cardiopulmonary resuscitation

Chapter 5 / Management of Ventilation 95

95

From: Contemporary Cardiology: Cardiopulmonary ResuscitationEdited by: J. P. Ornato and M. A. Peberdy © Humana Press Inc., Totowa, NJ

5 Management of VentilationDuring Resuscitation

Marsh Cuttino, MD

CONTENTS

INTRODUCTION

VENTILATION

INDICATIONS FOR ASSISTED VENTILATION

TECHNIQUE

VENTILATION VOLUME

INTERMEDIATE AIRWAY TECHNIQUES AND DEVICES

ADVANCED AIRWAYS

CONCLUSION

REFERENCES

INTRODUCTION

The decision to control a patient’s airway during cardiopulmonary resuscitation (CPR)is straightforward. Patients in cardiopulmonary arrest generally are totally unresponsive,and airway techniques can be used without the need for pharmacological adjuncts. Muchof the decision making relates to timing and the type of ventilation method to use. Thesedecisions are influenced by the patient’s oxygenation status, duration of arrest, expecteddifficulties with airway control, and operator experience and training.

VENTILATION

Establishing a secure patent airway is one of the primary tasks of the emergency careprovider during resuscitation. Adequate ventilation can reduce hypoxia and hypercapnea.The airway should be obtained as soon as possible during resuscitation. Failure to controlthe airway can have ominous consequences.

Endotracheal intubation is considered the optimal method for securing the airwaycurrently because it allows adequate ventilation, oxygenation, and airway protection.The Combitube (Kendall Healthcare Products, Mansfield, MA) and laryngeal mask air-way (LMA North America, San Diego, CA) are acceptable and possibly helpful alterna-tive airway devices.

The main advantages of alternative airway devices is that they (a) are generally easierto insert than an endotracheal tube (ETT); (b) may provide ventilation results similar to

96 Cardiopulmonary Resuscitation

that provided by endotracheal intubation and superior to bag-valve-mask ventilation; and(c) have similar complication rates to endotracheal intubation. Additionally, alternativeairway devices can sometimes be used when tracheal intubation is not possible (1).

The amount of ventilation required during resuscitation is not well established. Althoughthe minute ventilation requirements may be decreased by a low cardiac output, the excessload of carbon dioxide returning from ischemic tissue beds must be cleared by ventila-tion. Chest compressions alone do not generate adequate or consistent ventilation inhumans, even after intubation (2). In the resuscitation patient, 100% oxygen should bestarted immediately using a bag-valve-mask. This should be followed rapidly by endot-racheal intubation once skilled individuals arrive on scene. If intubation is unsuccessful,then an alternative airway should be employed.

When a nonintubated patient is ventilated, the distribution of gas between the lungsand stomach depends on the patient’s lower esophageal sphincter pressure, respiratorymechanics (the respiratory system compliance and degree of airway obstruction), and thetechnique of the rescuer performing basic life support (BLS; inspiratory flow rate, peakairway pressure, and tidal volume). Accidental stomach inflation during CPR can elevateintragastric pressure and lead to the cascade of regurgitation, aspiration, pneumonia, anddeath even in the successfully resuscitated patient (3).

Ventilation has an impact on blood gases even at very low cardiac output states (4).Hypoxia and hypercarbia have an independent adverse effect on resuscitation, and canbe corrected with appropriate ventilation. Adequate ventilation is important for return ofspontaneous circulation (5). Successful ventilation with rapid and uninterrupted chestcompressions significantly improves coronary perfusion during CPR (6) and this makessuccessful defibrillation more likely (7).

In cardiac arrest (CA) there is generally sufficient oxygenation in the blood that areasonable oxygen saturation persists for approx 5 minutes when there is adequate chestcompression (8). Bystander CPR for the first 5 minutes has equivalent outcomes with orwithout mouth-to-mouth ventilation (9). This suggests that airway control is most usefulwhen achieved in the first 5–6 minutes of CA.

