1997 Fiscal Year Final Research Report Summary
Risk factors, mechanisms and therapy for postoperative nocturnal desaturations
| Project/Area Number |
08671714
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Chiba University |
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Principal Investigator |
ISONO Shiroh Chiba University School of medicine, Assistant, 医学部, 助手 (80212968)
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| Project Period (FY) |
1996 – 1997
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| Keywords | surgery / postoperative hypoxemia / sleep disordered breathing |
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| Research Abstract |
Severe postoperative hypoxemia during sleep may increase the risk of postoperative cardiovascular complications. We examined risk factors and mechanisms of postoperative nocturnal desaturations, and usefulness of oxygen therapy for the treatment was evaluated. We performed overnight oximetry preoperatively and during one night between the second and fourth postoperative days in patients undergoing major surgeries. We calculated oximetry parameters such as oxygen desaturation index (ODI : h^<-1>) defined as the number of oxygen desaturations exceeding 4% below the baseline, the percentage of time spent at SpO^2<90% (CT_<90>, %), and lowest SpO^2. Postoperatively, although change of ODI was insignificant, aggravation of CT_<90> and lowest SpO^2 were significant.
Multivariate analysis of possible risk factors for postoperative desaturations revealed that preoperative ODI and apnea witnessed by others were the variables highly correlated with postoperative ODI.We conclude that the presence of preoperative SDB is a significant risk factor for the development of severe postoperative desaturations during sleep.
Although administration of oxygen to patients with SDB postoperatively improved nocturnal oxygenation, heart rate variability due to repeated upper airway obstructions was not eliminated. In patients with severe SDB,oxygen therapy did not eliminate events of nocturnal desaturations, and prolonged duration of apnea in some cases. This indicates that oxygen therapy may not be appropriate for the treatment of postoperative nocturnal desaturations.
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