Uporabnost transkutanih senzorjev za zaznavanje spreminjanja intraabdominalnega tlaka

Kušar, Maša (author), Trotovšek, Blaž (mentor)

V raziskavi smo proučevali možnost uporabe transkutanih tipal mišične kontrakcije za merjenje intraabdominalnega tlaka. V raziskavo smo vključili 30 bolnikov, ki so bili med 27.6.2018 in 24.6.2019 zdravljeni v enoti intenzivne nege Kliničnega oddelka za abdominalno kirurgijo UKC Ljubljana. Intraabdominalni tlak smo merili z dvema posrednima metodama - s proučevano, transkutano metodo, ki vključuje uporabo tipal mišične kontrakcije, ter z uveljavljeno intravezikalno metodo merjenja hidrostatskega tlaka v sečnem mehurju. Meritev tlaka z intravezikalno metodo smo pri vsakem bolniku opravili osemkrat, izmenično v mirovanju in med izvajanjem Valsalvinega manevra. Transkutano meritev smo izvajali istočasno z merjenjem intravezikalnega tlaka in sicer neprekinjeno, ves čas trajanja intravezikalnih meritev. V izbranem matematičnem modelu sta amplituda signala mišičnega krčenja in debelina podkožnega maščevja statistično značilno povezani z intravezikalno izmerjeno vrednostjo intraabdominalnega tlaka (p < 0,0001 in p = 0,0008). Ob tem ti dve izbrani neodvisni spremenljivki pojasnita 41 % variabilnosti, naključni vpliv bolnika pa še dodatnih 44 % variabilnosti podatkov. Napovedi intravezikalno izmerjenih vrednosti intraabdominalnega tlaka, pridobljene iz tega modela, niso pristrane glede na dejansko izmerjene vrednosti (bias = -0,0667 mmHg), niso pa dovolj natančne (95 % meje ujemanja [-14,4 mmHg; 14,3 mmHg]). Ob transkutano izmerjenem intraabdominalnem tlaku 21 mmHg ali več je pozitivna napovedna vrednost za prisotnost intraabdominalne hipertenzije 0,86; negativna napovedna vrednost izmerjenega tlaka 20 mmHg ali manj je 0,62. Ob transkutano izmerjenem IAP 21 mmHg ali več, je pozitivna napovedna vrednost za prisotnost intraabdominalne hipertenzije III. ali IV. stopnje 0,14; negativna napovedna vrednost izmerjenega tlaka 20 mmHg ali manj pa je 0,96. V izbranem matematičnem modelu razlika med amplitudama signalov mišičnega krčenja v dveh zaporednih merjenjih in debelina podkožnega maščevja nista statistično značilno povezani z razliko med zaporednima vrednostima intraabdominalnega tlaka, pridobljenima z istočasno intravezikalno meritvijo (p = 0,06 in p = 0,65). Ob tem izbrani neodvisni spremenljivki pojasnita 13 % variabilnosti, naključni vpliv bolnika pa še dodatnih 79 % variabilnosti podatkov. Ob transkutano izmerjeni spremembi intraabdominalnega tlaka za 10 mmHg ali več je pozitivna napovedna vrednost za intravezikalno spremembo vsaj 10 mmHg 1; negativna napovedna vrednost izmerjene spremembe tlaka za manj kot 10 mmHg je 0,88. V raziskavi smo dokazali, da je signal tipala mišičnega krčenja statistično značilno povezan z intravezikalno izmerjenim intraabdominalnim tlakom. Pokazali smo, da s tipali mišičnega krčenja lahko merimo intraabdominalni tlak ter da aktivacija mišične trebušne stene ne moti meritev. Ujemanje med standardno, intravezikalno in proučevano, transkutano metodo merjenja intraabdominalnega tlaka trenutno sicer še ni dovolj veliko, da bi metodi lahko zamenljivo uporabljali. Neujemanje je vsaj delno posledica zasnove raziskave in omejitev standardne intravezikalne metode. V prvem koraku preizkušanja smo se želeli izogniti invazivnim metodam in vključitvi kritično bolnih preiskovancev. Kljub temu smo prikazali, da s tipali mišičnega krčenja lahko merimo intraabdominalni tlak. Rezultati raziskave so vsekakor dobra osnova za nadaljnji razvoj in izboljšavo tipal ter tudi za raziskave, ki bodo omogočile boljšo oceno njihove natančnosti.

