Diffusive Respiration Research Articles

Effect of nickel ions on ecotoxicological responses of the great ramshorn Planorbarius corneus allospecies (Mollusca: Gastropoda: Pulmonata: Planorbidae) of the Ukrainian river network

This ecotoxicological study analyzed the impact of Ni2+ ions in different concentrations on the ecotoxicological and physiological features of the western and eastern vicariant allospecies of the great ramshorn superspecies Planorbarius corneus (Linnaeus, 1758) sensu lato in Ukrainian populations from rivers in two different nature-geographic zones: Forest (Polissia) and Forest-Steppe. The two allospecies differed from each other significantly (p≤0.05–0.001) in their responses to the main ecotoxicological indexes (LC0, LC50, LC100) in terms of the duration of the latent period, lethal time and mortality rate. By all these indices, the western allospecies had significantly more tolerance than the eastern allospecies. The same was true also for respiratory responses. Under the MPC (maximum permissible concentration) of Ni2+ ions in the environment, no changes were registered compared to the control. Increase in toxicant concentration up to 2 MPC was followed by increase in the rate, number, volume and duration of inspirations. At 3 MPC of Ni2+, however, the indices of direct diffusive respiration progressively decreased. In all measures, the western allospecies appeared better able to adjust to, and to survive increasing concentrations of Ni2+ than that from the east.

Вплив іонів Cu (II) на легеневе й поверхневе дихання аловидів Planorbarius corneus s. l. (Mollusca, Gastropoda, Pulmonata) гідромережі України

One of the urgent problems of modern hydroecology is an increasing pollution of Earth hydrosphere by heavy metal ions. The necessity of this problem’s solution within Ukrainian river network is caused by the recent intensification of polluting of its surface waters by these pollutants. That is why the identification the species-indicators for level of pollution by Cu (II) ions in nature water bodies among the most widespread and numerous Ukrainian mollusks is an expedient task. We aimed at question: whether or not the great ramshorn, the only representative of genus Planorbarius Dumeril, 1806 in Northern hemisphere, can be assigned to such a category? For this purpose, we establishedof the influence of Cu (II) ions within the concentrations of 0.5 MPC to 3 MPC were studied on the indicators of lung and direct surface diffusive respirations of the “western” and “eastern” genetic vicaristic allospecies of great ramshorn Planorbarius corneus s. l. in the hydrological river network of Ukraine. These mollusсs, like all Pulmonata, have a bimodal respiration pattern. They use their true lungs for atmospheric oxygen breathing and the diffusive (surface) respiration is used for soluble in the water oxygen consumption. The aim of present study was to clarify the features and difference levels of lung and surface diffusive respiration of “western” and “eastern” allospecies under the impact of Cu (II) ions in water environment (MPC: 0,5, 1, 2, 3). It was established that the endurance coefficient for concentrations Cu (II) in water environment appeared lower in “eastern” allospecies to those in “western” allospecies. Under the same concentrations of toxicants used the lethality of “eastern” allospecies was higher than that of “western” allospecies in all cases. The indexec of lung and direct diffusive respiration in the allospecies of great ramshorn P. corneus s. l. under the impact of the Cu (II) ions concentration in water environment demonstrated that “eastern” allospecies tends to regress under the increased environmental pollution more comparing to “western” allospecies (р≤0,05–0,001).

Impact of some mineral fertilizers on the pulmonary and direct surface respiration of the allospecies of Planorbarius corneus superspecies (Gastropoda: Pulmonata: Planorbidae) from the Ukrainian water bodies

The vicariant genetic allospecies of the superspecies complex of the great ramshorn snail Planorbarius corneus s. lato, “western” and “eastern” – in Right Bank and Left Bank Ukraine, respectively, – are among the widespread and numerous gastropods in the Ukrainian river network. They possess two modes of respiration: pulmonary and surface (diffusive). The gas exchange in these snails is connected to the presence of the respiratory pigment hemoglobin in their internal liquid medium (hemolymph), which transports oxygen in their tissues and organs, and carbon dioxide to the lungs. We studied the features of impact of three mineral fertilizers widespread in Ukraine (nitrate, potassium and phosphate) used in concentrations measured in MPC 0.01 mg/L (0.5, 1, 2, 3) on the indexes of pulmonary and surface diffusive respiration in both P. corneus s. lato allospecies. Exposure of experimental individuals to 0.5 MPC-solutions of mentioned fertilizers does not affect them. The increase of toxicant concentration up to 2 MPC, however, is followed by an increase in respiratory activity (p≤0.05–0.001), but beyond that up to 3 MPC induces a significant decline (p≤0.001). Considered individually, the examined mineral fertilizers presented the following order by their impact on great ramshorns: nitrate > potassium > phosphate. The “eastern” allospecies appeared to be more sensitive and less durable for all aforementioned pollutants by both lung and direct diffusive respiration, compared to the “western” allospecies (p≤0.05–0.001).