INDICATIONS FOR ASSISTED VENTILATION

Rapid assessment of the patient allows for appropriate decision on airway manage-ment. Important considerations include adequacy of ventilation, airway patency, need forneuromuscular blockade, cervical spine stability, safety of the technique, and the skill ofthe operator (10).

Some patients are intubated for airway protection and others are intubated specificallyfor failure of ventilation or oxygenation. Objective indicators of ventilatory status includearterial blood gas, pulse oximetry, capnography, chest radiography, and spirometry. Meth-ods to maintain an open airway range from BLS measures (e.g., head tilt–chin lift) toadvanced airway techniques (e.g., endotracheal intubation). Medical providers should beproficient in several techniques at each level of airway control. This allows the operatorto be flexible in the management of the airway as the situation demands.

Once a patient has been found to be unresponsive, and the emergency response systemhas been activated, the airway needs to be assessed. First, the patient should be placed inthe supine position. If trauma is suspected, the cervical spine must be protected, and thepatient should be log rolled. The rescuer should open the airway and assess breathing bylooking for a chest rise, listening for exhaled breath, and feeling for air exchange at the


nose and mouth. If the airway and breathing are inadequate, the airway should be opened.In the unresponsive patient, the tongue and epiglottis may be obstructing the pharynx.

There are two techniques for opening an airway manually: the head tilt–chin lift andthe jaw thrust maneuver. In some patients, spontaneous breathing returns after the airwaybecomes patent. These patients should then be placed in a recovery position to reduce therisk of aspiration. The American Heart Association (AHA) Guidelines released in 2000for the recovery position include the following (11):

• Use a lateral position, with the head dependent to allow free fluid drainage.• Make sure position is stable.• Avoid pressure on the chest that impairs breathing.• Good observation and access to the airway should be possible.• The position should not give rise to injury to the patient.• It should be possible to return the patient to the supine position quickly and easily, and

maintain cervical stability.• Repositioning should occur to prevent prolonged time in one position.• Patient should be monitored until airway is definitively secured.

Head Tilt–Chin LiftPlacing one hand on the patient’s forehead and the index and middle finger of the other

hand on the bony part of the chin performs the head tilt–chin lift. The patient’s head isrotated as the chin is lifted. This lifts the jaw and elevates the tongue off the back of thepharynx, opening the airway.

Jaw Thrust

Grasping the angles of the jaw with the index and middle fingers and lifting with bothhands performs the jaw thrust. The head is maintained in the neutral position without anyflexion or extension. As the jaw is lifted, the patient’s mouth is opened with the thumbs.This is the preferred method when there is a possibility of cervical spine injury.

Basic Life Support Techniques

The first step is to open the airway, then look, listen, and feel for breathing. If thepatient is not breathing adequately, rescue breathing must be performed. The AHA rec-ommends that lay rescuers check for “signs of circulation” (e.g., normal breathing, cough-ing, or normal movement in response to stimulation) rather than perform a pulse checkto determine if chest compression’s should be administered. Trained health care provid-ers are encouraged to check for a pulse. Rescue breathing for both single rescuer CPR andmultiple rescuer CPR with an unprotected airway is at a 15:2 ratio of chest compressionto breathing with a rate of 100 compressions per minute (11).

Mouth-to-Mouth Ventilation and Variants

Rescue breathing through mouth-to-mouth ventilation has been an important part ofCPR for more than 30 years. Concern about transmission of infectious disease has madeboth professional medical providers and lay people reluctant to provide mouth-to-mouthventilation to adult strangers (12). This has led to consideration of removing mouth-to-mouth ventilation guidelines from CPR (9). Current guidelines still recommend mouth-to-mouth ventilation in out-of-hospital arrest, but recognize that basic CPR with chest


compression alone is still better than no CPR (13). All out of hospital pediatric arrestvictims should receive mouth-to-mouth ventilation, since most pediatric CA have a largerespiratory component (14).

