Search Results (84)

The main distinction between open and laparoscopic ovariectomy (OVE) is pneumoperitoneum (PNP) and anesthesia management. The objective of this study was to evaluate the effect of laparoscopic and open OVE on plasma cortisol, oxidative stress (OS), and cardiorespiratory parameters in dogs under the same anesthesia protocol. Twenty healthy female dogs were assigned to laparotomy OVE (LPTOVE, n = 10) and laparoscopic OVE (LAPOVE, n = 10) groups. OS was assessed using the total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI). Blood samples were collected prior to sedation (T0); prior to surgical incision (T1); prior to surgical closure in the LPTOVE group; and prior to the deflation of CO₂ in the LAPOVE group (T2), 2 h after the surgery (T3). The monitored cardiorespiratory parameters were heart rate, respiratory rate, and end-tidal CO₂ (EtCO₂). Cortisol levels at T3 were markedly elevated in the LPTOVE group compared to the LAPOVE group. No substantial changes in TOS, TAS, or OSI between groups were detected. In the LAPOVE group, TOS diminished at T2, but TAS declined and OSI escalated at T3. EtCO₂ levels were elevated in the LAPOVE group at the end of the procedure. These findings support laparoscopic OVE as a less traumatic alternative to open surgery, with careful management of PNP and anesthesia recommended to minimize postoperative stress. Full article

Backround and Objectives: Basketball performance is shaped by repeated high-intensity actions interspersed with brief recovery. Conventional continuous or strictly incremental testing may not fully capture short active-recovery dynamics relevant to stop-and-go sports. Material and Methods: This study applied a VT₂-referenced progressive–intermittent treadmill protocol and focused on 60-s active-recovery kinetics to describe effort tolerance in an applied basketball setting. Basketball players from Mureș County completed anthropometry (24 h pre-test, fasted) and a single laboratory visit. Pre-test training and diet were standardized for 48 h (submaximal training; predominantly carbohydrate intake). CPET was performed in 3-min stages (6.5 km·h⁻¹ start; +0.7 km·h⁻¹ per stage) and stopped at RER = 1.00 and/or blood lactate = 4.0 mmol·L⁻¹ (operational VT2). After 3 min active recovery, participants completed six 60-s high-speed bouts separated by 60-s active recovery intervals (AR1–AR6), with intensities prescribed at 120–180% of VT2-derived speed, followed by an 8-min active recovery. For each AR interval, linear regression over 0–60 s yielded slopes for VO₂, VO₂/HR, VCO₂, V̇E, VE/VO₂, VE/VCO₂, and PetCO₂. Results: VT₁ was determined at 2.29 m·s⁻¹ (VO₂ 32 mL·min⁻¹·kg⁻¹) and VT2 at 3.07 m·s⁻¹ (VO₂ 42 mL·min⁻¹·kg⁻¹). Maximal intermittent speed was 5.33 m·s⁻¹ (VO₂ 45.5 mL·min⁻¹·kg⁻¹; RER 1.06; PetCO₂ 38 mmHg). VO₂ differed across successive bouts (p = 0.0001), while PetCO₂ showed a small downward drift across repetitions. Peak indices (max speed, VE/VCO₂max, PetCO₂max, VEmax) were associated with phase-specific recovery slopes across early, mid, and late recovery periods (false discovery rate–adjusted correlations). Lactate decreased over 8 min, but lactate change rates were not associated with peak indices. Conclusions: The VT₂-referenced progressive–intermittent protocol appears feasible in basketball players and provides phase-dependent recovery information that complements conventional peak CPET outcomes, with potential relevance for applied team settings. Full article

