Please select the eligibility criteria that correspond to the clinical trial below.
Title: Effects of Two Different Anesthesia-analgesia Methods on the Incidence of Postoperative Delirium: a Multicenter, Randomized Controlled Trial
Brief Summary: Postoperative delirium is a common complication in elderly patients after surgery. Its occurrence is associated with worse outcomes. The pathophysiology of delirium remains poorly understood. However, an universal phenomenon is that delirium frequently occurs in elderly patients after major complicated surgery, but is rarely seen after minor ambulatory surgery (such as cataract surgery). This indicates that stress response produced by surgery might have an important role in the pathogenesis of delirium. It has been reported that, when compared with general anesthesia and postoperative intravenous analgesia, neuraxial anesthesia and analgesia reduced the occurrence of postoperative complications and mortality in high risk patients. Combined epidural-general anesthesia is frequently used in clinical practice. This anesthetic method provides advantages of both epidural and general anesthesia, i.e. it blocks the afferent pathway of nociceptive stimulus by neuraxial blockade during and after surgery, and allows patients to endure long-duration surgery without any awareness. The investigators hypothesize that combined epidural-general anesthesia and postoperative epidural analgesia can decrease the incidence of delirium in elderly patients after major surgery when compared with general anesthesia alone and postoperative intravenous analgesia.


Options:
A: Inclusion criteria:

1. elderly patients (age range 60-90 years);
2. scheduled to undergo noncardiac thoracic or abdominal surgery with an expected duration of 2 hours or longer. For those who undergo thoracoscopic or laparoscopic surgery, the expected length of incision must be 5 centimeters or more;
3. agree to receive patient-controlled postoperative analgesia.

Exclusion criteria (patients who meet any of the following criteria will be excluded):

1. previous history of schizophrenia, epilepsy or Parkinson disease, or unable to complete preoperative assessment due to severe dementia, language barrier or end-stage disease;
2. history of myocardial infarction within 3 months before surgery;
3. any contraindication to epidural anesthesia and analgesia, including abnormal vertebral anatomy, previous spinal trauma or surgery, severe chronic back pain, coagulation disorder (prothrombin time or activated partial prothrombin time longer than 1.5 times of the upper limit of normal, or platelet count of less than 80 × 10\^9/L), local infection near the site of puncture, and severe sepsis;
4. severe heart dysfunction (New York Heart Association functional classification 3 or above), hepatic insufficiency (Child-Pugh grades C), or renal insufficiency (serum creatinine of 442 μmol/L or above, with or without serum potassium of 6.5 mmol/L or above, or requirement of renal replacement therapy); or
5. any other conditions that were considered unsuitable for study participation.
B: Inclusion Criteria:

* Male or female subject aged over 75 years
* Admission for a scheduled surgery (i.e. all oncologic digestive surgery , ureterostomy, nephrectomy or cystectomy, total hip or knee replacement)
* Participation agreement

Exclusion Criteria:

* Patients with a progressive and/or poorly managed psychiatric pathology (patients with stabilized depression could be included in the study)
C: Inclusion Criteria:

* Patients 60 and older
* Competent to provide informed consent
* Undergoing major surgery (e.g., open cardiac surgery, open or thoracoscopic thoracic surgery, abdominal surgery, open urological surgery, open gynecological surgery, major orthopedic surgery, major vascular surgery including endovascular procedures, major ear, nose and throat surgery).

Exclusion Criteria:

* Patients with an allergy to ketamine
* Those in whom a significant elevation of blood pressure would constitute a serious hazard (e.g., pheochromocytoma, aortic dissection)
* Unable to provide informed consent
* Patients with drug misuse history (e.g., ketamine, cocaine, heroin, amphetamine, methamphetamine, MDMA, phencyclidine, lysergic acid, mescaline, psilocybin)
* Patients taking anti-psychotic medications (e.g., chlorpromazine, clozapine, olanzapine, risperidone, haloperidol, quetiapine, risperidone, paliperidone, amisulpride, sertindole)
* Patients with a weight outside the range 50 kg - 200 kg (110 lbs - 440 lbs)
D: Inclusion Criteria:

* Elderly patient (≥ 75 years)
* Patient with planned hip fracture surgery within 48 hours after the hip fracture
* Patient willing and able to complete the requirements of this study including the signature of the written informed consent

Exclusion Criteria:

* Patient suffering from multiple fractures, pelvic fractures proximal, pathological fractures, femur fractures (i.e., fractures of the middle or distal femur)
* Disabling neuropsychiatric disorders (severe dementia, Alzheimer's disease, schizophrenia, depression)
* Brain trauma within 12 months prior to selection, history of stroke with residuals
* Patient suffering from delirium (CAM diagnosis) at selection
* Patient who cannot complete the pre-operative mental tests (CAM and/or MMSE) of this clinical trial
* Patient with Mini-Mental State Examination (MMSE) score \< 24 at selection
* Patient known to susceptible to malignant hyperthermia
* Patient with elevated intra-cranial pressure
* Patient with a risk of high oxygen demand
* Patient with recent or ongoing myocardial infarction / damage
* Patient with severe cardiac failure, or patient with severe impaired left ventricular systolic function
* Patient with known severe lung and/or airway disease, or severe chronic respiratory insufficiency, or a sustained homecare oxygen therapy
* Contra-indication (serious illness or medical conditions) for general anaesthesia
* Known allergy or hypersensitivity to any drugs administered during this clinical trial
* Previous participation in this clinical trial
* Participation in another clinical trial within 4 weeks prior to selection
* History of alcohol or drug abuse or psychiatric disorders which would impair the understanding of the necessary information or render medically or legally unable to give written informed consent

Answer: A