TECHNIQUE

Mouth-to-mouth ventilation is the most basic form of positive pressure ventilation.The rescuer positions him or herself at the patient’s side. After opening the airway, therescuer takes a deep breath, pinches the patient’s nose, and seals his or her mouth aroundthe patient’s mouth. Slow deep breaths are delivered, and after each breath the mouth isremoved to allow passive exhalation. Using slow breaths helps prevent gastric inflationand aspiration from reflux and regurgitation.

Mouth-to-Nose Rescue Breathing

Mouth-to-nose rescue breathing can be used when there are contraindications to mouth-to-mouth breathing. Conditions such as anatomic abnormalities, trismus, or severe traumacould prevent formation of an appropriate seal. The rescuer positions the patient’s headin extension. One hand is placed on the forehead and the other lifts the mandible andcloses the mouth. The rescuer’s mouth is placed over the patient’s nose and a seal isformed with the lips. The appropriate breaths are delivered, and the mouth is removedfrom the patient’s nose to allow passive exhalation. It may be necessary to open the mouthintermittently to allow complete exhalation.

Mouth-to-Shield Ventilation

Face shields are small, disposable, plastic barrier devices that can be used duringmouth-to-mouth ventilation. This removes any concern over infectious disease transmis-sion. Shields may have enhancements such as one-way valves. The rescuer positions theshield on the patient, pinches the nose and seals his or her mouth around the centeropening of the face shield. After the appropriate breaths are delivered, the rescuer lifts hisor her mouth from the shield and allows the patient to exhale. Figure 1 shows an exampleof a pocket shield device. There are numerous other examples available on the marketwith similar function.

Mouth-to-Mask Method

Another technique designed to isolate the rescuer from the patient is the mouth-to-mask method. A standard face mask is used and fitted over the mouth using the sameposition as used for the bag-valve-mask (Fig. 2). The rescuer can provide rescue breathseither into the mask directly or indirectly using a one-way valve adapter. When theadapter is used the face mask must be released to allow exhalation.

VENTILATION VOLUME

Mouth-to-mouth ventilation with a tidal volume of 1000 mL contains about 17%oxygen and about 4% carbon dioxide (15). The gas composition can be improved to about19% oxygen and 2–3% carbon dioxide by taking a deep breath and exhaling only about500 mL (16). With normal cardiac output, tidal volumes of 800–1000 mL are requiredto maintain adequate oxygenation (17,18). Some authors have suggested that because


Fig. 1. Example of a pocket shield device.

\

Fig. 2. Ventilation masks.

cardiac output is reduced to at best 20–30% of normal during CPR there is a reducedrequirement for ventilation (19,20). It appears that a tidal volume of 500 mL may beadequate during CPR when supplemental oxygen is added (21). Current guidelines rec-ommend a tidal volume of 10 mL/kg or 700 to 1000 mL over 2 seconds (13).


INTERMEDIATE AIRWAY TECHNIQUES AND DEVICES

Bag-Valve-Mask DeviceThe bag-valve-mask is a common device for delivering positive pressure ventilation

in the initial stages of resuscitation (Fig. 3). The key to proper use of the bag-valve-maskis to maintain a tight seal. There are different techniques depending on whether there isa single operator or two operators.

TechniquesSINGLE OPERATOR

The rescuer stands at the head of the patient. The mask is applied to the patient’s facewith one hand. The thumb and index fingers secure the mask, and the remaining fingersare placed over the bony portion of the mandible. As the rescuer ventilates the patient,the fingers on the mandible maintain the head tilt and jaw thrust to keep the airway patentand the mask snug against the face.

DUAL OPERATORS

The first rescuer stands at the head of the patient. The mask is applied to the patient’sface, and the thumb and index fingers of both hands secure the mask and maintain a goodseal. The remaining fingers are used on the bony portion of the mandible to maintain thehead tilt and jaw thrust. The second rescuer stands to the right of the patient, and providestwo-handed compression of the bag to ventilate the patient (Fig. 4).