Background/Objectives: Despite increasing interest in high-intensity exercise and cerebrovascular function, the effects of maximal sprint exercise on cerebrovascular reactivity (CVR), a key indicator of vascular health, remain unclear. Methods: This study investigated the acute effects of a 30-s all-out cycling sprint (Wingate Anaerobic Test, WAnT), on CVR to hypocapnia in 24 healthy young adults (12 males). Following familiarisation and a $\dot{\mathrm{V}}$O_2max test, participants completed an experimental session where CVR was assessed at rest and 30 min post-WAnT. CVR was evaluated using a 1-min voluntary hyperventilation protocol (25 breaths·min⁻¹), with middle cerebral artery blood velocity (MCAv) measured via transcranial Doppler ultrasound and end-tidal CO₂ (P_ETCO₂) recorded breath-by-breath. CVR was calculated as the absolute change in MCAv per 1 mmHg change in P_ETCO₂ from the final 10 s of hyperventilation. Results: Resting MCAv and P_ETCO₂ were significantly reduced post-WAnT (p < 0.01 and p < 0.001 respectively). Consequently, the reductions in MCAv and P_ETCO₂ during hyperventilation were attenuated after exercise in both males and females (p < 0.01 and p < 0.001 respectively). Despite these changes, CVR remained unaltered in both sexes following WAnT (males: 1.79 ± 0.35 vs. 1.59 ± 0.26 cm·s⁻¹·mmHg⁻¹, p = 0.09; females: 2.01 ± 0.44 vs. 2.01 ± 0.46 cm·s⁻¹·mmHg⁻¹, p = 0.97). However, post-exercise CVR was significantly lower in males than females, despite no baseline sex differences (p = 0.01). Conclusions: Cerebrovascular reactivity to hypocapnia is preserved 30 min after a single bout of maximal sprint exercise in healthy young adults. Notably, females demonstrated a more favorable maintenance of CVR post-exercise compared to males, suggesting potential sex differences in CVR following maximal sprint exercise. Full article

Background: Awake carotid endarterectomy (CEA) under local anesthesia demands an optimal sedation strategy that ensures patient comfort while preserving the ability for real-time neurological assessment. Dexmedetomidine (DEX) and remifentanil (REMI) are widely used agents, but direct comparisons in this setting remain scarce. Methods: Exploratory, retrospective, single-center study of awake CEA (March–July 2019). DEX or REMI infusions were titrated to a Richmond Agitation–Sedation Scale (RASS) of −1 to −2. Outcomes were sedation failure (RASS ≥ +2 despite maximum infusion rate), bradycardia, hypotension, and neurologic events. Statistical analyses used χ² test (categorical variables) and Student’s t-test or Mann–Whitney test (continuous variables). Associations were assessed with Firth’s logistic regression (univariable and bivariate models), reporting odds ratios (OR) with 95% confidence intervals (CI_95%). Trends in the Bispectral Index (BIS), hemodynamic, and respiratory parameters were assessed using two-way repeated-measures Analysis of Variance (ANOVA). A p-value < 0.05 was considered significant. Results: Fifty-two patients were included (DEX = 25; REMI = 27). DEX group showed more frequent sedation failure (32.0% vs. 3.7%; p = 0.020), bradycardia (36.0% vs. 3.7%; p = 0.009), and hypotension (28.0% vs. 0%; p = 0.011). DEX was associated with increased risk in sedation failure (OR 8.58, CI_95% 1.70–85.81), bradycardia (OR 10.17, CI_95% 2.05–101.21), and hypotension (OR 22.30, CI_95% 2.46–2959.60); the direction of associations remained consistent in bivariate models adjusted for baseline confounders. ANOVA showed group-by-time interactions for BIS, heart rate, mean arterial pressure, and end-tidal CO₂. No intraoperative complications or adverse outcomes were observed. Conclusions: In this retrospective cohort of awake CEA, DEX was associated with higher rates of sedation failure and hemodynamic adverse events compared with REMI, without an apparent impact on procedural success. Given non-random allocation and baseline imbalances, these findings are hypothesis-generating and warrant confirmation in larger, robust, and prospective studies. Full article

Laparoscopic salpingectomy is a minimally invasive surgery that requires careful anesthetic management due to the effects of intra-abdominal gas insufflation. In this retrospective study, baboons (Papio hamadryas) were treated with two induction protocols: medetomidine–ketamine (MK; n = 16) and medetomidine–tiletamine–zolazepam (MZ; n = 12) via intramuscular injection. A laryngeal mask (LMA) was used for airway management and anesthesia was maintained with isoflurane in 100% oxygen. For statistical analysis, the following parameters were analyzed via two-way ANOVA: heart rate (HR), respiratory rate (RR), systolic, diastolic, and mean arterial blood pressure (SAP, DAP, and MAP), end-tidal carbon dioxide (EtCO₂), and peripheral oxygen saturation (SpO₂) recorded five minutes before pneumoperitoneum (PREP), after abdominal insufflation (PP1), at 10 (PP2) and 20 (PP3) minutes post-insufflation, and 5 min after pneumoperitoneum interruption (POSTP). HR and RR were statistically significantly higher (p < 0.05) in the MK group compared to the MZ group at all time points of the study. EtCO₂ was significantly higher (p < 0.05) in the MZ group at PP2, PP3, and POSTP time points. The incidence of hypotension was significantly greater in the MZ group (45.5%) compared to the MK group (6.25%). Hypercapnia was observed in all baboons sedated with the MZ protocol compared to 12.5% of the MK group. As a result, the MK protocol provided greater cardiorespiratory stability during laparoscopic surgery. Full article

