TABLE 2.

Trans-endothelial and trans-epithelial Starling pressure gradients at end-expiration, with “safety factor” (point B in Figure 4) and after some degree of matrix fragmentation (point C in Figure 4).

	Trans-endothelial			Trans-epithelial
	Point B (W/D = 5.5)	Point C (W/D∼7.5)		Point B (W/D = 5.5)	Point C (W/D∼7.5)
Pcap*	9	9	Pint**	5.7	0
Pint**	5.7	0	Pliq alv#	∼0	−17
σ end##	0.85	0.5	σ epi##	0.85	0.5
Πcap**	26.8	14.7	Πint**	13.8	9.3
Πint**	13.8	9.3	Πliq alv	0	5
			γ	1	25
ΔP	4	9	ΔP	5.7	17
σΔΠ	−11.0	0.0	σΔΠ	−11.7	−2.15
Starling gradient	−7.0	6.3	Starling gradient	−6.0	14.85

This table reports the expected values for capillary, interstitial, and alveolar liquid hydraulic pressures (Pcap, Pint, and Pliq alv, respectively) as well as for capillary, interstitial, and alveolar liquid oncotic pressures (Πcap, Πint, and Πliq alv, respectively). Endothelial (σ endo) and epithelial (σ epi) protein reflection coefficients are also reported. In bold, hydraulic (ΔP) and oncotic (σΠP) pressure gradients and total Starling pressure gradient. Positive values of the Starling gradient at endothelial level indicate filtration into interstitium; negative values at epithelial level indicate alveolar reabsorption. From B to C (the phase corresponding to progressive fragmentation of the matrix), Pint returned to zero, suggesting loss of the physiological alveolar mechanical tethering interaction (Mead et al., 1970). Accordingly, from point C on, we considered Pint = Palv, as suggested by Glucksberg and Bhattacharya (1991).

Pressure values are expressed in cmH₂O; σ is a pure number. *From Hakim et al., 1993; **from Miserocchi et al., 1993; ^#calculated from Beck and Lai-Fook, 1983; ^##from Parker et al., 2006. Surface tension (γ), dyne/cm.