Anaesthesia Product News

5th Hands On Cadaver Workshop On RF Lesioning Techniques For Intervetebral Disc Biacuplasty & Sacroiliac Neurotomy
Authors: Dr Ron Cooper – Causeway Hospital, Coleriane, NI and Dr Neal Evans – Wycombe General Hospital – Bucks

Emerging Uses Of Capnometry In Emergency Medicine
Published by Communicore under an educational grant from PHASEIN AB, Sweden.

5th Hands On Cadaver Workshop On RF Lesioning Techniques For Intervetebral Disc Biacuplasty & Sacroiliac Neurotomy
Authors: Dr Ron Cooper – Causeway Hospital, Coleriane, NI and Dr Neal Evans – Wycombe General Hospital – Bucks

Summary

After the past success of ‘hands-on’ cadaver workshops the 5th workshop was held at the Nottingham City Hospital on 19th September 2009. Fourteen Pain Management Specialists from across Europe attended the workshop, which was conducted by Dr A R Cooper (Coleraine NI) and Dr Neal Evans (High Wycombe). The workshop is targeted for specialists who are interested in using the Cooled RF technology from Baylis Medical to treat Discogenic Pain and SIJ syndrome.

Cooled-RF treatment for Discogenic Pain & SIJ Syndrome
The Baylis Pain Management System for the treatment of Discogenic pain (TransDiscal™) and for treatment of the Sacro-Iliac Joint Syndrome (SInergy™), uses Cooled RF technology. The Baylis Cooled RF system allows users to create lesions in nerve tissue to disrupt pain originating from discs, or the SI joint, and surrounding connective tissue. The consistence of lesion shape and size is precisely maintained by the Baylis Pain Management Generator.

The TransDiscal™ system uses Cooled Bipolar RF, while the SInergy™ system uses Cooled Monopolar RF. In particular, the treat-ment of the SIJ has often not resulted in lasting pain relief, so the SInergy™ system is of particular interest.

The procedures are minimally invasive and take about 40 minutes to complete. Specialists attending the course are trained to identify the landmarks in the particular anatomy to allow easy placement of the introducers correctly to achieve effective results and also ensure safety.

Patients typically experience some level of relief from the treatment within 7-10 days after the procedure.

The key benefits of the Cooled RF System are as follows:

Internally Cooled RF for greater power applications
Consistent lesion shape and size
Multi-directional approach to target nerves for SIJ
Minimal disturbance to overlaying soft tissue

The Workshop Presentations
Ms Annaise Magloire from Baylis spoke about the physics of Cooled- RF. This included the mechanisms of the RF systems, the advantages of Cooled-RF and practical tips of equipment handling.

Dr Ron Cooper discussed discogenic pain, its prevalence, innervation of the disc area and pathology. He touched on existing treatments, the history of heat therapies, and finally Disc Biacuplasty procedure. He went on to detail patient selection, the procedure, inclusion/exclusion criteria, potential complications (rare) and follow up.

Dr Neal Evans presented SIJ anatomy and SIJ innervation studies, before discussing the technique, electrode/probe placement, prevalence of the problems, lesion properties and patterns, plus procedure time savings.

Both Pain Specialists discussed practical ‘tips and traps’ of the two therapies – and these proved particularly helpful during the practical sessions.

The Workshop Practicum’s
Delegates were divided into two groups for the practical workshop. Group A had hands on training on the Disc Biacuplasty procedure from Dr Cooper, whilst Group B had training on treating SIJ pain, under the watchful eyes of Dr Evans.

Equipment for the two systems is similar and comprises Introducers, probes, burettes, Pain Management Generator and pump unit. The latter controls flow rate of sterile water to the probes, and is connected to the generator which provides the RF energy. Delegates were able to look at the parameters measured and functionality of the system, via an LCD screen on the generator. They were also able to handle the introducers and slide into place the appropriate probe.

In the theatre, attendees were especially concerned with locating the needles, under C-arm vision on monitors. These were placed into the appropriate space, depending on whether they were undertaking a Biacuplasty procedure with the TransDiscal™ system (Dr Cooper), or the SIJ procedure with the SInergy™ system (Dr Evans). The hands-on sessions were especially appreciated and delegates benefited from each others experiences in establishing correct locations for the probes, in order to (ultimately) direct the RF energy. ‘Tips of the trade’ such as placing a little broad spectrum antibiotic solution into the needle track, once the procedure had been completed, were enthusiastically received by the delegates from the consultant experts.

