Comparative Effect of High-Frequency Nasal Cannula and Noninvasive Ventilation on the Work of Breathing and Postoperative Pulmonary Complication after Pediatric Congenital Cardiac Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Various forms of commonly used noninvasive respiratory support strategies have considerable effect on diaphragmatic contractile function which can be evaluated using sonographic diaphragm activity parameters. OBJECTIVE: To compare the magnitude of respiratory workload decreased as assessed by thickening fraction of the diaphragm and longitudinal diaphragmatic strain while using high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) modes [nasal intermittent positive pressure ventilation (NIPPV) and bilevel positive airway pressure (BiPAP)] in pediatric patients after cardiothoracic surgery. METHODOLOGY: This prospective randomized controlled trial was performed at a tertiary care surgical intensive care unit in postcardiac surgery patients aged between 1 and 48 months, who were randomly allocated into three groups: 1) HFNC (with flows at 2 L/kg/min), 2) NIPPV via RAMS cannula in PSV mode (pressure support 8 cmH2O, PEEP 5 cmH2O), and 3) BiPAP in nCPAP mode (CPAP of 5 cmH2O). Measurements were recorded at baseline after extubation (R0) and subsequently every 12 hourly (R1, R2, R3, R4, R5) at 12, 24, 36, 48, and 60 hours respectively until therapy was discontinued. RESULTS: Sixty patients were included, with 20 patients each in the NIPPV group, HFNC group, and BiPAP group. Longitudinal strain at crura of diaphragm was lower in the BiPAP group as compared to HFNC group at R2-R4 [R2 (-4.27± -2.73 vs - 8.40± -6.40, P = 0.031), R3 (-5.32± -2.28 vs -8.44± -5.6, P = 0.015), and R4 (-3.8± -3.42 vs -12.4± -7.12, P = 0.040)]. PFR was higher in HFNC than NIPPV group at baseline and R1-R3[R0 (323 ± 114 vs 264 ± 80, P = 0.008), R1 (311 ± 114 vs 233 ± 66, P = 0.022), R2 (328 ± 116 vs 237 ± 4, P = 0.002), R3 (346 ± 112 vs 238 ± 54, P = 0.001)]. DTF and clinical parameters of increased work of breathing remain comparable between three groups. The rate of reintubation (within 48 hours of extubation or at ICU discharge) was 0.06% (1 in NIPPV, 1 in BiPAP, 2 in HFNC) and remain comparable between groups (P = 1.0). CONCLUSION: BiPAP may provide better decrease in work of breathing compared to HFNC as reflected by lower crural diaphragmatic strain pattern. HFNC may provide better oxygenation compared to NIPPV group, as reflected by higher PFR ratio. Failure rate and safety profile are similar among different methods used.

Right Atrial Strain in Pediatric Pulmonary Hypertension-A Prospective Observational Study.

Right ventricular (RV) afterload due to elevated pulmonary arterial (PA) pressure in pulmonary hypertension (PH) causes long-term right atrial (RA) remodeling and dysfunction. RA function has been shown to correlate with PA pressures and outcome in both adult and pediatric patients with PH. We studied the role of RA strain in estimating PA pressures in congenital heart disease (CHD)-associated PH. Children below 12 years undergoing elective repair of CHD with left-to-right shunts and echocardiographic evidence of PH were included. RA reservoir, conduit and contractile strain along with conventional measures of RV function and PA pressure were measured using transthoracic echocardiography after induction of anaesthesia. Pre-and post-repair invasive PA pressures were measured after surgical exposure. 51 children with a median age of 24 months (range 4-144 months) were included, most of whom were undergoing VSD closure. Contractile RA strain showed good correlation with pre-repair systolic PA pressure in mmHg (r = 0.59, 95%CI 0.37-0.75) or expressed as a percentage of SBP (r = 0.67, 95%CI 0.49-0.80). It also predicted persistent postoperative PH as well as pre-repair pulmonary artery acceleration time and right ventricular systolic pressure measured from tricuspid regurgitation jet. The trends of correlation observed suggest a possible prognostic role of RA strain in ACHD with PH and potential utility in its echocardiographic assessment. The observed findings merit deeper evaluation in larger cohorts.

Temperature-controlled spectral tuning of a single wavelength polymer-based solid-state random laser.

