Anesthesia Induction Period Research Articles

Hemodynamic Influences of Remimazolam Versus Propofol During the Induction Period of General Anesthesia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND: Remimazolam is a novel ultrashort-effect benzodiazepine. In 2020, the US Food and Drug Administration approved it for procedural sedation. Remimazolam is beneficial for consistent sedation and quick recovery in painless gastrointestinal endoscopy. Propofol is one of the most commonly used intravenous anesthetics in clinical practice. Recently, only a few studies have compared propofol with remimazolam for general anesthesia induction. OBJECTIVES: The purpose of our systematic review and meta-analysis was to compare the hemodynamic effects of remimazolam and propofol during the induction of general anesthesia. STUDY DESIGN: Systematic review and meta-analysis of randomized, controlled trials. METHODS: The authors retrieved the PubMed, Embase, Cochrane Library, and Web of Science databases for studies published through September 30, 2022, which reported relevant prospective randomized controlled trials (RCTs) comparing remimazolam with propofol for general anesthesia. The primary outcome was hemodynamic changes, including the absolute value of fluctuation of mean arterial pressure (delta MAP) and heart rate delta HR). The secondary outcomes were the following 2 indicators: the occurrence of total adverse events and the quality of recovery from general anesthesia at 24 hours postsurgery. RevMan 5.4.1 (The Nordic Cochrane Centre for The Cochrane Collaboration) and trial sequential analysis were used to execute the statistical analyses. The different domains of bias were judged by the Cochrane risk of the bias assessment tool. RESULTS: The authors identified 189 papers in PubMed, Embase, Cochrane Library, and Web of Science. Eight articles with 964 patients were selected. The included studies had moderate quality. For primary outcomes, the lower delta HR (mean difference [MD] = -4.99; 95% CI, -7.97 to -2.00; I² = 41.6%; P = 0.001] and delta MAP (MD = -5.91; 95% CI. -8.57 to -3.24; I² = 0%; P < 0.0001) represent more stable hemodynamic characteristics in the remimazolam group. Regarding secondary outcomes, a considerably lower incidence of total adverse events was noted in the remimazolam group than that for the propofol group (odds ratio [OR] = 0.40; 95% CI, 0.28 to 0.58; I² = 63%; P < 0.00001). In comparison to the propofol group, remimazolam achieved an advantage score of quality of recovery -15 in 24 hours postsurgery (MD = 5.31, 95% CI, 1.51 to 9.12; I² = 87%; P = 0.006). LIMITATION: Firstly, there are only a handful of published RCTs on the administration of remimazolam in general anesthesia. In addition, due to patient privacy, we could not extract individual patient data, therefore we could not combine and assess any variations in patient characteristics. CONCLUSION: Evidence suggests that remimazolam has a lower hemodynamic effect during general anesthesia and fewer perioperative adverse effects after general anesthesia than propofol; however, which agent is superior regarding quality benefit in postoperative recovery based on the studies included here remains inconclusive. Additional RCTs with updated meta-analyses to enlarge the sample size and properly analyze the benefit-to-risk ratio to patients are needed to determine the evidence for such a relatively new medicine. KEY WORDS: Remimazolam, propofol, general anesthesia, hemodynamic, adult

A Collection of Studies on Anesthesia Modalities, Anesthetic Drugs and Circulatory Stability in Elderly Patients

With the increase in the proportion of elderly population in the society, China is gradually entering an aging society. Elderly patients may require anesthesia during medical treatment, and considering the relatively high surgical risk of elderly patients, comprehensive consideration must be given to the selection of anesthesia and the use of anesthetic drugs. Induction of general anesthesia is a process in which patients undergo reversible drug inhibition from a physiological state to a surgically operable anesthesia state within a short period of time, but tracheal intubation and anesthesia inhibition can trigger cardiovascular reactions, especially in elderly patients with poor circulatory function, which can lead to hemodynamic fluctuations and affect the stability of circulatory function. As elderly patients age, their organ function decreases, and their reserve function deficiency under anesthetic stress can increase the risk of adverse cardiovascular events. The hemodynamic fluctuations of patients during the induction period of general anesthesia are large, and it is important to reduce the hemodynamic fluctuations and maintain the stability of circulatory function to improve the safety of surgery. At present, the commonly used methods for induction of general anesthesia include manual intravenous push, target-controlled infusion and constant-rate infusion by infusion pump, and the commonly used drugs for induction of general anesthesia include intravenous sedative anesthetics, intravenous analgesics, muscle relaxants and inhaled anesthetics. Based on this paper, we analyze the effects of general anesthesia, epidural anesthesia, lumbar anesthesia, and epidural anesthesia in the application of surgery in elderly patients and general anesthesia induction in the circulatory stability of elderly patients for a review, in order to more accurately and better guide further clinical anesthesia research.

