Postoperative Outcomes After Emergency Surgery in COVID-19 Patients: An Ambispective Matched Cohort Study

Purpose There is limited data from the Indian subcontinent regarding the surgical outcomes of coronavirus disease (COVID-19) patients. In this observational study, we aimed to evaluate the postoperative outcomes after emergency surgery in COVID-19 patients compared to concurrent age and gender-matched controls. We also sought to analyze the possible predictors of postoperative mortality in COVID-19 patients. Methods This matched cohort study was conducted in a tertiary care teaching hospital in central India, between 1st July 2021 and 30th June 2022. COVID-19-positive patients undergoing emergency surgery under anesthesia were recruited as cases. Age and gender-matched COVID-19-negative patients undergoing a similar nature of surgery in the same period served as concurrent controls. The cases and controls were compared for the 30-day mortality and perioperative complications. Results The COVID-19-positive surgical cohort had a 12.3 times greater 30-day postoperative overall mortality risk as compared to a matched cohort of patients with a negative COVID-19 test. A positive COVID-19 status was associated with more postoperative complications of acute respiratory distress syndrome (ARDS), sepsis, shock, and persistent hyperglycemia. On analysis of predictors of mortality, the presence of preoperative dyspnea, ARDS, American Society of Anesthesiologists Physical Status (ASA-PS) Class IIIE/IVE, increase in sequential organ failure assessment (SOFA) score, Quick SOFA>1, higher creatinine, bilirubin, and lower albumin were observed to be associated with increased mortality. Conclusions Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients undergoing emergency surgery is significantly associated with higher postoperative complications and increased 30-day postoperative mortality.

Efficacy of intertruncal and corner-pocket approaches of ultrasound-guided supraclavicular block in terms of ulnar nerve blockade: A randomised controlled study

Background and Aims

The incidence of ulnar nerve sparing has declined with the corner-pocket approach of the supraclavicular block (SCB), however, it continues to persist. A recent technique of SCB, the intertruncal approach, separately blocks each trunk of the brachial plexus. Thus, we hypothesised that the intertruncal approach results in a complete ulnar nerve blockade.

Methods

Eighty-eight patients were randomised to undergo SCB using an ultrasound (USG)-guided corner-pocket or intertruncal approach and were compared primarily regarding the complete sensory and motor blockade of the ulnar nerve and all four nerves (ulnar, radial, median and musculocutaneous nerves) at 15 min. Secondary objectives included time required for block performance, patient discomfort score, time to readiness for surgery and duration of sensory blockade of the ulnar nerve. Continous data were compared using an independent t-test, and categorical data were compared using the Chi-square test.

Results

The proportion of participants with complete sensory (30/44 vs. 14/44, P < 0.001) and complete motor (22/44 vs. 7/44, P < 0.001) blocks in the ulnar nerve and all four nerves at 15 min was significantly higher in the intertruncal group. Block performance time and patient discomfort score were higher in the intertruncal group (P < 0.001). The total duration of sensory blockade in the ulnar nerve was more in the corner-pocket group (P < 0.001).

Conclusion

USG-guided intertruncal approach is superior to the corner-pocket approach of SCB regarding a complete ulnar nerve blockade.

Diagnostic efficacy of chest CT imaging in diagnosis of COVID-19 cases based on duration of symptoms

Background

Chest computed tomography (CT) imaging provides results more rapidly and with higher sensitivity than reverse transcription polymerase chain reaction in diagnosis of COVID-19.

Aim

To evaluate diagnostic efficacy of chest CT imaging in diagnosis of COVID-19 cases based on age and duration of symptoms.

Materials and Methods

A retrospective study conducted during December 2020 to June 2021 in a tertiary care hospital, India. Total 495 patients with typical clinical symptoms of COVID-19, reverse transcription polymerase chain reaction positive for COVID-19 and had undergone chest CT imaging were included. Descriptive statistical analysis was performed for all the variables. Receiver operating characteristic curve analysis was used to determine threshold value of chest CT severity score (CT_SS) based on duration of symptoms and age to diagnose COVID-19.

Results

Mean age of patients was 61.86 ± 10.77 years and 367 (71.4%) patients were male. Ground glass opacities were observed in 456 (92.1%) patients and in 332 (67.1%) patients, multilobes were affected. Total CT_SS showed positive correlation with age (r = 0.257) and duration of symptoms (r = 0.625). Total CT_SS >6 after a duration of 2 days of symptoms identified COVID-19 cases with sensitivity 90.8% (95% confidence interval [CI]: 87.5%-93.5%) and specificity 84.6% (95% CI: 76.2%-90.9%). Total CT_SS >11 in patients aged more than 60 years identified COVID-19 cases with sensitivity 47.4% (95% CI: 41.2%-53.6%) and specificity 87.3% (95% CI: 82.3%-91.4%).

Conclusion

Threshold value of CT_SS determined will help to expedite diagnosis of COVID-19 patients by the clinicians in an early stage especially in India and other developing countries which have a high patient volume and limited health resources.

Intramuscular ketamine provides better sedation and scan conditions in children undergoing magnetic resonance imaging: A single-blinded observational study

Objectives

The objectives of this study were to compare the quality of sedation provided by intravenous (i.v.) and intramuscular (im) ketamine for pediatric magnetic resonance imaging (MRI).

