Usefulness of an Ultrasound-guided Prehospital Care for SCUBA Diving Accidents.

The incidence of diving accidents is increasing. Point-of-care ultrasound is the only imaging tool available in the field for the military physician who practices in isolated conditions. While ultrasound is integrated in the pre-hospital evaluation protocols of severe trauma patients, few applications are described for diving accident victims. Through a clinical case, we propose an algorithm of ultrasound triage for diving accidents with pulmonary symptoms. Point-of-care ultrasound makes it possible to avoid a risky transfer, by supporting a diagnosis and the treatment on the spot, to rule out contraindications to recompression, and to detect and monitor the treatment of high-risk complications such as the capillary leak syndrome.

Use of Intranasal Analgesia in French Armed Forces: A Cross-Sectional Survey.

BACKGROUND: Pain management is essential in military medicine, particularly in Tactical Combat Casualty Care (TCCC) during deployments in remote and austere settings. The few previously published studies on intranasal analgesia (INA) focused only on the efficacy and onset of action of the medications used (ketamine, sufentanil, and fentanyl). Side-effects were rarely reported. The aim of our study was to evaluate the use of intranasal analgesia by French military physicians. METHODS: We carried out a multicentric survey between 15 January and 14 April 2020. The survey population included all French military physicians in primary-care centers (n = 727) or emergency departments (n = 55) regardless of being stationed in mainland France or French overseas departments and territories. RESULTS: We collected 259 responses (33% responsiveness rate), of which 201 (77.6%) physicians reported being familiar with INA. However, regarding its use, of the 256 physicians with completed surveys, only 47 (18.3%) had already administered it. Emergency medicine physicians supporting highly operational units (e.g., Special Forces) were more familiar with this route of administration and used it more frequently. Ketamine was the most common medication used (n = 32; 57.1%). Finally, 234 (90%) respondents expressed an interest in further education on INA. CONCLUSION: Although a majority of French military physicians who replied to the survey were familiar with INA, few used it in practice. This route of administration seems to be a promising medication for remote and austere environments. Specific training should, therefore, be recommended to spread and standardize its use.

Duret Brainstem Hemorrhage After Transtentorial Descending Brain Herniation: A Systematic Review and Meta-Analysis.

BACKGROUND: Historically, the occurrence of hemorrhage in the brainstem after an episode of supratentorial intracranial hypertension was described by Henri Duret in 1878. Nevertheless, to date the eponym Duret brainstem hemorrhage (DBH) lacks systematic evidence regarding its epidemiology, pathophysiology, clinical and radiologic presentation, and outcome. METHODS: We conducted a systematic literature review and meta-analysis using the Medline database from inception to 2022 looking for English-language articles concerning DBH, in accordance with the PRISMA guidelines. RESULTS: The research yielded 28 articles for 32 patients (mean age, 50 years; male/female ratio, 3:1). Of patients, 41% had head trauma causing 63% of subdural hematoma, responsible for coma in 78% and mydriasis in 69%. DBH appeared on the emergency imaging in 41% and on delayed imaging in 56%. DBH was located in the midbrain in 41% of the patients, and in the upper middle pons in 56%. DBH was caused by sudden downward displacement of the upper brainstem secondary to supratentorial intracranial hypertension (91%), intracranial hypotension (6%), or mechanical traction (3%). Such downward displacement caused the rupture of basilar artery perforators. Brainstem focal symptoms (P = 0.003) and decompressive craniectomy (P = 0.164) were potential favorable prognostic factors, whereas an age >50 years showed a trend toward a poor prognosis (P = 0.0731). CONCLUSIONS: Unlike its historical description, DBH appears as a focal hematoma in the upper brainstem caused by the rupture of anteromedial basilar artery perforators after sudden downward displacement of the brainstem, regardless of its cause.

Incidence of Burnout Syndrome among Anesthesiologists and Intensivists in France: The REPAR Study.

