Yong Il Min

Association between mean arterial blood gas tension and outcome in cardiac arrest patients treated with therapeutic hypothermia

BACKGROUND Studies investigating the relationship between blood gas tension and outcome in cardiac arrest survivors have reported conflicting results. This might have resulted from the use of a blood gas value at a single time point and the difference in the proportion of patients treated with therapeutic hypothermia (TH). We investigated the association of the mean blood gas tensions calculated from blood gas values obtained between restoration of spontaneous circulation and end of TH with the outcome in cardiac arrest patients treated with TH. METHODS This was a retrospective observational study including 213 adult cardiac arrest patients. The cohort was divided into four categories based on the distribution of the mean Pao2 data using quartiles as cut-off values between categories. According to the mean Paco2, the cohort was divided into hypocarbia, normocarbia, and hypercarbia. The primary outcome was in-hospital mortality. RESULTS In multivariate analysis, the mean Pao2 quartile was not associated with in-hospital mortality, but hypocarbia was significantly associated with increased risk of in-hospital mortality (odds ratio 2.522; 95% confidence interval 1.184-5.372; P = .016). We found a V-shaped independent association between the mean Pao2 and poor neurologic outcome at hospital discharge, with the risk of poor neurologic outcome increasing with a descending and ascending Pao2 ranges. CONCLUSION Mean Pao2 had no independent association with in-hospital mortality whereas hypocarbia was independently associated with in-hospital mortality. We also found a V-shaped independent association between the mean Pao2 and poor neurologic outcome at hospital discharge.

Caustic injury: can CT grading system enable prediction of esophageal stricture?

Background. The aim of this study was to test the utility of our computed tomography (CT) grading system, compared with endoscopy, for association with the development of esophageal stricture in patients with caustic ingestion. Methods. This retrospective case series involved 49 patients with caustic ingestion from 1998 to 2009. The degree of esophageal damage was graded using a scoring system based on the extent of esophageal wall edema and the damage in adjacent tissue as seen on thoracoabdominal CT scans. The presence of esophageal stricture was established by esophagography. Diagnostic performance was compared using receiver operating characteristic (ROC) analysis. Sensitivity and specificity were calculated for the grading system. Results. The CT grading score results showed that grade III was the most common injury (20 cases, 40.8%), followed by grade IV (14 cases, 28.6%), grade II (9 cases, 18.4%), and grade I (6 cases, 12.2%). In addition, damage to the esophagus was significantly correlated with esophageal stricture when the extent of damage approached grades III and IV (p < 0.001). The CT grading system for esophageal stricture resulted in a slightly larger area under the receiver operating characteristic curve (0.90) compared with endoscopic grading system (0.79). The sensitivity and specificity of CT grading system were moderately higher than those of endoscopic grading system. Conclusion. Assessment of the degree of esophageal damage using CT, a noninvasive modality, in patients who visit the emergency department following caustic ingestion should be useful in estimating the occurrence of complications including esophageal stricture.

Correlation between initial serum levels of lactate after return of spontaneous circulation and survival and neurological outcomes in patients who undergo therapeutic hypothermia after cardiac arrest

OBJECTIVES We analysed the relationship between serum levels of lactate within 1h of return of spontaneous circulation (ROSC) and survival and neurological outcomes in patients who underwent therapeutic hypothermia (TH). METHODS This was a multi-centre retrospective and observational study that examined data from the first Korean Hypothermia Network (KORHN) registry from 2007 to 2012. The inclusion criteria were out-of-hospital cardiac arrest (OHCA) and examination of serum levels of lactate within 1h after ROSC, taken from KORHN registry data. The primary endpoint was survival outcome at hospital discharge, and the secondary endpoint was poor neurological outcome (Cerebral Performance Category, CPC, 3-5) at hospital discharge. Initial lactate levels and other variables collected within 1h of ROSC were analysed via multivariable logistic regression. RESULTS Data from 930 cardiac arrest patients who underwent TH were collected from the KORHN registry. In a total of 443 patients, serum levels of lactate were examined within 1h of ROSC. In-hospital mortality was 289/443 (65.24%), and 347/443 (78.33%) of the patients had CPCs of 3-5 upon hospital discharge. The odds ratios of lactate levels for CPC and in-hospital mortality were 1.072 (95% confidence interval (CI) 1.026-1.121) and 1.087 (95% CI=1.031-1.147), respectively, based on multivariate ordinal logistic regression analyses. CONCLUSION High levels of lactate in serum measured within 1h of ROSC are associated with hospital mortality and high CPC scores in cardiac arrest patients treated with TH.

