Preoxygenation in the Elderly: Comparison of 3-min and Four Deep Breath Techniques

INTRODUCTION: Preoxygenation with 100% O2 before anesthesia induction is a standard procedure in anesthesia practice. With preoxygenation, alveolar washout of air mixture in functional residual volume provides higher alveolar oxygen concentration up to 100% which leads to increased alveolar oxygen reserve, so during apnea, time to desaturation levels is delayed. We studied two different preoxgenation methods in elderly patients and compared four deep breath and 3-min techniques to decide which one is more efficient in this patient group.
METHODS: A total of 30 patients over 60 years were included in the study. Electrocardiography, systolic artery pressure (SAP), heart rate (HR), and SpO2 were monitored. Data were recorded before preoxygenation, after anesthesia induction, after intubation, and when SpO2 reached to 93%. Blood gas analysis was also performed at the same time points. Time to reach to SpO2 levels of 97%, 95%, and 93% was also recorded. Group I (n=15) patients were asked to breath normally for 3 min after the mask was tightly applied to the patients’ face. In Group II (n=15), the patients were asked to take four deep breaths when ordered by the anesthetist and then breath normally. Anesthesia induction was performed after the completion of preoxygenation. Following the induction of anesthesia and complete muscular paralysis, entubation of the trachea was performed. The distal end of the tube was left open, the patients were not ventilated until SpO2 levels reached to 93%, and, then they were ventilated with 100% oxygen and the study ended.
Data were recorded before preoxygenation, after anesthesia induction, after intubation, and when SpO2 reached to 93%. Blood gas analysis was also performed at the same time points. Time to reach to SpO2 levels of 97%, 95%, and 93% were also recorded.
RESULTS: The study was completed with 29 patients. There were no difference in demographic variables, Hg levels and time to apnea (p>0.05). Median age of the patients was 65, 8 years (61–76) in Group I and 65. 2 years (60–74) in Group II. The HR were different in two groups at the time points of SpO2 97%, 95%, and 93%, and time to reach these desaturation points was significantly different in four deep breath group of patients (p<0.001, p<0.01, and p<0.05).
DISCUSSION AND CONCLUSION: The physiological changes affect lung capacities and reserves in elderly patients. We conclude that, as the effectiveness of vital capacity breaths was decreased in these patients, 3 min of tidal breaths should be the method of choice for preoxygenation in this patient group.

Yaþlý Hastalarda Preoksijenizasyon: Üç Dakika ve Dört Derin Nefes Tekniklerinin Karþýlaþtýrýlmasý

GÝRÝÞ ve AMAÇ: Genel anestezide indüksiyon öncesi %100 O2 ile preoksijenizasyon, standard bir uygulamadýr. Preoksijenasyon lie fonksiyonel residüel kapasite(FRC) içerisindeki, nitrojen ve su buharýnýn da bulunduðu hava karýþýmýný yýkanýr.Böylece akciðerlerdeki oksijen reservi arttýrýlýr ve apnenin baþlamasýndan sonra hipoksi oluþumuna kadar geçen süre artar.
Çalýþmamýzda anestezi pratiðinde giderek daha fazla sayýda karþýlaþýlan geriatrik hasta grubunda bu iki metodu, 3 dk süre ile tidal solunum ve 4 derin nefes tekniklerini karþýlaþtýrdýk

YÖNTEM ve GEREÇLER: Çalýþmaya 60 yaþ üzeri 30 hasta alýndý. Tansiyon arteriyel, kalp hýzý, SpO2, EKG monitorize edildi. Ölçümler preoksijenasyon öncesi, anestezi indüksiyonu sonrasý, entübasyon sonrasý,ve SpO2 %93 düzeyinde alýndý, saturasyonlarýn %97,95 ve 93 e düþme süreleri kaydedildi.Belirtilen zamanlarda ayrýca kan gazý alýndý.
3 dk (GrI) grubundaki hastalara maskenin uygulanmasýndan sonra normal solunumlarýna devam etmeleri söylendi.Dört derin nefes (GrII) grubundakilerden ise maksimal bir ekspirasyondan sonra maske sýkýca uygulanarak 4 kez söylenen zamanlarda maksimal nefes alýp vermeleri, sonra normal solunuma devam etmeleri istendi
Preoksijenasyon tamamlandýktan anestezi indüksiyonu yapýldý,
Anestezinin baþlangýcý ve tam kas paralizisinden sonra(60-90 sn), trakea tam olarak görülerek entübe edildi, tüp havaya açýk býrakýldý.Hastalar çalýþma sonuna kadar ventile edilmedi.
SpO2 nin %93 e indiði anda son veriler ve son kan gazý örneði alýndý, akciðeler %100 O2 ile ventile edilerek çalýþmaya son verildi

BULGULAR: Çalýþma 29 hasta ile tamamlandý.
Her iki gruptaki hastalarýn demografik verileri ve Htc düzeyleri açýsýndan anlamlý fark yoktu(p>0,05)Yaþ ortalamasý GrI için 65,8, Gr II için 65,2 idi
Hastalarda anestezi indüksiyonundan tam kas gevþemesi-apne zamanýna kadar geçen süreler benzerdi (p>0,05)
SpO2 deðerinin %97,95 ve 93 olduðu zamanlardaki hemodinamik verilerden KAH arasýnda istatistiksel fark bulunurken bu saturasyonlara ulaþým zamanlarý 4 derin nefes grubunda anlamlý olarak kýsa idi(p<0,001;p<0,01,p<0,05)
TARTIÞMA ve SONUÇ: Yaþlý hastalarda akciðerdeki fizyolojik deðiþimler akciðer reservlerini etkilemektedir
Çalýþmamýzda bu hasta grubunda vital kapasite solunumunun etkinliðinin azalmasý nedeniyle preoksijenasyon yöntemi olarak 3 dakikalýk normal tidal soluk yönteminin daha uygun olacaðý kanýsýna varýlmýþtýr