A protocol based on hypotension probability indicator vs. standard care to prevent intraoperative hypotension during supratentorial brain surgery: a prospective randomized pilot trial.

BACKGROUND: To test the hypothesis that Hypotension probability indicator (HPI) driven hemodynamic protocol use may decrease the exposition to hypotension (mean arterial pressure below 65 mmHg) during supratentorial intracranial procedures. METHODS: Patients undergoing supratentorial tumor resection under general anesthesia (ASA 1-3) were included into this randomized single center-controlled pilot trial. Patients in the control group (COV, N.=20) were managed based on the institutional standard to avoid hypotension. Patients in the intervention (INT, N.=20) group were managed using a protocol triggered by the HPI above 85 based on the stroke volume variation, dynamic elastance, and cardiac index parameters. The number of patients experiencing hypotension (mean arterial pressure below 65 mmHg) during the whole procedure and anesthesia maintenance phase was the primary outcome variable. The number of hypotensive periods, time spent in hypotension, and hypotension dose served as secondary outcome variables. Other clinically relevant parameters and postsurgical outcomes were screened. RESULTS: The number of patients who never experienced hypotension was significantly lower in the INT group during the anesthesia maintenance phase (10 (50%) vs. 16 (80%); P=0.049). In several other hemodynamic outcomes, a distinct numerical, but statistically non-significant trend towards lower hypotension exposition was observed. There were no significant differences in clinically relevant parameters. CONCLUSIONS: In this pilot trial, the HPI-based protocol decreased the incidence of hypotension during the anesthesia maintenance but non-significant trends among secondary outcomes were also documented. Larger trials are needed to confirm our findings.

Clinical physiology aspects of chloremia in fluid therapy: a systematic review.

BACKGROUND: This systematic review discusses a clinical physiology aspect of chloride in fluid therapy. Crystalloid solutions are one of the most widely used remedies. While generally used in medicine for almost 190 years, studies focused largely on their safety have only been published since the new millennium. The most widely used solution, normal saline, is most often referred to in this context. Its excessive administration results in hyperchloremic metabolic acidosis with other consequences, including higher mortality rates. METHODS: Original papers and review articles eligible for developing the present paper were identified by searching online in the electronic MEDLINE database. The keywords searched for included hyperchloremia, hypochloremia, and compound words containing the word "chloride," infusion therapy, metabolic acidosis, renal failure, and review. RESULTS: A total of 21,758 papers published before 31 May 2020 were identified; of this number, 630 duplicates were removed from the list. Upon excluding articles based on their title or abstract, 1850 papers were screened, of which 63 full-text articles were assessed. CONCLUSIONS: According to the latest medical concepts, dyschloremia (both hyperchloremia and hypochloremia) represents a factor indisputably having a negative effect on selected variables of clinical outcome. As infusion therapy can significantly impact chloride homeostasis of the body, the choice of infusion solutions should always take into account the potentially adverse impact of chloride content on chloremia and organ function.

Endothelial glycocalyx in acute care surgery - what anaesthesiologists need to know for clinical practice.

The endothelial glycocalyx (EG) is the thin sugar-based lining on the apical surface of endothelial cells. It has been linked to the physiological functioning of the microcirculation and has been found to be damaged in critical illness and after acute care surgery. This review aims to describe the role of EG in severely injured patients undergoing surgery, discuss specific situations (e.G. major trauma, hemorrhagic shock, trauma induced coagulopathy) as well as specific interventions commonly applied in these patients (e.g. fluid therapy, transfusion) and specific drugs related to perioperative medicine with regard to their impact on EG.EG in acute care surgery is exposed to damage due to tissue trauma, inflammation, oxidative stress and inadequate fluid therapy. Even though some interventions (transfusion of plasma, human serum albumin, hydrocortisone, sevoflurane) are described as potentially EG protective there is still no specific treatment for EG protection and recovery in clinical medicine.The most important principle to be adopted in routine clinical practice at present is to acknowledge the fragile structure of the EG and avoid further damage which is potentially related to worsened clinical outcome.

Propofol versus sevoflurane anaesthesia: effect on cognitive decline and event-related potentials.

