Purpose: The coronavirus disease-2019 (COVID-19) pandemic had affected the visiting or communicating policies for family members. We surveyed the intensive care units (ICUs) in South Asia and the Middle East to assess the impact of the COVID-19 pandemic on visiting and communication policies.

Materials and method: A web-based cross-sectional survey was used to collect data between March 22, 2021, and April 7, 2021, from healthcare professionals (HCP) working in COVID and non-COVID ICUs (one response per ICU). The topics of the questionnaire included current and pre-pandemic policies on visiting, communication, informed consent, and end-of-life care in ICUs.

Results: A total of 292 ICUs (73% of COVID ICUs) from 18 countries were included in the final analysis. Most (92%) of ICUs restricted their visiting hours, and nearly one-third (32.3%) followed a “no-visitor” policy. There was a significant change in the daily visiting duration in COVID ICUs compared to the pre-pandemic times (p = 0.011). There was also a significant change (p <0.001) in the process of informed consent and end-of-life discussions during the ongoing pandemic compared to pre-pandemic times.

Conclusion: Visiting and communication policies of the ICUs had significantly changed during the COVID-19 pandemic. Future studies are needed to understand the sociopsychological and medicolegal implications of revised policies.

Supplementary Files:
Appendix 1 Survey
Supplement 2 CROSS

Background: The acute physiology and chronic health evaluation (APACHE) II severity score has shown a good calibration and discriminatory value across a range of disease processes and remains the most widely used source of prognostic information on the risk for death in patients admitted to intensive care units (ICUs). Objectives: To study APACHE II scores in patients of acute kidney injury (AKI) admitted in the ICU and to find its association with outcome. Materials and methods: One hundred patients with AKI aged 18 years or above were admitted in the ICU, department of general medicine, of a tertiary care institute in Haryana, North India, from October 2019 to September 2020, were studied. Patients who had known causes of chronic kidney disease (CKD), on maintenance hemodialysis, and those who underwent renal replacement therapy (RRT) or nephrectomy were excluded. All required investigations were performed, and data were collected. The patients were followed till discharge or in-hospital mortality. Results: The mean age of the patients was 55.92 ± 18.18 years. Male–female ratio was 1.5:1. Thirty-five percent of the admitted patients had an in-hospital mortality. Sepsis (47%) was the most common cause of AKI, and 83% of the patients had underlying comorbid conditions. The mean APACHE II score of the expired patients on admission, i.e., 24.80 ± 13.65, was found to be significantly higher compared to the mean APACHE II score (17.25 ± 10.12) of the discharged patients (p-value <0.001). APACHE II score was found to have 57.14% sensitivity, 86.15% specificity, 69% PPV, 78.9% NPV, and 76% diagnostic accuracy to predict mortality among the AKI patients. Conclusion: APACHE II scoring system has a good discrimination and calibration when applied to ICU-admitted AKI patients and is a good predictor of prognosis in them.

Background and aims: We compared the effectiveness of non-invasive ventilation (NIV) provided by helmet mask vs face mask in patients with COVID-19. Methods and materials: Between March and May 2021, a single-center, prospective, open-label randomized controlled research was undertaken. Sixty patients were randomly assigned to one of two groups based on the NIV delivery interface. In group I (n = 30) helmet mask was used and in group II (n = 30) face mask was used for delivery of NIV. The proportion of patients in each group who required endotracheal intubation was the primary outcome. The duration of NIV, length of stay in the intensive care unit (ICU), hospital mortality, ratio of partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂), respiratory rate, patient comfort, and complications were all documented as secondary outcomes. Results: In both groups, demographics, clinical characteristics, and treatment received were comparable. Around 10% of patients in the helmet mask group were intubated, while 43.3% of patients in the face mask group were intubated (p = 0.004). The two groups demonstrated similar hemodynamic patterns. The use of a helmet mask, on the other hand, resulted in enhanced oxygenation (263.57 ± 31.562 vs 209.33 ± 20.531, p = 0.00), higher patient satisfaction (p = 0.001), a lower risk of complications, and a shorter NIV and ICU stay (p = 0.001) (4.53 ± 0.776 vs 7.60 ± 1.354, p = 0.00 and 6.37 ± 0.556 vs 11.57 ± 2.161, p = 0.00). Conclusion: Helmet mask could be a reliable interface for delivery of NIV in COVID-19 and results in a lower rate of endotracheal intubation, better oxygenation with greater patient comfort and shorter ICU stay as compared to face mask used for NIV.

