The Incidence of Low Saturation by Pulse Oximetry in the Postanesthesia Care Unit / 대한마취과학회지

BACKGROUND: Patients are most likely to develop severe arterial desaturation during the early postoperative period. Respiratory complications in postanesthesia care unit (PACU) increase the risk of major adverse cardiac outcomes, unanticipated ICU admission or delay in PACU discharges. The increased use of inhalation agents with low blood : gas partition coefficient, intermediate-acting muscle relaxants and continuous pulse oximeter monitoring over the past 10 years may have altered the incidence of immediate postoperative hypoxemia. This study was undertaken to determine the overall incidence of immediate postoperative hypoxemia in PACU. METHODS: Hypoxemia was defined as a pulse oxygen saturation (SpO2) of less than 90% lasting for at least 20 sec. The occurrence of hypoxemia was documented and notified to the anesthesiologist by PACU nurses. The anesthesiologist recorded contributory factors and the management modalities used in patients with hypoxemia. RESULTS: The incidence of hypoxia was 3.5 per 1,000 patients after general anesthesia. Most hypoxemic events (88%) occurred during the first 5 minutes after arrival in PACU. Upper airway obstruction was the major contributory factor for hypoxemia (75.5%) and most of these patients recovered simply after a jaw thrust or the insertion of an oral or nasal airway. CONCLUSIONS: Postoperative hypoxemia does not occur often in PACU, but when it does, it is associated with major morbidity and increased medical costs. Therefore, oxygen supply is recommended in patients with risk factors of hypoxemia during transfer from operating rooms to PACU. Close monitoring of hypoxemia in PACU is needed in all patients after general anesthesia.

A comparison of arterial blood gas values depending on the use of endotracheal tube cuff in postanesthetic patients / 대한마취과학회지

An endotracheal tube (ETT) may be thought of as a mechanical burden to a spontaneously breathing patient because increases in airway resistance might result in increases in the work of breathing,when diameter of airway is decreased in the intubated patient compared with his own tracheal diameter. We hypothesized that air removal from ETT cuff would permit the airflow between ETT and tracheal wall and could make the airway resistance decrease. Postanesthetic patients after abdominal surgery were divided into two groups. ETT cuff was inflated in group 1 (n=25) and deflated in group 2 (n=25), while 5 l/min of oxygen was delivered through the ETT via a simple oxygen supplement device without a gas reservoir. The effects of balloon on gas exchange and respiratory pattern were evaluated at 5 and 30 minutes after admission to the recovery room. Postanesthetic PaO2 was increased compared to preanesthetic value with oxygen supply. PaCO2 values revealed no significant changes in preanesthetic and postanesthetic periods. Postanesthetic respiratory rate was increased significantly but there was no difference between two groups. However, there were three hypoxemic patients whose PaO2 were below 70mmHg in group 1. It was concluded that the use of balloon of ETT in postanesthetic recovery period might contribute to airway resistance and the work of breathing. Although almost of patients could make compensations to overcome the effects of balloon, there is a risk of postoperative hypoxemia if compensated inadequately.

Validity on Postoperative Routine Supplemental Oxygen Using Pules Oximetry-Determining factor on the Postoperative Arterial Hypoxemia / 대한마취과학회지

Routine use of supplemental oxygen(O2) in the recovery room traditionslly has been used to minimize the incidence of hypoxemia. However with the advent of continuous noninvasive monitoring by pulse oximetry is routine administration of O2 necessary? We hypothesized that administration O2 as needed based on pulse oximetry dats, would effect without compromieing patient care. And factors that might influence the incidence of post-operative hypoxemia were analyzed. On hundred thirty eight adult (> or = 18yrs) patients were enrolled in the study. During recovery room care, when O2 saturation(SpO2) was continuously more than 94%, no supplemental O2 was given. When SpO2 was less than 94%, supplemental O2 was given by face mask(O2 51/min). SpO2 and Aldrete score(AS) were measured at preoperatively, at the end of anesthesia, on arrival in the recovery room, at 10 min, 20 min and 30 min after arrival in the RR and at discharge. The results are as follows: 1) Supplemental O2 was unneeessary in the 55.8% of patient for the duration of the recovery room stay. 2) A significant multiple correlation was found between low SaO2 level, while breathing room air on arrivsl in the recovery room and preoperative SpO2, weight and Aldrete score on arrival in the recovery room. With the above results the authors concluded that in as much as pulse oximetry monitoring is now standard in the recovery room, administration O2 as need based on the pulse oximetry data would effect without compromising patient care, and that preoperative oxygen saturation and weight are the main factors influencing early postopertative hypoxemia in this study.

Hypoxemia after General Anesthesia in Children / 대한마취과학회지

Postoperative hypoxemia has been well known is adults but not in infants and children, although they are potentially more susceptible to airway closure and to disturbances in pulmonary gas exchange. We measured blood gas parameters of capillary blood in 30 cases of ASA physical status class l infants and children breathing room air, before and after general anesthesis for superficial surgical procedures. The blood samples were taken preoperatively, on arrival and 4~6 minutes later in the recovery room. The results are as follows: 1) The blood gas parameters on arrival in the recovery room showed significant change in pH nad PCO2(p<0.01) and increased PCO2(p<0.01) in comparison with preoperative gases. 2) The blood gas parameters checked at 4~6 minutes later in the recovery room showed insignificant differences from preoperative values of PO2 and SO2, but significantly increased PCO2 and decreased pH(p<0.01). 3) As a results of this study, it is suggested that for the safe management of patients, supplementary oxygen be provided for at least 10 minutes in the early recovery period to all pediatric patients.