Jacek Kot - Academia.edu (original) (raw)

Papers by Jacek Kot

The aim of our study was the evaluation of a pressure prediction method, which was based on Taylo... more The aim of our study was the evaluation of a pressure prediction method, which was based on Taylor series. The pressure value was predicted basing on its past values, which were weighted by coefficients calculated according to the Taylor series approximation. The advantage of such approach was possibility of non-uniform pressure measurements. The main disadvantage was the assumption that the pressure was well approximated by a low degree polynomial. The weighting coefficients were deterministic and could be calculated only once for uniformly sampled data. The method was tested on a cosine type signal and on real pressure data obtained during monitoring patients. The results showed that the method might give good results only in the case of a low noise contents (a high value of SNR). It appeared that applying the presented method to a prediction of the pressure value based on real data gave poor results.

Journal of wound care, 2017

Ortopedia Traumatologia Rehabilitacja, 2015

High-pressure injection injury (HPII) is a rare severe hand trauma associated with high rates of ... more High-pressure injection injury (HPII) is a rare severe hand trauma associated with high rates of complications and amputations of the peripheral parts of the fingers and permanent hand dysfunction. Early detection and treatment are crucial as any delay may result in a considerable functional deficit of the affected limb or amputation. The rate of amputation following HPII is 48%. This case report aims mainly to present the problem of HPII and general standards of management of such injuries. The routine use of supportive treatment in hyperbaric chambers, in the absence of contraindications, is also encouraged.

Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc

International maritime health, 2012

Clear differences between professional and recreational deep diving are disappearing, at least wh... more Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) c...

International Maritime Health, 2015

Diabetologia …, 2004

STRESZCZENIE WSTĘP. Zapalenie kości często towarzyszy infekcjom w przebiegu zespołu stopy cukrzyc... more STRESZCZENIE WSTĘP. Zapalenie kości często towarzyszy infekcjom w przebiegu zespołu stopy cukrzycowej iw znacznym stopniu zwiększa zagrożenie amputacją kończyny. Nie ma zgodności na temat najlepszego sposobu leczenia tego powikłania. MATERIAŁ I ...

Diving and hyperbaric medicine, 2017

Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiati... more Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiating a partial retraction and correction of our paper: Mathieu D, Marroni A, Kot J: Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment. Diving Hyperb Med. 2017 Mar;47(1):24-32. We wish to make the following statement: "Regardless of the strict process of editing and proof-reading of tables included in the above-mentioned publication, we received some comments from readers which showed us that imperfect layout of Table 1 and incorrect layout of Table 2 changed significantly the conclusions which could be drawn from them. Table 1 described the relation between strength of recommendations given by the Jury of the Consensus Conference and the level of evidence based on the GRADE system. There should be a clear and straight relation showing that Level 1 "strong recom...

Journal of Chromatography B, 2017

A simple, fast, sensitive and accurate methodology based on a LLE followed by liquid chromatograp... more A simple, fast, sensitive and accurate methodology based on a LLE followed by liquid chromatography-tandem mass spectrometry for simultaneous determination of four regioisomers (8-iso prostaglandin F2α, 8-iso-15(R)-prostaglandin F2α, 11β-prostaglandin F2α, 15(R)-prostaglandin F2α) in routine analysis of human plasma samples was developed. Isoprostanes are stable products of arachidonic acid peroxidation and are regarded as the most reliable markers of oxidative stress in vivo. Validation of method was performed by evaluation of the key analytical parameters such as: matrix effect, analytical curve, trueness, precision, limits of detection and limits of quantification. As a homoscedasticity was not met for analytical data, weighted linear regression was applied in order to improve the accuracy at the lower end points of calibration curve. The detection limits (LODs) ranged from 1.0 to 2.1pg/mL. For plasma samples spiked with the isoprostanes at the level of 50pg/mL, intra-and interday repeatability ranged from 2.1 to 3.5% and 0.1 to 5.1%, respectively. The applicability of the proposed approach has been verified by monitoring of isoprostane isomers level in plasma samples collected from young patients (n=8) subjected to hyperbaric hyperoxia (100% oxygen at 280kPa(a) for 30min) in a multiplace hyperbaric chamber.

