The recent rubella epidemic in Thailand prevailed from September 1983 to August 1984 with its peak in March. Throughout the outbreak, approximately 70% of the cases diagnosed clinical rubella were laboratory proved. In the middle of the outbreak, accuracy of the clinical diagnosis was 75-87%, while it was 25-33% at the beginning and the end. Concerning the clinical findings in rubella, maculopapular rash may be generalized or localized, and lymphadenopathy occurred only in 40% of the clinical cases. Lymphadenopathy and respiratory symptoms appeared 3 times more frequent than those in the non-rubella cases. Rubella inapparent infection occurred in 5.14% of the contact cases. Acquisition of the disease after contact did not depend on the degree of close relationship between the index cases and the contact cases. Outcome of pregnancy and congenital rubella infection after the outbreak have to be further investigated.

Purified chick embryo cell (PCEC) rabies vaccine for human use: clinical trials

The purpose of the study was the clinical evaluation of the new PCEC-Rabies-Vaccine. In 620 healthy volunteers mild local side-reactions could be observed in less than 2% of the vaccinations. No relevant general reactions have been reported or seen after the 2200 injections apart three cases of urticaria. All the 218 volunteers tested developed neutralising rabies antibodies of the IgG-type between day 0 and day 30 after the first vaccination dose. In 45 patients the PCEC-Rabies-Vaccine, applied together with human rabies immunoglobulin in a postexposure vaccination, afforded protection against rabies after contact with a proven rabid animal. The clinical trials are proof that the compatibility and efficacy of the PCEC-Rabies-Vaccine match the high standards established by the HDC-Rabies-Vaccine.

Detection of varicella-zoster antibody by immune adherence hemagglutination test

The immune adherence hemagglutination (IAHA) is a more sensitive and specific test for evaluation of humoral immunity to varicella-zoster virus (VZV) than a conventional complement fixation (CF) test. The equipment, reagents, procedure used in the IAHA are basically the same as those employed in the CF test. After VZ vaccination, seroconversions detected by IAHA test were significantly greater than those by CF test (P less than 0.01, chi 2 test). Moreover, the IAHA titers were higher about 4 times (G.M. 30.9 vs 8.2) and persisted longer than CF titers. Although the IAHA antigen is not a commercial product, the IAHA is sensitive and suitable assay for VZ antibody determination in routine serological laboratory.