Outcome and adverse events with 72-hour cooling at 32°C as compared to 24-hour cooling at 33°C in comatose asphyxial arrest survivors.

PURPOSE Studies suggest that the current therapeutic hypothermia (TH) protocol does not improve outcomes in adult asphyxial arrest survivors. We sought to compare the effect of 24-hour cooling at 33°C vs that of 72-hour cooling at 32°C on outcomes and the incidence of adverse events in unconscious asphyxial arrest survivors. METHODS Retrospectively collected data on 79 consecutive asphyxial arrest patients treated with TH from January 2006 to March 2013 were analyzed. Forty-one patients who presented between January 2006 and January 2011 formed the 33°C-24 h group, whereas 38 patients who presented between February 2011 and March 2013 formed the 32°C-72 h group. The primary outcome was neurologic outcome at 30 days following arrest. The secondary outcomes were all-cause mortality at 30 days following arrest and the incidence of adverse events. RESULTS The Kaplan-Meier curve showed no significant difference in survival over time during the 30 days after arrest between the 2 groups (P = .608). Good neurologic outcome was achieved in only 2 patients (2.5%) of the overall cohort, despite TH. One of the 32°C-72 h group (2.6%; 95% confidence interval, 4.7%-13.5%) had a good neurologic outcome, as did one of the 33°C-24 h group (2.4%; 95% confidence interval, 4.3%-12.6%) (P = 1.000). There were no significant differences in the rates of adverse events between the 2 groups. CONCLUSION The present study did not demonstrate an advantage of 72-hour cooling at 32°C in unconscious asphyxial arrest patients compared with 24-hour cooling at 33°C.

Variable effects of high-dose adrenaline relative to standard-dose adrenaline on resuscitation outcomes according to cardiac arrest duration.

AIM OF THE STUDY Adjustment of adrenaline (epinephrine) dosage according to cardiac arrest (CA) duration, rather than administering the same dose, may theoretically improve resuscitation outcomes. We evaluated variable effects of high-dose adrenaline (HDA) relative to standard-dose adrenaline (SDA) on resuscitation outcomes according to CA duration. METHODS Twenty-eight male domestic pigs were randomised to the following 4 groups according to the dosage of adrenaline (SDA 0.02 mg/kg vs. HDA 0.2mg/kg) and duration of CA before beginning cardiopulmonary resuscitation (CPR): 6 min SDA, 6 min HDA, 13 min SDA, or 13 min HDA. After the predetermined duration of untreated ventricular fibrillation, CPR was provided. RESULTS All animals in the 6 min SDA, 6 min HDA, and 13 min HDA groups were successfully resuscitated, while only 4 of 7 pigs in the 13 min SDA group were successfully resuscitated (p=0.043). HDA groups showed higher right atrial pressure, more frequent ventricular ectopic beats, higher blood glucose, higher troponin-I, and more severe metabolic acidosis than SDA groups. Animals of 13 min groups showed more severe metabolic acidosis and higher troponin-I than animals of 6 min groups. All successfully resuscitated animals, except two animals in the 13 min HDA group, survived for 7 days (p=0.121). Neurologic deficit score was not affected by the dose of adrenaline. CONCLUSION HDA showed benefit in achieving restoration of spontaneous circulation in 13 min CA, when compared with 6 min CA. However, this benefit did not translate into improved long-term survival or neurologic outcome.

Impact of case volume on outcome and performance of targeted temperature management in out-of-hospital cardiac arrest survivors

