| Background and ObjectiveWith the increase of life expectancy of population in China, The aged undergoing surgical operations are gradually increasing following aging in our country. The surgery maybe bring benefit or risk. General anesthesia and surgical operation can cause damage of lung function in verying degrees, Which could result in postoperative hypoventilation and even hyoxemia. Because of the decline of respiratory function, elderly patients may happen postoperative complication easily such as pneumonia, atelectasis, respiratory failure. A statistics thinks that occurrence rate of pulmonary infection reached twenty percent after abdominal operations in elderly, so it has a strong impact on postoperative rehabilitation. Positive preventive measures should be take. In perioperative period, the protective measures for lung function remain a hot question in anesthesia field. Researches confirm that dexamethasone and edaravone and propofol have antioxidant and lung protective effect. But they are confined to experimentation on animals or the patients who need one-lung ventilation during operations. It has the concern that propofol infusion could influence lipid metabolism, even result in propofol infusion syndrome(PRIS). It is on the probing stage to optimize perioperative lung ventilation strategy.Dexmedetomidine which is high selective alpha2-adrenergic agonists, acts on the alpha2-adrenergic receptor distributing on Locus Coeruleus and spinal cord. So it has the effects including sedation, antianxiety, analgesia and balance anesthesia.Following the studys in a deep-going way, anti-inflammatory action and organ protection is being knew gradually. Research suggests that dexmedetomidine can decrease the levels of proinflammatory factor(IL-1?,TNF-?,IL-6,IL-4)in intraoperative and postoperative surgical patients. Otherwise, dexmedetomidine shows a protective effect to the lungs through reducing acute lung injury in animal experimental model. In this paper, by observing the influence in respiratory function of dexmedetomidine in elderly undergoing radical gastrectomy, author try to explore its mechanism of action, and provide reference for clinical medication.Materials and MethodsForty elderly patients undergoing radical gastrectomy in general anesthesia, ASA class?~?,were randomly divided into two groups(twenty patients for each group):dexmedetomidine group(group D) and control group(group C). In group D, a loading dose of dexmedetomidine 0.2?g/kg was injected into the vein before anesthesia induction, and followed by the dose of 0.4?g· kg-1·h-1 after anesthesia induction till30 minutes before the end of operation, the equal volume saline was given in group C,respectively. Blood samples were taken from radial artery before the injection of dexmedetomidine(T0), 30 minutes after the beginning of operation(T1), 30 minutes before the end of operation(T2), 3 minutes before extubation(T3), 12 hours after operation(T4) and 48 hours after operation(T5) to do arterial blood gas analysis. Pa O2 and Pa CO2 were recorded at each measuring point and calculate oxygenation index(Pa O2/Fi O2), alveolar–arterial difference(PA-a O2)and respiratory index(RI).Mean arterial pressure(MAP)and heart rate(HR) were recorded at T0-T5 time points.Postoperative delirium was assessed within 7 days after operation using Confusion Assessment Method(CAM).ResultsThe comparison of hemodynamics in patients with the preoperative basic value shows that before extubation MAP and HR in the two groups are increased, and at the same point, MAP in group C is higher than that in group D, the difference is statistically significant(P <0.05). After extubation measured values gradually returned to preoperative levels in two groups. Compared with group C, at T3 point, Pa O2/Fi O2 was increased in group D, the difference is statistically significant(P <0.05); PA-a O2?RI were decreased in group D, the difference is statistically significant(P <0.05).PA-a O2 at T4 point was also lower in group D than that in group C, the difference is statistically significant(P <0.05). Compared with group C, The incidence of postoperative delirium was significantly lower in group D, the difference is statistically significant(P <0.05).Conclusion Intraoperative use of dexmedetomidine at the dose of 0.4?g· kg-1·h-1can improve oxygenation and respiration function of elderly patients undergoing radical gastrectomy in anesthesia recovery period. It is likely to possess the potential advantage to prevent the postoperative pulmonary complications. Also,Dexmedetomidine significantly decreases the occurrence of delirium during the first 7days after surgery. |
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