Thermodynamic Interpretation of a Machine-Learning-Based Response Surface Model and Its Application to Pharmacodynamic Synergy between Propofol and Opioids

Propofol and fentanyl are commonly used agents for the induction of anesthesia, and are often associated with hemodynamic disturbances. Understanding pharmacodynamic impacts is vital for parasympathetic and sympathetic tones during the anesthesia induction period. Inspired by the thermodynamic interaction between drug concentrations and effects, we established a machine-learning-based response surface model (MLRSM) to address this predicament. Then, we investigated and modeled the biomedical phenomena in the autonomic nervous system. Our study prospectively enrolled 60 patients, and the participants were assigned to two groups randomly and equally. Group 1 received propofol first, followed by fentanyl, and the drug sequence followed an inverse procedure in Group 2. Then, we extracted and analyzed the spectrograms of electrocardiography (ECG) and pulse photoplethysmography (PPG) signals after induction of propofol and fentanyl. Eventually, we utilized the proposed MLRSM to evaluate the relationship between anesthetics and the integrity/balance of sympathetic and parasympathetic activity by employing the power of high-frequency (HF) and low-frequency (LF) bands and PPG amplitude (PPGA). It is worth emphasizing that the proposed MLRSM exhibits a similar mathematical form to the conventional Greco model, but with better computational performance. Furthermore, the MLRSM has a theoretical foundation and flexibility for arbitrary numbers of drug combinations. The modeling results are consistent with the previous literature. We employed the bootstrap algorithm to inspect the results’ consistency and measure the various statistical fluctuations. Then, the comparison between the modeling and the bootstrapping results was used to validate the statistical stability and the feasibility of the proposed MLRSM.

Pulmonary Artery Pressure and Variations in Arterial Blood Pressure During the Induction Period of General Anesthesia in Elderly Patients.

To determine the correlation of old age, pulmonary artery pressure (PAP) and mean arterial blood pressure (MABP) during anesthetic induction in elderly patients. Prospective cohort study. Central Hospital affiliated to Chongqing Medical University from September 2016 to September 2019. A total of 75 elderly patients with pulmonary hypertension, who underwent surgery under general anesthesia, were inducted. Each 25 patients were allocated into 65-74 years, 75-84 years, and ≥85 years groups. PAP was invasively measured using a right heart floating catheter before induction, while MAP was measured using an invasive radial artery catheter at one minute before and within five minutes after anesthetic induction. PAP and PAMP, both increased with age (p <0.001). MAP at one minute before induction significantly increased with aging, while MAP measured at 1, 3 and 5 minutes after anesthetic induction, exhibited tendencies of significant decrease with aging (p <0.05). The correlation analysis results revealed that mean MAP during anesthesia induction was significantly associated with PASP before induction (r = -0.384 and -0.532 for Kendall and Spearman correlation analyses; both p<0.05). Increased PAP may be involved in the association between with aging and increased risk of hypotension during induction. Key Words: General anesthesia, Hypotension, Pulmonary arterial blood pressure, Old age.

Comparison of the anesthesia effects of ketamine, dexmedetomidine and tiletamine-zolazepam with or without tramadol in cats

This study investigated the analgesia effects of intramuscular injection of ketamine, dexmedetomidine and tiletamine-zolazepam combined with tramadol (KDZT) and compared the efficacy of this combination with that of ketamine, dexmedetomidine and tiletamine-zolazepam (KDZ) in Chinese local mongrel cats. Ten cats were tested twice as a comparison between the two groups, and the interval between the two groups was more than a week. The animals received ketamine (10 mg/kg), dexmedetomidine (10 μg/kg) and zoletil (5 mg/kg) combined with or without tramadol (2 mg/kg) for anesthesia in separate tests. Heart rate, respiration rate, non-invasive systolic pressure, hemoglobin oxygen saturation, rectal temperature, subjective pain scores and venous blood-gas were measured simultaneously. The induction time, recovery time of the righting reflex, standing and walking, the time during the anesthesia period were recorded. Cardiopulmonary variables changed after injection, some of which were significantly different from baselines before anesthesia induction. Values regarding blood gas changed after intramuscular administration, and significant differences were found between two groups at one of the timepoints. Both KDZT and KDZ provided adequate analgesia in cats. The induction period of two anesthetic mixtures was within 1-3 min and could effectively maintain anesthesia for 75-175 min. The change of physiological parameters remained within a biologically acceptable range and was not significantly different between the two groups. The use of KDZT resulted in better anesthesia, with shorter anesthesia induction period and longer anesthesia period compared with KDZ. No side effects were observed, no rescue analgesic was required.