ВПЛИВ Zn2+ ВОДНОГО СЕРЕДОВИЩА НА ДОБОВУ ЦИКЛІЧНІСТЬ ДИХАННЯ АЛОВИДІВ PLANORBARIUS CORNEUS S. L. (MOLLUSCA, GASTROPODA, PLANORBIDAE)

We investigated the impact of the different concentrations of Zn2+ in the water (in the 0.5 MPL – 3 MPL range) on the chronological features of lung and direct diffusive respiration in representatives of superspecies complex of ramshorns Planorbarius corneus s. l. (“eastern” and “western” allospecies) from the Ukrainian river network. They have a bimodal respiration. Atmospheric oxygen goes into their true lungs through the breathing pore – pneumostome, – during the periodical rises up to the water surface tension film. And the oxygen soluble in the water is acquired by the osmosis through the epithelial body coverings and the surface of adaptive gill. Both ways are almost equally important for the oxygen supply of mollusks’ organisms.
 Zn2+ ions are the powerful toxins of local effect for ramshorns. The excess of the MPL may lead to the impairment of stable homeostasis. Both P. corneus allospecies s. l. have clearly expressed diurnal cyclicality of their lung respiration (in the “day-night” rhythm). They perform 1.2–1.3 times more “inhales” during the day with the shorter (1.3–1.4 times) intervals. This apparently is the consequence of physiological activity increasing in the period of their most intensive life-giving metabolic processes occurring. 
 Under the 0.5 MPL of Zn2+ there were no statistically significant changes in lung and direct diffusive respirations indexes (comparing to the control) in both allospecies during the latent phase of their intoxication process. “Inhales” during the day were 1.1 time longer than during the night in experimental animals. This let mollusks replenish the amount of oxygen they underreceived due to the decreased number of night “inhales”.
 Under MPL Zn2+ level the respirational indexes of ramshorns (number, length and volume of “inhales” and intervals between them) increased in average 1.1 times. Their feeding and moving behaviors visibly activated, which promoted the increasing of the daily frequency of their respiration rhythm. Under the 2 MPL concentration of Zn2+ there was further significant increasing (p

Effect of zinc ions on the lung and cutaneous diffusive respiration of the great ramshorn Planorbarius corneus allospecies (Mollusca: Gastropoda: Pulmonata: Planorbidae) of the Ukrainian river network

Toxicological studies were performed to analyze the effect of Zn2+ in different concentrations on the lung and cutaneous diffusive respiration of great ramshorn Planorbarius corneus (Linnaeus, 1758) allospecies from the two geographically separate populations. At 0.5 MPC Zn2+ in the water containing experimental molluscs, there were no statistically significant changes in the number or duration of inspirations compared to the control. Increasing the concentration of toxicant to 2 MPC was accompanied by a sharp increase in both (p≤0.001), as also in the volume of inspirations (p≤0.05). Increasing concentrations to 5 and 10 MPC was followed by drastic and statistically significant impairments of pulmonary respiration indices. Avoidance also collapsed at these higher concentrations, and the accumulation of thick mucus inhibiting respiration resulted in heavy mortality. Trends were the same in both “western” and “eastern” allospecies, although the latter appeared marginally less resistant. The main reason for changes in respiratory function is the damage inflicted by toxicant on the lung and cutaneous respiratory epithelium. The effects are highly intensified production of mucus which completely blocks oxygen intake by cutaneous epithelium and induces cell death in the respiratory epithelium.

