Brain Magnetic Resonance Imaging Responses to Nonhypoxic Hypobaric Decompression.

INTRODUCTION: The pathophysiological basis of neurological decompression sickness and the association between cerebral subcortical white matter (WM) change and nonhypoxic hypobaria remain poorly understood. Recent study of altitude decompression sickness risk evaluated acute WM responses to intensive hypobaric exposure using brain magnetic resonance imaging. METHODS: Six healthy men (20 to 50 yr) completed 6 h of hyperoxic hypobaria during three same-day altitude chamber decompressions to pressure altitudes ≥ 22,000 ft (6706 m). Research magnetic resonance imaging sequences, conducted on the days preceding and following decompression, evaluated subcortical WM integrity, cerebral blood flow, neuronal integrity (fractional anisotropy), and neurometabolite concentrations. RESULTS: No subcortical lesions were evident on diffusion weighted imaging and WM fractional anisotropy was unaffected. Mean WM blood flow was upregulated by 20% to over 25 mL · 100 g-1 · min-1. Gray matter flow was unchanged. There were no changes in gray matter or cerebellar neurometabolites. In parietal subcortical WM, levels of γ-aminobutyric acid (GABA) fell from (mean ± SD) 1.68 ± 0.2 to 1.35 ± 0.3 institutional units while glutathione (GSH) fell from 1.71 ± 0.4 to 1.25 ± 0.3 institutional units. Lactate increased postexposure in five subjects. CONCLUSIONS: Postexposure decrements in GABA and GSH imply WM insult with loss of neuroprotection and oxidative stress. An association between decrements in GABA and GSH support a common origin, while GSH decrements also correlate with WM blood flow responses. WM lactate increments are prone to error but suggest dysregulation of subcortical microvascular flow. WM neurometabolite and blood flow indices did not normalize by 24 h postexposure. Connolly D, Davagnanam I, Wylezinska-Arridge M, Mallon D, Wastling S, Lee VM. Brain magnetic resonance imaging responses to nonhypoxic hypobaric decompression. Aerosp Med Hum Perform. 2024; 95(10):733-740.

Decompression sickness in surface decompression breathing air instead of oxygen.

We report an unusual decompression sickness (DCS) incident in a commercial diving project. Eleven divers completed 91 dives to 23.5-36.2 m with bottom times ranging 23-67 min. The divers were breathing compressed air while immersed. Decompression was planned as surface decompression in a deck decompression chamber breathing oxygen typically for 15-30 min. Due to a technical error the divers breathed air rather than oxygen during the surface decompression procedure. Two divers suffered DCS. Both were recompressed on site with the same error resulting in them breathing compressed air rather than oxygen. One of them experienced a severe relapse with cardiovascular decompensation following recompression treatment. While DCS was expected due to the erroneous decompression procedures, it is noteworthy that only two incidents occurred during 91 dives with surface decompression breathing air instead of oxygen. Accounting for this error, the median omitted decompression time was 17 min (range 0-26 min) according to the Bühlmann ZHL-16C algorithm. These observations suggest that moderate omission of decompression time has a relatively small effect on DCS incidence rate. The other nine divers were interviewed in the weeks following completion of the project. None of them reported symptoms at the time, but five divers reported having experienced minor symptoms compatible with mild DCS during the project which was not reported until later.

Preventing postoperative moderate- and high-risk pressure injuries with artificial intelligence-powered smart decompression mattress on in middle-aged and elderly patients: a retrospective cohort analysis.