Anesthetic protocols for non-invasive immobilization of Black Vultures (Coragyps atratus) and Turkey Vultures (Cathartes aura) for procedures lasting up to two hours are lacking. This study directly evaluated the safety and efficacy of a multimodal anesthetic protocol in 11 Black Vultures and 4 Turkey Vultures undergoing electroretinography (ERG). Vultures were anesthetized with intramuscular dexmedetomidine (5 μg/kg), midazolam (0.2 mg/kg), butorphanol (0.2 mg/kg), and ketamine (5 mg/kg) (DMBK), followed by isoflurane induction and maintenance. All vultures were mechanically ventilated to maintain consistent end-tidal CO₂. Monitored parameters included sedation and recovery quality, heart and respiratory rates, hemoglobin oxygen saturation, non-invasive blood pressure, body temperature, and end-tidal concentrations of CO₂, isoflurane, and oxygen. All vultures achieved profound sedation with smooth induction and a median isoflurane maintenance concentration of 1.4% for approximately two hours. Recovery was rapid and uneventful. Heart rates ranged from 60 to 119 beats/min. Mean arterial blood pressure averaged 149 mmHg in Black Vultures and 158 mmHg in Turkey Vultures, with Turkey Vultures showing significantly higher diastolic pressure. A second-degree heart block was detected in one Black Vulture but required no treatment. All ERG procedures were completed successfully. The DMBK protocol provided profound sedation in both species, maintained key cardiorespiratory parameters, including heart rate and arterial blood pressure, within a clinically acceptable range throughout isoflurane maintenance, and enabled uneventful rapid recovery. These findings support DMBK with the cardiorespiratory monitoring system as a safe and effective regimen for anesthetizing vultures and likely other similarly sized raptors requiring non-invasive immobilization. Full article

Background: Hemodynamic management in veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is inherently complex, as extracorporeal circulation profoundly alters preload, afterload, ventriculo-arterial coupling and tissue perfusion. This review summarizes current and emerging monitoring strategies to guide initiation, maintenance and weaning. Methods: A structured literature search was performed in PubMed and Scopus (1990–2025), including clinical studies, consensus statement and expert reviews addressing hemodynamic monitoring in V-A ECMO. Results: A multiparametric framework is required. Echocardiography remains central for assessing biventricular performance, aortic valve dynamics and ventricular unloading. Pulmonary artery catheterization provides complementary data on filling pressures, cardiac output and global oxygen balance. Metabolic indices such as lactate clearance and veno-arterial CO₂ gap, together with regional oximetry (NIRS), inform the adequacy of systemic and tissue perfusion. Microcirculatory monitoring, though technically demanding, has shown prognostic value, particularly during weaning. Additional adjuncts include arterial pulse pressure, end-tidal CO₂ and waveform analysis. Phenotype oriented priorities, such as detection of differential hypoxemia, prevention of left ventricular distension or surveillance for limb ischemia, require tailored monitoring strategies. Artificial intelligence and machine learning represent future avenues for integrating multiparametric data into predictive models. Conclusions: No single modality can capture the hemodynamic complexity of V-A ECMO. Precision monitoring demands a dynamic, phenotype-specific and time-dependent approach that integrates systemic, cardiac, metabolic and microcirculatory variables. Such individualized strategies hold promise to optimize outcomes, reduce complications and align V-A ECMO management with the principles of precision medicine. Full article