A small dose of dezocine suppresses remifentanil-induced cough in general anesthesia induction: a prospective, randomized, controlled study

BackgroundThe aim of this prospective randomized controlled study was to evaluate whether pretreatment with a small dose of dezocine could prevent remifentanil-induced cough in general anesthesia induction.Trial designa prospective, randomized, controlled study.MethodsA total of 210 patients receiving elective operative hysteroscopy from December 2018 to April 2019 were enrolled in the present study. They were randomly equally separated into dezocine group (n = 105) and control group (n = 105). Patients were intravenously pre-administrated with dezocine 0.03 mg/kg (diluted to 5 mL) or the same volume of normal saline 1 min prior to remifentanil infusion. One minute later, intravenous injection of propofol 1.5 mg/kg and cisatracurium 0.1 mg/kg were given to all patients for induction of general anesthesia. The counts of coughs occurred during the anesthesia induction period were recorded and the severity of cough was scaled.ResultsThere were 7 cases of mild cough in dezocine group and 18 cases of mild cough, 12 cases of moderate cough and 4 cases of severe cough in control group. The incidence rate of cough was significantly lower and the severity of cough was obviously relieved in dezocine group compared to control group (6.67% vs. 32.38%, P < 0.001). The two groups were not significantly different in heart rate and mean arterial pressure before the induction, before and after the intubation, and in operating time and postoperative visual analog scale pain scores.ConclusionThis study recommends the efficacy and safety of a pretreatment with a small dose of dezocine in reducing remifentanil-induced cough during general anesthesia.Trial RegistrationChiCTR2000032035.Date of registration: Retrospectively registered on 2020/04/18.

Does uncontrolled diabetes mellitus affect cerebral hemodynamics in heart surgery?

In this study, we aimed to investigate the effects of poor blood glucose control on the intraoperative cerebral system in patients undergoing coronary artery bypass grafting using various neuromonitors. Between January 2011 and December 2011, a total of 40 adult patients (31 males, 9 females; mean age 58.8±9.2 years; range, 38 to 78 years) who were scheduled for elective coronary artery bypass grafting were included in the study. The patients were divided into four groups according to hemoglobin A1c levels as follows: Group 1 including non-diabetic controls (n=11); Group 2 including those with a hemoglobin A1c value of <7% (n=10); Group 3 including those with a hemoglobin A1c value of 7 to 10% (n=11); and Group 4 including those with a hemoglobin A1c value of ≥10% (n=8). Cerebral monitoring was performed with near-infrared spectroscopy and transcranial Doppler. Measurement periods were defined as follows: Before anesthesia induction (period 1), 10 min after anesthesia induction (period 2), during cannulation (period 3), 10 min after cardiopulmonary bypass (period 4), at 32°C temperature during cardiopulmonary bypass (period 5), at 36°C temperature during cardiopulmonary bypass (period 6), and at the end of the operation (period 7). There was a significant difference in the near-infrared spectroscopy values in the cannulation period for both right (p<0.001) and left (p=0.002) sides and the mean transcranial Doppler flow velocity (p=0.002) in Group 4, compared to Group 1. The heart rate was found to be significantly lower in Group 4 in the cannulation period. The near-infrared spectroscopy values and transcranial Doppler blood flow velocity decreased in Group 4 in all measurement periods. The results of our study show that, in patients with severe diabetes undergoing open heart surgery, heart rate decreases in the cannulation period due to possible autonomic neuropathy, and cerebral blood flow and oxygenation decrease. For these patients, particularly in the cannulation period, perfusion of both cerebral and other organs should be closely monitored and necessary interventions should be performed.

An update on the cecectomy technique in roosters anesthetized with isoflurane used in subsequent amino acid digestibility experiments.

