Predictors of cardiac arrest in severe accidental hypothermia.

STUDY OBJECTIVE: To indicate predictors of witnessed hypothermic cardiac arrest. METHODS: We conducted a retrospective analysis of 182 patients with severe accidental hypothermia (i.e., with core body temperature of ≤28 °C) who presented with preserved spontaneous circulation at first contact with medical services. We divided the study population into two groups: patients who suffered hypothermic cardiac arrest (HCA) at any time between encounter with medical service and restoration of normothermia, and those who did not sustain HCA. The analyzed outcome was the occurrence of cardiac arrest prior to achieving normothermia. Hemodynamic and biochemical parameters were analyzed with regard to their association with the outcome. RESULTS: Fifty-two (29%) patients suffered HCA. In a univariable analysis, four variables were significantly associated with the outcome, namely heart rate (p < 0.001), systolic blood pressure (p = 0.03), ventricular arrhythmia (p = 0.001), and arterial oxygen partial pressure (p = 0.002). In the multivariable logistic regression the best model predicting HCA included heart rate, PaO2, and Base Excess (AUROC = 0.78). In prehospital settings, when blood gas analysis is not available, other multivariable model including heart rate and occurrence of ventricular arrhythmia (AUROC = 0.74) can be used. In this study population, threshold values of heart rate of 43/min, temperature-corrected PaO2 of 72 mmHg, and uncorrected PaO2 of 109 mmHg, presented satisfactory sensitivity and specificity for HCA prediction. CONCLUSIONS: In patients with severe accidental hypothermia, the occurrence of HCA is associated with a lower heart rate, hypoxemia, ventricular arrhythmia, lower BE, and lower blood pressure. These parameters can be helpful in the early selection of high-risk patients and their allocation to extracorporeal rewarming facilities.

Internal jugular vein collapsibility does not predict fluid responsiveness in spontaneously breathing patients after cardiac surgery.

PURPOSE: The objective of our study was to evaluate the diagnostic accuracy of internal jugular vein (IJV) collapsibility as a predictor of fluid responsiveness in spontaneously breathing patients after cardiac surgery. METHODS: In this prospective observational study, spontaneously breathing patients were enrolled on the first postoperative day after coronary artery bypass grafting. Hemodynamic data coupled with simultaneous ultrasound assessment of the IJV were collected at baseline and after passive leg raising test (PLR). Continuous cardiac index (CI), stroke volume (SV), and stroke volume variation (SVV) were assessed with FloTracTM/EV1000™. Fluid responsiveness was defined as an increase in CI ≥ 10% after PLR. We compared the differences in measured variables between fluid responders and non-responders and tested the ability of ultrasonographic IJV indices to predict fluid responsiveness. RESULTS: Fifty-four patients were included in the study. Seventeen (31.5%) were fluid responders. The responders demonstrated significantly lower inspiratory and expiratory diameters of the IJV at baseline, but IJV collapsibility was comparable (P = 0.7). Using the cut-off point of 20%, IJV collapsibility predicted fluid responsiveness with a sensitivity of 76.5% and specificity of 38.9%, ROC AUC 0.55. CONCLUSION: In spontaneously breathing patients after surgical coronary revascularisation, collapsibility of the internal jugular vein did not predict fluid responsiveness.

Vasopressin in Patients with Septic Shock and Dynamic Left Ventricular Outflow Tract Obstruction.

