Ignasi De Yzaguirre i Maura’s scientific contributions

Introduction and aims: The atmosphere in the abysses of the mountains of Garraf (Barcelona) have lower oxygen levels and higher CO2 concentrations with respect to normality. To evaluate the risk of speleological exploration in this area, we studied 19 cavers (14 men and 5 women) while performing controlled exercise in a hypercapnic, hypoxic and normobaric atmosphere (15.2 ± 0.8% of 299 O2 and 19,049 ± 299 ppmv of CO2). Methods: The study was performed in a laboratory through ergometry. Two identical tests were used: one in a standard atmosphere (NN) and another in a confined atmosphere (a hypoxic tent), with rarefied air (HH). The following parameters were monitored: electrocardiogram, heart rate, oxygen saturation of hemoglobin, lactate, capillary glycemia, and final blood pressure. Results: The volunteers had distinct symptoms during the test with rarefied air: heat sensation (100%), dizziness (47%), headache (3%), ocular pruritus (21%), hand tremor (16%), extrasystoles (16.5%), hypertonic blood pressure behavior (26%), tachycardia (158.5 ± 15.9 bpm in rarefied air versus 148.7 ± 15.7 bpm in normal air; p<0.0002). All participants showed reduced oxygen saturation (93.4 ± 3.4% in rarefied air versus 97.7 ± 9.92% in normal air; p<0.00004). Discussion: Wide individual variability was found in symptoms and the parameters studied. In view of the results of this study, we recommend that a threshold of 45,000 ppmv of CO 2 not be exceeded in speleological exploration. Likewise, fitness assessment should be performed in individuals planning to enter confined atmospheres, such as the caves and abysses of this mountain.

Introduction and aims: The atmosphere in the abysses of the mountains of Garraf (Barcelona) have lower oxygen levels and higher CO2 concentrations with respect to normality. To evaluate the risk of speleological exploration in this area, we studied 19 cavers (14 men and 5 women) while performing controlled exercise in a hypercapnic, hypoxic and normobaric atmosphere (15.2 ± 0.8% of 299 O2 and 19,049 ± 299 ppmv of CO2). Methods: The study was performed in a laboratory through ergometry. Two identical tests were used: one in a standard atmosphere (NN) and another in a confined atmosphere (a hypoxic tent), with rarefied air (HH). The following parameters were monitored: electrocardiogram, heart rate, oxygen saturation of hemoglobin, lactate, capillary glycemia, and final blood pressure. Results: The volunteers had distinct symptoms during the test with rarefied air: heat sensation (100%), dizziness (47%), headache (3%), ocular pruritus (21%), hand tremor (16%), extrasystoles (16.5%), hypertonic blood pressure behavior (26%), tachycardia (158.5 ± 15.9 bpm in rarefied air versus 148.7 ± 15.7 bpm in normal air; p<0.0002).All participants showed reduced oxygen saturation (93.4 ± 3.4% in rarefied air versus 97.7 ± 9.92% in normal air; p<0.00004). Discussion: Wide individual variability was found in symptoms and the parameters studied. In view of the results of this study, we recommend that a threshold of 45,000 ppmv of CO2 not be exceeded in speleological exploration. Likewise, fitness assessment should be performed in individuals planning to enter confined atmospheres, such as the caves and abysses of this mountain.

Introducció i objectius: En el massís del Garraf (Barcelona) els avencs tenen una atmosfera amb disminució d'oxigen i augment de CO2 respecte a la normalitat. Per valorar el nivell de risc en l'exploració d'aquestes cavitats varem estudiar a 19 espeleòlegs (14 homes i 5 dones) en realitzar un exercici controlat, en una atmosfera hipercàpnica, hipòxica i normobàrica (15,2 ± 0,8% d'O2 i 19.049 ± 299 ppmv de CO2). Mètodes: L'estudi es va realitzar en laboratori, mitjançant ergometria. Es van realitzar 2 tests, un en atmosfera normal (NN) i un altre idèntic realitzat en ambient confinat (tenda d'hipòxia), amb l'aire enrarit (HH). Es van monitorar els següents paràmetres: electrocardiograma, freqüència cardíaca, saturació d'oxigen de l'hemoglobina, lactat, glucèmia capil·lar i pressió arterial final. Resultats: Els voluntaris van presentar diferent simptomatologia durant la prova amb aire enrarit: Sensació de calor (100%), mareig (47%), cefalea (3%), pruïja ocular (21%), tremolor a les mans (16%), extrasístoles (16,5%), resposta hipertònica de la pressió arterial (26%), taquicàrdia (158,5 ± 159 batecs/min en aire enrarit enfront de 148,7 ± 15,7 batecs/min en aire normal; p < 0,0002). Tots van presentar una disminució de la saturació d'oxigen (93,4 ± 3,4% en aire enrarit enfront de 97,7 ± 9,92% en aire normal; p < 0,00004). Discussió: Es va observar una gran variabilitat individual en els símptomes i paràmetres estudiats. En vista dels resultats, es recomana no sobrepassar el llindar de 45.000 ppmv de CO2, en exploració espeleològica. Així mateix és convenient una revisió mèdica d'aptitud abans d'internar-se en atmosferes confinades, com són els avencs i coves del mencionat massís.