Position Statement of ISCCM Committee on Weaning from Mechanical Ventilator.

Background and purpose: Weaning from a mechanical ventilator is a milestone in the recovery of seriously ill patients in Intensive care. Failure to wean and re-intubation adversely affects the outcome. The method of mechanical ventilation (MV) varies between different ICUs and so does the practice of weaning. Therefore, updated guidelines based on contemporary literature are designed to guide intensivists in modern ICUs. This is the first ISCCM Consensus Statement on weaning complied by a committee on weaning. The recommendations are intended to be used by all the members of the ICU (Intensivists, Registrars, Nurses, and Respiratory Therapists). Methods: A Committee on weaning from MV, formed by the Indian Society of Critical Care Medicine (ISCCM) has formulated this statement on weaning from mechanical ventilators in intensive care units (ICUs) after a review of the literature. Literature was first circulated among expert committee members and allotted sections to each member. Sections of the statement written by sectional authors were peer-reviewed on multiple occasions through virtual meetings. After the final manuscript is accepted by all the committee members, it is submitted for peer review by central guideline committee of ISCCM. Once approved it has passed through review by the Editorial Board of IJCCM before it is published here as "ISCCM consensus statement on weaning from mechanical ventilator". As per the standard accepted for all its guidelines of ISCCM, we followed the modified grading of recommendations assessment, development and evaluation (GRADE) system to classify the quality of evidence and strength of recommendation. Cost-benefit, risk-benefit analysis, and feasibility of implementation in Indian ICUs are considered by the committee along with the strength of evidence. Type of ventilators and their modes, ICU staffing pattern, availability of critical care nurses, Respiratory therapists, and day vs night time staffing are aspects considered while recommending for or against any aspect of weaning. Result: This document makes recommendation on various aspects of weaning, namely, definition, timing, weaning criteria, method of weaning, diagnosis of failure to wean, defining difficult to wean, Use of NIV, HFOV as adjunct to weaning, role of tracheostomy in weaning, weaning in of long term ventilated patients, role of physiotherapy, mobilization in weaning, Role of nutrition in weaning, role of diaphragmatic ultrasound in weaning prediction etc. Out of 42 questions addressed; the committee provided 39 recommendations and refrained from 3 questions. Of these 39; 32 are based on evidence and 7 are based on expert opinion of the committee members. It provides 27 strong recommendations and 12 weak recommendations (suggestions). Conclusion: This guideline gives extensive review on weaning from mechanical ventilator and provides various recommendations on weaning from mechanical ventilator. Though all efforts are made to make is as updated as possible one needs to review any guideline periodically to keep it in line with upcoming concepts and standards. How to cite this article: Clerk AM, Shah RJ, Kothari J, Sodhi K, Vadi S, Bhattacharya PK, et al. Position Statement of ISCCM Committee on Weaning from Mechanical Ventilator. Indian J Crit Care Med 2024;28(S2):S233-S248.

Management of Potential Organ Donor: Indian Society of Critical Care Medicine-Position Statement.

This position statement is documented based on the input from all contributing coauthors from the Indian Society of Critical Care Medicine (ISCCM), following a comprehensive literature review and summary of current scientific evidence. Its objective is to provide the standard perspective for the management of potential organ/tissue donors after brain death (BD) in adults only, regardless of the availability of technology. This document should only be used for guidance only and is not a substitute for proper clinical decision making in particular circumstances of any case. Endorsement by the ISCCM does not imply that the statements given in the document are applicable in all or in a particular case; however, they may provide guidance for the users thus facilitating maximum organ availability from brain-dead patients. Thus, the care of potential brain-dead organ donors is "caring for multiple recipients." How to cite this article: Zirpe K, Pandit R, Gurav S, Mani RK, Prabhakar H, Clerk A, et al. Management of Potential Organ Donor: Indian Society of Critical Care Medicine-Position Statement. Indian J Crit Care Med 2024;28(S2):S249-278.

Unmasking of Agenesis of Right Pulmonary Artery with Unilateral Absence of Perfusion on Lung Scintigraphy.