Aims/Background Artificial intelligence technology has attained rapid development in recent years. The integration of artificial intelligence applications into pressure reduction mattresses, giving rise to artificial intelligence-powered pressure reduction mattresses, is expected to provide personalised intelligent pressure reduction solutions, through automatic user's data-based adjustment of the patient's local pressure condition to prevent pressure injury. The purpose of this study was to investigate the effectiveness of artificial intelligence-powered smart decompression in the prevention of postoperative medium- and high-risk pressure injury in middle-aged and elderly patients. Methods A total of 400 middle-aged and elderly patients admitted to our hospital from June 2021 to December 2023 were selected as study subjects. Patients were categorised into observation and control groups according to the medical record system. General demographic data of the patients were collected. The propensity score matching method was used to balance the baseline data of the two groups of patients. The incidence, severity, complications and sleep quality in the matched study subjects were also compared. Results After matching, there were 96 patients in the two groups, and the differences in baseline data between the two groups were not statistically significant. Pressure injury and the total incidence of complications in the observation group were significantly lower than those in the control group (p < 0.05). Before treatment, there was no difference in the scores of all aspects of the Richards Campbell Sleep Questionnaire between the two groups (p > 0.05). After treatment, the scores of all aspects of Richards Campbell Sleep Questionnaire in the observation group were significantly lower than those in the control group (p < 0.05). Conclusion The artificial intelligence-powered smart decompression mattress can significantly prevent moderate- and high-risk pressure injury, effectively reducing the incidence of pressure injury and complications in postoperative long-term bedridden patients, alleviating the severity of pressure injury, relieving the pressure on various parts, and improving the sleep quality of patients.

Brain and Lung Biomarker Responses to Hyperoxic Hypobaric Decompression.

INTRODUCTION: Biomarker responses to intensive decompression indicate systemic proinflammatory responses and possible neurological stress. To further investigate responses, 12 additional brain and lung biomarkers were assayed.METHODS: A total of 15 healthy men (20 to 50 yr) undertook consecutive same-day ascents to 25,000 ft (7620 m), following denitrogenation, breathing 100% oxygen. Venous blood was sampled at baseline (T0), after the second ascent (T8), and next morning (T24). Soluble protein markers of brain and lung insult were analyzed by enzyme-linked immunosorbent assay with plasma microparticles quantified using flow cytometry.RESULTS: Levels of monocyte chemoattractant protein-1 and high mobility group box protein 1 were elevated at T8, by 36% and 16%, respectively, before returning to baseline. Levels of soluble receptor for advanced glycation end products fell by 8%, recovering by T24. Brain-derived neurotrophic factor rose by 80% over baseline at T24. Monocyte microparticle levels rose by factors of 3.7 at T8 and 2.7 at T24 due to early and late responses in different subjects. Other biomarkers were unaffected or not detected consistently.DISCUSSION: The elevated biomarkers at T8 suggest a neuroinflammatory response, with later elevation of brain-derived neurotrophic factor at T24 indicating an ongoing neurotrophic response and incomplete recovery. A substantial increase at T8 in the ratio of high mobility group box protein 1 to soluble receptor for advanced glycation end products suggests this axis may mediate the systemic inflammatory response to decompression. The mechanism of neuroinflammation is unclear but elevation of monocyte microparticles and monocyte chemoattractant protein-1 imply a key role for activated monocytes and/or macrophages.Connolly DM, Madden LA, Edwards VC, Lee VM. Brain and lung biomarker responses to hyperoxic hypobaric decompression. Aerosp Med Hum Perform. 2024; 95(9):667-674.

Narcotic Nitrogen Effects Persist after a Simulated Deep Dive.

Background and Objectives: Scuba divers often experience persistent inert gas narcosis (IGN) even after surfacing. This study aimed to test the hypothesis that breathing oxygen (O2) before surfacing can reduce postdive IGN. Materials and Methods: A group of 58 experienced divers underwent a 5 min dive at a depth of 50 m in a multi-place hyperbaric chamber. They were decompressed using air (air group). Another group of 28 divers (O2 group) breathed 100% O2 during the end of decompression. Prior to and after the dive, all participants performed the Sharpened Romberg test (SRT) and a modified tweezers test. Results: In the air group, the number of positive SRT results increased postdive (47% vs. 67%), indicating a greater impairment in the vestibular system (Cohen's d = 0.41). In the O2 group, the percentage of positive SRT results remained constant at 68% both before and after the dive. In terms of the modified tweezers test, the air group showed no significant change in the number of picked beads (40 ± 9 vs. 39 ± 7), while the O2 group demonstrated an increase (36 ± 7 vs. 44 ± 10) (Cohen's d = 0.34). Conclusion: The results reveal that the SRT revealed a negative effect of nitrogen (N2) on the vestibular system in the air group. The increased number of beads picked in the O2 group can be attributed to the learning effect, which was hindered in the air group. Consistent with our hypothesis, breathing O2 during decompression appears to reduce postdive IGN.