All attendees were then able to ask further questions in a wrap-up session. It was emphasised that the most benefit of the workshops would in doing actual cases by the attendees

Course Conclusions
Asked to rate six key aspects of the workshop on a 1-5 basis, with 5 being excellent, all boxes were in the 4-5 range exclusively.

The main requirements from delegates were for:

A broader spectrum of RF procedures to be included
Gaining accreditation from the Royal College of Anaesthetists, so that CME points could be awarded in future

Both BVM Medical and Baylis Medical expressed their thanks to Dr Cooper, Dr Evans and the two technicians from Ireland who attended to operate the C-Arms, provided by GE Healthcare.

Further similar events are planned and, for information on these, or for more information on the Baylis RF systems, please telephone BVM on 01455 614555.

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Emerging Uses Of Capnometry In Emergency Medicine
Published by Communicore under an educational grant from PHASEIN AB, Sweden.

The Physiologic Basis for Capnometry
Capnometry is based on a discovery by chemist Joseph Black, who in 1875 noted the properties of a gas released during exhalation that he called “fixed air.” That gas—carbon dioxide—is produced as a consequence of cellular metabolism, a waste product of the process of oxygen and glucose combining to produce energy. Carbon dioxide exits the body via the lungs. The amount of CO2 in exhaled breath reflects cardiac output and pulmonary blood flow as the gas is transported by the venous system to the right side of the heart and then pumped into the lungs by the right ventricle. Carbon dioxide is involved not only in oxidative cellular metabolism, but also in gas transport and ventilation. Capnometers measure the concentration of CO2 exhaled at the end of the breath, commonly known as the end-tidal breath CO2 (ETCO2). When outside the normal range, high or low, it indicates a problem with ventilation that requires immediate action. As long as the heart is beating and blood is flowing, CO2 is delivered continuously to the lungs for exhalation. Anything that interferes with normal ventilation quickly changes ETCO2, even as SPO2 —the indirect measurement of oxygen saturation in the blood—levels remain high. Thus, CO2 is a better, more sensitive and more rapid indicator of ventilation problems than SPO2 measurements.¹

Why ETCO2 Monitoring is Important
Capnometry can be a life saving modality, because changes in ETCO2 levels are an early indicator of several potentially dangerous conditions. A sudden decrease can indicate, for example, hyperventilation or impending shock; a sudden increase can indicate malignant hyperthermia even in the absence of changes in breathing. The absence of ETCO2 in an intubated patient is an indicator of a misplaced endotracheal tube, a life-threatening situation. Too much or too little exhaled CO2 not only foreshadows deleterious physiological trends in critically ill or injured patients but abnormal blood CO2 in itself it can have serious consequences. It is generally accepted that CO2 monitoring is the practice standard for determining whether endotracheal tubes are correctly placed. However, there are other important indications for its use as well. Ventilatory monitoring by ETCO2 measurement has long been a standard in the surgery and intensive care patient populations. Carbon dioxide monitoring should be regarded in the pre-hospital setting like it is in the surgical suite: as a vital sign of a patient’s ventilatory status, helping to guide immediate and future treatment. Emergency Medical Services (EMS) organizations understand the importance of monitoring ventilation in addition to oxygenation in the critically ill or injured patient and have begun incorporating protocols that include this vital parameter. Yet, the applications of CO2 monitoring in this setting have been limited despite data demonstrating its value.² That CO2 monitoring is not as widely utilized as it could be in pre-hospital medicine is an issue that deserves new consideration.³

Where is CO2 Monitoring Underutilized?
Thousands of patients are intubated or given bag-valve-mask (BVM) ventilation every year in the pre-hospital setting. In contrast to the controlled environment of the operating room or the ICU, the circumstances in which EMS personnel treat patients are unique. Patients are often in a high-motion, physically challenging environment in which monitoring equipment can malfunction and in whichlarge, bulky devices are impractical. Yet, proper support and monitoring of ventilation are critical for successful outcome in these seriously ill patients. Oxygen saturation, or SPO2, can be measured as an indicator of ventilation, but haemoglobin oxygen saturation is not as rapidly sensitive to changes in ventilatory status as ETCO2. Further, studies in ambulance settings have demonstrated that hypothermia and vasoconstriction might impair the ability of oximeter sensors to detect changes in SPO2 even in the presence of respiratory distress. Capnometry in the emergency setting can provide the data needed to monitor and correctly adjust ventilation parameters much more quickly and sensitively.

