WEBVTT 1 00:00:12.320 --> 00:00:18.880 One tidal volume of 180 milliliters will occur when the chin is pulled up. 2 00:00:24.420 --> 00:00:25.560 Chin up. 3 00:00:27.180 --> 00:00:27.980 Here. 4 00:00:35.900 --> 00:00:41.220 Notice the chest motion which indicates a patent airway when positive pressure is 5 00:00:41.220 --> 00:00:42.260 applied from above. 6 00:00:45.660 --> 00:00:51.420 Now we will study the currently taught back pressure arm lift method, also 7 00:00:51.420 --> 00:00:56.640 called Holger Nielsen method. The subject is turned into the prone position. The 8 00:00:56.640 --> 00:01:01.300 face mask which we are using is a special flat mask. A conventional 9 00:01:01.300 --> 00:01:06.140 anesthesia mask would protrude and interfere with the natural position of 10 00:01:06.140 --> 00:01:12.580 the head when the subject is lying prone. Now the rescue is performing the back 11 00:01:12.580 --> 00:01:18.940 pressure arm lift method as it was taught since 1951. Namely, the subject's 12 00:01:18.940 --> 00:01:25.480 head is turned to the side and his hands are placed under his cheek. An artificial 13 00:01:25.480 --> 00:01:30.560 oropharyngeal airway is in place which prevents obstruction by the lips and 14 00:01:30.560 --> 00:01:33.520 teeth and holds the tongue forward. 15 00:01:39.260 --> 00:01:45.840 The spirometer shows that all tidal volumes are smaller than 50 milliliters. 16 00:01:46.600 --> 00:01:56.020 This means no air reaches the alveoli. Notice how each arm lift maneuver pulls 17 00:01:56.020 --> 00:02:02.880 the subject's body towards his head, thus increasing the flexion and torsion of 18 00:02:02.880 --> 00:02:10.600 the neck. This is an enlarged copy of the spirometer tracing which you have just 19 00:02:10.600 --> 00:02:19.320 seen. All tracings you will see are read from the right to the left. Note that 20 00:02:19.320 --> 00:02:26.960 there is almost zero exchange and air is squeezed out of the lungs. Now we will 21 00:02:26.960 --> 00:02:33.960 extend the neck so that the chin rests over the hands. Again the spirometer 22 00:02:33.960 --> 00:02:37.360 shows no air exchange. 23 00:02:40.600 --> 00:02:45.620 In some volunteers this extension of the neck improved the initial tidal exchange 24 00:02:45.620 --> 00:02:51.280 significantly. However, the head moved back spontaneously into the flexed and 25 00:02:51.280 --> 00:02:59.620 twisted position as you see here and caused progressive obstruction. A second 26 00:02:59.620 --> 00:03:03.960 rescue attempting to hold the head and jaw interfered thereby with the 27 00:03:03.960 --> 00:03:09.740 performance of the main rescuer. The subject will be turned on his back for 28 00:03:09.740 --> 00:03:11.260 hyperoxygenation. 29 00:03:24.260 --> 00:03:29.120 Hyperoxygenation can best be performed in the supine position. In the prone 30 00:03:29.120 --> 00:03:34.380 position the face is fully accessible which makes jaw support and mask fit 31 00:03:34.380 --> 00:03:35.420 almost impossible. 32 00:03:39.100 --> 00:03:43.920 Here the trachea is intubated and the subject is again ready for the 33 00:03:43.920 --> 00:03:48.660 performance of the back pressure arm lift method. This time with an endotracheal 34 00:03:48.660 --> 00:03:54.220 tube in place which bypasses the pharyngeal area thus eliminating airway 35 00:03:54.220 --> 00:03:54.680 obstruction. 36 00:04:10.080 --> 00:04:12.540 Observe the movements of the ink writer. 