BACKGROUND: Burnout syndrome (BOS) impacts health workers and has become a real public health issue. The primary objective of this observational study was to re-evaluate the incidence of BOS among anesthesiologists and intensivists (AI) in France, ten years after the SESMAT study, a French Physician Health Survey carried out among burnout salaried AI. The secondary objective was to investigate risks factors. METHODS: The REPAR survey is an observational study carried in France among AI, residents, and seniors, whatever their main mode of practice, in the framework of a self-questionnaire distributed on the Internet from 11 April 2018 to 1 July 2018. BOS was assessed using the Copenhagen Burnout Inventory (CBI). A score above 50% on two of the dimensions (personal burnout and work-related burnout) indicated BOS, as a main criterion. In order to investigate risks factors, questions were about sociodemographic characteristics, professional and extraprofessional environments, personality and mood using the Major Depression Inventory (MDI). A significance threshold of p < 0.05 was retained. RESULTS: Among 1519 questionnaires received, 1500 completed questionnaires were analyzed. There were 775 men (52%) and 721 women (48%), aged 23 to 74 years. Among those, 24% suffered from BOS, 9% showed depressive symptoms (MDI > 25) and 35% were considering changing jobs or stopping their studies. There was no significant difference with the SESMAT study for the general BOS score. After multivariate analysis, 12 variables were significantly associated with the main criterion. CONCLUSIONS: Ten years after the SESMAT study, the incidence of BOS in AI has not decreased in the largest cohort of AI studied to date in France.

Symptomatic or asymptomatic SAR-CoV-2 positive divers should be medically evaluated before returning to scuba diving.

Introduction: In order to allow the resumption of diving activities after a COVID-19 infection, French military divers are required to undergo a medical fitness to dive (FTD) assessment. We present here the results of this medical evaluation performed 1 month after the infection. Methods: We retrospectively analyzed between April 2020 and February 2021 200 records of divers suspected of COVID-19 contamination. Data collected included physical examination, ECG, blood biochemistry, chest CT scan and spirometry. Results: 145 PCR-positive subjects were included, representing 8.5% of the total population of French military divers. Two divers were hospitalized, one for pericarditis and the other for non-hypoxemic pneumonia. For the other 143 divers, physical examination, electrocardiogram and blood biology showed no abnormalities. However 5 divers (3.4%) had persistent subjective symptoms including fatigability, exertional dyspnea, dysesthesias and anosmia. 41 subjects (29%) had significant decreases in forced expiratory flows at 25-75% and 50% on spirometry (n = 20) or bilateral ground-glass opacities on chest CT scan (n = 24). Only 3 subjects were affected on both spirometry and chest CT. 45% of these abnormalities were found in subjects who were initially asymptomatic or had non-respiratory symptoms. In case of abnormalities, normalization was obtained within 3 months. The median time to return to diving was 45 days (IQR 30, 64). Conclusion: Our study confirms the need for standardized follow-up in all divers after COVID-19 infection and for maintaining a rest period before resuming diving activities.

The Kernohan-Woltman Notch Phenomenon : A Systematic Review of Clinical and Radiologic Presentation, Surgical Management, and Functional Prognosis.

The Kernohan-Woltman notch phenomenon (KWNP) refers to an intracranial lesion causing massive side-to-side mass effect which leads to compression of the contralateral cerebral peduncle against the free edge of the cerebellar tentorium. Diagnosis is based on "paradoxical" motor deficit ipsilateral to the lesion associated with radiologic evidence of damage to the contralateral cerebral peduncle. To date, there is scarce evidence regarding KWNP associated neuroimaging patterns and motor function prognostic factors. A systematic review was conducted on Medline database from inception to July 2021 looking for English-language articles concerning KWNP, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The research yielded 45 articles for a total of 51 patients. The mean age was 40.7 years-old and the male/female sex ratio was 2/1. 63% of the patients (32/51) suffered from head trauma with a majority of acute subdural hematomas (57%, 29/51). 57% (29/51) of the patients were in the coma upon admission and 47% (24/51) presented pupil anomalies. KWNP presented the neuroimaging features of compression ischemic stroke located in the contralateral cerebral peduncle, with edema in the surrounding structures and sometimes compression stroke of the cerebral arteries passing nearby. 45% of the patients (23/51) presented a good motor functional outcome; nevertheless, no predisposing factor was identified. A Glasgow coma scale (GCS) of more than 3 showed a trend (p=0.1065) toward a better motor functional outcome. The KWNP is a regional compression syndrome oftentimes caused by sudden and massive uncal herniation and leading to contralateral cerebral peduncle ischemia. Even though patients suffering from KWNP usually present a good overall recovery, patients with a GCS of 3 may present a worse motor functional outcome. In order to better understand this syndrome, future studies will have to focus on more personalized criteria such as individual variation of tentorial notch width.

Lung-Dependent Areas Collapse, Monitored by Electrical Impedance Tomography, May Predict the Oxygenation Response to Prone Ventilation in COVID-19 Acute Respiratory Distress Syndrome.