Background/Objectives: Preoxygenation with 100% oxygen is commonly used but poses risks such as hyperoxia and atelectasis. Using 80% oxygen may reduce these effects but shortens duration of apnoea without desaturation (DAWD). This study compared preoxygenation efficiency between 80% and 100% oxygen and evaluated changes in the Oxygen Reserve Index™ (ORi™). Methods: Patients undergoing elective laparoscopic cholecystectomy were randomized to preoxygenation with 80% or 100% oxygen. Adequate preoxygenation was defined as a ≤10% difference between fraction of inspired oxygen and end-tidal oxygen (EtCO₂). The primary outcome was DAWD, the interval from apnoea onset to peripheral oxygen saturation (SpO₂) of 93%. Secondary outcomes included time to adequate preoxygenation and additional warning time from ORi™ zero to SpO₂ 97%. Results: Thirty patients were randomised to 80% (n = 15) or 100% oxygen (n = 15) oxygen groups. One patient in the 100% group was excluded due to spontaneous breathing before SpO₂ 93%, leaving 29 for DAWD analysis. DAWD was 345 ± 136 s (80%) and 430 ± 163 s (100%) with a mean difference of 86 s (p = 0.135). No significant differences were observed in tie to adequate preoxygenation or additional warning time. Conclusions: Preoxygenation with 80% oxygen resulted in a numerically shorter DAWD compared with 100% oxygen, without a significant difference in ORi™. These findings may suggest the potential feasibility of using 80% oxygen for preoxygenation. However, given the limited sample size and uncertain clinical relevance, further large-scale studies are warranted to clarify the safety and clinical implications of lower oxygen concentration during anaesthesia induction. Full article

Background: Perioperative Cardiac Arrest (POCA) is a rare but catastrophic event with persistently low survival rates. Existing prediction models often fail to capture the perioperative context or predict short-term outcomes. This study aimed to develop and internally validate the POTEC (Platelet count, Oxygen saturation, Time of cardiopulmonary resuscitation (CPR), Elective surgery, and initial end-tidal carbon dioxide (ETCO₂) Score, a simple clinical tool for predicting 24-h survival following perioperative CPR. Methods: We conducted a retrospective cohort study of adult patients (≥18 years) who experienced POCA during or within two hours after non-cardiac surgery under anesthesia at a tertiary university hospital between 2010 and 2023. Multivariable logistic regression was used to identify independent predictors of 24-h survival. The final model’s coefficients were used to construct the POTEC Score, which was internally validated using bootstrapping (1000 replications). Results: Of 321 eligible patients, 65 (20.25%) survived at 24-h. Five variables were independently associated with 24-h survival and included in the POTEC score: preoperative platelet count 100 × 10⁹/L, preoperative oxygen saturation of ≥90% on room air upon arrival in the operating room, CPR duration ≤30 min, elective surgery, and initial end-tidal CO₂ between 35 and 45 mmHg. The score demonstrated good discrimination (AuROC = 0.788, 95% CI: 0.73–0.85) and calibration (Hosmer–Lemeshow p = 0.535). A score of 4 points or higher was associated with significantly higher odds of 24-h survival (adjusted OR = 2.78, 95% CI: 2.05–3.79). Model optimism was minimal (0.009) after bootstrapping. Conclusions: The POTEC Score is a clinically practical tool for early risk stratification in patients undergoing perioperative CPR. Its integration into perioperative workflows may aid in timely decision-making and resource prioritization during critical postoperative care. Full article

Background/Objectives: The maintenance of cerebral blood flow (CBF) by managing blood pressure and brain cell activity and avoiding hypocapnia is important when administering anesthesia to patients with dementia. This study aimed to evaluate CBF during general anesthesia in elderly patients with severe dementia while maintaining their physiological parameters within an adequate range. Methods: The patients were anesthetized within a set range of parameters without affecting CBF (mean arterial pressure [MAP] > 50 mmHg; bispectral index [BIS] > 20; percutaneous arterial oxygen saturation [SpO₂] > 95%; end-tidal CO₂ [etCO₂] 35–40 mmHg). The normalized tissue hemoglobin index (nTHI), which reflects CBF, was measured using near-infrared spectroscopy. The parameters were compared between patients with severe dementia (n = 13) and those without cognitive impairment (n = 13). Results: There were no differences in patient background. A similar decline in MAP and BIS values was observed in both groups, but the values remained within the set range. The nTHI decreased significantly to 0.60 in the dementia group and to 0.79 in the non-dementia group after the start of the treatment (p ≤ 0.049). Even when the MAP, BIS, SpO₂, and etCO₂ values were maintained in their adequate ranges during general anesthesia, the nTHI decreased by 40% in the dementia group. Conclusions: These findings indicate that CBF greatly decreases in elderly patients with severe dementia during general anesthesia. Full article

