Brit. J. Anaesth. (1963), 35, 414
HUMAN OXYGENATION BY AIR DURING ANAESTHESIA: THE RELATION OF VENTILATORY VOLUME AND ARTERIAL OXYGEN SATURATION BY
ICHIRO WAKAI
Department of Anaesthesia, Nagoya University Hospital, Nagoya, Japan SUMMARY
The use of air as a vehicle gas for volatile anaes- a Jefferson Ventilator with Wakai T-valve, and a thetic agents during inhalation anaesthesia has Ruben valve connected to the endotracheal tube. long been considered a safe practice, particularly This open non-rebreathing system permits ventiin the case of the open drop technique with ether. lation of the lungs of the patients with air conOn the other hand, anaesthetists have long been taining a predetermined concentration of a volatile in the habit of administering oxygen-enriched gas agent. mixtures for the sole purpose of preventing In the first series of twelve patients inhaling hypoxaemia. The availability of an oxygen-rich ether and air from the EMO inhaler, the average atmosphere, however, does not guarantee the of arterial oxygen saturation levels was 91.8 per adequacy of arterial blood oxygenation or carbon cent during spontaneous respiration and 95.2 per dioxide elimination, unless the maintenance of cent during controlled respiration. It has been proper pulmonary ventilation is ensured. subsequently revealed, while measuring arterial In recent years, some anaesthetists have investi- oxygen saturation of the patients under various gated the validity of oxygenation by air during conditions of artificial respiration that there is anaesthesia, having been influenced by the intro- some correlation between arterial oxygen saturaduction of calibrated inhalers for volatile anaes- tion levels and ventilatory volumes. thetics and using self-inflating reservoirs for This paper concerns the oxygenation curves artificial ventilation. They consistently emphasize obtained by plotting the levels of arterial oxygen that provided adequate pulmonary ventilation be saturation against ventilatory volumes which are maintained it is. unnecessary to administer a higher expressed as percentages of modified Radford's concentration of oxygen than is present in ordinary standard ventilation, Nunn's alternative standard ventilation during anaesthesia, and the patients' air, except in certain circumstances. Since January 1960, more than 4,000 patients resting minute volumes. have been anaesthetized with volatile agents METHOD vaporized in room air in this Department. The apparatus consisted of a calibrated vaporizer for Eighteen adult patients (11 males) were used for ether or halothane, an Oxford Inflating Bellows or this study. These patients underwent various types 414
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Ventilation and arterial oxygen saturation have been measured in 18 patients during anaesthesia with ether or halothane carried in air. All patients were ventilated artificially with a Jefferson ventilator at a frequency of 16 breaths per minute and variable tidal volume. Ventilation has been expressed as a percentage of Radford's standard, Nunn's standard and the patient's pre-operative resting ventilation. 110 per cent of both Radford's and Nunn's standard ventilation and 98 per cent of the patient's own resting ventilation were found to yield a mean arterial oxygen saturation of 95 per cent. Below this the mean saturation fell sharply with decreasing ventilation. Cyanosis was never visible even with a saturation as low as 70 per cent, although desaturation was evident in the colour of the arterial blood when sampled.
HUMAN OXYGENATION BY AIR DURING ANAESTHESIA
the unit consisting of a calibrated vaporizer, a Wakai T-valve (Wakai, in preparation), a Jefferson Ventilator, and a Ruben valve (fig. 1). By manipulating the pressure-regulating valves and the rate adjuster, it was possible to ventilate the patient's lungs with definite tidal volumes or minute volumes of air containing the weak anaesthetic vapour. Ventilation was measured with a Drager volumeter connected to the expiratory side of the Ruben valve. The value was converted to BTPS. The Drager volumeter operates with around +7.5 per cent errors of flow rates in sinusoidal air flow (Byles, 1960). Arterial blood samples were drawn during the early period of operation after ventilation was kept constant for 5 minutes. More than two blood samples were obtained from each patient under various ventilatory minute volumes. The positive pressure induced in the airway varied from 8 to 28 cm H2O and the ventilatory rate was fixed at 16 per minute except for four occasions when marked hyperventilation was induced. Each blood sample was analyzed for oxygen content and
FIG. 1 Anaesthetic system used in this study. The Wakai T-valve and the Jefferson ventilator are placed between the EMO ether vaporizer or Fluotec vaporizer and the Ruben valve.
