Tag Archives: arrest

Cardiac arrest drugs and pupils

Although not predictive immediately post-cardiac arrest in the emergency department, dilated unreactive pupils two or three days later on the ICU may indicate a hopeless prognosis. We know from our experience with adrenaline (epinephrine) infusions that this drug does not prevent pupils from reacting to light, but what about atropine?

A letter by Dr Sophie MacDougall-Davis in Resuscitation describes a 66 year old male patient admitted to the ICU after an intraoperative PEA arrest during which he received 3 mg intravenous atropine. Post arrest and post anaesthesia he was awake with no neurological deficit, but eight hours after the cardiac arrest his pupils remained fixed and dilated, and were dilated with only a very slight reaction the next morning and remained sluggish at forty-eight hours, normalising at seventy-two hours. A possible reason for its prolonged action may be uptake of atropine from the plasma into the aqueous humor of the eye, followed by its slow release.
Dr MacDougall-Davis cautions:

When assessing pupils in comatose cardiac arrest survivors, the potential for atropine to have a prolonged effect on pupil size and reactivity should be considered.

Atropine, fixed dilated pupils and prognostication following cardiac arrest
Resuscitation. 2011 Feb;82(2):232

ECLS on Japanese, in Japanese

A review of extracorporeal life support for out-of-hospital cardiac arrest was undertaken, looking specifically at studies published in the Japanese literature. The abstract is shown below. Based on these findings, inclusion criteria for a multicentre, prospective non-randomised cohort study were established. The ‘SAVE-J: Study of advanced life support for ventricular fibrillation with extracorporeal circulation in Japan’ was launched and has been ongoing since October 2008 to compare the proportion of patients with a favourable neurological outcome by intention-to-treat in an ECPR group with a non-ECPR group. Inclusion criteria for this new study are:

  1. shockable rhythm on the initial ECG
  2. cardiac arrest on arrival at hospital regardless of the presence of recovery of spontaneous circulation before arrival
  3. arrival at hospital within 45 min of the call for an ambulance or cardiac arrest;
  4. cardiac arrest remaining for more than 15 min after arrival at hospital.

I look forward to seeing the results SAVE-J. If you wish to read more, you can check out the SAVE-J study website.

AIM: Although favourable outcomes in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest have been frequently reported in Japanese journals since the late 1980s, there has been no meta-analysis of ECPR in Japan. This study reviewed and analysed all previous studies in Japan to clarify the survival rate of patients receiving ECPR.
MATERIAL AND METHODS: Case reports, case series and abstracts of scientific meetings of ECPR for out-of-hospital cardiac arrest written in Japanese between 1983 and 2008 were collected. The characteristics and outcomes of patients were investigated, and the influence of publication bias of the case-series studies was examined by the funnel-plot method.
RESULTS: There were 1282 out-of-hospital cardiac arrest patients, who received ECPR in 105 reports during the period. The survival rate at discharge given for 516 cases was 26.7±1.4%. The funnel plot presented the relationship between the number of cases of each report and the survival rate at discharge as the reverse-funnel type that centred on the average survival rate. In-depth review of 139 cases found that the rates of good recovery, mild disability, severe disability, vegetative state, death at hospital discharge and non-recorded in all cases were 48.2%, 2.9%, 2.2%, 2.9%, 37.4% and 6.4%, respectively.
CONCLUSIONS: Based on the results of previous reports with low publication bias in Japan, ECPR appears to provide a higher survival rate with excellent neurological outcome in patients with out-of-hospital cardiac arrest.

Extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: a review of the Japanese literature
Resuscitation. 2011 Jan;82(1):10-4

Which cardiac arrest survivors have a positive angio?

A retrospective study of out-of-hospital cardiac arrest patients attended by a French pre-hospital system was performed to assess the predictive factors for positive coronary angiography.

OBJECTIVES: Coronary angiography is often performed in survivors of out-of-hospital cardiac arrest, but little is known about the factors predictive of a positive coronary angiography. Our aim was to determine these factors.
METHODS: In this 7-year retrospective study (January 2000-December 2006) conducted by a French out-of-hospital emergency medical unit, data were collected according to Utstein style guidelines on all out-of-hospital cardiac arrest patients with suspected coronary disease who recovered spontaneous cardiac activity and underwent early coronary angiography. Coronary angiography was considered positive if a lesion resulting in more than a 50% reduction in luminal diameter was observed or if there was a thrombus at an occlusion site.
RESULTS: Among the 4621 patients from whom data were collected, 445 were successfully resuscitated and admitted to hospital. Of these, 133 were taken directly to the coronary angiography unit, 95 (71%) had at least one significant lesion, 71 (53%) underwent a percutaneous coronary intervention, and 30 survived [23%, 95% confidence interval (CI): 16-30]. According to multivariate analysis, the factors predictive of a positive coronary angiography were a history of diabetes [odds ratio (OR): 7.1, 95% CI: 1.4-36], ST segment depression on the out-of-hospital ECG (OR: 5.4, 95% CI: 1.1-27.8), a history of coronary disease (OR: 5.3, 95% CI: 1.4-20.1), cardiac arrest in a public place (OR: 3.7, 95% CI: 1.3-10.7), and ventricular fibrillation or ventricular tachycardia as initial rhythm (OR: 3.1, 95% CI: 1.1-8.6).
CONCLUSION: Among the factors identified, diabetes and a history of coronary artery were strong predictors for a positive coronary angiography, whereas ST segment elevation was not as predictive as expected.