Background: Achalasia is a primary esophageal motility disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absent peristalsis, which increases the risk of aspiration during anesthesia. Peroral endoscopic myotomy (POEM) is a minimally invasive therapeutic approach requiring tailored anesthetic management. This study aimed to evaluate perioperative anesthesia management during POEM, focusing on ventilation parameters, intraoperative hemodynamics, laboratory changes, and the incidence and severity of postoperative complications. Methods: A retrospective analysis was conducted on 51 patients who underwent POEM between June 2016 and April 2025. Demographic features, anesthesia techniques, intraoperative physiologic parameters, hematologic profiles, and postoperative complications were evaluated. Standard preoperative fasting protocols were implemented. Rapid sequence induction (RSI) with propofol and rocuronium was followed by endotracheal intubation. Desflurane was used for maintenance anesthesia, with ventilation settings adjusted to limit end-tidal carbon dioxide (ETCO₂) elevation. Results: The median age of patients was 48 years, with a slight female (52.9%) predominance. Most patients were American Society of Anesthesiologists (ASA) II (64.7%) or ASA III (35.3%) scores and had comorbid hypertension (31.4%) or diabetes (11.8%). The median anesthesia duration was 180 min, and the peak inspiratory pressure remained stable at 25 mmHg. Oxygen saturation (SpO₂) improved during the procedure, while ETCO₂ increased from baseline to 49 mmHg by the end. Blood pressure declined transiently but recovered intraoperatively. Hematologic analysis showed significant increases in white blood cell (WBC) and neutrophils and mild decreases in hemoglobin, hematocrit, and platelets. Early postoperative complications included subcutaneous emphysema (19.6%), minor bleeding (9.8%), and pneumoperitoneum (7.84%). Two patients required tube thoracostomy due to pneumothorax, but no patient developed a complication requiring surgical exploration. During a median follow-up of 546 days, no mortality was reported. Long-term complications were infrequent, with gastroesophageal reflux disease (GERD) (3.92%) and esophagitis (1.96%) being the most notable. Conclusions: POEM can be performed safely with appropriate anesthetic management. Despite significant physiologic changes during carbon dioxide (CO₂) insufflation, no life-threatening complications occurred, and the majority of adverse events were minor and self-limiting. Close intraoperative monitoring and interdisciplinary coordination contribute to favorable perioperative outcomes. Full article

To elucidate the changes in gas exchange across the life course, we estimated the age trajectories of O₂ saturation, CO₂ (as either end-tidal or serum bicarbonate), resting heart rate, and resting respiratory rate from age 2 yr onward in female and male patients separately. We utilized two sources’ data: electronic health records (EHR) representing ambulatory visits of approximately 53,000 individuals and sleep clinic polysomnogram (PSG) records representing an additional ~21,000. We used linear regression to estimate age-group-specific mean response levels for women and men. We compared estimated female–male differences between pre- and post-pubertal children and between pre- and post-menopausal periods among adults. Women between 15 and 45 years had higher O₂ saturation and lower serum bicarbonate levels or end-tidal CO₂ levels than men of similar ages. For O₂ saturation and for both measures of CO₂, the female–male difference was larger on average among adults at pre-menopausal ages than those at post-menopausal ages. Women had higher O₂ saturation throughout their lives than men; however, the difference disappeared in the elderly. Women between menarche and menopause had significantly lower end-tidal CO₂ and serum bicarbonate than men of similar ages. After menopause, however, women appeared to have higher mean levels of both end-tidal CO₂ and serum bicarbonate than men. Full article

