Utilization of Shock Team and Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) in the Management of Cardiogenic Shock in Northern Ontario.

Background: Despite advancements in critical care and coronary revascularization, cardiogenic shock (CS) outcomes remain poor. Implementing a shock team and use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) have been associated with improved CS outcomes, but its feasibility in remote and rural areas remains unknown. Methods: This retrospective study included patients with CS who required mechanical circulatory support (MCS) at Health Sciences North, Sudbury, Ontario. The analysis aimed to accomplish 2 objectives: first, to review the outcomes associated with use of Impella (Abiomed, Danvers, MA) and, second, to assess the feasibility of establishing a shock team to facilitate the local implementation of VA-ECMO. The primary endpoint was in-hospital mortality. Results: The outcomes of 15 patients with CS who received Impella between 2015 and 2021 were reviewed. Their average age was 65 years (standard deviation [SD]: 13), and 8 patients (53%) were female. CS was ischemic in 12 patients (80%). Transfemoral Impella CP (cardiac power) was the most frequently used (93%). Thirteen patients (87%) died during the index hospital stay post-Impella because of progressive circulatory failure. The shock team was established following consultations with several Canadian MCS centres, leading to the development of a protocol to guide use of MCS. There have been 4 cases in which percutaneous VA-ECMO using Cardiohelp (Getinge/Maquet, Wayne, NJ) has been used; 3 (75%) survived beyond the index hospitalization. Conclusions: This analysis demonstrated the feasibility of implementing a shock team in remote Northern Ontario, enabling the use of VA-ECMO with success in a centre with a sizeable rural catchment area. This initiative helps address the gap in cardiac care outcomes between rural and urban areas in Ontario.

Introduction: En dépit des avancées des soins aux patients en phase critique et de la revascularisation coronarienne, les résultats du choc cardiogénique (CC) semblent mauvais. La mise en place d'une équipe de choc et l'utilisation de l'oxygénation extracorporelle (ECMO, de l'anglais extracorporeal membrane oxygenation) par voie veino-artérielle (VA) (VA-ECMO) ont été associées à de meilleurs résultats du CC, mais on ignore sa faisabilité dans les régions éloignées et rurales. Méthodes: La présente étude rétrospective portait sur des patients en CC qui ont eu besoin d'une assistance circulatoire mécanique (ACM) à Horizon Santé-Nord, à Sudbury, en Ontario. L'analyse visait 2 objectifs : le premier objectif était de passer en revue les résultats associés à l'utilisation de Impella (Abiomed, Danvers, MA) et, le deuxième était d'évaluer la faisabilité de la mise en place d'une équipe de choc pour faciliter la mise en œuvre locale de la VA-ECMO. Le principal critère d'évaluation était la mortalité intrahospitalière. Résultats: Nous avons passé en revue les résultats cliniques de 15 patients ayant subi un CC qui avaient reçu une Impella entre 2015 et 2021. L'âge moyen était de 65 ans (écart type [ET] : 13), et 8 patients (53 %) étaient des femmes. Le CC était d'origine ischémique chez 12 patients (80 %). L'Impella CP (cardiac power, soit la pompe cardiaque) par voie transfémorale était la plus fréquemment utilisée (93 %). Treize patients (87 %) sont morts durant le séjour de référence à l'hôpital après l'utilisation de l'Impella en raison d'insuffisance circulatoire progressive. La mise en place de l'équipe de choc à la suite des consultations dans plusieurs centres canadiens d'ACM a mené à l'élaboration d'un protocole d'utilisation de l'ACM. Il y a eu 4 cas chez lesquels la VA-ECMO par voie percutanée à l'aide de Cardiohelp (Getinge/Maquet, Wayne, New Jersey, É.-U.) a été utilisée ; 3 (75 %) ont survécu après l'hospitalisation de référence. Conclusions: Cette analyse a démontré la faisabilité de la mise en place d'une équipe de choc dans les régions éloignées du nord de l'Ontario, qui a permis d'utiliser efficacement la VA-ECMO dans un centre d'une circonscription hospitalière rurale non négligeable. Cette initiative aide à remédier à l'écart des résultats en soins cardiaques entre les régions rurales et urbaines de l'Ontario.