Predictive factors for positive coronary angiography in out-of-hospital cardiac arrest patients
Eur J Emerg Med. 2011 Apr;18(2):73-6

Nasal cooling method

More data on the RhinoChill device from an in-hospital study of post-cardiac arrest patients in Germany. The RhinoChill device (BeneChill Inc., San Diego, USA) allows evaporative cooling by spraying an inert liquid coolant (a perfluorochemical) into the nasal cavity. The liquid evaporates instantaneously, thereby removing heat. It can make your nose discoloured, and in one patient with cardiogenic shock, tissue damage of nose and cheeks due to freezing occurred. Several of the authors are linked with the company that manufactures the device.

AIM: Mild therapeutic hypothermia improves survival and neurologic recovery in primary comatose survivors of cardiac arrest. Cooling effectivity, safety and feasibility of nasopharyngeal cooling with the RhinoChill device (BeneChill Inc., San Diego, USA) were determined for induction of therapeutic hypothermia.
METHODS: Eleven emergency departments and intensive care units participated in this multi-centre, single-arm descriptive study. Eighty-four patients after successful resuscitation from cardiac arrest were cooled with nasopharyngeal delivery of an evaporative coolant for 1h. Subsequently, temperature was controlled with systemic cooling at 33 degrees C. Cooling rates, adverse events and neurologic outcome at hospital discharge using cerebral performance categories (CPC; CPC 1=normal to CPC 5=dead) were documented. Temperatures are presented as median and the range from the first to the third quartile.
RESULTS: Nasopharyngeal cooling for 1h reduced tympanic temperature by median 2.3 (1.6; 3.0) degrees C, core temperature by 1.1 (0.7; 1.5) degrees C. Nasal discoloration occurred during the procedure in 10 (12%) patients, resolved in 9, and was persistent in 1 (1%). Epistaxis was observed in 2 (2%) patients. Periorbital gas emphysema occurred in 1 (1%) patient and resolved spontaneously. Thirty-four of 84 patients (40%) patients survived, 26/34 with favorable neurological outcome (CPC of 1-2) at discharge.
CONCLUSIONS: Nasopharyngeal evaporative cooling used for 1h in primary cardiac arrest survivors is feasible and safe at flow rates of 40-50L/min in a hospital setting.
Safety and feasibility of nasopharyngeal evaporative cooling in the emergency department setting in survivors of cardiac arrest
Resuscitation. 2010 Aug;81(8):943-9

End tidal CO2 in cardiac arrest

Measuring end-tidal CO2 in cardiac arrest patients is helpful for

  1. confirming tracheal tube placement
  2. assessing the effectiveness of chest compressions
  3. predicting likelihood of return of spontaneous circulation (ROSC), in that a persistently low ETCO2 tends to predict death, whereas a high or rising ETCO2 is associated with a higher chance of ROSC.

It may be however that its predictive ability depends on the type of cardiac arrest, and how far into the resuscitation you’ve got when you measure the ETCO2. Consider this new study from Slovenian pre-hospital emergency physicians:
Methods: The study included two cohorts of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity (PEA), and cardiac arrest due to arrhythmia with initial rhythm VF or pulseless VT. The causes of asphyxia were: asthma, severe acute respiratory failure, tumor of the airway, suicide by hanging, acute intoxication, pneumonia and a foreign body in the airway.PetCO2 was measured for both groups immediately after intubation and repeatedly every minute, both for patients with or without return of spontaneous circulation (ROSC). We compared the dynamic pattern of PetCO2 between groups. Resuscitation procedures were performed by an emergency medical team (emergency medical physician and two emergency medical technicians or registered nurses) in accordance with 2005 ERC Guideline
Results: Between June 2006 and June 2009 resuscitation was attempted in 325 patients and in this study we included 51 patients with asphyxial cardiac arrest and 63 patients with VF/VT cardiac arrest. The initial values of PetCO2 were significantly higher in the group with asphyxial cardiac arrest (6.74 ± 4.22 kilopascals (kPa) versus 4.51 ± 2.47 kPa; P = 0.004). In the group with asphyxial cardiac arrest, the initial values of PetCO2 did not show a significant difference when we compared patients with and without ROSC (6.96 ± 3.63 kPa versus 5.77 ± 4.64 kPa; P = 0.313). We confirmed significantly higher initial PetCO2 values for those with ROSC in the group with primary cardiac arrest (4.62 ± 2.46 kPa versus 3.29 ± 1.76 kPa; P = 0.041).

