Relation of volume history of lungs to respiratory mechanics in anesthetized dogs

Mead, J.; Collier, Clarence R.

doi:10.1152/jappl.1959.14.5.669

Cited by 379 publications

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“…These factors have been major difficulties in the use of human material for the study of pulmonary mechanics by this method. Mcllroy (1952), and subsequently Mead and Collier (1959), showed that much of the variation of results from postmortem human material could be attributed more to a failure of standardization 534 of inflation techniques than to the use of necropsy material.…”

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confidence: 99%

Post-mortem studies of the semistatic volume-pressure characteristics of infants' lungs.

Fagan¹

1976

Thorax

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Fagan, D. G. (1976). Thorax, 31,[534][535][536][537][538][539][540][541][542][543]. Post-mortem studies of the semistatic volumepressure characteristics of infants' lungs. Semistatic air volume-pressure (V-P) loops were recorded from 172 isolated lungs obtained from infants and children at necropsy. Technically unsatisfactory V-P loop behaviour and the presence of pathological changes led to the exclusion of 98 lungs. A further 10 lungs were excluded as it was decided to study the period of growth up to 90 cm crown-heel length. A total of 64 left lungs remained which were designated 'normal'. Control data were collected in an attempt to quantify the effects of storage and variations in inflation technique. A maximum inflation pressure of +30 cmH2O was used as a standard Pmax. The resulting maximum inflation volume (Vmax) data showed a cubic relation to the crown-heel length which deviated from the values obtained by the use of in-vivo regression equations. The extent and pattern of the deviation suggest that the technical factors are not a major contributory cause, and other explanations are discussed.The low-pressure proportional data from the deflation limb of the V-P curve are plotted against the crown-heel length, and the resulting curve is analysed. There is a sharp fall in the proportion of Vm.a retained in the lung at +5 cmH2O and +2-5 cmH20 with increasing body length, but proportional volume at zero transpulmonary pressure follows the same growth-related pattern as Vmx..The semistatic volume-pressure (V-P) loop obtained by inflating and deflating a lung with air in steps is a well-recognized method of studying the basic pulmonary mechanics of the lung (von Neergaard, 1929;Radford, 1957;Mead, 1961).In its simplest form, the air V-P loop is obtained by inflating and deflating the lung at fixed intervals of either volume or pressure. Time is allowed for equilibration after each change. This technique produces the semistatic loop as opposed to the dynamic loop. It is called semistatic because the stress relaxation curve of the lung is such that no sharp equilibrium point is attainable. The equilibration time of 30 seconds is assumed by most workers to give a good approximation.The deflation limb of the dynamic V-P loop is a measure of the recoil of the lung and the flow capacity of air passages, while the semistatic loop gives a measure of the recoil force of the lungalone.The recoil force of the lung during deflation may be divided into forces due to tissue retractive power and forces due to surface tension. The high-pressure portion of the deflation limb is thought to be controlled by tissue forces, and the low-pressure portion by surface tension forces. The measurement of the semistatic V-P loop gives a measure of the function of both of these elements of the lung's retractive power.Studies of pulmonary mechanics using this technique are mainly performed on experimental animals' lungs as these are the only lungs which can be obtained under strictly controlled conditions. This is highly desirable in or...

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Post-mortem studies of the semistatic volume-pressure characteristics of infants' lungs.

Fagan¹

1976

Thorax

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“…To ensure consistent mechanics measurements across all subjects, sufficient equilibration to a mechanical steady state was allowed prior to Z rs measurement. Due to the inherent path-dependence of lung recruitment on volume history, the introduction of deep inflations was omitted as they are expected to increase the steady-state fraction of open lung (Mead and Collier, 1959). Computational models applied to Z rs data following intratracheal HCl instillation have predicted a parallel increase in both the pressure required to prevent small airways from collapsing as well as those required to re-recruit non-patent distal airways (Massa et al , 2008).…”

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confidence: 99%

Acute chlorine gas exposure produces transient inflammation and a progressive alteration in surfactant composition with accompanying mechanical dysfunction

Massa

Scott

Abramova

et al. 2014

Toxicology and Applied Pharmacology

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Acute Cl2 exposure following industrial accidents or military/terrorist activity causes pulmonary injury and severe acute respiratory distress. Prior studies suggest that antioxidant depletion is important in producing dysfunction, however a pathophysiologic mechanism has not been elucidated. We propose that acute Cl2 inhalation leads to oxidative modification of lung lining fluid, producing surfactant inactivation, inflammation and mechanical respiratory dysfunction at the organ level. C57BL/6J mice underwent whole-body exposure to an effective 60 ppm-hour Cl2 dose, and were sacrificed 3, 24 and 48 hours later. Whereas pulmonary architecture and endothelial barrier function were preserved, transient neutrophilia, peaking at 24 hours, was noted. Increased expression of ARG1, CCL2, RETLNA, IL-1b, and PTGS2 genes was observed in bronchoalveolar lavage (BAL) cells with peak change in all genes at 24 hours. Cl2 exposure had no effect on NOS2 mRNA or iNOS protein expression, nor on BAL NO3− or NO2−. Expression of the alternative macrophage activation markers, Relm-α and mannose receptor was increased in alveolar macrophages and pulmonary epithelium. Capillary surfactometry demonstrated impaired surfactant function, and altered BAL phospholipid and surfactant protein content following exposure. Organ level respiratory function was assessed by forced oscillation technique at 5 end expiratory pressures. Cl2 exposure had no significant effect on either airway or tissue resistance. Pulmonary elastance was elevated with time following exposure and demonstrated PEEP refractory derecruitment at 48 hours, despite waning inflammation. These data support a role for surfactant inactivation as a physiologic mechanism underlying respiratory dysfunction following Cl2 inhalation.

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“…to ensure full expansion and standardization of measurements. Manual hyperinflation was performed for 15 seconds every 10 minutes and prior to each measurement of compliance (Mead and Collier, 1959;Judd and King, 1967), and this prevented obvious collapse from occurring. In 16 sheep the chest was opened by a wide left antero-lateral thoracotomy, the left pleura was incised, and the right pleural cavity was opened in the midline anteriorly.…”

Section: Methodsmentioning

confidence: 99%

Effect of hypothermia on lung compliance

Deal¹,

Warden²,

Monk³

1970

Thorax

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The changes in pulmonary compliance have been studied under conditions of total body hypothermia. Five groups of sheep were used; two groups were controls-one for the effects of anaesthesia and the other for normothermic biventricular bypass. The third group was cooled using a femoro-femoral arterio-venous shunt to 20°-23°C. The fourth group was cooled to 15°C. and rewarmed using the Drew technique. The excised lungs of the remaining sheep were studied at 370 and 15°C. (fifth group). The controls showed little change in compliance. The cooled animals showed a decrease in compliance. In the group subjected to hypothermia by the Drew technique, the rewarming phase initially brought a return towards normal compliance. As the temperature rose to 24°-30°C. the improvement in compliance ceased and thereafter compliance decreased for two hours after rewarming. Histologically the lungs were normal. There was no compliance change caused by cooling the excised lungs.

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Relation of volume history of lungs to respiratory mechanics in anesthetized dogs

Cited by 379 publications

References 0 publications

Post-mortem studies of the semistatic volume-pressure characteristics of infants' lungs.

Post-mortem studies of the semistatic volume-pressure characteristics of infants' lungs.

Acute chlorine gas exposure produces transient inflammation and a progressive alteration in surfactant composition with accompanying mechanical dysfunction

Effect of hypothermia on lung compliance

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