Karel Habig

Apneic Oxygenation Was Associated With Decreased Desaturation Rates During Rapid Sequence Intubation by an Australian Helicopter Emergency Medicine Service

STUDY OBJECTIVE The Greater Sydney Area Helicopter Emergency Medical Service undertakes in excess of 2,500 physician/paramedic out-of-hospital and interhospital retrievals each year, of which 8% require intubation. Emergency anesthesia of critically ill patients is associated with complications, including hypoxia. In July 2011, the service introduced apneic oxygenation with nasal cannulae to its emergency anesthesia standard operating procedure to reduce rates of desaturation during rapid sequence intubation. We evaluate the association between the introduction of apneic oxygenation and incidence of desaturation during rapid sequence intubation in both out-of-hospital and interhospital retrievals. METHODS This was a retrospective study of prospectively collected airway registry data. Consecutive patients who underwent rapid sequence intubation by Greater Sydney Area Helicopter Emergency Medical Service personnel between September 2009 and July 2013, spanning the introduction of apneic oxygenation, were included for analysis (n=728). We compared patients who underwent rapid sequence intubation before the service introduced apneic oxygenation (n=310) with those who underwent it after its introduction (n=418). We evaluated the association between the introduction of apneic oxygenation and the incidence of desaturation. RESULTS During the study period, 9,901 missions were conducted with 728 rapid sequence intubations (310 pre- and 418 postapneic oxygenation). The introduction of apneic oxygenation was followed by a decrease in desaturation rates from 22.6% to 16.5% (difference=6.1%; 95% confidence interval 0.2% to 11.2%). CONCLUSION Introduction of apneic oxygenation was associated with decreased incidence of desaturation in patients undergoing rapid sequence intubation.

Algorithm for the resuscitation of traumatic cardiac arrest patients in a physician-staffed helicopter emergency medical service

Survival rates following traumatic cardiac arrest (TCA) are known to be poor but resuscitation is not universally futile. There are a number of potentially reversible causes to TCA and a well-defined group of survivors. There are distinct differences in the pathophysiology between medical cardiac arrests and TCA. The authors present some of the key differences and evidence related to resuscitation in TCA, and suggest a separate algorithm for the management of out-of-hospital TCA attended by a highly trained physician and paramedic team.See related commentary by Klein, http://ccforum.com/content/17/3/156

Are physicians required during winch rescue missions in an Australian helicopter emergency medical service

Background A helicopter emergency medical service (HEMS) capable of winching offers several advantages over standard rescue operations. Little is known about the benefit of physician winching in addition to a highly trained paramedic. Objective To analyse the mission profiles and interventions performed during rescues involving the winching of a physician in the Greater Sydney Area HEMS (GSA-HEMS). Methods All winch missions involving a physician from August 2009 to January 2012 were identified from the prospectively completed GSA-HEMS electronic database. A structured case sheet review for a predetermined list of demographic data and physician-only interventions (POIs) was conducted. Results We identified 130 missions involving the winching of a physician, of which 120 case sheets were available for analysis. The majority of patients were traumatically injured (90%) and male (85%) with a median age of 37 years. Seven patients were pronounced dead at the scene. A total of 63 POIs were performed on 48 patients. Administration of advanced analgesia was the most common POI making up 68.3% of interventions. Patients with abnormal RTSc2 scores were more likely to receive a POI than those with normal RTSc2 (84.8% vs 15.2%; p=0.03). The performance of a POI had no effect on median scene times (45 vs 43 min; p=0.51). Conclusions Our high POI rate of 40% (48/120) coupled with long rescue times and the occasional severe injuries support the argument for winching Physicians. Not doing so would deny a significant proportion of patients time-critical interventions, advanced analgesia and procedural sedation.

Sustained life-like waveform capnography after human cadaveric tracheal intubation

Introduction Fresh frozen cadavers are effective training models for airway management. We hypothesised that residual carbon dioxide (CO2) in cadaveric lung would be detectable using standard clinical monitoring systems, facilitating detection of tracheal tube placement and further enhancing the fidelity of clinical simulation using a cadaveric model. Methods The tracheas of two fresh frozen unembalmed cadavers were intubated via direct laryngoscopy. Each tracheal tube was connected to a self-inflating bag and a sidestream CO2 detector. The capnograph display was observed and recorded in high-definition video. The cadavers were hand-ventilated with room air until the capnometer reached zero or the waveform approached baseline. Results A clear capnographic waveform was produced in both cadavers on the first postintubation expiration, simulating the appearances found in the clinical setting. In cadaver one, a consistent capnographic waveform was produced lasting over 100 s. Maximal end-tidal CO2 was 8.5 kPa (65 mm Hg). In cadaver two, a consistent capnographic waveform was produced lasting over 50 s. Maximal end-tidal CO2 was 5.9 kPa (45 mm Hg). Conclusions We believe this to be the first work to describe and quantify detectable end-tidal capnography in human cadavers. We have demonstrated that tracheal intubation of fresh frozen cadavers can be confirmed by life-like waveform capnography. This requires further validation in a larger sample size.