This work aims to study an alternative technique of cecectomy in roosters using inhalation anesthesia for subsequent use in digestibility experiments. A total of 30 adult chickens of Leghorn breed were used with an average age of 27 wk. The birds were preoxygenated, and the anesthetic induction was performed using isoflurane diluted in oxygen. After proper muscle relaxation, endotracheal intubation was performed using a Murphy catheter and kept in anesthesia under mechanical ventilation with a constant monitoring of electrocardiography variables, heart rate, oxyhemoglobin saturation, and body temperature during the surgical procedure. An incision of approximately 3cm was made between keel and cloaca in order to expose and extirpate the cecum followed by a simple ligature. The opening of the peritoneal cavity was closed in 2 ways: Sultan suture technique was used for closing the abdominal wall and modified Cushing intradermic continuous points for closing the skin. The time for anesthesia induction and preoperational period noted to be 10 ± 2 min. Surgical procedures completed in 7 ± 1.5 min. No intraoperatively and postoperatively harm observed in animals. Water was immediately provided after the birds returned to cages and feed offered after 24h of surgery. In remaining birds, no abnormalities were observed during and after the experimental period (3 mo). The present study describes a promising update on cecectomy technique regarding anesthesia induction and surgical procedures in roosters using potential drugs and safer surgical materials without any trans- and postoperative complications.

Sevoflurane increases locomotion activity in mice.

Clinical observations show emergence of agitation and hyperactivity during the anesthesia induction and/or recovery period post-anesthesia. However, an animal model to illustrate this clinical phenomenon has not yet been established. We therefore set out to investigate whether sevoflurane, a commonly used anesthetic, could alter locomotion in mice during the anesthesia induction and recovery period post-anesthesia. The activity of the mice was recorded 5 minutes before, during (for 30 minutes), and 40 minutes after the administration of the anesthetic sevoflurane [1-, 1.5- and 2-fold minimum alveolar concentration] at 370 C. The total walking distance and velocity of movement were measured and quantified as the indexes of locomotion. We found that the anesthetic sevoflurane increased the locomotion of the mice during the induction period of the anesthesia. During the recovery phase after anesthesia, the mice exhibited increased locomotion for a short period of time (about 5 minutes) and then displayed a sharp decrease in mobility for up to 60 minutes following the end of anesthesia administration. The anesthetic sevoflurane did not significantly alter the food intake and body weight of the mice. Furthermore, we found that Alzheimer’s disease transgenic mice exhibited a greater degree of sevoflurane-induced hyperactivity than the wild-type mice did. Our results showed that inhalation of the anesthetic sevoflurane induced an acute hyperactivity in mice, particularly among Alzheimer’s disease transgenic mice. These findings from the pilot studies have established an animal model to promote further studies into postoperative emergence agitation, hyperactivity and the underlying mechanisms into these conditions.

Application via mechanical dropper alleviates sufentanil-induced cough: a prospective, randomized, single-blinded trial

BackgroundIt was reported that prolonging the injection time or diluting administration can reduce the incidence of opioid-induced cough. However, the incidence of sufentanil-induced cough (SIC) via a standardized infusion rate is unclear. A mechanical dropper is an infusion filtering device commonly used for intravenous degassing; it can also be used to administer special drugs due to its temporary storage and dilution effect. This study assesses the effectiveness of administration via mechanical dropper on SIC.MethodsTwo hundred patients undergoing general anesthesia were enrolled. Patients received sufentanil at a strength of 0.3 μg·kg− 1 either via T-connector (group C) or by mechanical dropper (group M) at 1 ml·s− 1. Cough severity was graded as none (0), mild (1–2), moderate (3–5), or severe (> 5), and the incidence of SIC was evaluated for 5 min after the start of sufentanil injection. Other adverse reactions such as hypotension, hypertension, bradycardia, tachycardia, hypoxemia, vomiting, and aspiration during the induction period of general anesthesia were also observed. The primary outcome was the incidence of SIC. The secondary outcomes were the severity of SIC and other adverse reactions.ResultsThe incidence of SIC in group M was significantly lower than that in group C (2% versus 21%, P = 0.000), and the prevalence of moderately severe coughing was also statistically different (none in group M versus 11% in group C, P = 0.001). However, there were no statistical differences in the incidence of other adverse reactions between two groups (P > 0.05).ConclusionSufentanil application via mechanical dropper can significantly alleviate the occurrence of SIC during the induction phase of total intravenous general anesthesia. This method is simple, safe, and reliable, and has wide prospective application for clinical use.Trial registrationChinese Clinical Trial Register, ChiCTR-IOR-17011561. Registered on 3 June 2017.