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of operations in the supine or lateral position, with the exception of intrathoracic procedures. They had no apparent cardiopulmonary disorders and had haemoglobin indices of more than 70 per cent Sahli. Pre-anaesthetic medication consisted of pentobarbital sodium 100 mg and atropine sulphate 0.5 mg, 2 hours and 1 hour respectively prior to the induction of anaesthesia. Anaesthesia was induced with thiamylal sodium in doses ranging from 200 to 300 mg, followed by endotracheal intubation facilitated by 40 mg suxamethonium chloride. Artificial ventilation by air containing 3 per cent ether or 1 per cent halothane was started immediately after administering suxamethonium, and the patient was kept under hyperventilation for about 1 minute. In most cases ventilatory interruption due to endotracheal intubation did not exceed 30 seconds. At the first sign of the receding effect of suxamethonium, 21 mg of d-tubocurarine chloride was injected intravenously to maintain apnoea. Intermittent positive pressure ventilation was continued, using
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BRITISH JOURNAL OF ANAESTHESIA
416
TABLE OF RESULTS
Minute volumes of intermittent positive pressure ventilation, expressed in ml and as percentages of the three ventilation standards, and the resultant arterial oxygen saturations during ether-air and halothane-air anaesthesia in 18 subjects. Arterial blood samples were drawn after ventilation was kept constant for 5 minutes.
Subject, operation performed and anaesthetic agents
Induced minute volume (ml) BTPS*
7700 4224 2618
(2) T.H., 43, F, 148 cm, 61 kg Right nephropexy, cholecystectomy (ether-air)
7480 5412
(3) H.K., 22, F, 152 cm, 45 kg Craniotomy (ether-air)
3344 2684
4900
4790
11660 5555
(5) M. H., 19, F, 154 cm, 47 kg, Craniotomy (halothane-air)
14795 8580 4290
141.5 102.5
88 70.5
270 129
361 209 105
7645 5346
(7) H.I., 35, M, 167 cm, 66 kg Left inguinal colostomy (ether-air)
7645 8800
(8) A.Y., 15, F, 158 cm, 59.5 kg Curettage, left humerus (ether-air)
6732 3872
(9) M.I., 36, F, 152 cm, 50 kg Breast amputation (ether-air)
5280 3487
5620
148.5 104
135 95
133 153
141 162
5700
5520 122 70
137.5 91
203.5 97
99.2 95.4
228 132 66
98.9 99.1 84.6
116 81
92.3 83.0
134 154
97.2 98.8
107 61.5
89.3 71.0
105.5 69
94.4 84.8
6300 118 68
3900
3840
93.5 87.5
5700
5400
5730
109 83.5
6590
5150
(6) Y.K., 23, M, 159 cm, 60 kg, Open reduction right hip joint (ether-air)
98.5 91.0
6500
4100 356 206 103
110 80
5720
4300
4160
96.8 92.5 70.5
3200
3800 83.5 67
255 122
160.5 88 54.5 6800
5300
4560
(4) K. H., 42, M, 162 cm, 50 kg Right lumbar sympathectomy (halothane-air)
157 86 53.5
133.5 99.5
4220
Arterial oxygen saturation (%)
4800
165 88.5 55 5440
Resting minute volume (ml) BTPSJ and ratio of induced ventilation (%)
5000 135 87.5
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(1) Y.M., 19, M, 158 cm, 50 kg Tendinoplasty, left hand (halothane-air)
Radford's standard minute volume (ml) BTPSf and ratio of induced ventilation (%)
Nunn's standard minute volume (ml) BTPS and ratio of induced ventilation (%)
HUMAN OXYGENATION BY AIR DURING ANAESTHESIA
417
TABLE OF RESULTS (continued)
Subject, operation performed and anaesthetic agents
(13) Y.O., 22, M, 160 cm, 54 kg Left nephrectomy (halothane-air) (14) Z.I., 25, M, 162 cm, 55 kg Gastrectomy (ether-air) (15) E.Y., 32, F, Curettage, right tibia (halothane-air) (16) K.N., 28, M, 164 cm, 53 kg, Craniotomy (halothane-air) (17) T.T., 36, F, 148 cm, 40 kg Craniotomy (halothane-air) (18) K.I., 22, M, 169 cm, 45 kg Gastroenterostomy (halothane-air)
4300
4760 118 99.5 158
5610 4752 7535
134 128 144.5 133
124 110.5 71.5
163.5 119
3600 466.5 352
8700
472 355
4700 229 94.5
5600
256 107
117 180.5 228 4640 256 167.5 91 88.5
11880 7755 4235 4125 4920 8030 5852 3570 16830 12650 4170 10780 4466
112 107
98.8 97.5
110 101
96.6 95.8
104.5 93.5 60.5
98.0 96.0 75.2
123 191.5 242
98.0 98.1 99.3