We present a rare finding on lung ventilation-perfusion (V/Q) scintigraphy for a woman with longstanding dyspnea. CT of the chest showed volume loss on the right side, which raised concern about possible bronchiolitis obliterans or Swyer-James-MacLeod syndrome; however, the right pulmonary artery could not be visualized. A subsequent V/Q scan showed absence of perfusion and decreased ventilation to the entire right lung, consistent with agenesis of the right pulmonary artery. The patient's clinical course and imaging features mimicked Swyer-James-MacLeod syndrome, which usually presents with a matched perfusion defect in a single lung or lobe on V/Q scanning. This case highlights the importance of a multimodality imaging approach to achieve a diagnosis.

Oxygen Delivery Devices in Postoperative Patients: Proper Selection of Patients Matters!

How to cite this article: Bhattacharya D, Esquinas AM, Mandal M. Oxygen Delivery Devices in Postoperative Patients: Proper Selection of Patients Matters! Indian J Crit Care Med 2024;28(8):802.

Comparison of pSOFA with PRISM III and PIM 2 as Predictors of Outcome in a Tertiary Care Pediatric ICU: A Prospective Cross-sectional Study.

Aims and background: Severity scores are used to predict the outcome of children admitted to the intensive care unit. A descriptive score such as the pediatric sequential organ failure assessment (pSOFA) may be useful for prediction of outcome. This study was planned to compare the pSOFA score with these well-studied scores for prediction of mortality. Materials and methods: This prospective cross-sectional study was conducted at the pediatric intensive care units (PICU) of a tertiary care hospital. Children aged from 1 month to 12 years were enrolled sequentially. The pediatric index of mortality (PIM 2) score was calculated within 1 hour, and pediatric risk of mortality (PRISM) III and pSOFA scores were calculated within 24 hours of PICU admission. The pediatric sequential organ failure assessment score was recalculated after 72 hours. The primary outcome variable was hospital mortality, and secondary outcome variables were duration of PICU stay, need for mechanical ventilation, and occurrence of acute kidney injury (AKI). Appropriate statistical tests were used. Results: About 151 children with median (IQR) age of 36 (6, 84) months were enrolled. Mechanical ventilation was required in 87 (57.6%) children. Mortality was 21.2% at 28 days. The median (IQR) predicted mortality using PRISM III and PIM 2 score were 3.4 (1.5%, 11%) and 8.2 (3.1%, 16.6%) respectively. Area under ROC for prediction of mortality was highest for pSOFA 72 with a cut-off of 6.5 having sensitivity of 83.3% and specificity of 76.9%. Conclusion: The pSOFA score calculated at admission and at 72 hours had a better predictive ability for the PICU mortality compared to PRISM III and PIM 2 score. How to cite this article: Agrwal S, Saxena R, Jha M, Jhamb U, Pallavi. Comparison of pSOFA with PRISM III and PIM 2 as Predictors of Outcome in a Tertiary Care Pediatric ICU: A Prospective Cross-sectional Study. Indian J Crit Care Med 2024;28(8):796-801.

Reported impact and protective factors of the care partner role during persistent critical illness: a content analysis.

BACKGROUND: Patients with persistent critical illness experience prolonged multi-system morbidity, functional impairments, and chronic conditions. As a result, these patients have prolonged intensive care unit admissions. If discharged, they return home with long-term medical dependencies. Care partners take on a variety of physical, mental health, cognitive, and social roles to support the provision of care for these patients. There is limited evidence, however, of the impact of being a care partner for this patient population during hospitalization. METHODS: A qualitative descriptive study was conducted to explore the impact care provision on care partners for patients experiencing persistent critical illness. Patients who have or have had persistent critical illness and care partners were recruited from two inpatient units in a single community academic hospital in Toronto, Canada to participate in semi-structured interviews. Data was analyzed using a team-based inductive content analysis. RESULTS: Seven (43.8%) participants were patient survivors, and nine (56.3%) were care partners. Patients and care partners reported physical, socio-emotional, and social stress as impacts of care provision during persistent critical illness hospitalization. Care partners identified several protective strategies that they used to mitigate the impacts of care provision on them such as seeking external mental health support and boundary setting. Features of formalized and care partner programs were also identified and suggest that these programs can be protective of care partner values, mitigate feelings of helplessness and stress, and may improve relationships between the family members who are in the care partner role and the healthcare team. CONCLUSIONS: This study identified physical, socio-emotional, and social stress related impacts of care provision on care partners of patients with persistent critical illness during hospitalization. Additionally, this study identified protective factors initiated by care partners to mitigate the reported stresses of the role, as well as protective features of a care partner program. The results provide a better understanding supportive features of care partner programs that are specific to the experiences and needs of persistent critical illness and add to the growing body of evidence about how to provide equitable access to care during and post hospitalization.

