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RESPIRAZIONE GLOSSOFARINGEA.
We report a part of the last article of the PhD Erika Schagatay on the "Diving and Hyperbaric Medicine" Vol. 39 No.2 June '09.at the end of the page, you can read also some abstract...
Here for you two version of this page: in English and in Italian.
Lung packing can also be used as a training method to increase lung volume, and is often combined with specific stretching monouvres (personal communications from divers 2004-2008), but the resulting increase in vital capacity (VC) from a specifically-designed training programme of six week in non-divers was only 3%. An effect of autoinflating the lungs is also that the alveolar surface will increase and the respiratory membrane will be thinner. Five minutes after lung packing, an increased TLC compared to before packing has been recorded suggesting a warm-up effect. However, normal lung compliance in apnoea divers was recently reported, suggesting this may not be a major mechanism for long-term increases in TLC.
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Il "Packing" polmonare può anche essere utilizzato come metodo di allenamento per incrementare il volume polmonare, e spesso è cmbinato con delle specifiche manovre di stretching (così come le è stato riferito da apneisti durante il quadriennio dal 2004 al 2008), ma la risultante della capacità vitale (VC) derivante da uno specifico programma allenante preparato apposta dalla durata di sei settimane su un gruppo di controllo di non apneisti, ha visto un incremento del solo 3%!| Un effetto dell'autoinflating dei polmoni, è anche il fatto che le superfici alveolari sono incrementate e che le membrane respiratorie sono più sottili. Cinque minuti dopo il "Paking" polmonare, un incremento del TLC compare prima che il sia stato registrato una specie di effetto di riscaldamento. |
A frequently used method to increase lung volume just before diving is "lung packing" or "glossopharyngeal breathing" manoeuvres. The breathing method was originally observed in paralyzed patients, and it does not involve normal respiratory muscles. The normal (total lung capacity) TLC is determinated by the maximal contraction of the inspiratory muscles, and the chest and lung recoil. By using the oral cavity and the tongue as a pump to repeatedly press down small volumes of additional air into lungs already filled to TLC the diver can increase TLC by up to 4 L. Apnoenic duration during rest will likely increase by the same number of minutes. One drawback of this manoeuvre is that the resulting increase in intrathoracic pressure will reduce venous return, resulting in syncope if the diver does not submerge in time. A large inspired lung volume may also to some extent attenuate the development of the oxygen-conserving cardiovascular diving response discussed below. Yet the likely net effect will be that the extra air volume will prolong apnoea, both by providing increased oxygen (O2) storage, and by diluiting the carbon dioxide (CO2) received from the blood.
Un metodo frequentemente utilizzato per incrementare i volumi polmonari prima di un'immersione sono le manovre indicate con il nome di "stivaggio polmonare" o di "respirazione glossofaringea". Questo metodo respiratorio, fu inizialmente utilizzato nei pazienti paralizzati, e non coinvolge i normali muscoli respiratori. La capacità totale è determinata dalla massima contrazione dei muscoli inspiratori, dalla gabbia toracica e dalla retrazione polmonare. Utilizzando la cavità orale e la lingua come una pompetta, si spinge, in maniera ripetitiva, aria aggiuntiva in un volume minore, incrementando così la capacità polmonare totale e portandola addirittura ad un volume maggiore di ben 4 litri. La durata dell'apnea durante la statica si incrementa di un calore pari ad un minuto per litro aggiunto. Uno dei punti sfavorevoli a questa manovra è dovuto al fatto che questo tipo di respirazione incrementa la pressione intratoracica riducendo il ritorno venoso che sfocia in una sincope se l'apneista non si immerge in tempo. Un lungo volume polmonare inspirato, può inoltre attenuare lo sviluppo della conservazione dell'ossigeno nel riflesso da immersione. Ma il robabile effetto netto è che il volume d'aria supplementare, prolungherà l'apnea, sia prevenendo un aumento di ossigeno che della diluizione della Co2 ricevuta dal sangue.