Oropharyngeal Airway DeviceAn oropharyngeal airway is a plastic or rubber device that can be inserted into a victim’s

mouth to elevate the tongue and create a path between the tongue and palate (Fig. 5). Thisdevice should not be used on a patient who has an intact gag reflex. It is indicated in theunresponsive or obtunded patient and can be used in conjunction with a bag-valve-maskdevice.

To size an oropharyngeal airway, choose one that fits from the middle of the mouth tothe angle of the jaw. The airway is inserted by turning it 90° and inserting it halfway intothe mouth. Then rotate back 90° so that the bottom wraps around the back of the tongue.

Fig. 3. Example of a typical bag-valve-mask assembly.


Fig. 4. Two-person bag-valve-mask technique. Note the set of hands on the bottom left maintain-ing in-line cervical stabilization.

Fig. 5. Oropharyngeal airways.

The distal portion of the airway should remain outside of the mouth to ensure that it doesnot become an airway obstruction.

If the patient begins to gag, the oropharyngeal airway should be pulled out. Theoropharyngeal airway may be contraindicated in facial or mandibular trauma patients.This airway will not maintain a patent airway if the patient has incorrect head placement.


Nasopharyngeal Airway DeviceA flexible tube designed to be inserted into the nares and extend to the base of the

tongue (Fig. 6). A nasopharyngeal airway can help maintain airway patency in an uncon-scious or obtunded patient but does not ensure patency without good head positioning.This airway adjunct can be used in conjunction with a bag-valve-mask to facilitate ven-tilation. Nasopharyngeal airways can be used with patients that still have an intact gagreflex.

To size a nasopharyngeal airway, choose a tube that extends from the tip of the noseto the angle of the patient’s mandible. The diameter of the tube should approximate thediameter of the nares. The tube is lubricated and inserted into the nares so that the beveledtip is midline, and the curve of the tube follows the curvature of the patient’s airway.

ADVANCED AIRWAYSOrotracheal Intubation

The most common technique of advanced airway control is orotracheal intubationwith direct visualization laryngoscopy. Laryngoscopes are used to provide a direct viewof the vocal cords and facilitate placement of the ETT. Most intubations during CPRare “crash” airways and do not require pharmacologic adjuncts such as rapid sequenceinduction.

Fig. 6. Nasopharyngeal airways.


The laryngoscope is an apparatus designed to permit direct visualization of the larynxand facilitate endotracheal intubation through direct laryngoscopy (Figs. 7 and 8). Thereare two basic blade designs. The first is the curved blade, typified by the MacIntosh blade.The second type is the straight blade such as the Miller or Wisconsin blades (Welch Allyn,Skaneateles Falls, NY). Various sizes are available for adult and pediatric use. The main

Fig. 7. Examples of laryngoscope handles and blades.

Fig. 8. Miller and MacIntosh laryngoscope blades.


difference in the usage of the blades regards the epiglottis. A straight blade lifts theepiglottis directly, but the curved blade tip fits in the vallecula and indirectly lifts theepiglottis.

The choice of which blade to use should be based on the patient’s clinical history.Straight blades are better for pediatric patients, patients with an anterior larynx,patients with a long floppy epiglottis, or patients with a scarred epiglottis. Straightblades allow for more control of the airway in trauma patients, and may offer someadvantages when there is debris in the airway. There are several disadvantages withstraight blades. They are hard to use with large teeth, and may be more likely to breakteeth than their curved counterparts. Straight blades can stimulate the superior laryn-geal nerve and lead to laryngospasm. These blades can be inserted inadvertently intothe esophagus and lead to esophageal intubation. Curved blades offer better control ofthe tongue can allow more room in the hypopharynx to pass the endotracheal tube.Curved blades possibly require less forearm strength to use. Medical providers withless experience frequently prefer curved blades as they can provide a superior viewwith less provider effort.