• Language: Slovenian
• Keywords: intraabdominalni tlak, abdominalni utesnitveni sindrom, tipalo mišičnega krčenja
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2023
• PID: 20.500.12556/RUL-149074
• Publication date in RUL: 03.09.2023

Secondary language

• Language: English
• Title: Utility of transcutaneous sensors in intraabdominal pressure changes

Abstract

In this study we evaluated the possibility of using transcutaneous muscle contraction sensors to measure intra-abdominal pressure. The study was conducted between June 27 2018 and June 24 2019 and included 30 patients who were treated in the Department of abdominal surgery UMC Ljubljana. Intra-abdominal pressure was measured with two indirect methods - the proposed transcutaneous method, which involves the use of muscle contraction sensors, and the standard intravesical method of measuring the hydrostatic pressure within the bladder. In each patient, we measured the intravesical pressure eight times, 4 times at rest and 4 times while executing a Valsalva maneouvre. The transcutaneous measurement was conducted continuously for the entire duration of the intravesical measurements. In the chosen mathematical model, the amplitude of the muscle contraction signal and the thickness of subcutaneous fat are statistically significantly associated with the intravesically measured intra-abdominal pressure (p < 0,0001 and p = 0,0008). The chosen fixed effects explained 41 % of variability in data, while the random effect of patients explains an additional 44 % of variability. Intraabdominal pressure estimates, acquired from this model, are not biased in comparison to actually measured values (bias = -0,0667 mmHg), but they are not in agreement with the standard method (95 % limits of agreement [-14,4 mmHg; 14,3 mmHg]). With a transcutaneously obtained IAP measurement of 21 mmHg or more, the positive predictive value for the presence of intraabdominal hypertension is 0,86; the negative predictive value of transcutaneously measured values of 20 mmHg or less is 0,62. With a transcutaneously obtained IAP measurement of 21 mmHg or more, the positive predictive value for the presence of intraabdominal hypertension of degree III. or IV. is 0,14; the negative predictive value of measured values of 20 mmHg or less is 0,96. In the chosen model, the difference between the amplitudes of the muscle contraction signals in two consecutive time periods and the thickness of subcutaneous fat are not statistically significantly associated with the difference in intravesically measured values in those time periods (p = 0,06 and p = 0,65). The chosen fixed effects explained 13 % of variability in data, while the random effect of patients explains an additional 79 % of variability. With a transcutaneously obtained difference between two IAP measurements of 10 mmHg or more, the positive predictive value for the presence of such a change in IAP is 1; the negative predictive value of measured differences of less than 10 mmHg is 0,88. The study has shown that the signal amplitude of a muscle contraction sensor is statistically significantly associated with intravesically measured intraabdominal pressure. We have shown that MC sensors can be used to measure intra-abdominal pressure and that activation of the abdominal wall does not prevent the measurements. At this point in development, the agreement between the intravesical and transcutaneous methods is not sufficient for interchangeable clinical use. This lack of agreement is at least partly a consequence of the study design as well as the limitations of the standard intravesical method. In the first step of testing, we wanted to avoid invasive methods and the inclusion of critically ill patients. In spite of that, we have shown that muscle contraction sensors can be used to measure intra-abdominal pressure. These results are a good grounding for the further development of the sensors and also justify further studies that will allow a better assessment of the accuracy of the sensors.

• Keywords: intraabdominal pressure, abdominal compartment syndrome, muscle contraction sensor