Materials and Methods

This study was a non-randomized, single-blinded, and prospective observational study. After receiving approval from the Institutional Ethics Committee, a total of 108 children aged 2-7 years were divided into two groups, with 54 children in each group. In the i.v. group, children received ketamine at a dose of 1.5 mg/kg intravenously, while in the im group, children received ketamine at a dose of 4 mg/kg intramuscularly. If a Ramsay sedation score of 6 (RSS-6) was not achieved, half of the loading dose of ketamine was repeated. In both groups, rescue propofol boluses of 1 mg/kg intravenously were administered whenever the child moved. The primary outcome measure was the quality of sedation, which was assessed by a blinded radiologist. The time taken to reach RSS-6, the number of rescue propofol boluses, the total time wasted in taking repeat sequences, and the time required to achieve a modified Aldrete score of 9 (MAS-9) were recorded.

Results

The im group demonstrated significantly better sedation quality. In the i.v. group, the time to achieve RSS-6 was significantly shorter, but it required more rescue propofol boluses to maintain sedation. The i.v. group also experienced a notable increase in the total time wasted during repeat sequences. On the other hand, the i.v. group exhibited a shorter time to reach MAS-9 compared to the im group.

Conclusion

The im group showed superior sedation quality when compared to the i.v. group. However, it is important to consider that the im group experienced a longer recovery time.

Case Report of Male Pseudohermaphroditism (Androgen Insensitivity Syndrome): Congenital Disorder of Sexual Differentiation

INTRODUCTION

A broad spectrum of anomalies of sexual differentiation may exist at birth, which can be unreported until adolescence. A 17-year-old patent with female phenotype came with complaints of primary amenorrhea. On imaging (ultrasound and MRI) uterus and bilateral ovaries were absent. Small blind-ending vaginal pouch was noted along with features suggesting bilateral cryptorchidism. No definite male external genitalia/scrotal sac was seen except for subtle rudimentary bulbo-cavernous muscles. Karyotyping confirmed 46 XY consistent with Male Pseudohermaphroditism.

MATERIALS

Male pseudohermaphroditism refers to a condition that affects 46, XY individuals with differentiated testes who exhibit varying degrees of feminization. In these cases there is a spectrum of external genitalia; some individuals are completely phenotypically female. Androgen insensitivity syndrome (AIS), also known as the testicular feminization syndrome, results from end-organ resistance to androgens, particularly testosterone. As the appearance of the external genitalia often is not distinctive enough to make a specific diagnosis, this must be accomplished by clinical findings along with a combination of imaging, cytogenetic and biochemical studies. Ultrasound and MRI studies are extremely useful to diagnose such conditions at the earliest as these patients have an increased incidence of malignancy in the undescended testes. The treatment is influenced by genital tissue responsiveness to androgens and reconstructive surgical procedures. There is a need for counselling regarding pubertal development, sexual performance and fertility.

RESULT

A 17year old patent came with complaints of primary amenorrhea. On examination patient has normal external female genitalia, with developed breast. On laboratory correlation, it shows high testosterone level: 881 ng/dL and Normal progesterone level: 0.182 ng/mL. On karyotyping, it shows 46XY karyotype. On USG: Uterus is not well appreciated. There is iso-echogenic oval shaped soft tissue seen in bilateral inguinal regions with vascularity within-likely to be gonads. On MRI: Absence of uterus and bilateral ovaries are confirmed with evidence of symmetrical oval-shaped soft tissue lesions identified within bilateral inguinal canals - consistent with bilateral cryptorchidism. Male pseudohermaphroditism refers to a condition that affects 46, XY individuals with differentiated testes who exhibit varying degrees of feminization.

CONCLUSION

In cases of male pseudohermaphroditism, there is a spectrum of external genitalia; some individuals are completely phenotypically female, whereas others appear to be normal males with varying spermatogenesis and/or pubertal virilization. As the appearance of the external genitalia often is not distinctive enough to make a specific diagnosis, this must be accomplished by clinical findings along with a combination of cytogenetic, biochemical, and radiologic studies. Sonographic and radiographic studies are often used initially to evaluate such conditions. Male pseudohermaphrodites all possess testes yet exhibit incomplete virilization of the genital ducts and/or external genitalia. The findings depend on the underlying defect. Complete androgen insensitivity (testicular feminization) is an X-linked recessive disorder in which the absence of cytoplasmic testosterone receptors prevents specific gene activation and subsequent differentiation of the external genitalia. In this disorder, the external genitalia are completely feminized, while in the other forms of male pseudohermaphroditism various degrees of virilization occur. The absence of internal female genital tract structures reflects the synthesis of active Mullerian regression factor by the testes, which may be maldescended. Multiplanar MR images will confirm the absence of a uterus and demonstrate intraabdominal or inguinal testes. Integrated imaging in the form of ultrasound, genitography and MRI is important in demonstrating the anatomy, classification, possible effects or congenital malformations in other organs, warning patients of any risk of neoplasia and guiding the clinician to plan other investigations, hormonal replacement or reconstruction surgery if required. References Tanaka YO, Mesaki N, Kurosaki Y, et al. Testicular feminization: role of MRI in diagnosing this rare male pseudohermaphroditism. J Comput Assist Tomogr 1998;22(6):884-888. Nakhal RS, Hall-Craggs M, Freeman A, et al. Evaluation of retained testes in adolescent girls and women with complete androgen insensitivity syndrome. Radiology 2013;268(1):153-160.

