[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-458844-105":3,"detail-sidebar-cat-0-en-105":81,"doc-detail-458844-en":131},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":74,"head_meta":76,"extra_data":78,"updated_unix":80},105,"en","cardiac-arrest-secondary-to-hypercapnia-in-an-obese-patient-a-case-of-unresponsiveness-with-preserved-awareness","Cardiac Arrest Secondary to Hypercapnia in an Obese Patient - A Case of Unresponsiveness With Preserved Awareness","","Hypercapnia can precipitate life-threatening cardiac events, especially in patients with obesity hypoventilation syndrome and obstructive sleep apnea, yet preserved awareness during unresponsiveness is rare. The case describes a 58-year-old Caucasian woman with BMI 37.4 kg/m², OSA, and recurrent syncope who developed bradycardia after nitroglycerin, progressed to ventricular tachycardia requiring defibrillation, and reported hearing staff and feeling shocks despite unresponsiveness. Cardiac evaluation found no acute coronary pathology, and she later improved with bilevel/CPAP and weight counseling.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/healthcare/","Healthcare",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/cardiac-arrest-secondary-to-hypercapnia-in-an-obese-patient-a-case-of-unresponsiveness-with-preserved-awareness/458844/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/cardiac-arrest-secondary-to-hypercapnia-in-an-obese-patient-a-case-of-unresponsiveness-with-preserved-awareness/458844.png","ImageObject",300,407,{"name":42,"@type":43},"Muffet","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-30","2026-09-30",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",12,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"Why can hypercapnia lead to dangerous cardiac events in obese patients?","Question",{"text":63,"@type":64},"In obesity hypoventilation syndrome and obstructive sleep apnea, elevated PaCO₂ can produce cardiovascular effects such as pulmonary vascular resistance, right ventricular strain, autonomic dysregulation, and arrhythmogenesis, creating a milieu for ventricular tachyarrhythmias and cardiac arrest.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"What unusual clinical feature occurred during resuscitation in this case?",{"text":68,"@type":64},"Despite apparent unresponsiveness, the patient reported preserved awareness—hearing staff and feeling defibrillation shocks—highlighting that perceptual awareness may persist while motor responsiveness is lost.",{"name":70,"@type":61,"acceptedAnswer":71},"How was the patient evaluated and treated after the cardiac arrest?",{"text":72,"@type":64},"A comprehensive cardiac workup including catheterization, ECG, imaging, echocardiography, Doppler studies, cultures, and laboratory testing found no acute coronary pathology; she received ICU care, implantable cardioverter-defibrillator placement, and later bilevel/CPAP therapy for significant hypercapnia with OSA, along with weight management counseling.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},458844,1791075483,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,106,110,115,120,123,127],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":97,"doc_module":4,"doc_module_name":25,"category_name":98,"show_sort_weight":99,"slug":100},5,"Comic",60,"comic",{"id":102,"doc_module":4,"doc_module_name":25,"category_name":103,"show_sort_weight":104,"slug":105},6,"Technology",50,"technology",{"id":107,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":108,"slug":109},7,40,"healthcare",{"id":111,"doc_module":4,"doc_module_name":25,"category_name":112,"show_sort_weight":113,"slug":114},8,"Research & Report",30,"research-report",{"id":116,"doc_module":4,"doc_module_name":25,"category_name":117,"show_sort_weight":118,"slug":119},9,"Religion & Spirituality",20,"religion-spirituality",{"id":118,"doc_module":4,"doc_module_name":25,"category_name":121,"show_sort_weight":118,"slug":122},"World Cup","world-cup",{"id":124,"doc_module":4,"doc_module_name":25,"category_name":125,"show_sort_weight":124,"slug":126},10,"Lifestyle","lifestyle",{"id":128,"doc_module":4,"doc_module_name":25,"category_name":129,"show_sort_weight":97,"slug":130},19,"General","general",{"code":4,"msg":82,"data":132},{"doc_id":79,"user_id":133,"nickname":42,"user_avatar":134,"doc_module":4,"category_id":107,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":135,"file_id":136,"file_url":137,"file_type":138,"file_size":139,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":111,"language":140,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":12,"update_tm":144,"read_time":118,"preview_page_count":4},962090768927,"https://ap-avatar.wpscdn.com/davatar_085a072bc5b1113ac321206ff7593b45","Review began 11/05/2025  \nReview ended 12/05/2025  \nPublished 12/09/2025  \n© Copyright 2025  \nShah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited.  \nDOI: 10.7759/cureus.98800  \nOpen Access Case Report  \nCardiac Arrest Secondary to Hypercapnia in an Obese Patient: A Case ofUnresponsiveness With Preserved Awareness  \nKajal S. Shah 1 , Ibtesam A. Bhatti 1 , Hinzilah S. Minhas 1 , Sunho Judy Lee 1 , Hassan Jafary 2  \n1. Internal Medicine, Avalon University School of Medicine, Willemstad, CUW 2. Medicine, Stanaford Medical Clinic, Beckley, USA  \nCorresponding author: Hinzilah S. Minhas, [hinzilah.min@gmail.com](hinzilah.min@gmail.com)  \nAbstract  \nIn rare circumstances, hypercapnia can precipitate life-threatening cardiac events, particularly in patients with obesity hypoventilation syndrome and obstructive sleep apnea (OSA) . Awareness during such episodes of unresponsiveness is uncommon, underscoring the complex interaction between respiratory and neurologic physiology. A 58-year-old Caucasian female with a body mass index of 37.4 kg/m², OSA, and a history of recurrent syncope presented to the emergency room with chest pain and shortness of breath. During hospitalization, she received sublingual nitroglycerin, after which she developed bradycardia and was administered atropine. She subsequently progressed into ventricular tachycardia and required two defibrillations to restore sinus rhythm. Remarkably, during resuscitation, she reported awareness despite unresponsiveness, hearing staff, and feeling defibrillation shocks. A comprehensive cardiac evaluation, including catheterization, troponin trends, ECG, imaging, echocardiography, Doppler studies, cultures, and laboratory tests, revealed no acute coronary pathology. She was admitted to the intensive care unit, underwent implantable cardioverter-defibrillator (ICD) placement, and was later discharged. Several days after discharge, she experienced another syncopal episode at home, this time with complete unresponsiveness and no awareness. On readmission, arterial blood gas analysis revealed significant hypercapnia, prompting initiation ofbilevel positive airway pressure therapy. She improved clinically and was discharged on continuous positive airway pressure therapy for OSA, along with weight management counseling. This case emphasizes the importance of recognizing hypercapnia-induced cardiac events in obese patients with severe OSA. Identifying this mechanism, particularly when presenting asunresponsiveness with preserved awareness, highlights the diagnostic challenges and the necessity for vigilant monitoring, non-invasive ventilation, ICD support, and lifestyle modification to prevent recurrence and improve long-term outcomes.  \nCategories: Cardiology, Internal Medicine, Pulmonology  \nKeywords: acute non-st-elevation myocardial infarction, acute respiratory failure, cardiac arrest, hypercapnia, obesity hypoventilation syndrome, obstructive sleep apnea, pneumonia, syncope, unresponsiveness, ventricular fibrillation  \nIntroduction  \nObesity hypoventilation syndrome (OHS) is defined by the triad of obesity (body mass index (BMI) ≥30  \nkg/m²), chronic daytime hypercapnia (PaCO₂ >45 mmHg), and sleep-disordered breathing, most commonly obstructive sleep apnea (OSA) [1,2] . Excess adiposity imposes mechanical loads on the chest wall and blunts central ventilatory drive, predisposing patients to chronic carbon dioxide retention and recurrent episodes of acute-on-chronic hypercapnic respiratory failure [3] .  \nAlthough hypercapnia is typically viewed as a marker of respiratory insufficiency, emerging evidence suggests that elevated PaCO₂ can have profound cardiovascular effects, including increased pulmonary vascular resistance, right ventricular strain, autonomic dysregulation, a","cbCaiai65uHH011d","https://ap.wps.com/l/cbCaiai65uHH011d","pdf",4667140,"English","# Abstract\n## Introduction\n## Case Presentation","[{\"question\":\"Why can hypercapnia lead to dangerous cardiac events in obese patients?\",\"answer\":\"In obesity hypoventilation syndrome and obstructive sleep apnea, elevated PaCO₂ can produce cardiovascular effects such as pulmonary vascular resistance, right ventricular strain, autonomic dysregulation, and arrhythmogenesis, creating a milieu for ventricular tachyarrhythmias and cardiac arrest.\"},{\"question\":\"What unusual clinical feature occurred during resuscitation in this case?\",\"answer\":\"Despite apparent unresponsiveness, the patient reported preserved awareness—hearing staff and feeling defibrillation shocks—highlighting that perceptual awareness may persist while motor responsiveness is lost.\"},{\"question\":\"How was the patient evaluated and treated after the cardiac arrest?\",\"answer\":\"A comprehensive cardiac workup including catheterization, ECG, imaging, echocardiography, Doppler studies, cultures, and laboratory testing found no acute coronary pathology; she received ICU care, implantable cardioverter-defibrillator placement, and later bilevel/CPAP therapy for significant hypercapnia with OSA, along with weight management counseling.\"}]","Cardiac Arrest Secondary to Hypercapnia in an Obese Patient - A Case of Unresponsiveness With Preserved Awareness | PDF",1790754588]