Anesthesia Induction’s Effect on Pediatric Surgery under Parental Accompany: A Comprehensive Meta-Analysis of Randomized Controlled Trials

Objective: To evaluate the effect of anesthesia induction under parental company for children receiving general anesthesia. Methods: The RCT results were collected on children’s preoperative anxiety, anesthesia coordination, anesthesia and recovery agitation, postoperative pain and parental preoperative anxiety intervention with or without parental accompany using RevMan 5.3 software based on Chinese and English database. We searched Cochrane Library, Pubmed, Medline, EMbase, Sciencedirect, SpringerLink, China Biomedical, CNKI, Wanfang, Weipu and other databases, and included 15 articles (5 Chinese, 10 English) with 1390 samples size, containing 700 cases of control group and 690 cases of testing group. Results: Our results showed that parents’ and children’s anxiety level, the incidence of restlessness during anesthesia induction and wake-up period were reduced, while the anesthesia coordination was enhanced and the pain of children after wake-up was alleviated under parental accompany. Conclusion: The risk and cost-free intervention of parental accompany could be recommended as appropriate in hospitals for its contribution to children’s surgery effect.

Characterization of cardiovascular depression effect for propofol during anesthesia induction period on morbidly obese patients

This study aims to determine the pharmacodynamics (PD) effect (measured by cardiovascular depression) of propofol during anesthesia induction period on morbidly obese (MO) patients. Four hemodynamics indexes [i.e., three indexes about blood pressure and cardiac output (CO)] representing cardiovascular function were measured.Pharmacokinetic/pharmacodynamic (PK/PD) modeling was performed by population analysis to obtain PD parameters. Two propofol dosing scalars, namely, dosing based on total body weight (TBW) or lean body weight (LBW), were used for MO subjects. The PD data were well described by a PK/PD model. Blood pressure and CO were rapidly decreased within one minute after intravenous injection of propofol (2 mg/kg). TBW group showed significantly lower blood pressure and CO values at and 1 min after propofol administration compared with the control group, whereas the control and LBW groups had similar PD profiles. In addition, the propofol EC50 value was significantly decreased in MO patients, whereas all other PD parameters were similar between control and MO subjects. This change indicated that propofol potency and/or sensitivity was increased in MO subjects. For MO patients, dosing of propofol based on LBW rather than TBW would be a safer choice due to a less cardiovascular depression effect.

Relationship between cerebral oxygen saturation and hemodynamics under different end-tidal carbon dioxide partial pressure in children with ventricular septal defect

Objective To study the relationship between regional cerebral tissue oxygen saturation (rScO2) and hemodynamic parameters under different end-tidal carbon dioxide partial pressure (PetCO2) levels during anesthesia induction period in children undergoing ventricular septal defect(VSD) repair. Methods A total of 25 patients aged from 2 to 37 months (median 6 months) were enrolled, who received selective VSD repair at Beijing Anzhen Hospital from April to May 2017.After admission, anesthesia induction and intubation, invasive radial artery pressure were established routinely and hemodynamic device-MostCare was used, Fore-Sight was used to monitor rScO2 of the right frontal brain.By means of adjusting mechanical ventilation parameter, PetCO2 was maintained at 30 (T1), 35 (T2), 40 (T2), 45 (T3) mmHg(1 mmHg=0.133 kPa) in sequence.Pulse oxygen saturation (SpO2), heart rate (HR), systolic pressure (SysP), difference between dicrotic pressure(DicP) and diastolic pressure(DiaP) (Pdic-a), stroke volume index (SVI), cardiac index (CI), systemic vascular resistance index (SVRI), and pulse pressure variation (PPV) were recorded at T1, T2, T3 and T4. Results (1) Comparison among groups: rScO2 at T4, T3, T2 and T1 were(80.5±4.0)%, (78.2±4.6)%, (74.4±5.7)%, (70.8±6.5)%, respectively, rScO2 at T2, T3 and T4 were higher than that at T1, and the differences were statistically significant (all P 0.05). Conclusions During anesthesia induction in ventricular septal defect children, rScO2 increases significantly with the increase in PetCO2.When PetCO2 is at 30 and 35 mmHg, rScO2 is mainly affected by hemodynamics.When PetCO2 is at 40 and 45 mmHg, rScO2 is mainly affected by PetCO2, but less affected by hemodynamics. Key words: Congenital heart disease; Cerebral oxygen saturation; Hemodynamics; End-tidal carbon dioxide

Effects of micro video combined scene simulation games on preoperative anxiety in pediatric patients with congenital heart disease