Background: Technological advances in critical care contribute to patient survival, but healthcare professionals working in these units, which require technical expertise, experience highly challenging ethical decision-making processes. Aim: The aim of this study is to determine the attitudes of intensive care nurses toward ethical problems they face during clinical practice and the affecting factors. Method: The study included a total of 294 nurses working in the intensive care units at a city hospital. Data was collected using the Personal Information Form and Ethical Attitude Scale for Nursing Care. Findings: About 58.8% of the participants were females and 71.1% had undergraduate degrees. The total scale score was 56.48 ± 15.98. A statistically significant difference was found between participants’ gender, weekly working hours, ethical definition status, and scale score averages. Conclusion: More than half experienced frequent ethical problems and tried to solve them on their own. Trainings aimed at developing ethical sensitivity and participation in symposiums/conferences that address ethical issues specific to intensive care are recommended.

Background: Microcirculatory derangement is the primary cause of organ dysfunction in patients with sepsis. Assessment of the microcirculation is usually done by means of indirect parameters (SvO₂, transcutaneous PO₂, serum lactate). The aim of our study is to understand microcirculatory abnormalities in patients with sepsis by directly visualizing the tiny vessels using hand-held video microscopes (HVMs) and determining the role of this modality in the prediction of sepsis-related mortality. Methods: A longitudinal prospective hospital-based study was carried out in medical ward and ICU of a tertiary care hospital. Patients admitted with the presumed infectious disease were included. Evaluation of sublingual microcirculation was done in these patients from Day 1 to Day 5. Clinical and laboratory variables and microcirculation variables were compared between patients with or without sepsis and between survivors and non-survivors of sepsis. Chi-square test for categorical and Student's t-test or Wilcoxon rank-sum test for continuous variables were applied. Univariate and multivariate regression analyses were performed using the Cox-proportional hazard model. Results and discussion: On admission, microcirculation assessment measure, PPV (small), was significantly reduced in those with sepsis, as compared to those without sepsis. Multivariable models indicate the inverse relationship of PPV small with mortality.

Background: Maintaining homeostasis is an integral part of all physiological processes both in health and disease including critically ill patients and may impact clinical outcomes. The present study was designed to assess prevalence of serum calcium, phosphate, vitamin-D3, FGF-23, and PTH levels abnormalities in AKI. Patients and methods: Single-center, prospective, observational study in a tertiary care hospital. Patients meeting KDIGO criteria for AKI were included. Paired blood samples were drawn from eligible patients—first sample within 24 hours of AKI diagnosis and second after 5 days or at time of hospital discharge, whichever was earlier for measuring serum calcium (albumin corrected), phosphate, PTH, 25(OH)Vit-D, and FGF-23 levels. Clinical outcomes analyzed included survival status, utilization of RRT, and hospital stay. Results: Of the 50 patients with AKI, about three-fourths were males. Mean age of the participants was 57.32 ± 11.47 years. Around half of patients had hypocalcemia and four-fifths had low serum phosphate. Nearly 82% had low 25(OH)Vit-D and 52% cases had high PTH level. Patients who underwent RRT had numerically higher but not significant serum calcium and PTH levels. FGF-23 levels (pg/mL) were significantly higher in patients on RRT (81.70 ± 17.30 vs non-RRT, 72.43 ± 20.27, p = 0.049), nonsurvivors (87.96 ± 18.82 vs survivors 57.11 ± 15.19, p = 0.045), and those hospitalized for time of stay above median (109.67 ± 26.97 vs below median 70.27 ± 20.43, p = 0.046). Among all the bone and mineral parameters analyzed high FGF23 levels were consistently linked with poor clinical outcomes in AKI. Conclusion: The present study found high prevalence of calcium and phosphate disorders in AKI with dysregulated phosphate homeostasis as evidenced from elevated FGF-23 levels linked with morbidity and mortality in AKI.

