Recent eLetters

I was interested to read the study by Grosomanidis et al., which compared intubation of a manikin using the intubating laryngeal mask airway (iLMA) and Airtraq optical laryngoscope in various non-conventional patient positions [1]. The authors report that those anaesthetists who participated in the study required a significantly greater number of attempts (and time) to achieve intubation via the iLMA when the operator was facing the manikin lying in the lateral decubitus position, compared with the three other positions under investigation.

Aware that Komatsu et al. had demonstrated comparable success rates for intubations via the iLMA in supine and lateral positions [2], the authors suggest that the problems they encountered could have been due to a greater difficulty in manipulating the airway of the manikin, compared to that of the human. However, in Figure 3 (Image D), the operator can be seen attempting intubation of the manikin in the lateral position without any manipulation of the handle of the iLMA.

Early experience with the iLMA suggested that a learning curve of approximately twenty cases existed for proficiency in tracheal intubation via the device [3]. However, subsequent refinements to the recommended insertion technique managed to produce significant improvements in first- time intubation success rates [4]. The technique currently recommended is called the 'Chandy manoeuvre', which can be expected to improve first-time intubation rates via the iLMA to levels approaching 100%. If the anaesthetists who participated in the study did not all utilise the formal Chandy manoeuvre during attempts to intubate the manikin in the lateral position, then this could explain the findings.

The authors go on to state that few cases have appeared in the literature where the iLMA has been used in the sitting position for prehospital trauma care. They reference my paper from 2000, but I would draw their attention to a paper I published in 2009 detailing prehospital use of the iLMA in five patients with severe polytrauma [5]. In this study, three of the patients were trapped in a sitting position and all three were successfully treated using the iLMA and went on to survive to discharge from hospital. For those who are interested, a full description of the Chandy manoeuvre appears in this paper.

In addressing the suitability of the iLMA and Airtraq for prehospital airway management, the authors fail to point out one crucial difference between the two devices, viz., that the Airtraq has no inherent ability to oxygenate patients, except by facilitating tracheal intubation. In contrast, the iLMA functions as a rescue ventilation device in its own right, permitting rapid re-oxygenation of the hypoxaemic patient prior to any intubation attempt. Furthermore, in order to facilitate intubation, the Airtraq user relies upon a satisfactory view of the larynx. But what often defeats rescuers in prehospital trauma situations is the presence of blood and secretions in the airway obscuring the laryngeal inlet. In the case of the iLMA, no view of the larynx is required since the device is specifically intended to facilitate blind intubation of the trachea.

Andrew M Mason

(Accredited Basics Immediate Care Physician, Suffolk Accident Rescue Service, Ipswich, UK, & Honorary Physician, East of England Ambulance Service NHS Trust)

REFERENCES:

[1] Grosomanidis V, Amaniti E, Pourzitaki Ch, Fyntanidou V, Mouratidis K, Vasilakos D. Comparison between intubation through ILMA and Airtraq in different non-conventional patient positions: a manikin study. Emergencey Medicine Journal 2012; 29: 32-36. doi:10.1136/emj.2010.100933.

[2] Komatsu R, Nagata O, Sessler DI, et al. The intubating laryngeal mask airway facilitates tracheal intubation in the lateral position. Anesthesia & Analgesia 2004; 98: 858-61.

[3] Baskett PJF, Parr MJ, Nolan JP. The intubating laryngeal mask. Results of a multicentre trial with experience of 500 cases. Anaesthesia 1998; 53(12): 1174-9.

[4] Ferson DZ, Rosenblatt WH, Johansen MJ, Osborn I, Ovassapian A. Use of the intubating LMA-Fastrach in 254 patients with difficult-to- manage airways. Anesthesiology 2001; 95(5): 1175-1181.

[5] Mason AM. Prehospital use of the intubating laryngeal mask airway in patients with severe polytrauma: a case series. Case Reports in Medicine 2009; doi:10.1155/2009/938531. Available for free download at: http://www.hindawi.com/journals/crim/2009/938531/

Conflict of Interest:

None declared

Conflict of Interest:

None declared

Letter to the Editor Henry G Watson* & James Ferguson *Department of Haematology Aberdeen Royal Infirmary, Foresterhill, Aberdeen, Scotland AB25 2ZN Email: henrywatson@nhs.net Tel 00-44-1224-553394