Do emergency physicians and radiologists reliably interpret pelvic radiographs obtained as part of a trauma series

Introduction Interpretation of pelvic radiography is an important component of the primary survey and is commonly performed by emergency physicians. Radiologists bring unique skills to trauma care, including choice of imaging modality and image interpretation. It is not clear if this limited resource is most efficiently used in the resuscitation room. No studies have compared radiologists and trauma clinicians in their ability to interpret pelvic radiographs following trauma. Objective To determine the sensitivity and specificity of trauma experienced and trauma inexperienced emergency physicians in detecting pelvic fractures compared with radiologists, the latter subgroup combined report being used as the gold standard. Setting and methods Prospective cohort study conducted in two large teaching hospitals in central London. All participants reviewed 144 consecutive pelvic radiographs performed each as part of a ‘trauma series’ and known to have undergone concomitant pelvic CT imaging. Results No statistically significant difference was found between radiologists and emergency physicians from a trauma centre in pelvic radiograph interpretation. Radiologist reporting was associated with an improved specificity compared with emergency physicians working in a non-trauma hospital (p=0.049). The study population missed 30% of fractures on plain radiography against the gold standard of CT. Discussion The ability to interpret trauma series pelvic radiographs is comparable between emergency physicians and radiologists. If this were also true of trauma chest radiographs, then the most valuable use of the radiologist may not be the resuscitation room but in rapid reporting of more complex imaging techniques. However, plain radiography is insensitive for pelvic fracture detection compared with CT, even in expert hands.

Logistics and Safety of Extracorporeal Membrane Oxygenation in Medical Retrieval

Abstract Objective. This article reviews the logistics and safety of extracorporeal membrane oxygenation (ECMO) medical retrieval in New South Wales, Australia. Methods. We describe the logistics involved in ECMO road and rotary-wing retrieval by a multidisciplinary team during the H1N1 influenza epidemic in winter 2009 (i.e., June 1 to August 31, 2009). Basic patient demographics and key retrieval time lines were analyzed. Results. There were 17 patients retrieved on ECMO, with their ages ranging from 22 to 55 years. The median weight was 110 kg. Four critical events were recorded during retrieval, with no adverse outcomes. The retrieval distance varied from 20.8 to 430 km. There were delays in times from retrieval booking to both retrieval tasking and retrieval team departure in 88% of retrievals. The most common reasons cited were “patient not ready,” 23.5% (4/17); “vehicle not available,” 23.5% (4/17); and “complex retrieval,” 41.2% (7/17). The median time (hours:minutes) from booking with the medical retrieval unit (MRU) to tasking was 4:35 (interquartile range [IQR] 3:27–6:15). The median time lag from tasking to departure was 1:00 (IQR 00:10–2:20). The median stabilization time was 1:30 (IQR 1:20–1:55). The median retrieval duration was 7:35 (IQR 5:50–10:15). Conclusion. The process of development of ECMO retrieval was enabled by the preexistence of a high-volume experienced medical retrieval service. Although ECMO retrieval is not a new concept, we describe an entire process for ECMO retrieval that we believe will benefit other retrieval service providers. The increased workload of ECMO retrieval during the swine flu pandemic has led to refinement in the system and process for the future.

Does end-tidal capnography confirm tracheal intubation in fresh-frozen cadavers?

Background Life-like end-tidal capnography (ETCO2) waveforms have been demonstrated in recently deceased and fresh-frozen cadavers following tracheal intubation, offering potential for high fidelity airway simulation training. As the mechanism for carbon dioxide production is not fully understood, it is possible that oesophageal intubation may also generate a capnograph. Our aim was to measure ETCO2 levels following (1) oesophageal and (2) tracheal intubation in fresh-frozen cadavers, and to observe the size, shape and duration of any capnographic waveform. Methods Four fresh frozen cadavers underwent oesophageal intubation by an emergency medicine specialist with confirmation by a second specialist. Hand ventilation with room air via a self-inflating resuscitation bag was provided at 12 breaths per minute for 2 min or until ETCO2 was zero for 10 consecutive breaths. ETCO2 and waveform morphology were examined and video recorded. The oesophagus was then extubated and the process was repeated for tracheal intubation. Results In no case was oesophageal ETCO2 detected. For two cadavers, life-like ETCO2 waveforms were achieved immediately after tracheal intubation, with maximum ETCO2 achieved by the second breath. In these cases waveform morphology was normal and persistent. Conclusions Cadaveric oesophageal intubation did not result in a capnography waveform, simulating live patients. When present, ETCO2 following tracheal intubation showed normal morphology which was sustained for 2 min. However, ETCO2 was not present following tracheal intubation in all cadavers. These results represent instrumentation on the cadavers for the first time after thawing and further work should assess the repeatability of the findings with subsequent intubations.