Background/Objectives: Lung-protective ventilation (LPV) reduces postoperative pulmonary complications (PPCs) in obese patients. While the roles of low tidal volume and positive end-expiratory pressure (PEEP) in LPV have been established in patients with healthy lungs, the protective effect of alveolar recruitment strategies (ARSs) remains a subject of debate. This study aims to evaluate the benefit of ARSs in patients with low-to-moderate risk according to the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score undergoing gynecologic cancer surgery with LPV and low tidal volume intraoperatively. Methods: A total of 88 obese patients were evaluated in this study. They were divided into two groups as the non-ARS group (non-ARS) and the ARS group (ARS). Intraoperative hemodynamics, blood gas analyses, respiratory mechanics, mechanical ventilator parameters, and postoperative outcomes were compared in these obese patients. Results: A total of 40 obese patients undergoing major gynecological cancer surgery were included in this study. Although the non-ARS group presented with higher weight (p < 0.05), body mass indexes were similar to the ARS group. Intraoperative blood gas analysis revealed higher end-tidal carbon dioxide (etCO₂) levels in the non-ARS group during the T2 and T3 time intervals (p < 0.05). In the ARS group, peak inspiratory pressure (PIP) at T3 was lower, while drive pressures at T1 and T2 and dynamic compliance at T3 were higher (p < 0.05). Radiologic atelectasis scores were higher in the non-ARS group, indicating more atelectatic lung images (p < 0.05). PPC rates were similar across both groups. Conclusions: Although the ARS demonstrated positive effects on lung mechanics and radiologic atelectasis scores in major open gynecologic cancer surgeries, it did not effectively reduce postoperative pulmonary complications. Full article

Background/Objectives: Orthostatic intolerance is prevalent in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is caused by an abnormal reduction in cerebral blood flow (CBF). In healthy controls (HCs), CBF is regulated complexly, and cardiac output (CO) is an important determinant of CBF. A review in HC showed that a 30% reduction in CO results in a 10% reduction in CBF. In contrast, we showed in ME/CFS patients with a normal HR (HR) and blood pressure response during a tilt test that CO and CBF decreased to a similar extent. The relation between CO and CBF in ME/CFS patients with postural orthostatic tachycardia syndrome (POTS) is unknown. Therefore, the aim of this study is to assess the relation between CBF and CO, in ME/CFS patients with POTS. The methods used in this retrospective study analyze this relation in a large group of patients. We also analyzed the influence of clinical data. A total of 260 ME/CFS patients with POTS underwent tilt testing with measurements of HR, BP, CBF, CO, and end-tidal PCO₂. We measured CBF using extracranial Doppler flow velocity and vessel diameters obtained with a General Electric echo system, and suprasternal aortic flow velocities were measured using the same device. We recorded end-tidal PCO₂ using a Nonin Lifesense device. Results: End-tilt HR and the HR increase were significantly higher in the patients with a %CO reduction ≥ −15% than in the other group. End-tilt CO was higher and the %CO reduction was lower in patients with %CO reduction ≥ −15% than in the other group. CBF data (supine, end-tilt and the %CBF reduction) were not different between the two patient groups. The use of HR increases and %SV reductions were not as discriminative as the %CO reduction. Conclusions: In ME/CFS patients with POTS during tilt testing with measurements of both the CO and the CBF, two different patterns were observed: (1) appr. two-thirds of patients had an almost 1:1 relation between the %CBF reduction and the %CO reduction. (2) Appr. one-third of patients showed a limited reduction in CO together with a substantial increase in HR. In these patients, there was no relation between the CO and CBF reduction. These data suggest the presence of a hyperadrenergic response. Full article

Automated ventilator controllers have the potential to simplify oxygen and carbon dioxide management for trauma. In the pre-hospital or military medicine environment, trauma care can be required for prolonged periods by personnel with limited ventilator management training. As such, there is a need for closed-loop control systems that can adapt ventilator management to a complex, ever-changing medical environment. Here, we present a novel hardware-in-loop test platform for the independent troubleshooting and evaluation of oxygen and carbon dioxide automated ventilator management capabilities. The oxygen management system provides an analogue blood oxygen signal that is responsive to the fraction of inspired oxygen and the peak inspiratory pressure ventilator settings. A tested oxygenation controller successfully reached the target oxygen saturation within 5 min. The carbon dioxide removal system integrates with commercial ventilator technology and mimics carbon dioxide generation, lung compliance, and airway resistance while providing an end-tidal carbon dioxide level that is responsive to changes in the tidal volume and respiratory rate settings. A test mechanical ventilator controller was able to regulate EtCO₂ regardless of the starting value within 10 min. This highlights the system’s functionality and provides proof-of-concept demonstrations for how the hardware-in-loop test platforms can be used for evaluating closed-loop controller technologies. Full article