The most common reason in the pre-hospital emergency setting to use capnometry is to ensure that endotracheal tubes are correctly placed, an important problem in an out-of-hospital setting. One study showed that unrecognized oesophageal intubation is as high as 25%.⁴ Another study showed unrecognized endotracheal tube misplacement is present in 3% of cardiac arrest patients and in 17% of trauma patients transported to a Level 1 trauma centre. It can be argued that even patients who are not intubated but are receiving BVM, should also have their CO2 levels monitored. Although they are not subject to the potential disaster of a misplaced endotracheal tube, they are vulnerable to the consequences of over- or under ventilation. In addition, tracking the ETCO2 concentration of an artificiallyventilated patient has predictive value in determining the efficacy of CPR.^5,6,7,8 The use of capnometry could prevent serious problems in pre-hospital patient management as well assist in triage after the patient arrives in the hospital emergency department, but it is not universally employed. One EMS director in a large U.S. city estimates that only 75% of EMS systems have some form of ETCO2 monitoring, meaning that 25% do not.⁹ A 2005 study in Germany showed that capnometers were available to only 66% of emergency medical personnel,¹⁰ and while this percentage has likely grown in the last several years, ETCO2 monitoring is far from universal in EMS systems.

Current Methods of Measuring ETCO2
There are three technologies currently available for CO2 monitoring: colorimetric devices, cable-connected mainstream, sidestream, and self-contained mainstream. This last category is the newest entry in the armamentarium of available devices. Mainstream or sidestream devices can either display CO2 as a digital readout (capnometer) or as a waveform (capnograph).

Colorimetric devices detect and present a range of ETCO2 in a qualitative format rather than as a specific number. They display colour changes indicative of the presence of CO2. This type of device has a pH-sensitive chemical indicator visible through a clear dome that turns from purple to yellow when attached to a correctly intubated patient, indicating that CO2 is in the expired breath and the tube is therefore in the trachea. If it is attached to a patient with the tube in the oesophagus, it remains purple. While it is easy to use, it can give false positive readings caused by the presence of CO2 in the oesophagus, from carbonated beverages ingested by patients just prior to application, or if certain gastric contents or drugs are present.¹¹ In addition, its sensitivity is markedly reduced in patients with cardiac arrest and low perfusion,¹² up to an incidence of 13% failure rate.¹³ Finally, colorimetric indicators require six breaths before they can give an accurate reading. Colorimetric devices are placed on ambulances in the intubation airway bag and are used by ALStrained personnel whenever an intubation is required. They are also widely available in hospital crash carts because of their ease of use and convenience. However, due to their unreliability, some countries in Europe have prohibited their use in both pre-hospital and hospital settings.¹⁴

Cable-connected mainstream or sidestream monitors measure CO2 using a sensor having a source of infrared light, a chamber containing the gas sample, and a photo detector. When the expired CO2 passes between the beam of infrared light and the photo detector, the light absorption is proportional to the concentration of CO2 in the gas sample. The photo detector response is calibrated with known concentrations of CO2 and stored in the monitor’s memory. In sidestream designs, a portion of the patient’s expired gases is transported from the airway through a sampling tube to the sensor. Measuring the concentration of a gas distant from the sampling site is however problematic, since the condition under which the sample is taken is subject to varying water content, humidity, pressure and temperature. Mainstream designs have by contrast the source of infrared light and the photo detector located right at the airway. This arrangement results in an immediate measurement without delays and a precise CO2 waveform.

Cable-based sidestream/mainstream CO2 measurement is an optional feature in defibrillators or “all in one” patient monitors utilized by ALS-trained paramedics, accomplished by the addition of a sensor added to others such as ECG, SPO2, and non-invasive blood pressure. The CO2 information is registered and displayed on the screen of the device.

The most recent innovation in ETCO2 monitoring technology is a hand-held, battery-powered self-contained mainstream device called EMMA (PHASEIN AB, Sweden). The EMMA monitor detects ETCO2 values in every breath while also showing the respiratory rate. EMMA is very lightweight, weighing only about 60 grams and requires no calibration. It operates on two standard AAA batteries, and takes less than a second to register accurate measurements, which are shown on an LED display.