A Rare Cause of Gross Hematuria Due to Placing a Patient with Distended Bladder in Prone Position

How to cite this article: Seema S, Trivedi S, Padala SRAN, Kiran M. A Rare Cause of Gross Hematuria Due to Placing a Patient with Distended Bladder in Prone Position. Indian J Crit Care Med 2023;27(1):73-74.

(Cd,Mg)Te crystals for picosecond-response optical-to-x-ray radiation detectors

We demonstrate a photodetector sensitive to both optical and x-ray picosecond pulses based on our in-house grown cadmium magnesium telluride (Cd,Mg)Te single crystal. Specifically, we developed In-doped Cd_0.96Mg_0.04Te material and discuss its femtosecond optical photoresponse, as well as the detector performance, such as <100-pA dark current and up to 0.22-mA/W responsivity for 780-nm wavelength optical radiation. The detector exposed to Ti fluorescence (K alpha) x-ray pulses at 4.5 keV, generated by a free-electron laser beam with the central energy of 9.8 keV and <100 fs pulse width, exhibited readout-electronics-limited 200-ps full-width-at-half-maximum photoresponse, demonstrating that it is suitable for coarse timing in free-electron laser x-ray/optical femtosecond pump-probe spectroscopy applications.

Diversity of rumen microbiota using metagenome sequencing and methane yield in Indian sheep fed on straw and concentrate diet

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Bacteroidetes and Firmicutes were most prevalent bacteria in the sheep rumen.

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Bacteroidetes were negatively correlated with the Euryarchaeota.

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Archaea constituted ∼2.5% of the ruminal microbiota.

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Methanobrevibacter gottschalkii constituted > 50% of the ruminal archaea.

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Hydrogenotrophic methanogens distribution leads to the variability in methane yield.

An in vivo study aiming to investigate the rumen methanogens community structure was conducted in Mandya sheep fed on straw and concentrate diet. The ruminal fluid samples were collected and processed for unravelling the rumen microbiota and methanogens diversity. Further, the daily enteric methane emission and methane yield was also quantified using the SF₆ tracer technique. Results indicated that the Bacteroidetes (∼57%) and Firmicutes (25%) were two prominent affiliates of the bacterial community. Archaea represented about 2.5% of the ruminal microbiota. Methanobacteriales affiliated methanogens were the most prevalent in sheep rumen. The study inveterate that the ruminal archaea community in sheep is composed of 9 genera and 18 species. Methanobrevibacter represented the largest genus of the archaeome, while methylotrophs genera constituted only 13% of the community. Methanobrevibacter gottschalkii was the prominent methanogen, and Methaobrevibacter ruminantium distributed at a lower frequency (∼2.5%). Among Methanomassiliicoccales, Group 12 sp. ISO4-H5 constituted the most considerable fraction (∼11%). KEGG reference pathway for methane metabolism indicated the formation of methane through hydrogenotrophic and methylotrophic pathways, whereas the acetoclastic pathway was not functional in sheep. The enteric methane emission and methane yield was 19.7 g/d and 20.8 g/kg DMI, respectively. Various species of Methanobrevibacter were differently correlated, and the distribution of hydrogenotrophic methanogens mainly explained the variability in methane yield between the individual sheep. It can be inferred from the study that the hydrogenotrophic methanogens dominate the rumen archaeal community in sheep and methylotrophic/aceticlastic methanogens represent a minor fraction of the community. Further studies are warranted for establishing the metabolic association between the prevalent hydrogenotrophs and methylotrophs to identify the key reaction for reducing methane emission.

Undiagnosed laryngocele: an airway emergency

Laryngoceles are rare dilated laryngeal saccules that can present as acute airway obstruction and lead to airway emergencies. A man, presented to the emergency room, with difficulty in breathing and change in voice. An unevaluated pulsatile swelling was present on the left side of neck. Since, the patient was in stridor, an awake fiberoptic bronchoscopy (FOB)-guided intubation was planned with readiness for emergency tracheostomy, if needed. On FOB, an edematous supraglottic area with a narrowed glottic opening was observed. The procedure was abandoned and a surgical tracheostomy was performed to secure the airway. Postoperative contrast-enhanced CT neck revealed a huge laryngocele in left cervical region. We recommend that a high index of suspicion for presence of laryngocele should be kept in mind when a patient presents with stridor with pulsatile neck swelling. Timely aspiration of laryngocele may help in amelioration of the respiratory distress avoiding emergency tracheostomy.

Weaning Outcomes and 28-day Mortality after Tracheostomy in COVID-19 Patients in Central India: A Retrospective Observational Cohort Study

Background

Tracheostomy is integral in long-term intensive care of coronavirus disease-2019 (COVID-19) patients. There is a paucity of studies on weaning outcomes and mortality after tracheostomy in COVID-19 in Indian scenario.

Materials and methods

We conducted a retrospective, single-center, observational study of severe COVID-19 patients who underwent elective tracheostomy (n = 65) during critical care in a tertiary care institute in Central India from May 1, 2020, to April 30, 2021. Data were collected from Medical records, ICU charts, and follow-up visits by patient. A primary objective was to study the clinical characteristics, tracheostomy complications, weaning outcomes, and mortality at 28 and 60 days of ICU admission. We categorized the cohort into two groups (deceased and survivor) and studied association of clinical parameters with 28-day mortality. Cox Proportional regression analysis was applied to calculate the hazard ratio among the predictors of mortality with p value <0.05 as significant.

