High-frequency jet ventilation: utility in posterior left atrial catheter ablation.

BACKGROUND: Percutaneous catheter ablation in the posterior left atrium (LA) is a technically demanding procedure that in our experience is best accomplished using general anesthesia, including endotracheal intubation and mechanical ventilation. However, using conventional intermittent positive-pressure ventilation (IPPV) technique, we were dissatisfied with motion of the posterior LA. This occurred during changes in lung volume, which destabilized ablation electrode-endocardial contact. We hypothesized that use of high-frequency jet ventilation (HFJV), a low-volume, fast-rate technique, would reduce posterior LA motion and thus facilitate the ablation procedure. OBJECTIVES: The purpose of this study was to demonstrate that, relative to IPPV, HFJV reduces posterior LA motion and facilitates catheter ablation in this region. METHODS: Patients who underwent posterior LA ablation using HFJV (n = 36) were retrospectively compared with those in whom IPPV (n = 36) was used. Indices examined included number of radiofrequency energy applications, electrode temperature, and procedure time. A prospective direct comparison of the impact of HFJV and IPPV on LA volume and mechanical function was performed in an additional 10 patients. RESULTS: Fewer ablation lesions were required in the HFJV group because of fewer incidences of ablation electrode dislodgment, resulting in significantly decreased procedure time. Although there was no significant difference in maximal electrode temperature achieved during radiofrequency application, temperature variation was diminished in the HFJV group. Direct comparison demonstrated that HFJV produced less variation in LA volume, pressure, pulmonary vein blood flow velocity, and posterior LA position than IPPV. CONCLUSION: Relative to IPPV, HFJV yields a more stable posterior LA environment, thus facilitating catheter ablation. Use of HFJV may be applicable to other interventional cardiovascular procedures.

Suspended animation can allow survival without brain damage after traumatic exsanguination cardiac arrest of 60 minutes in dogs.

BACKGROUND: We have previously shown in dogs that exsanguination cardiac arrest of up to 120 minutes without trauma under profound hypothermia induced by aortic flush (suspended animation) can be survived without neurologic deficit. In the present study, the effects of major trauma (laparotomy, thoracotomy) are explored. This study is designed to better mimic the clinical scenario of an exsanguinating trauma victim, for whom suspended animation may buy time for resuscitative surgery and delayed resuscitation. METHODS: Fourteen dogs were exsanguinated over 5 minutes to cardiac arrest. Flush of saline at 2 degrees C into the femoral artery was initiated at 2 minutes of cardiac arrest and continued until a tympanic temperature of 10 degrees C was achieved. The dogs were then randomized into a control group without trauma (n = 6) or a trauma group (n = 8) that underwent a laparotomy and isolation of the spleen before hemorrhage and then, at the start of cardiac arrest, spleen transection and left thoracotomy. During cardiac arrest, splenectomy was performed. After 60 minutes of no-flow cardiac arrest, reperfusion with cardiopulmonary bypass was followed by intensive care to 72 hours. RESULTS: All 14 dogs survived to 72 hours with histologically normal brains. All control dogs were functionally neurologically intact. Four of eight trauma dogs were also functionally normal. Four had neurologic deficits, although three required prolonged mechanical ventilation because of airway edema and evidence of multiple organ failure. Blood loss from the chest and abdomen was variable and was associated with poor functional outcomes. CONCLUSION: Rapid induction of profound hypothermic suspended animation (tympanic temperature, 10 degrees C) can enable survival without brain damage after exsanguination cardiac arrest of 60 minutes even in the presence of trauma, although prolonged intensive care may be required. This technique may allow survival of exsanguinated trauma victims, who now have almost no chance of survival.

Disater reanimatology potentials : A structured interview study in Armenia. III. Results, conclusions, and recommendations

Nacional medical responses to catastrophic disasters have failed to incorporate a resuscitation component. Purpose: This study sought to determine the lifesaving potentials of modern resuscitation medicin as applied to a catastrophic disaster situation. Previous articles reported the preliminary results(I) and methodology (II)of a structured, retrospective interview study of the 1988 earthquake in Armenia.(III) reports and discuses the definitive findings formulates conclusions. Results: Observations include: 1)The lack of adequate construction materials and procedures in the Armenian region contributed significantly to injury and loss life 2) The uninjured lay population together with medical teams including physician in Armenia were capable of rapid response 3) Due to a lack of Advanced Trauma Life Support (ATLS) training for medical teams and of basic first-aid training of the lay public and scarcity of supplies and equipment for extrication of casualties, they were unable to do much at the scene. As a result, an undetermined nnumber of severely injured earthquake victims in Armenia died slowly without the benefit of appropriate and feasible resuscitation(AU)

Disaster reanimatology potentials : A structural interview study in Armenia

The study of a disaster which has accurred cannot using the traditional techniques as it is not possible to conceive or conduct controlled, randomized experiments for such an event. Paper I of this series described non-experimental, scientific methodologies which were applied to study the detection-extrication-resucitatioj activities which occurred following the devastating 1988 earthquake in the Republic of Armenia, USSR. This paper critically evaluates the methodologies used for the Armenia study and proposes modification in these methods for application to the study of future disasters.(AU)

Disaster reanimatology potentials : A structured interview study in Armenia : I. Methodology and preliminary results

In general preparations for disasters which result in mass casualties do not incorporate a modern resuscitation approach. WE explored the life-saving potencial of and time limits for life-supporting first aid (LSFA), advanced trauma life support (ATLS) resuscitative surgery, and prolonged life support, Following the earthquake in Armenia on 7 december 1988. We used a structured retrospective interview method applied previously to evaluation of emergency medical services (EMS) in the United States. A total of 120 survivors of and participants in the earthquake in Armenia were interviewed on site (49 lay eyewitnesses, 20 search-search-rescue personnel, 39 medical personnel and records and 12 administrators).

Disaster reanimatology potentials : A structural interview study in Armenia : I. Methodology and preliminary results

In general, preparations for disasters which results in mass casualties do not incorporate a modern resuscitation approach. We explored the life-saving potential of, and time limits for life-supporting first aid (LSFA), advanced trauma life support (ATLS), resuscitative surgey, and prolonged life support (PLS: intensive care) following the earthquake in Armenia on 7 December 1988. We used a structured, retrospective interview method applied previously to evaluation of emergency medical services (EMS) in the United States. A total of 120 survivors of, and participants in the earthquake in Armenia were interviewed on site (49 lay eyewitnesses, 20 search-rescue personnel, 39 medical personnel and records, and 12 administrators). Answers were verified by crosschecks.Preliminary results permit the following generalizations: 1)a significant nomber of victims died slowly as the result of iinjuries such as external hemorrhage, head injury with coma,shock, or crush sundrome; 2) early search and rescue was perfomed primarily by uninjured covictims using hand tools; 3) many livespotentially could have been saved by the use of LSFA and ATLS started during extrication of crushed victims. 4) medical teams from neighboring EMS systems started to arrive at the site at 2-3 hours and therefore, ATLS could have been provided in time to save lives and limbs; 5) some amputations had to be perfomed in the field to enable extrication; 6) the usefulness of other resuscitative surgery in the fieldneeds to be clarified; 7) evacuations were rapid; 8) air evacuation proved essential; 9) hospital intensive care was well organized; and 10)international medical aid, which arrived after 48 hours, was too late top impact on resuscitation. definitive analysis of data in the near future will lead to recommendations for local, regional, and National Disaster Medical Systems (NDMS).(AU)