Both cable-connected mainstream or sidestream devices and self-contained mainstream devices provide quantitative displays of ETCO2. The results can be displayed as continuously varying digital readouts or a continuous waveform.

Different from colorimetric devices, quantitative capnometers display true readings of carbon dioxide usually expressed as a partial pressure of CO2 in units of mmHg having a normal value between 35-45 mmHg. The use of quantitative capnometers is an advantage in pre-hospital medicine because it allows fast and reliable insight into ventilation, circulation, and metabolism. The availability of this technology may allow the wider use of capnometry in EMS because of its ease of use and cost effectiveness. It could also lead to an expansion of applications within the emergency medicine spectrum that are not common now but should be considered as the value of CO2 monitoring is recognized well beyond its standard application as an endotracheal tube placement verifier. Capnography refers to the continuous, trend and real-time CO2 waveform display. These tracings have recognizable patterns that are helpful to advanced analysis of respiration, ventilation, and perfusion. Capnography is regarded as the ultimate form of CO2 monitoring, includes a number of important parameters, and can be helpful in the differential diagnoses of a number of serious conditions. The wide availability of CO2 monitoring devices suggests that there is no technological impediment to its wider use. Some of the newer uses of capnometry are evolving as its importance in the critically ill and injured patient are being recognized.

Emerging Uses of Capnometry in Pre-hospital Medicine ETCO2 monitoring during bag-valve-mask ventilation
Bag-valve-mask ventilation (BVM) is one of the most common methods of ventilating patients during cardiac arrest, respiratory arrest, and trauma, and a frequently used procedure for those trained in Basic Life Support (BLS) since they are not certified to use devices that invade the airway. While other technologies may appear to have superceded it, there are clinicians who assert that BVM is at least as effective in ventilating patients as endotracheal intubation as demonstrated by survival rates. In fact, a large study concluded that the latter leads to longer pre-hospital times.¹⁵ However, BVM is thought to be a difficult procedure to perform, sometimes requiring two operators who must remain focused on maintaining a seal on the patient’s mouth while delivering ventilation. Studies have shown that varying BVM skill levels among EMS providers have led to poor patient outcomes.^16,17 The use of capnometry could improve these outcomes by providing real time continuous feedback about adequacy of ventilation. However, the segmentation of levels of prehospital emergency care that EMS personnel are certified to provide has limited its use by more basic-level providers. In the United States, the levels consist of (1) Medical First Responder, (2) Emergency Medical Technician-Basic (EMT-B), (3) Emergency Medical Technician Intermediate (EMT-I), and Emergency Medical Technician-Paramedic (EMT-P). The last two categories, comprising over 200,000 EMTs as of 2006,¹⁸ of whom 25% are paramedics, are trained in Advanced Life Support (ALS), which includes the use of capnometry. Levels 1 and 2—First Responders and EMT-Basic operate advanced medical devices such as bag mask resuscitators, facial masks, oxygen equipment and monitors, ventilators, and most recently, the automated external defibrillator (AED). They would be able to use portable mainstream monitors with little training but are not currently certified to do so.

ETCO2 monitoring during transport both to and within the hospital
Several published studies have documented the importance of CO2 monitoring of critically ill or injured patients during transport,^19,20,21 whether from the ambulance or helicopter to the emergency department, or from the emergency department to other areas of the hospital. These patients are generally intubated and some are on mechanical ventilators. Both pediatric and adult advanced life support guidelines require ETCO2 monitoring during transport.²² A sudden change in CO2 levels could indicate serious conditions such as endotracheal tube displacement, malfunction of the mechanical ventilator, or loss of pulmonary blood flow. However, even nonintubated patients could benefit from CO2 monitoring, perhaps being an even more vulnerable population since they do not have an endotracheal tube in place and are subject to rapid changes in respiratory status. In two studies, capnometry provided more reliable data than oximetry on patients during transport,^23,1 leading the authors to recommend the use of CO2 monitoring for victims of even minor trauma during transport to the emergency department. Often portability is a factor in the choice of capnometers, especially when patients are connected to other space-occupying monitors. In some cases, time to transport patients for in-hospital treatment is a factor and thus a reliable, portable device that does not need calibration is an advantage.