229 147 81.5 79
98.0 97.5 89.0 87.5
114 83.5
96.8 86.5
194 145
97.8 98.4
185 80
96.8 92.6
5200
122 109 70.5 5000 123 191.5 242 5000 237.5 155 84.5 82.5 4900 164 119
5300 6182 9570 12100
95.5 92.5 99.0
7400 170.5 157
4450
4390 5445 4862 3146
110 93.5 146 5400
132 125.5 4750
5620 8140 7480
Arterial oxygen saturation (%)
5100
130 111 175 4600
4480 6050 5742
Resting minute volume (ml) BTPSt and ratio of induced ventilation (%)
5000
5200
7000
* Induced minute volume measured by the method shown in figure 1 was converted into BTPS. t Radford's standard minute volume was converted into BTPS multiplying by 1.080. This figure was then reduced by 960 ml assuming the average upper airway deadspace eliminated by intubation in this study to be 60 ml. J Resting minute volume was measured by applying volumeter directly to mouth-piece, which partly eliminated upper airway dead space. Though the volumeter was heated by the expired air, the figures are still slightly smaller than BTPS.
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(10) M.N., 20, M, 162 cm, 45.5 kg, Right nephrectomy (halothane-air) (11) O.M., 25, M, 164 cm, 48.5 kg Craniotomy (ether-air) (12) Y.A., 52, M, 163 cm, 59 kg Radical resection left maxilla (ether-air)
Induced minute volume (ml) BTPS*
Nunn's standard Radford's minute standard volume (ml) minute BTPS volume (ml) and ratio of BTPSf and induced ratio of induced ventilation ventilation (%) (%)
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BRITISH JOURNAL OF ANAESTHESIA
saturation by Van Slyke's manometric method as modified by Goldstein, Gibbon, Allbritten and Stayman (1950). The oxygen saturation levels were plotted against the ventilatory volumes expressed as percentages of the three ventilation standards.
RESULTS
The induced minute volumes of artificial ventilation in each subject expressed as percentages of the three ventilation standards, together with the resultant arterial oxygenation levels are set out in the table. There were nine patients in whom anaesthesia was maintained by the constant inhalation of 1 per cent halothane in air. The hypotension associated with the combined use of d-tubocurarine and halothane, to which attention has been drawn by previous investigations (Johnstone, 1956; BryceSmith and O'Brien, 1956; Marrett, 1957; Hansen, Davies and Hardy, 1959), was less significant, even under positive pressure ventilation, when d-tubocurarine was injected slowly in diluted solution than in patients in whom anaesthesia was maintained by
100 — c
o 90--
70--
60
Ether Halothane
-I—1—450
-I—I—I-
-I
1 1—I
1 1 1 1-
210 230 130 150 170 190 Yo of Standard Ventilation FIG. 2 The relation of arterial oxygen saturation and ventilatory minute volume expressed as a percentage of Radford's standard 70
90
110
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Ventilation standards. A suitable indication of ventilation was required to express the various ventilatory minute volumes in the individual subject which produce certain arterial oxygenation levels. The Radford nomogram (Radford, Ferris and Kriete, 1954; Radford, 1955) has been suggested for use during anaesthesia (Scurr, 1956; Nunn, 1960a). In order to standardize the conditions of ventilatory measurement in this study, the figures obtained from the Radford nomogram were converted to BTPS and then reduced by 960 ml assuming the average upper airway deadspace eliminated by endotracheal intubation to be 60 ml. Nunn (1960b) has suggested an alternative method of predicting arterial carbon dioxide tension during anaesthesia from the ventilation. The present author adopted this method for standardizing the minute volume of artificial
ventilation in order to maintain the arterial carbon dioxide tension at 40 mm Hg during anaesthesia, which has been suggested as a suitable index for the maintenance of ventilation by Woolmer (1960). As another ventilation standard, the patients' resting minute volumes were used.
