Effect of lidocaine on intraoperative blood pressure variability in patients undergoing major vascular surgery.

BACKGROUND: Dynamic fluctuations of arterial blood pressure known as blood pressure variability (BPV) may have short and long-term undesirable consequences. During surgical procedures blood pressure is usually measured in equal intervals allowing to assess its intraoperative variability, which significance for peri and post-operative period is still under debate. Lidocaine has positive cardiovascular effects, which may go beyond its antiarrhythmic activity. The aim of the study was to verify whether the use of intravenous lidocaine may affect intraoperative BPV in patients undergoing major vascular procedures. METHODS: We performed a post-hoc analysis of the data collected during the previous randomized clinical trial by Gajniak et al. In the original study patients undergoing elective abdominal aorta and/or iliac arteries open surgery were randomized into two groups to receive intravenous infusion of 1% lidocaine or placebo at the same infusion rate based on ideal body weight, in concomitance with general anesthesia. We analyzed systolic (SBP), diastolic (DBP) and mean arterial blood (MAP) pressure recorded in 5-minute intervals (from the first measurement before induction of general anaesthesia until the last after emergence from anaesthesia). Blood pressure variability was then calculated for SBP and MAP, and expressed as: standard deviation (SD), coefficient of variation (CV), average real variability (ARV) and coefficient of hemodynamic stability (C10%), and compared between both groups. RESULTS: All calculated indexes were comparable between groups. In the lidocaine and placebo groups systolic blood pressure SD, CV, AVR and C10% were 20.17 vs. 19.28, 16.40 vs. 15.64, 14.74 vs. 14.08 and 0.45 vs. 0.45 respectively. No differences were observed regarding type of surgery, operating and anaesthetic time, administration of vasoactive agents and intravenous fluids, including blood products. CONCLUSION: In high-risk vascular surgery performed under general anesthesia, lidocaine infusion had no effect on arterial blood pressure variability. TRIAL REGISTRATION: ClinicalTrials.gov; NCT04691726 post-hoc analysis; date of registration 31/12/2020.

Efficacy of Lidocaine Infusion in High-Risk Vascular Surgery-A Randomized, Double-Blind, Placebo-Controlled Single-Center Clinical Trial.

BACKGROUND: In perioperative pain control, adjuvants such as lidocaine can reduce opioid consumption in a specific type of surgery. The aim of this single-center prospective double-blinded randomized controlled trial was to determine opioid consumption in the perioperative period in patients receiving continuous lidocaine infusion. METHODS: Patients undergoing elective abdominal aorta and/or iliac arteries open surgery were randomized into two groups to receive 1% lidocaine or placebo at the same infusion rate based on ideal body weight (bolus of 0.15 mL/kg during the induction of anesthesia followed by continuous infusion of 0.2 mL/kg/h during surgery; postoperatively 0.1 mL/kg/h for 24 h) additionally to standard opioid analgesia. RESULTS: Total opioid consumption within 24 h after surgery was 89.2 mg (95%CI 80.9-97.4) in the lidocaine and 113.1 mg (95%CI 102.5-123.6) in the placebo group (p = 0.0007). Similar findings were observed in opioid consumption intraoperatively (26.7 mg (95%CI 22.2-31.3) vs. 35.1 mg (95%CI 29.1-41.2), respectively, p = 0.029) and six hours postoperatively (47.5 mg (IQR 37.5-59.5) vs. 60 mg (IQR 44-83), respectively, p = 0.01). CONCLUSIONS: In high-risk vascular surgery, lidocaine infusion as an adjunct to standard perioperative analgesia is effective. It may decrease opioid consumption by more than 20% during the first 24 h after surgery, with no serious adverse effects noted during the study period.

The Role of Deep Hypothermia in Cardiac Surgery.

Hypothermia is defined as a decrease in body core temperature to below 35 °C. In cardiac surgery, four stages of hypothermia are distinguished: mild, moderate, deep, and profound. The organ protection offered by deep hypothermia (DH) enables safe circulatory arrest as a prerequisite to carrying out cardiac surgical intervention. In adult cardiac surgery, DH is mainly used in aortic arch surgery, surgical treatment of pulmonary embolism, and acute type-A aortic dissection interventions. In surgery treating congenital defects, DH is used to assist aortic arch reconstructions, hypoplastic left heart syndrome interventions, and for multi-stage treatment of infants with a single heart ventricle during the neonatal period. However, it should be noted that a safe duration of circulatory arrest in DH for the central nervous system is 30 to 40 min at most and should not be exceeded to prevent severe neurological adverse events. Personalized therapy for the patient and adequate blood temperature monitoring, glycemia, hematocrit, pH, and cerebral oxygenation is a prerequisite and indispensable part of DH.