37 00:04:16.700 --> 00:04:24.100 They indicate throughout tidal volumes of 400 to 500 milliliters. The main factor 38 00:04:24.100 --> 00:04:29.940 limiting air movements now is not airway obstruction but the distensibility of 39 00:04:29.940 --> 00:04:35.340 the subjects lungs and chest also called lung chest compliance. In this 40 00:04:35.340 --> 00:04:39.740 volunteer the compliance was measured to be approximately 50 milliliters per 41 00:04:39.740 --> 00:04:44.600 centimeter of water pressure for 1000 milliliters inflation. Lung chest 42 00:04:44.600 --> 00:04:48.860 compliance is reduced in obese subjects and in subjects with pulmonary disease. 43 00:04:50.420 --> 00:04:54.280 In the six subjects we have studied with the back pressure arm lift method and 44 00:04:54.280 --> 00:04:59.940 an endotracheal tube in place we obtain tidal volumes between 260 and 840 45 00:04:59.940 --> 00:05:05.880 milliliters. The low values in heavy subjects the high values in lean subjects. 46 00:05:07.460 --> 00:05:13.920 You have seen that the principal cause of the failure of the back pressure arm 47 00:05:13.920 --> 00:05:21.560 lift method is airway obstruction due to malpositioning of the head and mandible. 48 00:05:22.460 --> 00:05:32.820 We observed three types of obstruction. First complete obstruction. Second 49 00:05:32.820 --> 00:05:38.060 inspiratory obstruction only which is caused by a valve-like behavior of the 50 00:05:38.060 --> 00:05:44.780 pharynx. The back pressure squeezes air out of the lungs succeeding arm lift 51 00:05:44.780 --> 00:05:54.980 maneuvers need inspiratory obstruction. And third progressive obstruction. Here 52 00:05:54.980 --> 00:06:00.540 the airway was open in the beginning and succeeding arm lift maneuvers caused 53 00:06:00.540 --> 00:06:08.060 flexion of the neck and zero exchange. Now I will summarize all tidal volumes 54 00:06:08.060 --> 00:06:13.520 measured during performance of the back pressure arm lift method in all 15 55 00:06:13.520 --> 00:06:20.120 subjects studied. When it was performed as taught since 1951 the average tidal 56 00:06:20.120 --> 00:06:29.000 volume was 126 milliliters ranging from 0 to 780 milliliters. Insertion of an 57 00:06:29.000 --> 00:06:34.100 artificial or a pharyngeal airway produced only insignificant improvement. 58 00:06:35.620 --> 00:06:42.120 An average of 177 milliliters. When the subject's head was placed in extension at 59 00:06:42.120 --> 00:06:49.200 the beginning the average tidal volume was 520 milliliters ranging from 0 to 60 00:06:49.200 --> 00:06:56.620 1160. Within a nutritional tube the average tidal volume was 566 milliliters. 61 00:06:57.560 --> 00:07:02.640 May I point out here however that all these volumes must be considered 62 00:07:02.640 --> 00:07:09.660 borderline volumes. A method which moves only 500 milliliters under ideal 63 00:07:09.660 --> 00:07:16.760 experimental conditions will often not be able to overcome in actual asphyxia 64 00:07:16.760 --> 00:07:24.360 victims airway obstruction due to mucus, vomitus, blood or other foreign matter. 65 00:07:25.080 --> 00:07:30.000 Intermittent positive pressure breathing such as mouth-to-mouth breathing moved 66 00:07:30.000 --> 00:07:37.260 in all our subjects tidal volumes between 1,000 and 3,000 milliliters. 67 00:07:38.120 --> 00:07:42.440 Before studying mouth-to-mouth breathing we calibrate the pneumograph with lung 68 00:07:42.440 --> 00:07:49.040 inflations of 500, 1,000 and 2,000 milliliters. Here 1,000 milliliters of 69 00:07:49.040 --> 00:07:52.780 air are drawn through a gas meter into a bellows and pushed into the lungs 70 00:07:52.780 --> 00:07:57.240 through a tight fitting face mask and an artificial airway. The deflection of the 71 00:07:57.240 --> 00:08:00.900 recording the right upper corner indicates 1,000 milliliters. Now 72 00:08:00.900 --> 00:08:03.100 inflation with 2,000 milliliters. 