Active decompression during automated head-up cardiopulmonary resuscitation.

BACKGROUND: The combination of active compression-decompression cardiopulmonary resuscitation (ACD-CPR) with an impedance threshold device (ITD) and controlled head-up positioning (AHUP-CPR) is associated with improved outcomes compared with conventional CPR (C-CPR). This study focused on the role of active decompression (AD) during AHUP-CPR. METHODS: Farm pigs (n = 10, ∼40 kg) were anesthetized, intubated and ventilated. Physiological parameters and right ventricular pressure-volume loops were recorded continuously. Ventricular fibrillation was induced and left untreated for 10 mins, followed by automated C-CPR (2 min), ACD + ITD CPR in the flat position (2 min), and then AHUP-CPR with 3 cm of lift above the neutral chest position. After 15 min of CPR, AD was discontinued and then restarted incrementally to 4 cm. Data were analyzed with a linear mixed-effects model, using random intercepts for individual pigs. RESULTS: Upon cessation of AD during AHUP-CPR, decompression right atrial pressure (+59%) increased (p < 0.01), whereas multiple hemodynamic parameters positively associated with perfusion, including coronary (-25%) and cerebral perfusion pressures (-11%), end-tidal CO2 (-13%), stroke volume and cardiac output (-26%), decreased immediately and significantly with p < 0.05. Restoration of AD reduced right atrial pressure and increased positive perfusion parameters in an incremental manner. Only with ≥ 3 cm of AD were all hemodynamic parameters restored to ≥ 90% of pre-AD discontinuation levels. CONCLUSION: Full chest wall lift, achieved with ≥ 3 cm of AD, was needed to maintain and optimize hemodynamics during AHUP-CPR in pigs. These findings should be considered when optimizing care with this new approach.

Relative Severity of Human Performance Decrements Recorded in Rapid vs. Gradual Decompression.

INTRODUCTION: Cabin decompression presents a threat in high-altitude-capable aircraft. A chamber study was performed to compare effects of rapid (RD) vs. gradual decompression and gauge impairment at altitude with and without hypoxia, as well as to assess recovery.METHODS: There were 12 participants who completed RD (1 s) and Gradual (3 min 12 s) ascents from 2743-7620 m (9000-25000 ft) altitude pressures while breathing air or 100% O2. Physiological indices included oxygen saturation (SPo2), heart rate (HR), respiration, end tidal O2 and CO2 partial pressures, and electroencephalography (EEG). Cognition was evaluated using SYNWIN, which combines memory, arithmetic, visual, and auditory tasks. The study incorporated ascent rate (RD, gradual), breathing gas (air, 100% O2) and epoch (ground-level, pre-breathe, ascent-altitude, recovery) as factors.RESULTS: Physiological effects in hypoxic "air" ascents included decreased SPo2 and end tidal O2 and CO2 partial pressures (hypocapnia), with elevated HR and minute ventilation (V˙E); SPo2 and HR effects were greater after RD (-7.3% lower and +10.0 bpm higher, respectively). HR and V˙E decreased during recovery. SYNWIN performance declined during ascent in air, with key metrics, including composite score, falling further (-75% vs. -50%) after RD. Broad cognitive impairment was not recorded on 100% O2, nor in recovery. EEG signals showed increased slow-wave activity during hypoxia.DISCUSSION: In hypoxic exposures, RD impaired performance more than gradual ascent. Hypobaria did not comprehensively impair performance without hypoxia. Lingering impairment was not observed during recovery, but HR and V˙E metrics suggested compensatory slowing following altitude stress. Participants' cognitive strategy shifted as hypoxia progressed, with efficiency giving way to "satisficing," redistributing effort to easier tasks.Beer J, Mojica AJ, Blacker KJ, Dart TS, Morse BG, Sherman PM. Relative severity of human performance decrements recorded in rapid vs. gradual decompression. Aerosp Med Hum Perform. 2024; 95(7):353-366.