uuimm HUMAN OXYGENATION BY AIR DURING ANAESTHESIA
419
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the constant inhalation of 3 per cent ether in air resting minute volume causes 77 per cent desaturawhile d-tubocurarine was injected in non-diluted tion of oxygen. form (Oda et al., 1961). There was no significant difference in blood oxyThe arterial oxygen saturation levels plotted genation between the groups anaesthetized with 3 against Radford's ventilation standard (fig. 2) per cent ether and 1 per cent halothane. formed a hyperbolic distribution, although with a In all the subjects studied, cyanosis was under wide range of distribution, which resembled the no circumstances observed. This was true even oxygen dissociation curve of haemoglobin. The during hypoventilation sufficient to cause an arterdotted line is a smooth curve closely approximat- ial oxygen saturation of 70.5 per cent in a 19ing to the mean figures obtained from all saturation year-old male (Subject 1), although the colour of and ventilation values lying within each 20 per the blood had become warningly dark at the time cent interval on the abscissa. On this curve arterial of sampling. oxygen saturation of 95 per cent or more is likely to be produced by ventilation of more than 110 DISCUSSION per cent of the standard, but arterial oxygen saturation drops steeply as ventilation decreases below The potential dangers of using air as the only 110 per cent of the standard. means of blood oxygenation during inhalation The arterial oxygen saturation levels plotted anaesthesia have been suggested by many authors. against Nunn's alternative ventilation standard Weitzner, King and Ikezono (1959) studied the during anaesthesia show an almost similar distri- rate of arterial oxygen desaturation during apnoea bution to that noted when these were plotted after hyperventilation with air and with 100 per against the modified Radford's ventilation standard, cent oxygen. In the former circumstances arterial and also with a wide range of variation (fig. 3). On oxygen saturations dropped to dangerous levels the estimated ventilation-oxygenation curve on within 11 minutes, while in the latter oxygen Nunn's standard, it appears that 110 per cent ven- saturation was well maintained during the first 2 tilation is likely to be necessary for 95 per cent minutes. They admitted that the use of 100 per saturation of arterial blood. It is also shown that cent oxygen prior to apnoea would have an advanoxygen saturation drops steeply as ventilation tage over ordinary air in maintaining oxygen saturadecreases below 110 per cent of Nunn's standard. tion longer at an acceptable level. The polaroFigure 4 shows the distribution of arterial oxy- graphic study of the same problem by Heller and gen saturations plotted on the standard of the Watson (1961) also suggested that it is advantagpatients' resting minute volumes. The arterial oxy- eous to use 100 per cent oxygen instead of 21 per gen saturations formed a hyperbolic curve with a cent oxygen (room air) prior to induced apnoea. surprisingly narrow range of distribution compared Fujimori and Virtue (1960), in their electroencewith the former two plottings. On the estimated phalographic study, also stressed the greater safety ventilation-oxygenation curve, arterial oxygen obtained by the use of 100 per cent oxygen for saturation of 95 per cent or more is likely to be ventilating the subject's lungs before intubation secured by the ventilation of more than 98 per cent using the apnoeic technique. of the patients' resting minute volumes, and arterThe results of these investigators manifestly ial oxygen saturation also drops steeply as ventila- demonstrated more rapid desaturation after breathtion decreases below 98 per cent of the resting ing air than after breathing oxygen-enriched mixminute volume. tures prior to the onset of apnoea. The fact has Observation of each ventilation-oxygenation often been emphasized that the body cannot store curve reveals that ventilation of more than 110 a significant amount of oxygen. The question per cent of the standard increases the arterial arises: "What would be an adequate ventilation oxygen saturation only to the extent of 5 per cent, to maintain the normal levels of arterial oxygen while 70 per cent ventilation of Radford's standard saturation, using gas mixtures of different oxygen causes desaturation of around 70 per cent, 70 per concentration or tension?" The possibility of air cent of Nunn's standard causes 74 per cent being inadequate for man's breathing, in relation desaturation, and 70 per cent of the patient's to its density or altitude, has long been known.