Department of Emergency Medicine Aberdeen Royal Infirmary, Foresterhill, Aberdeen, Scotland Email: j.ferguson@nhs.net Tel 00-44-1224-550506 Keywords: Intracranial haemorrhage, warfarin, prothrombin complex concentrate Word Count 675

We welcome the review of this common clinical problem and broadly agree with the conclusions arrived at by Leiblich and Mason1. One aspect of management that requires further investigation is the appropriate strategy for reversal of anticoagulation. Clinical studies consistently demonstrate that there is a higher incidence of intracranial haemorrhage (ICH) in patients who are anticoagulated with warfarin compared with controls who are not. Whilst there may be an increased risk of ICH, which is attributable to the indication for anticoagulation, there is a strong rationale to indicate that anticoagulation per se contributes to the increased bleeding risk in this group. As such, in the context of ICH in an anticoagulated patient there is a rationale, although little evidence, for reversal of anticoagulation. Our contention is that if anticoagulation is to be reversed then there is a strong rationale for achieving this as quickly and completely as possible. Although in the Swedish study, cited by Leiblich and Mason, the outcomes were apparently poorer for recipients of PCC compared with FFP it is highly likely that this observation resulted from clinical bias towards the use of PCC in patients with more severe head injury or in those perceived by the investigators to be at a higher risk of ICH than those given FFP or nothing2. In reality, prothrombin complex concentrates are likely to provide significant benefits over fresh frozen plasma for the rapid reversal of the anticoagulant effect of warfarin. PCCs are manufactured from pooled non-UK donor plasma, and subjected to two virus inactivation or removal steps while FFP is a single donor product which, at present in the UK, is still made from UK donor plasma with the attendant risks of vCJD transmission. FFP is blood group specific and the delay associated with determining blood group and thawing plasma for clinical use is not shared by PCC, which may be stored in a pharmacy, clinical areas or blood banks and is available for immediate release upon request. PCC requires about 10 minutes for re-constitution from its lyophilised state. The reversal of warfarin anticoagulation using coagulation factors is all about replacing the factors II, VII, IX and X, which are depleted by the action of warfarin. PCC contains all of these factors in a high concentration but no other procoagulant factors while FFP contains all the circulating prothrombotic factors in a dose of approximately 1u/ml. Although, this is subject to significant variation between units. To reverse an INR of >5 in a 70 Kg patient, based on manufacturers recommendations, would entail giving a dose of around 3000 units of PCC which would be delivered in a volume of 120-140 ml over between 18 and 40 minutes. The equivalent dose of FFP to deliver this dose of coagulation factors is around 3000 ml, which would predictably take hours to infuse and which would be more likely to be associated with circulatory overload. The only possible caveat of the use of PCC is that there have been reports of subsequent thrombotic events in recipients3. The role of PCC in these events is unclear as they are occurring in a group with a pre-existing risk of thrombotic events sufficient to warrant warfarin therapy. In addition, these patients may have had an additional acute prothrombotic event which resulted in the need for reversal. However, even bearing this small risk in mind, the prognosis for anticoagulant related ICH is so poor that this small risk is unlikely to detract from the overall potential benefit of reversal. Finally, a recent economic appraisal comparing the use of FFP and PCC within the UK healthcare system indicates that there is a cost benefit for the use of PCC as opposed to FFP in anticoagulated patients presenting with ICH4. In summary, although there are few good data to support rapid reversal of anticoagulation in patients on warfarin who sustain ICH, there is a strong rationale for this. We would suggest, in fitting with UK national guidelines5, that where reversal is considered appropriate this should be achieved using PCC as opposed to FFP for the reasons outlined above Conflict of interest declaration HGW received a lecture fee from CSL Behring in 2007 JF has no conflict of interest to declare References 1. Leiblich A & Mason S Emergency management of minor head injury in anticoagulated patients. Emerg Med J. 2011;28:115-118 2. Sjoblom L, Hardemark HG, Lindgren A et al Management and prognostic features of intracerebral hemorrhage during anticoagulant therapy: a Swedish multicenter study. Stroke 2001;32:2567-2574 3. K?hler M, Hellstern P, Lechler E et al. Thromboembolic complications associated with the use of prothrombin complex and factor IX concentrates. Thromb Haemost. 1998;80(3):399-402. 4. Guest JF, Watson HG, Limaye S. Modelling the cost-effectiveness of prothrombin complex concentrate compared to fresh frozen plasma in emergency warfarin reversal in the UK. Clinical Therapeutics 2011 (in press) 5 .Baglin TP, Keeling DM, Watson HG; British Committee for Standards in Haematology. Guidelines on oral anticoagulation (warfarin): third edition -2005 update. Br J Haematol. 2006;132(3):277-85.