Eccentric exercise before a 90 min exposure at 24,000 ft increases decompression strain depending on body region but not total muscle mass recruited.

Eccentric upper-body exercise performed 24 h prior to high-altitude decompression has previously been shown to aggravate venous gas emboli (VGE) load. Yet, it is unclear whether increasing the muscle mass recruited (i.e., upper vs. whole-body) during eccentric exercise would exacerbate the decompression strain. Accordingly, this study aimed to investigate whether the total muscle mass recruited during eccentric exercise influences the decompression strain. Eleven male participants were exposed to a simulated altitude of 24,000 ft for 90 min on three separate occasions. Twenty-four hours before each exposure, participants performed one of the following protocols: (i) eccentric whole-body exercise (ECCw; squats and arm-cycling exercise), (ii) eccentric upper-body exercise (ECCu; arm-cycling), or (iii) no exercise (control). Delayed onset muscle soreness (DOMS) and isometric strength were evaluated before and after each exercise intervention. VGE load was evaluated at rest and after knee- and arm-flex provocations using the 6-graded Eftedal-Brubakk scale. Knee extensor (-20 ± 14%, P = 0.001) but not elbow flexor (-12 ± 18%, P = 0.152) isometric strength was reduced 24 h after ECCw. ECCu reduced elbow flexor isometric strength at 24 h post-exercise (-18 ± 10%, P < 0.001). Elbow flexor DOMS was higher in the ECCu (median 6) compared with ECCw (5, P = 0.035). VGE scores were higher following arm-flex provocations in the ECCu (median (range), 3 (0-4)) compared with ECCw (2 (0-3), P = 0.039) and control (0 (0-2), P = 0.011), and in ECCw compared with control (P = 0.023). VGE were detected earlier in ECCu (13 ± 20 min) compared with control (60 ± 38 min, P = 0.021), while no differences were noted between ECCw (18 ± 30 min) and control or ECCu. Eccentric exercise increased the decompression strain compared with control. The VGE load varied depending on the body region but not the total muscle mass recruited. HIGHLIGHTS: What is the central question of this study? Does exercise-induced muscle damage (EIMD) resulting from eccentric exercise influence the presence of venous gas emboli (VGE) during a 90 min continuous exposure at 24,000 ft? What is the main finding and its importance? EIMD led to an earlier manifestation and greater VGE load compared with control. However, the decompression strain was dependent on the body region but not the total muscle mass recruited.

The effect of a single closed-circuit rebreather decompression dive in extremely cold water to cardiac function.

PURPOSE: Dive-induced cardiac and hemodynamic changes are caused by various mechanisms, and they are aggravated by cold water. Therefore, aging divers with pre-existing cardiovascular conditions may be at risk of acute myocardial infarction, heart failure, or arrhythmias while diving. The aim of this study was to assess the effect of a single decompression CCR dive in arctic cold water on cardiac function in Finnish technical divers. METHODS: Thirty-nine divers performed one identical 45 mfw CCR dive in 2-4 °C water. Hydration and cardiac functions were assessed before and after the dive. Detection of venous gas embolization was performed within 120 min after the dive. RESULTS: The divers were affected by both cold-water-induced hemodynamic changes and immersion-related fluid loss. Both systolic and diastolic functions were impaired after the dive although the changes in cardiac functions were subtle. Venous inert gas bubbles were detected in all divers except for one. Venous gas embolism did not affect systolic or diastolic function. CONCLUSION: A single trimix CCR dive in arctic cold water seemed to debilitate both systolic and diastolic function. Although the changes were subtle, they appeared parallel over several parameters. This indicates a real post-dive deterioration in cardiac function instead of only volume-dependent changes. These changes are without a clinical significance in healthy divers. However, in a population with pre-existing or underlying heart problems, such changes may provoke symptomatic problems during or after the dive.