Simultaneous venous-arterial Doppler during preload augmentation: illustrating the Doppler Starling curve.

Providing intravenous (IV) fluids to a patient with signs or symptoms of hypoperfusion is common. However, evaluating the IV fluid 'dose-response' curve of the heart is elusive. Two patients were studied in the emergency department with a wireless, wearable Doppler ultrasound system. Change in the common carotid arterial and internal jugular Doppler spectrograms were simultaneously obtained as surrogates of left ventricular stroke volume (SV) and central venous pressure (CVP), respectively. Both patients initially had low CVP jugular venous Doppler spectrograms. With preload augmentation, only one patient had arterial Doppler measures indicative of significant SV augmentation (i.e., 'fluid responsive'). The other patient manifested diminishing arterial response, suggesting depressed SV (i.e., 'fluid unresponsive') with evidence of ventricular asynchrony. In this short communication, we describe how a wireless, wearable Doppler ultrasound simultaneously tracks surrogates of cardiac preload and output within a 'Doppler Starling curve' framework; implications for IV fluid dosing are discussed.

Detecting the Change in Total Circulatory Flow with a Wireless, Wearable Doppler Ultrasound Patch: A Pilot Study.

Measuring fluid responsiveness is important in the management of critically ill patients, with a 10-15% change in cardiac output typically being used to indicate "fluid responsiveness." Ideally, these changes would be measured noninvasively and peripherally. The aim of this study was to determine how the common carotid artery (CCA) maximum velocity changes with total circulatory flow when confounding factors are mitigated and determine a value for CCA maximum velocity corresponding to a 10% change in total circulatory flow. DESIGN: Prospective observational pilot study. SETTING: Patients undergoing elective, on-pump coronary artery bypass grafting (CABG) surgery. PATIENTS: Fourteen patients were referred for elective coronary artery bypass grafting surgery. INTERVENTIONS: Cardiopulmonary bypass (CPB) pump flow changes during surgery, as chosen by the perfusionist. MEASUREMENTS: A hands-free, wearable Doppler patch was used for CCA velocity measurements with the aim of preventing user errors in ultrasound measurements. Maximum CCA velocity was determined from the spectrogram acquired by the Doppler patch. CPB flow rates were recorded as displayed on the CPB console, and further measured from the peristaltic pulsation frequency visible on the recorded Doppler spectrograms. MAIN RESULTS: Changes in CCA maximum velocity tracked well with changes in CPB flow. On average, a 13.6% change in CCA maximum velocity was found to correspond to a 10% change in CPB flow rate. CONCLUSIONS: Changes in CCA velocity may be a useful surrogate for determining fluid responsiveness when user error can be mitigated.

Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge.

A preload challenge (PC) is a clinical maneuver that, first, increases the cardiac filling (i.e., preload) and, second, calculates the change in cardiac output. Fundamentally, a PC is a bedside approach for testing the Frank-Starling-Sarnoff (i.e., "cardiac function") curve. Normally, this curve has a steep slope such that a small change in the cardiac preload generates a large change in the stroke volume (SV) or cardiac output. However, in various disease states, the slope of this relationship flattens such that increasing the volume into the heart leads to little rise in the SV. In this pathological scenario, additional cardiac preload (e.g., intravenous fluid) is unlikely to be physiologically effective and could lead to harm if organ congestion evolves. Therefore, inferring both the cardiac preload and output is clinically useful as it may guide intravenous (IV) fluid resuscitation. Accordingly, the goal of this protocol is to describe a method for contemporaneously tracking the surrogates of cardiac preload and output using a novel, wireless, wearable ultrasound during a well-validated preload challenge.

The Safety of Early Discharge Following Transcatheter Aortic Valve Implantation Among Patients in Northern Ontario and Rural Areas Utilizing the Vancouver 3M TAVI Study Clinical Pathway.