Endotracheal TubesThe standard endotracheal tube is plastic and about 30 cm in length (Fig. 9). The tube

size is measured based on the internal diameter in millimeters. An adult male usuallyrequires a 7.5–9.0 mm ETT, however women can usually be intubated with a 7.0–8.0 mmtube. The best time to intubate a patient during resuscitation is often described as “as soonas physically possible.” Animal models of out-of-hospital arrest suggest that the defini-

Fig. 9. Endotracheal tubes.


tive airway can be delayed for 5–6 minutes without decreasing the likelihood of sponta-neous return of circulation (5).

TechniquePREPARE EQUIPMENT

1. Check suctioning equipment.2. Inflate and deflate the endotracheal tube balloon to check for leaks.3. Connect laryngoscope blade to the handle to check bulb function.

POSITION

1. Place the patient’s head in the sniffing position if no evidence of trauma.2. If trauma is suspected, maintain in-line cervical stabilization in the neutral position.3. Preoxygenate.4. Maximize oxygen saturation by administering 100% O2 preferably by face mask or bag-

valve-mask.5. Pass the tube.6. Holding the laryngoscope in the left hand, insert the laryngoscope into the right side

of the mouth and sweep the tongue to the left. Advance the blade and visualize theepiglottis and vocal cords. Insert the endotracheal tube through the vocal cords. Inflatethe balloon.

PLACEMENT

Check for tube placement by auscultating over the chest and abdomen. If capnometryor capnography is available, it can be used to confirm placement. Capnometry (colori-metric, analog, or digital) can yield false negative results during low-flow states such asduring resuscitation. Capnography remains accurate in determining endotracheal tubeplacement even in the presence of a low-flow state. An alternate method to confirm ETTplacement is to use an esophageal detector suction device. When time allows, obtain achest x-ray to confirm endotracheal tube location.

DEVICES FOR CONFIRMATION OF ENDOTRACHEAL TUBE PLACEMENT

There are numerous devices that can be utilized to confirm the proper placement of anETT. A detailed examination of placement confirmation devices is beyond the scope ofthis chapter.

Capnography uses a chemical paper to rapidly determine the presence of carbon diox-ide in exhaled air. This is a qualitative, not quantitative device. A change in color suggeststracheal intubation (Fig. 10).

To use the bulb suction device, first deflate the bulb with the thumb and then place thedevice securely on the ETT connector (Fig. 11). The bulb is released, and if the endot-racheal tube is inserted in the esophagus the suction of the bulb collapses the flexibletissue of the esophagus and the bulb does not inflate. With proper placement the rigidstructures of the trachea do not collapse and the bulb rapidly inflates. Rapid bulb inflationconfirms tracheal intubation.

A similar technique is used with the syringe aspiration test (Fig. 12). Instead of bulbinflation, the syringe is attached and the plunger rapidly drawn back by the provider.Increased resistance suggests esophageal intubation.

These confirmation techniques have the advantage that they can be utilized in highnoise environments or in situations in which stethoscopes are unavailable or unusable,such as during a disaster.


Fig. 10. Example of a capnograph.

Fig. 11. Bulb esophageal detector.

Endotrol Endotracheal TubeNasotracheal intubation is an alternative technique in which the ETT or Endotrol tube

(Mallinckrodt Critical Care Inc., St. Louis, MO) is inserted through the nares down intothe trachea. The Endotrol tube is an ETT with a loop attached that increases the curvatureof the tip when pulled. The Endotrol is used during nasogastric intubation. Usually thetube size chosen is slightly smaller (by 0.5–1.0 mm) than would be used for endotrachealintubation. As nasotracheal intubation requires that the patient be spontaneously breath-ing, it will not be considered further in this chapter.


