Determination of minimum alveolar concentration and cardiovascular effects of desflurane in positive-pressure ventilated sheep

Application of different concentrations of sevoflurane with remifentanil in radical surgery for gastrointestinal tumors: Effects on intraoperative hemodynamics and postoperative anesthetic recovery

BACKGROUND

The combination of remifentanil and sevoflurane can provide patients with sufficient analgesic and sedative effects. Anesthesia for gastrointestinal tumor surgery not only needs to reach the required depth of anesthesia for surgery, but also needs to reduce the surgical stress to ensure rapid recovery after surgery.

AIM

To explore the application of different concentrations of sevoflurane with remifentanil in radical surgery for gastrointestinal tumors and the effects on intraoperative hemodynamics and postoperative anesthesia recovery.

METHODS

Eighty-six patients undergoing radical surgery for gastrointestinal tumors at our hospital from January 2020 to December 2021 were selected and divided into two groups by random number table method, with 43 cases in each group. Sevoflurane at a 1.0 minimum alveolar effective concentration (MAC) with remifentanil was adopted in group A, and 1.5 MAC sevoflurane with remifentanil was adopted in group B. The quality of anesthesia, intraoperative hemodynamics [mean arterial pressure (MAP) and heart rate (HR)], cerebral oxygen metabolism [cerebral oxygen uptake rate (CERO₂) and jugular venous oxygen content (SjvO₂)] at different time points, adverse events during anesthesia maintenance, and postoperative anesthesia recovery were recorded in the two groups.

RESULTS

During maintenance of anesthesia, the rate of adjustment of remifentanil pumping rate was lower in group A than in group B (32.56% vs 67.44%, P < 0.05). There was no significant difference in HR or MAP at each time point between the two groups (P > 0.05), and both HR and MAP were within the normal range. There was no significant difference in CERO₂ or SjvO₂ at each time point between the two groups (P > 0.05); CERO₂ at T2, T3, T4, T5, and T6 in both groups was lower than that at T1, and SjvO₂ was higher than that at T1 (P < 0.05). The incidence of hypotension during anesthesia maintenance in group A was lower than that in group B (P < 0.05). The times to open eyes on command, recovery of spontaneous breathing, extubation, and exit from the room during anesthesia awakening were shorter in group A than in group B (P < 0.05).

CONCLUSION

Both 1.0 MAC and 1.5 MAC sevoflurane can meet the demand for anesthesia maintenance in surgery for radical gastrointestinal tumors; however, 1.0 MAC sevoflurane can provide better quality of anesthesia maintenance with less effect on cerebral oxygen metabolism, which can significantly improve the quality of awakening and shorten the anesthesia awakening time, and is conducive to faster clinical turnaround.

An Overview of the Implications for Perianesthesia Nurses in terms of Intraoperative Changes in Temperature and Factors Associated with Unintentional Postoperative Hypothermia

Patients undergo surgery and anaesthesia on a daily basis across the United States and throughout the world. A major source of worry for these patients continues to be inadvertent hypothermia, once core temperature <36°C (96.8°F). Despite well-documented adverse physiological consequences, anaesthesia nurses continue to have a difficult task in keeping patient warmth pre-/peri-/post-surgical procedure. Thermostasis within postoperative patient necessitates the collaboration of many individuals. In order to provide safe and high-quality treatment, it is essential to use the most up-to-date data to guide therapeutic procedures targeted at achieving balance body temperature in surgical patients. Providing a review of the physiology of perioperative temperature variations and the comorbidities linked with accidental intraoperative hypothermia, this article will also provide preventive and treatment methods.

The Determination of the Minimum Anaesthetic Concentration of Halothane in the Rock Dove (Columba livia) Using an Electrical Stimulus

This study aims to determine the minimum anaesthetic concentration (MAC) of halothane in the Rock Dove using electrical stimulus. Seven Rock Doves are anaesthetised with halothane, and the MAC is determined using the bracketing method. An electrical stimulus (two single pulses and two five-second stimuli, all separated by five-second pauses; 30 Hz, 30 V, 7.5 ms) is applied to the legs via subcutaneous electrodes. A maximum of eight periods of electrical stimulation, each with a preceding 15 min stable phase, is applied to each bird. If the non-reflexive movement occurred following stimulation, the end-tidal halothane (Fe’Hal) is increased by 10% before the next stimulus delivery. If no movement occurred, Fe’Hal is decreased by 10%. The MAC is the average of the highest concentration that allowed movement and the lowest that prevented movement. Physiological variables and ventilatory settings are recorded every five minutes. The current delivered is calculated offline. The mean ± SD MAC of halothane is 1.62 ± 0.29%, calculated from five birds. During the entire anaesthesia, all birds had cardiac arrhythmias —with three having sporadic recurrent periods of prolonged ventricular standstill followed by marked sinus tachycardia. The mean recorded voltage and calculated current and resistance are 27.6 ± 2.7 V, 20.3 ± 7.3 mAmp and 1.6 ± 0.9 kΩ, respectively. The advantage of halothane for prolonged anaesthesia in Rock Doves may be limited when noxious stimulation is used, due to the development of severe ventricular arrhythmias.