Results

Elective tracheostomy was done in 69 of 436 (15.8%) patients on invasive mechanical ventilation, of which 65 were included. Tracheostomy was percutaneous in 45/65 (69%) and surgical in 20/65 (31%) with timing from intubation as early in 41/65 and late in 24/65 with most common indication as weaning failure followed by anticipated prolonged ventilation. Tracheostomy complications were present in 29/65 (45%) patients with no difference in complication rates between timing and type of tracheostomy. Downsizing, decannulation, and weaning were successful in 22%, 32 (49%), and 35/65 (54%) patients after tracheostomy. The 28-day mortality was 30/65 (46%). The fractional inspired oxygen concentration (FiO₂) requirement in survivors was lower (0.4–0.6, p = 0.015) with a higher PaO₂/FiO₂ ratio (118–200, p = 0.033). Early tracheostomy within 7 days of intubation was not associated with weaning or survival benefit.

Conclusions

We suggest that tracheostomy should be delayed to after 7 days of intubation, especially till FiO₂ reduces to 0.5 with improvement in PaO₂/FiO₂ for better outcomes and avoiding a wasted procedure (CTRI/2021/07/034768).

Study Highlights

Tracheostomy is integral in care of COVID-19 patients needing prolonged ventilation. There is no difference in complications in early/late or percutaneous dilatational/surgical technique. We observed successful weaning post-tracheostomy in 54% patients. Mortality at 28 days was 46%. Early tracheostomy within 7 days of intubation did not improve weaning or survival.

How to cite this article

Karna ST, Trivedi S, Singh P, Khurana A, Gouroumourty R, Dodda B, et al. Weaning Outcomes and 28-day Mortality after Tracheostomy in COVID-19 Patients in Central India: A Retrospective Observational Cohort Study. Indian J Crit Care Med 2022;26(1):85–93.

Performance of prognostic scores in prediction of 30-day postoperative mortality in COVID-19 patients after emergency surgery: A retrospective cohort study

Background

: Risk assessment with prognostic scoring, though important, is scarcely studied in emergency surgical patients with COVID-19 infection.

Methods and Material

We conducted a retrospective cohort study on adult emergency surgical patients with COVID-19 infection in our institute from 1 May 2020 to 31 October 2021 to find the 30-day postoperative mortality and predictive accuracy of prognostic scores. We assessed the demographic data, prognostic risk scores (American Society of Anesthesiologists-Physical Classification (ASA-PS), Sequential Organ Failure Assessment (SOFA), Quick SOFA (qSOFA), Physiologic and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) and Portsmouth-POSSUM (P-POSSUM) scores), surgical and anesthetic factors. We assessed the postoperative morbidity using the Clavien-Dindo scale and recorded the 30-day mortality. Correlation of prognostic scores and mortality was evaluated using Univariate Cox proportional hazards regression, receiver operating characteristic curve (ROC), Youden's index and Hosmer- Lemeshow goodness of fit model.

Results

Emergency surgery was performed in 67 COVID-19 patients with postoperative complication and 30-day mortality rate of 33% and 19%, respectively. A positive qSOFA and ASAPS IIIE/IVE had a 9.03- and 12.7-times higher risk of mortality compared to a negative qSOFA and ASA-PS IE/IIE (P &lt; 0.001), respectively. Every unit increase of SOFA, POSSUM and P-POSSUM scores was associated with a 50%, 18% and 17% higher risk of mortality, respectively. SOFA, POSSUM and P-POSSUM AUCROC curves showed good discrimination between survivors and non-survivors (AUC 0.8829, 0.85 and 0.86, respectively).

Conclusions

SOFA score has a higher sensitivity to predict 30-day postoperative mortality as compared to POSSUM and P-POSSUM. However, in absence of a control group of non-COVID-19 patients, actual risk attributable to COVID-19 infection could not be determined.

Observational study to compare the effect of altitude on cardiopulmonary reserves of different individuals staying more than 6 weeks at 10,000 ft and 15,000 ft

Background

The variation in heights beyond high altitude has different effects on the cardiorespiratory profile of individuals because of variation in oxygen density with every thousand feet. This study was planned to analyze and compare the effects of difference in altitudes on cardiorespiratory profile from anesthesiologist's point of view.

Methods

A multicenter observational study was done involving two different groups of 600 patients at 10,000 ft (Group A) and 15,000 ft (Group B). Observation and comparison of oxygen saturation, 6-min walk test, and breath holding time was carried out.

Results

Fifty-five percent of subjects in Group A had oxygen saturation of more than 93% in comparison to 5.5% in Group B. This was statistically significant (P < 0.001). Two percent of subjects in Group A in comparison to 63.5% of Group B had oxygen saturation of less than 88% (P < 0.001). Percentage increase of more than 15% of heart rate was found to be statistically significant in all the age groups. Overall, 3.8% of individuals in Group A had breath holding time less than 15 s in comparison to 16.6% of individuals in Group B (P value < 0.001).

Conclusion

The study demonstrates that there is a significant fall in oxygen saturation, significant rise in the heart rate in 6-min walk test, and significant fall in the breath holding time in the group located at 15,000 ft. Heights beyond 10,000 ft should be restricted to life and limb saving surgeries, and logistics should be focused more on "scoop and run" than "stay and play" policy.