ETCO2 monitoring to guide ventilation parameters
Much has been published about the importance of monitoring ventilation to avoid hyperventilation in particular. It is well recognized that hyperventilation is harmful to patient outcomes, yet it continues to be seen in the pre-hospital setting. Excessive ventilation rates result in significantly increased intrathoracic pressure and decreased coronary perfusion pressures and survival rates.^{24, 25} The goals for patients receiving artificial ventilation are controlled ventilation, optimized inspiratory time, and airflow.²⁶ The problem of hyperventilation is particularly relevant in patients with severe head-injuries in whom its negative effects have been intensively studied. In fact, the use of pre-hospital intubation has been challenged on the grounds that it predisposes to hyperventilation.²⁷ Careful monitoring of CO2 and respiratory rate is required for the prevention of hyperventilation and is paramount to achieving improved outcomes in the field.²⁸ Hyperventilation is an issue as well with the use of paramedic rapid sequence intubation (RSI) in patients with severe head-injuries. There are mixed reports on whether or not RSI protocols increase intubation success in patients who cannot be easily intubated without the use of medications.^29,30 Two San Diego studies were conducted to look specifically at the traumatic brain injury population in whom the risks of hyperventilation are well known. The first was a multi-agency ground transport study designed to explore the impact of hypoxia and hyperventilation on outcome. One of the study participants used portable digital CO2 monitors with ventilation parameters modified to target ETCO2 values of 30 to 35 mmHg. Patients in the ETCO2 monitored group had a lower incidence of inadvertent severe hyperventilation than those without ETCO2 monitoring; those who were monitored also had a reduced mortality rate. The authors concluded that the use of ETCO2 monitoring is associated with decreased inadvertent severe hyperventilation and those patients who were not hyperventilated had a lower incidence of mortality.³¹

The second study was conducted in an air medical transport setting. It showed a different outcome: patient clinical parameters improved with paramedic RSI. There was a statistically significant decrease in patient mortality with air transport compared with the ground transport. Air medical crews used capnometry to guide ventilation on all study patients. The authors concluded that better outcomes may be attributed to the use of capnometry to guide ventilation.³²

Spot checking ETCO2 throughout the spectrum of emergency care
Another application of capnometry is to spot check ETCO2 levels and respiratory rates in patients as they progress through the emergency management system. Spot checking cannot practically be performed by equipment requiring time consuming set up or calibration. With a portable capnometer connected to a properly sealed face mask, any EMT or First Responder could ascertain ETCO2 and respiratory rate in only two breaths. The results of spot checking could suggest a change in medical management or verify that current procedures are working.

ETCO2 monitoring during emergency department delays
Because of the overcrowding of emergency departments especially during multiple trauma incidents, patients in the emergency department may experience delays until the appropriate specialists can be found to decide upon diagnosis and/or treatment. In such cases, fundamental to the appropriate care of these patients is the use of monitoring devices to ensure that patients remain stable until definitive treatment. In addition to monitoring of oxygenation, cardiac output, arterial perfusion pressure, intravascular volume, and markers of tissue hypoxia, ventilation should be monitored via capnometry as well.³³

ETCO2 monitoring for assessment of the efficacy of CPR and for prediction of survivability
A number of animal and human studies have shown an excellent correlation between ETCO2 and cardiac output during cardiopulmonary resuscitation and during states of low blood flow,34 making capnometry an effective tool to assist in evaluating the efficacy of cardiopulmonary resuscitation efforts. Reductions in ETCO2 are associated with comparable reductions in cardiac output; increases in ETCO2 are associated with return of spontaneous circulation (ROSC). The interpretation of ETCO2 in the field has to take into account that controlled ventilations may be difficult or impossible when manual CPR is interrupted by patient movement or a change in rescuer position. However, several studies have concluded that certain changes in ETCO2 levels are associated with successful CPR. A key study found that a rapid increase in CO2 levels within 30 seconds of ROSC, followed by a decrease four minutes later that remained stable, is an almost immediate indicator of successful resuscitation.⁵

