Respiratory Variables Research Articles

Influence of an inspiratory muscle fatigue protocol on older adults on respiratory muscle strength and heart rate variability. A randomized controlled trial

IntroductionInspiratory muscle fatigue has been shown to have effects on the autonomic nervous system and physical condition. This study aimed to evaluate the influence of an inspiratory muscle fatigue protocol on respiratory muscle strength and heart rate variability in older adults.Materials and methodsA randomized controlled clinical trial with double-blinding was carried out involving 24 individuals over 60 years old who demonstrated physical independence in walking and movement. Participants were distributed randomly into three groups: Inspiratory muscle fatigue, activation and control. Measurements of heart rate variability, diaphragmatic ultrasound, and maximum inspiratory pressure were taken at two stages: prior to the intervention (T1) and directly after treatment (T2).ResultsThe inspiratory muscle fatigue group exhibited decrease scores in respiratory and heart rate variability subsequent to undergoing the diaphragmatic fatigue intervention compared to both the activation and control groups (p < 0.05). Conversely, the activation group demonstrated higher values in heart rate variability and respiratory capacity variables following the inspiratory muscle activation training (p < 0.05).ConclusionsFatigue of the inspiratory musculature appears to negatively impact heart rate variability and inspiratory muscle strength in older adults.Clinical trial registrationhttps://clinicaltrials.gov/study/NCT06269042, identifier: NCT06269042.

Effect of chest expansion resistance exercise and respiratory muscle stretching on respiratory function and gait endurance in patients with stroke.

Limited chest expansion and asymmetry in the respiratory muscles after a stroke lead to poor ventilation and reduced physical performance. To determine the effect of chest expansion resistance exercise and respiratory muscle stretching on respiratory function and gait endurance in patients with stroke. Thirty stroke patients were randomly assigned to a chest expansion resistance group (CERG), a respiratory muscle stretching group (RMSG), and a control group (CG). CERG and RMSG received chest expansion resistance and respiratory muscle stretching, respectively, 3 times a week for 8 weeks. Respiratory function, respiratory muscle strength, and gait endurance were measured before and after the intervention period. The experimental groups, CERG and RMSG, showed significant improvements in respiratory function variables (p < .05). For respiratory muscle strength variables, maximal inspiratory pressure (MIP) in the CERG and maximal expiratory pressure (MEP) in the RMSG showed significant changes compared to the CG (p < .05). Both CERG and RMSG also showed significant improvements in the 6MWT compared to the CG (p < .05). Chest expansion resistance exercise would be a more effective method, while both chest expansion resistance exercise and respiratory muscle stretching are helpful in improving respiratory function and gait endurance.

The sevoflurane concentration for light sedation in critically ill patients: A protocol for experimental study

Background: Deep-inhaled sedation is increasingly used in Thai ICUs. However, there is a lack of information regarding the level of end-tidal sevoflurane concentration during light sedation. Objectives: The study aims to determine the effective dose (ED50 and ED95) of sevoflurane concentration for light sedation (RASS score -1 to 0) in mechanically ventilated critically ill patients. Methods: This is a prospective experimental single-center study. Mechanically ventilated patients with RASS ≥ 1 who required sedation in the medical and surgical intensive care unit were enrolled. Using an up-and-down sequential allocation technique, the inhaled sevoflurane level of each patient was allocated based on the previous patient’s response. RASS score and hemodynamic parameters were monitored. The primary outcome was the ED50 and ED 95 of end-tidal sevoflurane concentration. The secondary outcomes included the length of intensive care unit stay, duration of ventilator day, the incidence of delirium, hemodynamic status, and respiratory variables changed during the study period. Hypothesis: There exist specific end-tidal sevoflurane concentrations (ED50 and ED95) that will reliably induce a target RASS score of -1 to 0 in critically ill patients who are mechanically ventilated. Conclusion: This study will provide an effective dose of inhaled sevoflurane sedation for achieving targeted light sedation levels in critically ill patients, which may have minimal effects on hemodynamics. Ethics and dissemination: This study has been approved by the Office of Human Research Ethics Committee, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Thailand, on 22nd May 2023 (COA.MURA2023/390). Trial registration: TCTR20230825001

Nebulized fentanyl does not improve exercise capacity or dyspnoea in fibrosing interstitial lung disease.