Comparison of enteric methane yield and diversity of ruminal methanogens in cattle and buffaloes fed on the same diet

An in vivo study was conducted to compare the enteric methane emissions and diversity of ruminal methanogens in cattle and buffaloes kept in the same environment and fed on the same diet. Six cattle and six buffaloes were fed on a similar diet comprising Napier (Pennisetum purpureum) green grass and concentrate in 70:30. After 90 days of feeding, the daily enteric methane emissions were quantified by using the SF6 technique and ruminal fluid samples from animals were collected for the diversity analysis. The daily enteric methane emissions were significantly greater in cattle as compared to buffaloes; however, methane yields were not different between the two species. Methanogens were ranked at different taxonomic levels against the Rumen and Intestinal Methanogen-Database. The archaeal communities in both host species were dominated by the phylum Euryarchaeota; however, Crenarchaeota represented <1% of the total archaea. Methanogens affiliated with Methanobacteriales were most prominent and their proportion did not differ between the two hosts. Methanomicrobiales and Methanomassillicoccales constituted the second largest group of methanogens in cattle and buffaloes, respectively. Methanocellales (Methanocella arvoryza) were exclusively detected in the buffaloes. At the species level, Methanobrevibacter gottschalkii had the highest abundance (55-57%) in both the host species. The relative abundance of Methanobrevibacter wolinii between the two hosts differed significantly. Methanosarcinales, the acetoclastic methanogens were significantly greater in cattle than the buffaloes. It is concluded that the ruminal methane yield in cattle and buffaloes fed on the same diet did not differ. With the diet used in this study, there was a limited influence (<3.5%) of the host on the structure of the ruminal archaea community at the species level. Therefore, the methane mitigation strategies developed in either of the hosts should be effective in the other. Further studies are warranted to reveal the conjunctive effect of diet and geographical locations with the host on ruminal archaea community composition.

The Effect of Normal Saline and Plasmalyte on Acid-Base Status in Patients Undergoing Head-and-Neck Surgery with Free Flap Reconstruction: A Prospective, Observational Cohort Study

Background

Intraoperative fluid strategy may affect the graft viability in head-and-neck surgeries with free flap reconstruction (HNS-FFR). Studies to guide regarding association of intraoperative fluid with metabolic parameters during such surgeries are infrequent.

Aim

This study aimed to compare plasmalyte (PL) and normal saline (NS) (0.9%) in terms of acid-base balance and electrolytes in the peri-operative period along with graft viability during above-mentioned surgeries.

Settings and Design

Prospective, observational cohort study was conducted in patients, 18-65 years, undergoing HNS-FFR at a tertiary care center.

Materials and Methods

The cohort was categorized into two groups based on the intraoperative fluid used, i.e., PL (Group A) and NS (Group B) group. The primary objective was to compare arterial blood gas parameters at seven time points till the 3^rd postoperative day. We studied the effect on graft viability and length of hospital stay.

Statistical Analysis Used

The independent t-tests, Chi-square, or Fisher's exact test were used to evaluate the categorical variables with a repeated measures analysis of variance for inter-group comparison with P < 0.05 as significant.

Results

Seventy-one (36 in Group A and 35 in Group B) patients were included in the study with comparable baseline characteristics. Group A had a better acid-base status, especially after the conclusion of vascular anastomosis (pH 7.37 ± 0.06 vs. 7.33 ± 0.04, P = 0.014) and in the postoperative period (pH 7.35 ± 0.07 vs. 7.31 ± 0.05, P = 0.013). No statistically significant difference was observed in outcome parameters between the groups.

Conclusions

PL may be preferred over NS due to better metabolic milieu during HNS-FFR surgery.

Regional cardiac dysfunction determined by radiation dose in patients with breast cancer

Background

Subclinical left ventricular (LV) dysfunction by 2D global longitudinal strain (GLS) immediately following radiotherapy (RT) and persisting at 12 months has been described in breast cancer (BC) patients. We hypothesised that persistent LV dysfunction may be regional and correlate with segmental RT.

Methods

Transthoracic echocardiograms were performed at baseline, 6 weeks and 12 months post-RT on 61 chemotherapy-naïve women with left sided BC.

Results

Anterior and anteroseptal regions received the highest radiation dose, and posterior and inferior segments the lowest radiation dose (Figure 1). Within each region, there was a progressive increase in the radiation dose received from base to apex. At 6 weeks, the greatest reduction in strain was observed in the anterior and anteroseptal regions, with the most significant reduction in strain in the apical segments. At 12 months, despite improvement in strain, the percentage reduction in strain was similar. There was a significant interaction between both region and segment, on the percentage change in strain at 6 weeks (p&lt;0.001) and at 12 months (p=0.007). Pairwise comparisons of apical to basal percentage change in strain demonstrated the most significant reductions in the anterior region at 6 weeks and 12 months (Table 1).

Conclusions

RT causes segmental myocardial dysfunction, with areas receiving the highest RT demonstrating the largest impairment in strain, with these changes persisting at 12 months. Long term correlation with adverse events is required.

