Effects of neurolept and epidural analgesia on cardiovascular function and tissue metabolism in the geriatric patient

Perioperative outcomes following preoperative epidural analgesia in hip fracture patients undergoing surgical repair: A systematic review

OBJECTIVE

To examine the effectiveness and safety of epidural analgesia in the presurgical period on hip fracture patients undergoing surgical repair.

DESIGN

Systematic review.

METHODS

The study protocol was registered with the PROSPERO systematic reviews register: CRD42019140396. Electronic databases were searched for randomized controlled trials comparing preoperative epidural analgesia to other forms of pain management in hip fracture patients. The primary outcomes included perioperative cardiac events and mortality. Pain, non-cardiac complications, and adverse effects were also examined as secondary outcomes. Heterogeneity of the included studies was assessed using the I2 statistic and a random-effects meta-analysis was conducted once sufficient homogeneity was demonstrated.

RESULTS

Four studies met the inclusion criteria, which included a total of 221 patients. Preoperative epidural analgesia resulted in fewer cardiac events, which was a reported outcome in two included studies (RR 0.30; 95% CI 0.14-0.63; I2 = 0%). Preoperative epidural analgesia was also associated with decreased perioperative mortality in a meta-analysis of two studies (RR 0.13; 95% CI 0.02-0.98; I2 = 0%). Pain was not pooled due to variability in assessment methods, but preoperative epidural analgesia was associated with reduced pain in all four studies.

CONCLUSIONS

Preoperative epidural analgesia for hip fracture may reduce perioperative cardiac events and mortality, but the number of included studies in this systematic review was low. More research should be done to determine the benefit of early epidural analgesia for hip fractured patients.

[Monitoring of mixed venous oxygen saturation in aortic surgery: value and limits]

This study aimed to determine perioperative changes in mixed venous oxygen saturation (SvO2) in patients undergoing aortic surgery. Continuous SvO2 monitoring was carried out using an Oximetrix pulmonary catheter. Fourteen patients were randomly assigned to 2 groups, group I (n = 7) patients being given a thoracic epidural anaesthetic with a supplementary general anaesthetic, and group II (n = 7) a general anaesthetic as usual. In both groups, SvO2 increased at induction. In group I patients, SvO2 decreased during surgery to less than 60% (n = 2) and less than 70% (n = 4). This fall was corrected by volume loading and intravenous ephedrine. The intraoperative decrease in SvO2 occuring in 2 group II patients was due to a fall in haematocrit in one, and a propranolol infusion in the other. Although patients in group I were all extubated early after the end of surgery (85 +/- 35 min), the lowest value of SvO2 after extubation was always greater than 60%. Patients undergoing aortic surgery under thoracic epidural anaesthesia can be extubated early, without markedly depressing peripheral reserves in oxygen extraction.

Effects of systemic morphine and epidural bupivacaine on postoperative oxygen consumption during rewarming

The alterations in hemodynamics and oxygen consumption as a consequence of continuous epidural infusions of bupivacaine at room temperature and conventionally administered morphine were studied during recovery from general anesthesia for total hip replacement. Twenty-four patients were randomized to receive either bupivacaine or morphine in the recovery room. The bupivacaine group received from 6 to 12 ml per hour of 0.25% bupivacaine epidurally. Patients in the morphine group received 0.1 mg/kg of morphine intramuscularly no more frequently than every 4 hours. A pulmonary artery flotation catheter was inserted into each patient to determine hemodynamics and oxygen consumption at three instances: before analgesia, when pulmonary artery blood temperature reached 36 degrees C, and when it reached 37 degrees C. During the rewarming there was a decrease in mean arterial blood pressure and the systemic vascular resistance index and an increase in heart rate. The whole body oxygen consumption index increased in the bupivacaine group at the last measuring point but was stable in the morphine group. There was no effect on the arterial-venous oxygen content difference in either group. At 37 degrees C, the cardiac index and oxygen consumption index were significantly higher in the bupivacaine group than in the morphine group. In contrast to regional analgesia, systemic morphine administration can partially antagonize cardiovascular response to postoperative rewarming because it induces a stable oxygen demand.

Thermal balance during transurethral resection of the prostate. A comparison of general anaesthesia and epidural analgesia

Heat loss during anaesthesia and surgery is a common problem. In patients with restricted cardio-pulmonary reserves this may endanger the postoperative outcome. In order to compare thermal balance we studied 25 men undergoing transurethral resection of the prostate (TURP), using either general anaesthesia (G.A.) or epidural analgesia (E.A.). Oxygen uptake, catecholamines, peripheral and central temperatures were followed in the per- and postoperative period. Heat production and total body heat were calculated from oxygen uptake and temperature measurements, respectively. Transurethral resection of the prostate resulted in a peroperative heat loss which was not influenced by the anaesthetic technique used and averaged 370 kJ during the first hour of surgery. G.A. reduced heat production while this was uninfluenced by E.A. After termination of general anaesthesia, oxygen uptake and plasma catecholamines increased, while no such changes could be detected using epidural analgesia. The ability to increase mean body temperature by increasing heat production was negatively correlated to age.

Hemodynamic and metabolic effects of ketamine anesthesia in the geriatric patient

The cardiovascular and metabolic effects of ketamine as the sole anesthetic agent for surgical correction of fractured neck of femur were studied in eight spontaneously breathing geriatric patients (mean age 83 years) before premedication, at the end of operation, and 15 min and 2 h after the end of anesthesia. Arterial blood pressure, cardiac index, left ventricular stroke work index and oxygen consumption increased during anesthesia but had returned to preoperative levels 15 min after the end of anesthesia. Vascular resistance, heart rate and stroke volume index were not significantly changed. During anesthesia, arterial carbon dioxide tension increased whereas arterial pH and arterial BE decreased. The levels of glucose and lactate increased in both blood and skeletal muscle during anesthesia and remained elevated throughout the period studied but the lactate:pyruvate ratio was unchanged. High energy phosphagen levels in skeletal muscle did not change. Ketamine anesthesia in the spontaneously breathing geriatric patient induces cardiovascular stimulation and metabolic changes indicative of an increased sympathetic stimulation, whereas respiration is slightly depressed. The magnitude of these changes is, however, small and it thus seems that ketamine can be safely used as the sole anesthetic agent for hip fracture surgery in the average geriatric patient.