Exercise intolerance and exertional dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD) and are associated with worse prognosis and quality of life. Activation of pulmonary vagal afferents influences the ventilatory pattern and contributes to the sensation of dyspnoea. We tested the hypothesis that nebulized fentanyl, which might attenuate aberrant pulmonary afferent activity in FILD, reduces ventilation and dyspnoea while extending exercise endurance time (EET). In this randomized, single-blind, placebo-controlled study, eight FILD patients (two males, 71±6years of age) performed incremental cardiopulmonary cycle exercise tests following nebulization of either fentanyl citrate (100 µg) or 0.9% saline. Previous work indicated that this dose was unlikely to produce central effects. Comparisons between treatment conditions at rest were undertaken using Student's paired t-test, and exercise data were evaluated with two-way ANOVA with repeated measures. Dyspnoea was assessed using the Borg dyspnoea scale. Resting respiratory variables were not different following treatment with fentanyl and saline; however, resting heart rate was lower following fentanyl (P=0.002) and remained lower throughout exercise compared with placebo (P=0.008). Fentanyl did not increase EET (placebo 334±117s vs. fentanyl 348±126s, P=0.250) although overall minute ventilation was reduced slightly (mean difference: -0.97 L/min, P=0.022). There were no differences in ratings of dyspnoea intensity or unpleasantness between the conditions either at rest or at end-exercise. Nebulized fentanyl did not improve EET or exercise dyspnoea but did decrease minute ventilation during exercise, although the extent of this reduction appears clinically insignificant. These findings suggest that nebulized fentanyl is unlikely to offer significant benefits for enhancing exercise capacity in FILD.

EFFECT OF DIFFERENT TYPES OF MUSIC ON CARDIO-RESPIRATORY VARIABLES AMONG OBESE YOUNG ADULTS: A LITERATURE REVIEW

Background: Obesity is one of the major public health problems affecting every region of the globe. Obesity is a prevalent form of malnutrition that can lead to adverse metabolic effects. The risk of heart disease and diabetes increases steadily with increasing body mass index (BMI). Exercise physiology shows a growing interest in the possible physiological and psychological effects of music. Exercisers who listen to music are encouraged to keep up the effort while being diverted from their physical exhaustion. Objectives: To evaluate the effects of different types of music on cardio and respiratory Variables among overweight and obese young adults. Method: A review of observational, experimental, randomized control trials, and cross-sectional studies were performed. SCOPUS, Google Scholar, EBSCO and PubMed were searched using music, HRV, and obese, overweight young adults. Result: A total of 37 studies were identified of which 13 studies were published between 2011-2023 and were included in the study. 6 studies included in our study showed positive effects of music on the rate of perceived exertion, and cardiorespiratory fitness which could be a good strategy for obese young adults. Conclusion: This study concluded that there is a significant relationship between the different types of music along with exercise on cardiorespiratory fitness in young obese adults. The moderate quality of evidence in many studies indicates a need for further research to solidify these findings and explore new therapeutic avenues.

Effects of 60Coγ-irradiation combined with sodium dehydrogenate on post-harvest preservation and physiological indices of Volvariella volvacea.

Volvariella volvacea is a mushroom known for its high palatability and nutritional value. However, it is susceptible to spoilage thus making it challenging to preserve and keep fresh after harvest, resulting in constraints in long-distance transportation and long-term storage. This study aimed to investigate the feasibility of using irradiation and sodium dehydrogenate (SD) as a preservative in the preservation process of V. volvacea. The effects of three treatments of 0.8 kGy 60Coγ irradiation (B), 0.04% SD (C), combined with 0.04% SD and 0.8 kGy 60Coγ irradiation (A) on the postharvest freshness of V. volvacea were investigated. The assessment indices for V. volvacea, including appearance, browning rate, weight loss, respiration rate, MDA content, antioxidant enzyme activities, vitamin C (Vc), and soluble protein content, were measured and compared. The three treatments were compared to determine the changes in storage time over 7 days post-harvest. The results demonstrated that the hardness of the fruiting body exhibited a significant increase of 81.19%, 97.96% and 168.81% in comparison to the control, B and C, respectively, following the application of the treatment A. Compared to the control group, the soluble protein content was significantly increased by 20.28%. Respiration intensity and browning rate were significantly lower in the control treatment, decreasing by 35.07% and 45.49% respectively. On the 6th day of storage, the activities of SOD and POD increased by 81.06% and 73.71%, respectively, compared to the control, which significantly delayed the senescence of the fruiting bodies. The Vc content was significantly increased by 50.27%, 133.90%, and 101.39% in treatment B, which received 0.8 kGy 60Coγ irradiation alone, compared to the control, treatment A, and treatment C, respectively. The treatment C alone significantly reduced respiratory intensity and MDA variables by 39.55% and 31.01%, respectively, compared to the control. The findings can provide theoretical references and technical support for extending the preservation period of V. volvacea after harvesting by using irradiation and sodium dehydrogenate as a preservative.

