Jon-Kenneth Heltne

Factors complicating interpretation of capnography during advanced life support in cardiac arrest—A clinical retrospective study in 575 patients

BACKGROUND End tidal carbon dioxide (ETCO(2)) monitoring during advanced life support (ALS) using capnography, is recommended in the latest international guidelines. However, several factors might complicate capnography interpretation during ALS. How the cause of cardiac arrest, initial rhythm, bystander cardiopulmonary resuscitation (CPR) and time impact on the ETCO(2) values are not completely clear. Thus, we wanted to explore this in out-of-hospital cardiac arrested (OHCA) patients. METHODS The study was carried out by the Emergency Medical Service of Haukeland University Hospital, Bergen, Norway. All non-traumatic OHCAs treated by our service between January 2004 and December 2009 were included. Capnography was routinely used in the study, and these data were retrospectively reviewed together with Utstein data and other clinical information. RESULTS Our service treated 918 OHCA patients, and capnography data were present in 575 patients. Capnography distinguished well between patients with or without return of spontaneous circulation (ROSC) for any initial rhythm and cause of the arrest (p<0.001). Cardiac arrests with a respiratory cause had significantly higher levels of ETCO(2) compared to primary cardiac causes (p<0.001). Bystander CPR affected ETCO(2)-recordings, and the ETCO(2) levels declined with time. CONCLUSIONS Capnography is a useful tool to optimise and individualise ALS in cardiac arrested patients. Confounding factors including cause of cardiac arrest, initial rhythm, bystander CPR and time from cardiac arrest until quantitative capnography had an impact on the ETCO(2) values, thereby complicating and limiting prognostic interpretation of capnography during ALS.

Factors predicting the use of therapeutic hypothermia and survival in unconscious out-of-hospital cardiac arrest patients admitted to the ICU

IntroductionTherapeutic hypothermia (TH) after out-of-hospital cardiac arrest (OHCA) was adopted early in Norway. Since 2004 the general recommendation has been to cool all unconscious OHCA patients treated in the intensive care unit (ICU), but the decision to cool individual patients was left to the responsible physician. We assessed factors that were associated with use of TH and predicted survival.MethodWe conducted a retrospective observational study of prospectively collected cardiac arrest and ICU registry data from 2004 to 2008 at three university hospitals.ResultsA total of 715 unconscious patients older than 18 years of age, who suffered OHCA of both cardiac and non-cardiac causes, were included. With an overall TH use of 70%, the survival to discharge was 42%, with 90% of the survivors having a favourable cerebral outcome. Known positive prognostic factors such as witnessed arrest, bystander cardio pulmonary resuscitation (CPR), shockable rhythm and cardiac origin were all positive predictors of TH use and survival. On the other side, increasing age predicted a lower utilisation of TH: Odds Ratio (OR), 0.96 (95% CI, 0.94 to 0.97); as well as a lower survival: OR 0.96 (95% CI, 0.94 to 0.97). Female gender was also associated with a lower use of TH: OR 0.65 (95% CI, 0.43 to 0.97); and a poorer survival: OR 0.57 (95% CI, 0.36 to 0.92). After correcting for other prognostic factors, use of TH remained an independent predictor of improved survival with OR 1.91 (95% CI 1.18-3.06; P <0.001). Analysing subgroups divided after initial rhythm, these effects remained unchanged for patients with shockable rhythm, but not for patients with non-shockable rhythm where use of TH and female gender lost their predictive value.ConclusionsAlthough TH was used in the majority of unconscious OHCA patients admitted to the ICU, actual use varied significantly between subgroups. Increasing age predicted both a decreased utilisation of TH as well as lower survival. Further, in patients with a shockable rhythm female gender predicted both a lower use of TH and poorer survival. Our results indicate an underutilisation of TH in some subgroups. Hence, more research on factors affecting TH use and the associated outcomes in subgroups of post-resuscitation patients is needed.