We demonstrate temperature-controlled spectral tunability of a partially-pumped single-wavelength random laser in a solid-state random laser based on DCM [4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran] doped PMMA (polymethyl methacrylate) dye. By carefully shaping the spatial profile of the pump, we first achieve a low-threshold, single-mode random lasing with an excellent side lobe rejection. Notably, we show how temperature-induced changes in the refractive index of the PMMA-DCM layer result in a blue shift of this single lasing mode. We demonstrate spectral tunability over an 8nm-wide bandwidth.

Author Response.

How to cite this article: Niyogi SG, Naskar C, Singh A, Kumar B, Grover S. Author Response. Indian J Crit Care Med 2024;28(2):188.

Melatonin and Melatonin Agonists for Prevention of Delirium in the Cardiac Surgical ICU: A Meta-analysis.

Aim and Background: Delirium is highly prevalent in the immediate postoperative period following cardiac surgery and adversely impacts outcomes. Melatonin has been increasingly used in pharmacological prevention of delirium. We aimed to synthesize the available evidence concerning the role of melatonin and melatonin agonists in preventing delirium in patients after cardiac surgery. Materials and methods: PubMed, Google Scholar, and Web of Science databases were searched for relevant randomized and non-randomized trials in adults undergoing cardiac surgery investigating melatonin agonists to prevent delirium. Studies incorporating transplants, preoperative organ support, prophylactic antipsychotics, or children were excluded. Risk-of-bias was assessed using Cochrane ROB 2.0 and ROBINS-I tools. A systematic review and meta-analysis were conducted, calculating pooled odds ratio (OR) for the incidence of postoperative delirium using a random effects model with the Mantel-Haenszel method with restricted maximum-likelihood estimator. Trial sequential analysis was also carried out for the primary outcome. Results: Six randomized trials and one non-randomized trial involving 1,179 patients were included. Incidence of delirium was 16.7 and 29.6% in the intervention and comparator groups respectively, indicating a pooled OR of 0.44 [95% confidence interval (CI) 0.27 - 0.71, p = 0.04] favoring melatonin. Two studies had a high risk of bias, and I2 statistics indicated significant heterogeneity. However, publication bias was insignificant, and trial sequential analysis indicated the significance of the attained effect size. Conclusion: Based on available studies, perioperative melatonin use significantly decreases postoperative incidence of delirium after adult cardiac surgery. However, the available quality of evidence is low, and larger trials with standardization of nonpharmacological delirium prevention interventions, in high-risk cohorts, and exploring various dosages and regimens should be carried out. How to cite this article: Niyogi SG, Naskar C, Singh A, Kumar B, Grover S. Melatonin and Melatonin Agonists for Prevention of Delirium in the Cardiac Surgical ICU: A Meta-analysis. Indian J Crit Care Med 2023;27(11):837-844.

2D tunable all-solid-state random laser in the visible.

A two-dimensional (2D) solid-state random laser emitting in the visible is demonstrated, in which optical feedback is provided by a controlled disordered arrangement of air-holes in a dye-doped polymer film. We find an optimal scatterer density for which threshold is minimum and scattering is the strongest. We show that the laser emission can be red-shifted by either decreasing scatterer density or increasing pump area. We show that spatial coherence is easily controlled by varying pump area. Such a 2D random laser provides with a compact on-chip tunable laser source and a unique platform to explore non-Hermitian photonics in the visible.

Effect of perioperative use of oral triidothyronine for infants undergoing complex congenital cardiac surgeries under cardiopulmonary bypass: A double-blinded randomised controlled study.

Background: Thyroid hormone metabolism disrupts after cardiopulmonary bypass both in adults and pediatric patients. This is known as Euthyroid sick syndrome, and it is more evident in pediatric patients who were undergoing complex cardiac surgeries compared to adults. This decrease in serum T3 levels increases the incidence of low cardiac output, requirement of inotropes, prolonged mechanical ventilation, and prolonged intensive care unit (ICU) stay. Aims and Objectives: The primary objective was to compare the mean Vasoactive-inotropic score (VIS) at 72 hours postoperatively between T3 and Placebo groups. Materials and Methods: One hundred patients were screened, and 88 patients were included in the study. Triidothyronine 1 mic/kg 10 doses 8th hourly was given orally postoperatively to cases and sugar sachets to controls. The blood samples for analysis of FT3, FT4, and TSH were taken every 24 hours postoperatively, and baseline values were taken after induction. Mean VIS scores, ejection Fraction (EF), Left ventricular outflow tract velocity time integral (LVOT VTi), hemodynamics and partial pressure of oxygen/ fraction of inspired oxygen(PaO2/FiO2) were recorded daily. Results: The Mean VIS scores at 72 Hours postoperatively were significantly less in the T3 group (5.49 ± 6.2) compared to the Placebo group (13.6 ± 11.7). The PaO2/FiO2 ratios were comparatively more in the T3 group than the Placebo group. The serum levels of FT3 FT4 were significantly higher in the T3-supplemented group than the Placebo group. The VIS scores were significantly lower from 48 hours postoperatively in children < 6 months of age. Conclusion: In this study, we observed that supplementing T3 postoperatively decreases the ionotropic requirement from 72 hours postoperatively. This is more useful in children <6 months of age undergoing complex cardiac surgeries.

