Application value of dexmedetomidine in anesthesia for elderly patients undergoing radical colon cancer surgery.

BACKGROUND: Colon cancer presents a substantial risk to the well-being of elderly people worldwide. With advancements in medical technology, surgical treatment has become the primary approach for managing colon cancer patients. However, due to age-related physiological changes, especially a decline in cognitive function, older patients are more susceptible to the effects of surgery and anesthesia, increasing the relative risk of postoperative cognitive dysfunction (POCD). Therefore, in the surgical treatment of elderly patients with colon cancer, it is of paramount importance to select an appropriate anesthetic approach to reduce the occurrence of POCD, protect brain function, and improve surgical success rates. AIM: To explore the value of dexmedetomidine (Dex) in anesthesia for elderly patients undergoing radical colon cancer surgery. METHODS: One hundred and seventeen patients with colon cancer who underwent elective surgery under general anesthesia were selected and divided into two groups: A and B. Group A received Dex before anesthesia induction, and B group received an equivalent amount of normal saline. Changes in the mini-mental state examination, regional cerebral oxygen saturation (rSO2), bispectral index, glucose uptake rate (GluER), lactate production rate (LacPR), serum S100ß and neuron-specific enolase (NSE), POCD, and adverse anesthesia reactions were compared between the two groups. RESULTS: Surgical duration, duration of anesthesia, and intraoperative blood loss were comparable between the two groups (P > 0.05). The overall dosage of anesthetic drugs used in group A, including propofol and remifentanil, was significantly lower than that used in group B (P < 0.05). Group A exhibited higher rSO2 values at the time of endotracheal intubation, 30 min after the start of surgery, and immediately after extubation, higher GluER values and lower LacPR values at the time of endotracheal intubation, 30 min after the start of surgery, immediately after extubation, and 5 min after extubation (P < 0.05). Group A exhibited lower levels of serum S100ß and NSE 24 h postoperatively and a lower incidence of cognitive dysfunction on the 1st and 5th postoperative days (P < 0.05). CONCLUSION: The use of Dex in elderly patients undergoing radical colon cancer surgery helps maintain rSO2 Levels and reduce cerebral metabolic levels and the incidence of anesthesia- and surgery-induced cognitive dysfunction.

K(ATP) channels and MPTP are involved in the cardioprotection bestowed by chronic intermittent hypobaric hypoxia in the developing rat.

The aim of this study was to explore the mechanism underlying the cardioprotection bestowed by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in developing rats. Neonatal male rats were subjected to CIHH treatments that simulated an altitude of 3000 m a.s.l. for 28 days (CIHH28) and 42 days (CIHH42), respectively, or no treatment (control). The left ventricular function of isolated hearts was evaluated. The ultra-microstructure, superoxide dismutase (SOD) activity and total anti-oxidation capacity (TAC) of the myocardium were determined. The basic left ventricular function remained unchanged in CIHH rats, except for an increased coronary flow. The recovery of cardiac function from I/R, however, was much better in CIHH rats than in control rats. Compared to control rats, CIHH rats had much higher SOD levels and TAC, and the ultra-microstructure damage to mitochondria was considerably less. The cardiac protection of CIHH was canceled out by glibenclamide, an inhibitor of the ATP-sensitive potassium (K(ATP)) channel, 5-hydroxydecanoate, an inhibitor of mitochondrial K(ATP) (mitoKATP), and atractyloside, an opener of the mitochondrial permeability transition pore (MPTP). To the contrary, diazoxide, an opener of mitoKATP, and cyclosporin A, a blocker of MPTP opening, induced cardioprotection in control rats. These results suggest that CIHH protects the heart against I/R injury in developing rats through opening of the K(ATP) channel and inhibiting of opening of the MPTP.

Spinal anaesthesia with low-dose bupivacaine in marginally hyperbaric solutions for caesarean section: A randomised controlled trial.

BACKGROUND: Conventional hyperbaric spinal anaesthesia solution (SAS) with 8% glucose and low-dose bupivacaine may reduce the incidence of hypotension in caesarean section compared to standard doses, and marginally hyperbaric SAS (≤0.8% glucose) can induce a lower block level and a lower incidence of hypotension in nonobstetric patients than conventional 8% glucose SAS. OBJECTIVE: The objective of this study was to evaluate the clinical efficacy of marginally hyperbaric low-dose bupivacaine solutions used for spinal anaesthesia during caesarean section. DESIGN: A randomised, controlled clinical trial. SETTING: Single medical centre. PATIENTS: One hundred twenty women scheduled for elective caesarean section were randomised into four groups. INTERVENTIONS: Caesarean section after combined spinal-epidural anaesthesia using hyperbaric preparations of low-dose SAS (7.2 mg bupivacaine and 2 µg 1.6 ml sufentanil in one of the following: 8%, 0.8%, 0.5% or 0.33% glucose solution. MAIN OUTCOME MEASURES: The dermatomal sensory block and degree of motor block of the lower extremities and adverse effects of anaesthesia were recorded. RESULTS: The maximum cephalad sensory block level and the incidence of hypotension decreased as the density of SAS fell (T1, T2, T4 and T6, P < 0.001; 48.3, 30, 13.3 and 10.3%, P = 0.003). The incidence of shivering reduced with decreasing density of SAS (P < 0.05). There was no significant difference in the quality of anaesthesia (efficacy of motor block and sensory block) between the groups (P > 0.05). CONCLUSION: Compared with conventional 8% glucose hyperbaric SAS, marginally hyperbaric (0.5 or 0.33% glucose) low-dose bupivacaine solutions led to a significantly lower height of cephalad spread and incidence of hypotension with no impact on the efficacy of spinal anaesthesia for caesarean section.