Introduction: The expiratory muscles are an indispensable component of respiratory function in critically ill patients, yet is often overlooked. We evaluated the association of abdominal expiratory muscles thickness pattern with weaning. Materials and methods: This was a single-center, prospective observational study done on 81 adult mechanically ventilated patients who underwent the weaning process. Results: Sixteen patients had simple weaning and 65 patients had either difficult or prolonged weaning. The mean and standard deviation (SD) of the thickness of expiratory abdominal muscles—rectus abdominis (RA), internal oblique (IO), external oblique (EO), and transversus abdominis (TA) were significantly more in patients with simple weaning than those with difficult or prolonged weaning. The receiver operating curve (ROC) of expiratory muscles showed RA, IO, EO, TA cut-offs 0.638, 0.492, 0.315, and 0.253 cm, respectively, to predict simple weaning. The pattern of expiratory muscle thickness RA > IO > EO > TA was maintained in both simple and difficult/prolonged weaning groups (p = 0.362). The ROC of diaphragmatic excursion (DE) for predicting simple weaning had cut-off 1.79 cm. The lung ultrasound score (LUS) was 5.75 ± 3.32 in the simple weaning group, compared to 9.71 ± 5.18 in the difficult/prolonged weaning group (p = 0.005). Conclusion: Abdominal expiratory muscles were significantly thicker in patients with simple weaning compared to those with difficult or prolonged weaning. The pattern of expiratory muscle thickness followed the pattern of RA > IO > EO > TA in both simple weaning and difficult or prolonged weaning groups. DE >1.79 cm predicted simple weaning and LUS was significantly lesser in patients with simple weaning (CTRI/2020/11/028895).

Background: Impaired physical activity and functional ability is a significant problem in critical illness survivors. Measurement of physical functioning through intensive care unit (ICU) stay determines patients at risk of poor physical outcomes, monitors efficacy of intervention, and informs recovery trajectories. Objectives: Study objective was to assess physical function trajectory and identify residual functional limitations in critically ill patients admitted to ICU at the point of discharge from the hospital using robust clinical measures. Materials and methods: Following ethical approval, 100 patients (78 males and 22 females) admitted to medical and surgical ICUs were recruited. Scores on Functional Status Score in ICU (FSS-ICU), Physical Function ICU Test (PFIT), and Functional Independence Measure (FIM) were recorded. Day of physiotherapy reference in the ICU was considered as day of ICU admission. Data were collected at three points, namely ICU admission, ICU discharge, and hospital discharge. Results: Scores on all outcome measures increased linearly, and an upward functional trajectory was observed in patients from the point of ICU admission till hospital discharge (p >0.001). Conclusion: Deficits in functional recovery exist until hospital discharge, substantiating the need to implement home-based rehabilitation to recover optimum physical function and independence in activities of daily living.

Background: Patients with acute respiratory distress syndrome (ARDS) are generally ventilated in either 45° head elevation or prone position as they are associated with decreased incidence of ventilator-associated pneumonia and mortality, respectively.^1,2 But in patients with poor lung compliance and super-added diaphragmatic weakness/dysfunction, generating a minimum amount of adequate tidal volume (TV) would be very difficult in propped up/supine/prone position, leading to worsening hypoxia and CO₂ retention. We noticed a sustained increase in TV for patients with poor lung compliance (Cs <15 mL/cm H₂O) and diaphragmatic dysfunction (bilateral diaphragmatic excursion <1 cm, on spontaneous breaths) when the patients are switched to Trendelenburg position with the same ventilator settings. Patients and methods: A case report with possible explanation for the observed changes has been mentioned. Results: Trendelenburg ventilation delivered more TV than propped up or prone ventilation in patients of ARDS with poor lung compliance and diaphragmatic dysfunction. Conclusion: Trendelenburg ventilation increases static lung compliance and delivers more TV when compared to propped up/supine/prone ventilation in patients of ARDS with poor lung compliance and diaphragmatic dysfunction. Although the exact mechanism behind this is not known till now, we formulated few theories that could explain the possible mechanism.