73 00:08:11.700 --> 00:08:18.080 We made three inflations with each volume. The red arrow is mounted on the 74 00:08:18.080 --> 00:08:23.620 recording arm to make it visible on the screen. In the other experiments we 75 00:08:23.620 --> 00:08:29.120 obtained a recording such as this one during mouth-to-mouth breathing. Whenever 76 00:08:29.120 --> 00:08:34.900 the recorder of the pneumograph will not return to zero during expiration it is 77 00:08:35.120 --> 00:08:41.820 due to air blown into the stomach. When this occurs it is advisable to recalibrate. 78 00:08:43.520 --> 00:08:49.220 We were able in actual resuscitations to remove mucus, foam, vomitus or blood from 79 00:08:49.220 --> 00:08:54.040 the pharynx by forcing the victim's mouth open turning the head to the side 80 00:08:54.040 --> 00:09:05.100 and wiping mouth and pharynx clean with the fingers or a piece of cloth. Now you 81 00:09:05.100 --> 00:09:12.180 We call it the thumb jaw lift method. Note the hand positions. The right hand 82 00:09:12.180 --> 00:09:19.220 pinches the nostrils. The thumb of the left hand is inserted between the teeth. 83 00:09:27.880 --> 00:09:31.580 The mandible is grasped at the midline with the left hand and pulled forcefully 84 00:09:31.580 --> 00:09:41.340 upward. The pneumograph shows tidal volumes of 2,000 milliliters and more. 85 00:09:54.630 --> 00:10:10.790 Technical details are of extreme importance. Dropping the mandible as you see here obstructs 86 00:10:10.790 --> 00:10:22.310 pharynx and prevents inflation. No exchange. Chin up. Correct technique. Good 87 00:10:22.310 --> 00:10:35.490 exchange. This is another mistake. The rescuer forgot to pinch the nostrils. Now 88 00:10:35.490 --> 00:10:43.010 you will see a finicky mouth-to-mouth contact. A mistake often made by female rescuers. 89 00:10:50.350 --> 00:11:01.290 Here. The rescuer must open his mouth widely to cover the entire mouth of the victim plus 90 00:11:01.290 --> 00:11:16.570 the rescuer's own thumb to produce an airtight seal. Now comes the alternate method or two 91 00:11:16.570 --> 00:11:25.110 hands jaw lift method. Both hands grasp the angles of the mandible and pull forcefully 92 00:11:25.110 --> 00:11:33.910 upward. The thumbs retract the lower lip to prevent obstruction by the lips. Air leakage 93 00:11:33.910 --> 00:11:44.750 through the nostrils is prevented by the rescuer's right cheek. This method we recommend for using 94 00:11:44.750 --> 00:11:51.870 victims in whom the thumb cannot be inserted because the mouth is tightly closed. It also is 95 00:11:52.160 --> 00:11:58.360 a method of choice for infants in whose small mouths the rescuer's thumb would occupy too much 96 00:11:58.360 --> 00:12:09.620 space. In infants, the rescuer's mouth covers the mouth and nose of the victim. Here again the same 97 00:12:09.620 --> 00:12:22.460 mistake. Chin down, pull exchange, chin up. Good exchange. Lip obstruction, as you see here, 98 00:12:23.300 --> 00:12:33.700 can also lead to failure of the method. No lip retraction, no exchange. Watch the thumbs. Lip 99 00:12:33.700 --> 00:12:45.200 retraction, good exchange. Mouth to nose breathing often produced much smaller tidal volumes than 100 00:12:45.200 --> 00:12:51.420 mouth to mouth breathing because of greater airway resistance. Mouth to nose breathing sometimes 101 00:12:51.420 --> 00:12:57.780 met complete obstruction due to nasal congestion and mucus particularly towards the end of the 102 00:12:57.780 --> 00:13:06.580 mouth to nose breathing also proved to be less acceptable than mouth to mouth breathing. 