Miroslav Klain

Comparison of high frequency jet ventilation to conventional ventilation during severe acute respiratory failure in humans

High frequency jet ventilation (HFJV) was compared to conventional (high tidal volume, low frequency) ventilation in 9 patients with acute respiratory failure (ARF). Alveolar ventilation was comparable or lower with HFJV in all but one case. When comparisons were made at the same concentration of ox

Percutaneous transtracheal ventilation

The technique of percutaneous transtracheal ventilation (intermittent jets of oxygen under high pressure, 50 pounds per square inch [psi]) has been used for resuscitation during anesthesia and prior to tracheostomy, and has been established as an important adjunct to life-support techniques. The technical aspects are described together with experimental evidence that intermittent jet ventilation is necessary to eliminate carbon dioxide. The complications occurring with a series of 80 patients are reported along with experimental work in ventilation of dogs with compressed air sources, including truck tires. Emergency physicians should be familiar with this technique and equipment for its use should be readily available in the emergency department. The potential role of transtracheal ventilation in the mobile intensive care unit at accident sites has been explored and appears promising. Conventional airway support techniques should be applied prior to resorting to transtracheal ventilation.

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 potential of, and time limits for life-supporting first aid (LSFA), advanced trauma life support (ATLS), resuscitative surgery, 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 number of victims died slowly as the result of injuries such as external hemorrhage, head injury with coma, shock, or crush syndrome; 2) early search and rescue was performed primarily by uninjured covictims using hand tools; 3) many lives potentially 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, A TLS could have been provided in time to save lives and limbs; 5) some amputations had to be performed in the field to enable extrication; 6) the usefulness of other resuscitative surgery in the field needs 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 to impact on resuscitation. Definitive analysis of data in the near future will lead to recommendations for local, regional, and National Disaster Medical Systems (NDMS).

An experimental algorithm versus standard advanced cardiac life support in a swine model of out-of-hospital cardiac arrest

STUDY OBJECTIVE To compare an experimental algorithm with standard advanced cardiac life support in a swine model of out-of-hospital cardiac arrest. DESIGN Randomized, controlled experimental trial. SETTING/TYPE OF PARTICIPANT: Animal laboratory using swine. INTERVENTIONS Eighteen swine (17.8 to 23.7 kg) were sedated, intubated, anesthetized, and instrumented for monitoring of arterial and central venous pressures and ECG. Ventricular fibrillation was induced using a bipolar pacing catheter. Animals were randomized to treatment with the experimental algorithm or standard advanced cardiac life support therapy after eight minutes of untreated ventricular fibrillation. The experimental algorithm consisted of starting CPR; giving high-dose epinephrine (0.20 mg/kg), lidocaine (1.0 mg/kg), bretylium (5.0 mg/kg), and propranolol (0.5 to 1.0 mg) by peripheral IV; hyperventilating (20 to 25 breaths per minute); and delaying countershock (5 J/kg) 60 seconds after completion of drug delivery. Data were analyzed with the Students t-test and Fishers exact test. MEASUREMENTS AND MAIN RESULTS Outcome variables were arterial and central venous pressures, return of spontaneous circulation, and one-hour survival. Hemodynamics were not different between groups during CPR. Return of spontaneous circulation occurred in seven of nine swine (77%) in the experimental algorithm group versus two of nine swine (22%) in the advanced cardiac life support group (P = .057). Four of nine swine (44%) in the experimental algorithm group survived to one hour versus none of the animals in the advanced cardiac life support group (P = .041). CONCLUSION In this swine model of out-of-hospital cardiac arrest, animals treated with an experimental algorithm had a significant improvement in one-hour survival compared with those treated with advanced cardiac life support.