OBJECTIVES: ICUs have had to deal with a large number of patients with acute respiratory distress syndrome COVID-19, a significant number of whom received prone ventilation, which is a substantial consumer of care time. The selection of patients that we have to ventilate in prone position seems interesting. We evaluate the correlation between the percentage of collapsed dependent lung areas in the supine position, monitoring by electrical impedance tomography and the oxygenation response (change in Pao2/Fio2 ratio) to prone position. DESIGN: An observational prospective study. SETTING: From October 21, 2020, to 30 March 30, 2021. At the Sainte Anne military teaching Hospital and the Timone University Hospital. PATIENTS: Fifty consecutive patients admitted in our ICUs, with COVID-19 acute respiratory distress syndrome and required mechanical, were included. Twenty-four (48%) received prone ventilation. Fifty-eight prone sessions were investigated. INTERVENTIONS: An electrical impedance tomography recording was made in supine position, daily and repeated just before and just after the prone session. The daily dependent area collapse was calculated in relation to the previous electrical impedance tomography recording. Prone ventilation response was defined as a Pao2/Fio2 ratio improvement greater than 20%. MEASUREMENT AND MAIN RESULTS: The main outcome was the correlation between dependent area collapse and the oxygenation response to prone ventilation. Dependent area collapse was correlated with oxygenation response to prone ventilation (R2 = 0.49) and had a satisfactory prediction accuracy of prone response with an area under the curve of 0.94 (95% CI, 0.87-1.00; p < 0.001). Best Youden index was obtained for a dependent area collapse greater than 13.5 %. Sensitivity of 92% (95% CI, 78-97), a specificity of 91% (95% CI, 72-97), a positive predictive value of 94% (95% CI, 88-100), a negative predictive value of 87% (95% CI, 78-96), and a diagnostic accuracy of 91% (95% CI, 84-98). CONCLUSIONS: Dependent lung areas collapse (> 13.5%), monitored by electrical impedance tomography, has an excellent positive predictive value (94%) of improved oxygenation during prone ventilation.

Long-term surgical oncological and functional outcome of large petroclival and cerebellopontine angle epidermoid cysts: a multicenter study.

Cranial nerve (CN) disorders are the foremost symptoms in cerebellopontine angle (CPA) and petroclival area (PCA) epidermoid cysts (EC).The aim of this work was to  assess the long-term surgical results on CN function and tumor control in these patients. We performed a retrospective cohort study about 56 consecutive patients operated on for a CPA or PCA EC between January 2001 and July 2019 in six participating French cranial base referral centers. Sixteen patients (29%) presented a PCA EC and 40 a CPA EC (71%). The median clinical and radiological follow-up was 46 months (range 0-409). Preoperative CN disorders were present in 84% of patients (n = 47), 72% of them experienced CN deficits improvement at the last follow-up consultation (n = 34): 60% of cochlear and vestibular deficits (n = 9/15 in both groups), 67% of trigeminal neuralgia (n = 10/15), 53% of trigeminal hypoesthesia (n = 8/15), 44% of lower cranial nerve disorders (n = 4/9), 38% of facial nerve deficits (n = 5/8) and 43% of oculomotor deficits (n = 3/7) improved or were cured after surgery. New postoperative CN deficits occurred in 48% of patients (n = 27). Most of them resolved at the last follow-up, except for cochlear deficits which improved in only 14% of cases (n = 1/7). Twenty-six patients (46%) showed evidence of tumor progression after a median duration of 63 months (range 7-210). The extent of resection, tumor location, and tumor size was not associated with the occurrence of new postoperative CN deficit or tumor progression. A functional nerve-sparing resection of posterior fossa EC is an effective strategy to optimize the results on preexisting CN deficits and reduce the risk of permanent de novo deficits.

SARS Cov2 outbreak management on a landing helicopter dock: An observational retrospective study.

OBJECTIVES: Even though SARS Cov2 outbreak management has been well-described, scant information is available in military settings. We aimed to describe a SARS Cov2 outbreak and its management on the Dixmude, a French landing helicopter dock. PATIENTS AND METHODS: We performed an observational retrospective and monocentric study in a ship. Role 1 was reinforced by additional roles 1 and 2. Our analysis included all infected crew personnel. We described demographic data, outbreak course, and biological samples including Covid-19 diagnosis. All infected patients were monitored for 10 days. RESULTS: Between February 16th 2021 and March 12th 2021, 54 patients (10% of the entire crew) were included. No patient had previously been vaccinated against SARS Cov2. The global mission was maintained. The crew members were healthy, male, and young (median age 28 years) with no medical history. Ranks of every status were concerned. Covid-19 disease was mainly diagnosed by real-time reverse-transcriptase polymerase chain reaction (rt-PCR). Thirty-two patients (59%) were symptomatic, four (8%) were presymptomatic and 18 (33%) remained asymptomatic. CONCLUSIONS: The present work describes specific SARS Cov2 outbreak management in an austere military environment. Early individual and global measures were set and implemented on board.

