Jakob Johansson

Increased cortical cerebral blood flow by continuous infusion of adrenaline (epinephrine) during experimental cardiopulmonary resuscitation

OBJECTIVE To study the effects of continuously administered adrenaline (epinephrine), compared to bolus doses, on the dynamics of cortical cerebral blood flow during experimental cardiopulmonary resuscitation (CPR), and after restoration of spontaneous circulation (ROSC). METHODS Ventricular fibrillation was induced in 24 anaesthetised pigs. After a 5-min non-intervention interval, closed-chest CPR was started. The animals were randomised into two groups. One group received three boluses of adrenaline (20 microg/kg) at 3-min intervals. The other group received an initial bolus of adrenaline (20 microg/kg) followed by an infusion of adrenaline (10 microg/kg x min). After 9 min of CPR, defibrillation was attempted, and if spontaneous circulation was achieved the adrenaline infusion was stopped. Cortical cerebral blood flow was measured continuously using Laser-Doppler flowmetry. Jugular bulb oxygen saturation was measured to reflect global cerebral oxygenation. Repeated measurements of 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) in jugular bulb plasma were performed to evaluate cerebral oxidative injury. RESULTS During CPR mean cortical cerebral blood flow was significantly higher (P=0.009) with a continuous adrenaline infusion than with repeated bolus doses. Following ROSC there was no significant difference in cortical cerebral blood flow between the two study groups. No differences in coronary perfusion pressure, rate of ROSC, jugular bulb oxygen saturation or 8-iso-PGF(2alpha) were seen between the study groups. CONCLUSIONS Continuous infusion of adrenaline (10 microg/kg x min) generated a more sustained increase in cortical cerebral blood flow during CPR as compared to intermittent bolus doses (20 microg/kg every third minute). Thus, continuous infusion might be a more appropriate way to administer adrenaline as compared to bolus doses during CPR.

Clinical teaching improvement: The transportability of the Stanford Faculty Development Program.

Background: The Stanford Faculty Development Center (SFDC) at Stanford University developed a teaching improvement course for medical teachers that has been widely disseminated using a train-the-trainer model. We were curious to see if cultural factors might influence the applicability and impact of the course when delivered to non-American participants by a facilitator from that culture. Methods: A Swedish anaesthesiologist at Uppsala University Hospital, Sweden, was trained in October 2004 at Stanford University. From January 2005 to March 2007 he delivered five faculty development seminar series at Uppsala University Hospital to 40 physicians from different departments. Participants rated the usefulness of the seminar series and retrospective pre- and post-seminar ratings were used to assess effects on participants’ teaching skills and behaviours. Results: Participants rated the seminars as highly useful (M = 4.8, SD = 0.4). Participants’ ratings of their teaching ability indicated significant increases across a variety of clinical and non-clinical teaching settings (p < 0.001), and positive changes in teaching behaviours were found for all seven educational categories assessed (p < 0.001). Conclusions: This faculty development model is highly transportable to medical teachers in Sweden, and capable of producing positive results, consistent with those found in the United States.

Adrenaline administration during cardiopulmonary resuscitation: poor adherence to clinical guidelines

Background:  Adrenaline does not appear to improve the outcome after cardiac arrest in clinical trials in spite of beneficial effects in experimental studies. The objective of this study was to determine whether adrenaline was administered in accordance with advanced cardiac life support (ACLS) guidelines during adult cardiopulmonary resuscitation (CPR).

A randomised controlled study of role play in a faculty development programme.

Background: The Stanford Faculty Development Center at Stanford University has developed a teaching improvement course for medical teachers that has been widely disseminated using a train-the-trainer model. Aims: This study was designed to investigate the relative impact of role playing as an instructional technique within that course for facilitating change in teaching behaviours. Method: From January 2009 to April 2010, six faculty development courses were delivered at Uppsala University Hospital to 48 physicians from different departments. The standard course presentation includes a range of instructional methods including short lectures, small group discussion, review of video re-enactments, role-play exercises and personal goal setting. For this study, participants were randomised to participate in (1) a ‘standard’ course with role play or (2) an ‘alternative’ course with no role play. The effects of the course on teaching performance were assessed with retrospective pre- and post-course self-ratings of 29 specific teaching behaviours. Results: Self-assessment ratings indicated significantly greater positive changes in teaching behaviour among faculty who attended the standard course (with role play) as compared to those in the alternative course (p = 0.015). Conclusions: This study validates the commonly held view that role play is a useful instructional method for improving teaching.