Descompresión de fosa posterior sin duroplastia expansiva en adulto con malformación de Chiari tipo 1-siringomielia / Posterior fossa decompression without expansive duroplasty in an adult with Chiari malformation type 1-syringomyelia

Introducción: La malformación de Chiari tipo 1 incluye un grupo heterogéneo de malformaciones congénitas, caracterizadas por el descenso caudal del cerebelo a través del foramen magno. En un 30-70 por ciento de los casos tiene siringomielia asociada. Existen controversias en torno a la técnica quirúrgica ideal. Objetivo: Presentar un caso de MC-1 asociada a siringomielia en el que no se aplica una duroplastia expansiva. Presentación de caso: Paciente femenina de 43 años, con antecedentes de hipertensión arterial. Acudió a consulta neuroquirúrgica por dolor cervical irradiado al miembro superior derecho. Al examen neurológico mostró signos de afectación de primera y segunda motoneurona. La resonancia magnética confirmó el diagnóstico de MC-1. Se intervino quirúrgicamente mediante descompresión de fosa posterior sin duroplastia expansiva. La paciente evolucionó sin complicaciones y egresó a las 48 horas. Durante el seguimiento mejoraron las manifestaciones parestésicas; sin embargo, el examen neurológico se mantuvo igual. A los seis meses, la resonancia magnética indicó una marcada disminución de la siringomielia y la reconformación de la cisterna magna. Hasta los 18 meses del tratamiento, los síntomas no habían empeorado y la capacidad funcional resultaba aceptable (Karnofsky 90/100). Conclusiones: La descompresión de fosa posterior sin duroplastia expansiva, seguida de re-permeabilización microquirúrgica del foramen de Magendie, tuvo resultados favorables en este caso(AU)

Introduction: Chiari malformation type 1 includes a heterogeneous group of congenital malformations, characterized by caudal descent of the cerebellum through the foramen magnum. It has associated syringomyelia in 30-70 percent of cases. Controversies exist regarding the ideal surgical technique. Objective: To present a case of MC-1 associated with syringomyelia in which an expansive duroplasty is not applied. Case report: Female patient, 43 years old, with history of arterial hypertension. She went to the neurosurgical consultation for cervical pain radiating to the right upper limb. On neurological examination, she showed signs of first and second motor neuron involvement. MRI confirmed the diagnosis of MC-1. She underwent surgery by decompression of the posterior fossa without expansive duroplasty. The patient evolved without complications and she was discharged after 48 hours. During the follow-up, the paresthetic manifestations improved; however, the neurological examination remained the same. At six months, MRI indicated a marked decrease in syringomyelia and reshaping of the cisterna magna. Until 18 months after treatment, symptoms had not worsened and functional capacity was acceptable (Karnofsky 90/100). Conclusions: Posterior fossa decompression without expansive duroplasty, followed by microsurgical re-permeabilization of Magendie's foramen, had favorable results in our case(AU)

Proposed Thalmann algorithm air diving decompression table for the Swedish Armed Forces.

The Swedish Armed Forces (SwAF) air dive tables are under revision. Currently, the air dive table from the U.S. Navy (USN) Diving Manual (DM) Rev. 6 is used with an msw-to-fsw conversion. Since 2017, the USN has been diving according to USN DM rev. 7, which incorporates updated air dive tables derived from the Thalmann Exponential Linear Decompression Algorithm (EL-DCM) with VVAL79 parameters. The SwAF decided to replicate and analyze the USN table development methodology before revising their current tables. The ambition was to potentially find a table that correlates with the desired risk of decompression sickness.  New compartmental parameters for the EL-DCM algorithm, called SWEN21B, were developed by applying maximum likelihood methods on 2,953 scientifically controlled direct ascent air dives with known outcomes of decompression sickness (DCS). The targeted probability of DCS for direct ascent air dives was ≤1% overall and ≤1‰ for neurological DCS (CNS-DCS). One hundred fifty-four wet validation dives were performed with air between 18 to 57 msw. Both direct ascent and decompression stop dives were conducted, resulting in incidences of two joint pain DCS (18 msw/59 minutes), one leg numbness CNS-DCS (51 msw/10 minutes with deco-stop), and nine marginal DCS cases, such as rashes and itching. A total of three DCS incidences, including one CNS-DCS, yield a predicted risk level (95% confidence interval) of 0.4-5.6% for DCS and 0.0-3.6% for CNS-DCS. Two out of three divers with DCS had patent foramen ovale. The SWEN21 table is recommended for the SwAF for air diving as it, after results from validation dives, suggests being within the desired risk levels for DCS and CNS-DCS.