Background: Availability of cardiopulmonary resuscitation (CPR) data from India is limited in published literature and data on patients with renal disease even more so. Documented survival-to-discharge rates worldwide range from 8 to 15% in renal disease as compared to 25% in the general population. Methods: An institution-wide format for collection of cardiac arrest data was introduced in late 2015. We have analyzed all adult onsite cardiac arrests from January 2016 to December 2019. Patient characteristics and CPR parameters were both studied in detail. Primary endpoint was defined as survival to discharge. Association between patient and treatment characteristics and survival to discharge was studied. Results: Successful CPR resulting in patient discharge occurred in 28 (31.4%) out of 89 patients. A very strong association was found between mortality and prolonged CPR (p <0.00001). Events occurring out of hours (p = 0.0029), patients admitted in the intensive care unit (ICU) (p = 0.03), initiated on inotropes (p = 0.003), and patients already on a ventilator (p = 0.0018) had poorer outcomes. Sepsis as the etiology emerged as the most significant association with mortality (p = 0.0007). Patient characteristics such as age, sex, presence or absence of chronic kidney disease, type of dialysis treatment, and vintage were found to be insignificant. Conclusion: Analysis revealed survival to discharge of 31.4%. Sepsis in association with renal disease has been found to be consistent with higher risk for mortality. Other factors such as an out of hours event, admission to ICU, early intubation and inotrope initiation were associated with worse outcomes.

Introduction: Providing cardiopulmonary resuscitation (CPR) to a coronavirus disease-2019 (COVID-19) patient is challenging for the healthcare providers (HCP). COVID-19 cases have specific CPR requirements, which differ from standard resuscitation efforts. Objective: This paper aims to evaluate whether online learning can be an effective methodology for imparting information on the management of cardiopulmonary arrest in COVID-19 patients due to a novel virus unknown to HCP based on evaluation of knowledge acquisition and satisfaction of the nurses in the new area of medicine and virology. Methodology: In a single-arm, one group before and after design, from a cohort of 160 nurses trained in comprehensive cardiac life support (CCLS) formulated by the Indian Resuscitation Council (IRC), 73 nurses participated in the study. After obtaining informed consent through the email from the nurses, baseline data including demographic profile and knowledge related to CPR in COVID-19 patients were collected. An online intervention spread over 1 week was given using a validated e-learning module. The online intervention was found to be effective (pre- and post-intervention knowledge score 13.65 ± 3.01 vs 19.92 ± 1.94, p = 0.001). The majority of nurses were highly satisfied with the content and the training methodology (37.23 ± 4.70). Conclusion: A well-structured, online study material can be used in imparting knowledge and demonstrating the basic and essential skills to nurses, required for giving CPR to COVID-19 patients.

Background: Acute respiratory distress syndrome (ARDS) associated with COVID-19 in children is not well described in the literature, so this study was designed to assess the severity, clinical course, different treatment measures, and outcome of this group of patients. Patients and methods: This descriptive study was performed by retrospective chart review of children admitted in pediatric intensive care unit (PICU) in the age-group of 1 month to 12 years over the period of 6 months (July–December 2020) in a tertiary care pediatric COVID facility in eastern India. Severity of ARDS, ventilator settings, oxygenation and laboratory parameters, and outcomes were documented. Predictors associated with severe ARDS were evaluated. Results: Among 128 laboratory-confirmed pediatric COVID-19 cases admitted in PICU, 18 (14%) developed ARDS, 6 (33.3%) had severe ARDS, and 3 (16.6%) succumbed to death. Outcome was measured by median hospital stay [20 days (IQR 19, 21)], PICU stay [13 days (IQR 10, 16)], and 28-day ventilator-free days [14 days (IQR 13, 22)]. Half (n = 9) of our study cohort had different comorbidities and congenital heart disease being the most common (4, 22.2%). Median positive end-expiratory pressure requirement was 10 cm H₂O (9, 11) for invasively ventilated children (n = 13, 72.2%) along with peak inspiratory pressure of 24 cm H₂O (20, 29) and mean airway pressure of 17 cm H₂O (14, 20). Median oxygenation index was 13.3 (10.5, 18.6). Nine (69.2%) out of 13 intubated children had undergone prone ventilation. C-reactive protein (CRP) and D-dimer levels were significantly high in children with severe ARDS alongside pSOFA and lung USG score. Conclusion: Incidence of ARDS in pediatric COVID-19 though less but is not rare. Elevated CRP, D-dimer values, and high lung USG scores were associated with severe ARDS. Those who died had significant comorbidity.