Machine learning-based risk prediction model construction of difficult weaning in ICU patients with mechanical ventilation.

In intensive care unit (ICU) patients undergoing mechanical ventilation (MV), the occurrence of difficult weaning contributes to increased ventilator-related complications, prolonged hospitalization duration, and a significant rise in healthcare costs. Therefore, early identification of influencing factors and prediction of patients at risk of difficult weaning can facilitate early intervention and preventive measures. This study aimed to strengthen airway management for ICU patients by constructing a risk prediction model with comprehensive and individualized offline programs based on machine learning techniques. This study involved the collection of data from 487 patients undergoing MV in the ICU, with a total of 36 variables recorded. The dataset was divided into a training set (70% of the data) and a test set (30% of the data). Five machine learning models, namely logistic regression, random forest, support vector machine, light gradient boosting machine, and extreme gradient boosting, were compared to predict the risk of difficult weaning in ICU patients with MV. Significant influencing factors were identified based on the results of these models, and a risk prediction model for ICU patients with MV was established. When evaluating the models using AUC (Area under the Curve of ROC) and Accuracy as performance metrics, the Random Forest algorithm exhibited the best performance among the five machine learning algorithms. The area under the operating characteristic curve for the subjects was 0.805, with an accuracy of 0.748, recall (0.888), specificity (0.767) and F1 score (0.825). This study successfully developed a risk prediction model for ICU patients with MV using a machine learning algorithm. The Random Forest algorithm demonstrated the highest prediction performance. These findings can assist clinicians in accurately assessing the risk of difficult weaning in patients and formulating effective individualized treatment plans. Ultimately, this can help reduce the risk of difficult weaning and improve the quality of life for patients.

Effect of Sitting Baduanjin exercise on early rehabilitation of sepsis patients with non-invasive ventilation : a randomized controlled trial.

BACKGROUND: For patients with sepsis receiving non-invasive ventilation (NIV), early rehabilitation is crucial. The Sitting Baduanjin (SBE) is an efficient early rehabilitation exercise suitable for bed patients. There is no consensus about the effect of SBE on the early rehabilitation of septic patients with NIV. This study focused on how the SBE affected the early rehabilitation of sepsis patients with NIV. METHODS: 96 sepsis patients with NIV were randomly assigned to either an Baduanjin group that received the SBE based on the routine rehabilitation exercise (n = 48) or a control group (n = 48) that received routine rehabilitation exercise. The primary outcome was the Medical Research Council(MRC)score, and the Barthel Index score, the duration of NIV, length of ICU stay, length of total stay, hospitalization expense as secondary outcomes. RESULTS: A total of 245 sepsis patients were screened, with 96 randomly assigned. The study was completed by 90 patients out of the 96 participants.Results revealed that the MRC score increased in both groups, but the improvement of muscle strength in Baduanjin group was more obvious, with statistical significance (p < 0.001).There was statistically significantly difference between the two groups in Barthel Index at the day of transfer out of ICU(P = 0.028).The patients in the Baduanjin group had an average reduction of 24.09 h in the duration of NIV and 3.35 days in total length of hospital stay compared with the control group (p < 0.05).Of note, the Baduanjin group had significantly reduction the total hospitalization expense. No serious adverse events occurred during the intervention period. CONCLUSIONS: In patients with sepsis, the SBE appears to improve muscle strength and activities of daily living (ADL), and lowed the duration of NIV, the length of the total stay, and the hospitalization expense. TRIAL REGISTRATION: The study registered on the Chinese Clinical Trial Registry ( www.chictr.org.cn ), Clinical Trials identifier ChiCTR1800015011 (28/02/2018).

Minimally invasive technique facilitates early extubation after cardiac surgery: a single-center retrospective study.

