anesth analg 1990 valentine 516 9

7/28/2019 Anesth Analg 1990 Valentine 516 9

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ANESTH ANALG1990:71:516-9516

Preoxygenation in the Elderly: A Comparisonof the Four-Maximal-Breath and Three-Minute TechniquesStephenJ . Valentine, FFARCS, obert Marjot, FFARCS,nd Christopher R. Monk, FFARCS

VALENTINE SJ,MARJOT R, MONK CR. Preoxygenationin the elderly: a comparison of the four-maximal-breathand three-minute techniques. Anesth Analg 1990;71:51&9.To compare the effectiveness of two routinely used methodsof preoxygenation in protecting against hypoxia in theelderly, the arterial 0,saturation was measured using anoximeter. Twenty-four elderly patients (265 yr) presentingfor elective orthopedic surgery were randomy allocated toreceive either 3-min or four-maximal-breaths of 100% 0,via a Bain circuit. After preoxygenation, anesthesia wasinduced, tracheal intubation performed with patients keptapneic, and the endotracheal tube 1tft open to air. The arterial

0,saturation was measured before preoxygenation and con-tinually recorded during desaturation. Although attainingsimlar arterial 0, saturation values after preoxygenation,patients in the four-maximal-breath group had significantlyshorter times ( P


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PREOXYGENATI ON N THE ELDERLY ANESTH ANAL G 5171990;71:51&9

Table1.Demographic Data and Timesto ApneaAge Height Weight Sex Hb Time toGroup (Y) (m) (kg) (M /F) (g/dL ) apnea (s)

4 V CJ 74.6 2 6.0 1.71 k 0.09 63.4 k 8.8 913 14.4 2 1.2 40.4 2 5.03 rnin 79.22 5.9 1.65 k 0.07 62.8 k 8.1 913 14.32 1.3 39.2 2 9.5(n= 12) (7G92) (1.551.78) (53-74) (1 1.8-16.7) (20-50)

(n= 12) (62-73) (1.57-1.88) (51-74) (12.6-16.8) (3045)

Hb, hemoglobin.Values are mean 2 SD, with range given in parentheses.Patients receiving the four-vital-capacity-breath method of preoxygenation.Patients receiving the 3-min method of preoxygenation

2

I-UzPav,5

Figure 1. Times to decrease in saturation frompeak Sao, to lowest Sao, levels. 0 , four-maximal-breath group; X, 3-min group.CI*x296a-e

10099989796959493929190898a

rebreathing. Patients in the 3-min group were asked

.X

I0 1 2 3 4 5 01 I I I I I 1 +l a

PEAK SaO, TIME(minuter)

3~continue t o breathe normally after application of theface mask while preoxygenation was performed for 3min. Patients in the four-breath group were asked toexhale maximally, an effective seal being obtained withthe face mask, and then requested to take four maximalbreaths. They were then told to breathe normally.Immediately after completing the preoxygenationmaneuvers anesthesia was induced with thiopental

( 24 mg/kg) and succinylcholine (1.5 mg/kg). Thepatients were not ventilated until the end of thestudy. With the onset of anesthesia and muscleparalysis cricoid pressure was applied, and the pa-tients trachea intubated under direct vision. Aftersuccessful intubation was visually confirmed the en-dotracheal tube was left open to air. If visual confir-mation was not possible the patient was excludedfrom the trial, the airway secured, and the lungsventilated with 100% 0,. Supplemental doses ofthiopental (1mg/kg) and succinylcholine(0.5mg/kg)were given every 2 min to maintain anesthesia andmuscle paralysis. A continuous recording of the arte-

rial 0, saturation (Sao,) was made and the heart rateand blood pressure recorded at 1-min intervals. Thestudy was completed when the Sao, had decreased to90%, the lungs then being ventilated with 100%O2until the Sao, was greater than 97%.The demographic data were compared by analysisof variance. Arterial 0, saturation while breathingair, the peak Sao, obtained after preoxygenation, andmean times to the onset of apnea and each desatura-tion point were compared using the Mann-WhitneyU test. P values of less than 0.05 were considered tobe statistically significant.

ResultsThe demographic data for the two groups are shownin Table1.There is no significant difference in age,height, weight, hemoglobin concentration, or time toapnea after induction of anesthesia. The number ofmen and women was similar in each group, with asimilar distribution of smokers and nonsmokers. No


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518 ANESTH ANALG1990;71:5169 VALENTINE ET AL .