Objective To explore the effects of micro video combined scene simulation games on preoperative anxiety in pediatric patients with congenital heart disease. Methods All the participants were divided into two groups, with 100 cases in each. Patients who underwent congenital heart disease surgery from January to June 2016 were allocated in the control group, and from July to December 2016, patients who underwent the same surgery were allocated in the observation group. The patients of the control group were given routine perioperative nursing care. The patients of the observation group were given micro video combined scene simulation games. All the patients were evaluated with the questionnaire of modified Yale Perioperative Anxiety Scale (mYPAS) and Induction Compliance Checklist (ICC) for the degree of preoperative anxiety and the degree of cooperation in the indection period. Results The level of perioperative anxiety of the two groups were (28.58±2.98) and (28.94±2.63) , and there was no statistical difference (P>0.05) . The degree of anxiety in preoperative waiting period of the observation group was (30.21±2.78) , which was lower than that of the control group (36.89±3.41) . The degree of anxiety in the anesthetic induction period was (31.46±3.34) , which was remarkably lower than that of the control group (41.45±4.19) . The degree of cooperation in induction period of the patients in the observation group was (2.67±1.45) , which was lower than that of the control group (6.95±1.78) . All the differences were statistically significant (t=15.21, 18.83, 8.62; P<0.001) . Conclusions Micro video combined scene simulation game can effectively reduce the level of preoperative anxiety in children with congenital heart disease and improve the cooperation in the induction period of anesthesia. Key words: Child, preschool; Anxiety; Congenital heart disease; Micro video; Scene simulation game

The effects of hypervolemic infusion on microcirculation perfusion of patients during laparoscopic colorectal surgery.

The aim of this study is to assess the effects of hypervolemic infusion with different solutions on microcirculation perfusion during laparoscopic colorectal surgery.Thirty-six patients were randomly divided into Ringer lactate solution [RL] group, succinylated gelatin injection [Gel] group, and hypertonic saline hydroxyethyl starch 40 injection [HS] group. Hypervolemic infusion was performed during the induction period of general anesthesia. Arterial blood-gas parameters, noninvasive hemodynamics, gastric tonometry values, and central venous pressure (CVP) were compared at baseline (T1); the end of hypervolemic infusion (T2); 5 min (T3), 15 min (T4), 30 min (T5), and 60 min (T6) during pneumoperitoneum; 5 min (T7), 15 min (T8), and 25 min (T9) after pneumoperitoneum. Patients were also grouped by age for further comparisons.The hematocrit levels of all groups after T2 decreased. The gastric mucosal-arterial carbon dioxide partial pressure (Pg-aCO2) started to decrease after T2 and rebounded after T5. There was no difference in the gastric mucosal perfusion when compared between 3 groups. The blood Na of HS group increased significantly after T2, then gradually restored and returned to baseline by T8. The plasma bicarbonate (HCO3) levels of RL and Gel groups elevated from T2 to T7, after which they started to decrease, but this phenomenon was not significant in HS group. In both RL and Gel groups, blood pressure has a significant fluctuation in elder patients.Hypervolemic infusion of these solutions during the induction of anesthesia can improve gastric mucosal perfusion. HS can maintain a more stable hemodynamic effect when used with caution in patients with preoperative hypernatremia.

Comparison of the effects of different doses of oxycodone on endotracheal intubation during general anesthesia induction period

Objective To compare the clinical effect of different doses of oxycodone on endotracheal intubation during general anesthesia induction period. Methods Ninety-five patients with endotracheal intubation general anesthesia were selected as the research subjects, and the patients were randomly divided into group A, group B and group C. 31 patients in group A received intravenous administration of oxycodone 0.20mg/kg, 32 patients in group B received intravenous administration of oxycodone 0.25mg/kg, and 32 patients in group C received intravenous administration of oxycodone 0.30mg/kg.The adrenaline, norepinephrine, dopamine concentration, as well as mean arterial pressure and heart rate at different time points were compared among the three groups. Results The mean arterial pressure and heart rate at T0 time point were decreased to varying extent compared with those at T1 time point(t=23.618, 7.412; 22.928, 9.063; 32.636, 9.422, P=0.000, 0.000; 0.000, 0.000; 0.000, 0.000). The heart rate, mean arterial pressure at T2, T3 and T4 time points in group A were increased compared with T0 time point(t=13.834, 6.506, 7.015; 17.604, 14.796, 16.323, P=0.000, 0.000, 0.000; 0.000, 0.000, 0.000). The adrenaline, norepinephrine and dopamine at T2, T3 and T4 time points in group A were increased compared with T0 time point(t=121.662, 64.533, 15.687; 31.498, 16.933, 9.286; 39.712, 116.049, 147.102, P=0.000, 0.000, 0.000; 0.000, 0.000, 0.000; 0.000, 0.000, 0.000). The heart rate, mean arterial pressure, adrenaline, norepinephrine and dopamine at T2, T3 and T4 time points in group B and group C were decreased significantly compared with those in group A(t=19.586, 31.972, 16.844, 27.087; 14.046, 14.822, 15.377, 23.826; 7.756, 14.396, 13.268, 23.342, 100.573, 104.010, 37.612, 38.892, 107.377, 117.969; 56.135, 56.757, 24.223, 25.300, 95.057, 82.088; 22.878, 25.731, 5.532, 5.934, 134.763, 83.628, P=0.000, 0.000, 0.000, 0.000, 0.000, 0.000; 0.000, 0.000, 0.000, 0.000, 0.000, 0.000; 0.000, 0.000, 0.000, 0.000, 0.000, 0.000; 0.000, 0.000, 0.000, 0.000; 0.000, 0.000, 0.000, 0.000; 0.000, 0.000, 0.000, 0.000), and the differences were statistically significant(all P<0.05). Conclusion During the induction of general anesthesia, the appropriate dose of oxycodone in patients with endotracheal intubation was 0.25mg/kg, which could effectively maintain the hemodynamic stability, such as mean arterial pressure, and could reduce the stress response. Key words: Anesthesia, intratracheal; Dose-response relationship, drug; Oxycodone