Іnfluence of some heavy metals to the pulmonary and direct diffusive respiration of the great ramshorn Planorbarius corneus allospecies (Mollusca: Gastropoda: Planorbidae) from the Ukrainian river system

The vicaristic genetic allospecies (“western” and “eastern”) of superspecies complex Planorbarius corneus s. lato from Ukrainian river network have the combined bimodal respiration mode. These molluscs use their true lungs for atmospheric oxygen breathing, and the diffusive (surface) respiration is used for soluble oxygen consumption. Oxygen transportation to different tissues and organs and carbon dioxide from them to lungs occurs due to respiratory pigment hemoglobin in their liquid internal medium (hemolymph), circulating in vessels, lacunas and sinuses of these animals’ open circulatory system. The aim of present study was to clarify the features and difference levels of lung and surface respiration for “western” and “eastern” allospecies under the impact of heavy metal ions in water environment (MPC: 0.5, 1, 2, 3). It was established that the toxins could be ranged by their toxicity level for activation of molluscs’ respiratory function: Cu2+>Zn2+>Ni2+ >Mn2+. The “eastern” allospecies appeared to be more sensitive and less durable for all aforementioned toxins by both lung and direct diffusive respiration, comparing to the “western” allospecies.

Variability in Benthic Ecosystem Functioning in Arctic Shelf and Deep-Sea Sediments: Assessments by Benthic Oxygen Uptake Rates and Environmental Drivers

Remineralization of organic matter at the seafloor is an important ecosystem function, as it drives carbon and nutrient cycling, supplying nutrients for photosynthetic production, but also controls carbon burial within the sediment. In the Arctic Ocean, changes in primary production due to rapid sea-ice decline and thinning affect the export of organic matter to the seafloor and thus, benthic ecosystem functioning. Due to the remoteness and difficult accessibility of the Arctic Ocean, we still lack baseline knowledge about patterns of benthic remineralization rates and their drivers in both shelf and deep-sea sediments. Particularly comparative studies across regions are scarce. Here, we address this knowledge gap by contrasting benthic diffusive and total oxygen uptake rates (DOU and TOU), both established proxies of the benthic remineralization function, between shelf and deep-sea habitats of the Barents Sea and the central Arctic Ocean, sampled during a RV Polarstern expedition in 2015. DOU and TOU were measured using ex situ porewater oxygen microprofiles and sediment core incubations, respectively. In addition, contextual parameters including organic matter availability and microbial cell numbers were determined as environmental predictors. Pan-Arctic regional comparisons were obtained by extending our analyses to previously published data from the Laptev and Beaufort Seas. Our results show that (1) benthic oxygen uptake rates and most environmental predictors varied significantly between shelf and deep-sea habitats; (2) the availability of detrital organic matter is the main driver for patterns in total as well as diffusive respiration, while bacterial abundances were highly variable and only a weak predictor of differences in TOU and DOU; (3) regional differences in oxygen uptake across shelf and deep-sea sediments were mainly related to organic matter availability and may reflect varying primary production regimes and distances to the nearest shelf. Our findings suggest that the expected decline in sea-ice cover and the subsequent increase in export of organic matter to the seafloor may particularly enhance remineralization in the deep seas of the Arctic Ocean, altering benthic ecosystem functioning in future climate scenarios.

717 Using the VDR to Safely Transport Critically Ill Burn Patients to the OR

Abstract Introduction Critically ill burn patients’ inability to tolerate conventional mechanical ventilation often results in delays, postponements and cancellations of surgical interventions. Early intervention with surgical excision and debridement can help prevent infection, multi-system organ failure and mortality. Severe burn victims often sustain lung injury due to inhalation of toxic smoke and heated gases. Severe respiratory distress due to smoke inhalation has been associated with a mortality of up to 80%. The application of conventional mechanical ventilation can rupture healthy alveoli and may intensify lung injury due to the constant opening and closing of lung units. Volumetric diffusive respiration allows for the diffusion of oxygen via intrapulmonary percussion with convective removal of carbon dioxide. This mode of ventilation in burn patients aids in the clearance of small airway debris. Diffusive oxygenation provides alveolar protection by eliminating repetitive opening and closing while convective forces provide CO2 and debris clearance. At our facility, with the assistance of the Volumetric Diffusive Respirator (VDR), we have been able to successfully stabilize the respiratory status of compromised patients by improving their oxygenation and ventilation. This technology has allowed us to safely transport patients to the operating room sooner to undergo surgical procedures. Methods A retrospective review was conducted of all VDR transports for surgery from January 2017 to May 2019. A total of eight patients were transported on the VDR to and from the OR on twenty-eight separate occasions. Patients presented with 19% to 73% TBSA burns with or without smoke inhalation. The population consisted of four males and four females, ranging in age from 21 – 61 years. Patients with severe burns and hypoxemia that failed conventional ventilation were placed on VDR. The VDR was initiated a minimum of 24 hours prior to surgery. Settings were optimized to achieve a PaO₂ of 60 mmHg or greater and a pH within 7.35–7.45 range. Patients were transported to the OR on VDR with a BICU Nurse, VDR technology trained Respiratory Therapist and a Burn Surgeon. Patients remained on the VDR throughout the entire operative case and were transported directly back to the BICU on the VDR. Results No difference was noted in EtCO2 or SpO2 with use of the VDR. A difference is PaO2 was noted with use of the VDR. Conclusions This study demonstrates that patients requiring VDR support can be safely transported to the OR. Critically ill burn patients who have refractory hypoxemia can undergo early surgical excisions and debridement. These timely surgical interventions can reduce the delay to surgery which could potentially lead to a negative impact on the patient’s outcome. Applicability of Research to Practice The use of VDR can lead to more timely surgical intervention and thus, the rate of infections and pulmonary injury can be studied.

