Is there a self-preserving hypothermic mechanism in shock?

Hypoxia-induced hypothermia (HIH) is regarded as an adaptive response to hypoxia in a variety of creatures, but no details of the mechanism have yet been elucidated in the clinical setting. This study was designed to analyze alteration of core body temperature with hemorrhagic shock and to clarify HIH in the clinical setting. Patients were categorized in the hemorrhage shock (S, n = 15) or cardiopulmonary arrest (C, n = 88) group. The tympanic membrane temperature (TMT) was measured, and the length of the interval of call-to-arrival (CTA) at a hospital was set as the time-course parameter. There was a significant negative linear relationship between CTA interval and TMT (S group: TMT = -0.055 degrees C, CTA = +36.1 min, r = -0.833, P < 0.001; C group: TMT = -0.046 degrees C, CTA = +36.3 min, r = -0.548, P < 0.001). Analysis of variance revealed no significant difference in the slope of the regression lines of both groups. However, when the CTA interval was used as a covariate, there was a significant difference in the TMT (P = 0.014), which means that the regression line of the S group was significantly lower than that of the C group with time. Furthermore, in the S group, all patients were hypothermic (<35 degrees C) when their CTA interval was more than 20 min; on the other hand, in the C group, only 64 (75%) of 85 were hypothermic. Patients in S group were more likely to become hypothermic (P < 0.05). In humans with cellular hypoxia, HIH takes place, as seen in other animals. This result emphasizes the necessity for studies of analysis of the mechanisms of temperature control and determination of optimal body temperature during acute critical care.     

Monitoring during cardiac arrest: are we there yet?

Advancements in electronic data acquisition have translated into improved monitoring of victims of cardiac arrest, but initial techniques remain direct observation of pulses and respirations. The most essential monitor continues to be the electrocardiogram. However, monitoring diastolic blood pressure, myocardial perfusion pressure, and end-tidal carbon dioxide are extremely useful. Most of the current research on monitoring during cardiopulmonary resuscitation focuses on methods for analyzing ventricular fibrillation waveforms. By analyzing the waveform, defibrillation shocks may be delivered at the time when the chance of success is optimal. Low-amplitude and low-frequency fibrillation waveforms are associated with increased rates of asystole and pulseless electrical activity after defibrillation. Methods of analyzing the ventricular fibrillation waveform include measuring the amplitude and frequency and combining the contributions of amplitude and frequency by various methods to improve discrimination. Other types of monitoring being studied for their usefulness during cardiac arrests include sonography, Bispectral Index monitoring, tissue carbon dioxide monitors, and pupil observation. The test of these monitoring techniques is ultimately their ability to improve patient survival to hospital discharge, which is a major challenge for resuscitation researchers.     

Does compression-only cardiopulmonary resuscitation generate adequate passive ventilation during cardiac arrest?

INTRODUCTION: The need for rescue breaths in bystander CPR has been questioned after several studies have shown that omitting ventilation does not worsen outcome. Chest compression may produce passive tidal volumes large enough to provide adequate ventilation in animal studies, but no recent clinical studies have examined this phenomenon. We measured passive ventilation during optimal chest compression to determine whether compression-only CPR provides adequate gas exchange during cardiac arrest. METHODS: Adult cardiac arrest patients were treated according to European Resuscitation Council guidelines. Chest compressions were performed using a mechanical chest compression device (LUCAS) with active decompression disabled to mimic manual compression. Respiratory variables were measured during periods of compression-only CPR. RESULTS: Emergency Department data were collected during compression-only CPR from 17 patients (11 male) aged 47-82 years who had suffered an out-of-hospital cardiac arrest. Median tidal volume per compression was 41.5 ml (range 33.0-62.1 ml), being considerably less than measured deadspace in all patients. Maximum end-tidal CO2 was 0.93 kPa (range 0.0-4.6 kPa). Minute volume CO2 was 19.5 ml (range 15.9-33.8; normal range 150-180 ml). CONCLUSIONS: At an advanced stage of cardiac arrest, passive ventilation during compression-only CPR is limited in its ability to maintain adequate gas exchange, with gas transport mechanisms associated with high frequency ventilation perhaps generating a very limited gas exchange. The effectiveness of passive ventilation during the early stages of CPR, when chest and lung compliance is greater, remains to be investigated.     

Postresuscitation disease after cardiac arrest: a sepsis-like syndrome?

PURPOSE OF REVIEW: Despite advances in cardiac arrest resuscitation, neurologic impairments and other organ dysfunctions cause considerable mortality and morbidity after restoration of spontaneous cardiac activity. The mechanisms underlying this postresuscitation disease probably involve a whole-body ischemia and reperfusion syndrome that triggers a systemic inflammatory response. RECENT FINDINGS: Postresuscitation disease is characterized by high levels of circulating cytokines and adhesion molecules, the presence of plasma endotoxin, and dysregulated leukocyte production of cytokines: a profile similar to that seen in severe sepsis. Transient myocardial dysfunction can occur after resuscitation, mainly as a result of myocardial stunning. However, early successful angioplasty is independently associated with better outcomes after cardiac arrest associated with myocardial infarction. Coagulation abnormalities occur consistently after successful resuscitation, and their severity is associated with mortality. For example, plasma protein C and S activities after successful resuscitation are lower in nonsurvivors than in survivors. Low baseline cortisol levels may be associated with an increased risk of fatal early refractory shock after cardiac arrest, suggesting adrenal dysfunction in these patients. SUMMARY: Postresuscitation abnormalities after cardiac arrest mimic the immunologic and coagulation disorders observed in severe sepsis. This suggests that therapeutic approaches used recently with success in severe sepsis should be investigated in patients successfully resuscitated after cardiac arrest.     