PURPOSE This study aimed to determine the effect of case volume on targeted temperature management (TTM) performance, incidence of adverse events, and neurologic outcome in comatose out-of-hospital cardiac arrest (OHCA) survivors treated with TTM. METHODS We used a Web-based, multicenter registry (Korean Hypothermia Network registry), to which 24 hospitals throughout the Republic of Korea participated to study adult (≥18 years) comatose out-of-hospital cardiac arrest patients treated with TTM between 2007 and 2012. The primary outcome was neurologic outcome at hospital discharge. The secondary outcomes were inhospital mortality, TTM performance, and adverse events. We extracted propensity-matched cohorts to control for bias. Multivariate logistic regression analysis was performed to assess independent risk factors for neurologic outcome. RESULTS A total of 901 patients were included in this study; 544 (60.4%) survived to hospital discharge, and 248 (27.5%) were discharged with good neurologic outcome. The high-volume hospitals initiated TTM significantly earlier and had lower rates of hyperglycemia, bleeding, hypotension, and rebound hyperthermia. However, neurologic outcome and inhospital mortality were comparable between high-volume (27.7% and 44.6%, respectively) and low-volume hospitals (21.1% and 40.5%) in the propensity-matched cohorts. The adjusted odds ratio for the high-volume hospitals compared with low-volume hospitals was 1.506 (95% confidence interval, 0.875-2.592) for poor neurologic outcome. CONCLUSIONS Higher TTM case volume was significantly associated with early initiation of TTM and lower incidence of adverse events. However, case volume had no association with neurologic outcome and inhospital mortality.

The Performances of Standard and ResMed Masks During Bag–Valve–Mask Ventilation

Abstract 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.

Rapidly induced selective cerebral hypothermia using a cold carotid arterial flush during cardiac arrest in a dog model

PURPOSE The present study was undertaken to determine whether flushing the carotid artery with normal saline at 4 degrees C (hypothermic carotid arterial flush, HCAF) during cardiac arrest can achieve selective cerebral hypothermia rapidly during cardiac arrest and improve cerebral outcome. METHODS Ventricular fibrillation (VF) was induced in fourteen dogs and circulatory arrest was maintained for 9 min. Dogs were then resuscitated by cardiopulmonary resuscitation. The dogs were divided into two groups; a control group (n=7), which underwent precisely the same procedure as the experimental group but not HCAF, and an experimental group (HCAF group; n=7), which received HCAF from 8 min after the onset of VF. RESULTS Two dogs in the control group and in the HCAF group died within 72 h after the recovery of spontaneous circulation (ROSC) due to extracerebral complications. The remaining 10 dogs survived to final evaluation at 72 h post-ROSC. In the HCAF group, tympanic temperature decreased from 37.7 degrees C (37.5-37.8) to 34 degrees C in 1 min (1-1.5) from the start of HCAF and was maintained below 34 degrees C until 6.5 min (3-12) after the start of HCAF, whereas oesophageal and rectal temperatures were maintained above 35 degrees C. Neurological deficit scores (0-100%) at 72 h post-ROSC were 42.4% (27.0-80.6) in the control group and 18.4% (14.0-36.0) in the HCAF group (p<0.05). CONCLUSION HCAF induced selective cerebral hypothermia rapidly during cardiac arrest and improved neurological deficit scores after 9 min of no blood flow in the described canine cardiac arrest model.

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.

Relationship between timing of cooling and outcomes in adult comatose cardiac arrest patients treated with targeted temperature management

AIM OF THE STUDY Studies examining associations between time to target temperature and outcomes in cardiac arrest patients who underwent targeted temperature management (TTM) have shown inconsistent results. We examined these associations separately for time from restoration of spontaneous circulation to TTM initiation (pre-induction time) and time from TTM initiation to target temperature (induction time). Furthermore, we examined whether critical time thresholds exist if there is an association. METHODS This was a single-centre retrospective observational study including adult cardiac arrest patients treated with TTM from 2008 to 2015. We tested the associations of pre-induction time and induction time with outcomes at hospital discharge using multivariate logistic regression analysis. We then performed additional multivariate analyses, each with the significant timing variable at different binary cutoffs. RESULTS A total of 515 patients were analysed. At hospital discharge, 357 patients (69.3%) were alive, of whom 161 (31.3%) had a favourable neurologic outcome. In multivariate analysis, a shorter pre-induction time was independently associated with a favourable neurologic outcome (odds ratio [OR], 1.110; 95% confidence interval [CI], 1.025-1.202), whereas the induction time was not (OR, 0.954; 95% CI, 0.852-1.067). We found two pre-induction time thresholds (120 and 360min) that were associated with neurologic outcome. CONCLUSION We found that a shorter pre-induction time was independently associated with a favorable neurologic outcome at hospital discharge, whereas induction time was not. We also found two time thresholds at 120 and 360min, after which initiation of cooling was associated with a worse neurologic outcome.