Effect of external abdominal aorta compression on circulation during anesthesia induction in elderly patients

To investigate the effect of external abdominal aorta compression on circulation during anesthetic induction in elderly patients. A prospective randomized controlled trial was conducted. Patients with age of 60-75 years old, requiring a general anesthesia for non-abdominal surgery, and with II-III class of American Society of Anesthesiologists (ASA) physical status classification, and admitted to General Hospital of Chinese People's Armed Police Forces from January to April in 2017 were enrolled. They were divided into abdominal aorta pressure group and control group according to random number method, with 20 patients in each group. In both groups, anesthesia was induced with midazolam, propofol, fentanyl and cisatracurium, and was maintained with propofol, remifentanil and cisatracurium. After successful intubation, the anesthesia machine was changed into mechanical ventilation. The patients in abdominal aorta pressure group were given abdominal aorta pressure 1 minute after induction of general anesthesia with midazolam till 5 minutes after intubation. The mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO2) were observed before anesthesia induction, immediately after anesthesia induction, immediately after intubation, 5 minutes and 10 minutes after intubation, respectively. The incidence of hypotension or bradycardia, and usage of ephedrine or atropine were recorded. There were no significant differences in MAP [mmHg (1 mmHg = 0.133 kPa): 83.6±4.7 vs. 82.9±4.7], HR (bpm: 67.3±5.9 vs. 65.9±5.7) and SpO2 (0.962±0.007 vs. 0.960±0.009) before anesthesia induction between abdominal aorta pressure group and control group (all P > 0.05). Immediately after anesthesia induction, the MAP and HR in control group were significantly decreased as compared with those before anesthesia induction [MAP (mmHg): 70.0±8.7 vs. 82.9±4.7, HR (bpm): 60.7±6.7 vs. 65.9±5.7, both P < 0.05], and they were also significantly lower than those of abdominal aorta pressure group [MAP (mmHg): 83.1±3.9, HR (bpm): 66.8±4.9, both P < 0.05]. Immediately after intubation, the MAP and HR in control group were significantly increased as compared with those immediately after anesthesia induction [MAP (mmHg): 78.9±7.9 vs. 70.0±8.7, HR (bpm): 67.3±2.7 vs. 60.7±6.7, both P < 0.05], but the changes in MAP and HR in abdominal aorta pressure group were not obvious. During the anesthesia induction period, there was no statistical difference in SpO2 change between the two groups. During induction of anesthesia, no adverse reaction was found in the abdominal aorta pressure group, but 4 patients with hypotension and 2 patients with bradycardia were found in the control group. Two patients with hypotension were treated with ephedrine, and 2 patients with bradycardia were treated with atropine. Anesthesia induction of elderly patients with abdominal aorta pressure can help maintain hemodynamic stability.

Effects of combined midazolam and propofol in anesthesia induction and recovery of cats undergoing ovariohisterectomy