Review of aeromedical intra-aortic balloon pump retrieval in New South Wales.

Objectives The intra-aortic balloon pump (IABP) was first introduced in 1968 to augment cardiac output in the haemodynamically unstable patient and serve as a bridge to treatment options such as coronary artery bypass grafting and cardiac transplantation. Transfer of IABP-dependent patients for upgrade of clinical care is increasingly common and safe. In Australia, percutaneous coronary intervention centres can be located outside cardiothoracic surgical centres. This study reviews IABP medical retrieval by a doctor/paramedic team after implementation of a standardized protocol. Methods This was a retrospective case series review, using descriptive statistics. Results Greater Sydney Area Helicopter Emergency Service carried out 22 cases from 1 May 2007 to 31 December 2009. Median age was 62 years [interquartile range (IQR) 51–83], 67% were male. In all, 63% of patients were retrieved on inotropic support, 29% overall received invasive ventilation. Highest frequency indications were myocardial infarction, cardiogenic shock and bridge to coronary artery bypass grafts. There were complications during 18% of all retrievals and no adverse outcomes. Of the patients, 67% (14/21) were retrieved by road and 33% (7/21) by helicopter (longest distance 500 km). Median stabilization time by a retrieval team was 1 h 15 min (IQR 50 min to 3 h 30 min). Median mission time was 4 h 55 min (IQR 3 h 50 min to 8 h 54 min). Conclusion Our system offers a safe method of IABP medical retrieval. The doctor and paramedic combination complements strengths in logistics and critical care. This serves as a guide to other systems looking to put in place a similar model of care.

Helicopter emergency medical service registrars do not comprehensively document primary surveys.

Objectives In-hospital primary surveys undertaken on traumatically injured patients can be inaccurate and incomplete. This study examined the documentation of prehospital primary surveys conducted by Greater Sydney Area Helicopter Emergency Medical Service registrars on trauma patients. Methods A retrospective case sheet review of prehospital trauma primary surveys documented by Greater Sydney Area Helicopter Emergency Medical Service registrars was carried out using previously published methodologies. A 13-item prehospital primary survey score was created and analysed by registrar specialty. A linear mixed model was used to determine whether differences in prehospital primary survey score existed between specialties. A one-point difference in the mean scores was considered clinically significant. Results A total of 75 charts were reviewed. An unadjusted mean of 9.5±1.6 (SD) items, out of a possible 13, was documented. Documentation was found to be less complete for anaesthetic trainees (adjusted mean score=9.10) than for emergency medicine trainees (adjusted mean score=10.34). The difference in the mean scores was 1.24 (95% confidence interval, 0.25–2.23, t53d.f.=2.52, P=0.01). A significant clustering effect was identified for individual registrars (&khgr;21d.f.=6.03, P=0.01). A very good level of agreement was obtained between the PPSS raters (&kgr;=0.93, 95% confidence interval, 0.87–0.99). Conclusion Helicopter emergency medical service registrars do not comprehensively document prehospital primary surveys on traumatically injured patients. However, emergency medicine trainees document more completely than anaesthetic trainees. Individual registrar variation contributes significantly towards the completeness of prehospital primary survey documentation.

Potential complication of the cruciform trauma position

Dear Editor, Mitra and colleagues propose the cruciform position for trauma resuscitation in hospital to facilitate concurrent time-critical interventions in the multiply injured patient. We have been advocating this position for the pre-hospital management of patients in traumatic cardiac arrest for the same reasons of expedient ‘horizontal resuscitation’ and bilateral surgical access to the thorax. The cruciform position is easily achievable for patients who are supine on the ground, but those on stretchers require their arms to be held out by on-scene assistants. Once patients are loaded into an ambulance or most types of emergency medical service helicopter, cruciform positioning becomes impossible, hence our discouragement of loading and transport prior to completion of critical procedures. We share our experience of one critical complication of the cruciform position. Intraosseous access is increasingly utilised by pre-hospital providers as the initial and sometimes sole source of resuscitative vascular access. The proximal humerus is the preferred site for intraosseous cannulation by some services as it provides