103 00:13:10.820 --> 00:13:16.160 The following mouth to mouth methods proved ineffective in the hands of lay rescuers. This 104 00:13:16.160 --> 00:13:21.720 is the first poor method. The right hand closes the nostrils, the left hand supports the right 105 00:13:21.720 --> 00:13:31.560 angle of the mandible. Lay rescuers were unable to support adequately the mandible with one hand 106 00:13:31.560 --> 00:13:38.240 only at the angle of the mandible. Also there is obstruction by the lips and teeth. The second 107 00:13:38.240 --> 00:13:44.680 poor method. Both thumbs pinch the nostrils, the other fingers hold both angles of the mandible. 108 00:13:47.260 --> 00:13:50.020 Obstruction by the lips is not prevented. 109 00:13:55.500 --> 00:13:58.380 Here reoxygenation by the correct mouth to mouth method. 110 00:14:03.440 --> 00:14:09.500 The third poor method. The right hand pinches the nose and the left hand supports the angle 111 00:14:09.500 --> 00:14:19.460 of the jaw. Again inadequate jaw support and lip obstruction caused failure. When laymen placed 112 00:14:19.460 --> 00:14:27.280 one hand over the stomach to prevent gastric distension the jaw was poorly supported and the 113 00:14:27.660 --> 00:14:39.300 failed. The fourth method which proved insatisfactory. For aesthetic reasons the 114 00:14:39.300 --> 00:14:44.760 rescue interposed his thumb and index finger in form of a ring between the victim's mouth and 115 00:14:44.760 --> 00:14:57.480 his own mouth. Air leakage and obstruction by the lips caused failure. No exchange. 116 00:15:01.160 --> 00:15:06.880 Last poor method. The rescuer tried to keep the victim's mouth open by pressing from the outside 117 00:15:06.880 --> 00:15:11.980 against his cheeks. It proved difficult to locate the area on which pressure could be 118 00:15:11.980 --> 00:15:19.980 successfully applied. This S-shaped breathing tube, also called mouth-to-mouth airway, made 119 00:15:19.980 --> 00:15:26.140 mouth-to-mouth breathing more aesthetic and more effective. The large airway for use in adults and 120 00:15:26.360 --> 00:15:34.500 children. The small airway for use in children and infants. The end which remains outside is 121 00:15:34.500 --> 00:15:42.840 the mouthpiece for the rescuer. First the airway is inserted. One hand forces the mouth open, 122 00:15:43.360 --> 00:15:49.180 the other hand inserts the airway over the tongue taking care not to push the tongue back into the 123 00:15:51.220 --> 00:15:56.980 The rescue prevents air leakage through the nose and the corners of the mouth. Either this way, 124 00:16:02.060 --> 00:16:03.340 or this way, 125 00:16:11.420 --> 00:16:13.300 or this way. 126 00:16:18.160 --> 00:16:24.280 We demonstrate once more insertion of the airway. The tongue may be held forward during insertion 127 00:16:24.280 --> 00:16:34.800 by one finger. Correct position of the hands, deep inflations. In spite of the use of the 128 00:16:34.800 --> 00:16:39.320 artificial oropharyngeal airway, the head must be held in extension at all times. 129 00:16:48.160 --> 00:16:52.840 The flange must be pressed over the lips, the nostrils must be occluded, 130 00:16:56.040 --> 00:17:04.900 and the head must be held in extension. Forceful blowing is necessary 131 00:17:08.420 --> 00:17:16.500 for resuscitation of adults, gentle inflation in children. Here again chin down, no exchange. 132 00:17:19.760 --> 00:17:34.540 Chin up, good exchange. Here the airway is not inserted deep enough, full chest motion. 