A modified Glenn shunt improves haemodynamics in acute right ventricular failure in an experimental model

OBJECTIVES Right heart failure is a major cause of morbidity and mortality after left ventricular assist device implantation and is still hard to predict. This study investigated the haemodynamic effect of a modified Glenn shunt on induced right ventricular (RV) failure. METHODS Isolated RV failure was induced by coronary ligation in 11 pigs. A modified Glenn shunt was established by a superior vena cava to pulmonary artery connection. Haemodynamic data were obtained at baseline, RV failure, and RV failure and open shunt. Myocardial biopsies were taken to ascertain established heart failure. RESULTS RV failure defined as right atrial pressure ≥20 mmHg was achieved in all 11 animals. A reduction in cardiac output (CO) from 3.7 (3.5-4.2) to 2.3 l/min (2.0-2.6) and mean arterial pressure (MAP) from median 72.7 (70.1-82.2) to 55.9 mmHg (52.6-59.8) was seen during heart failure. The median flow in the shunt was 681 ml. Right atrial pressures decreased from 20.3 (19.6-21.1) to 13.4 mmHg (12.7-14.0), and RV pressures decreased from 18.1 (16.4-20.1) to 13.6 mmHg (13.5-14.2) with open shunt (P = 0.001 for both). CO increased to 2.9 l/min (2.4-3.3) when the shunt was in use. Mixed venous oxygen saturation increased with the shunt from 32 (27-38) to 49% (45-56), P = 0.001. Genes associated with heart failure were upregulated during heart failure. CONCLUSIONS A modified Glenn shunt improved haemodynamics by reduced right atrial pressure, increased CO, MAP and mixed venous oxygen saturation in an experimental model of induced RV failure.

Antithrombin reduction after experimental cardiopulmonary resuscitation

OBJECTIVE To determine whether activation of coagulation and inflammation during cardiac arrest results in a reduction of antithrombin (AT) and an increase in thrombin-antithrombin (TAT) complex during reperfusion. METHODS Ventricular fibrillation (VF) was induced in ten anaesthetized pigs. After a 5-min non-intervention interval, closed-chest cardiopulmonary resuscitation (CPR) was performed for 9 min before defibrillation was attempted. If restoration of spontaneous circulation (ROSC) was achieved, the animals were observed for 4 h and repeated blood samples were taken for assay of AT, TAT and eicosanoids (8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha)). RESULTS AT began to decrease 15 min after ROSC and the reduction continued throughout the observation period (P<0.05). The lowest mean value (79%) occurred 60 min after ROSC. The TAT level was increased during the first 3 h after ROSC (P<0.05), indicating thrombin generation. The eicosanoids were increased throughout the observation period (P<0.05). CONCLUSIONS AT is reduced and TAT and eicosanoids are increased after cardiac arrest, indicating activation of coagulation and inflammation.

Cavoaortic shunt improves hemodynamics with preserved oxygen delivery in experimental right ventricular failure during left ventricular assist device therapy

OBJECTIVE Right heart failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. This study evaluated the approach of a cavoaortic shunt included in the LVAD circuit, which would aim to relieve venous congestion and improve hemodynamics with preserved oxygen delivery during induced right ventricular failure. METHODS Right ventricular failure was induced by coronary ligation in 10 pigs. An LVAD was implanted and a cavoaortic shunt was created from the right atrium and included in the assist circuit. Hemodynamic measures and blood gas analyses were analyzed. Oxygen delivery and oxygen consumption were estimated. RESULTS Right atrial pressure decreased from more than 20 mm Hg to 17.2 mm Hg (14.8-18.4) with the LVAD and to 14.1 mm Hg (11.2-15.5) (P < .01) with the LVAD and cavoaortic shunt. Mean arterial pressure increased from 70.9 mm Hg (67.6-79.8) to 81.5 mm Hg (70.8-92.6) (P = .02) with addition of the shunt into the assist circuit. Cardiac output increased from 3.5 L/min (2.6-4.2) to 4.9 L/min (3.5-5.6) (P < .01) with cavoaortic shunting. Oxygen delivery with the cavoaortic shunt was 337 mL/min (± 70) as compared with left ventricular assist alone at 258 mL/min (± 52) (P < .01). Oxygen consumption was restored during use of the cavoaortic shunt. CONCLUSIONS A cavoaortic shunt combined with an LVAD during right ventricular failure reduces central venous pressures, increases systemic arterial pressure, and enables increased cardiac output compared with device therapy alone. This was feasible with preserved oxygen delivery.

Agreement between ambulance nurses and physicians in assessing stroke patients.

If an ambulance nurse could bypass the emergency department (ED) and bring suspected stroke patients directly to a CT scanner, time to thrombolysis could be shortened. This study evaluates the level of agreement between ambulance nurses and emergency physicians in assessing the need for a CT scan, and interventions and monitoring beforehand, in patients with suspected stroke and/or a lowered level of consciousness.