Scientific shallow saturation dive expedition using diving rebreathers and a specific dry habitat: medical management of the "Capsule" programme.

BACKGROUND: Scientific underwater exploration could benefit from professional diving facilities. This could allow marine research for durations far exceeding anything currently possible. The closed-circuit rebreather expansion provides new perspectives by unleashing divers and their diving bell. "Under the Pole Expeditions" developed an innovative compact underwater habitat for this purpose. MATERIALS AND METHODS: The habitat's depth was fixed at 20 m. Saturation lasted 3 days and was followed by a 245 min long decompression procedure with mandatory in-water phase. Isolation and environmental constraints will require specific medical and safety procedures. "In situ" medical concerns were considered, and a specific evacuation plan was established. This report describes the medical management of this atypical project and the systematic clinical follow-up mostly targeted on the cardiovascular system, fatigue and psychological tolerance. RESULTS: Seventeen individual saturation exposures were performed. All selected divers were professional. Neither severe illness nor decompression sickness was observed. These short-term saturation exposures appeared to be well tolerated. There was a relatively low bubble grade after decompression. Psychological tolerance appeared good. However, a transient moderate orthostatic hypotension suggested cardiovascular deconditioning after dive. CONCLUSIONS: This first experiment demonstrates the interest and feasibility of a shallow revisited saturation dive with rebreather use. This isolation requires medical accompaniment and rigorous preparation. Medical and physiological risks assessment is essential in this context and must be consolidated by new experiences.

A review of accelerated decompression from heliox saturation in commercial diving emergencies.

INTRODUCTION: Saturation diving is a specialised method of intervention in offshore commercial diving. Emergencies may require the crew to be evacuated from the diving support vessel. Because saturation divers generally need several days to reach surface, the emergency evacuation of divers is based on dedicated hyperbaric rescue systems. There are still potential situations for which these systems cannot be used or deployed, and where an emergency decompression provides an alternative solution. METHODS: Our objective was to describe historical cases and assess the benefit of emergency decompressions, with the collection of data from the authors' direct experience and networks, providing witness or first-hand information. RESULTS: We documented three cases of emergency decompression following bell evacuations, and six cases of accelerated decompression performed in the chamber or hyperbaric rescue chamber. Review of these cases showed: 1) the complicated nature of such emergencies that make decisions difficult; 2) the variety of solutions implemented; and 3) the surprisingly safe and successful outcomes of several operations. Analysis of the accelerated decompression occurrences allowed derivation of the options used; upward initial excursion, increased chamber partial pressure of oxygen associated to increased ascent rates, and inert gas switching. We identified four published procedures for accelerated decompression. CONCLUSIONS: Despite modern hyperbaric rescue systems, accelerated decompression remains an essential tool in case of emergency. The diving industry needs clear guidance on what can be achieved, depending on the saturation depth and the level of emergency.

A prospective single-blind randomised clinical trial comparing two treatment tables for the initial management of mild decompression sickness.