Respiratory effects of prone position in COVID-19 acute respiratory distress syndrome differ according to the recruitment-to-inflation ratio: a prospective observational study

BackgroundImprovements in oxygenation and lung mechanics with prone position (PP) in patients with acute respiratory distress syndrome (ARDS) are inconstant. The objectives of the study were (i) to identify baseline variables, including the recruitment-to-inflation ratio (R/I), associated with a positive response to PP in terms of oxygenation (improvement of the ratio of arterial oxygen partial pressure over the inspired oxygen fraction (PaO2/FiO2) ≥ 20 mmHg) and lung mechanics; (ii) to evaluate whether the response to the previous PP session is associated with the response to the next session.MethodsIn this prospective, observational, single-center study in patients who underwent PP for ARDS due to COVID-19, respiratory variables were assessed just before PP and at the end of the session. Respiratory variables included mechanical ventilation settings and respiratory mechanics variables, including R/I, an estimate of the potential for lung recruitment compared to lung overinflation.ResultsIn 50 patients, 201 PP sessions lasting 19 ± 3 h were evaluated. Neuromuscular blockades were used in 116 (58%) sessions. The PaO2/FiO2 ratio increased from 109 ± 31 mmHg to 165 ± 65 mmHg, with an increase ≥ 20 mmHg in 142 (71%) sessions. In a mixed effect logistic regression, only pre-PP PaO2/FiO2 (OR 1.12 (95% CI [1.01–1.24])/every decrease of 10 mmHg, p = 0.034) in a first model and improvement in oxygenation at the previous PP session (OR 3.69 (95% CI [1.27–10.72]), p = 0.017) in a second model were associated with an improvement in oxygenation with PP. The R/I ratio (n = 156 sessions) was 0.53 (0.30–0.76), separating lower- and higher-recruiters. Whereas PaO2/FiO2 improved to the same level in both subgroups, driving pressure and respiratory system compliance improved only in higher-recruiters (from 14 ± 4 to 12 ± 4 cmH2O, p = 0.027, and from 34 ± 11 to 38 ± 13 mL/cmH2O, respectively, p = 0.014).ConclusionsA lower PaO2/FiO2 at baseline and a positive O2-response at the previous PP session are associated with a PP-induced improvement in oxygenation. In higher-recruiters, lung mechanics improved along with oxygenation. Benefits of PP could thus be greater in these patients.

Comparative study between lateral versus latero-ventral quadratus lumborum block for perioperative analgesia in canine laparoscopic ovariectomy

ObjectiveTo compare the perioperative analgesic effect of lateral versus latero-ventral quadratus lumborum block (QLB) in dogs undergoing laparoscopic ovariectomy. Study designRandomized, blinded clinical study. AnimalsA total of 15 client-owned female dogs undergoing laparoscopic ovariectomy. MethodsAnimals were randomly assigned to receive a bilateral QLB, performed with 0.3 mL kg–1 ropivacaine 0.5%, either with lateral (group LQLB, n = 7) or latero-ventral approach (group LVQLB, n = 7). Dogs were premedicated intramuscularly with methadone 0.2 mg kg–1 and dexmedetomidine 3 μg kg–1. General anaesthesia was induced intravenously (IV) with propofol and maintained with isoflurane. Cardiovascular and respiratory variables were continuously monitored and recorded every 5 minutes during surgery. Fentanyl 3 μg kg–1 was administered IV if there was a 20% increase in heart rate and/or mean arterial pressure from previous values recorded 5 minutes before. Meloxicam 0.2 mg kg–1 was administered IV to all dogs during recovery. The short-form of the Glasgow Composite Pain Scale was used hourly for 8 hours post-QLB. Methadone 0.2 mg kg–1 was administered IV when pain score was ≥ 6/24. A chi-square test compared the number of dogs requiring intraoperative rescue fentanyl. A Friedman test with a Dunn’s post hoc was used to evaluate the trend in postoperative pain scores within each group, and a Mann–Whitney U test compared scores between the groups at each time point; p < 0.05. ResultsSignificantly fewer dogs required intraoperative rescue fentanyl in group LQLB than in group LVQLB. No dog required postoperative rescue methadone, and there were no significant differences in pain scores. Conclusions and clinical relevanceBilateral QLB performed with lateral approach reduced the number of dogs requiring intraoperative rescue analgesia in comparison with the latero-ventral approach. No differences were detected postoperatively, possibly owing to the confounding effects of methadone, dexmedetomidine and meloxicam.