Diving and hyperbaric medicine, 2015

The integrated chain of treatment of the most severe clinical cases that require hyperbaric oxyge... more The integrated chain of treatment of the most severe clinical cases that require hyperbaric oxygen therapy (HBOT) assumes that intensive care is continued while inside the hyperbaric chamber. Such an approach needs to take into account all the risks associated with transportation of the critically ill patient from the ICU to the chamber and back, changing of ventilator circuits and intravascular lines, using different medical devices in a hyperbaric environment, advanced invasive physiological monitoring as well as medical procedures (infusions, drainage, etc) during long or frequently repeated HBOT sessions. Any medical staff who take care of critically ill patients during HBOT should be certified and trained according to both emergency/intensive care and hyperbaric requirements. For any HBOT session, the number of staff needed for any HBOT session depends on both the type of chamber and the patient's status--stable, demanding or critically ill. For a critically ill patient, th...

Onkologia W Praktyce Klinicznej, 2012

Przetoka przełykowo-skórna i infekcja zgorzelą gazową po protezowaniu przełyku u chorego z zaawan... more Przetoka przełykowo-skórna i infekcja zgorzelą gazową po protezowaniu przełyku u chorego z zaawansowaną chorobą nowotworową Oesophageo-cutaneous fistula and gas gangrene after oesophageal prosthesis insertion in patient with advanced cancer disease STRESZCZENIE Mężczyzna, 73-letni, obciążony niewydolnością krążenia i rakiem prostaty z przerzutami do wątroby, został przyjęty do hospicjum stacjonarnego z zapaleniem śródpiersia i przetoką przełykowo-skórną okolicy lewego stawu mostkowo-obojczykowego. Wcześniej choremu wycięto część przełyku z powodu przełyku Barreta i założono protezę z powodu pooperacyjnego zwężenia w miejscu zespolenia. Mężczyzna zgłosił się do szpitala z objawami niewydolności krążenia, bólami w klatce piersiowej i dusznością po 6 miesiącach od założenia protezy przełyku. W badaniu fizykalnym stwierdzono ropień okolicy podobojczykowej lewej, trzeszczący w badaniu palpacyjnym. Zmianę nacięto, ewakuując dużą ilość treści ropnej. W badaniu bakteriologicznym wymazu z rany obecne były laseczki zgorzeli gazowej i chorego poddano leczeniu tlenem hiperbarycznym.

PLOS ONE, 2015

Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) t... more Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects.

Diving and hyperbaric medicine, 2015

Many of the accepted indications for hyperbaric oxygen treatment (HBOT) may occur in critically i... more Many of the accepted indications for hyperbaric oxygen treatment (HBOT) may occur in critically ill patients. HBOT itself may cause a number of physiological changes which may further compromise the patient's state. Guidelines on the management of critically ill patients in a hyperbaric facility have been founded on the conclusions of the 2007 European Committee for Hyperbaric Medicine (ECHM) meeting. With regard to patient management, HBOT should be included in the overall care of ICU patients only after a risk/benefit assessment related to the specifics of both the hyperbaric centre and the patient's clinical condition and should not delay or interrupt their overall management. Neither patient monitoring nor treatment should be altered or stopped due to HBOT, and any HBOT effects must be strictly evaluated and appropriately mitigated. With regard to the hyperbaric facility itself, the hyperbaric chamber should be specifically designed for ICU patients and should be fully e...

The paper presents an analysis of correlation between heart rate (HR) and blood pressure (BP). Th... more The paper presents an analysis of correlation between heart rate (HR) and blood pressure (BP). The actual data were obtained from three female and one male. The systolic and diastolic blood pressure was measured with the invasive method in the radial artery. The correlation coefficient indicates only linear dependence, so the inverse of HR was also taken into account. Since the measurements can be corrupted by noise the moving average filtering and trend analysis for all data was done. The results of the correlation analysis of this filtered data were similar to results obtained for raw data. The observed correlation coefficient between HR and BP (systolic and diastolic) for whole available data seems a random number. However the short-term correlation is relatively large (about 0.5), but rather unpredictable, since even sign of the correlation coefficient is changing.

Clear differences between professional and recreational deep diving are disappearing, at least wh... more Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) c...

PLOS ONE, 2015

Saturation decompression is a physiological process of transition from one steady state, full sat... more Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window--also called inherent unsaturation or partial pressure vacancy--but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of decompression after saturation with nitrogen-based breathing mixtures.