133 00:17:34.540 --> 00:17:44.260 Correct insertion, good chest motion. This is mouth to mask breathing. First a conventional 134 00:17:44.260 --> 00:17:49.140 oropharyngeal airway is inserted in the same way the mouth to mouth airway was inserted. 135 00:17:51.820 --> 00:17:57.640 The mask is held firmly over the victim's face. An airway under the mask is essential 136 00:17:57.640 --> 00:18:03.740 to prevent obstruction by the lips. Again the head must be held in extension. 137 00:18:08.580 --> 00:18:13.580 Now we permit the subject to recover temporarily by discontinuing the succinylcholine infusion. 138 00:18:14.360 --> 00:18:22.100 He now breathes spontaneously but very shallowly. Mouth to mouth assisted breathing. 139 00:18:24.040 --> 00:18:27.000 Limb movements return. 140 00:18:30.380 --> 00:18:31.660 Shallow spontaneous breaths. 141 00:18:38.020 --> 00:18:46.080 The assisted inflations must coincide with the subject's spontaneous inspiratory efforts. 142 00:18:53.280 --> 00:18:59.860 Here assisted breathing is performed by the mouth to airway method. The mouth to mouth airway was 143 00:18:59.860 --> 00:19:06.360 also used to provide airway patency in unconscious persons who were breathing spontaneously. The 144 00:19:06.360 --> 00:19:12.080 airway should be left in place until the victim is sufficiently recovered to expel the airway or to 145 00:19:12.080 --> 00:19:18.760 react by retching or coughing. The subject will be rendered again apneic by succinylcholine. 146 00:19:22.420 --> 00:19:28.980 We studied the performance of portable resuscitation equipment in the hands of 147 00:19:28.980 --> 00:19:38.220 untrained rescuers. They performed on paralyzed volunteers. We used a bag mask unit with a source 148 00:19:38.220 --> 00:19:53.740 of oxygen, a bellows and a mechanical resuscitator. During the first 60 seconds, 149 00:19:54.800 --> 00:19:59.960 less ventilation than with mouth to mouth breathing or no ventilation was produced with 150 00:19:59.960 --> 00:20:07.520 some of this equipment. This was due to difficulty in maintaining a patent airway and a tight mask 151 00:20:07.520 --> 00:20:14.480 fit and due to a delay in getting the equipment set up. Mouth to mouth breathing therefore should 152 00:20:14.480 --> 00:20:22.440 be started immediately when the victim is found while waiting for equipment. Oxygen resuscitation 153 00:20:22.440 --> 00:20:31.740 equipment should be used when it arrives. If the rescuer knows how to use it and knows how to 154 00:20:31.740 --> 00:20:39.160 maintain a patent airway and a tight mask fit, this boy scout will perform mouth to airway breathing. 155 00:20:40.000 --> 00:20:50.300 He weighs 100 pounds. He has some difficulty but corrects himself. He was able to adequately 156 00:20:50.300 --> 00:21:04.620 ventilate subjects weighing up to 210 pounds. This is a firefighter performing mouth to airway breathing. 157 00:21:05.720 --> 00:21:12.180 87 untrained rescuers performed mouth to airway breathing. All produced breaths larger than 500 158 00:21:12.180 --> 00:21:18.320 milliliters within 60 seconds after one demonstration. All could insert the airway within 40 seconds. 159 00:21:18.320 --> 00:21:23.080 Although 50 percent of them had never inserted an artificial airway before. 160 00:21:28.540 --> 00:21:36.820 The 167 untrained rescuers who performed mouth to mouth breathing on paralyzed volunteers consisted 161 00:21:36.820 --> 00:21:46.540 of firefighters, policemen, military personnel, Red Cross workers, medical students, doctors, 162 00:21:46.540 --> 00:21:55.840 nurses, housewives, and boy scouts. This medical student also performed mouth to mouth and mouth 163 00:21:55.840 --> 00:22:04.160 to airway breathing after one demonstration only. Here she did mouth to mouth breathing for 30 minutes 164 00:22:04.160 --> 00:22:12.340 without interruption producing tidal volumes between one and two liters each. She's using the thumb jaw lift 165 00:22:12.340 --> 00:22:19.620 method. 