Figure 1. Radiation dose by region and segment

Funding Acknowledgement

Type of funding source: None

EXPLORING THE METABOLICALLY ACTIVE RUMEN MICROBIOTA AND ITS FIBROLYTIC POTENTIAL IN CROSSBRED CATTLE FED ON FIBROUS DIET THROUGH METATRANSCRIPTOMICS

The rumen wharves conglomerate of symbiotic fibrolytic microflora with the potential to produce repertoire of carbohydrate-active enzymes to elicit the degradation of recalcitrant plant lignocellulosic complex into simpler forms that can be utilized by the host. A metatranscriptomics approach was adopted to explore the metabolically active microbiota and the transcripts involved in the deconstruction of lignocellulose in Indian crossbred cattle rumen. The experimental animals were fed with mixed diet for a period of twenty-one days and the total RNA was isolated from the rumen digesta using a modified total RNA extraction protocol. After mRNA enrichment, the cDNA libraries were subjected to sequencing under Illumina HiSeq platform and generated about 2.89 GB of raw sequences. The contig assembly was accomplished using two different tools and the redundant sequences were removed before further processing. A total of 133,930 orfs were predicted from the assembled contigs using MetaGeneMark tool and the taxonomic affiliation of orfs were achieved using MEGAN 6.0 Community Edition. A total of 17 bacterial, 5 eukaryotic and 1 archaeal phylum were identified from rumen metatranscriptomic dataset. Phylum Bacteroidetes were acknowledged as the most abundant and metabolically active rumen bacterial populations in cattle rumen with 36,414 orfs corresponding to it, followed by Firmicutes with 6,349 orfs. Further, MEGAN annotation of metatranscriptomic data at species level revealed that Prevotella brevis and Prevotella ruminicola as the most metabolically active bacterial populations representing 4,022 and 2,725 orfs each. The functional annotation of metatranscriptomic data using COG database revealed that a large number of transcripts (~16%) were corresponding to translation, ribosomal structure and biogenesis and carbohydrate transport and metabolism (15%). dbCAN annotation of rumen metatranscriptomic data identified and classified 5,267 transcripts belonging to 168 CAZyme families (GH-52%, GT-26%, CBM-14%, CE-6%, PL-2% and AA-0%). The microbial community analysis of the CAZyme encoding transcripts using M5NR database revealed that a significant proportion of CAZymes were contributed by genera Prevotella (37%) and Bacteroides (21%). The cattle rumen microbiome metatranscriptome analysis presented in this study facilitated the detection of large number of transcripts encoding diverse CAZymes that actively take part in the hydrolysis of plant lignocellulose complex that may be useful for improving livestock and biofuel generation.

Effect of silkworm (Bombyx mori) pupae oil supplementation on enteric methane emission and methanogens diversity in sheep

In vitro and in vivo studies were conducted to examine the effect of silkworm pupae oil on methane (CH₄) emission and methanogens diversity. Five graded levels (2, 4, 6, 8 and 10%) of silkworm pupae oil were tested in vitro. Eighteen Mandya adult sheep were divided into three groups. All the animals were fed on similar basal diet except the oil supplementation in test groups. Oil level for supplementation was decided on the basis of in vitro study. In vitro study indicated a reduction of 22% in CH₄ production with 2% oil supplementation. Animals in test groups were supplemented with oil (2%) either daily (CON) or intermittently (INT) on every alternate week for all the seven days. A significant reduction of 17-20% in enteric CH₄ emission (g/d) was achieved due to oil supplementation in sheep. However, No variation was established between test groups CON and INT. In present study, Methanobrevibacter was major genus contributed ∼90% of the total rumen methanogens; whilst Methanobrevibacter gottschalkii was the most abundant methanogens species. Abundance of Methanobrevibacter ruminantium was affected with the oil supplementation. It can be concluded that the silkworm pupae oil at 2% can decrease CH₄ emission by 15-20%.

P353 Structural, functional, and electromechanical alterations in patients with paroxysmal atrial fibrillation compared to healthy controls

Background and Methods

We sought to evaluate the clinical and echocardiographic differences between healthy controls and paroxysmal atrial fibrillation (AF) patients. Clinical and echocardiographic parameters (performed in sinus rhythm) in 46 paroxysmal AF patients were compared with a departmental database of 83 health controls.

Results

AF patients were older and had increased body size (Table 1). 39/46 (84%) of AF patients had hypertension and 23/46 (50%) had diabetes mellitus.

AF patients had increased left ventricular (LV) mass, and reduced diastolic function (lower e’ and increased E/e’ ratio) when compared to healthy controls. Left atrial (LA) volumes were significantly increased in the AF group. All strain parameters – reservoir, conduit, and contractile strain – were impaired in AF patients compared to controls. LA mechanical dispersion (MD) was significantly increased in AF patients. A ratio of indexed LA volume/LA reservoir strain was significantly higher in AF patients over controls.

The duration of AF had an inverse correlation with LA reservoir strain (Fig 1) (r=–0.78; p &lt; 0.001).

Conclusions

Compared to healthy controls, patients with paroxysmal AF have significant structural, functional and electromechanical alterations. LA strain is significantly impaired in paroxysmal AF and correlates with AF duration.