Postoperative cognitive dysfunction (POCD) is diagnosed in up to 30% patients after anaesthesia. The causative role of anaesthetic toxicity remains unclear. Using clinical tests, no clear-cut differences have been observed between anaesthetics so far. The aim of this trial was to compare the incidence of POCD diagnosed by a battery of neuropsychologic tests after propofol and sevoflurane anaesthesia. Secondary goal was to examine possible relationship between POCD positivity and changes in auditory event-related potentials (ERPs). Sixty patients undergoing lumbar discectomy were prospectively randomized to receive depth-controlled sevoflurane (SEVO) or propofol (PROP) based anaesthesia. The neuropsychological examination and auditory event-related potentials (N1, P3a and P3b components) recording was performed preoperatively and on days 1, 6 and 42 after surgery. POCD was defined as a decline of more than one standard deviation in three or more tests. In 43 patients (20 in PROP and 23 in SEVO group) all selected tests were performed and used for the evaluation. POCD was present in 48%/60%, 18%/20% and 17%/11% (SEVO/PROP) of patients on days 1, 6 and 42 after surgery, with no significant intergroup difference. Among neuropsychologic tests, the most significant decline was observed in Semantic Verbal Fluency and Letter-Number Sequencing Test scores, congruently in both groups on days 1 and 6, with full recovery on the last control. Transient deteriorations in other tests were observed as well. No association of POCD positivity and ERPs changes was found, although long-term modifications of P3a and P3b components were observed, mainly in SEVO group. In our study, sevoflurane and propofol anaesthesia was associated with the similar incidence of POCD. Cognitive decline, mainly affecting executive functions, was temporary in most of the patients. Prolonged ERPs alterations after the anaesthesia seem not to have any relationship with the impairment registered by the neuropsychological examination and may represent subclinical changes.

Neuraxial anesthesia is less harmful to the endothelial glycocalyx during elective joint surgery compared to general anesthesia.

BACKGROUND: Damage of the endothelial glycocalyx (EG) has been described during surgery, but the effect of different anesthesia techniques remains unknown. Perfused boundary region (PBR) evaluated by side-stream dark field (SDF) imaging of the sublingual microcirculation enables in vivo EG assessment. PBR values are inversely related to the EG thickness. OBJECTIVE: The aim of the observational study was to evaluate the changes of PBR in patients undergoing elective joint surgery under general (GA) vs. neuraxial anesthesia (NA). Our hypothesis was that PBR will be lower in patients in NA. METHODS: Sixty consecutive patients (ASA 1-3) undergoing elective total knee or hip replacement under GA or NA were included in this prospective observational cohort study. PBR in the sublingual microcirculation was recorded in each patient using SDF at two time points - before surgery and 2 hours after surgery. RESULTS: Before surgery, there was no significant difference in baseline PBR between groups (NA: 1.95 µm (±0.24); GA: 2.02 µm (±0.26); p = 0.098). Postoperatively (2 hours after surgery) PBR was significantly increased in both groups with respect to baseline values (NA: 2.09 µm (±0.19), GA: 2.20 µm (±0.25); p < 0.001). In the GA group, postoperative PBR values were significantly higher than in the NA group (p = 0.006). CONCLUSION: Joint surgery led to significant increases of PBR. Patients in the GA group had significantly higher PBR values 2 hours after surgery compared to NA group. This might implicate that NA is associated with less EG damage then GA in elective hip/knee surgery.

Impact of Intravenous Fluid Challenge Infusion Time on Macrocirculation and Endothelial Glycocalyx in Surgical and Critically Ill Patients.

(i) Purpose. The fluid challenge (FC) is a well-established test of preload reserve. Only limited data exist in regard to the FC efficacy based on infusion time. Slow administration may be associated with lack of effect based on fluid redistribution and external conditions changes. On the contrary, fast administration may lead to brisk fluid overload and damage to the endothelium and endothelial glycocalyx (EG). The aim of this trial was to compare the FC infusion time on its hemodynamic effects and EG. (ii) Methods. Prospective randomized single-center trial of fast (5-10 minutes) versus slow (20-30 minutes) administration of 500ml balanced crystalloid FC in spinal surgery (cohort OR) and septic shock (cohort SEP) patients. Hemodynamic response was assessed using standard monitoring and blood flow measurements; damage to EG was assessed using the perfused boundary region (PBR) via intravital microscopy monitoring in the sublingual region within relevant time points ranging up to 120 minutes. (iii) Results. Overall, 66 FCs in 50 surgical and 16 septic patients were assessed. Fluid administration was associated with increase of PBR in general (1.9 (1.8-2.1) vs. 2.0 (1.8-2.2); p= 0.008). These changes were transient in OR cohort whereas they were long-lasting in septic fluid responders. The rate of fluid responsiveness after fast versus slow administration was comparable in global population (15 (47%) vs. 17 (50%); p=0.801) as well as in both cohorts. (iv) Conclusions. Fluid challenge administration was associated with increased PBR (and presumable EG volume changes) which normalized within the next 60 minutes in surgical patients but remained impeded in septic fluid responders. The fluid responsiveness rate after fast and slow FC was comparable, but fast administration tended to induce higher, though transient, response in blood pressure.

Cognitive impairment measured by event-related potentials during early and late postoperative period following intravenous or inhalation anaesthesia.