Objectives: Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Because of the wide usage of antibiotics, acute changes in diet, and the stress of illness, critically ill patients’ homeostasis of the gut microbiome can be disrupted during intensive care unit (ICU) confinement; probiotics are suggested as a beneficial intervention in critically ill patients. We tried to give an overview of the effects of probiotic supplements in critically ill patients based on published systematic reviews (SRs) and meta-analyses (MAs). Data sources: A systematic search was performed in four databases as well as hand searching. Study selection: The results were independently screened in two title/abstracts and full-text stages. Data extraction: Any reported outcomes in each study were extracted, using a data extraction table. Data synthesis: A wide range of outcomes of using probiotic supplements in critically ill patients have been reported in 20 included studies. Based on the current knowledge, we can say that probiotics may reduce the rate of ventilator-associated pneumonia, nosocomial pneumonia, the overall infection rate, duration of mechanical ventilation, and antibiotic use in critically ill patients, but there is not a significant association between using the probiotics and mortality, length of hospitalization, and incidence of diarrhea. Conclusion: Despite the various beneficial effects of probiotics in critically ill patients, there is not yet much evidence supporting the routine use of these supplements and further well-designed multicenter trials are needed to provide “evidence-based” recommendations.

Background: Coronavirus disease-2019 (COVID-2019) pandemic continues to be a significant public health problem. Severe COVID-19 cases have a poor prognosis and extremely high mortality. Prognostic factor evidence can help healthcare providers understand the likely prognosis and identify subgroups likely to develop severe disease with increased mortality risk so that timely treatments can be initiated. This meta-analysis has been performed to evaluate the neutrophil-to-lymphocyte ratio (NLR) at admission as a prognostic factor to predict severe coronavirus disease and mortality. Materials and methods: A literature search was conducted through April 30, 2021, to retrieve all published studies, including gray literature and preprints, investigating the association between NLR and severity or mortality in COVID-19 patients. Screening of studies and data extraction have been done by two authors independently. The methodological quality of the included studies was assessed by the Quality in Prognosis Studies (QUIPS) tool. Results: Twenty-four studies involving 4,080 patients reported the prognostic value of NLR for severe COVID-19. The pooled sensitivity (SEN), specificity (SPE), and area under the curve were 0.75 (95% CI 0.69–0.80), 0.74 (95% CI 0.70–0.78), and 0.81 (95% CI 0.77–0.84). Fifteen studies involving 4,071 patients reported the prognostic value of NLR for mortality in COVID-19. The pooled sensitivity (SEN), specificity (SPE), and area under curve were 0.80 (95% CI 0.72–0.86), 0.78 (95% CI 0.69–0.85), and 0.86 (95% CI 0.83–0.89). Conclusion: The prognostic value of NLR at admission for severity and mortality in patients with COVID-19 is good. Evaluating the NLR at admission can assist treating clinicians to identify early the cases likely to worsen. This would help to conduct early triage, identify potentially high-risk cases, and start optimal monitoring and management, thus reducing the overall mortality of COVID-19. Trial registry: This meta-analysis was prospectively registered on PROSPERO database (Registration Number: CRD42021247801).

Coronavirus disease-2019 (COVID-19) pandemic is raging all over the world. As we are delving more into management of COVID-19, certain new challenges are emerging. One of these is emergence or reactivation of viral infections belonging to Herpesviridae family, especially cytomegalovirus (CMV). Although we have come across the threat of fungal and resistant bacterial infections, experience regarding reactivation or coinfection with concomitant viral infections like CMV during the COVID pandemic is still limited. Whether CMV is a bystander or pathogen is difficult to say categorically and needs further research. In this case series, we intend to describe three patients of COVID-19 with CMV coinfections. To our knowledge, this is the first case series from India.

The pyogenic liver abscess is usually polymicrobial and is seen as a complication of biliary disease or peritonitis. Over the past three decades, monomicrobial liver abscess caused by Klebsiella pneumoniae is being increasingly reported from South East Asian countries like Taiwan and Korea. It is a community-acquired infection caused by a distinct strain, hypervirulent K. pneumoniae, different from classical strain related to the healthcare-associated Klebsiella infections. Diabetes mellitus is a significant risk factor. Reports of the disseminated infection due to hypervirulent Klebsiella are very few in Indian literature. We report the successful management of a diabetic patient with emphysematous liver abscess, brain abscess, and meningitis caused by hypervirulent K. pneumoniae infection.