BACKGROUND: Postoperative time to extubation plays a role in prognosis after heart valve surgery; however, its exact impact has not been clarified. This study compared the postoperative outcomes of minimally invasive surgery and conventional sternotomy, focusing on early extubation and factors influencing prolonged mechanical ventilation. METHODS: Data from 744 patients who underwent heart valve surgery at the Zhejiang Provincial People's Hospital between August 2019 and June 2022 were retrospectively analyzed. The outcomes in patients who underwent conventional median sternotomy (MS) and minimally invasive (MI) video-assisted thoracoscopic surgery were compared using inverse probability of treatment weighting (IPTW) and Kaplan-Meier curves. Clinical data, including surgical data, postoperative cardiac function, postoperative complications, and intensive care monitoring data, were analyzed. RESULTS: After propensity score matching and IPTW, 196 cases of conventional MS were compared with 196 cases of MI video-assisted thoracoscopic surgery. Compared to patients in the conventional MS group, those in the MI video-assisted thoracoscopic surgery group in the matched cohort had a higher early postoperative extubation rate (P < 0.01), reduced incidence of postoperative pleural effusion (P < 0.05), significantly shorter length of stay in the intensive care unit (P < 0.01), shorter overall length of hospital stay (P < 0.01), and lower total cost of hospitalization (P < 0.01). CONCLUSIONS: Successful early tracheal extubation is important for the intensive care management of patients after heart valve surgery. The advantages of MI video-assisted thoracoscopic surgery over conventional MS include significant reductions in the duration of use of mechanical ventilation support, reduced length of intensive care unit stay, reduced total length of hospitalization, and a favorable patient recovery rate.

A nationwide survey on the management of neonatal respiratory distress syndrome: insights from the MUNICH survey in 394 Chinese hospitals.

BACKGROUND: At present, preterm infants with respiratory distress syndrome (RDS) in China present higher mortality and morbidity rates than those in high-income countries. The aim of this nationwide survey was to assess the clinical management of RDS in China. METHODS: A nationwide cross-sectional survey to assess adherence to RDS management recommendations was performed. One neonatologist per hospital was randomly selected. The primary outcome was the key care of RDS management. RESULTS: Among the 394 participating hospitals, 88·3% were birthing centres. The number of doctors and nurses per bed were 0·27 and 0·72, respectively. Antenatal corticosteroids (any dose) were administered to 90% of the women at risk of preterm birth at < 34 weeks of gestation (90·0% inborn vs. 50·0% outborn, p < 0·001). The median fraction of inspired oxygen (FiO2) for initial resuscitation was 0·30 for babies born at ≤ 32 weeks of gestation and 0·25 for those born at > 32 weeks. T-piece resuscitators were available in 77·8% of delivery rooms (DRs) (tertiary hospitals: 82·5% vs. secondary hospitals: 63·0%, p < 0·001). Surfactant was used in 51·6% of the DRs. Less invasive surfactant administration (LISA) was used in 49·7% of the hospitals (tertiary hospitals: 55·3% vs. secondary hospitals: 31·5%, p < 0·001). Primary non-invasive ventilation was initiated in approximately 80·0% of the patients. High-frequency oscillation ventilation was primarily reserved for rescue after conventional mechanical ventilation (MV) failure. Caffeine was routinely used during MV in 59·1% of the hospitals. Bedside lung ultrasonography was performed in 54·3% of the health facilities (tertiary hospitals: 61·6% vs. secondary hospitals: 30·4%, p < 0·001). Qualified breast milk banks and Family Integrated Care (FICare) were present in 30·2% and 63·7% of the hospitals, respectively. CONCLUSIONS: Significant disparities in resource availability and guidelines adherence were evident across hospitals. Future strategies should address DR facilities and medication access, technical training, staff allocation, and ancillary facility development for a better management of RDS patients in China.

Impact of COVID-19 on Ventilation-Perfusion (V/Q) Scans: A Comparative Analysis of Pre-COVID-19 Era V/Q Scans and Post-COVID-19 Era Perfusion Scans.