A significant difference in PetCO2 values for those with and without ROSC was achieved after five minutes of CPR in both groups (asphyxial arrest: 6.09 ± 2.63 kPa versus 4.47 ± 3.35 kPa; P = 0.006; primary arrest: 5.63 ± 2.01 kPa versus 4.26 ± 1.86; P = 0.015)
In mmHg, the PetCO2 values for those with and without ROSC after five minutes of CPR was: asphyxial arrest: 42.3 ± 20 mmHg versus 34 ± 25.5 mmHg; P = 0.006; primary arrest: 42.8 ± 15.3 mmHg versus 32.3 ± 14.1 mmHg; P = 0.015
Graphically, this difference in ROSC vs non-ROSC PetCO2 for both groups appeared to be even greater at ten minutes, with higher statistically significance (p<0.001), although the values of PetCO2 are not given in the paper.
In all patients with ROSC the initial PetCO2 was again higher than 1.33 kPa (10.1 mmHg).
Conclusions: The dynamic pattern of PetCO2 values during out-of-hospital CPR showed higher values of PetCO2 in the first two minutes of CPR in asphyxia, and a prognostic value of initial PetCO2 only in primary VF/VT cardiac arrest. A prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until final values. This difference seems to be a useful criterion in pre-hospital diagnostic procedures and attendance of cardiac arrest.
The authors summarise with the following key messages:

  • Initial values of PetCO2 are higher in asphyxial cardiac arrest than in primary cardiac arrest.
  • Initial values of PetCO2 in asphyxial cardiac arrest do not have a prognostic value for resuscitation outcome.
  • The prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until the final values.
  • The values of PetCO2 seem to be useful in differentiating the causes of cardiac arrest in a pre-hospital setting.

I think that last one’s a bit of a stretch. For me, this paper confirms that the longer you are into a cardiac arrest resuscitation, the worse news a low PetCO2 is. The lack of predictive value of initial PetCO2, particularly in the asphyxia group, is interesting but not surprising.
The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest
Critical Care 2011, 15:R13

Pre-hospital therapeutic hypothermia

A Czech study demonstrated effective pre-hospital therapeutic cooling of post-cardiac arrest patients using fairly modest amounts of intravenous saline at 4°C: the administration of 12.6 ± 6.4 mL/kg (1,032 ± 546 mL) of 4°C normal saline led to a tympanic temperature decrease of 1.4 ± 0.8°C (from 36.2 ± 1.5 to 34.7 ± 1.4°C; P < 0.001) in 42.8 ± 19.6 minutes. No ice packs were applied.

Before other emergency medical services adopt this, it should be noted that all these patients were managed in the field by emergency physicians who administered sedatives and neuromuscular blockers. It’s a European thing.
Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline
Critical Care 2010, 14:R231 Full text

Extracorporeal CPR

Extracorporeal cardiopulmonary resuscitation (E-CPR) using extracorporeal membrane oxygenation (ECMO) support during inhospital cardiac arrest has been attempted to improve the outcome of cardiopulmonary resuscitation (CPR). A retrospective, single-center, observational study from Korea analysed a total of 406 adult patients with witnessed inhospital cardiac arrest receiving cardiopulmonary resuscitation for >10 mins.
How their system works: An ECMO cart was transported to the CPR site within 5–10 mins during the day and within 10–20 mins during the night shift. The decision to use E-CPR was dependent on the CPR team leader. Application of ECMO was usually considered under conditions of prolonged arrest (when there was no ROSC after 10–20 mins of CPR), recurrent arrest (when ROSC could not be maintained), or when the patient could not be expected to recover as a result of underlying severe left ventricular dysfunction or coronary artery disease despite a short CPR duration (end-stage heart failure requiring transplantation, left main coronary artery occlusion, etc)
The primary end point was a survival discharge with minimal neurologic impairment.

No. ECMO. I said ECMO.

