Association of blood glucose variability with outcomes in comatose cardiac arrest survivors treated with therapeutic hypothermia.

PURPOSE: A recent study showed that increased blood glucose variability was an independent predictor of mortality in cardiac arrest survivors treated with therapeutic hypothermia (TH). We hypothesized that the association of blood glucose variability with outcomes would differ depending on the TH phase, as body temperature affects glucose homeostasis. METHODS: A retrospective cohort of 147 consecutive cardiac arrest patients treated with TH was analyzed. Mean absolute glucose change (MAGC) was calculated using blood glucose values during the entire TH period and during each TH phase (induction, from the TH initiation to the achievement of the target temperature; maintenance, 24 hours from the end of induction; and rewarming, from the end of the maintenance to the achievement of 36.5°C). The primary and secondary outcomes were mortality and neurological outcome at 30 days. Multivariate regression analyses were performed with variables with a significance level <0.1 on univariate analyses. RESULTS: The hypoglycemia rate increased significantly during the rewarming phase compared with the maintenance phase (P = .003). The MAGC during the TH maintenance phase was an independent predictor of mortality (OR = 1.056, 95% CI 1.008-1.107, P = .023) and unfavorable neurologic outcome (OR = 1.202, 95% CI 1.043-1.384, P = .038), while the MAGC during the rewarming phase and the entire TH period were not. CONCLUSION: The increased MAGC during the TH maintenance phase was associated with mortality and unfavorable neurologic outcome. However, this study cannot prove a causal association due to the retrospective design. In addition, we showed that the hypoglycemia rate increased significantly during the rewarming phase.

Estimation of central venous pressure using inferior vena caval pressure from a femoral endovascular cooling catheter.

PURPOSE: Endovascular cooling using the femoral cooling catheter is widely practiced. Central venous pressure (CVP) monitoring in patients undergoing femoral endovascular cooling may require the placement of another catheter near the right atrium (RA). We sought to estimate the agreement between the CVP recorded from catheters placed in the superior vena caval pressure (SVCP) and the inferior vena caval pressure (IVCP) recorded from the femoral cooling catheter in patients undergoing femoral endovascular cooling. METHODS: We enrolled adult cardiac arrest survivors undergoing femoral endovascular cooling. A commercially available central venous catheter was placed in the SVC (superior vena cava) near the RA via subclavian venous access. Both SVCP and IVCP were recorded every 4 hours during therapeutic hypothermia. Arterial pressure, heart rate, peak inspiratory pressure (PIP), and positive end expiratory pressure (PEEP) at the time of vena caval pressure measurements were obtained. RESULTS: A total of 323 pairs of SVCP and IVCP measurements were collected. The correlation coefficient between SVCP and IVCP was 0.965 (P < .001). The mean difference between SVCP and IVCP was -0.45 mm Hg (SD, 1.27; 95% confidence interval, -0.59 to -0.31 mm Hg). The limits of agreement were -2.94 to 2.05 mm Hg. Vena caval pressures were significantly correlated with airway pressures (peak inspiratory pressure and positive end expiratory pressure), whereas the difference between SVCP and IVCP did not correlate with airway pressures. CONCLUSION: Inferior vena caval pressure measured via the femoral cooling catheter showed excellent agreement with CVP recorded from catheters placed in the SVC, which indicates that the femoral cooling catheter can be used for monitoring CVP.

Potassium induced cardiac standstill during conventional cardiopulmonary resuscitation in a pig model of prolonged ventricular fibrillation cardiac arrest: a feasibility study.

AIM OF THE STUDY: Potassium-based cardioplegia has been the gold standard for cardioprotection during cardiac surgery. We sought to evaluate the feasibility and the effects of potassium-induced cardiac standstill during conventional cardiopulmonary resuscitation (CPR) in a pig model of prolonged ventricular fibrillation (VF). METHODS: VF was induced in 20 pigs, and circulatory arrest was maintained for 14 min. Animals were then resuscitated by standard CPR. Coincident with the start of CPR, 20 ml of saline (control group) or 0.9 mequiv.kg(-1) of potassium chloride diluted to 20 ml (potassium group) was administered into right atrium. RESULTS: Administration of potassium resulted in asystole lasting for 1.0 min (0.2) in the potassium group animals. VF reappeared in all but one animal, in which wide QRS complex bradycardia followed. Restoration of spontaneous circulation (ROSC) was attained in two animals (20%) in the control group and in seven animals (70%) in the potassium group (p=0.070). Resuscitated animals in the potassium group required fewer countershocks (3, 4 vs. 2 (1-2)), smaller doses of adrenaline (1.84, 1.84 vs. 0.94 (0.90-1.00)mg), and shorter duration of CPR (8, 10 vs. 4.0 (4.0-4.0)min) than did the control group. Potassium concentrations normalised rapidly after ROSC in both groups, and the potassium concentrations at 5 min (5.5, 6.6 vs. 6.8 (6.5-7.8)mequiv.l(-1)) and 4h (4.9, 5.4 vs. 5.9 (5.1-6.4)mequiv.l(-1)) after ROSC were similar in the both groups. CONCLUSION: In a pig model of untreated VF cardiac arrest for 14 min, resuscitation with potassium-induced cardiac standstill during conventional CPR was found to be feasible.

The performances of standard and ResMed masks during bag-valve-mask ventilation.

BACKGROUND: A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. OBJECTIVE: In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. METHODS: Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. RESULTS: BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. CONCLUSIONS: BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

A case of near-fatal fenpyroximate intoxication: the role of percutaneous cardiopulmonary support and therapeutic hypothermia.

INTRODUCTION: Fenpyroximate is a potent inhibitor of the mitochondrial proton-translocating NADH-quinone oxidoreductase (complex I). Although it is widely used as an acaricide, data on the acute toxicity of fenpyroximate in humans are very limited. CASE DETAIL: A 44-year-old woman was brought to our hospital with a reduced level of consciousness, hypotension, and severe lactic acidosis after deliberate ingestion of 5% fenpyroximate solution. The acidosis progressively deteriorated despite maximal supportive treatment, and cardiac arrest refractory to standard cardiopulmonary resuscitation developed. The patient was successfully resuscitated with percutaneous cardiopulmonary support, therapeutic hypothermia, and intravenous acetylcysteine. Blood gases of simultaneously obtained arterial and central venous blood revealed decreased arteriovenous oxygen difference. DISCUSSION: The present case, along with previous cases of fatal complex I inhibitor poisoning, indicates that impaired oxygen utilization at the tissue level is the major mechanism underlying the fatality of this condition. Percutaneous cardiopulmonary support may help restore vital organ perfusion by increasing oxygen delivery even in the presence of decreased oxygen consumption, thereby allowing additional time for recovery and drug metabolism. Therapeutic hypothermia also may be beneficial in treating severe complex I inhibitor poisoning, since hypothermia itself attenuates oxidative processes and decreases the metabolic rate.