Background: Early hospital ( < 48 hours) discharge following transcatheter aortic valve implantation (TAVI) is an increasingly adopted practice; however, data on the safety of such an approach among patients residing in North Ontario, including remote and medically underserved areas, are lacking. Methods: This retrospective study included patients who underwent TAVI in Sudbury, Ontario. The safety of early discharge after implementation of the Vancouver 3M (multidisciplinary, multimodality, but minimalist) clinical pathway was assessed. The primary endpoint was 30-day mortality. Resource utilization before vs after 3M clinical pathway implementation was also compared. Results: A total of 291 patients who underwent TAVI between 2012 and 2021 were included in the study. One in-hospital death (0.6%) occurred after the 3M clinical pathway implementation, with no mortality observed beyond hospital discharge. Eleven patients (6.7%) required rehospitalization within 30 days. The need for mechanical ventilation and surgical vascular cut-down declined from 100% and 97%, respectively, at baseline, to 6% and 2%. The number of patients receiving TAVI on a given procedural day increased from 2 to 3 patients. The median post-TAVI hospital length of stay decreased from 5 days (2-6 days) to 1 day (1-3 days) after 3M clinical pathway implementation. Conclusions: Following TAVI, early discharge of selected patients residing in Northern Ontario, including rural areas, using the Vancouver 3M clinical pathway was associated with favourable outcomes, short length of stay, and more-efficient resource utilization. These data can help improve healthcare efficiency and bridge variations in TAVI funding and accessibility in underserved locations.

Contexte: Il est de plus en plus admis d'accorder un congé rapide de l'hôpital (< 48 heures) après une implantation valvulaire aortique par cathéter (IVAC); toutefois, on ne dispose pas de données sur l'innocuité de cette pratique pour les patients du nord de l'Ontario, y compris ceux qui résident en régions éloignées moins bien desservies par les services médicaux. Méthodologie: Cette étude rétrospective a porté sur des patients ayant subi une IVAC à Sudbury (Ontario). L'innocuité d'un congé rapide après l'implantation selon le parcours de soins Vancouver 3M (multidisciplinaire, multimodal, mais minimaliste) a été évaluée. Le principal paramètre d'évaluation était la mortalité à 30 jours. Une comparaison de l'utilisation des ressources avant et après la mise en œuvre du parcours de soins 3M a également été effectuée. Résultats: Au total, 291 patients ayant subi une IVAC entre 2012 et 2021 ont été inclus dans l'étude. Un décès à l'hôpital (0,6 %) est survenu après la mise en œuvre du parcours de soins 3M, et aucune mortalité n'a été relevée après le congé de l'hôpital. Onze patients (6,7 %) ont dû être réhospitalisés dans les 30 jours suivants. Le recours à la ventilation mécanique et à la dénudation vasculaire a chuté, passant de 100 % et 97 % au départ, respectivement, à 6 % et 2 %. Le nombre de patients par jour d'intervention subissant une IVAC est passé de deux à trois patients. À la suite de la mise en œuvre du parcours de soins 3M, la durée médiane du séjour à l'hôpital après une IVAC est passée de cinq jours (deux à six jours) à un jour (un à trois jours). Conclusions: Après une IVAC, le congé rapide de patients sélectionnés habitant dans le nord de l'Ontario, y compris ceux habitant en région rurale, selon le parcours de soins Vancouver 3M a été associé à des résultats de santé favorables, à une durée courte d'hospitalisation et à une utilisation plus efficace des ressources. Ces données peuvent contribuer à améliorer l'efficacité des soins de santé et à combler des écarts liés aux variations du financement et de l'accessibilité des IVAC dans les régions moins bien desservies.

A Wireless Wearable Doppler Ultrasound Detects Changing Stroke Volume: Proof-of-Principle Comparison with Trans-Esophageal Echocardiography during Coronary Bypass Surgery.

