Saravana Babu

Thermal, structural and spectroscopic properties of Pr3+-doped lead zinc borate glasses modified by alkali metal ions

Abstract This paper offers a study on Pr3+-doped alkali and mixed-alkali borate glasses prepared by the melt quenching technique and characterized by thermal, structural and spectroscopic studies. The amorphous nature of the glassy systems was identified based on X-ray diffraction. The thermal behaviour of glasses was studied using differential thermal analysis (DTA). The functional groups contained in the glasses were identified by Fourier transform infrared spectroscopy (FTIR). Spectral intensities were evaluated from the absorption spectra and used for calculating J–O intensity parameters, Ωλ (λ = 2, 4 and 6). Further, these parameters were used for calculating different radiative properties. The best radiative state was identified as the laser transition state among the various states. Emission analysis was performed for this state by calculating the branching ratios and stimulated emission cross sections (σp) for all the prepared glasses. These studies suggest that borate glasses are useful for visible fluorescence.

Intraoperative Transesophageal and Postoperative Transthoracic Echocardiographic Evaluation of a Mechanical Heart Valve Prosthesis Implanted at Aortic Position

OBJECTIVE The aims of this study were to evaluate the intraoperative transesophageal echocardiographic (iTEE) characteristics and Doppler flow profile of aortic Chitra heart valve prosthesis (CHVP) under stable hemodynamic and loading conditions, and to compare and correlate the iTEE data with the postoperative transthoracic echocardiography (TTE) data obtained at 48 hours (TTE1) and 3 months (TTE2) after the surgery. DESIGN Prospective, observational study. SETTING University-level tertiary referral hospital. PARTICIPANTS Forty patients between 18 years and 65 years of age undergoing elective aortic valve replacement (AVR) using CHVP during the period January 2015 to August 2016. INTERVENTIONS After obtaining permission from institutional ethics committee, 40 patients undergoing elective AVR were studied prospectively. The iTEE examination was performed in the pre-cardiopulmonary bypass (CPB) and post-CPB period in all the study subjects. CHVP was subjected to iTEE two-dimensional (2D) echo, color Doppler, and spectral Doppler evaluation under stable hemodynamic and loading condition in the post-CPB period after the administration of protamine. The CHVP were re-evaluated using TTE in all the patients 48 hours after the surgery (TTE1) and 3 months after the surgery (TTE2). The iTEE and postoperative TTE Doppler values were compared and correlated. MEASUREMENTS AND MAIN RESULTS The CHVP could be imaged adequately and interrogated with Doppler in all the patients. None of the patients had restriction of occluder mobility or unstable seating of the valve. The intraoperative flow dependent (peak velocity [PV] and mean pressure gradient [MPG]) and less flow dependent (Doppler velocity index, acceleration time, acceleration time/ejection time, effective orifice area [EOA] and indexed EOA) Doppler parameters of CHVP were measured as per the American Society of Echocardiography recommendations. The PV and MPG of CHVP measured by iTEE showed no statistical difference (p > 0.05) and were in limits of agreement when compared with TTE1 and TTE2 data. CONCLUSION The iTEE features of CHVP were found compliant with the criteria set by the ASE defining normal functioning of an aortic valve prosthesis. The iTEE Doppler parameters obtained under stable loading conditions strongly predicted the postoperative values of Doppler parameters on TTE examination. The iTEE Doppler values can be used as the reference values for the postoperative follow up studies.

Three-dimensional parametric imaging for intraoperative quantification of regional left ventricular function in ischemic cardiomyopathy

© 2017 Annals of Cardiac Anaesthesia | Published by Wolters Kluwer Medknow The Editor, The intraoperative assessment of regional left ventricular (LV) function using three‐dimensional (3D) echocardiographic parametric imaging is evolving as the technique has a steep learning curve. The two‐dimensional wall motion score index is a subjective and a semi‐quantitative way of describing segmental contractile dysfunction. Parametric imaging provides a finer approach; it processes more than 800 endocardial data points to develop bull’s eye diagrams of 17‐segmented LV model as described by the American Society of Echocardiography in transthoracic echocardiographic orientation.[1]

Distortion of aortic valve from mechanical traction imposed by the mitral valve prosthesis: The three-dimensional transesophageal echocardiographic perception

Iatrogenic injury to the aortic valve is a rare but frequently reported complication during mitral valve surgeries. Intraoperative 2-dimensional transesophageal echocardiography (2D TEE) has a major impact in diagnosing these injuries, so that timely intervention is possible. However, 2D TEE has lot of limitations during the perioperative period, which can be overcome by the three dimensional echocardiography (3D-TEE). We report a case where 3D TEE has undoubtedly delineated the cause for distortion of aortic sinus after mitral valve replacement and helped in the successful outcome.