Table 2. OxygenSaturationLevesBeforeand A fter Preoxygenation and Timesto Arterial DesaturationPeak Sao, T ime to97% T ime to 95% Time to 93% Timeto 90%Group Sao, on air on 100%0, Sao, Sao, Sao, Sao,

4VC" 95.4 2 1.7 99.8 2 0.5 147.52 82.4 177.1 2 90.7 193.7 2 92.1 212.1 2 91.8(n =12) (93-97) (99-100) (30-260)" (50-310)c (70-315)c (80-320)"3 minb 95.2 t 2.2 99.5 2 0.8 296.7 f 72.5 315.3 5 69.5 382.9 t 74.2 405.82 75.4(n = 12) (92-98) (98-100) (220450) (265-500) (275-530) (290-550)

Sao,, arterial oxygen saturation.Values are mean 5 SD, with the range given in parentheses.Time isgiven in seconds."Patients receiving the four-vital-capacity-breath method of preoxygenation.'Patients receiving the 3-min method of preoxygenation.' P


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PREOXYGENATION IN THE ELDERLY ANESTH ANAL G 5191990;71:51&9

rehearsals of the procedure preoperatively (once inthe ward and once in the anesthetic room), and allcooperated to the best of their ability. This rehearsaland cooperation might not be possible with somegeriatric patients.We found in our elderly patients similar Sao,values before and after preoxygenation with thesetwo techniques. However, there was a significantlyshorter time to all levels of desaturation associatedwith the four-maximal-breath method. Four patientsin this group desaturated to90%in2 min or less. Theshortest time to 90% saturation in the 3-min groupwas 4 min 50 s. This difference between our twogroups is presumably due to physiologic changes inthe respiratory system of the elderly. The agingprocess is associated with parenchymal changes ofthe diffuse emphysematous type within the lungs,changes that decrease the alveolar surface area (6,7).

The reduced total elastic recoil of the lungs impairsthe function of the distal airways with airway closureoccurring at the higher lung volumes (8). This en-croachment of the closing volume into the tidalvolume creates ventilation-perfusion mismatch. Therespiratory muscles (diaphragm and intercostal andaccessory muscles) act on a less compliant chest walland are themselves weaker, with decreased strengthand speed of contraction (9-11). The vital capacityand inspiratory and expiratory reserve volumes areall diminished. These effects combine to reduce thepulmonary reserve of the elderly in general andappear in particular to render the four-maximal-breath technique less effective in denitrogenating thefunctional residual capacity.In summary, we found that in this study of electivegeriatric patients the four-maximal-breath technique

gives similar peak Sao, values to the 3-min techniqueafter preoxygenation. However, it does not givereliable protection against desaturation during apnea.We therefore suggest that if preoxygenation is to beperformed in the elderly, the 3-min technique shouldbe used.

References1. Drummond GB, Park GR. Arterial oxygen saturation beforeintubation of the trachea: an assessment of oxygenation tech-niques. Br J A naesth 1984;56:987-92.2. Gold MI, Muraavchick S. Arterial oxygenation in consciouspatients after 3 minutes and after 30 seconds of oxygenbreathing. A nesth A nalg 1981;60:313-5.3. Gambee AM, Hertzka RE, Fisher DM . Preoxygenation tech-niques: comparison of three-minutes and four-breaths. A nesthAnalg 1987;66:46&70.4. Berthoud M, Read DH, Norman J . Preoxygenation-howlong? A naesthesia 1983;38:9&102.5. Norris MC, Dewan MD. Preoxygenation for cesarian section: acomparison of two techniques. A naesthesiology 1985;62:827-9.6. Azcuy A, Anderson A E J r, Foraker AG. The morphologicalspectrum of aging and emphysematous lungs. Ann InternMed 1962;571-17.7. Pump K K . The aged lung. Chest 1971;60:571-7.8. Stephen CR, A ssaf RAE. Geriatric anaesthesia: principles andpractice. L ondon: Butterworth, 1986:69.9. Mittman C, Edelman NH, Norris AH. Relationship betweenchest wall and pulmonary compliance and age. J A ppl Physiol1965;20:1211-6.

10. Robinson S. Physical fitness in relation to age. In: Cander L,Moyer J H , eds. Ageing of the lung: perspectives. New Y ork:Grune& Stratton, 1964:287-301.11. Du Bois AB, A laela R. Airway resistance and mechanics ofbreathing in normal subjects 75 to 90 years of age. In: CanderL, Moyer J H, eds. Ageing of the lung: perspectives. New York:Grune & Stratton, 1964:156-62.

anesth analg 1990 valentine 516 9

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