Pathophysiology of post-operative cognitive dysfunction: current hypotheses

Post-operative cognitive dysfunction (POCD) has been reported after a variety of surgical procedures. POCD is associated with a decline in performance of activities of daily living of elderly patients and can cause substantial damage to family and/or to social support systems. The incidence of POCD in the first week after surgery is 23% in patients between 60 and 69 years of age and 29% in patients older than 70. Cognitive dysfunction was still present in 14% of patients over 70 at three month after surgery. The risk of POCD increases with age, and the type of surgery is also important since there is very low incidence of POCD after minor surgery. For many years, it has been known that general anaesthesia is associated with persistent changes in gene expression in the brain for at least 72 hours. These observed modifications suggest an interesting hypothesis to explain the side effects of anaesthetic agents on cognitive dysfunction, particularly in the elderly. The inflammatory response to surgery is consistent with the hypothesis that inflammation contributes to cognitive decline in the elderly. Most of the drugs administered during anaesthesia interact with the cerebral cholinergic system, which seems to be impaired with ageing. One can hypothesize that this cholinergic dysfunction is a potent factor in the pathogenesis of POCD. These findings have implications for the information provided before obtaining consent from elderly patients prior to surgery; a careful evaluation of mental status is mandatory for all elderly patients undergoing general anaesthesia. Perioperative physicians should be familiar with the prevention, diagnosis, and management of postoperative cognitive dysfunction.     

Postoperative cognitive dysfunction (POCD): strategy of prevention, assessment and management

The femoral neck fracture is a major cause of morbidity and mortality in the elderly. The etiology of cognitive impairment observed in this population of aged patient seems to be multifactorial. In the strategy of prevention, elderly patient must have the clearer information dealing with the postoperative cognitive dysfunction. This would reduce the incidence of POCD and some cognitive complaints, which often reflect the anxiety of the elderly patient facing the possibility of cognitive impairment. During the anaesthesia consultation, it seems important to assess the cognitive function of this elderly patient (like using neuropsycholgical scale as the MMSE) and to identify associated risk factors of cognitive dysfunction. The management of cognitive disorders should be multidisciplinary, the anesthesiologist being the main referent, in collaboration with the geriatrician and the surgeon. In the clinical setting of femoral neck fracture in the elderly, this multimodal management (pain, nutrition, functional rehabilitation to make these patients autonomous as quickly as possible), seems to improve the functional prognosis and to have the observed POCD decreased.     

Dysfonctions cognitives postopératoires : stratégie de prévention, de dépistage et de prise en charge

The femoral neck fracture is a major cause of morbidity and mortality in the elderly. The etiology of cognitive impairment observed in this population of aged patient seems to be multifactorial. In the strategy of prevention, elderly patient must have the clearer information dealing with the postoperative cognitive dysfunction. This would reduce the incidence of POCD and some cognitive complaints, which often reflect the anxiety of the elderly patient facing the possibility of cognitive impairment. During the anaesthesia consultation, it seems important to assess the cognitive function of this elderly patient (like using neuropsycholgical scale as the MMSE) and to identify associated risk factors of cognitive dysfunction. The management of cognitive disorders should be multidisciplinary, the anesthesiologist being the main referent, in collaboration with the geriatrician and the surgeon. In the clinical setting of femoral neck fracture in the elderly, this multimodal management (pain, nutrition, functional rehabilitation to make these patients autonomous as quickly as possible), seems to improve the functional prognosis and to have the observed POCD decreased.     

Thrombolyse postopératoire immédiate dans un contexte d’accident vasculaire sylvien gauche

Intravenous thrombolytic therapy for ischemic stroke was performed on a 75-year-old patient at recovery from cervicocephalic superficial surgery. The patient recovered totally from ischemic stroke and no neurologic sequelae was observed. Thrombolytic therapy must be performed in an intensive care unit in order to manage some bleeding events which can occur.     

Central cholinergic depletion induced by 192 IgG-Saporin alleviates the sedative effects of propofol in rats

We examined the effect of central cholinergic depletion on thesedative potency of propofol in rats. Depletion was producedby intracerebroventricular administration of an immunotoxinspecific to cholinergic neurones (192 IgG-Saporin; 2 µg).As a result of this lesion, acetylcholine concentration wasreduced by about 40% in the frontoparietal cortex and in thehippocampus but was essentially normal in the striatum and cerebellum.Sedation in rats was assessed as the decrease in locomotor activity.Sedative potency of propofol (30 mg kg^–1 i.p.) was reducedby about 50% in rats who received the injection of 192 IgG-Saporinas compared to controls. These results show that a central cholinergicdepletion alleviates the sedative effect of propofol, and indicatesthat basal forebrain cholinergic neurones might mediate partof the sedative/hypnotic effects of propofol. Br J Anaesth 2000; 85: 869–73     

Anesthésie locorégionale chez les patients spastiques

The use of peripheral nerve blocks in the assessment of the spastic patient is an important tool of the therapeutic care in the field of rehabilitation. The main role of the anesthesiologist is to perform selective nerve block of the upper and lower limb in order to mimic transient and reversible motor paralysis. The goal of this regional anesthesia is to define the best therapeutic strategy to improve the comfort, nursing and/or decrease pain of these patients. Ultrasound guidance combined with nerve stimulation seems to be an attractive tool to perform, notably selective nerve block. The anesthesiologists have an important role in this multidisciplinary approach. Use of regional anesthesia is going to provide the optimal therapeutic strategy for spastic patients.