Polydatin attenuates ischemia/reperfusion-induced apoptosis in myocardium of the rat.

The aim of the present study was to investigate the effect of polydatin on apoptosis induced by ischemia/reperfusion (I/R) in rat myocardium and to explore the underlying mechanism. Adult male Sprague-Dawley (SD) rats were randomly divided into control, I/R and polydatin (50 mumol/L) groups. On the Langendorff apparatus, isolated rat heart was subjected to 30-min global ischemia followed by 60-min reperfusion. TUNEL labeling and flow cytometric techniques were used for the measurement of apoptosis and the expression of Bcl-2 and Bax protein in cardiomyocytes of rat. The results showed: (1) Compared with those in the control group, the number of TUNEL-positive cells and apoptosis rate were increased in I/R group; (2) Compared with that in the I/R group, the number of TUNEL-positive cells was significantly decreased in the polydatin group [(18.1+/-4.0)% vs (35.1+/-5.4)%, P<0.01]; (3) Apoptosis rate assayed by flow cytometry in I/R group was significantly higher than that in polydatin group [(15.43+/-4.55)% vs (8.66+/-3.18)%, P<0.01]; (4) Expression level of Bax protein was higher in I/R group than that in polydatin group (P<0.05), while the level of Bcl-2 protein and Bcl-2/Bax ratio were higher in polydatin group than those in I/R group (P<0.05, P<0.01), respectively. The results obtained suggest that polydatin exerts an inhibitory effect on I/R-induced apoptosis through increasing Bcl-2 protein expression and decreasing Bax protein expression in myocardium of the rat.

Comparison of the effects of chronic intermittent hypobaric hypoxia and continuous hypobaric hypoxia on hemodynamics in rats.

The aim of this study is to investigate the effects of chronic intermittent hypobaric hypoxia (IHH) and chronic continuous hypobaric hypoxia (CHH) on hemodynamics under basic normoxia and acute hypoxia conditions and to find the difference of two types of chronic hypoxia. Forty adult male Sprague-Dawley (SD) rats were randomly divided into 5 groups: Control group (CON), 28 days IHH group (IHH28), 42 days IHH group (IHH42), 28 days CHH group (CHH28) and 42 days CHH group (CHH42). The rats in IHH groups were treated with intermittent hypoxia (11.1% O2) mimicking 5 000 m altitude in a hypobaric chamber for 28 or 42 d, 6 h a day, respectively. The rats in CHH groups lived in the hypobaric chamber with the same degree of hypoxia like IHH rats except half an hour in normoxia each day for feeding and cleaning. The body weight of rats was measured once a week. The parameters in hemodynamics, such as mean artery blood pressure (MAP), heart rate (HR), left ventricular systolic pressure (LVSP), maximum change rate of left ventricular pressure (+/-LVdP/dt(max)) were recorded under basic normoxia and acute hypoxia conditions through catheterization technique. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in myocardium of rats were measured by biochemical method. The weights of whole heart, left and right ventricles were measured separately. The results showed: (1) The basic HR and MAP in CHH42 rats were lower than those in CON, IHH and CHH28 rats (P<0.05). (2) IHH showed a cardioprotection against acute hypoxia and reoxygenation injury, manifested as the result that the changes of HR, MAP, LVSP, and +/- LVdP/dt(max) were smaller than those in CON rats during acute hypoxia and reoxygenation. CHH showed a rather strong cardioprotection during acute hypoxia, manifested as the result that the decreases of HR, MAP, LVSP, and +/- LVdP/dt(max)were much smaller, but it did damage during reoxygenation, manifested as the result that the recovery of hemodynamics was the worst among three groups (P<0.05). (3) The antioxygenation of heart was increased in both IHH and CHH rats compared with that in CON rats manifested by the increased SOD activity and decreased MDA content (P<0.05, P<0.01). (4) IHH had no effect on heart weight, but CHH rats showed an obvious right ventricular hypertrophy compared with CON and IHH animals (P<0.01). The result indicates that IHH can induce a more effective cardioprotection with no much side effect, which might have a potential value for practical use.