CARDIORESPIRATORY EFFECTS OF VATINOXAN IN BLESBOK (DAMALISCUS PYGARGUS PHILLIPSI) IMMOBILIZED WITH THIAFENTANIL-MEDETOMIDINE.

Combinations of a low dose of opioid, such as thiafentanil, and a high dose of medetomidine, are increasingly being used for immobilization of African ungulates. Both drugs can have undesirable cardiorespiratory effects. In this study we assessed whether vatinoxan, a peripherally acting alpha2-adrenergic receptor antagonist, can be used to alleviate some of these effects without affecting the immobilization quality. Eight healthy, female, boma-confined blesbok (Damaliscus pygargus phillipsi), weighing a mean (SDtion) of 56.8 (4.4) kg, were immobilized twice in a randomized cross-over study with a 2-wk washout period using (1) 0.5 mg thiafentanil + 1.5 mg medetomidine (TM), (2) TM + vatinoxan: 0.5 mg thiafentanil + 1.5 mg medetomidine + 15 mg vatinoxan per milligram medetomidine (total of 22.5 mg, administered intramuscularly at 10 min post recumbency). Heart rate, respiratory rate, rectal temperature, oxygen saturation (SpO2), arterial blood pressure, and sedation scores from 1 to 5 (1 = limited effect; 5 = excessively deep) were measured every 5 min. Arterial blood gases (PaO2 and PaCO2) were measured at 10, 15, 25, and 35 min postrecumbency and the alveolar--arterial oxygen gradient (P[A-a]O2) was calculated. Induction times and immobilization quality did not differ between groups. The heart rate was significantly higher and the mean arterial pressure significantly lower in blesbok after receiving vatinoxan. All animals were hypoxemic and there were no significant differences in the respiratory rates, PaO2, PaCO2, SpO2, or P(A-a)O2 gradients at any time point. Although vatinoxan did not improve respiratory variables and blood oxygenation in these animals, the change in cardiovascular variables may suggest that it improves tissue perfusion, a positive outcome that requires further investigation.

Effect of Inspiratory Muscle Training on Outcomes After Cardiac Surgery: A Comprehensive Meta-Analysis of Randomized Controlled Trials.

Inspiratory muscle training (IMT) has emerged as a potential intervention to improve respiratory outcomes for patients undergoing cardiac surgery. However, the extent of the IMT effects on preoperative and postoperative respiratory metrics remains uncertain. Hence, we designed this study to determine the effects of IMT on various outcomes of patients undergoing cardiac surgery. We conducted a comprehensive meta-analysis of studies evaluating the impact of preoperative and postoperative IMT on various respiratory variables and postsurgical outcomes. We synthesized data from multiple studies, encompassing diverse patient populations and IMT protocols. The key outcomes included the maximal inspiratory pressure (MIP), forced expiratory volume in 1sec (FEV1), forced vital capacity (FVC), and others. Our meta-analysis results showed that preoperative IMT significantly improved the MIP values with a pooled standard mean difference (SMD) of 0.62. The hospital stay length was also reduced with a SMD of-0.4. Other variables such as FEV1 and FVC also improved significantly. Postoperative IMT improved the MIP and peak flow rate values, but the evidence was less robust than with preoperative interventions. We observed high heterogeneity across studies for several outcomes and found evidence of publication bias for some postoperative measures. Both preoperative and postoperative IMT offer benefits for patients undergoing operations, especially by enhancing respiratory muscle strength and potentially reducing hospital stays. However, the presence of heterogeneity and publication bias underscores the need for further standardized research to consolidate these findings and standardize IMT protocols for optimal patient outcomes.