OBJECTIVE: This study investigated modification in cognitive function following inhalation (IA) and total intravenous (TIVA) anaesthesia measured using auditory ERPs (Event Related Potentials). METHODS: Auditory ERPs examination with N1, P3a and P3b component registration was carried out one day before surgery (D-1) and on the first (D+1), sixth (D+6) and 42nd (D+42) days after surgery. Results were compared between two anaesthetic groups. RESULTS: On D+1, N1 latency was increased in the IA group. A significant reduction was observed in amplitude of the P3a component on D+6, which persisted up to D+42 for both IA and TIVA groups. A reduction in the amplitude of P3b on D+1 with normalization by D+6 was found in both groups as well. CONCLUSIONS: Intravenous and inhalation anaesthesia lead to similar changes in cognitive function as determined by ERPs, both during the early and late postoperative periods. It cannot be clearly confirmed whether the observed effects are due to anaesthesia or other unmonitored perioperative factors. SIGNIFICANCE: Post anaesthetic changes represent a subclinical impairment; nevertheless, they represent a potential risk for subsequent development of cognitive difficulties.

Comparison of the accuracy of hemoglobin point of care testing using HemoCue and GEM Premier 3000 with automated hematology analyzer in emergency room.

The laboratory analysis provides accurate, but time consuming hemoglobin level estimation especially in the emergency setting. The reliability of time-sparing point of care devices (POCT) remains uncertain. We tested two POCT devices accuracy (HemoCue®201+ and Gem®Premier™3000) in routine emergency department workflow. Blood samples taken from patients admitted to the emergency department were analyzed for hemoglobin concentration using a laboratory reference Beckman Coulter LH 750 (HBLAB), the HemoCue (HBHC) and the Gem Premier 3000 (HBGEM). Pairwise comparison for each device and HbLAB was performed using correlation and the Bland-Altman methods. The reliability of transfusion decision was assessed using three-zone error grid. A total of 292 measurements were performed in 99 patients. Mean hemoglobin level were 115 ± 33, 110 ± 28 and 111 ± 30 g/l for HbHC, HbGEM and HbLAB respectively. A significant correlation was observed for both devices: HbHC versus HbLAB (r2 = 0.93, p < 0.001) and HBGEM versus HBLAB (r2 = 0.86, p < 0.001). The Bland-Altman method revealed bias of -3.7 g/l (limits of agreement -20.9 to 13.5) for HBHC and HBLAB and 2.5 g/l (-18.6 to 23.5) for HBGEM and HBLAB, which significantly differed between POCT devices (p < 0.001). Using the error grid methodology: 94 or 91 % of values (HbHC and HbGEM) fell in the zone of acceptable difference (A), whereas 0 and 1 % (HbHC and HbGEM) were unacceptable (zone C). The absolute accuracy of tested POCT devices was low though reaching a high level of correlation with laboratory measurement. The results of the Morey´s error grid were unfavorable for both POCT devices.

Fluid management guided by a continuous non-invasive arterial pressure device is associated with decreased postoperative morbidity after total knee and hip replacement.

BACKGROUND: The use of goal directed fluid protocols in intermediate risk patients undergoing hip or knee replacement was studied in few trials using invasive monitoring. For this reason we have implemented two different fluid management protocols, both based on a novel totally non-invasive arterial pressure monitoring device and compared them to the standard (no-protocol) treatment applied before the transition in our academic institution. METHODS: Three treatment groups were compared in this prospective study: the observational (CONTROL, N = 40) group before adoption of fluid protocols and two randomized groups after the transition to protocol fluid management with the use of the continuous non-invasive blood pressure monitoring (CNAP®) device. In the PRESSURE group (N = 40) standard variables were used for restrictive fluid therapy. Goal directed fluid therapy using pulse pressure variation was used in the GDFT arm (N = 40). The influence on the rate of postoperative complications, on the hospital length of stay and other parameters was assessed. RESULTS: Both protocols were associated with decreased fluid administration and maintained hemodynamic stability. Reduced rate of postoperative infection and organ complications (22 (55 %) vs. 33 (83 %) patients; p = 0.016; relative risk 0.67 (0.49-0.91)) was observed in the GDFT group compared to CONTROL. Lower number of patients receiving transfusion (4 (10 %) in GDFT vs. 17 (43 %) in CONTROL; p = 0.005) might contribute to this observation. No significant differences were observed in other end-points. CONCLUSION: In our study, the use of the fluid protocol based on pulse pressure variation assessed using continuous non-invasive arterial pressure measurement seems to be associated with a reduction in postoperative complications and transfusion needs as compared to standard no-protocol treatment. TRIAL REGISTRATION: ACTRN12612001014842.