The Effect of Intravenous Dexamethasone and Dexmedetomidine on Analgesia Duration of Supraclavicular Brachial Plexus Block: A Randomized, Four-Arm, Triple-Blinded, Placebo-Controlled Trial

Intravenous dexamethasone and dexmedetomidine, in conjunction with peripheral nerve blockade, have each been reported to prolong the duration of analgesia. This study tested whether combined use further prolongs analgesia duration after supraclavicular brachial plexus block (BPB) in patients undergoing orthopedic upper extremity surgery. One hundred twenty patients were randomized 1:1:1:1 to Control (saline bolus and midazolam infusion [0.05 mg/kg loading, 20 µg/kg/h thereafter]); DMED (saline bolus and dexmedetomidine infusion [1 μg/kg loading, 0.4 μg/kg/h thereafter]); DEXA (dexamethasone [10 mg] bolus and midazolam infusion); and DMED-DEXA (dexmedetomidine infusion and dexamethasone bolus) groups. The primary outcome was the duration of postoperative analgesia, defined as the time from the end of the BPB to the first dose of analgesia via a patient-controlled device. Median (interquartile range) times to first dose of analgesia in the Control, DMED, DEXA, and DMED-DEXA groups were 8.1 (6.2–11.6), 9.0 (8.1–11.3), 10.7 (8.1–20.5), and 13.2 (11.5–19.1) hours, respectively (p < 0.001). Pairwise comparisons showed significant prolongation of analgesia in the DEXA included groups compared with the non-DEXA included groups (DEXA vs. control, p = 0.045; DEXA vs. DMED, p = 0.045; DMED-DEXA vs. control, p < 0.001; DMED-DEXA vs. DMED, p < 0.001). A mixed effect model showed that dexamethasone was the only significant factor for the prolongation of analgesia (p < 0.001). Intravenous dexamethasone prolonged the analgesia duration of supraclavicular BPB after orthopedic upper extremity surgery. The concurrent use of mild to moderate sedation dose of intravenous dexmedetomidine in addition to intravenous dexamethasone showed no additional benefit to the prolongation of analgesia.

Lung Perfusion Assessment by Bedside Electrical Impedance Tomography in Critically Ill Patients

As a portable, radiation-free imaging modality, electrical impedance tomography (EIT) technology has shown promise in the bedside visual assessment of lung perfusion distribution in critically ill patients. The two main methods of EIT for assessing lung perfusion are the pulsatility and conductivity contrast (saline) bolus method. Increasing attention is being paid to the saline bolus EIT method in the evaluation of regional pulmonary perfusion in clinical practice. This study seeks to provide an overview of experimental and clinical studies with the aim of clarifying the progress made in the use of the saline bolus EIT method. Animal studies revealed that the saline bolus EIT method presented good consistency with single-photon emission CT (SPECT) in the evaluation of lung regional perfusion changes in various pathological conditions. Moreover, the saline bolus EIT method has been applied to assess the lung perfusion in a pulmonary embolism and the effect of positive end-expiratory pressure (PEEP) on regional ventilation/perfusion ratio (V/Q) and acute respiratory distress syndrome (ARDS) in several clinical studies. The implementation of saline boluses, data analyses, precision, and cutoff values varied among different studies, and a consensus must be reached regarding the clinical application of the saline bolus EIT method. Further study is required to validate the impact of the described saline bolus EIT method on decision-making, therapeutic management, and outcomes in critically ill patients.

Fluid therapy in pyloric stenosis – assessment of the implementation of hospital guidelines

Introduction: The preoperative correction of the hypochloremic, hypokalemic metabolic alcalosis in children with infantile hypertrophic pyloric stenosis (IHPS) is essential to optimal outcome. Aim: The main aim of the study was the assessment of the implementation of hospital guidelines for intravenous fluid therapy in children with IHPS. Material and methods: In our Department, at the beginning of 2018 hospital guidelines for intravenous fluid therapy in children were implemented. Two internal audits were performed and surgeons’ compliance with the current recommendations was evaluated. We assessed: the type of fluid transfused, a rate of transfusion and whether saline bolus was given. The study group consisted of 50 patients. Results and discussion: After new guidelines were implemented, appropriate iv fluid was given to 68.7% of children compared to 5.1% before implementation (P = 0.0001). Proper transfusion rate was used in 44.1% of patients before introduction of new guidelines and in 81.2% after that (P = 0.01). Second audit showed that all children had received the recommended iv fluid (P = 0.007) at a good transfusion rate (P = 0.02). In patients who had received the recommended iv fluid, the length of hospital stay after surgery (P = 0.023) and the total length of stay (P = 0.018) were shorter. Conclusions: The new guidelines have raised the level of the whole care for children with pyloric stenosis. The internal audits played an important role in their implementation.