PLOS ONE, 2015

The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of in... more The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.

The aim of our study was the evaluation of a pressure prediction method, which was based on Taylo... more The aim of our study was the evaluation of a pressure prediction method, which was based on Taylor series. The pressure value was predicted basing on its past values, which were weighted by coefficients calculated according to the Taylor series approximation. The advantage of such approach was possibility of non-uniform pressure measurements. The main disadvantage was the assumption that the pressure was well approximated by a low degree polynomial. The weighting coefficients were deterministic and could be calculated only once for uniformly sampled data. The method was tested on a cosine type signal and on real pressure data obtained during monitoring patients. The results showed that the method might give good results only in the case of a low noise contents (a high value of SNR). It appeared that applying the presented method to a prediction of the pressure value based on real data gave poor results.

Journal of wound care, 2017

Ortopedia Traumatologia Rehabilitacja, 2015

High-pressure injection injury (HPII) is a rare severe hand trauma associated with high rates of ... more High-pressure injection injury (HPII) is a rare severe hand trauma associated with high rates of complications and amputations of the peripheral parts of the fingers and permanent hand dysfunction. Early detection and treatment are crucial as any delay may result in a considerable functional deficit of the affected limb or amputation. The rate of amputation following HPII is 48%. This case report aims mainly to present the problem of HPII and general standards of management of such injuries. The routine use of supportive treatment in hyperbaric chambers, in the absence of contraindications, is also encouraged.

Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc

International maritime health, 2012

Clear differences between professional and recreational deep diving are disappearing, at least wh... more Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) c...

International Maritime Health, 2015

Diabetologia …, 2004

STRESZCZENIE WSTĘP. Zapalenie kości często towarzyszy infekcjom w przebiegu zespołu stopy cukrzyc... more STRESZCZENIE WSTĘP. Zapalenie kości często towarzyszy infekcjom w przebiegu zespołu stopy cukrzycowej iw znacznym stopniu zwiększa zagrożenie amputacją kończyny. Nie ma zgodności na temat najlepszego sposobu leczenia tego powikłania. MATERIAŁ I ...

Diving and hyperbaric medicine, 2017

Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiati... more Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiating a partial retraction and correction of our paper: Mathieu D, Marroni A, Kot J: Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment. Diving Hyperb Med. 2017 Mar;47(1):24-32. We wish to make the following statement: "Regardless of the strict process of editing and proof-reading of tables included in the above-mentioned publication, we received some comments from readers which showed us that imperfect layout of Table 1 and incorrect layout of Table 2 changed significantly the conclusions which could be drawn from them. Table 1 described the relation between strength of recommendations given by the Jury of the Consensus Conference and the level of evidence based on the GRADE system. There should be a clear and straight relation showing that Level 1 "strong recom...

Journal of Chromatography B, 2017

A simple, fast, sensitive and accurate methodology based on a LLE followed by liquid chromatograp... more A simple, fast, sensitive and accurate methodology based on a LLE followed by liquid chromatography-tandem mass spectrometry for simultaneous determination of four regioisomers (8-iso prostaglandin F2α, 8-iso-15(R)-prostaglandin F2α, 11β-prostaglandin F2α, 15(R)-prostaglandin F2α) in routine analysis of human plasma samples was developed. Isoprostanes are stable products of arachidonic acid peroxidation and are regarded as the most reliable markers of oxidative stress in vivo. Validation of method was performed by evaluation of the key analytical parameters such as: matrix effect, analytical curve, trueness, precision, limits of detection and limits of quantification. As a homoscedasticity was not met for analytical data, weighted linear regression was applied in order to improve the accuracy at the lower end points of calibration curve. The detection limits (LODs) ranged from 1.0 to 2.1pg/mL. For plasma samples spiked with the isoprostanes at the level of 50pg/mL, intra-and interday repeatability ranged from 2.1 to 3.5% and 0.1 to 5.1%, respectively. The applicability of the proposed approach has been verified by monitoring of isoprostane isomers level in plasma samples collected from young patients (n=8) subjected to hyperbaric hyperoxia (100% oxygen at 280kPa(a) for 30min) in a multiplace hyperbaric chamber.