90 percent of our 167 untrained rescuers after one demonstration produced inflations of 166 00:22:19.620 --> 00:22:26.620 over 500 milliliters with mouth to mouth breathing during the initial 60 seconds. 94 percent with this 167 00:22:26.620 --> 00:22:38.720 method. 87 percent with a hands jaw lift method. You see in the corner the subject's relative arterial 168 00:22:38.720 --> 00:22:48.740 oxygen saturation. It is 97 percent which is room air control value. Now we will show you how rapidly 169 00:22:48.740 --> 00:22:55.800 hypoxia develops and how rapidly mouth to mouth breathing can re-oxygenate the apneic subject. 170 00:22:57.760 --> 00:23:06.860 The victim is still paralyzed. Watch the drop of the oxygen saturation in the corner. 30 seconds 171 00:23:06.860 --> 00:23:31.460 without breathing and it drops. 80. Now re-oxygenate. One, two, three, four, five, six, seven breaths and back to 95 percent. 172 00:23:32.280 --> 00:23:37.740 After about 10 deep inflations at the rapid rate the subject was re-oxygenated. 173 00:23:43.060 --> 00:23:49.480 For maintenance breathing a slower rate is adequate. Ventilation with expired air could 174 00:23:49.480 --> 00:23:56.140 maintain oxygen and carbon dioxide values normal when tidal volumes were at least twice as large 175 00:23:56.140 --> 00:24:05.360 as normal. This is in an adult one liter per breath or more. Here as few as six to ten inflations 176 00:24:05.360 --> 00:24:18.000 per minute maintain the oxygen saturation around 95 percent. Notice how her left thumb is wrapped 177 00:24:18.000 --> 00:24:23.740 with a piece of cloth. This is a precaution during prolonged mouth-to-mouth breathing when 178 00:24:23.740 --> 00:24:30.760 thumb became sore during support of the lower teeth. We are going to record the end expiratory 179 00:24:30.760 --> 00:24:36.920 carbon dioxide concentrations of the rescuer and the subject. When the subject was breathing 180 00:24:36.920 --> 00:24:44.700 spontaneously through the analyzer while conscious we obtained this control curve. During inspiration 181 00:24:44.700 --> 00:24:52.420 the carbon dioxide measured at the mouth is zero. During expiration it rapidly increases 182 00:24:52.420 --> 00:25:00.780 and levels off between five and six percent. This plateau of the curve indicates the end expiratory 183 00:25:00.780 --> 00:25:08.380 carbon dioxide which is the aldeolar carbon dioxide. Again inspiration and expiration. Now 184 00:25:08.380 --> 00:25:15.620 the analyzer is between the airway and the rescuer. The arrows indicate the moments when the rescuer 185 00:25:15.860 --> 00:25:22.820 blows. You can see a drop of the carbon dioxide concentration when the rescuers dead space air 186 00:25:22.820 --> 00:25:30.140 moves through the analyzer into the victim and the return to a first plateau which indicates the 187 00:25:30.140 --> 00:25:36.620 rescuers aldeolar carbon dioxide between three and four percent. Then during passive expiration 188 00:25:36.620 --> 00:25:43.240 of the subject the subject's aldeolar sample appears as a second plateau between four and six 189 00:25:43.240 --> 00:25:49.560 percent. As you see none of the aldeolar values of the subject are greater than the control value 190 00:25:49.560 --> 00:26:01.980 indicated by this red line. Here the rescuer takes a deep breath and blows forcefully. The air column 191 00:26:01.980 --> 00:26:09.960 moving into the victim first contains almost no carbon dioxide. Here he takes a shallow breath 192 00:26:09.960 --> 00:26:19.540 before blowing. There is no dip to zero. Here the infrared carbon dioxide analyzer is placed 193 00:26:19.540 --> 00:26:32.460 between the mouth-to-mouth airway and the rescuers mouth. The carbon dioxide tracing is in the corner. 