Utility of Transfontanelle Ultrasound in Predicting the Fluid Responsiveness in Children After Repair of Congenital Heart Diseases: A Prospective Observational Study.

OBJECTIVES: Postoperative fluid management in children undergoing cardiac surgery requires a balanced optimization. The blood flow velocity variation in the internal carotid artery (ΔICA) measured through transfontanelle ultrasound has been shown to predict fluid responsiveness during cardiac surgery. It may provide an excellent window to study fluid responsiveness in infants during the postoperative period when the intensivist is faced with the challenges of poor echocardiographic window. The authors aimed to observe the correlation between ΔICA measured on transfontanelle ultrasound with the respiratory variability of peak aortic blood flow velocity (ΔVpeak) on transthoracic echocardiography as a marker of fluid responsiveness in infants on mechanical ventilation during the postoperative period after cardiac surgery. DESIGN: A prospective observational study. SETTING: The postcardiac surgery intensive care unit (ICU) of a tertiary care hospital. PARTICIPANTS: Thirty infants undergoing congenital cardiac surgery. INTERVENTIONS: A fluid bolus of 10 mL/kg administered over 10 minutes at 1 and 6 hours after ICU admission. Patients were categorized into fluid responders and nonresponders based on >15% increase in the indexed stroke volume. MEASUREMENTS AND MAIN RESULTS: A total of 50 fluid boluses were administered in 30 patients. Among these, 22 (73.33%) were responders and 8 (26.67%) were nonresponders. There was moderate correlation between ΔICA and peak aortic blood flow velocity variation (ΔVpeak) (r = 0.59, p ≤ 0.001). The ΔVpeak >14.74% had 68% sensitivity and 75% specificity to predict fluid responsiveness (area under the receiver operating characteristic [AUROC], 0.749; p = 0.001; positive likelihood ratio, 2.71; negative likelihood ratio, 0.43). The ΔICA >9.85% could predict fluid responsiveness in infants (AUROC, 0.728; p = 0.003; 75% sensitivity; 60% specificity; positive likelihood ratio, 1.85; negative likelihood ratio, 0.42). Among children younger than 6 months, ΔICA >9.85% was a better predictor of fluid responsiveness (AUROC, 0.889; p = 0.009) than ΔVpeak >15% (AUROC, 0.778; p = 0.061). CONCLUSION: The ICA variability >9.85% measured via transfontanelle ultrasound is a good predictor of fluid responsiveness in infants, especially those younger than 6 months on mechanical ventilation after cardiac surgery.

Role of transesophageal echocardiography in the recurrent biatrial myxoma of uncommon origin.

After surgical excision of myxoma recurrence usually happens adjacent to the initial origin site. We report a case of recurrent myxomas in a young male patient that had biatrial recurrence with one tumor originating very unusually from the base of the anterior mitral leaflet. Intraoperative transesophageal echocardiography was instrumental in localizing the site of the origin of left atrial myxoma from the base of the anterior mitral leaflet and in detecting an additional myxoma attached to the wall of the right atrium.

Utility of Lung Ultrasound in the Estimation of Extravascular Lung Water in a Pediatric Population-A Prospective Observational Study.

