Efects Of Smoking On Postoperative Analgesia In Patients Undergoing Thoracic Surgery And Intervention Measures

BackgroundSmoking is One of the most serious public health problem in the world. It is well known that smoking is associated with chronic diseases, and long-term smoking can lead to nicotine dependence. Of approximately 23 million adults who undergo surgery every year worldwide, about 30% are current smokers required to stop smoking before surgery. The association between nicotine dependence and withdrawal and postoperative pain is a concern of anesthesiology research. Several studies have indicated that current smokers experience greater postoperative pain and require more analgesia than nonsmokers. Most studies have compared the postoperative pain of smokers and nonsmokers through clinical observations, and define smoking in terms of the daily amount of smoking and history of smoking. The association between degree of nicotine dependence and postoperative pain in smokers has not been specifically addressed.Nicotine dependence commonly has both physical and psychological components, and individual smokers exhibit each to various degrees. For some, physical dependence predominates whereas for others the dependence is mainly psychological, and withdrawal symptoms will differ depending on the level of nicotine dependence. We hypothesized that patients with different levels of nicotine dependence may require different amounts of postoperative opioid analgesia.Thoracic surgery often generates severe pain, which is considered one of the most severe forms and difficult to control after surgery. It is particularly important to optimize postoperative analgesia in highly-nicotine dependent patients. Lots of systemic and regional methods of analgesia have been described for post-thoracotomy pain. Dexmedetomidine, a new high selective α2-adrenoreceptor agonist, has sympatholytic, analgesic, sedative properties, with a lack of respiratory depression. It has been approved for use for sedation/analgesia in the intensive care unit and during surgery as an adjuvant anaesthetic. Some researchs had found that intra-operative dexmedetomidine could improve the effects of analgesia after abdominal surgery, minor surgery, lumbar laminectomy, or gynecological surgery. Study on the effects of intra-operative dexmedetomiding on postoperative pain in patients after thoracic surgery has not been published.The aim of this study was to investigate the effects of nicotine dependence on opioid requirements of patients after thoracic surgery, and investigate the efficacy and safety of administrating dexmedetomidine during the thoracic surgery in highly-nicotine dependent patients.PART I Effect Of Nicotine Dependence On Opioid Requirements Of Patients After Thoracic SurgeryObjective:To investigate the effect of nicotine dependence on required postoperative opioid administration in patients undergoing thoracic surgery.Methods:This retrospective study consisted of 215 male patients (112 nonsmokers, 103 smokers) who underwent thoracic surgery and received postoperative patient-controlled intravenous analgesia. Evaluations of nicotine dependence were based on results of Fagerstrom Test of Nicotine Dependence (FTND) questionnaires. Smokers were categorized as low-nicotine dependent (LD) (n= 58) or highly-nicotine dependent (HD, n= 45) with FTND scores< 6 or≥ 6, respectively. Pain intensity was assessed every 4 h after surgery, using the numerical rating scale (NRS). The cumulative amount of self-administered sufentanil at 24 and 48 h after surgery was recorded.Results:There were no significant differences in baseline clinical characteristics among the nonsmoker (NS), LD, and HD groups. The NRS scores and total amount of self-administered sufentanil were significantly higher in the HD and LD groups compared with the NS group, and were significantly higher in the HD group than in the LD group. The FTND scores positively correlated with the cumulative quantity of sufentanil. Postoperative complications such as nausea and vomiting, sedation, and respiratory depression did not significantly differ among the groups.Conclusions:Smokers had more severe postoperative pain and required a higher quantity of postoperative opioid than nonsmokers. With increasing nicotine dependence, postoperative pain severity and postoperative opioid requirement increased.PART Ⅱ The Effects Of Intra-operative Dexmedetoinidiiie On Postoperative Pain In Highly-nicotine Dependent Patients After Thoracic Surgery Objective: To investigate the effects of intra-operative dexmedetomidine on postoperative pain in highly-nicotine dependence patients after thoracic surgery.Methods:In this prospective, double-blind, randomised study, 100highly-nicotine dependent male patients who underwent thoracic surgery and received postoperative patient-controlled intravenous analgesia were randomized into two groups: dexmedetomidine(Group D) and saline group(Group C). Forty-six patients in the dexmedetomidine group and 48 in the saline group completed the study.Patients in the dexmedetomidine group were administered as a loading dose of 1μg/kg dexmedetomidine in 10 min, followed by a continuous infusion at 0.5μg /kg/h until 30 min before surgery end. The same volume saline was administered in the control group as that in the dexmedetomidine group. All Patients underwent tracheal intubatio or bronchial intubation for general anesthesia using a combination of inhalation anesthetics and intravenous agents. After surgery, patients were transferred to the post-anesthesia care unit(PACU). If necessary, patient were administered loading dose of sufentanil by anesthesiologist, patient controlled analgesia(PCA)started when rest numerical rating scale(NRS) <4. Patients,data were obtained,including dosage of sufentanil at Oh(arrived PACU immediately),1,4,8,12, 16, 20,24,28, 32, 36, 40, 44, 48 h after surgery. NRS scores at rest and with coughing were recorded at the same time points. If other analgesics were used,the dosage of 也ese analgesics was converted to the dosage of sufentanil based on equianalgesic dose ratios as previously described. Surgical data, analgesia-associated adverse effects and degree of satisfaction were obtained too.Results:1.There were no significant differences in general datas of patients and surgery between two groups(p>0.05).2.The cumulative dosage of sufentanil were significantly lower in Group D compared with the Group C during the 24 h after smgery(p<0.05). Compared with Group C,rest and with coughing NRS were significantly lower in Group D (P<0.05). There were no significant difference in sufentanil dosage and NRS after 24 h after surgery between the two groups (P>0.05).4. Compared with Group C,HR of Group D was lower(P<0.05),the variables of SBP and DBP were not signincant between the two groups(P>0.05). No patient experienced sedation or respiratory depression. The frequency of nausea and vomiting, the degree of satisflcation did not significantly differ among the groups(P>0.05).Condusion: Intra-operative dexmedetomidine had a ireduction in rest and with coughing NRS scores compared with placebo, had sufentanil-sparing effect during within 24 h after thoaracic surgery.