PURPOSE: Left ventricular outflow tract obstruction (LVOTO) is a relatively uncommon but severe condition that may lead to hemodynamic impairment. It can be elicited by morphological (left ventricular hypertrophy, sigmoid septum, prominent papillary muscle, prolonged anterior mitral valve leaflet) and functional (hypovolemia, low afterload, hypercontractility, catecholamines) factors. We sought to determine the incidence of the most severe form of LVOTO in septic shock patients and describe the therapeutic effects of vasopressin. METHODS: Over a period of 29 months, 527 patients in septic shock were screened for LVOTO. All were mechanically ventilated and treated according to sepsis bundles, including pre-load optimization and norepinephrine infusion. Vasopressin was added in addition to norepinephrine to reduce the adrenergic burden and decrease LVOTO. RESULTS: Ten patients were diagnosed with the most severe form of LVOTO, including systolic anterior mitral valve motion (SAM) and severe mitral regurgitation (MR) with pulmonary oedema. The median norepinephrine dosage to obtain a mean arterial pressure of ≥70 mmHg was 0.58 mcg/Kg/min (IQR 0.40-0.78). All patients had a hyper-contractile left ventricle, septal hypertrophy, significant LVOTO (peak gradient 78 [56-123] mmHg) associated with SAM and severe MR with pulmonary oedema. Vasopressin (median 4 IU/h) allowed a significant reduction of norepinephrine (0.18 [0.14-0.30] mcg/kg/min; p = 0.01), LVOT gradient (35 [24-60] mmHg; p = 0.01) and MR with a significant paO2/FiO2 increase (174 [125-213] mmHg; p = 0.01). CONCLUSION: Vasopressin allowed a reduction of norepinephrine with subsequent LVOTO reduction and hemodynamic improvement of the most severe form of LVOTO, which represented 1.9% of all septic shock patients.

Prognostic thresholds of outcome predictors in severe accidental hypothermia.

Hemodynamically unstable patients with severe hypothermia and preserved circulation should be transported to dedicated extracorporeal life support (ECLS) centers, but not all are eligible for extracorporeal therapy. In this group of patients, the outcome of rewarming may sometimes be unfavorable. It is, therefore, crucial to identify potential risk factors for death. Furthermore, it is unclear what criterion for hemodynamic stability should be adopted for patients with severe hypothermia. The aim of this study is to identify pre-rewarming predictors of death and their threshold values in hypothermic patients with core temperature ≤ 28 °C and preserved circulation, who were treated without extracorporeal rewarming. We conducted a multicenter retrospective study involving patients in accidental hypothermia with core temperature 28 °C or lower, and preserved spontaneous circulation on rewarming initiation. The data were collected from the International Hypothermia Registry, HELP Registry, and additional hospital data. The primary outcome was survival to hospital discharge. We conducted a multivariable logistic regression and receiver operating characteristic curve (ROC) analysis. In the multivariate analysis of laboratory tests and vital signs, systolic blood pressure (SBP) adjusted for cooling circumstances and base excess (BE) were identified as the best predictor of death (OR 0.974 95% CI 0.952-0.996), AUC ROC 0.79 (0.70-0.88). The clinically relevant cutoff for SBP was identified at 90 mmHg with a sensitivity of 0.74 (0.54-0.89) and a specificity of 0.70 (0.60-0.79). The increased risk of death among hypothermic patients with preserved circulation occurs among those with an SBP below 90 mmHg and in those who developed hypothermia in their homes.

The outcomes of patients with septic shock treated with propafenone compared to amiodarone for supraventricular arrhythmias are related to end-systolic left atrial volume.

AIMS: A recently published trial has shown no differences in outcomes between patients with new-onset supraventricular arrhythmia (SVA) in septic shock treated with either propafenone or amiodarone. However, these outcome data have not been evaluated in relation to the presence or absence of a dilated left atrium (LA). METHODS AND RESULTS: Patients with SVA and a left ventricular ejection fraction ≥ 35% were randomized to receive intravenous propafenone (70 mg bolus followed by 400-840 mg/24 h) or amiodarone (300 mg bolus followed by 600-1800 mg/24 h). They were divided into groups based on whether their end-systolic left atrial volume (LAVI) was ≥40 mL/m². The subgroup outcomes assessed were survival at ICU discharge, 1 month, 3 months, 6 months, and 12 months. Propafenone cardioverted earlier (P = 0.009) and with fewer recurrences (P = 0.001) in the patients without LA enlargement (n = 133). Patients with LAVI < 40 mL/m2 demonstrated a mortality benefit of propafenone over the follow-up of 1 year [Cox regression, hazard ratio (HR) 0.6 (95% CI 0.4; 0.9), P = 0.014]. Patients with dilated LA (n = 37) achieved rhythm control earlier in amiodarone (P = 0.05) with similar rates of recurrences (P = 0.5) compared to propafenone. The outcomes for patients with LAVI ≥ 40 mL/m2 were less favourable with propafenone compared to amiodarone at 1 month [HR 3.6 (95% CI 1.03; 12.5), P = 0.045]; however, it did not reach statistical significance at 1 year [HR 1.9 (95% CI 0.8; 4.4), P = 0.138]. CONCLUSION: Patients with non-dilated LA who achieved rhythm control with propafenone in the setting of septic shock had better short-term and long-term outcomes than those treated with amiodarone, which seemed to be more effective in patients with LAVI ≥ 40 mL/m². TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03029169, registered on 24 January 2017.