&lt;p&gt;The objective of this study was to determine the effects of propofol and midazolam on induction of anesthesia in cats undergoing ovariohysterectomy, measured in terms of the quality of tracheal intubation, anesthesia induction, cardiorespiratory effects, and recuperation period. Thirty healthy adult cats were pretreated with acepromazine and morphine. After 30 min, they were divided into three groups: PG (n = 10), in which induction was performed with only intravenous propofol at doses required for intubation; MPG (n = 8), in which animals received intravenous midazolam (0.3 mg kg-1) administered over 30 s, followed by administration of propofol as in PG; and PMG (n = 9), in which propofol was first administered at a rate of 4 mg kg-1 min-1, after which midazolam was administered (0.3 mg/kg), followed by re-administration of propofol. In order to perform a blinded study, the PG and PMG received a 0.9% NaCl solution volume similar to the midazolam dose before induction (0.06 mL/kg). Similar to the other groups, the PG and MPG received (0.06 mL kg-1) saline 30 s after administration of propofol. In order to mimic the administration of midazolam, the saline solution was administered for 30s. The PG received 11.0 ± 1.38 mg kg-1 propofol, a greater dose than that administered to the PMG (p &amp;lt; 0.001) and MPG (p &amp;lt; 0.01), which received 7.9 ± 1.92 and 9.1 ± 2.20 mg kg-1, respectively. There were no differences in the intubation scores between groups. Previous use of midazolam did not affect agitation or excitement in cats; both sequences of propofol-midazolam administration are feasible, but the propofol-midazolam sequence was superior due to the lower propofol dose.&lt;/p&gt;

Effects of combined midazolam and propofol in anesthesia induction and recovery of cats undergoing ovariohisterectomy

The objective of this study was to determine the effects of propofol and midazolam on induction of anesthesia in cats undergoing ovariohysterectomy, measured in terms of the quality of tracheal intubation, anesthesia induction, cardiorespiratory effects, and recuperation period. Thirty healthy adult cats were pretreated with acepromazine and morphine. After 30 min, they were divided into three groups: PG (n = 10), in which induction was performed with only intravenous propofol at doses required for intubation; MPG (n = 8), in which animals received intravenous midazolam (0.3 mg kg-1) administered over 30 s, followed by administration of propofol as in PG; and PMG (n = 9), in which propofol was first administered at a rate of 4 mg kg-1 min-1, after which midazolam was administered (0.3 mg/kg), followed by re-administration of propofol. In order to perform a blinded study, the PG and PMG received a 0.9% NaCl solution volume similar to the midazolam dose before induction (0.06 mL/kg). Similar to the other groups, the PG and MPG received (0.06 mL kg-1) saline 30 s after administration of propofol. In order to mimic the administration of midazolam, the saline solution was administered for 30s. The PG received 11.0 ± 1.38 mg kg-1 propofol, a greater dose than that administered to the PMG (p &lt; 0.001) and MPG (p &lt; 0.01), which received 7.9 ± 1.92 and 9.1 ± 2.20 mg kg-1, respectively. There were no differences in the intubation scores between groups. Previous use of midazolam did not affect agitation or excitement in cats; both sequences of propofol-midazolam administration are feasible, but the propofol-midazolam sequence was superior due to the lower propofol dose.

The role of pulse oximetry plethysmographic waveform monitoring as a marker of restoration of spontaneous circulation:a pilot study

To investigate the feasibility of using pulse oximetry plethysmographic waveform (POP) to identify the restoration of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). An observational research was conducted. A porcine model of ventricular fibrillation (VF) arrest was reproduced. After 3 minutes of untreated VF, animals received CPR according to the latest CPR guidelines, providing chest compressions to a depth of 5 cm with a rate of 105 compressions per minute and instantaneous mechanical ventilation. After 2 minutes of CPR, animals were defibrillated with 100 J biphasic, followed by continuous chest compressions. Data of hemodynamic parameters, partial pressure of end-tidal carbon dioxide (PETCO₂) and POP were collected. The change in POP was observed, and the characteristics of changes of the waves were recorded during the peri-CPR period using the time and frequency domain methods. VF was successfully induced in 6 pigs, except 1 death in anesthesia induction period. (1) After VF, invasive blood pressure waveform and POP of the animals disappeared. PETCO₂was (18.83 ± 2.71) mmHg (1 mmHg=0.133 kPa), and diastolic arterial pressure was (23.83 ± 5.49) mmHg in compression stage. Animals attained ROSC within 1 minute after defibrillation, with PETCO₂[(51.83 ± 9.35) mmHg] and diastolic arterial pressure [(100.67 ± 10.97) mmHg] elevated significantly compared with that of compression stage (t1 = 8.737, t2 = 25.860, both P = 0.000), with appearance of arterial blood pressure waveform.(2) Characteristic changes in POP were found in all experimental animals. During the stages of induced VF, compression, ROSC, and compression termination, POP showed characteristic waveform changes. POP showed disappearance of waveform, regular compression wave, fluctuation hybrid and stable pulse wave in time domain method; while in the frequency domain method waveform disappearance, single peak of compression, double or fusion peak and single peak of pulse were observed. Analysis of POP using time and frequency domain methods could not only quickly detect cardiac arrest, but also show a role as a feasible, non-invasive marker of ROSC during CPR.