Introduction The COVID-19 pandemic has profoundly impacted medical practices, including nuclear medicine. To minimize aerosol transmission risks, lung perfusion scintigraphy was preferred over traditional ventilation-perfusion (V/Q) scintigraphy during the pandemic. This study compares lung perfusion scans performed during COVID-19 with V/Q scans from the pre-COVID era. After reviewing this study, the reader will learn about V/Q scintigraphy and lung perfusion. Methods This retrospective observational study, conducted from December 2018 to July 2021, involved 868 patients - 511 in the pre-COVID era and 357 in the post-COVID era - at a single tertiary care center. The pretest probability of pulmonary embolism (PE) was determined using Wells' criteria, and data including demographics, clinical findings, and diagnostic test results (V/Q or lung perfusion scintigraphy) were collected. Results A 30% decline in lung scans was observed during the pandemic. In the pre-COVID era, 68.3% of scans had low, 27.8% had intermediate, and 3.9% had high probability for PE. During the pandemic, perfusion-only scans showed 57.3% low, 32.9% indeterminate, and 9.8% high probability for PE. Among COVID-19-positive patients, 48.9% had intermediate, and 11.1% had high probability scans. The rise in indeterminate and high-probability scans during the pandemic is attributed to COVID-19-related lung changes and hypercoagulability. Conclusion The perfusion component of lung scans is typically sufficient for evaluating acute PE. Omitting the ventilation part of the V/Q scan had minimal impact, with only a 5.1% increase in indeterminate/non-diagnostic scans using perfusion-only modified Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) criteria during the post-COVID-19 era, likely due to underlying lung parenchymal involvement in COVID-19 patients. Additionally, there was a 5.9% rise in high-probability scans, attributed to the hypercoagulability and vascular complications associated with COVID-19.

Resolvin E1 and Inhibition of BLT2 Signaling Attenuate the Inflammatory Response and Improve One-Lung Ventilation-Induced Lung Injury.

INTRODUCTION: One-lung ventilation (OLV) is a prevalently used technique to sustain intraoperative pulmonary function. Resolvin E1 (RvE1), a specialized pro-resolving lipid mediator, accelerates the resolution of inflammation in the lungs. However, its therapeutic effects on OLV-induced lung injury remain unclear. METHODS: We initially developed an OLV rat model and treated it with RvE1. Subsequently, we assessed the wet/dry ratio of the lung tissue, performed hematoxylin and eosin staining, and calculated the ratio of polymorphonuclear cells to white blood cells in the bronchoalveolar lavage fluid. Additionally, we assessed apoptosis, inflammatory factor levels, and lung permeability in the rat lung tissues in the RvE1 treated and untreated groups and explored the molecular mechanisms mediated by RvE1. RESULTS: Our results indicated that RvE1 alleviated lung injury and inflammation and improved lung tissue apoptosis and permeability in OLV rats. Moreover, RvE1 suppressed the expression of the BLT1/2 signaling pathway and its ligands. The use of BLT2 and BLT1 inhibitors (LY255283 and U-75302, respectively) enhanced RvE1's anti-inflammatory effects and reduced lung injury. Furthermore, synergistic treatment with the BLT2 inhibitor and RvE1 provided grater benefits by more effectively inhibiting the NF-kB, p38 MAPK, and ERK pathways. DISCUSSION: RvE1 and the inhibition of BLT2 signalling reduce the inflammatory response and mitigate OLV-induced lung injury. These findings suggest a novel therapeutic pathway for managing OLV-related complications.

Early sleep apnea treatment in stroke (eSATIS) - a multicentre, randomised controlled, rater-blinded, clinical trial: The association of post-stroke cognition with sleep-disordered breathing and its treatment.

Sleep-disordered breathing (SDB) is linked to cognitive dysfunction. Although SDB is common in stroke patients, the impact of SDB and its early treatment on cognitive functioning after stroke remains poorly investigated. Therefore, we explored the association between SDB and post-stroke cognitive functioning, including the impact of early SDB treatment with adaptive servo-ventilation (ASV) on cognitive recovery from acute event to 3 months post-stroke. We used data from two studies, which included ischaemic stroke patients (n = 131) and no-stroke controls (n = 37) without SDB (apnea-hypopnea index, AHI <5/h) and with SDB (AHI≥20/h). Cognitive functioning was assessed within 7 days and 3 months post-stroke in stroke patients, or at study inclusion in no-stroke control group, respectively. Stroke patients with SDB were randomized to ASV treatment (ASV+) or usual care (ASV-). Linear regression adjusted for main confounders assessed the impact of SDB and its treatment on cognitive recovery. The intention-to-treat analysis did not show significant associations of SDB ASV+ (n = 30) versus SDB ASV- (n = 29) with cognitive recovery. In an exploratory subanalysis, compliant SDB ASV+ (n = 14) versus SDB ASV- showed improvements with ASV in visual memory and cognitive flexibility. Combining the stroke and non-stroke datasets, SDB (n = 85) versus no-SDB (n = 83) was associated with deficits in visual memory and response inhibition independently of stroke. SDB ASV- versus no-SDB (n = 51) was associated with less improvement in visual memory. There was no substantial evidence for benefits of intention-to-treat ASV on cognitive recovery. Exploratory analysis indicated that compliant ASV treatment could benefit visual memory and cognitive flexibility, whereas untreated SDB could contribute to a poor recovery of visual memory.