Emergency intraosseous access in a helicopter emergency medical service: a retrospective study

BackgroundIntraosseous access (IO) is a method for providing vascular access in out-of-hospital resuscitation of critically ill and injured patients when traditional intravenous access is difficult or impossible. Different intraosseous techniques have been used by our Helicopter Emergency Medical Services (HEMS) since 2003. Few articles document IO use by HEMS physicians. The aim of this study was to evaluate the use of intraosseous access in pre-hospital emergency situations handled by our HEMS.MethodsWe reviewed all medical records from the period May 2003 to April 2010, and compared three different techniques: Bone Injection Gun (B.I.G® - Waismed), manual bone marrow aspiration needle (Inter V - Medical Device Technologies) and EZ-IO® (Vidacare), used on both adults and paediatric patients.ResultsDuring this seven-year period, 78 insertion attempts were made on 70 patients. Overall success rates were 50% using the manual needle, 55% using the Bone Injection Gun, and 96% using the EZ-IO®. Rates of success on first attempt were significantly higher using the EZ-IO® compared to the manual needle/Bone Injection Gun (p < 0.01/p < 0.001). Fifteen failures were due to insertion-related problems (19.2%), with four technical problems (5.1%) and three extravasations (3.8%) being the most frequent causes. Intraosseous access was primarily used in connection with 53 patients in cardiac arrest (75.7%), including traumatic arrest, drowning and SIDS. Other diagnoses were seven patients with multi-trauma (10.0%), five with seizures/epilepsy (7.1%), three with respiratory failure (4.3%) and two others (2.9%). Nearly one third of all insertions (n = 22) were made in patients younger than two years. No cases of osteomyelitis or other serious complications were documented on the follow-up.ConclusionsNewer intraosseous techniques may enable faster and more reliable vascular access, and this can lower the threshold for intraosseous access on both adult and paediatric patients in critical situations. We believe that all emergency services that handle critically ill or injured paediatric and adult patients should be familiar with intraosseous techniques.

Dynamic evaluation of fluid shifts during normothermic and hypothermic cardiopulmonary bypass in piglets

Background: Edema, generalized overhydration and organ dysfunction commonly occur in patients undergoing open‐heart surgery using cardiopulmonary bypass (CPB) and induced hypothermia. Activation of inflammatory reactions induced by contact between blood and foreign surfaces are commonly held responsible for the disturbances of fluid balance (“capillary leak syndrome”). We used an online technique to determine fluid shifts between the intravascular and the interstitial space during normothermic and hypothermic CPB.

Laryngeal tube use in out-of-hospital cardiac arrest by paramedics in Norway

BackgroundAlthough there are numerous supraglottic airway alternatives to endotracheal intubation, it remains unclear which airway technique is optimal for use in prehospital cardiac arrests. We evaluated the use of the laryngeal tube (LT) as an airway management tool among adult out-of-hospital cardiac arrest (OHCA) patients treated by our ambulance services in the Haukeland and Innlandet hospital districts.MethodsPost-resuscitation forms and data concerning airway management in 347 adult OHCA victims were retrospectively assessed with regard to LT insertion success rates, ease and speed of insertion and insertion-related problems.ResultsA total of 402 insertions were performed on 347 OHCA patients. Overall, LT insertion was successful in 85.3% of the patients, with a 74.4% first-attempt success rate. In the minority of patients (n = 46, 13.3%), the LT insertion time exceeded 30 seconds. Insertion-related problems were recorded in 52.7% of the patients. Lack of respiratory sounds on auscultation (n = 100, 28.8%), problematic initial tube positioning (n = 85, 24.5%), air leakage (n = 61, 17.6%), vomitus/aspiration (n = 44, 12.7%), and tube dislocation (n = 17, 4.9%) were the most common problems reported. Insertion difficulty was graded and documented for 95.4% of the patients, with the majority of insertions assessed as being “Easy” (62.5%) or “Intermediate” (24.8%). Only 8.1% of the insertions were considered to be “Difficult”.ConclusionsWe found a high number of insertion related problems, indicating that supraglottic airway devices offering promising results in manikin studies may be less reliable in real-life resuscitations. Still, we consider the laryngeal tube to be an important alternative for airway management in prehospital cardiac arrest victims.