Is routine gleno-humeral exploration a risk factor for adhesive capsulitis after arthroscopic removal of rotator cuff calcifications? A comparative retrospective study in 340 cases.

BACKGROUND: Arthroscopic surgery has earned its place as the reference standard treatment for rotator cuff calcific tendinopathy refractory to conservative medical treatment. Adhesive capsulitis of the shoulder is the most common complication (12%). Standard practice involves routine gleno-humeral exploration before calcification removal. The objective of this study was to identify risk factors for adhesive capsulitis. HYPOTHESIS: The development of adhesive capsulitis is associated with gleno-humeral exploration. METHODS: We conducted a multicentre, multi-surgeon, retrospective cohort study of 340 consecutive patients who underwent arthroscopic removal of rotator cuff calcifications between 1 January 2012 and 1 January 2018. We collected epidemiological data (age, sex, work-related physical activity), the history of previous treatments (local injections, needling), the type and location of the calcifications as assessed radiologically, the clinical findings (Constant score before and 6 months after surgery, diagnosis of adhesive capsulitis defined as shoulder pain with motion range limitation in all directions), and the surgical details (type of anaesthesia, gleno-humeral exploration). RESULTS: Of the 340 patients, 251 underwent routine gleno-humeral exploration and 89 did not. Adhesive capsulitis developed in 40 (12%) patients. By multivariate analysis, gleno-humeral exploration was an independent risk factor for adhesive capsulitis (p=0.022; odds ratio, 5.60). Of the 251 gleno-humeral explorations, 8% identified concomitant lesions and only 4% led to a curative procedure. CONCLUSION: Given our results and the data in the literature, we believe that routine gleno-humeral exploration during the arthroscopic treatment of rotator cuff calcific tendinopathy is inadvisable. LEVEL OF EVIDENCE: III; case-control study.

A REBOA Complication: EtCO2 Is Not Just a Marker of Cardiac Output.

We describe an as yet undescribed complication, namely, the perforation of the balloon at a distance from its introduction and the use of EtCO2 to suspect the diagnosis. Following a high-kinetic motorcycle accident, a 25-year-old patient was admitted in our level 1 trauma center, and benefited from a resuscitation thoracotomy followed by a REBOA catheter in zone 3. The use of a small caliber introducer could be responsible for balloon injury. EtCO2 is not only a marker of cardiac output and its sudden increase in this situation should raise questions about the recirculation of ischemia product and therefore the effectiveness of the occlusion balloon.

Neurosurgery for intracranial meningioma in patients aged more than 80 years: benefits and rationale.

BACKGROUND: Elderly patients with symptomatic benign intracranial tumours such as meningioma pose particular problems in decision making. We report on the outcome, morbidity and mortality in patients aged over 80 years after undergoing cranial surgery for meningiomas. METHODS: In this retrospective study, 37 patients aged more than 80 years underwent surgery at our neurosurgery department. The Karnofsky Performance Scale (KPS) was used to assess functional status. The American Society of Anesthesiologists (ASA) classification system, the Geriatric Scoring System, the Clinical-Radiological Grading System and the Sex, Karnofsky, ASA, Location and Edema score were used to define clinical status and tumour characteristics. The Charlson Comorbidity Index and Clavien-Dindo classification scores reflected therapeutic morbidity. RESULTS: Preoperative KPS scores were generally higher than 60 (n = 32). Of the 37 patients, 24 (64.8%) were in ASA class I or II, and 27 (73.0%) had one or more comorbidities. The median length of follow-up was 80.0 months (range: 1-96 months). The 1-year mortality rate was 2.7% (n = 1). Tumour control was achieved in 33 patients. At discharge, KPS scores were improved in 21 patients (with an average gain of +18.1 ± 8.7), stable in 10 patients and poorer in 6 patients. KPS scores improved or were stable in patients with shorter lengths of hospital stay (15.5 ± 17.9 days vs 51.4 ± 25.4 days; p < 0.01), those with Clavien-Dindo scores lower than 2 (p < 0.01) and those with less favourable preoperative KPS scores (69.4 ± 10.9 vs 82.0 ± 11.0; p = 0.04). CONCLUSION: Historically, surgery for intracranial meningiomas in patients aged >80 years has been feasible; this series demonstrated decreasing rates of postoperative mortality. Functional benefit should be the main goal of surgery. Perioperative morbidity should be better assessed and predicted because it significantly influences functional outcomes.