Disaster Reanimatology Potentials: A Structured Interview Study in Armenia. III. Results, Conclusions, and Recommendations

National medical responses to catastrophic disasters have failed to incorporate a resuscitation component. Purpose: This study sought to determine the lifesaving potentials of modern resuscitation medicine 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. The present article (III) reports and discusses the definitive findings, formulates conclusions, and puts forth recommendations for future responses to catastrophic disasters anywhere in the world. Results: Observations include: 1) The lack of adequate construction materials and procedures in the Armenian region contributed significantly to injury and loss of life; 2) The uninjured, lay population together with medical teams including physicians in Armenia were capable of rapid response (within two hours); 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 number of severely injured earthquake victims in Armenia died slowly without the benefit of appropriate and feasible resuscitation attempts. Recommendations: 1) Widespread adoption of seismic-resistant building codes for regions of high seismic risk; 2) The lay public living in these regions should be trained in life-supporting first-aid (LSFA) and basic rescue techniques; 3) Community-wide emergency medical services (EMS) systems should be developed world-wide (tai-lored to the emergency needs of each region) with ATLS capability for field resuscitation; 4) Such systems be prepared to extend coverage to mass casualties; 5) National disaster medical system (NDMS) plans should provide integration of existing trauma-EMS systems into regional systems linked with advanced (heavy) rescue (public works, fire, police); and 6) New techniques and devices for victim extrication should be developed to enable rapid extrication of earthquake casualties within 24 hours.

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.

Transtracheal high frequency jet ventilation prevents aspiration.

Aspiration is a potentially fatal complication of artificial ventilation. A cuffed tube is generally used now to prevent aspiration; however, it may lead to serious complications and has several disadvantages. High frequency jet ventilation (HFJV) is an innovative technique to prevent aspiration. The trachea of 6 anesthetized, paralyzed dogs was exposed and a catheter for jet ventilation introduced between the 1st and 2nd tracheal ring. Another catheter was used for measuring intratracheal pressure. An endoscope was inserted into the trachea about 2 inches lower down and directed upwards to give a view of the vocal cords from below. A mixture of saliva, saline, and cardiogreen was introduced into the mouth so as to form a pool. When observation confirmed that HFJV prevents aspiration at frequencies of 100/min and ratios of inspiration/expiration (I:E) equalling 1:1, observations were repeated at I:E, 1:2 and 1:3 and at rates of 60/min and 200/min. The depth of the pool was gradually increased to between 2 and 311 inches and observations were repeated. Endoscopy alone was used in 4 animals and endoscopic film in 2 to evaluate the efficacy of HFJV. The results showed convincingly that: (1) HFJV can prevent fluid from entering the larynx from above; (2) this effect is unreliable when the frequency is decreased to 60/min or inspiration becomes shorter than 33% of the cycle; (3) intratracheal end-expiratory pressures show values slightly higher than the fluid level above the cords; and (4) the cords are separated and the gas mixture bubbles through the fluid.We conclude that (a) valve mechanisms cannot account for our observations; and (b) at rates above 60/ min and with duration of expiration of 66% or less, HFJV will prevent aspiration by causing a continuous gas flow outward through the larynx. This is associated with a low continuous positive airway pressure and excellent blood gases.

Respiratory dialysis. A new concept in pulmonary support.

Use of a new intravenous oxygenator made of hollow fiber membranes arranged around a centrally positioned balloon is reported. In vitro studies using fluorescent image tracking velocimetry and gas exchange analysis demonstrated enhanced convective mixing with balloon pulsations and augmented gas flux (100% increase in pO2) compared with the device in its static configuration. In vivo observations confirmed a greater than 50% increase in O2 flux with balloon activation. Those parameters that produce radial flow and convective mixing in vitro enhance gas flux in vivo, thus confirming the efforts to exceed the fluid limit translate into improved gas exchange.