Physiological effects of high-flow nasal cannula during sustained high-intensity exercise in healthy volunteers: a randomised crossover trial

IntroductionHigh-flow nasal cannula (HFNC) has increased exercise capacity in patients with chronic respiratory diseases. However, it remains unknown whether HFNC impacts respiratory physiological variables during exercise. This study aimed to evaluate the effect of HFNC on respiratory physiological variables during sustained high-intensity exercise in healthy volunteers.MethodsWe performed a single-center, open-label, and randomised crossover trial to compare HFNC (60 L·min−1) and Sham-HFNC (2 L·min−1) interventions during a constant work-rate exercise (CWRET) through randomised order. The primary outcome was ΔPes, and the secondary outcomes were other variables of inspiratory effort, ventilation distribution, ventilatory variables, and clinical assessment. We evaluated volunteers at seven-time points (Baseline= T0; CWRET= T1-T2-T3 (minutes: 1′, 4′ and 6′); Cooldown-period= T4-T5-T6 (minutes: 1′; 6′;10′)) in both interventions.ResultsFourteen healthy volunteers (50% women; age: 22 [21–27] years) were enrolled. Mean differences in ΔPes decreased to favor the HFNC intervention compared to Sham-HFNC at T2 (−2.8 cmH2O; 95%CI −5.3 to −0.3), as well as the sPTPmin at T2 (−86.1 cmH2O×s·min−1;95%CI −146.2 to −26.1), and T3 (−79.9 cmH2O×s·min−1;95%CI −142.3 to −17.6). The standard deviation of the regional ventilation delay index was also lower with HFNC compared to Sham-HFNC (T1: −1.38; 95%CI −1.93 to −0.83; T2: −0.71; 95%CI −1.27 to −0.16). There was decreased dyspnea to favor the HFNC, but sPTP-per-breath, spatial distribution ventilation indexes, ventilatory variables, and clinical assessments were nonsignificant between interventions.ConclusionHFNC intervention reduces respiratory effort, dyspnea and improves temporal ventilation distribution in healthy volunteers during CWRET.

Comparison of dexmedetomidine versus nalbuphine in ketamine based procedural sedation for pediatric cathlab procedures: A prospective double blinded randomized trial

: The aim of the current study was to compare the effects of nalbuphine and dexmedetomidine as premedication sedative agent for ketamine based deep sedation on hemodynamics, sedation level and need for additional boluses of ketamine, and recovery time in pediatric patients undergoing various cardiac catheterization procedure.: Sixty pediatric patients undergoing cardiac catheterization were enrolled in the current study. Patients were randomly distributed to two equal groups of 30 patients each: Group D and Group N. Patients randomized to Group D received a bolus of dexmedetomidine at 1 μg/kg over 10 min and Group N received a bolus of nalbuphine 0.1 mg/kg over 10min. In both the groups patients were induced with Inj ketamine 2mg/kg. After induction dose inj ketamine 0.5mg/kg boluses were given to achieve and maintain the target Ramsay Sedation Score (RSS)≥ 4. Mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (SPO2), and sedation scores were recorded. Recovery time, perioperative adverse events, and total ketamine consumption required for anesthesia maintenance were also recorded.: There was significant decreased in HR from baseline in group D at 10, 20, and 30min of the procedure with no significant difference as regards the MAP between the two study groups. Ketamine consumption in group N was significantly lower than in group D to maintain RSS in desired range. The recovery time was significantly shorter in group N when compared with group D. Respiratory variables were maintained in both the groups with two patients reported airway obstruction which was partial. No significant difference was found in intra and postoperative adverse effect between the groups. : The nalbuphine was found to be superior to dexmedetomidine as a premedication sedation for pediatric cathlab procedure in terms of reduced consumption of ketamine for adequate intraoperative sedation to conduct the procedure with better hemodynamic control and the shorter recovery time.

The degree of respiratory depression according to the effect-site concentration in remimazolam target-controlled infusion: A randomised controlled trial.