OBJECTIVE: Lung ultrasound (LUS) is a promising bedside modality for the estimation of extravascular lung water index (EVLWI), but has not been validated against objective measures in children. This study aimed to investigate the correlation of LUS B-line scoring with EVLWI, thresholds indicating elevated EVLWI, and its outcome following pediatric cardiac surgery. DESIGN: Prospective observational study. SETTING: Cardiothoracic surgical intensive care unit in a tertiary care teaching hospital. PARTICIPANTS: Children younger than 12 years undergoing elective complete surgical correction of cyanotic or acyanotic congenital heart disease (Aristotle score ≤9), excluding neonates, those weighing <3.5 kg, and those with thoracic deformities, pulmonary pathology, and hemodynamic instability. INTERVENTIONS: Extravascular lung water index measurement by transpulmonary thermodilution, along with concurrent LUS B-line and Chest-X ray (CXR) scoring. MEASUREMENTS AND MAIN RESULTS: LUS B-line score had a moderate correlation with EVLWI (Pearson's correlation coefficient 0.57; 95% CI 0.44-0.69). LUS B-line scores showed acceptable discrimination only for higher thresholds of EVLWI (sensitivity 82% and 79%, respectively, for EVLWI >20 mL/kg v sensitivity and specificity 57% and 80% for EVLWI >10 mL/kg). Age, body surface area, vasoactive-inotropic score (VIS), chest X-ray score, and EVLWI but not LUS B-line score were significant predictors for duration of mechanical ventilation in this cohort. CONCLUSIONS: LUS B-line scoring has limited utility in semiquantitative estimation of EVLWI at lower thresholds of EVLWI in pediatric cardiac surgical patients. It may have better discrimination and acceptable sensitivity and specificity at higher thresholds of EVLWI. Contrasting with multiple reports of clinical utility, these results call for wider evaluation of LUS and its clinical modifiers like age, pathology, and pretest probability in estimation of EVLWI.

Iatrogenic aortic regurgitation following percutaneous coronary intervention: Role of transesophageal echocardiography in the detection and management.

The incidence aortic valve injury during percutaneous coronary intervention is scarce, mostly resulting in acute aortic regurgitation. However, rarely patients may remain asymptomatic in the immediate post-procedure period and present latter with chronic aortic regurgitation. Determining etiology of such an aortic regurgitation may be challenging. We present a case of a 51-year-old man with history of percutaneous coronary intervention for coronary artery disease and moderate aortic regurgitation scheduled for coronary artery bypass grafting and aortic valve replacement. Intra-operative transesophageal echocardiography was instrumental in deciding etiology of aortic regurgitation that change surgical management of the patient.

Natural DNA assisted white light generation and stimuli responsive colour tuning.

The unique structure of a natural nucleic acid, calf thymus DNA, which can provide an appropriate scaffold for an efficient cascaded energy transfer among organic chromophores, has been used for the generation of bright and pure white light on UV light excitation. Two most commonly used DNA stains, 4',6-diamidino-2-phenylindole (DAPI) and ethidium bromide (EB) have been used as a part of the donor-acceptor pairs. We have judiciously selected 10-anthracene-10-yl-3-methylbenzothiazol-3-ium chloride (AnMBTZ), an ultrafast molecular rotor, to act as a bridge between DNA bound DAPI and EB for the cascaded flow of energy. The unique molecular rotor properties of AnMBTZ and its exceptional binding ability with natural DNA help to form a distinct tri-chromophoric system in DNA template which can produce bright and pure white light on UV excitation. Detailed flow of energy from photoexcited DAPI to EB via AnMBTZ has been explored using steady state and time-resolved emission spectroscopy. Further, unique binding nature of AnMBTZ with DNA molecules has been used to modulate the colour of the emission from the present tri-chromophoric system by external stimuli, like salt and temperature. Such unique stimuli responsive multi-chromophoric system in a bio-template has great potential for different lightening applications.

Role of Lung Ultrasound in the Detection of Postoperative Pulmonary Complications in Pediatric Patients: A Prospective Observational Study.

OBJECTIVE: To evaluate the incremental benefit of lung ultrasound (LUS) over clinical examination and chest x-rays (CXR) together (clinico-radiologic examination) for the diagnosis of postoperative pulmonary complications (PPC). DESIGN: Prospective observational study. SETTING: Tertiary care center. PARTICIPANTS: One hundred children after corrective congenital cardiac surgery with left-to-right shunts. INTERVENTION: Participants were independently evaluated with clinico-radiologic examination by the treating team, as well as LUS by an investigator at 12, 24, 48, and 72 hours after surgery. After recording the diagnoses, the LUS findings were disclosed to the treating team and a final diagnosis was made. CXR scores and LUS scores were evaluated for their ability to predict PPC. MEASUREMENTS AND MAIN RESULTS: A total of 34 cases of PPCs were observed. Of these, 32 each were detected by clinico-radiologic examination and LUS alone. Addition of LUS improved total number of PPCs detected in the early postoperative period but not in the late postoperative period. Preoperative and early postoperative LUS scores were superior to CXR scores in predicting occurrence of PPC (area under receiver operating characteristics curve [AUROC] 0.920 v 0.732; p < 0.001 preoperatively; AUROC 0.987 v 0.858, p = 0.001 at 12 hours postoperatively). Multivariate analysis suggested LUS score as an independent predictor of PPC, and LUS score along with aortic cross-clamp time as independent predictors of duration of mechanical ventilation and intensive care unit stay. CONCLUSIONS: LUS improves identification of PPC over clinico-radiologic examination in the early postoperative period. Preoperative LUS scores have better predictive ability than CXR scores for the occurrence of PPC.