Pheochromocytoma surgery without systematic preoperative pharmacological preparation: insights from a referral tertiary center experience.

BACKGROUND: Despite significant advances in imaging and genetics, as well as surgical and anesthetic innovations, morbidity in pheochromocytoma surgery remains significant. The aim of this study was to identify the predictive factors of global and cardiovascular morbidity following unilateral laparoscopic adrenalectomy for pheochromocytoma. METHODS: We conducted a retrospective study from a unicentric cohort. All patients who underwent non-converted laparoscopic unilateral adrenalectomy for pheochromocytoma between 2000 and 2017 were included. Our patients did not systematically benefit from preoperative pharmacological preparation. It is to be noted that they never received alpha-blockers. Preoperative, intraoperative, and postoperative data during follow-ups were collected. Univariate and multivariate analyses by logistic regression were performed. RESULTS: A total of 134 patients were included. Fifty-three percent of patients did not receive preoperative pharmacological preparation (PPP) and 33% neither preoperative antihypertensives nor PPP before surgery. There was no postoperative mortality. The global morbidity was 13.4%, while cardiovascular morbidity was 4.5%. The main factors associated with global morbidity were preoperative diuretics, a medical history of stroke, and the need for pressor amines postoperatively. The main factor associated with cardiovascular morbidity was the need for pressor amines postoperatively. Predictive factors of postoperative need for pressor amines for hypotension were the tumor size, preoperative beta-blockers, and/or diuretics. CONCLUSION: In this large cohort of patients, our data revealed no mortality and low global and cardiovascular morbidity rates, showing that pheochromocytoma surgery without systematic PPP and even without preoperative antihypertensives is feasible and safe for selected patients. Our data also highlight the need for a good preoperative evaluation of the patient and the tumor, in order to optimize treatments and to help the detection of high-risk patients. This also allows us to better prevent and anticipate their possible complications.

Role of Cancer Surgery in the Improvement of the Operative Skills of Military Surgeons During Deployment: A Single-Center Study.

INTRODUCTION: The maintenance of military surgeons' operative skills is challenging. Different and specific training strategies have been implemented in this context; however, little has been evaluated with regard to their effectiveness. Cancer surgery is a part of military surgeons' activities in their home hospitals. This study aimed to assess the role of oncological surgery in the improvement of military surgeons' operative skills. METHODS: Between January and June 2019, the surgical activities of the departments of visceral, ear, nose, and throat, urological, and thoracic surgery were retrospectively reviewed and assessed in terms of the operative time (OT). All surgeons working at the Sainte Anne Military Teaching Hospital were sent a survey to rate on a 5-point scale the current surgical practices on their usefulness in improving surgical skills required for treating war injuries during deployment (primary endpoint) and to compare on a 10-point visual analog scale the influence of cancer surgery and specific training on surgical fluency (secondary endpoint). RESULTS: Over the study period, 2,571 hours of OT was analyzed. Oncological surgery represented 52.5% of the surgical activity and almost 1,350 hours of cumulative OT. Considering the primary endpoint, the mean rating allocated to cancer surgery was 4.53 ± 0.84, which was not statistically different than that allocated to trauma surgery (4.42 ± 1.02, P = 0.98) but higher than other surgery (2.47 ± 1.00, P < 0.001). Considering the secondary endpoint, cancer surgery was rated higher than specific training by all surgeons, without statistically significant difference (positive mean score of + 2.00; 95% IC: 0.85-3.14). CONCLUSION: This study demonstrates the usefulness of cancer surgery in improving the operative skills of military surgeons.

In COPD, Nocturnal Noninvasive Ventilation Reduces the FIO2 Delivered Compared With Long-Term Oxygen Therapy at the Same Flow.