The efficiency of continuous renal replacement therapy for rewarming of patients in accidental hypothermia--An experimental study.

Severe accidental hypothermia carries high mortality and morbidity and is often treated with invasive extracorporeal methods. Continuous veno-venous hemodiafiltration (CVVHDF) is widely available in intensive care units. We sought to provide theoretical basis for CVVHDF use in rewarming of hypothermic patients. CVVHDF system was used in the laboratory setting. Heat balance and transferred heat units were evaluated for the system without using blood. We used 5L of crystalloid solution at the temperature of approximately 25°C, placed in a thermally insulated tank (representing the "central compartment" of a hypothermic patient). Time of warming the central compartment from 24.9 to 30.0°C was assessed with different flow combinations: "blood" (central compartment fluid) 50 or 100 or 150 mL/min, dialysate solution 100 or 1500 mL/h, and substitution fluid 0 or 500 mL/h. The total circulation time was 1535 minutes. There were no differences between heat gain values on the filter depending on blood flow (P = .53) or dialysate flow (P = .2). The mean heating time for "blood" flow rates 50, 100, and 150 mL/min was 113.7 minutes (95% CI, 104.9-122.6 minutes), 83.3 minutes (95% CI, 76.2-90.3 minutes), and 74.7 minutes (95% CI, 62.6-86.9 minutes), respectively (P < .01). The respective median rewarming rate for different "blood" flows was 3.6°C/h (IQR, 3.0-4.2°C/h), 4.8 (IQR, 4.2-5.4°C/h), and 5.4 (IQR, 4.8-6.0°C/h), respectively (P < .01). The dialysate flow did not affect the warming rate. Based on our experimental model, CVVHDF may be used for extracorporeal rewarming, with the rewarming rates increasing achieved with higher blood flow rates.

Enhanced recovery after cardiac surgery.

The concept of early recovery after surgery (ERAS) consists of bundle interventions during the pre-, intra- and postoperative periods and team work. The ERAS, which is a multimodal strategy, enables one to limit the neurohumoral response to the surgery, maintain homeostasis, reduce the risk of complications, shorten the hospital stay, accelerate the return to everyday functioning, improve the patient's satisfaction, achieve a satisfactory quality of life and finally reduce the treatment costs and eliminate any redundant and ineffective practices. Almost every patient can be classified for the ERAS strategy except for patients undergoing urgent and emergency surgery. The necessity to give up ERAS can result from poor organisation and management. Moreover, the procedure itself can be the cause of the lack of adherence to the planned standard. It is necessary to use protocols and checklists. While fulfilling this doctrine, the anaesthesiologist becomes a perioperative specialist.

Inter-arm differences in blood pressure among subjects with disseminated atherosclerosis scheduled for vascular surgery.

BACKGROUND: The measurement of blood pressure (BP) is routinely performed in perioperative care. The reliability of results is essential for the implementation of treatment ensuring haemodynamic stability. The aim of the present study was to assess the prevalence and basic determinants of inter-arm BP differences among patients with advanced peripheral atherosclerosis undergoing vascular surgical procedures of the lower limbs. METHODS: The prospective study was carried out in patients scheduled for elective lower limb vascular surgery. One-time non-invasive BP measurements were performed sequentially on the brachial arteries of both upper extremities before the induction of anaesthesia, maintaining the shortest possible interval between measurements. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were recorded. RESULTS: The results of 173 patients (including 123 men aged 67 ± 8 years) were analysed. In 16 (9.3%) patients, an inter-arm difference in BP was already observed during the preoperative examination. SBP and DBP was higher in the right limb in 86 (49.7%) an 80 (46.3%) patients, respectively. Moreover, the medians of inter-arm differences in SBP, DBP and MAP were 9 (IQR 4-17), 5 (IQR 3-10) and 7 mm Hg (IQR 3-12), respectively. An evaluation of the determinants of BP differences related to the presence of additional diseases demonstrated that patients with arterial hypertension were characterised by higher SBP and MAP disproportions (P = 0.04 and P = 0.01). CONCLUSIONS: In the population of patients with disseminated atherosclerosis, the inter-arm differences in BP substantially exceed the measurement error limits and are likely to be associated with arterial hypertension. If in doubt about BP disproportions, intraoperative monitoring of BP should be recommended using an invasive method on the limb presenting higher non-invasively measured values.