Descending motor drive does not interact with muscle metaboreflex for ventilation regulation during rhythmic exercise in healthy humans.

The muscle metaboreflex effect on pulmonary ventilation (V̇E) regulation is more apparent during rhythmic exercise than rest, possibly because this reflex interacts with other mechanisms regulating V̇E during voluntary contractions, such as central command. Therefore, we tested whether one part of central command, the descending component of motor execution (i.e., descending motor drive), and the muscle metaboreflex interact synergistically to regulate V̇E. Thirteen healthy adults (9 men) completed four experiments in random order under isocapnia. The muscle metaboreflex was activated by rhythmic handgrip exercise at 60% maximal voluntary contraction (MVC) force with the dominant hand. Then, the muscle metaboreflex remained active during a 4-minute recovery period via post-exercise circulatory occlusion (PECO), or it was inactivated, maintaining free blood flow to the dominant upper limb. During the last 2-minutes of the handgrip exercise recovery, participants either performed rhythmic voluntary plantar flexion with the dominant leg at 30% MVC torque to generate descending motor drive or the dominant leg's calf muscles were involuntarily activated by electrical stimulation at a similar torque level (i.e., without descending motor drive). V̇E increased to a similar level during handgrip exercise in all conditions (≈22 L/min, P = 0.364). PECO maintained V̇E elevated above recovery with free blood flow (≈17 L/min vs. ≈13 L/min, P = 0.009). However, voluntary and involuntary plantar flexion with or without PECO evoked similar V̇E responses (∆ ≈ 4 L/min, P = 0.311). Therefore, an interaction between descending motor drive and muscle metaboreflex is not ubiquitous for V̇E regulation during rhythmic exercise.

Effect of body position during weaning from total liquid ventilation in piglets.

OBJECTIVE: To determine if change in body position improves oxygen requirements and respiratory mechanics during the transition from total liquid ventilation (TLV) to gas ventilation. METHODS: Fourteen piglets underwent TLV, followed by a 2-hour weaning period under conventional gas ventilation. Subjects were randomized to the experimental group (Rotating - R), that was in prone position between the 10th and 30th minute of weaning, or to the static control group (Supine - S). RESULTS: Oxygenation index was lower in the R group at 30 minutes in prone position than that in the S group (1.9 [1.6; 2.8] vs 3.5 [3.1; 5.1], p = 0.001). This difference disappeared when subjects resumed the supine position (4.2 [3.8; 4.7] and 4.7 [3.8; 5.4], p = 0.4, for the R and S groups, respectively). The change in body position did not affect respiratory system compliance or inspiratory capacity. CONCLUSION: Prone position improved oxygenation during weaning from TLV. The effect disappeared once piglets returned to the supine position.

Loss of endogenous circadian clock function in mice alters respiratory cycle timing in a time of day- and sex-specific manner.

Resting breathing and ventilatory chemoreflexes are regulated in a 24-hr manner by the endogenous circadian clock. However, it is unclear how circadian biology influences different phases of the breath-to-breath respiratory cycle which are predominantly controlled by pontomedullary regions of the brainstem. Here, we performed whole-body plethysmography during quiet wakefulness in young adult male and female mice lacking the core clock gene Brain and Muscle Arnt-like 1 (BMAL1) to determine the extent to which the molecular clock affects respiratory cycle timing and ventilatory airflow mechanics. Breath waveform analysis revealed that male BMAL1 knockout (KO) mice exhibit time of day-specific differences in inspiratory and expiratory times, total cycle length, end inspiratory pause, relaxation time, and respiratory rate compared to wild-type littermates. Notably, changes in respiratory pattern were not observed in female BMAL1 KO mice when compared to wild-type females. Additionally, BMAL1 deficiency did not disrupt overall minute ventilation or peak airflow in either sex, suggesting total ventilatory function during quiet wakefulness is preserved. Taken together, these findings indicate that genetic disruption of the circadian clock in mice elicits sex-specific changes in respiratory cycle timing.