85 patients underwent E-CPR and 321 underwent C- CPR. ECMO implantation was successful in 94.1% (80 of 85) in the E-CPR group, except for three cannulation failures and two ECMO flow failures. There was a signficantly greater proportion of patients with primary cardiac disease in the E-CPR group. Propensity score matching was used to balance the baseline characteristics and cardiopulmonary resuscitation variables that could potentially affect prognosis. In the matched population (n = 120), the survival discharge rate with minimal neurologic impairment in the extracorporeal cardiopulmonary resuscitation group was significantly higher than that in the conventional cardiopulmonary resuscitation group (odds ratio of mortality or significant neurologic deficit, 0.17; 95% confidence interval, 0.04-0.68; p = .012). In addition, there was a significant difference in the 6-month survival rates with minimal neurologic impairment (hazard ratio, 0.48; 95% confidence interval, 0.29-0.77; p = .003; p <.001 by stratified log-rank test). In the subgroup based on cardiac origin, extracorporeal cardiopulmonary resuscitation also showed benefits for survival discharge (odds ratio, 0.19; 95% confidence interval, 0.04-0.82; p = .026) and 6-month survival with minimal neurologic impairment (hazard ratio, 0.56; 95% confidence interval, 0.33-0.97; p = .038; p = .013 by stratified log-rank test).
The authors conclude that extracorporeal cardiopulmonary resuscitation showed a survival benefit over conventional cardiopulmonary resuscitation in patients who received cardiopulmonary resuscitation for >10 mins after witnessed inhospital arrest, especially in cases of cardiac origin. These results contrast with these recently published French findings in patients receiving ECMO after out-of-hospital cardiac arrest.
Extracorporeal cardiopulmonary resuscitation in patients with inhospital cardiac arrest: A comparison with conventional cardiopulmonary resuscitation
Crit Care Med. 2011 Jan;39(1):1-7

Better outcomes with conventional CPR

A very large nationwide Japanese observational study examined outcomes in out-of-hospital cardiac arrest patients who received CPR from lay rescuers. They compared conventional CPR (with mouth-to-mouth and chest compressions) with compression-only CPR. Over 40 000 patients were included.
Conventional CPR was associated with better outcomes than chest compression only CPR, for both one month survival (adjusted odds ratio 1.17, 95% confidence interval 1.06 to 1.29) and neurologically favourable one month survival (1.17, 1.01 to 1.35). Neurologically favourable one month survival decreased with increasing age and with delays of up to 10 minutes in starting CPR for both conventional and chest compression only CPR. The benefit of conventional CPR over chest compression only CPR was significantly greater in younger people in non-cardiac cases (P=0.025) and with a delay in start of CPR after the event was witnessed in non-cardiac cases (P=0.015) and all cases combined (P=0.037).
The authors conclude that conventional CPR is associated with better outcomes than chest compression only CPR for selected patients with out of hospital cardiopulmonary arrest, such as those with arrests of non-cardiac origin and younger people, and people in whom there was delay in the start of CPR.
Outcomes of chest compression only CPR versus conventional CPR conducted by lay people in patients with out of hospital cardiopulmonary arrest witnessed by bystanders: nationwide population based observational study
BMJ 2011; 2011; 342:c7106 Full Text

Hypothermia and hypokalaemia

We all like to treat selected post cardiac arrest patients with hypothermia now, but isn’t hypothermia associated with a drop in potassium, which of course can precipitate pesky ventricular dysrhythmias in patients who would really rather not arrest again. Maybe the hypothermia itself is protective against the dysrhythmias?
A study from the Mayo Clinic updates our knowledge of this area:

METHODS: We retrospectively analyzed potassium variability with Therapeutic Hypothermia (TH) and performed correlative analysis of QT intervals and the incidence of ventricular arrhythmia.
RESULTS: We enrolled 94 sequential patients with OHCA, and serum potassium was followed intensively. The average initial potassium value was 3.9±0.7 mmol/l and decreased to a nadir of 3.2±0.7 mmol/l at 10 h after initiation of cooling (p<0.001). Eleven patients developed sustained polymorphic ventricular tachycardia (PVT) with eight of these occurring during the cooling phase. The corrected QT interval prolonged in relation to the development of hypothermia (p<0.001). Hypokalemia was significantly associated with the development of PVT (p=0.002), with this arrhythmia being most likely to develop in patients with serum potassium values of less than 2.5 mmol/l (p=0.002). Rebound hyperkalemia did not reach concerning levels (maximum 4.26±0.8 mmol/l at 40 h) and was not associated with the occurrence of ventricular arrhythmia. Furthermore, repletion of serum potassium did not correlate with the development of ventricular arrhythmia.
CONCLUSIONS: Therapeutic hypothermia is associated with a significant decline in serum potassium during cooling. Hypothermic core temperatures do not appear to protect against ventricular arrhythmia in the context of severe hypokalemia and cautious supplementation to maintain potassium at 3.0 mmol/l appears to be both safe and effective.
Hypokalemia during the cooling phase of therapeutic hypothermia and its impact on arrhythmogenesis
Resuscitation. 2010 Dec;81(12):1632-6