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Introduction: We initiated a protocol for the escalation or de-escalation of ventilatory support for patients in our SICU in January, 2013. The respiratory therapists make all ventilator changes according to the protocol algorithms for oxygenation or ventilation. The protocol does not require individual orders to be entered into the electronic medical record provided the changes are compliant with the protocol. The therapists are required to document the changes in the ventilator settings in the respiratory flowsheet and the indication for the change in the progress note sections of the chart. A separate order is required for extubation or to escalate care from airway pressure release ventilation to volumetric (APRV) to volumetric diffusive respiration (VDR). Methods: During the first 3 months of the protocol, all ventilator changes were made with oversight by the faculty physician or the respiratory therapist team leader to identify any gaps or deficits not covered by the algorithms. We modified the protocol based on the feedback from the therapists and re-implemented its use. Over the next 3 months, we performed a prospective evaluation of 20% of all patients to determine whether the ventilator changes and documentation were made according to the protocol algorithms. Results: We identified a significant improvement in the rate of compliance with the protocol for ventilator changes from 82% in the first month to 88% in the second month to 90% in the third month (p < 0.05). Our rate of appropriate documentation in the progress note section remains unchanged 75, 72, and 72% over the last 3 months. We have identified 2 areas that resulted in most of the protocol violations for the past 3 months. These areas will be revised on the protocol to address the problems. Additionally, an educational program has been developed to improve documentation. Conclusions: We have successfully implemented a respiratory therapist-driven ventilator protocol in the SICU and created a compliance program that identified problems and developed solutions to address them.

Bi-caval dual lumen venovenous extracorporeal membrane oxygenation and high-frequency percussive ventilatory support for postintubation tracheal injury and acute respiratory distress syndrome

Bi-caval dual lumen venovenous extracorporeal membrane oxygenation (VV-ECMO) as a nonoperative approach to postintubation tracheal injury has not been described. We report the case of a 7-year-old boy who sustained a postintubation tracheal injury, developed acute respiratory distress syndrome from aspiration and viral pneumonitis, and was supported on bi-caval dual lumen VV-ECMO for 16 days until the trachea healed without surgical repair. Before ECMO decannulation, high-frequency percussive ventilation using a volumetric diffusive respiration ventilator was used for lung recruitment and airway clearance without disruption of the healed trachea. The use of ECMO to allow for lower mean airway pressure during initial healing and high-frequency percussive ventilation for lung recruitment and secretion clearance is a promising strategy to allow nonoperative tracheal injury repair in critically ill patients with multiple comorbidities.

High-frequency Percussive Ventilation for Airway Clearance in Cystic Fibrosis: A Brief Report

Exacerbations of cystic fibrosis (CF) lung disease are characterized by increased inspissation of abnormally viscid pulmonary secretions with resultant plugging of small airways, worsened ventilation/perfusion mismatch, and increased physiological deadspace. In this circumstance, hypoxic respiratory failure necessitating mechanical ventilation can be life-threatening. We present such a case of CF lung disease poorly responsive to conventional mechanical ventilatory strategies, in which high-frequency percussive ventilation (HFPV) using volumetric diffusive respiration mobilized copious amounts of inspissated pulmonary secretions and improved refractory hypoxia. Subsequent transient hypercarbia necessitated titrating ventilator parameters to return the PaCO(2) to baseline; the voluminous clearance of secretions and improvement in oxygenation were sustained. HFPV appears unique in its ability to function as a methodological continuum from noninvasive percussion to invasive percussive ventilation for airway clearance, a fundamental tenet of the CF treatment paradigm.