Cardiopulmonary adaptations of a diving marine mammal, the bottlenose dolphin: Physiology during anesthesia.

Diving marine mammals are a diverse group of semi- to completely aquatic species. Some species are targets of conservation and rehabilitation efforts; other populations are permanently housed under human care and may contribute to clinical and biomedical investigations. Veterinary medical care for species under human care, at times, may necessitate the use of general anesthesia for diagnostic and surgical indications. However, the unique physiologic and anatomic adaptations of one representative diving marine mammal, the bottlenose dolphin, present several challenges in providing ventilatory and cardiovascular support to maintain adequate organ perfusion under general anesthesia. The goal of this review is to highlight the unique cardiopulmonary adaptations of the completely aquatic bottlenose dolphin (Tursiops truncatus), and to identify knowledge gaps in our understanding of how those adaptations influence their physiology and pose potential challenges for sedation and anesthesia of these mammals.

Mitigating flood risk and environmental change in show caves: Key challenges in the management of the Las Güixas cave (Pyrenees, Spain).

A successful management of a show cave requires knowledge of cave dynamics and the main risk factors. Show caves close to the water table are prone to sporadic flooding, which can threaten visitor safety and result in severe economic losses. Las Güixas cave, located in the Collarada Massif (Pyrenees - Spain), is representative of a show cave close to the water table that is exposed to energetic flash floods. We conducted a five-year comprehensive cave monitoring study including air temperature, relative humidity, CO2 concentration and water level. Additionally, we measured outside temperature and precipitation. Air temperature variations and ventilation dynamics occurring in most of the cave are controlled by the outside temperature due to entrances at different elevations, except in a non-ventilated area showing more stable hygrothermal characteristics and higher summer values of CO2 concentration. The study also identifies distinct CO2 sources related to the degassing of water and visitors' breathing. Monitoring data show that the rapid degassing of cave water during flooding may increase subsurface CO2 concentrations to levels well above the exposure limits. However, the strong ventilation observed inside the cave rapidly removes CO2 peaks produced by flooding and limits the anthropic CO2 rise to ∼100 ppm. Hydrograph analysis revealed a response time of 8-12 h in the cave water levels to external rainfall/snowmelt events. Based on these results, a flood alarm system supports sustainable show cave management and the number of visitors is optimized according to the environmental conditions of the cave. This monitoring study has greatly contributed to our knowledge of cave dynamics, which can serve to improve flood risk management and increase the profitability of the show cave. Nonetheless, extreme floods remain a significant concern for potential economic losses in the future, considering current climate change scenarios. Hydrological studies together with a long-term monitoring will allow evaluating the impact of future changes in climate and environmental parameters.

Emergency medicine updates: Endotracheal intubation.

INTRODUCTION: Airway management including endotracheal intubation (ETI) is a key skill for emergency clinicians. Therefore, it is important for emergency clinicians to be aware of the current evidence regarding the identification and management of patients requiring ETI. OBJECTIVE: This paper evaluates key evidence-based updates concerning ETI for the emergency clinician. DISCUSSION: ETI is commonly performed in the emergency department (ED) setting but has many nuanced components. There are several tools that have been used to predict a difficult airway which incorporate anatomic and physiologic features. While helpful, these tools should not be used in isolation. Preoxygenation and apneic oxygenation are recommended to reduce the risk of desaturation and patient decompensation, particularly with noninvasive ventilation in critically ill patients. Induction and neuromuscular blocking medications should be tailored to the clinical scenario. Video laryngoscopy is superior to direct laryngoscopy among novice users, while both techniques are reasonable among more experienced clinicians. Recent literature suggests using a bougie during the first attempt. Point-of-care ultrasound is helpful for confirming correct placement and depth of the endotracheal tube. CONCLUSIONS: An understanding of literature updates can improve the ED care of patients requiring emergent intubation.