Prediction of Fluid Responsiveness Using Combined End-Expiratory and End-Inspiratory Occlusion Tests in Cardiac Surgical Patients.

End-expiratory occlusion (EEO) and end-inspiratory occlusion (EIO) tests have been successfully used to predict fluid responsiveness in various settings using calibrated pulse contour analysis and echocardiography. The aim of this study was to test if respiratory occlusion tests predicted fluid responsiveness reliably in cardiac surgical patients with protective ventilation. This single-centre, prospective study, included 57 ventilated patients after elective coronary artery bypass grafting who were indicated for fluid expansion. Baseline echocardiographic measurements were obtained and patients with significant cardiac pathology were excluded. Cardiac index (CI), stroke volume and stroke volume variation were recorded using uncalibrated pulse contour analysis at baseline, after performing EEO and EIO tests and after volume expansion (7 mL/kg of succinylated gelatin). Fluid responsiveness was defined as an increase in cardiac index by 15%. Neither EEO, EIO nor their combination predicted fluid responsiveness reliably in our study. After a combined EEO and EIO, a cut-off point for CI change of 16.7% predicted fluid responsiveness with a sensitivity of 61.8%, specificity of 69.6% and ROC AUC of 0.593. In elective cardiac surgical patients with protective ventilation, respiratory occlusion tests failed to predict fluid responsiveness using uncalibrated pulse contour analysis.

Extracorporeal Rewarming Is Associated With Increased Survival Rate in Severely Hypothermic Patients With Preserved Spontaneous Circulation.

Treatment recommendations for rewarming patients in severe accidental hypothermia with preserved spontaneous circulation have a weak evidence due to the absence of randomized clinical trials. We aimed to compare the outcomes of extracorporeal versus less-invasive rewarming of severely hypothermic patients with preserved spontaneous circulation. We conducted a multicenter retrospective study. The patient population was compiled based on data from the HELP Registry, the International Hypothermia Registry, and a literature review. Adult patients with a core temperature <28°C and preserved spontaneous circulation were included. Patients who underwent extracorporeal rewarming were compared with patients rewarmed with less-invasive methods, using a matched-pair analysis. The study population consisted of 50 patients rewarmed extracorporeally and 85 patients rewarmed with other, less-invasive methods. Variables significantly associated with survival included: lower age; outdoor cooling circumstances; higher blood pressure; higher PaCO 2 ; higher BE; higher HCO 3 ; and the absence of comorbidities. The survival rate was higher in patients rewarmed extracorporeally ( p = 0.049). The relative risk of death was twice as high in patients rewarmed less invasively. Based on our data, we conclude that patients in severe accidental hypothermia with circulatory instability can benefit from extracorporeal rewarming without an increased risk of complications.

Propafenone versus amiodarone for supraventricular arrhythmias in septic shock: a randomised controlled trial.

PURPOSE: Acute onset supraventricular arrhythmias can contribute to haemodynamic compromise in septic shock. Both amiodarone and propafenone are available interventions, but their clinical effects have not yet been directly compared. METHODS: In this two-centre, prospective controlled parallel group double blind trial we recruited 209 septic shock patients with new-onset arrhythmia and a left ventricular ejection fraction above 35%. The patients were randomised in a 1:1 ratio to receive either intravenous propafenone (70 mg bolus followed by 400-840 mg/24 h) or amiodarone (300 mg bolus followed by 600-1800 mg/24 h). The primary outcomes were the proportion of patients who had sinus rhythm 24 h after the start of the infusion, time to restoration of the first sinus rhythm and the proportion of patients with arrhythmia recurrence. RESULTS: Out of 209 randomized patients, 200 (96%) received the study drug. After 24 h, 77 (72.8%) and 71 (67.3%) were in sinus rhythm (p = 0.4), restored after a median of 3.7 h (95% CI 2.3-6.8) and 7.3 h (95% CI 5-11), p = 0.02, with propafenone and amiodarone, respectively. The arrhythmia recurred in 54 (52%) patients treated with propafenone and in 80 (76%) with amiodarone, p < 0.001. Patients with a dilated left atrium had better rhythm control with amiodarone (6.4 h (95% CI 3.5; 14.1) until cardioversion vs 18 h (95% CI 2.8; 24.7) in propafenone, p = 0.05). CONCLUSION: Propafenone does not provide better rhythm control at 24 h yet offers faster cardioversion with fewer arrhythmia recurrences than with amiodarone, especially in patients with a non-dilated left atrium. No differences between propafenone and amiodarone on the prespecified short- and long-term outcomes were observed.