COMPARISON OF END-EXPIRATORY LUNG VOLUME MEASUREMENT BY ELECTRICAL IMPEDANCE TOMOGRAPHY AND NITROGEN WASHOUT METHOD IN PIGS

End-expiratory lung volume (EELV) can be determined using several methods that allow clinically accurate measurements, but it is difficult to apply these methods to the patient's bedside. Electrical impedance tomography (EIT) is offered as another method for measuring EELV. The aim of the study is to compare changes in EELV measured by nitrogen washout method with changes of EELV calculated from the change in end-expiratory lung impedance (EELI) measured by EIT and to determine whether changes in EELV calculated from changes in chest impedance can be used as one of the parameters for EIT data analysis and description. The prospective interventional animal study was performed on ten pigs. The animals received total intravenous anesthesia with muscle relaxation. Mechanical lung ventilation was conducted in the volume-controlled mode. 16-electrode EIT system was used for data acquisition. End-expiratory lung volume was measured by a modified nitrogen wash-in/wash-out technique developed by Olegard et al. The study protocol consisted of the baseline phase, two incremental PEEP steps, two decremental PEEP steps and from normal saline i. v. administration. For each animal, a reference frame (baseline frame) was selected from the initial baseline phase and was used for the reconstruction of EIT images and impedance waveforms. For each breath cycle, tidal variation image was calculated as a difference between the end-inspiratory and the previous end-expiratory EIT image. An equivalent end-expiratory volume change (ΔEELVequiv) was calculated from EELI. The values of ΔEELVequiv were compared with reference EELV data measured by a modified nitrogen wash-in/wash-out technique (ΔEELVmeas). The measured and the estimated changes in EELV were statistically compared and correlation between ΔEELVequiv and ΔEELVmeas was calculated. Statistically significant difference between ΔEELVequiv and ΔEELVmeas was observed only in administration of normal saline bolus. Pearson’s correlation coefficients were 0.29 for increase in PEEP, 0.45 for decrease in PEEP and -0.1 during administration of normal saline bolus. The study showed that during changes in PEEP in the porcine model, there was no linear relationship between ΔEELVequiv and ΔEELVmeas. Although there was no linear relationship between ΔEELVequiv and ΔEELVmeas with changes in PEEP, no statistically significant difference was demonstrated between these two methods, which justifies the use of ΔEELVequiv as a parameter suitable for description and evaluation of EIT data.

Minimizing contrast media dose in CT pulmonary angiography with high-pitch technique

Objectives: To perform CT pulmonary angiography (CTPA) using a minimal amount of iodinated contrast media. Methods: 47 patients (25 females) with mean age 69 years (range 41–82 years) referred for contrast-enhanced chest CT were prospectively included in this Phase IV clinical drug trial. All participants underwent a study specific CTPA in addition to the chest CT. The participants received 80 mg I/kg body weight Iohexol contrast media using a preparatory saline bolus, a dual flow contrast/saline bolus and a saline flush, and a scanner protocol with 80 kVp dual source high-pitch mode. Three readers independently assessed the image quality on the 3-point scale non-diagnostic, adequate or good-excellent image quality. Additionally, the pulmonary arterial contrast opacification was measured. Results: On average, the patients received 16.8 ml Iohexol 350 mg I/mL (range 12–20 ml). Mean patient weight was 71 kg (range 50–85 kg). Identically for all readers, pulmonary embolism (PE) was detected in 1/47 participants. The median number of examinations visually scored concerning pulmonary embolism as good–excellent was 47/47 (range 44–47); adequate 0/47 (0–3) and non-diagnostic 0/47 (range 0–0). The proportion adequate or better examinations was for all readers 47/47, 100% [95% confidence interval 92–100%]. The mean attenuation ± standard deviation in the pulmonary trunk was 325 ± 72 Hounsfield unit (range 165–531 Hounsfield unit). Conclusions: Diagnostic CTPA with 17 ml contrast media is possible in non-obese patients using low kVp, high pitch and carefully designed contrast media administration. Advances in knowledge: By combining several procedures in a CTPA protocol, the contrast media dose can be minimized.