Reappraisal of Mouth-to-Mouth Ventilation During Bystander-Initiated CPR

To the Editor: The “reappraisal” of the literature on mouth-to-mouth ventilation during bystander-initiated CPR, by a working group of the Basic Life Support and Pediatric Life Support subcommittees of the American Heart Association (AHA),1 is misleading and incomplete. There is no convincing evidence that the low incidence of initiation of CPR out of hospital by lay bystanders is the result of fear of becoming infected by mouth-to-mouth ventilation. Such fear should not be promoted. If such fear exists, however, it should be mitigated by explaining that initiating CPR is safe and by carrying a pocket-size barrier for ventilation of strangers. The errors in this article concerning behavioral, educational, epidemiological, and logistics issues will be summarized in a separate letter by Braslow and Brennan. Although the article says “… it is not intended to change any current AHA recommendations,” its publication has created confusion and the erroneous impression for laypersons and the media that in sudden coma, bystanders will save lives by merely pushing on the sternum (step C, circulation support). In cardiac arrest, oxygenated blood must be circulated to restore heartbeat and to keep the brain viable, requiring “head tilt plus blowing plus pumping.” The article suggests that mouth-to-mouth ventilation can be omitted in various forms of sudden loss of consciousness.1 Laypersons cannot differentiate between various forms of sudden coma and between the absence versus presence of a weak pulse. Coma always results in upper airway obstruction if the neck is flexed (references 26 to 31 in the article by Becker et al),2 3 4 5 6 as experienced by anesthesiologists every day. There are 20 million general anesthesias given in the United States each year. The data in Figure 1 are misleading1 because Gordon’s measurements of 1950 (reference 24 in the article by Becker et …

Translaryngeal jet ventilation and end-tidal PCO2 monitoring during varying degrees of upper airway obstruction

STUDY OBJECTIVES To explore the ventilatory adequacy of translaryngeal jet ventilation (TLJV) during partial upper airway obstruction and the usefulness of monitoring end-tidal CO2 (PETCO2) during this condition. DESIGN Prospective, nonrandomized, sequential crossover design. SETTING AND PARTICIPANTS Apneic dog model (five dogs; mean weight, 23 kg). INTERVENTIONS Animals were intubated with a 9.0-mm endotracheal tube with the tip positioned above the cricothyroid membrane. Upper airway obstructions of 40%, 69%, and 80% were created. TLJV was performed through the cricothyroid membrane using a 13-gauge catheter with 100% oxygen, 45 psi, 15 breaths per minute, and 30% inspiratory time for 15 minutes at each upper airway obstruction. Data collected at baseline (no upper airway obstruction) and one-minute intervals included arterial blood pressures, continuous PaCO2 measurements, and PETCO2 at the TLJV catheter tip and above the level of obstruction. Arterial blood gases were obtained at 0 and 15 minutes. Data were analyzed using Pearsons correlation, analysis of variance, and Turkeys multiple comparisons (significance, P less than .05). MEASUREMENTS AND RESULTS Baseline values for all variables did not significantly differ at the onset of each testing phase. Mean pH increased significantly from baseline during 69% upper airway obstruction (7.36 to 7.54, P less than .05) and 80% upper airway obstruction (7.39 to 7.61, P less than .01). Mean PaCO2 decreased significantly from baseline during all upper airway obstructions: 40% upper airway obstruction (39.9 to 33.6 mm Hg, P less than .01), 69% upper airway obstruction (38.3 to 25.6 mm Hg, P less than .001), and 80% upper airway obstruction (36.2 to 18.2 mm Hg, P less than .001). PaCO2, PETCO2, and pH differed significantly between each level of upper airway obstruction (P less than .01). PETCO2 was significantly correlated with PaCO2 (r = .84, P less than .001) and did not significantly differ from PaCO2. No signs of barotrauma were observed in any animal at any degree of upper airway obstruction. CONCLUSION TLJV during partial upper airway obstruction in our model provided safe and adequate-to-supranormal minute ventilation. In fact, marked hypocapnia and alkalemia occurred at levels of 69% and 80% upper airway obstruction, thus dispelling concepts that TLJV may cause hypercapnia during partial upper airway obstruction. PETCO2 correlates well with PaCO2 and may be valuable for monitoring ventilation when using TLJV in the nonobstructed or partially obstructed upper airway.