Remimazolam is not only associated with a lower incidence of respiratory depression than propofol but also in itself has the risk of respiratory depression. We investigated respiratory depression following remimazolam infusion, targeting different effect-site concentrations using target-controlled infusion. A prospective, double-blind, randomised controlled study. Tertiary hospital, Suwon, South Korea, from April 2022 to November 2022. One hundred and seven patients scheduled for general anaesthesia were randomised into three groups targeting remimazolam effect-site concentrations of 500 (RMZ-500) ( n = 36), 1000 (RMZ-1000) ( n = 35) and 1500 ng ml -1 (RMZ-1500) ( n = 36). Remimazolam was solely infused for 10 min according to target effect-site concentrations. According to the degree of SpO 2 decrease, oxygen desaturations were managed with the following respiratory supports: jaw-thrust for SpO 2 less than 97%, 100% oxygen delivery for SpO 2 less than 93% and assisted ventilation for SpO 2 less than 90%. The incidence of each respiratory support, along with respiratory variables (at baseline, 5 min and 10 min after remimazolam infusion) and loss of consciousness were observed for 10 min after remimazolam target-controlled infusion. Both RMZ-1000 and RMZ-1500 required more frequent respiratory support than RMZ-500 (both P < 0.001), with nearly identical frequencies between RMZ-1000 and RMZ-1500. In terms of respiratory support, the incidence of assisted ventilation was significantly lower in RMZ-500 (2.8%) than RMZ-1000 (48.6%) and RMZ-1500 (50%) ( P < 0.001). RMZ-1000 and RMZ-1500 achieved loss of consciousness in all patients; RMZ-500 only achieved loss of consciousness in 86.1% of patients ( P = 0.010). In patients who maintained spontaneous respiration, tidal volume decreased by 41 to 48% and respiratory rate increased by 118 to 158% at 5 and 10 min, significantly compared to baseline in all groups ( P < 0.001). Remimazolam infusion, like that of other benzodiazepines, led to respiratory depression, which was more prominent at higher target effect-site concentrations. Therefore, appropriate countermeasures should be developed to prevent oxygen desaturation. CRIS ( https://cris.nih.go.kr ), identifier: KCT0006952.

Comparison of acute physiological responses between one long and two short sessions of moderate-intensity training in endurance athletes.

To compare acute physiological responses and perceived training stress between one long and two short time- and intensity-matched sessions of moderate-intensity training in endurance athletes. Fourteen male endurance athletes (VO2max: 69.2 ± 4.2mL·min-1·kg-1) performed one 6 × 10-min interval session (SINGLE) and two 3 × 10-min interval sessions interspersed with 6.5h recovery (DOUBLE) of moderate-intensity training on two separate days, while running in the laboratory, using a counterbalanced cross-over trial. The two training days were separated into a first part/session (interval stage 1-3) and second part/session (interval stage 4-6). Respiratory variables, heart rate (HR), blood lactate concentrations (BLa), and rating of perceived exertion (RPE) were collected during sessions, whereas supine heart rate (HR) was assessed in a 60-min recovery period following sessions. Measures of perceived training stress (1-10) were assessed in the morning of the subsequent day. HR, Bla, and RPE increased in the second compared to first part of SINGLE (168 ± 7 vs. 173 ± 7bpm, 2.60 ± 0.75 vs. 3.01 ± 0.81mmol·L-1, and 13.4 ± 1.0 vs. 14.8 ± 1.1-point, respectively, all p < 0.05). HR and Bla decreased in the second compared to first session of DOUBLE (171 ± 9 vs. 166 ± 9bpm and 2.72 ± 0.96 vs. 2.14 ± 0.65mmol·L-1, respectively, both p < 0.05). SINGLE revealed higher supine HR in the recovery period following sessions (65.4 ± 2.5 vs. 60.7 ± 2.5bpm p < 0.05), session RPE (sRPE, 7.0 ± 1.0 vs. 6.0 ± 1.3-point, p = .001) and sRPE training load (929 ± 112 vs. 743 ± 98, p < 0.001) compared to DOUBLE. In the subsequent morning, increased levels of perceived fatigue and muscle soreness were observed following SINGLE compared to DOUBLE (7.0 ± 2.5 vs. 8.0 ± 1.0-point, p = .049 and 6.0 ± 2.5 vs. 7.0 ± 2.5-point, p = .002, respectively). One long moderate-intensity training session was associated with a duration-dependent "drift" in physiological responses compared to two short time- and intensity-matched sessions, thereby suggesting a higher overall training stimulus. Simultaneously, the lower cost of the two shorter sessions indicates that such organization could allow more accumulated time at this intensity. Overall, these findings serve as a starting point to better understand the pros and cons of organizing moderate-intensity training as one long versus shorter sessions performed more frequently (e.g., as "double threshold training") in endurance athletes.