Carbon dioxide monitoring has also been used to predict out-of-hospital cardiac arrest survival. A 1985 study looked at this question in 34 patients, of who nine survived resuscitation. These nine patients had higher average ETCO2 levels during CPR than the 25 who did not.⁵ Other studies confirmed these findings via different methodologies.34 One of them was performed in 150 consecutive victims of cardiac arrest outside the hospital who had electrical activity but no pulse. The patients were intubated and evaluated by mainstream ETCO2 monitoring. The authors’ hypothesis was that an ETCO2 level of 10 mm Hg or less after 20 minutes of CPR would predict death. Of the 150 patients, 35 patients survived to hospital admission, and in fact, the study showed that after 20-minutes of CPR, an ETCO2 value of 10 mmHg or less was predictive of death.⁸ Other studies confirm the 10 mmHg threshold. One found that initial, final, maximum, minimum, and mean ETCO2 values were all higher in patients who were resuscitated than in those who were not. No patient with a reading below 10 mmHg survived.⁷ The data from multiple studies confirm that capnometry appears to offer an effective tool to evaluate the progress and results of cardiopulmonary resuscitation and should be more widely used for this purpose by both ALS and BLS providers.

The Future of Capnometry in Emergency Medicine
Based on the abundance of published studies, the value of ETCO2 monitoring in emergency medicine is increasingly clear. Used in the past primarily for verification of correct endotracheal tube placement, its utility in monitoring ventilation in both intubated and critically ill non-intubated patients is being recognized. It is particularly effective in patients in whom inadvertent hyperventilation can cause a secondary injury and in assessing the efficacy of cardiopulmonary resuscitation. Its value in monitoring critically ill and injured patients during transport not only by ambulances or helicopters to hospitals but also within the hospital has resulted in practice standards adopted by a number of professional organizations worldwide. The role of ETCO2 monitoring is also evolving within the hospital. There is increasing evidence that it is underutilized in this setting, perhaps because its critical importance in verifying correct endotracheal tube placement has limited the recognition of its utility in other clinical circumstances. It is recognized that pulse oximetry values can remain high for a considerable time while respiratory distress remains undetected: only ETCO2 monitoring will rapidly indicate impending respiratory system deterioration. Checking ETCO2 levels when respiratory and ventilatory distress is suspected should be part of emergency department protocols. Spot checking ETCO2 in both intubated and non-intubated patients represents another important use of capnometry, made more practical by the availability of the new portable, mainstream capnometers.

Finally, making capnometry a standard for BLS providers is the next positive step in patient care. The difficulty of BVM ventilation and studies confirming poor outcomes for BLS personnel attributed to their varying skills argue for using capnometry whenever bagvalve-mask ventilation is performed. Cost is universally a consideration when the adoption of new technology is considered. Recently, advances in sensor design and miniaturization have made ETCO2 monitoring more economical. Patients are often in physically inaccessible locations, time is always of the essence, and low light often make attaching monitors to patients and reading the display a challenge. Having a rugged, portable, mainstream capnometer that can give both CO2 measurements and respiration rate accessible in an EMS “grab bag” is a clinical advantage.

Pre-hospital medicine is at an exciting time in its development as a specialty. Not only does it attract people whose dedication to quality patient care is superior, it is innovative in adopting new technologies from clinical areas outside EMS for its unique patient population. Capnometry, long established as essential in the surgical suite and in intensive care, is just coming into its own in prehospital medicine. It is clear from the data³⁶ that it should be more widely applied. The availability of portable, quantitative capnometers makes it cost effective and convenient to carry out in a time sensitive, geographically challenging field of medicine.