The Abstract:
[...] Breath-hold divers train and compete in maximal apnea performance. Glossopharyngeal inhalation (GI) is commonly used to increase lung volume above vital capacity (VC) prior to apnea. We investigated the hypothesis that this practice would increase apnea performance and relaxed airway pressure. Seven well-trained breath-hold divers performed maximal bouts of apnea at three different lung volumes (85% VC, VC and VC + GI) both at rest (dry static apnea) and during underwater swimming (dynamic apnea). Heart rate, apnea time and end tidal PCO(2) and PO(2) (P (ET) CO(2) and P (ET) O(2)) were recorded. In addition, relaxed airway pressure was measured after GI. Maximal GI increased lung volume by 1.59+/-0.57 l above VC and increased relaxed airway pressure to from 3.5+/-0.5 to 8.7+/-1.7 kPa. Dry static apnea time was higher at VC + GI (346+/-46 s) than at VC (309+/-38 s, P<0.05) and 85% VC (297+/-48 s, P<0.01). Likewise, dynamic apnea time was higher at VC + GI (97+/-27 s) than at VC (78+/-14 s, P<0.05) and 85% VC (71+/-17 s, P<0.05). P (ET) O(2) values reached 3.5+/-0.6 kPa at the end of dry static apnea bouts and this was not different from dynamic apnea when taking hydrostatic pressure at swimming depth into account (3.7+/-0.6 kPa, P=0.48). In conclusion, GI increases lung volume, relaxed airway pressure and apnea performance in well-trained breath-hold divers. [...]
[...] Competitive breath-hold divers use glossopharyngeal breathing in order to increase their performance. Glossopharyngeal inhalation (GI) increases the volume of air in the lungs above the total lung capacity, thereby increasing the volume of gas available for pressure equalization at great depth. The reverse procedure, glossopharyngeal exhalation (GE), is used to suck air out of the lungs at great depth when the lungs are compressed, thus providing air in the mouth for equalization of pressure in the middle ear. Five Swedish apnea athletes were tested. Their vital capacity (VC) and the volume of air exhaled after GI were measured with a turbine spirometer, while the residual volume (RV), and the volume of gas in the lungs following GE was determined using a helium dilution procedure. Thereafter subjects performed these maneuvers during magnetic resonance imaging (MRI) of the thorax. All subjects exhibited a higher VC + GI (7.8-11.9l) than VC (6.2-9.5l) and lower RV-GE (1.16-1.77l) than RV (1.37-2.40l). MRI revealed pronounced changes in the volume of intrathoracic blood, with a small heart and compressed vessels following GI and the opposite, i.e., enlarged vessels during GE. MRI also showed an invagination of the posterior wall of the trachea, in connection with GE in certain subjects. [...]
[...] One technique employed by competitive breath-hold divers to increase diving depth is to hyperinflate the lungs with glossopharyngeal breathing (GPB). Our aim was to assess the relationship between measured volume and pressure changes due to GPB. Seven healthy male breath-hold divers, age 33 (8) [mean (SD)] years were recruited. Subjects performed baseline body plethysmography (TLC(PRE)). Plethysmography and mouth relaxation pressure were recorded immediately following a maximal GPB maneuver at total lung capacity (TLC) (TLC(GPB)) and within 5 min after the final GPB maneuver (TLC(POST)). Mean TLC increased from TLC(PRE) to TLC(GPB) by 1.95 (0.66) liters and vital capacity (VC) by 1.92 (0.56) liters (P < 0.0001), with no change in residual volume. There was an increase in TLC(POST) compared with TLC(PRE) of 0.16 liters (0.14) (P < 0.02). Mean mouth relaxation pressure at TLC(GPB) was 65 (19) cmH(2)O and was highly correlated with the percent increase in TLC (R = 0.96). Breath-hold divers achieve substantial increases in measured lung volumes using GPB primarily from increasing VC. Approximately one-third of the additional air was accommodated by air compression. [...]
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