Interpleural location of chest drain on ultrasound excludes pneumothorax and associates with a low degree of chest drain foreshortening on the antero-posterior chest X-ray.

BACKGROUND: The role of chest drain (CD) location by bedside imaging methods in the diagnosis of pneumothorax has not been explored in a prospective study yet. METHODS: Covid-19 ARDS patients with pneumothorax were prospectively monitored with chest ultrasound (CUS) and antero-posterior X-ray (CR) performed after drainage in the safe triangle. CD foreshortening was estimated as a decrease of chest drain index (CDI = length of CD in chest taken from CR/depth of insertion on CD scale + 5 cm). The angle of inclination of the CD was measured between the horizontal line and the CD at the point where it enters pleural space on CR. RESULTS: Of the total 106 pneumothorax cases 80 patients had full lung expansion on CUS, the CD was located by CUS in 69 (86%), the CDI was 0.99 (0.88-1.06). 26 cases had a residual pneumothorax after drainage (24.5%), the CD was located by CUS in 31%, the CDI was 0.76 (0.6-0.93),p < 0.01. The risk ratio for a pneumothorax in a patient with not visible CD between the pleural layers on CUS and an associated low CDI on CR was 5.97, p˂0.0001. For the patients with a steep angle of inclination (> 50°) of the CD, the risk ratio for pneumothorax was not significant (p < 0.17). A continued air leak from the CD after drainage is related to the risk for a residual pneumothorax (RR 2.27, p = 0.003). CONCLUSION: Absence of a CD on CUS post drainage, low CDI on CR and continuous air leak significantly associate with residual occult pneumothorax which may evade diagnosis on an antero-posterior CR.

A Randomized Comparison of Non-Channeled GlidescopeTM Titanium Versus Channeled KingVisionTM Videolaryngoscope for Orotracheal Intubation in Obese Patients with BMI > 35 kg·m-2.

Videolaryngoscopes may improve intubating conditions in obese patients. A total of 110 patients with a body mass index > 35 kg∙m-2 were prospectively randomized to tracheal intubation using non-channeled Glidescope Titanium or channeled King Vision videolaryngoscope. The primary outcome was the time to tracheal intubation. Secondary outcomes included: total success rate, number of attempts, the quality of visualization, peri-procedural and post-proceduralcomplications. Time to the first effective breath was shorter with the King Vision (median; 95% CI)-36; 34-39 s vs. 42; 40-50 in the Glidescope group (p = 0.007). The total success rate was higher in the Glidescope group-100% vs. 89.1% (p = 0.03). There was a higher incidence of moderate and difficult laryngoscopy in the King Vision group. No difference was recorded in first attempt success rates, total number of attempts, use of additional maneuvers, intraoperative trauma, or any significant decrease in SpO2 during intubation. No serious complications were noted and the incidence of postoperative complaints was without difference. Although tracheal intubation with King Vision showed shorter time to the first breath, total success was higher in the Glidescope group, and all but one patients where intubation failed with the KingVision were subsequently intubated with the Glidescope.

Video Laryngoscopic Intubation Using the King VisionTM Laryngoscope in a Simulated Cervical Spine Trauma: A Comparison Between Non-Channeled and Channeled Disposable Blades.