BRITISH JOURNAL OF ANAESTHESIA
420
o
<
70- -
Ether Halothane
60 50
70
90
110
130 150 170 190 230 210 °/0 of Standard Ventilation FIG. 3 The relation of arterial oxygen saturation and ventilatory minute volume expressed as a percentage of Nunn's standard
I ."• to
70--
o •
60 . 50
I
Ether Halothane
I I I I I I I I I I I I
230 210 130 150 170 190 °/0 of Standard Ventilation FIG. 4 The relation of arterial oxygen saturation and ventilatory minute volume expressed as a percentage of resting minute velume. 70
90
110
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.2
HUMAN OXYGENATION BY AIR DURING ANAESTHESIA
produced satisfactory blood oxygen levels during controlled ventilation with ether-air mixtures. They also noted saturation levels of more than 95 per cent during spontaneous respiration but observed that the lowest saturation occurred during manually assisted respiration. This was probably due to unsteady or irregular ventilatory volumes. Nandrup (1959) reported on the use of ether-air mixture with controlled ventilation. He found arterial oxygen levels to be above or equal to normal on all occasions. Poppelbaum (1960) described oximetry during ether-air and halothane-air anaesdiesia for thoracic operations. His continuous measurement showed adequate oxygenation in the great majority of cases. Papantony and Landmesser (1960) reported on their own anaesthetic device for halothane-air anaesthesia. In their series the average of arterial oxygen saturations in the group in which ventilation was controlled was 94.3 per cent but only 90.7 per cent in the group in whom respiration was spontaneous. A similar unit for halothane-air anaesthesia was described by Macartney (1961), and in 102 consecutive cases the arterial blood appeared satisfactorily pink as long as ventilation was maintained in accordance with Radford's nomogram. More precisely, Cole and Parkhouse (1961) showed in sixty-two cases in which ventilation was controlled using volatile agents in air, that oxygenation levels within 2 per cent of resting levels were maintained in 92 per cent. Merrifield (1961) reported ventilatory measurements in eighteen subjects breathing spontaneously the halothane-ether azeotrope in air, with concomitant measurement of arterial oxygen saturations. The mean saturation was 95.4 per cent at a mean ventilation of 97.4 per cent of predicted ventilations. He suggested that the changes in saturation levels did not always correspond with changes in ventilation but that a fairly close relationship would be found between the two. The results of the present study show that there is a good relationship between ventilatory volume and arterial oxygen saturation during artificial ventilation of the anaesthetized patient with air. Although the patients from whom blood samples were drawn were in light planes of anaesthesia, and the oxygen concentration in air had been reduced by ether and halothane vapour by 0.63 per cent and 0.2 per cent respectively, the relation between ventilatory volume and oxygenation levels was
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Human respiratory and circulatory responses in themselves work to combat the hypoxic condition due to exposure to low tension of oxygen, and in normal man inhalation of 10 per cent oxygen at sea level (76 mm Hg, equivalent in tension to the altitude of 5180 m) provokes marked respiratory stimulation leading to increased minute volume. The circulatory response appears as the progressive increase of the pulse rate and cardiac output with decrease of oxygen tension below normal. These physiological responses, however, fail to maintain the normal arterial oxygen saturations, and the inhalation of 18 per cent oxygen results in 94 per cent saturation and of 16 per cent oxygen results in 91 per cent saturation (Dripps and Comroe, 1947). Having a relatively high affinity for oxygen, the physical nature of haemoglobin affords an oxyhaemoglobin saturation of approximately 84 per cent at an altitude of 4,000 m (Lowry, 1961). To a certain extent the oxygen saturation may be increased under anoxic conditions by hyperventilation (Houston, 1946). The question of ventilation by air during anaesthesia should be discussed with these limitations in mind. Faulconer and Lattrell (1949) reported saturations as low as 70 per cent during ether-air anaesthesia, while they noted an oxygen tension of 128 mm Hg in the air under the mask before adding ether, instead of 152 mm Hg at the altitude of 305 m. This oxygen tension under the mask is equivalent to 16.8 per cent oxygen at sea level. Here arises the problem of suitable breathing systems when using air as the principal diluent of volatile agents. Modern efficient automatic non-rebreathing valves widi minimal deadspace are available and the author would like to stress the value of a non-rebreathing system while using air, because it enables pulmonary ventilation to be accurately measured. Artificial ventilation by air during anaesthesia has been shown to maintain adequate arterial oxygen saturations. Campbell, Nunn and Peckett (1958) obtained average arterial oxygen saturations of 96.3 per cent and 95 per cent in their six subjects under spontaneous and artificial respiration respectively, when room air was the only inspired gas during thiopentone anaesthesia. Parkhouse and Simpson (1959) in their "Restatement of Anaesthetic Principles" suggested that air as a vehicle for anaesthetic vapours is ideal and should be used extensively. Dcezono, Harmel and King (1959)