References

Kober A, Schubert B, et al. Capnography in non-tracheally intubated emergency patients as an additional tool in pulse oximetry for prehospital monitoring of respiration. Anesth Analg 2004; 98: 206-210.
Kupnik D, Skok P. Capnometry in the prehospital setting: are we using its potential? Emergency Medicine Journal 2007; 24, 614-617.
Knor J, Pokorna M. The importance of measurement of end-tidal CO2 in prehospital care. Presentation at the 11th World Congress of the Disaster and Emergency Medicine Federation, 2001.
Katz SH, Falk JL. Misplaced endotracheal tubes by paramedics in an urban emergency medical services system. Annals of Emergency Medicine 2001; 37(1), 32-37.
Sanders AB, Ewy GA, et al. Expired CO2 as a prognostic indicator of successful resuscitation from cardiac arrest. Ann Emerg Med 1985; 3(2), 147-149.
Callahan M, Barton C. Prediction of outcome of cardiopulmonary resuscitation from end-tidal carbon dioxide concentration. Crit Care Med 1990; 18(4), 358-362.
Grmec S, Klemen P. Does the end-tidal carbon dioxide concentration have prognostic value during out-of-hospital cardiac arrest? European J Emerg Med 2001; 8(4), 263-269.
Levine RL, Wayne MA, Miller CC. End-tidal carbon dioxide and outcome of out-of-hospital cardiac arrest. NEJM 1997; 337(5), 301-306.
Personal communication, Dr. Jeffrey Goodloe.
Genzwuerker HV. Unavailability of capnometry: a legal issue. Anesth Analg 2007, 105, 1167.
Vargese JH. Use of disposable end tidal carbon dioxide detector device for checking endotracheal tube placement. Journal of Clinical and Diagnostic Research (serial online) 2007, 1:204-209.
Srinivasa V, Kodali BS. Caution when using colorimetry to confirm endotracheal intubation. (Letter to the editor) Anesth Analg 2007; 104, 738.
Maleck WH, Koetter KP. Esophageal-tracheal Combitube. colorimetric carbon dioxide detection, and the esophageal detection device. Letter to the editor. Journal of Clinical Monitoring 1996; 12, 203-204.
Berlac PK, Hyldmo P, et al. Prehospital airway management: guidelines from a task force from the Scandinavian Society for Anaesthesiology and Intensive Care Medicine. Acta Anaesthesiol Scand 2008; 52: 897-907.
Stockinger ZT, McSwain NE, Jr. Prehospital endotracheal intubation for trauma does not improve survival over bag-valve-mask ventilation. Journal of Trauma-Injury Infection & Critical Care 2004; 56(3): 531-536.
Younquist ST, Henderson DP, et al. Paramedic self-sufficiency and skill retention in pediatric airway management. Acad. Emerg Med. 2008;15: 1-9.
Simpson HK, Smith GB. Survey of paramedic skills in the United Kingdom and Channel Islands. BMJ 1996; 313: 1052-1053.
US Bureau of Labor Statistics, 2009.
Braman SS, Dunn MD, et al. Complications of intrahospital transport in critically ill patients. Annals of Internal Medicine 1987; 107(4), 469-421.
Singh S, Allen WD Jr., et al. Utility of a novel quantitative handheld microstream capnometer during transport of critically ill children. Am J Emerg Med 2006, 24(3), 302-307.
Runcie CJ, Reeve W. Is portable capnometry useful during transport of the critically ill? Journal of Clinical Monitoring and Computing 1992;8(3), 1387-1307.
Bhende MA. End tidal monitoring in pediatrics – clinical applications. J Postgrad Med 2001; 47: 215.
Joldzo A, Bertalanffy P, et al. Capnometry in non-intubated emergency patients improves pre-hospital monitoring quality compared to pulse oximetry. Anesthesiology 2003; 99: A395.
Aufderheide TP, Lurie KG. Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med 2004; 32(9) Suppl, S345-S351.
Aufderheide TP, Sigurdsson G, et al. Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation 2004; 1960-1965.
Wayne MA, Delbridge TR, et al. Concepts and application of prehospital ventilation. Prehosp Emerg Care 2001; 5 (1), 73-78.
Warner KL, Bulger EM. Does pre-hospital ventilation affect outcome after significant brain injury? Trauma 2007; 9(4), 283-289.
Wang HE, Peitzman AB, et al. Out-of-hospital endotracheal intubation and outcome after traumatic brain injury. Ann Emerg Med. 2004; 44(5),439-450.
Warner KJ, Cuschieri J, et al. Emergency department ventilation effects outcome in severe traumatic brain injury. Journal of Trauma-Injury Infection & Critical Care 2008; 64(2), 341-347.
Davis DP, Ochs M, et al. Paramedic-administered neuromuscular blockade improves prehospital intubation success in severe head-injured patients. J Trauma 2003; 55:713-719.
Davis DP, Dunford JV, et al. The impact of hypoxia and hyperventilation on outcome after paramedic rapid sequence intubation of severely head-injured patients. Journal of Trauma 2004; 57(1), 1-10.
Poste JC, Davis DP, et al. Air medical transport of severely head-injured patients undergoing paramedic rapid sequence intubation. Air Med J 2003; 23: 36-40.
Sanders AB. Capnometry in Emergency Medicine. Ann Emerg Med 1989; 18(12), 1287-1290.
Cone DC, Cahill JC, Wayne MA. Cardiopulmonary resuscitation. In Gravenstein JS, ed. Capnography: Clinical Aspects 2004. Cambridge University Press.

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