Central venous catheterization interventions are used in various clinics for diagnostic and treatment purposes. Establishing vascular access is a difficult and critical step, especially in critically ill pediatric patients. Complications include ventricular arrhythmia, air embolism, carotid artery puncture, cardiac tamponade, pneumothorax, hemothorax, artery-vein laceration, thoracic duct injury, and catheter malposition can be observed in patients after central venous catheterization interventions. In this case report, a pediatric case was discussed, in which a central venous catheter was inserted without the usage of imaging methods and without confirming the location and was used, even though no blood return was obtained. It was aimed to draw attention to subdural effusions and spinal canal interventions, which is a rare complication of central venous catheterization interventions.

We report a case of fulminant hepatic failure due to the Budd–Chiari syndrome following preservation with a tropical fever. A young lady came with fever, altered mental status, jaundice, and renal failure. Following tropical workup, it was diagnosed as a case of leptospirosis (WHO Faine's criteria) with multi-organ dysfunction. Despite adequate antimicrobial cover, she progressed to hepatic coma (hyperammonemia) and was noted to have worsening conjugated hyperbilirubinemia. Following history review and evaluation for other causes of hepatic failure, hepatic vein thrombosis was detected in addition to the presence of antibodies against Leptospira antigen. Further studies into the causes of thrombosis and persistent hemoconcentration despite aggressive fluid resuscitation led to the diagnosis of polycythemia vera (cytometric analysis). During her stay, she further worsened despite aggressive organ support including dialysis but she succumbed to gram-negative sepsis that occurred during her stay in ICU. This is an interesting and rare case of leptospirosis that unveiled a case of previously asymptomatic polycythemia vera.

Acute intermittent porphyria (AIP) is autosomal dominant metabolic disorder of adulthood with limited case reports in children. Literature review from Western countries shows that most children present with non-specific gastrointestinal and neuropsychiatric symptoms with no family history. Moreover, the attacks are recurrent and precipitated by various factors (drugs/infection). We describe the case of 11-year-old male child who presented with acute abdominal pain, seizures, hypertension, quadriparesis, neuropathy, and respiratory weakness necessitating ventilatory and intensive care. Diagnosis of AIP was suspected on basis of bedside urine testing and confirmed with hydroxymethylbilane synthase gene mutation study. Besides supportive therapy, child was managed successfully with intravenous hemin, an orphan drug, which was procured with great difficulty. This case is presented for highlighting the diagnostic and therapeutic challenges faced in management of such cases in a developing country. We also review Indian literature for similar cases and discuss the clinical presentation, diagnosis, and management of AIP in children.

Secondary infections in coronavirus disease (COVID) are becoming common. We report a case of a female known case of diabetes, sarcoidosis on steroids and methotrexate admitted with COVID pneumonia. She was treated with steroids, remdesivir, and anticoagulants and was discharged. She revisited the hospital after 2 months with complaints of severe right-sided headache, eye pain, and vomiting. Magentic resonance image of brain and paranasal sinus revealed possibility of invasive rhinosinus mucormycosis. Functional endoscopic sinus surgery (FESS) was done and culture showed growth of mucor and methicillin resistant staphylococcus aureus (MRSA) following which she was started on amphotericin B and antibiotics. She also developed methotrexate and amphotericin B-induced pancytopenia for which injection folinic acid, granulocyte-colony stimulating factor (G-CSF), and erythropoietin were given and was switched over to liposomal amphotericin B. After 5 days of ventilatory support, she was discharged in a stable condition. Extensive steroids in an immunocompromised patient might have led to this event hence physicians should always keep this possibility of secondary fungal infection in COVID patients for understanding the impact of disease.

Platypnea-orthdeoxia syndrome (POS) is a clinical scenario where patient get breathless while sitting or standing. Its important causes are cardiac shunts, hepatopulmonary syndrome and pulmonary ventilation perfusion mismatch. During this pandemic as cases of pulmonary fibrosis increased, we find POS as one of the important cause of morbidity during recovery. Early recognition of this will decrease the morbidity and unrealistic expectation of fast recovery.

We think correlation of Doppler ultrasound derived CA-VTI and echocardiography derived SV needs further exploration in a larger sample and in various models of hypovolemia and shock under ideal measurement conditions before concluding whether carotid artery can be considered a true window to the left ventricle.