BACKGROUND: A novel, wireless, ultrasound biosensor that adheres to the neck and measures real-time Doppler of the carotid artery may be a useful functional hemodynamic monitor. A unique experimental set-up during elective coronary artery bypass surgery is described as a means to compare the wearable Doppler to trans-esophageal echocardiography (TEE). METHODS: A total of two representative patients were studied at baseline and during Trendelenburg position. Carotid Doppler spectra from the wearable ultrasound and TEE were synchronously captured. Areas under the receiver operator curve (AUROC) were performed to assess the accuracy of changing common carotid artery velocity time integral (ccVTI∆) at detecting a clinically significant change in stroke volume (SV∆). RESULTS: Synchronously measuring and comparing Doppler spectra from the wearable ultrasound and TEE is feasible during Trendelenburg positioning. In two representative cardiac surgical patients, the ccVTI∆ accurately detected a clinically significant SV∆ with AUROCs of 0.89, 0.91, and 0.95 when single-beat, 3-consecutive beat and 10-consecutive beat averages were assessed, respectively. CONCLUSION: In this proof-of-principle research communication, a wearable Doppler ultrasound system is successfully compared to TEE. Preliminary data suggests that the diagnostic accuracy of carotid Doppler ultrasonography at detecting clinically significant SV∆ is enhanced by averaging more cardiac cycles.

Diagnosing and understanding the mechanisms behind orthodeoxia syndrome.

Orthodeoxia is a rare clinical syndrome characterized by deoxygenation in the upright position and relieved by recumbency. Our rounds illustrate how cardiovascular imaging and echocardiography can be used to diagnose the etiology of this syndrome with respect to its association with patent foramen ovale (PFO) and ascending aortic aneurysms. The rounds also demonstrate the use of peri-operative transesophageal echocardiography (TEE) in understanding the mechanisms contributing to the condition and aid in appropriately planning medical and surgical management.

The influence of duration of fluid abstinence on hypotension during propofol induction.

BACKGROUND: Prolonged preoperative fasting might be expected to exacerbate hypotension during the induction of general anesthesia. We aimed to establish whether the duration of preoperative abstinence from fluids independently contributed to arterial blood pressure changes and dosage requirements during propofol induction. METHODS: We prospectively recruited 130 ASA I or II nonhypertensive patients, ages 18 to 65 years scheduled for surgery under general anesthesia. Standard physiological and electroencephalographic bispectral index (BIS) monitoring was applied to each patient. Intravenous propofol infusion was commenced at 40 mg · kg(-1) · h(-1) and reduced to 8 mg · kg(-1) · h(-1) when the BIS decreased to 50. Frequent cardiovascular data were collected for 15 minutes. The primary endpoint was maximal percentage decrease from baseline mean arterial blood pressure (max%ΔMAP). The secondary endpoint was the propofol dose at which BIS decreased to 50 (PDBIS50). Univariate linear regression and then multivariate linear regression was used to analyze the associations between potential predictors, including fasting time, and these 2 endpoints. RESULTS: Mean fluid abstinence time was 694 minutes (range: 115 to 1263 minutes). Unstandardized regression coefficients (95% confidence intervals [CIs]) for fluid abstinence (minutes) versus max%ΔMAP (%) and PDBIS50 (mg) were, respectively, 0.003% (-0.002% to + 0.009%) and 0.021 mg (-0.017 mg to + 0.059 mg). On adjusting for other, significant predictors in a multivariate model and applying type II sum of squares tests, the corresponding values were -0.0001% (-0.004% to + 0.004%, P = 0.94) and -0.006 mg (-0.039 mg to + 0.026 mg, P = 0.70). The effect of a 1-hour increase in fluid abstinence on max%ΔMAP was therefore -0.01% (-0.26% to + 0.24%) and on PDBIS50, -0.38 mg (-2.34 mg to + 1.58 mg). CONCLUSION: When propofol is infused rapidly for induction of anesthesia in healthy adults younger than 65 years, the duration of preoperative fluid abstinence does not appear to affect MAP or propofol dose requirements.