Conflict of Interest:

None declared

I have recently read the case report "A complication of the use of an intra-osseous needle" by Helm, Goller, Hackenbroch and Hossfeld published online in your Emergency Medicine Journal June 2, 2011. This is a well written and informative article that discusses the uses and potential complications of intra-osseous infusion.

I am concerned about the actual FAST1 device that was used in this case report. This was an older version that still provided a removal tool to remove the metal portal ("end of the needle"). Pyng, the manufacturer of the FAST1 redesigned the FAST1 over 4 years ago because of a limited number of reports of the portal being left in the sternum during the removal procedure. The redesigned FAST1 strengthened the portal-plastic tubing connection and did away with the need for a removal tool. The last of the FAST1's with the removal tool was shipped over 3 years ago. Specifically, these devices were last shipped in AUG 2008. The newly designed devices without the removal tool began to be shipped in NOV 2007. Additionally, the product has a stated shelf life or expiration date 2 years after manufacturing.

Therefore the device that was reported in this case study was over 3 years old. Some of the reasons that the FAST1 has a 2 year shelf life are sterility and a possible degradation of components exposed to the potentially harsh climates (extremes of heat, cold and humidity) that the military routinely trains and operates in.

As a retired military physician I am well aware of the military logistics systems, cost constraints and the need sometimes to "use what you have". This brings up the more significant issue of patient safety and in this case, training safety. Almost all medical materiel, from the FAST1 to medications, IV fluids and various electronic monitoring, treatment and diagnostic devices have a designated shelf life or expiration date. These dates are determined by detailed studies and regulatory practices. Use of any medical materiel beyond its expiration date for any reason poses a serious risk to the patient or in this case training volunteers. Regardless of where one practices medicine from a "brick and mortar" medical center or hospital to austere frontline care it is imperative to check and examine the expiration dates of all medical materiel on a routine basis, from receipt through storage and prior to use with a patient to ensure quality care and patient safety.

DR. Alan Moloff, MPH COL (RET) U.S. Army CMO, Pyng Medical Corp.

Conflict of Interest:

None declared

Dear Collegues,

We were very glad to reply your letter posted online on the emj website in october, 6 2011. We read very carefully your concerns regarding the verifiability of cyanide as the poisoning agent. Certainly You can agree with us that, in a brief report with a fixed length, it is very difficult to give all the information and in some case you have to choose what you consider more important . In this case we thank you for giving us the opportunity to clarify some points that obviously were not so clear in the original paper.

First of all, the patient was uncooperative but not unresponsive; so we asked her if she had effectively chewed and swallowed the apricot seeds and she confirmed it, enjoying the bittersweet taste. We also visualized many fragments of seeds on gastric lavage, so we were sure that she had masticated and swallowed the seeds.

For your second objection, unfortunately we are not able to measure cyanide levels in our emergency department, so we consider the possibility that the metabolic acidosis with increased anion gap was due to an abnormal lactate production, as we can see in cyanide poisoning [1].

Moreover the anamnesis of the patient was negative for inappropriate ingestion of drugs of any kind, and she confirmed to us that she did not ingest any other substance. She did not take medications at home and she has no access to medications of her parents. Finally, we reported that the patient was dyspnoic, hypotensive and she developed metabolic acidosis with increased anion gap [2].

These symptoms, according with the anamnesis of recent ingestion of cyanide-releasing substance, suggested us the diagnosis of cyanide poisoning [3]. In addition the quick response of the patient to the antidotal therapy for cyanide poisoning indirectly confirm the cyanide intoxication.

Thank you again and best regards

Cigolini Davide, MD Ricci Giorgio, MD

References

[1] Beasley DM, Glass WI. Cyanide poisoning : phatophysiology and treatment reccomendations. Occup Med (Lond) 1998;48:427-31

[2] Cigolini D, Ricci G, Zannoni M et al. Hydroxocobalamin treatment of acute cyanide poisoning from apricot kernels. Emerg Med J. Sep 2011;28(9):804-05

[3] Vogel SN, Sultan TR, Ten Eyck RP. Cyanide poisoning. Clin Toxicol 1981;18:367-83

Conflict of Interest:

None declared