Studies on fluid extravasation related to induced hypothermia during cardiopulmonary bypass in piglets.

Background: Hypothermia, commonly used for organ protection during cardiopulmonary bypass (CPB), has been associated with changes in plasma volume, hemoconcentration and microvascular fluid shifts. Fluid pathophysiology secondary to hypothermia and the mechanisms behind these changes are still largely unknown. In a recent study we found increased fluid needs during hypothermic compared to normothermic CPB. The aim of the present study was to characterize the distribution of the fluid given to maintain normovolemia. In addition, we wanted to investigate the quantity and quality of the fluid extravasated during hypothermic compared to normothermic CPB.

Can the use of methylprednisolone, vitamin C, or α-trinositol prevent cold-induced fluid extravasation during cardiopulmonary bypass in piglets?

OBJECTIVE Hypothermic cardiopulmonary bypass is associated with capillary fluid leakage, resulting in edema and occasionally organ dysfunction. Systemic inflammatory activation is considered responsible. In some studies methylprednisolone has reduced the weight gain during cardiopulmonary bypass. Vitamin C and alpha-trinositol have been demonstrated to reduce the microvascular fluid and protein leakage in thermal injuries. We therefore tested these three agents for the reduction of cold-induced fluid extravasation during cardiopulmonary bypass. METHODS A total of 28 piglets were randomly assigned to four groups of 7 each: control group, high-dose vitamin C group, methylprednisolone group, and alpha-trinositol-group. After 1 hour of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass was initiated in all animals and continued to 90 minutes. The fluid level in the extracorporeal circuit reservoir was kept constant at the 400-mL level and used as a fluid gauge. Fluid needs, plasma volume, changes in colloid osmotic pressure in plasma and interstitial fluid, hematocrit, and total water contents in different tissues were recorded, and the protein masses and the fluid extravasation rate were calculated. RESULTS Hemodilution was about 25% after start of normothermic cardiopulmonary bypass. Cooling did not cause any further changes in hemodilution. During steady-state normothermic cardiopulmonary bypass, the fluid need in all groups was about 0.10 mL/(kg.min), with a 9-fold increase during the first 30 minutes of cooling (P <.001). This increased fluid need was due mainly to increased fluid extravasation from the intravascular to the interstitial space at a mean rate of 0.6 mL/(kg.min) (range 0.5-0.7 mL/[kg.min]; P <.01) and was reflected by increased total water content in most tissues in all groups. The albumin and protein masses remained constant in all groups throughout the study. CONCLUSION Pretreatment with methylprednisolone, vitamin C, or alpha-trinositol was unable to prevent the increased fluid extravasation rate during hypothermic cardiopulmonary bypass. These findings, together with the stability of the protein masses throughout the study, support the presence of a noninflammatory mechanism behind the cold-induced fluid leakage seen during cardiopulmonary bypass.

Determination of plasma volume in anaesthetized piglets using the carbon monoxide (CO) method

Based on measurements of the circulating red blood cell volume (VRBC) in seven anaesthetized piglets using carbon monoxide (CO) as a label, plasma volume (PV) was calculated for each animal. The increase in carboxyhaemoglobin (COHb) concentration following administration of a known amount of CO into a closed circuit re-breathing system was determined by diode-array spectrophotometry. Simultaneously measured haematocrit (HCT) and haemoglobin (Hb) values were used for PV calculation. The PV values were compared with simultaneously measured PVs determined using the Evans blue technique. Mean values (SD) for PV were 1708.6 (287.3)ml and 1738.7 (412.4)ml with the CO method and the Evans blue technique, respectively. Comparison of PVs determined with the two techniques demonstrated good correlation (r = 0.995). The mean difference between PV measurements was -29.9 ml and the limits of agreement (mean difference ±2SD) were -289.1 ml and 229.3 ml. In conclusion, the CO method can be applied easily under general anaesthesia and controlled ventilation with a simple administration system. The agreement between the compared methods was satisfactory. Plasma volume determined with the CO method is safe, accurate and has no signs of major side effects.