421
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BRITISH JOURNAL OF ANAESTHESIA
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similar to that in the subject ventilated with room too severely impaired ventilation. The addition of air. oxygen in the inhaled air will shift the curve to the On the three ventilation-oxygenation curves here left and the reduction of oxygen from the air will obtained, the somewhat wide range in the distri- shift the curve to the right, as does the change in bution of arterial oxygen saturations may be attri- pH on the oxygen dissociation curve of haemobuted to many factors such as variations in alveo- globin. This assumption suggests that the availlar ventilation due to altered physiological dead- ability of additional oxygen to the inhaled air should space or altered distribution of pulmonary circula- also be supported by an adequate volume of ventilation which could be caused by the change in tion in any event. The reduction in oxygen tension airway pressure, or may be attributable to varia- resulting from adding the vapour of any volatile tions in metabolic rate. There might also have agent, at present available for the maintenance of been examples of lowered arterial oxygen levels in light levels of anaesthesia, is by no means so great pre-operative resting patients as described by Lam- in extent that ventilation fails to keep oxygen bertsen et al. (1952) and Cole and Parkhouse saturations at the normal level, unless circulatory (1961). In normal individuals breathing the same derangement is caused by anaesthetics or surgical oxygen concentration a wide range in arterial manoeuvres. oxygen levels occurs, as repeatedly shown by The versatility of the EMO ether Inhaler previous reporters (Barach et al., 1941; Pruitt, (Epstein and Macintosh, 1956) and its physical Burchell and Barnes, 1945; Houston, 1946; Dripps principles have led to many reports of experiences and Comroe, 1947). or recommendations about the use of similar units The least random variation of oxygen saturations vaporizing volatile agents in air in a non-rebreathis on the ventilation-oxygenation curve based on ing system (Parkhouse and Simpson, 1959; Ikezono the patient's resting respiration, which suggests et al., 1959; Soper, 1959, 1961; Papantony and that the resting minute volume of individuals is Landmesser, 1960; Hingson, 1961; Cole and Parkthe best guide for artificial ventilation with air. house, 1961; Macartney, 1961; Merrifield, 1961; The wide difference between the resting minute Safar and Gedang, 1961; Pearson and Safar, 1961). volumes and the standard ventilations calculated The limitation in the oxygen tensions in the infrom Radford's nomogram is probably due to the haled air when using these techniques raises quesindividual variation in metabolic rate, diffusion tions concerning the degree of ventilation required capacity of the pulmonary membrane, and other to maintain arterial oxygen saturations at normal factors which do not apply to the physiological levels. The ventilation-oxygenation curves obtained nomogram based on the basal carbon dioxide pro- in this study may be of value as a guide to ventiladuction and respiratory deadspace estimated from tion. body weight. The same can be said of Nunn's alternative method of prediction of ventilation during anaesthesia according to carbon dioxide homeoACKNOWLEDGMENTS stasis. These two ventilation standards are invalu- For their continuous encouragement, my thanks are able when it is necessary to institute artificial due to the Nuffield Department of Anaesthetics, and respiration in the apnoeic or anaesthetized patient in particular to Prof. Sir Robert Macintosh, the stimulus of whose visit to Japan cannot be overestiwhose basal minute volume is not known, but as mated. I am indebted to Prof. Y. Hashimoto who gave long as information is available about the patient's me the opportunity to carry out this work. My thanks resting minute volume prior to anaesthesia, it is are also due to my colleagues for facilitating and assisting in the preparation of this paper. the most suitable guide for blood oxygenation. The resemblance of the ventilation-oxygenation curve using a gas of fixed oxygen concentration to REFERENCES the oxygen dissociation curve of haemoglobin is of interest. It is suspected that the complete form of Barach, A. L., Steiner, A., Eckman, E., and Molomut, N. (1941). Physiologic action of oxygen and carbon the ventilation-oxygenation curve will be an Sdioxide on coronary circulation, as shown by shaped hyperbola, though not perfected in this blood gas and electrocardiographic studies. Amer. study to avoid the risk of exposing the subjects to Heart ]., 22, 13.
