Effects Of Prophylactic Infusion Of Hypertonic Saline Solution On Postoperative Delirium Of The Aged

Objective:Postoperative delirium（POD）is a common acute cerebral disorder syndrome,which is characterized by sudden and transient disturbances in cognitive function,psychomotor behaviors and sleep-wake disorders.POD can induce permanent cognitive impairment in severe cases.POD is associated with the release of a large number of inflammatory cytokines by the activation of the immune system in surgery.Aseptic surgery increases inflammatory mediators of serum and causes inflammation-mediated hippocampal-relatedcognitivedysfunction.Theup-regulationof CD14+CD16+monocytes expression is related to the systemic inflammatory response under pathological conditions such as trauma and shock.Reportedly,hypertonic saline solution can inhibit neutrophil adhesion,reduce the level of cytokines,and regulate the immune response.However,whether hypertonic saline solution can reduce the incidence of POD in elderly patients by improving systemic inflammatory response remains largely to be determined.This study aimed to evaluate the effects of prophylactic infusion of hypertonic saline solution on delirium after hip arthroplasty in elderly patients.Methods:Sixty geriatric patients aged 65-85 yr,with body mass index18-25 kg/m²,of American Society of Anesthesiologists physical statusⅡorⅢ,scheduled for elective unilateral total hip replacement,were divided into 2groups（n=30 each）:control group（group NS）and hypertonic saline solution group（group HS）.In the group NS,normal saline was intravenously infused at a dose of 4 ml/kg over 30 min before surgery,and the equal level volume of hypertonic sodium chloride hydroxyethyl starch 40 injection was given in group HS.To avoid electrolyte disorder,the level of K⁺,Na⁺and Ca²⁺in the arterial blood were measured before infusion and at 30,60 and 120 min after infusion(T_0-3).At T₀,before incision（T₄）and 30 min after surgery（T₅）,blood samples were taken from peripheral artery for determination of the concentrations of IL-1β,IL-6,TNF-α,IL-10 and S100βprotein.At T_0,4,5,the expression of CD14+CD16+monocytes was detected by flow cytometry.The Chinese version of nursing delirium screening scale（Nu-DESC）was used to assess the development of postoperative delirium at 1,2 and 3 d after operation.Results:Compared with T₀,the concentration of K⁺was significantly decreased,and the concentration of Na⁺was increased at T_1,2,2 in group HS（P<0.05）.There was no significant difference in the parameters mentioned above in group NS（P>0.05）.Compared with group NS,the concentration of K⁺was significantly decreased,and the concentration of Na⁺was increased at T_1,2,2 in group HS（P<0.05）.Compared with T₀,the concentrations of serum IL-6,IL-1β,TNF-αand S100βprotein were significantly increased and the concentration of serum IL-10 was decreased at T₅ in group NS（P<0.05）.Compared with T₀,the concentrations of serum IL-6,IL-1β,and TNF-αwere increased at T₅ in group HS（P<0.05）,and no significant change was found in the concentrations of serum IL-10 and S100βprotein（P>0.05）.Compared with group NS,the concentrations of serum IL-6,IL-1β,TNF-αand S100βprotein were significantly decreased and the concentration of serum IL-10 was increased at T₅ in group HS（P<0.05）.Compared with T₀,the proportion of CD14+CD16+monocytes increased at T₅ in two groups（P<0.05）.The proportion of CD14+CD16+monocytes was lower at T₅ in group HS than group NS（P<0.05）.Compared with group NS,the incidence of postoperative delirium was decreased in group HS（P<0.05）.Conclusions:Prophylactic infusion of hypertonic saline solution can improve postoperative delirium which may be related to the regulation of monocytes secreting inflammatory factors in elderly patients.