Pre-hospital advanced airway management by anaesthesiologists: is there still room for improvement?

BackgroundEndotracheal intubation is an important part of pre-hospital advanced life support that requires training and experience, and should only be performed by specially trained personnel. In Norway, anaesthesiologists serve as Helicopter Emergency Medical Service HEMS physicians. However, little is known about how they themselves evaluate the quality and safety of pre-hospital advanced airway management.MethodUsing a semi-structured questionnaire, we interviewed anaesthesiologists working in the three HEMS programs covering Western Norway. We compared answers from specialists and non-specialists as well as full- and part-time HEMS physicians.ResultsOf the 17 available respondents, most (88%) felt that their continuous exposure to intubations was not sufficient. Additional training was mainly acquired through other clinical practice and mannequin- or cadaver-based skills training. Of the respondents, 77% and 35% reported having experienced difficult and failed intubations, respectively. Further, 59% reported knowledge of airway management-related deaths in their HEMS program. Significantly more full- than part-time HEMS physicians had experienced these problems. All respondents had airway back-up equipment in their service, but 29% were not familiar with all the equipment.ConclusionThe majority of anaesthesiologists working as HEMS physicians view pre-hospital advanced airway management as a high-risk procedure. Relevant airway management competencies for HEMS physicians in Norway seem to be insufficiently trained and maintained. A better-defined level of competence with better training methods and systems seems warranted.

Freeze dried plasma and fresh red blood cells for civilian prehospital hemorrhagic shock resuscitation.

BACKGROUND The last decade of military trauma care has emphasized the role of blood products in the resuscitation of hemorrhaging patients. Damage-control resuscitation advocates decreased crystalloid use and reintroduces blood components as primary resuscitative fluids. The systematic use of blood products have been described in military settings, but reports describing the use of freeze dried plasma (FDP) or red blood cells (RBCs) in civilian prehospital care are few. We describe our preliminary results after implementing RBCs and FDP into our Helicopter Emergency Medical Service (HEMS). METHODS We collected data on the use of FDP (LyoPlas N–w (AB)) during a 12-month period from May 31, 2013, to May 30, 2014, before RBC (0Rh (D) negative) introduction in June 2014. FDP and RBCs were indicated in trauma and medical patients presenting with clinical significant hemorrhage on scene. Data were obtained from HEMS registry and patient records. RESULTS Our preliminary results show that FDP was used in 16 patients (88% males) during the first year. Main patient categories were blunt trauma (n = 5), penetrating trauma (n = 4), and nontrauma (n = 7). Ten patients (62%) were hypotensive with systolic blood pressures less than 90 mm Hg on scene. The majority (75%) received tranexamic acid. Of 14 patients admitted to the hospital, 11 received emergency surgery and 8 needed additional transfusions within the first 24 hours. No transfusion-related complications were recorded. Two of the FDP patients died on scene, and the remaining 14 patients were alive after 30 days. Early results from the recent introduction of RBC show that RBCs were given to four patients. Two patients (one penetrating trauma and one blunt trauma patient) died on scene because of exsanguination, while additional two patients (one blunt trauma patient and one with ruptured aortic aneurism) survived to hospital discharge. CONCLUSION Our small study indicates that introduction of FDP into civilian HEMS seems feasible and may be safe and that logistical and safety issues for the implementation of RBCs are solvable. FDP ensures both coagulation factors and volume replacement, has a potentially favorable safety profile, and may be superior to other types of plasma for prehospital use. Further prospective studies are needed to clarify the role of FDP (and RBCs) in civilian prehospital hemorrhagic shock resuscitation and to aid the development of standardized protocols for prehospital use of blood products. LEVEL OF EVIDENCE Therapeutic study, level V.