CombitubeThe Combitube is a double lumen tube with two balloons (Fig. 13). It is designed for

blind insertion during emergency situations and difficult airways. The esophageal obtu-rator tube is sealed at the distal end, and has perforations at the pharyngeal level. Thetracheal tube has a clear distal opening. The large upper oropharyngeal balloon serves toseal off the mouth and nose. The distal cuff balloon seals off either the trachea or theesophagus.

One advantage of the Combitube is that insertion requires less skill than direct laryn-goscopy. Because it can be inserted blindly, it can be used under difficult lighting andspace restrictions. It is very useful when visualization of the vocal cords is impossible.

Fig. 12. Syringe aspirator.

Fig. 13. Combitubes.


Contraindications include patients with intact gag reflexes, patient height less than 4 feet,a history of known esophageal pathology, a recent history of ingestion of caustic sub-stances, or central airway obstruction.

TECHNIQUE

To insert a Combitube, grasp the back of the tongue and jaw between the thumb andindex finger and lift. Insert the Combitube in a curved downward motion. Insertionshould not require any force by the operator. Inflate the oropharyngeal balloon first withbetween 85 and 100 cc of air (depending on the size of the Combitube) then inflate thedistal balloon with 5–15 cc of air.

The most likely result of a blind intubation is esophageal intubation. Attempt venti-lation through the longer blue tube. If breath sounds are present then the tip of theCombitube is in the esophagus. If breath sounds are absent, then the tip of the tube is inthe trachea. If the tube has entered the trachea, ventilation is performed using the distallumen just like a standard endotracheal tube. Tracheal intubation can be achieved byusing a laryngoscope in conjunction with a Combitube.

Laryngeal Mask AirwayThe LMA was introduced into clinical practice in 1988. The LMA is a triangular

shaped inflatable pink silicon laryngeal mask (Fig. 14). The mask has an opening in themiddle that prevents accidental obstruction of the tube by the tip of the epiglottis. Gastricdistention is minimized because excess pressure is vented upward around the LMAinstead of into the esophagus.

The LMA can be used when the patient is unresponsive or the protective reflexes havebeen sufficiently depressed. The mask is deflated to form a flat wedge that will passbehind the tongue and behind the epiglottis. The LMA is blindly inserted into the pharynxwith the point of the triangle in the esophagus and the mask over the laryngeal inlet. Themask is then inflated and seals off the laryngeal inlet. The LMA is not a definitive airway,and provides almost no prevention of aspiration of stomach contents from below or bloodand secretions from above. The LMA is best for providers not trained in endotrachealintubation. It can be used as an adjunct in the difficult airway when primary endotrachealintubation has been attempted unsuccessfully.

TECHNIQUE

Completely deflate the LMA until the cuff forms a smooth spoon shape without anywrinkles. Hold the LMA like a pen, with the mask facing forward and the black line onthe tube oriented toward the upper lip. Insert the mask with the tip of the cuff up towardthe hard palate. The index finger can be used to assist in guiding the LMA behind thetongue. Advance the LMA into the hypopharynx until resistance is felt. Inflate the cuffwith enough air to obtain a seal. Normal intracuff pressures are around 60 cm H2O.

CONCLUSION

Providers should be familiar with BLS techniques in addition to advanced airway tech-niques. The patient’s airway should be secured definitively within the first 5–6 minutes ofCPR. This allows for adequate ventilation, and increases the possibility of return of spon-taneous circulation. Endotracheal intubation is the method most commonly used to securethe airway. Alternative methods include the Combitube and LMA. The position of anadvanced airway should be confirmed with capnography or an esophageal detector device.


REFERENCES

1. Barnes T, Macdonald D, Nolan J, et al. Cardiopulmonary resuscitation and emergency cardiovascularcare. Airway devices. Ann Emerg Med 2001; 37:S145–S151.

2. Neumar R, Ward K. Adult Resuscitation. In: Rosen’s Emergency Medicine: Concepts and ClinicalPractice, J. Marx, ed. St. Louis, MO: Mosby, 2002.