Table 1. Echocardiographic parameters Parameter Controls (mean ± SD) AF patients (mean ± SD) P value Age (years) 48 ± 18 58 ± 14 0.001 Body surface area (m2) 1.9 ± 0.2 2 ± 0.2 0.014 LV mass (g) 178 ± 48 223 ± 68 &lt;0.001 Average e’ velocity (cms-1) 10.3 ±2.7 8.1 ± 2.2 &lt;0.001 E/e’ 7.4 ± 1.9 9.3 ± 3.4 0.001 Indexed LA end systolic volume (ml/m2) 27.2 ± 7.1 39.0 ± 11.6 &lt;0.001 LA ejection fraction 55.2 ± 10.4 48.5 ± 14.0 0.007 LA functional index 43.7 ± 14.6 29.8 ± 14.3 &lt;0.001 LA reservoir strain (%) 34.3 ± 6.8 27.9± 8.1 &lt;0.001 LA conduit strain (%) 18.4 ± 6.2 13.5 ± 4.7 &lt;0.001 LA contractile strain (%) 15.9 ± 3.9 14.4 ± 5.5 0.007 LA mechanical dispersion (ms) 25.8 ± 9.6 30.9 ± 11.6 0.018 Indexed LA volume / Reservoir strain ratio 0.8 ± 0.3 1.6 ± 0.9 &lt;0.001 LV = left ventricular; LA = left atrium; SD = standard deviation

Abstract P353 Figure. Fig 1. AF duration vs. Reservoir strain

P970 Significant differences in atrial structural and functional parameters leading to differing mechanisms of atrial fibrillation in athletes compared to non-athletes

Methods

36 endurance athletes in sinus rhythm, with a previous history of AF (ATH-AF) were compared to age and gender matched endurance athletes with no prior history of AF (ATH), non athletes with paroxysmal AF (NONATH-AF) and age and gender matched healthy controls (CONTROL). A detailed transthoracic echocardiogram was performed with all groups in sinus rhythm, with detailed left atrial (LA) and left ventricular (LV) measurements, including strain analysis.

Results

All athletes had increased LA and LV size when compared with healthy controls (Table 1). Non athletes with paroxysmal AF had increased LA size when compared with controls. However, indexed LA/LV ratio was preserved in athletes and similar to healthy individuals, whilst AF patients had significantly increased LA/LV ratio. Athletes with AF had higher e’ velocity and lower E/e’, whereas e’ was reduced and E/e’ elevated in non-athlete AF patients.

Athletes had impaired LA reservoir and contractile strain, and reduced LV global longitudinal strain (GLS) compared with healthy controls.

Conclusions

Compared to healthy controls, athletes have reduced LA and LV strain, with preserved LV diastolic function and LA/LV ratio. In contrast, altered diastolic function with differential increase in LA volume was observed in AF patients. The increased risk of AF in athletes is likely mediated by different mechanistic processes other than an atrial myopathy consequent to diastolic dysfunction as observed in non-athletes with AF.

Table 1. LA and LV parameters Parameter ATH-AF ATH NONATH-AF CONTROL P value LVEDV indexed (ml/m2) 84 ± 12 79 ± 14 57 ± 10 51 ± 13 &lt;0.001 LVESV indexed (ml/m2) 35 ± 6 34 ± 7 25 ± 8 27 ± 33 0.02 LV ejection fraction (%) 58 ± 4 56 ± 4 56 ± 10 58 ± 8 0.586 LV global longitudinal strain (%) 19.2 ± 1.7 18.9 ± 2.1 21 ± 3.1 21.7 ± 2.9 &lt;0.001 e’ vel (cm/s) 10 ± 2 10 ± 3 8 ± 2 9 ± 2 0.007 E/e’ 5.7 ± 1.3 5.9 ± 1.8 9.1 ± 3.3 7.5 ± 1.5 &lt;0.001 LAV max indexed (ml/m2) 45 ± 11 43 ± 12 38 ± 11 27 ± 8 &lt;0.001 Indexed LAV/LVEDV ratio 0.5 ± 0.1 0.6 ± 0.2 0.7 ± 0.2 0.5 ± 0.1 &lt;0.001 LA reservoir strain (%) 27.2 ± 4.8 28.2 ± 3.7 27.9 ± 8.4 33.2 ± 7.0 &lt;0.001 LA conduit strain (%) 14.2 ± 4.5 14.4 ± 4.0 14.9 ± 5.5 16.6 ± 6.3 0.182 LA contractile strain (%) 13.0 ± 3.1 13.8 ± 3.6 13.0 ± 5.1 16.6 ± 3.1 &lt;0.001 LV = left ventricular, LAV = left atrial volume, LA = left atrial

P1504 Inter-vendor comparison of left atrial 2-dimensional strain using multilayer analysis

BACKGROUND

Left atrial strain (LAS) is increasingly being accepted as a marker of left atrial function. Different vendors utilise different techniques of measuring LAS in echocardiography.

AIMS

To determine the difference between multilayer endocardial and mid-myocardial measurements of LA strain on General Electric (GE) Echopac compared to the TOMTEC system which tracks endocardial strain.

METHODS

Peak reservoir left atrial strain (LAS) was measured on 50 healthy controls using the two different echocardiographic software packages. GE Echopac (v201) 2D-speckle tracking echocardiography technique (LV package) was used to measuremid-myocardial (GE-mid) and endocardial (GE-endo) LAS. This was compared to LAS measurement using TOMTEC (v4.6) which uses an endocardial tracking technique. LAS was measured in 4ch and 2ch views and average biplane strain measurement was obtained.