How do paramedics manage the airway during out of hospital cardiac arrest?

Aim

The best method of initial airway management during resuscitation for out of hospital cardiac arrest (OHCA) is unknown. The airway management techniques used currently by UK paramedics during resuscitation for OHCA are not well documented. This study describes the airway management techniques used in the usual practice arm of the REVIVE-Airways feasibility study, and documents the pathway of interventions to secure and sustain ventilation during OHCA.

Method

Data were collected from OHCAs attended by paramedics participating in the REVIVE-Airways trial between March 2012 and February 2013. Patients were included if they were enrolled in the usual practice arm of the study, fulfilled the main study eligibility criteria and did not receive either of the intervention supraglottic airway devices during the resuscitation attempt.

Results

Data from 196 attempted resuscitations were included in the analysis. The initial approach to airway management was bag-mask for 108 (55%), a supraglottic airway device (SAD) for 39 (20%) and tracheal intubation for 49 (25%). Paramedics made further airway interventions in 64% of resuscitations. When intubation was the initial approach, there was no further intervention in 76% of cases; this compares to 16% and 44% with bag-mask and SAD respectively. The most common reason cited by paramedics for changing from bag-mask was to carry out advanced life support, followed by regurgitation and inadequate ventilation. Inadequate ventilation was the commonest reason cited for removing a SAD.

Conclusion

Paramedics use a range of techniques to manage the airway during OHCA, and as the resuscitation evolves. It is therefore desirable to ensure that a range of techniques and equipment, supported by effective training, are available to paramedics who attend OHCA.     

Is scientific publishing a criminal activity?

A published scientific paper is the end-result of a complex interaction between authors, referees, editors and publishers. Each brings to the process a different agenda, and a widely disparate adherence to standards of competence and integrity. Recent internationally recognized instances of major scientific fraud represent the tip of a potentially large iceberg formed as a consequence of the ineptness or delinquency of one or other elements in the chain of surveillance designed to exercise control over the process of scientific publishing. This subjective analysis attempts to explain why and where the regulatory mechanisms that ought to detect and eliminate the publication or the dissemination by other means of poor, erroneous, or frankly fraudulent scientific finds have broken down, and what can be done to fix them.     

Managed mental health--community mental health revisited?

Despite the considerable differences between them, community and managed mental health care have much in common, particularly with regard to their values and objectives. While their differences in such things as auspice and funding may be more apparent than their commonalities, both community and managed mental health emphasize alternatives to hospitalization, continuity of care, and responsibility for a defined population. Neither managed nor community mental health care was welcomed by a mental health establishment that resisted change, although the source of the opposition was somewhat different. Inflated expectations led to disenchantment with community mental health care and could well have the same effect on managed mental health.     

Cerebral vasoconstriction in comatose patients resuscitated from a cardiac arrest?

Objective To determine the role of cerebral vasoconstriction in the delayed hypoperfusion phase in comatose patients after cardiac arrest.Design Prospective study.Setting Medical intensive care unit in a university hospital.Patients 10 comatose patients (Glasgow Coma Score 6) successfully resuscitated from a cardiac arrest occurring outside the hospital.Measurements We measured the pulsatility index (PI) and mean blood flow velocity (MFV) of the middle cerebral artery, the cerebral oxygen extraction ratio and jugular bulb levels of endothelin, nitrate, and cGMP during the first 24 h after cardiac arrest.Results The PI decreased significantly from 1.86±1.02 to 1.05±0.22 (p=0.03). The MFV increased significantly from 29±10 to 62±25 cm/s (p=0.003). Cerebral oxygen extraction ratio decreased also from 0.39±0.13 to 0.24±0.11 (p=0.015). Endothelin levels were high but did not change during the study period. Nitrate levels varied widely and showed a slight but significant decrease from 37.1 mol/l (median; 25th–75th percentiles: 26.8–61.6) to 31.3 mol/l (22.1–39.6) (p=0.04). Cyclic guanosine monophosphate levels increased significantly from 2.95 nmol/l (median; 25th–75th percentiles: 2.48–5.43) to 7.5 nmol/l (6.2–14.0) (p=0.02).Conclusions We found evidence of increased cerebrovascular resistance during the first 24 h after cardiac arrest with persistent high endothelin levels, gradually decreasing nitrate levels, and gradually increasing cGMP levels. This suggests that active cerebral vasoconstriction due to an imbalance between local vasodilators and vasoconstrictors plays a role in the delayed hypoperfusion phase.     

Exercise: a neglected intervention in mental health care?

This paper reports the results of a literature review examining the effects of exercise on mental health and well-being. Throughout history many societies, ancient and modern, have used exercise as a means of preventing disease, and promoting health and well-being. There is evidence that exercise is beneficial for mental health; it reduces anxiety, depression, and negative mood, and improves self-esteem and cognitive functioning. Exercise is also associated with improvements in the quality of life of those living with schizophrenia. However, exercise is seldom recognized by mainstream mental health services as an effective intervention in the care and treatment of mental health problems. There is evidence to suggest that exercise may be a neglected intervention in mental health care.