Diving and hyperbaric medicine, 2015

The integrated chain of treatment of the most severe clinical cases that require hyperbaric oxyge... more The integrated chain of treatment of the most severe clinical cases that require hyperbaric oxygen therapy (HBOT) assumes that intensive care is continued while inside the hyperbaric chamber. Such an approach needs to take into account all the risks associated with transportation of the critically ill patient from the ICU to the chamber and back, changing of ventilator circuits and intravascular lines, using different medical devices in a hyperbaric environment, advanced invasive physiological monitoring as well as medical procedures (infusions, drainage, etc) during long or frequently repeated HBOT sessions. Any medical staff who take care of critically ill patients during HBOT should be certified and trained according to both emergency/intensive care and hyperbaric requirements. For any HBOT session, the number of staff needed for any HBOT session depends on both the type of chamber and the patient's status--stable, demanding or critically ill. For a critically ill patient, th...

Onkologia W Praktyce Klinicznej, 2012

Przetoka przełykowo-skórna i infekcja zgorzelą gazową po protezowaniu przełyku u chorego z zaawan... more Przetoka przełykowo-skórna i infekcja zgorzelą gazową po protezowaniu przełyku u chorego z zaawansowaną chorobą nowotworową Oesophageo-cutaneous fistula and gas gangrene after oesophageal prosthesis insertion in patient with advanced cancer disease STRESZCZENIE Mężczyzna, 73-letni, obciążony niewydolnością krążenia i rakiem prostaty z przerzutami do wątroby, został przyjęty do hospicjum stacjonarnego z zapaleniem śródpiersia i przetoką przełykowo-skórną okolicy lewego stawu mostkowo-obojczykowego. Wcześniej choremu wycięto część przełyku z powodu przełyku Barreta i założono protezę z powodu pooperacyjnego zwężenia w miejscu zespolenia. Mężczyzna zgłosił się do szpitala z objawami niewydolności krążenia, bólami w klatce piersiowej i dusznością po 6 miesiącach od założenia protezy przełyku. W badaniu fizykalnym stwierdzono ropień okolicy podobojczykowej lewej, trzeszczący w badaniu palpacyjnym. Zmianę nacięto, ewakuując dużą ilość treści ropnej. W badaniu bakteriologicznym wymazu z rany obecne były laseczki zgorzeli gazowej i chorego poddano leczeniu tlenem hiperbarycznym.

PLOS ONE, 2015

Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) t... more Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects.

Diving and hyperbaric medicine, 2015

Many of the accepted indications for hyperbaric oxygen treatment (HBOT) may occur in critically i... more Many of the accepted indications for hyperbaric oxygen treatment (HBOT) may occur in critically ill patients. HBOT itself may cause a number of physiological changes which may further compromise the patient's state. Guidelines on the management of critically ill patients in a hyperbaric facility have been founded on the conclusions of the 2007 European Committee for Hyperbaric Medicine (ECHM) meeting. With regard to patient management, HBOT should be included in the overall care of ICU patients only after a risk/benefit assessment related to the specifics of both the hyperbaric centre and the patient's clinical condition and should not delay or interrupt their overall management. Neither patient monitoring nor treatment should be altered or stopped due to HBOT, and any HBOT effects must be strictly evaluated and appropriately mitigated. With regard to the hyperbaric facility itself, the hyperbaric chamber should be specifically designed for ICU patients and should be fully e...

The paper presents an analysis of correlation between heart rate (HR) and blood pressure (BP). Th... more The paper presents an analysis of correlation between heart rate (HR) and blood pressure (BP). The actual data were obtained from three female and one male. The systolic and diastolic blood pressure was measured with the invasive method in the radial artery. The correlation coefficient indicates only linear dependence, so the inverse of HR was also taken into account. Since the measurements can be corrupted by noise the moving average filtering and trend analysis for all data was done. The results of the correlation analysis of this filtered data were similar to results obtained for raw data. The observed correlation coefficient between HR and BP (systolic and diastolic) for whole available data seems a random number. However the short-term correlation is relatively large (about 0.5), but rather unpredictable, since even sign of the correlation coefficient is changing.

Clear differences between professional and recreational deep diving are disappearing, at least wh... more Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) c...

PLOS ONE, 2015

Saturation decompression is a physiological process of transition from one steady state, full sat... more Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window--also called inherent unsaturation or partial pressure vacancy--but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of decompression after saturation with nitrogen-based breathing mixtures.

PLOS ONE, 2015

The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of in... more The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.