Mitral Inflow Obstruction Resulting From a Dilated Coronary Sinus: Role of Intraoperative Transesophageal Echocardiography in Diagnosis and Surgical Repair

Mitral inflow obstruction caused by dilated coronary sinus is a rare congenital cardiac anomaly that must be differentiated from other causes of left ventricular inflow obstruction such as cor triatriatum, supramitral membrane, and supramitral ridge, because their surgical repair is different. Although preoperative transthoracic echocardiography is the primary imaging modality for diagnosis, intraoperative transesophageal echocardiography has a higher sensitivity and specificity over transthoracic echocardiography in differentiating these lesions. We report 2 cases of supramitral obstruction where the intraoperative transesophageal echocardiography has refined the preoperative diagnosis and changed the course of surgical repair.

Warden repair for superior sinus venosus atrial septal defect and anomalous pulmonary venous drainage in children: Anesthesia and transesophageal echocardiography perspectives.

Objective: Review of intraoperative anesthetic challenges and the role of transesophageal echocardiography in children with sinus venosus atrial septal defect and partial anomalous pulmonary venous drainage undergoing Warden repair. Design: A retrospective observational case series. Methodolgy: Pediatric patients who underwent Warden repair between October 2011-September 2015 were recruited. Their preoperative clinical details, anesthetic techniques, intraoperative TEE findings and postoperative events were recorded from the medical records. The categorical variables and the continuous variables were expressed as number (percentages) and mean ΁ SD respectively. Results: A total of 35 patients were operated for Warden repair during the study period. Anesthesia was induced with the aim to prevent any fall in pulmonary vascular resistance. The right internal jugular vein was cannulated under ultrasound guidance using a short length cannula to monitor right superior vena cava pressure. Intraoperative TEE revealed the drainage of PAPVC high into RSVC in 22 patients. Persistent LSVC was found in 9 patients. After repair, TEE imaging detected a high gradient at Warden anastomotic site in 5 patients and 3 of them required revision of surgery. Rerouted pulmonary veins required surgical correction in 2 patients in view of obstruction. None of them had pulmonary venous and SVC obstruction in the postoperative period. Conclusion: The primary aim of anesthesia is to avoid any fall in PVR. Right IJV cannulation can be beneficial. The intraoperative TEE can help in delineating the anatomy of lesion and detecting anastomotic site obstruction.

Redo cardiac valve surgery and severe kyphoscoliosis: Anesthetic challenges.

A transesophageal echocardiography (TEE) probe was inserted and comprehensive study was done using an ultrasound system (iE33; Philips Medical Systems). Aortic valve (AV) area was 0.72 cm2 with a peak velocity of 3.9 m/s and mean gradient (MG) of 56 mmHg. The mitral valve (MV) area was 2.16 cm2 with MG of 3 mmHg. Surgeons changed the surgical plan to AV replacement (AVR) as the TEE showed adequate MV size and acceptable MG across MV. Seventeen # St. Jude heart valve prosthesis was implanted in aortic position. Post‐cardio pulmonary bypass (CPB) TEE showed a normally functioning prosthesis with a peak velocity of 1.8 m/s, MG of 8 mmHg, and an indexed orifice area of 0.87 cm2/m2. The patient was weaned from CPB with infusion of dobutamine 5 mcg/kg/min. Trachea was extubated after 12 h of elective ventilation in the Intensive Care Unit. As postextubation blood gases showed retention of CO2, she needed noninvasive bilevel positive airway pressure for 24 h. She was discharged on the 8th postoperative day with warfarin anticoagulation.