INTRODUCTION: Limited evidence suggests that shorter recompression schedules may be as efficacious as the US Navy Treatment Table 6 (USN TT6) for treatment of milder presentations of decompression sickness (DCS). This study aimed to determine if divers with mild DCS could be effectively treated with a shorter chamber treatment table. METHODS: All patients presenting to the Fremantle Hospital Hyperbaric Medicine Unit with suspected DCS were assessed for inclusion. Participants with mild DCS were randomly allocated to receive recompression in a monoplace chamber via either a modified USN TT6 (TT6m) or a shorter, custom treatment table (FH01). The primary outcome was the number of treatments required until resolution or no further improvement (plateau). RESULTS: Forty-one DCS cases were included, 21 TT6m and 20 FH01. Two patients allocated to FH01 were moved to TT6m mid-treatment due to failure to significantly improve (as per protocol), and two TT6m required extensions. The median total number of treatments till symptom resolution was 1 (IQR 1-1) for FH01 and 2 (IQR 1-2) for TT6m (P = 0.01). More patients in the FH01 arm (17/20, 85%) showed complete symptom resolution after the initial treatment, versus 8/21 (38%) for TT6m (P = 0.003). Both FH01 and TT6m had similar overall outcomes, with 19/20 and 20/21 respectively asymptomatic at the completion of their final treatment (P = 0.97). In all cases where two-week follow-up contact was made, (n = 14 FH01 and n = 12 TT6m), patients reported maintaining full symptom resolution. CONCLUSIONS: The median total number of treatments till symptom resolution was meaningfully fewer with FH01 and the shorter treatment more frequently resulted in complete symptom resolution after the initial treatment. There were similar patient outcomes at treatment completion, and at follow-up. We conclude that FH01 appears superior to TT6m for the treatment of mild decompression sickness.

Decompression Illness Treated with the Hart-Kindwall Protocol in a Monoplace Chamber.

BACKGROUND Hyperbaric oxygen (HBO2) therapy in a multiplace chamber is the standard treatment for severe altitude decompression illness (DCI). However, some hospitals may only have a monoplace chamber. Herein, we present the case of a patient with severe altitude DCI caused by rapid decompression during an actual flight operation that was successfully treated through emergency HBO2 therapy with the Hart-Kindwall protocol, a no-air-break tables with the minimal-pressure oxygen approach in a monoplace chamber due to unavailability of rapid access to a multiplace chamber. CASE REPORT A 34-year-old male aviator presented with chest pain, paresthesia, and mild cognitive impairment following rapid decompression 20 minutes after take-off, which comprised 10 minutes of reaching a height of 10 058 m (33 000 feet) and 10 minutes of cruising at that altitude. He then initiated flight descent and landing. He visited a primary clinic, and severe DCI was suggested clinically. However, since the closest hospital with a multiplace chamber was a 3-hour drive away, we provided emergency HBO2 therapy with the Hart-Kindwall protocol in a monoplace chamber at a nearby hospital 4 hours after the initial decompression. He recovered fully and returned to flight duty 2 weeks later. CONCLUSIONS Emergency HBO2 therapy with the Hart-Kindwall protocol in a monoplace chamber may be a suitable option for severe DCI, especially in remote locations with no access to facilities with a multiplace chamber. However, prior logistical coordination must be established to transfer patients to hospitals with multiplace chambers if their symptoms do not resolve.

Controlled Decompression Alleviates Brain Injury via Attenuating Oxidative Damage and Neuroinflammation in Acute Intracranial Hypertension.

BACKGROUND: The benefits of controlled decompression (CDC) for patients with acute intracranial hypertension especially in terms of alleviating the complications caused by rapid decompression (RDC) have been confirmed by clinical studies. This study is aimed at evaluating the therapeutic potency of CDC with ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) by investigating the potential molecular mechanism in the acute intracranial hypertension (AICH) rabbit model. METHODS: Male New Zealand white rabbits were randomly subdivided into the sham-operated (SH) group, CDC group, and RDC group. Blood plasma samples and brain tissue were collected 2 days before operation (baseline) and at 3, 6, 24, and 72 hours after operation to measure the levels of UCH-L1, GFAP, oxidative stress indicators, and inflammatory cytokines by performing ELISA or Western blot. The neurological score of the rabbits and brain water content was graded 24 h after surgery. qPCR, immunofluorescence, and FJ-C staining were conducted. RESULTS: CDC improved neurological function, lowered brain water content, ameliorated neuronal degeneration, attenuated oxidative damage, and inflammatory responses to a greater extent than RDC. Plasma UCH-L1 level was significantly lower in the CDC group at 3 h postoperatively than in the RDC group. CDC reduced plasma GFAP levels to various degrees at 3 h, 6 h, and 24 h postoperatively compared with RDC. Immunofluorescence confirmed that the expression of UCH-L1 and GFAP in the cortex of the CDC group was lower than that of the RDC group. CONCLUSIONS: Our data collectively demonstrate that CDC could attenuate oxidative damage and inflammatory responses, downregulate UCH-L1 and GFAP levels, and contribute to an improved neuroprotective effect compared with RDC.