A Novel Non-invasive Predictor Measure of Left Atrial Pressure and Practical Implicates in High Frequency Ventilation: Theory.

A new prototype of ventilator mode, based on high-frequency ventilation (HFV), aims to address the interrelations among diverse respiratory variables, several intercardiovascular parameters rapports, and instantaneously the intrarespiratory and cardiac interactions. This article proposes a logarithmic network of integrated correlation ratio H/V, R correlation, that primarily relates both dependent respiratory (V) and independent hemodynamic variables (H). Given a constant steady state of the heart and vasculature, a difference between calculated ratio (R calc), and optimized ratio (R opt) could be utilized to adjust many aspects of several parameters and outcomes in critically ill patients. The central venous pressure (CVP) waveanalysis aims to approachseveral cardiovascular parameters, endpoints of left atrial (LA) pressure, and the cardiac output (CO) with the help of thermodilution curve analysis. This might result in several innovative formulas of mathematical base. Their relevant clinical implicates demonstrated a wide area of normalized distribution capacity (Cd), systemic vascular capacity (Cs), pulmonary vascular capacitance (Cp), pulmonary vascular resistance (PVR), and mean pulmonary artery pressure (MPAP). The authors claim that prepared software programming helps network integration of all these variables, feeding back and addressing the prototypeof novel mode for the oldnew applicationof HFV. One potential unique criterion is adjusting LA and ultimately CO through a feedback control mechanism. Though this all sounds very plausible, the reader must be reminded that everything in this work is based on the most expected speculations and experience and could be potentially different than that in vivo.More importantly, animalexperimental studies are warranted.

Comparison of subarachnoid administration of low-dose bupivacaine and lidocaine in healthy goats.

This study aimed to compare the effects of low-dose subarachnoid injections of 2% lidocaine (LIDO) and 0.5% bupivacaine (BUPI) in goats. 6 healthy, privately owned female goats. In this randomized blind crossover clinical trial, each goat received 0.05 mL/kg-1 of LIDO, BUPI, or sterile saline solution into the lumbosacral subarachnoid space, with a seven-day washout. Cardiorespiratory variables, rectal temperature, and somatosensory (pinprick) and motor (ataxia) functions were recorded at baseline (time 0) and 2, 5, 10, 15, and 30 minutes after injection, then every 20 minutes until the goat was standing and able to walk. Time to regain somatosensory and motor functions was compared between treatments using Kaplan-Meier survival curves and the Cox proportional hazards model. Linear mixed-effects models were used to compare cardiorespiratory variables between treatments and over time. A P value ≤ .05 was considered significant. Somatosensory recovery was longer with BUPI, though not statistically significant. The median time to stand was 50 (50, 67) minutes after LIDO injection and 104 (101, 156) minutes after BUPI injection (P = .031). The median time to walk was 72 (54, 85) minutes after LIDO versus 225 (220, 245) minutes after BUPI injection (P = .031). Cardiovascular and respiratory variables showed no significant differences between treatments. Despite prolonged ataxia with BUPI, pinprick sensation recovery did not differ. At reduced doses, both LIDO and BUPI are deemed acceptable for short procedures of the flank, pelvic limb, or tail in healthy goats.

Comparison of cardiopulmonary effects of propofol, ketamine–propofol and isoflurane anesthesia in the domestic chicken (Gallus gallus domesticus)