RESULTS

The mean of GE-mid LAS was 36.3 ± 6.3%, GE-endo LAS was higher with a mean of 44.1 ± 8.0%, while TOMTEC LAS was 42.1 ± 6.3 %. GE-mid and GE-endo LAS correlated well with TOMTEC LAS (r = 0.9, p &lt; 0.001 for both). On Bland-Altman Analysis, GE-mid LAS measurements were systematically lower than TOMTEC LAS (mean difference -5.77), whereas GE-endo LAS had no systematic bias (mean difference 1.99).

CONCLUSIONS

Mid-myocardial peak reservoir left atrial strain, which is routinely measured using GE Echopac software, systematically underestimates LAS as compared to TOMTEC LAS or GE endocardial LAS. This suggests that serial follow up of LAS measurements for patients should be performed on the same software.

P1783 Concealed structural abnormalities detected by 2D speckle tracking strain echocardiography persist post ablation in patients with idiopathic ventricular arrhythmias

Background

Idiopathic ventricular arrhythmias (IVA) occurs in patients without overt heart disease. 2D speckle tracking strain echocardiography parameters, including global longitudinal strain (GLS) and mechanical dispersion (MD), have been shown to predict ventricular arrhythmias. It is unclear if the abnormalities are due to structural substrate abnormality, or substrate abnormality consequent to electrical alterations. Aim: We sought to assess whether patients with IVA have impaired left ventricular (LV) strain indices, and if so, whether these persist following successful treatment with radiofrequency ablation (i.e. correction of electrical alteration). Methods: 2D strain analysis was performed (in sinus rhythm) in 23 consecutive patients with IVA (no structural heart disease by cardiac magnetic resonance imaging (MRI); Group A) prior to electrophysiological mapping/ablation, and compared to 23 age and gender matched healthy controls (Group B). Follow up echocardiography and multiday Holter monitoring was performed 12 months post ablation. Results: Baseline characteristics were similar for indexed LV end diastolic volume (EDV) and ejection fraction (EF) (p = 0.1 for both) (Table 1). LV GLS was lower (p = 0.03) and LV MD was increased (p = 0.002) in the IVA group prior to treatment. At follow up, 18 patients (78%) (Group C) remained free of ventricular arrhythmias – in these patients, LV GLS improved and was similar to controls (p = 0.217); however, LV MD remained significantly increased at 12 months compared to controls (p = 0.009). In the 5 patients (22%) (Group D) that continued to have ventricular arrhythmias at follow up, both LV GLS (p = 0.04) and LV MD (p = 0.008) remained significantly impaired compared to controls. Conclusion: Despite demonstrable absence of structural abnormalities with cardiac MRI, 2D strain can detect subtle alterations in myocardial contraction heterogeneity. Furthermore, 12 months post successful ablation treatment, the increase in MD persists. This suggest the presence of subtle substrate abnormality that results in IVA. In uncured patients, both myocardial deformation parameters remain impaired, suggesting the need for close future surveillance of these patients. Long term follow up with greater number of patients is required to further validate these findings.

Table 1. Echocardiographic parameters Group Indexed LVEDV (ml/m2) LVEF (%) LV GLS (%) LV MD (ms) IVA (Group A) 55 ± 15 61 ± 5 -19.9 ± 3* 44 ± 12* Controls (Group B) 54 ± 14 64 ± 7 -21.2 ± 2 33 ± 9 Group C 12 months follow up -21.7 ± 3 42 ± 11* Group D 12 month follow up -19.8 ± 2* 43 ± 11* * denotes p &lt; 0.05

Synthesis of K–Pd doped NiCo2O4−δ by reactive calcination route for oxidation of CO–CH4 emissions from CNG vehicles

The present study is devoted to formulating a doped spinel catalyst by a novel route of calcination for the oxidation of the CO–CH₄ mixture emitted from compressed natural gas (CNG) vehicles.

The longest tumor diameter in one dimension as a predictor for skeletal metastasis in renal cell carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) comprises a diverse group of malignant neoplasms that have multifarious histopathological features and biological behavior. One-third of RCC patients develops skeletal metastasis with a poor 5-year survival rate. Data explaining how some of these tumors show sooner bony metastasis than expected is sparse. The objective of this study was to identify whether tumor size can act as a predictor of bony metastases among patients of RCC.

MATERIALS AND METHODS

We retrospectively reviewed contrast enhanced computed tomography (CECT) scan and clinical records of 66 patients with RCC, who fulfilled specified inclusion criteria. Patients who had bony metastasis at the time of presentation were selected as case and those without skeletal metastasis were referred to as controls. Receiver operating characteristic (ROC) curve analysis was used to determine the appropriate cut-off value for tumor size, which was measured as the longest tumor diameter (LTD) in one-dimensional (1D).

RESULTS

Of the 66 patients selected, 30% developed bone metastasis. The tumor size of RCCs significantly correlated with the presence of skeletal metastasis in our study. None of the patients with 1D LTD <4.8 cm on CECT were found to have skeletal metastasis. ROC analysis revealed that the accuracy of the LTD in predicting bone metastasis was high with an area under ROC curve of 0.823. A cut-off value of 7.5 cm had a sensitivity of 78.9% and specificity of 80.9%.

CONCLUSION

The 1D LTD with a cut-off value of 7.5 cm, at the time of presentation is an important predictor of skeletal metastasis. The result of this study may have role in triage of patients into a subgroup which mandates more aggressive treatment and monitoring.