A safety assessment of a 300-meter saturation dive at sea by mental ability and performance efficacy.

High pressure is an environmental characteristic of the deep sea that may exert critical effects on the physiology and mental abilities of divers. In this study we evaluated the performance efficacy and mental ability of four divers during a 300-meter helium-oxygen saturation dive at sea. Spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability were examined for four divers during the pre-dive, compression, decompression, and post-dive phases. The results showed that both the reaction time and the correct responses for the mental rotation and hand-eye coordination were slightly fluctuated. In addition, there was a significant decline in the grip strength of the left hand. It is concluded that the performance efficacy and mental ability of divers were virtually unaffected during 300-meter helium-oxygen saturation diving at sea.

Nonsurgical spinal decompression system traction combined with electroacupuncture in the treatment of multi-segmental cervical disc herniation: A case report.

RATIONALE: With the spread of computers and mobile phones, cervical spondylosis has become a common occupational disease in clinics, which seriously affects the quality of life of patients. We used a nonsurgical spinal decompression system (SDS) combined with physical therapy electroacupuncture (EA) to treat a case of mixed cervical spondylosis caused by multi-level cervical disc herniation, and we achieved satisfactory results. PATIENT CONCERNS: A 44-year-old Caucasian Asian woman presented with neck pain and numbness on the left side of the limb. MRI showed the patient's C3-C7 segment cervical disc herniation, and the flexion arch of the cervical spine was reversed. DIAGNOSIS: The patient was diagnosed with a mixed cervical spondylosis. INTERVENTIONS: The patient received a month of physical therapy (SDS traction combined with EA). OUTCOMES: Before and after treatment: VAS score of neck pain decreased from 8 to 0; Cervical spine mobility returned to normal; The grip strength of left hand increased from 7.5 kg to 19.2 kg; Cervical curvature index changed from -16.04% to -3.50%; the physiological curvature of the cervical spine was significantly restored. There was no dizziness or neck discomfort at 6 month and 1 year follow-up. LESSONS SUBSETIONS: SDS traction combined with EA is effective for the treatment of cervical disc herniation and can help restore and rebuild the biomechanical balance of the cervical spine.

Transanal decompression tube is superior to self-expandable metallic colonic stent for malignant colorectal obstruction: a retrospective study.

BACKGROUND: The surgical management of left-sided malignant large bowel obstruction (MLBO) is associated with high morbidity and mortality. Recently, self-expandable metallic colonic stent (SEMS) and transanal decompression tube (TDT) used as a 'bridge to surgery' (BTS) have been widely used. This study aims to compare the clinical outcomes and oncological safety of SEMS and TDT as BTS to transform MLBO into elective surgery. METHODS: Between February 2013 and March 2019, 62 patients with MLBO received SEMS (n = 32) or TDT (n = 30), and elective one-stage surgery later. We evaluated decompression efficiency and oncological safety in selective operation in TDT and SEMS groups, including preoperative preparation time, surgical approach, number of lymphatic dissection and vascular invasion, ulcer formation and histopathological findings of resected specimens. RESULTS: The preoperative preparation time in the SEMS group was shorter than that of the TDT group (P < 0.05). However, there was no significant difference between the groups in postoperative length of hospital stay (P > 0.05). The number of vascular invasions in the TDT group was less than that in the SEMS group (P < 0.05). Furthermore, the risk of wound abscess and ulcer formation in the TDT group was significantly lower than that in the SEMS group (P < 0.05). CONCLUSION: Our findings suggest that SEMS is associated with a relatively poor oncological outcome and the placement of TDT as BTS in MLBO patients may be a better alternation.