HUMAN OXYGENATION BY AIR DURING ANAESTHESIA Bryce-Smith, R., and O'Brien, H. D. (1956). Fluothane: a non-explosive volatile agent. Brit. med. J., 2, 969. Byles, P. H. (I960). Observations on some continuously-acting spirometers. Brit. J. Anaesth., 32, 470. Campbell, E. J. M., Nunn, J. F., and Peckett, B. W. (1958). A comparison of artificial ventilation and spontaneous respiration with particular reference to ventilation bloodftow relationships. Brit. J. Anaesth., 30, 166. Cole, P. V., and Parkhouse, J. (1961). Blood oxygen saturation during anaesthesia with volatile agents vaporized in room air. Brit. J. Anaesth., 33, 265.
Epstein, H. G., and Macintosh, R. R. (1956). An anaesthetic inhaler with automatic thermo-compensation. Anaesthesia, 11, 83. Faulconer, A. jr., and Lattrell, K. E. (1949). Tension of oxygen and ether vapor during use of semiopen air-ether method of anesthesia. Anesthesiology, 10, 247. Fujimori, M., and Virtue, R. W. (1960). The value of oxygenation prior to induced apnoea. Anesthesiology, 21, 46. Goldstein, F., Gibbon, J. H. jr., Allbritten, F. K. jr., and Stayman, J. W. jr. (1950). The combined rnanometric determination of oxygen and carbon dioxide in blood, in the presence of low concentrations of ethyl ether. /. biol. Chem., 182, 815. Hansen, J. M., Davies, J. I., and Hardy, M. H. (1959). Fluothane: clinical appraisal and report of its use in 1,000 cases. /. Kans. med. Soc, 60, 126. Heller, M. L., and Watson, T. R. jr. (1961). Polarographic study of arterial oxygenation during apnea in man. New. Eng. J. Med., 264, 326. Hingson, R. A. (1961). World anesthesia. Anesth. Analg. Curr. Res., 40, 316. Houston, C. S. (1946). Effect of pulmonary ventilation on anoxemia. Amer. J. Physiol., 146, 613. Ikezono, E., Harmel, M. H., and King, B. D. (1959). Pulmonary ventilation and arterial oxygen saturation during ether-air anesthesia. Anesthesiology, 20, 579. Johnstone, M. (1956). The human cardiovascular response to Fluothane anaesthesia. Brit. J. Anaesth., 28, 392. Lambertsen, C J., Bunce, P. L., Drabkin, D. L., and Schmidt, C. F. (1952). Relationship of oxygen tension to haemoglobin oxygen saturation in the arterial blood of normal men. /. appl. Physiol., 4, 873. Lowry, R. H. (1961). Manned space exploration and the possibility of hypoxia. Canad. Anaesth. Soc. ]., 8, 70.
Macartney, H. (1961). Halothane-air anaesthesia using the "Pulmotec" apparatus: preliminary report. Canad. Anaesth. Soc. J., 8, 281. Marrett, H. R. (1957). Halothane: its use in closed circuit. Brit. med. J., 2, 331. Merrifield, A. J. (1961). The use of air in anaesthesia: ventilation measurements during anaesthesia with air and halothane-ether azeotrope. Brit. J. Anaesth., 33, 289. Nandrup, E. (1959). Diethyl-ether analgesia in major surgery. Ada anaesth. Scand., Suppl. II, 105. Nunn, J. F. (1960a). Ventilation nomograms during anaesthesia. Anaesthesia, 15, 65. (1960b). Prediction of carbon dioxide tension during anaesthesia. Anaesthesia, 15, 123. Oda, M., Wakai, I., Takumi, Y., and Yamashita, H. (1961). Combination of dTc and Fluothane-air anaesthesia. Jap. J. Anesth., 10, 556. Papantony, M., and Landmesser, C. M. (1960). Portable unit for Fluothane-air anesthesia ("PUFFA"). Anesthesiology, 21, 768. Parkhouse, J., and Simpson, B. R. (1959). A restatement of anaesthetic principles. Brit. J. Anaesth., 31, 464. Pearson, J. W., and Safar, P. (1961). General anesthesia with minimal equipment. Anesth. Analg. Curr. Res., 40, 664. Poppelbaum, H. F. (1960). Rediscovery of air for anaesthesia in thoracic surgery. Proc. roy. Soc. Med., 53, 289. Pruitt, R. D., Burchell, H. B., and Barnes, A. R. (1945). Anoxia test in diagnosis of coronary insufficiency: study of 289 cases. /. Amer. med. Ass., 128, 839. Radford, E. P. jr. (1955). yentilation standards for use in artificial respiration. J. appl. Physiol., 7, 451. Ferris, B. G. jr., and Kriete, B. C. (1954). Clinical use of a nomogram to estimate proper ventilation during artificial respiration. New Eng. J. Med., 251, 877. Safar, P., and Gedang, I. (1961). Inexpensive system for administration of ether. A nesthesiology, 22, 323. Scurr, C. F. (1956). Controlled respiration and standardization of ventilation. Brit. J. Anaesth., 28, 23. Soper, R. L. (1959). Anaesthesia for major disasters. Proc. roy. Soc. Med., 52, 239. (1961). Portable anaesthetic apparatus with vaporizer of new design. Brit. med. J., 2, 703. Weitzner, S. W., King, B. D., and Ikezono, E. (1959). The rate of arterial oxygen desaturation during apnea in humans. Anesthesiology, 20, 624. Woolmer, R. (1960). Ventilation during anaesthesia. Anaesthesia, 15, 66.