BACKGROUND: Nocturnal noninvasive ventilation is recommended for patients with hypercapnic COPD. Long-term oxygen therapy improves survival in patients with hypoxemic disease. However, leaks during noninvasive ventilation are likely to reduce the fraction of inspired oxygen. OBJECTIVES: To compare nocturnal inspired O2 fractions during noninvasive ventilation with daytime pharyngeal inspired O2 fractions during nasal cannula oxygen therapy (with the same O2 flow) in patients with COPD at home (ie, real-life conditions). METHODS: This single-center prospective observational study included 14 subjects with COPD who received long-term O2 therapy. We analyzed pharyngeal inspired O2 fractions in the evening, with a nasopharyngeal probe (sidestream gas analyzer). The O2 flow was measured with a precision flow meter, at the usual flow. Then, the same O2 flow was implemented for noninvasive ventilation with a study's home ventilator. The all-night noninvasive ventilation parameters were delivered in pressure mode with a single-limb leaking circuit. Daytime and nighttime inspired O2 fractions were compared. RESULTS: The mean ± SD daytime pharyngeal inspired O2 fraction, measured with normobaric basal O2 flow, 0.308 ± 0.026%, was significantly higher than the mean ± SD nighttime inspired O2 fraction, measured during noninvasive ventilation (0.251 ± 0.011; P < .001). CONCLUSIONS: The nighttime inspired O2 fraction decreased with a modern noninvasive ventilation pattern, pressure target, and intentional leaks. This partial lack of O2 therapy is likely to be harmful. It might explain the poor results in all but 2 randomized controlled trials on long-term noninvasive ventilation in COPD. (ClinicalTrials.gov registration NCT02599246.).

Maintaining a high inspired oxygen fraction with the Elisée 350 turbine transport ventilator connected to two portable oxygen concentrators in an austere environment.

BACKGROUND: Management of critically ill patients requiring mechanical ventilation in austere environments or during disaster response is a logistic challenge. Availability of oxygen cylinders for mechanically ventilated patient may be difficult in such a context. A solution to ventilate patients requiring high fraction of inspired oxygen (FiO2) is to use a ventilator able to be supplied by a low-pressure oxygen source connected with two oxygen concentrators (OCs). We tested the Elisée 350 (ResMedBella Vista, Australia) ventilator paired with two Newlife Intensity 10 (Airsep, Ball Ground, Georgia) OCs and evaluated the delivered FiO2 across a range of minute volumes and combinations of ventilator settings. METHODS: The ventilators were attached to a test lung, OC flow was adjusted with a Certifier FA ventilator test systems from 2 to 10 L/min and injected into the oxygen inlet port of the Elisée 350. The FiO2 was measured by the analyzer integrated in the ventilator, controlled by the ventilator test system. Several combinations of ventilator settings were evaluated to determine the factors affecting the delivered FiO2. RESULTS: The Elisée 350 ventilator is a turbine ventilator able to deliver high FiO2 when functioning with two OCs. However, modifications of the ventilator settings such as an increase in minute ventilation affect delivered FiO2 even if oxygen flow is constant on the OC. CONCLUSION: The ability of two OCs to deliver high FiO2 when used with a turbine ventilator makes this method of oxygen delivery a viable alternative to cylinders to ventilate patients requiring an FiO2 of ≥80% in austere place or during disaster response. LEVEL OF EVIDENCE: Feasibility study on test bench, level V.

The Site of Oxygen Delivery Into a Home Ventilator Affects Recorded Volumes.

BACKGROUND: Long-term home mechanical ventilation is increasingly used by patients with chronic respiratory failure. Storage of medical data in the cloud is expanding, and ventilation can be monitored remotely. The aim of this bench study was to determine whether tidal volume (VT) can be affected by the location of supplemental oxygen placement. METHODS: We tested 4 home ventilators in a bench test using a dual-chamber test lung to test the addition of supplemental oxygen placement via a connector in the circuit (ie, front intake port) versus via the manufacturer's rear intake port, with different oxygen supply flows of 2, 4, 6, and 8 L/min. We compared the effectively delivered VT as measured with a pneumotachograph (ie, measured VT) versus the VT reported by each home ventilator (ie, monitored VT). RESULTS: For all of the home ventilators, the monitored VT and measured VT were comparable when the rear oxygen intake was used, regardless of oxygen flow. However, when the front oxygen intake was used, the monitored VT as measured by the ventilators was significantly lower than the measured VT, with the greatest difference reaching 29% for the highest oxygen flow tested (8 L/min). CONCLUSIONS: The monitored VT may be inaccurate if oxygen is added with a connector in the circuit, which may have consequences on both the individual level and collective level (ie, big data analysis). Physicians who analyze data from home ventilators should be aware of the site of oxygen supplementation and promote use of only the rear oxygen intake.