194 00:26:32.460 --> 00:26:38.220 Observe how far to the right the pen moves with each expiration of the subject. 195 00:26:44.580 --> 00:26:52.020 Now deliberate apnea. The oximeter in the corner shows deoxygenation. The carbon dioxide tracing 196 00:26:52.020 --> 00:27:00.620 would show nothing during apnea because no air is moving. The oxygen saturation drops. Watch 197 00:27:00.620 --> 00:27:11.620 the carbon dioxide tracing when resuscitation starts. Now during the first few inflations the 198 00:27:11.620 --> 00:27:17.160 pen moved beyond the control value to the right indicating wash out of the accumulated carbon 199 00:27:17.160 --> 00:27:26.520 dioxide. Now the pen stays within control levels. The lack of the end expiratory plateau indicates 200 00:27:26.520 --> 00:27:33.140 too rapid breathing. The next inflation should not be performed unless the lungs have deflated. 201 00:27:35.480 --> 00:27:41.880 We measured the amount of air blown into the stomach. Gastric distension may occur during 202 00:27:41.880 --> 00:27:46.900 mouth-to-mouth breathing when the mandible is poorly supported or when the inflations are 203 00:27:46.900 --> 00:27:55.400 excessively forceful. Gastric distension proved harmless and preventable. Sometimes no air was 204 00:27:55.400 --> 00:28:00.500 found after 15 minutes of correct mouth-to-mouth breathing. At other times between thousand and 205 00:28:00.500 --> 00:28:06.900 nineteen hundred milliliters were measured. The air collected in the bag is measured by water 206 00:28:06.900 --> 00:28:21.200 displacement. When during resuscitation the epigastric area protrudes, pressure over the 207 00:28:21.430 --> 00:28:33.810 between breaths can expel the air. A rescuer skilled with endothracheal intubation who carries 208 00:28:33.810 --> 00:28:40.710 the proper equipment will find mouth to endothracheal tube breathing to be the most effective expired 209 00:28:40.710 --> 00:28:47.150 air method for immediate reoxygenation of an asphyxiated person. The endothracheal tube 210 00:28:47.150 --> 00:28:53.350 makes support of the mandible unnecessary. The cuff prevents air leakage and gastric 211 00:28:53.350 --> 00:28:58.750 distension does not occur. At this point the succinylcholine infusion is discontinued and 212 00:28:58.750 --> 00:29:04.630 the subject is permitted to recover. He had received a total of 3,400 milligrams of succinylcholine 213 00:29:04.630 --> 00:29:15.890 within three hours. Gradual recovery of muscle power occurs within about 30 minutes. We therefore 214 00:29:15.890 --> 00:29:22.990 conclude that the problem of upper airway obstruction in the unconscious person deserves 215 00:29:22.990 --> 00:29:29.930 more attention. Positive pressure breathing may overcome partial obstruction. When the person 216 00:29:29.930 --> 00:29:39.230 is found apneic, immediate reoxygenation is needed. One should not wait until resuscitation 217 00:29:39.230 --> 00:29:46.370 arrives. Back pressure arm lift and chest pressure arm lift methods of artificial 218 00:29:46.370 --> 00:29:57.210 respiration proved unreliable. With mouth-to-mouth breathing, reoxygenation can be accomplished 219 00:29:57.210 --> 00:30:02.890 within seconds by deep inflations through an open airway.