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Dripps, R. D., and Comroe, J. H. jr. (1947). The effect of the inhalation of high and low oxygen concentrations on respiration, pulse rate, ballistocardiogram and arterial oxygen saturation (oximeter) of normal individuals. Amer. J. Physiol., 149, 277.
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BRITISH JOURNAL OF ANAESTHESIA
VENTILATION D'OXYGfeNE PAR LAIR PENDANT L'ANESTHESIE: RAPPORT ENTRE VOLUME DE VENTILATION ET SATURATION ARTERIELLE EN OXYGENE
DIE SAUERSTOFFVERSORGUNG DES MENSCHEN WAHREND DER NARKOSE DURCH LUFT: DAS VERHALTNIS ATEMVOLUMEN ZU ARTERIELLER SAUERSTOFFSATTIGUNG
SOMMAIRE ZUSAMMENFASSUNG
Atmung und arterielle Sauerstoffsattigung wurden bei 18 Patienten wahrend der Narkose gemessen, die mit einem Ather- oder Halothan-Luftgemisch durchgefiihrt wurde. Alle Patienten wurden kiinstlich mit dem Gerat nach Jefferson beatmet mit einer Frequenz von 16/min. und veranderlicher Atemtiefe. Die Atmung wurde in Prozenten der Radford-Standard-Atmung, der Nunn-Standard-Atmung und der Praeoperativen Ruhe-Atmung ausgedruckt. 110% der Radford- u. der Nunn- Standard-Atmung und 98% der Ruhe-Atmung des Patienten gewahrleisteten eine mittlere arterielle Sauerstoffsattigung von 95%. Darunter fiel die mittlere Sa'ttigung bei sinkender Atemtiefe steil ab. Zyanose konnte auch bei einer Sattigung von weniger als 70% nicht beobachtet werden, obwohl eine Untersattigung durch die Farbe des entnommenen arteriellen Blutes nachweisbar war.
NOTICE The reader's attention is drawn to the fact that the articles: "Continuous cerebrospinal fluid drainage by indwelling spinal catheter" by G. Vourc'h {Brit. J. Anaesth., 35, 118) and "Problems raised by anaesthesia for thalamic and cortical exploration in neurosurgery" by G. Vourc'h, J. Hardy and M. Denavit (Brit. J. Anaesth., 35, 208) were based upon two papers read at the meeting of the Section of Anaesthetics of the Royal Society of Medicine April 6, 1962.
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L'auteur mesura la ventilation et la saturation arterielle d'oxygene chez 18 patients au cours d'anesthe'sies a Tether ou au halotbane sur "substrat-porteur" d'air. Tous ses patients furent ventile's artificiellement par un ventilateur Jefferson marchant a la frequence de seize inspirations par minute et avec un volume d'air d'amplitude variable. La ventilation est exprimee dans la pre'sente etude comme pourcentage du standard de Radford, du standard de Nunn et de la respiration pre'ope'ratoire du patient au repos. L'auteur constata que 110% des ventilations-standard de Radford et de Nunn et 98% de la ventilation normale propre du patient au repos donnerent une saturation arterielle moyenne en oxygene de 95%. En dessous de ces chiffres la saturation moyenne s'abaissa assez brutalement a mesure de la reduction de la ventilation. Aucune cyanose ne devint visible, mSme avec une saturation aussi basse que 70% — alors que l'e'tat de "desaturation" e"tait rendu Evident par la couleur des echantillons de sang arteriel.