3. Wenzel V, Idris AH, Montgomery WH, et al. Rescue breathing and bag-mask ventilation. Ann EmergMed 2001; 37:S36–S40.

4. Idris AH, Banner MJ, Wenzel V, Fuerst RS, Becker LB, Melker RJ. Effect of ventilation on acid-basebalance and oxygenation in low blood-flow states. Crit Care Med 1994; 22:1827–1834.

5. Idris A. Does hypoxia or hypercarbia independently affect resuscitation from cardiac arrest? Chest 1995;108:522–8.

6. Feneley M, Maier GW, Kern KB, et al. Influence of compression rate on initial success of resuscitationand 24 hour survival after prolonged manual cardiopulmonary resuscitation in dogs. Circulation 1988;77:240–250.

7. Sato Y, Weil MH, Sun S, et al. Adverse effects of interrupting precordial compression during cardiop-ulmonary resuscitation. Crit Care Med 1997; 25:733–736.

8. Chandra N. Observations of Ventilation during resuscitation in a canine model. Circulation 1994;90:3070–5.

9. Kern K. Cardiopulmonary resuscitation without ventilation. Crit Care Med 2000; 28(Suppl):N186–9.10. Clinton J, McGill J. Basic Airway Management and Decision Making, in Clinical Procedures in Emer-

gency Medicine, Roberts JR, Hedges JR, Eds. Philadelphia: W.B. Saunders Co., 1998.11. Pepe P, Gay M, Cobb LA, et al. Action sequence for layperson cardiopulmonary resuscitation. Ann

Emerg Med 2001; 374 (Suppl):S17–25 (suppl).12. Ornato J, Hallagan LF, McMahan SB, Peeples EH, Rostafinski AG. Attitudes of BCLS instructors about

mouth-to-mouth resuscitation during the AIDS epidemic. Ann Emerg Med 1990; 19:151–156.13. Stapleton E. Basic life support cardiopulmonary resuscitation. Cardiol Clin 2002; 20:1–12.14. Berg R, Hilwig RW, Kern KB, Babar I, Ewy GA. Simulated mouth-to-mouth ventilation and chest

compression (bystander cardiopulmonary resuscitation) improves outcome in a swine model of out-of-hospital pediatric asphyxial cardiac arrest. Crit Care Med 1999; 27:1893–1899.

15. Wenzel V, Idris A, Banner M. The composition of gas given by mouth-to-mouth ventilation during CPR.Chest 1994; 106:1806–1810.

16. Htin K, Birenbeaum DS, Idris AH, Banner MJ, Gravenstein N. Rescuer breathing pattern significantlyaffects O2 and CO2 received by the patient during mouth-to-mouth ventilation. Crit Care Med 1998;26(Suppl 1):A56.

Fig. 14. Laryngeal mask airway.


17. Dorges V, Ocker H, Hagelberg S, Wenzel V, Schumucker P. Optimisation of tidal volumes given withself-inflatable bags without additional oxygen. Resuscitation 2000; 43:195–199.

18. Stallinger A, Wenzel V, Oroszy S, et al. The effects of different mouth-to-mouth ventilation tidalvolumes on gas exchange during simulated rescue breathing. Anesth Analg 2001; 93(5):1265–9.

19. Weil MH, Rackow EC, Trevino R, Grundler W, Falk JL, Griffel MI. Differences in acid-base state betweenvenous and arterial blood during cardiopulmonary resuscitation. N Engl J Med 1986; 315:153–156.

20. Sanders A, Otto CW, Kern KB, Rogers JN, Perrault P, Ewy GA. Acid-base balance in a canine modelof cardiac arrest. Ann Emerg Med 1988; 17:667–671.

21. Idris A. Effects of inspired gas content during respiratory arrest and cardiopulmonary resuscitation. CritCare Med 2000; 28(11 Suppl):N196–198.

cardiopulmonary resuscitation

Documents