Videolaryngoscopes may reduce cervical spine movement during tracheal intubation in patients with neck trauma. This manikin study aimed to compare the performance of disposable non-channeled and channeled blades of the King Vision™ videolaryngoscope in simulated cervical spine injury. Fifty-eight anesthesiologists in training intubated the TruMan manikin with the neck immobilized using each blade in a randomized order. The primary outcome was the time needed for tracheal intubation, secondary aims included total success rate, the time required for visualization of the larynx, number of attempts, view of the vocal cords, and subjective assessment of both methods. Intubation time with the channeled blade was shorter, with a median time of 13 s (IQR 9-19) vs. 23 s (14.5-37.5), p < 0.001, while times to visualization of the larynx were similar in both groups (p = 0.54). Success rates were similar in both groups, but intubation with the non-channeled blade required more attempts (1.52 vs. 1.05; p < 0.001). The participants scored the intubation features of the channeled blade significantly higher, while visualization features were scored similarly in both groups. Both blades of the King Vision™ videolaryngoscope are reliable intubation devices in a simulated cervical spine injury in a manikin model when inserted by non-experienced operators. The channeled blade allowed faster intubation of the trachea.

Efficacy and safety of 1C class antiarrhythmic agent (propafenone) for supraventricular arrhythmias in septic shock compared to amiodarone: protocol of a prospective randomised double-blind study.

INTRODUCTION: Supraventricular arrhythmias contribute to haemodynamic compromise in septic shock. A retrospective study generated the hypothesis that propafenone could be more effective than amiodarone in achieving and maintaining sinus rhythm (SR). Certain echocardiographic parameters may predict a successful cardioversion and help in the decision on rhythm or rate control strategy. METHODS AND ANALYSIS: The trial includes septic shock patients with new-onset arrhythmia, but without severe impairment of the left ventricular ejection fraction. After baseline echocardiography, the patient is randomised to receive a bolus and maintenance dose of either amiodarone or propafenone. The primary outcome is the proportion of patients that have achieved rhythm control at 24 hours after the start of the infusion. The secondary outcomes are the percentages of patients that needed rescue treatments (DC cardioversion or unblinding and crossover of the antiarrhythmics), the recurrence of arrhythmias, intensive care unit mortality, 28-day and 1-year mortality. In the posthoc analysis, we separately assess subgroups of patients with pulmonary hypertension and right ventricular dysfunction. In the exploratory part of the study, we assess whether the presence of a transmitral diastolic A wave and its higher velocity-time integral is predictive for the sustainability of mechanical SR and whether the indexed left atrial endsystolic volume is predictive of recurrent arrhythmia. Considering that the restoration of SR within 24 hours occurred in 74% of the amiodarone-treated patients and in 89% of the patients treated with propafenone, we plan to include 200 patients to have an 80% chance to demonstrate the superiority of propafenone at p=0.05. ETHICS AND DISSEMINATION: The trial is recruiting patients according to its second protocol version approved by the University Hospital Ethical Board on the 6 October 2017 (No. 1691/16S-IV). The results will be disseminated through peer reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: NCT03029169.

Management of arrhythmia in sepsis and septic shock.

The occurrence of supraventricular arrhythmias is associated with an unfavourable prognosis in septic shock. Available trials are difficult to apply in sepsis and septic shock patients due to included cohorts, control groups and because "one size does not fit all". The priorities in the critically ill are maintenance of the sinus rhythm and diastolic ventricular filling. The rate control modality should be reserved for chronic AF and in situations when the sinus rhythm is difficult to maintain due to extreme stress conditions resulting from a high dosage of vasoactive agents. Electric cardioversion is indicated in unstable patients with an absence of contraindications and is more feasible in combination with an antiarrhythmic agent. Besides amiodarone being preferred for its lower cardiodepressant side effect compared to other agents, drugs with a different degree of betablocking activity are very useful in supraventricular arrhythmias and septic shock, providing echocardiography is routinely used to support their indications within the current summary of product characteristics. A typical patient benefiting from propafenone is without significant structural heart disease, i.e. typically with normal to moderately reduced left ventricular systolic function. Future research should be channelled towards echocardiography-guided prospective controlled trials on antiarrhythmic therapy which may clarify the issue of rhythm versus rate control, the effects of various antiarrhythmic drugs, and a place for electric cardioversion in critically ill patients in septic shock.