High-Frequency Percussive Ventilation With Systemic Heparin Improves Short-Term Survival in a LD100 Sheep Model of Acute Respiratory Distress Syndrome

We undertook an assessment of high-frequency percussive ventilation (HFPV) and systemic heparin on survival in our LD100 sheep model of smoke/burn-induced acute respiratory distress syndrome (ARDS). This was a prospective controlled outcomes study in a large animal critical care laboratory. ARDS was induced in 13 sheep by a combination of 48 cotton smoke breaths and 40% full-thickness cutaneous burn (LD100) followed by mechanical ventilation (15 ml/kg tidal volume). After meeting ARDS criteria (PaO2/FiO2 < 200), the sheep were divided into high-frequency percussive ventilation (HFPV; n = 7) or volume-controlled mechanical ventilation (VCMV; n = 6) groups. Both groups received systemic heparin to achieve an ACT 180-300 seconds. HFPV was managed with the Volumetric Diffusive Respiration Ventilator (Percussionaire Corp., Sandpoint, ID). The VCMV group was managed with up to 10 ml/kg tidal volume. Arterial blood gases and ventilator settings were monitored every 6 hours after onset of ARDS. HFPV did not affect sheep hemodynamics. Survival 84 hours after smoke and burn injury was significantly greater in the HFPV (7/7, 100%) compared with the VCMV group (3/6, 50%, P < .05). PaCO2 was significantly greater in VCMV group at 36, 48, and 72 hours after smoke and burn injury. PaO2/FiO2 after 36 hours of smoke and burn injury in the HFPV group was improved compared with the VCMV group, but no statistical difference was found. In the VCMV group, peak airway pressure was decreased to 19.7 +/- 2.2 cm H2O at 36 hours from 29 +/- 2.8 at 24 hours as the tidal volume changed from 15 ml/kg to 10 ml/kg and then gradually increased to 39 +/- 5.6 cm H2O at 72 hours. In the HFPV group, peak inspiratory pressure kept constant at a level of 30 cmH2O. In our smoke/burn-induced LD100 sheep model of ARDS, volume-controlled mechanical ventilation with systemic heparin achieved a 50% survival whereas HFPV with systemic heparin achieved 100% survival at 60 hours after the onset of ARDS.

Delivery of nitric oxide by high-frequency percussive ventilation: System design and evaluation

Background: Inhaled nitric oxide (NO) improves oxygenation in patients with acute respiratory distress syndrome (ARDS), and may act synergistically with high-frequency ventilation. High-frequency percussive ventilation (HFPV) has improved outcome in patients with inhalation injury. Thus, a system for NO delivery via HFPV would be desirable, but has not yet been described. Methods: A mechanical test lung was used for this evaluation. HFPV was delivered by means of a Volumetric Diffusive Respiration ventilator (VDR-4®). Spontaneous breaths were simulated by means of a lever arm attached to the bellows of the test lung. NO was instilled continuously at a constant rate into a side port between the sliding venturi of the VDR-4® and the endotracheal tube. Nitrogen dioxide (NO2) and NO levels were measured electrochemically via ports located at the front and back of the test lung. Expired gas was scavenged, and environmental NO2 levels were monitored. The ability of the system to provide constant NO levels, with NO2 levels less than 1 ppm, was evaluated across a full range of ventilator settings and NO concentrations. Results: Target NO concentrations were easily achieved at all ventilator settings, with the following exception. At a low-frequency rate of 8 breaths/min or less, increased variability in the NO concentration was observed at the front (but not at the back) sampling port. Also, at a low-frequency rate of 6 breaths/min or less, NO2 levels of 1.1–1.9 ppm were seen at the front sampling port only. Environmental levels of NO2 did not increase above baseline. Scavenging did not alter ventilator operation. Conclusions: Delivery of NO via HFPV can be safely performed within acceptable parameters, provided the low-frequency rate is greater than 6–8 breaths/min.

Effects of Volumetric Diffusive Respiration ( VDR ) on Cardiopulmonary Hemodynamics and Oxygenation in Dogs

Effects of Volumetric Diffusive Respiration ( VDR ) on Cardiopulmonary Hemodynamics and Oxygenation in Dogs