ObjectiveTo compare the effects of propofol, ketamine–propofol and isoflurane, at similar anesthetic depth, on cardiopulmonary variables in unpremedictated chickens. Study designProspective, randomized, crossover experimental trial. AnimalsA total of 10 male Leghorn domestic chickens, aged 3 months and body mass 1.4–2.0 kg. MethodsBirds were randomly assigned to each of three anesthetic protocols, 7 days apart: intravenous propofol, intravenous ketamine–propofol or isoflurane. Anesthesia was induced (indicated by loss of righting reflex and tracheal intubation) and maintained with propofol (10 mg kg–1 minute–1, then 1.1 mg kg–1 minute–1), ketamine–propofol (5 mg mL–1 ketamine and 5 mg mL–1 propofol combined; 10 mg kg–1 minute–1, then 1.1 mg kg–1 minute–1) or isoflurane [5% vaporizer setting initially, then end-tidal concentration (Fe′Iso) of 2%] for 65 minutes. Anesthesia was maintained at a similar anesthetic depth based upon positive or negative responses to toe pinch. Heart rate (HR), respiratory rate (fR), noninvasive arterial blood pressure and arterial blood gases were measured during anesthesia. Propofol or ketamine–propofol infusion rates and Fe′Iso required to prevent movement in response to a noxious stimulus and recovery times were recorded. ResultsAnesthesia induction dose was 9.0 ± 0.8 (mean ± SD) and 12.2 ± 0.3 mg kg–1 for propofol and ketamine–propofol, respectively. Propofol and ketamine–propofol infusion rates and Fe′Iso required to prevent movement in response to the noxious stimulus were 0.88 ± 0.14 mg kg–1 minute–1, 0.92 ± 0.14 mg kg–1 minute–1 and 1.45 ± 0.28%, respectively. Cardiopulmonary variables remained clinically acceptable, but ketamine–propofol was associated with a significantly higher HR (p = 0.0001) and lower fR (p = 0.0001). Time to extubation did not differ among treatments. Conclusions and clinical relevanceCardiovascular and respiratory variables were maintained within normal ranges in all treatments. Coadministration of ketamine with propofol significantly reduced the induction and maintenance dose of propofol.

Impacto de la oxigenoterapia a alto flujo a través de la insuflación de gas a alta velocidad sobre la fracción de engrosamiento diafragmático en sujetos sanos

ObjectiveThe primary objective of this study was to evaluate the impact of high-flow nasal cannula oxygen therapy [HFNC] on the diaphragm thickening fraction. DesignProspective, descriptive, cohort study SettingThe study was conducted in the Physiology and Respiratory Care Laboratory, Intensive Care Unit, Hospital Británico de Buenos Aires. ParticipantsThirteen healthy subjects >18 years old InterventionsHigh-flow nasal cannula oxygen therapy Main variables of interestDemographic data (age and gender), anthropometric data (weight, height, and body mass index), and clinical and respiratory variables (Diaphragm thickening fraction [DTf], esophageal pressure swing, respiratory rate [RR], esophageal pressure-time product per minute [PTPes/min]). ResultsMedian DTf decreased significantly as flow increased (P<.05). The baseline DTf measurement was 21.4%, 18.3% with 20 l/m, and 16.4% with 40 l/m. We also observed a significant decrease in RR as flow increased in HFNC (P<.05). In the 8 subjects with recordings, the PTPes/min was 81.3 cmH2O/sec/min (±30.8) and 64.4 cmH2O/sec/min (±25.3) at baseline and 40 l/m respectively (P=.044). ConclusionsThe use of high-flow oxygen therapy through nasal cannula of HFNC in healthy subjects decreases the DTf and RR in association with increased flow. In addition, the use of 40 l/m flow may reduce the muscular work associated with respiration.

Remote Respiratory Variables Tracking With Biomedical Radar-Based IoT System During Sleep

Remote Respiratory Variables Tracking With Biomedical Radar-Based IoT System During Sleep

Interactions between Cognitive, Affective, and Respiratory Profiles in Chronic Respiratory Disorders: A Cluster Analysis Approach.

This study conducted at Leamna Pulmonology Hospital investigated the interrelations among cognitive, affective, and respiratory variables within a cohort of 100 patients diagnosed with chronic respiratory conditions, utilizing sophisticated machine learning-based clustering techniques. Spanning from October 2022 to February 2023, hospitalized individuals confirmed to have asthma or COPD underwent extensive evaluations using standardized instruments such as the mMRC scale, the CAT test, and spirometry. Complementary cognitive and affective assessments were performed employing the MMSE, MoCA, and the Hamilton Anxiety and Depression Scale, furnishing a holistic view of patient health statuses. The analysis delineated three distinct clusters: Moderate Cognitive Respiratory, Severe Cognitive Respiratory, and Stable Cognitive Respiratory, each characterized by unique profiles that underscore the necessity for tailored therapeutic strategies. These clusters exhibited significant correlations between the severity of respiratory symptoms and their effects on cognitive and affective conditions. The results highlight the benefits of an integrated treatment approach for COPD and asthma, which is personalized based on the intricate patterns identified through clustering. Such a strategy promises to enhance the management of these diseases, potentially elevating the quality of life and everyday functionality of the patients. These findings advocate for treatment customization according to the specific interplays among cognitive, affective, and respiratory dimensions, presenting substantial prospects for clinical advancement and pioneering new avenues for research in the domain of chronic respiratory disease management.