Intraoperative transesophageal echocardiography: A complement to 18F-fluorodeoxyglucose positron emission tomography-computed tomography in localizing pacemaker lead endocarditis.

Lead endocarditis (LE) is a serious complication of permanent trans-venous pacing. Localizing LE may be challenging with conventional imaging modalities. 2-deoxy-2-[fluorine-18] fluoro-D-glucose positron emission tomography-computed tomography (FDG PET/CT) has recently emerged as a promising tool in the diagnosis of LE particularly in cases with normal echocardiographic imaging findings and/or negative blood culture. However, this technique is associated with some drawbacks. Knowledge of these drawbacks and correlating its limitations with other imaging modality is essential for the echocardiographer while evaluating such patient. We report a case where transesophageal echocardiography was complementary to FDG PET/CT in the diagnosis and localization of vegetation over pacemaker leads during intraoperative period.

Left Atrial Dissection and Rupture Following Excision of Left Atrial Myxoma: Role of Transesophageal Echocardiography.

Left atrial mass after excision of a left atrial myxoma may occur due to residual or additional masses, such as biatrial or multicentric myxomas and inverted left atrial appendage. In this E-challenge, the authors present a case where intraoperative transesophageal echocardiography allowed visualization of a left atrial mass after excision of a left atrial myxoma. Detailed examination demonstrated that the mass was due to left atrial dissection that progressed to rupture, allowing its early detection and repair. A high index of suspicion, as well as coordination between the surgeon and the perioperative echocardiographer, played a crucial role in the detection and management of this complication.

Systolic anterior motion of mitral valve following resection of subaortic membrane and intracardiac repair of tetralogy of fallot.

Systolic anterior motion (SAM) of the mitral valve is commonly observed in patients with hypertrophic obstructive cardiomyopathy and in few patients after mitral valve repair or aortic valve replacement. It may cause significant hemodynamic instability due to left ventricular outflow tract (LVOT) obstruction and resulting mitral regurgitation. Subaortic septal bulge is considered as a one of the risk factor for the development of SAM as it narrows the LVOT. We report a case of tetralogy of fallot with subaortic septal bulge who developed SAM of the anterior mitral leaflet, intraoperatively, after resection of a subaortic membrane.

Emergency valve preserving ascending aorta replacement following iatrogenic right coronary artery dissection: A life-saving procedure.

Iatrogenic aortocoronary dissection is a rare but potentially fatal complication of coronary catheterizations. Although the incidence is comparatively low, dissection often leads to procedure failure with increased risk of myocardial infarction and death. Iatrogenic aortocoronary dissection is principally caused by disruption of intima at the ostia of the right or left coronary artery during interventional procedures and appears as luminal filling defects, the persistence of contrast or intimal tear outside the coronary lumen. We present a case of right coronary artery dissection leading to type-A aortic dissection suffered during diagnostic coronary catheterization. This required emergency supracoronary replacement of the ascending aorta with an aortic interposition tube graft and venous grafts to coronary arteries.

Absent right superior vena cava with left superior vena cava draining into unroofed coronary sinus with common atrium in a child with an atrioventricular septal defect.

The association of absent right superior vena cava and persistent left superior vena cava draining into unroofed coronary sinus with common atrium and the atrioventricular septal defect is an extremely rare form of the congenital cardiac disorder with only one case reported so far, hence, can be missed preoperatively if not carefully looked for. Failure to detect absent right superior vena cava beforehand may otherwise pose difficulties in carrying out invasive surgical or medical interventions.

Dextrocardia, situs solitus, inlet ventricular septal defect (VSD), and iatrogenic tricuspid regurgitation (TR)-A surgical perspective.

Dextrocardia with situs solitus is a rare congenital anomaly, often associated with intra- or extracardiac malformations. A clear understanding of the spatial orientation of the chambers of the heart for planning surgical approach, is imperative. Access to the right side of the heart, especially for repair of the tricuspid valve can be challenging. We describe a case of dextrocardia, situs solitus, inlet ventricular septal defect (VSD) with iatrogenic tricuspid regurgitation (TR) in an adult patient, highlighting the surgical aspects essential for a successful outcome.