The effect of a peptide-containing synthetic lung surfactant on gas exchange and lung mechanics in a rabbit model of surfactant depletion

Figures & data

Table 1 Results before bronchoalveolar lavage at 3 hours and 5 hours after surfactant treatment in twelve rabbits

Variable	Synsurf group (n = 4)	Exosurf group (n = 4)	Exosurf + Ca^2+ group (n = 4)
Weight (kg)	3.13 ± 0.56	2.95 ± 0.19	3.44 ± 0.24
Pre-VT (mL/kg)	10.08 ± 0.29	10.20 ± 0.58	10.03 ± 0.35
180 minutes	10.08 ± 0.17	9.85 ± 0.21	10.13 ± 0.19
300 minutes	10.05 ± 0.10	9.75 ± 0.24	9.93 ± 0.22
Pre-MABP (mmHg)	82.60 ± 4.07	92.40 ± 3.83	91.50 ± 7.51
180 minutes	89.50 ± 11.21	100.30 ± 6.99	93.25 ± 4.72
300 minutes	87.00 ± 15.12	96.75 ± 12.2	91.00 ± 14.67
Pre-PaO2 (mmHg)	499.70 ± 9.46	511.10 ± 17.38	509.30 ± 24.08
Post-	57.95 ± 14.90	53.25 ± 15.97	50.81 ± 18.30
180 minutes	152.30 ± 49.27	85.69 ± 25.85	109.90 ± 46.32
300 minutes	281.30 ± 47.64	74.25 ± 8.84	85.69 ± 32.56
Pre-a/A ratio	0.76 ± 0.02	0.77 ± 0.04	0.76 ± 0.03
Post-	0.09 ± 0.02	0.08 ± 0.02	0.08 ± 0.03
180 minutes	0.23 ± 0.07	0.13 ± 0.04	0.16 ± 0.07
300 minutes	0.42 ± 0.07	0.11 ± 0.01	0.13 ± 0.05
Pre-PaCO2 (mmHg)	40.69 ± 3.15	39.38 ± 6.26	36.19 ± 8.04
180 minutes	38.44 ± 4.99	38.63 ± 5.49	36.19 ± 4.99
300 minutes	36.75 ± 2.12	40.13 ± 4.18	38.81 ± 7.15
Pre-PetCO2 (mmHg)	14.25 ± 3.06	14.63 ± 3.09	13.88 ± 1.3
180 minutes	9.56 ± 1.88	10.13 ± 2.17	10.69 ± 0.94
300 minutes	9.75 ± 1.50	9.38 ± 1.44	9.75 ± 2.21
Pre-P(a-et)CO2 (mmHg)	26.44 ± 4.95	24.75 ± 6.15	22. 31 ± 7.07
Postlavage	43.50 ± 15.16	42.66 ± 8.67	42.88 ± 15.07
300 minutes	27.00 ± 2.60	30.75 ± 3.06	29.06 ± 8.58
Cdyn (mL/cm H2O/kg)
Prelavage	0.93 ± 0.16	0.98 ± 0.16	0.88 ± 0.17
Postlavage	0.47 ± 0.04	0.46 ± 0.05	0.42 ± 0.06
300 minutes	0.47 ± 0.01	0.42 ± 0.02	0.44 ± 0.06
Rawe
Prelavage	33.75 ± 3.59	45.25 ± 24.06	36.75 ± 11.03
Postlavage	53.50 ± 4.20	74.25 ± 25.93	59.25 ± 13.07
300 minutes	46.75 ± 11.33	72.00 ± 22.32	55.25 ± 9.85

Note: Data are shown as the means ± standard deviation.

Abbreviations: V_T, tidal volume; MABP, mean arterial blood pressure; PaO₂, arterial PO₂; PAO₂, alveolar PO₂; PaCO₂, arterial PCO₂; PetCO₂, end-tidal PCO₂; P(a-et) CO₂, arterial end-tidal PCO₂; Raw_e, expiratory airway resistance; C_dyn, dynamic respiratory compliance; a/A ratio, arterial/alveolar ratio.

Figure 1 Time profile for oxygenation in the rabbit groups, as reflected by the arterial PaO₂ and a/A ratio after surfactant administration.

Abbreviations: a/A, arterial/alveolar; PaO₂, arterial PO₂.

Figure 2 Time profile of pulmonary shunt after administration of surfactant in rabbit groups.

Figure 3 Compliance of the respiratory system: time-profile comparison of rabbit groups prelavage and after surfactant administration.

Abbreviation: C_dyn, dynamic respiratory compliance.

Figure 4 Time profile of (A) alveolar dead space/tidal volume ratio (V_Dalv/V_T), (B) dead space/tidal volume ratio (V_D/V_T), and (C) arterial end-tidal PCO₂ difference before and after surfactant administration.

Table 2 Relation between arterial/alveolar PO₂ ratio and dead-space components

Surfactant group	Variable	Correlation coefficients
		r	r^Citation2	P
Synsurf	VDalv	0.37	0.13	0.2704
	VDalv/VT	0.31	0.10	0.3510
	VDphys	0.94	0.88	0.0000
	VDphys/VT	0.90	0.80	0.0001
Exosurf	VDalv	0.49	0.24	0.0928
	VDalv/VT	0.31	0.10	0.2675
	VDphys	0.93	0.86	0.0000
	VDphys/VT	0.93	0.86	0.0000
Exosurf + Ca^2+	VDalv	0.60	0.36	0.0497
	VDalv/VT	0.58	0.33	0.0307
	VDphys	0.85	0.72	0.0006
	VDphys/VT	0.83	0.69	0.0009

Abbreviations: V_Dalv, alveolar dead space; V_Dalv/V_T, alveolar dead-space/tidal volume ratio; V_Dphys, physiologic dead space; V_Dphys/V_T, physiologic dead space/tidal volume ratio.

Table 3 Relation between arterial end-tidal PCO₂ difference and dead-space components

Surfactant group	Variable	Correlation coefficients
		r	r^Citation2	P
Synsurf	VDalv	0.88	0.78	0.0004
	VDalv/VT	0.87	0.75	0.0005
	VDphys	0.63	0.40	0.0382
	VDphys/VT	0.70	0.49	0.0172
Exosurf	VDalv	0.74	0.54	0.0096
	VDalv/VT	0.19	0.04	0.5788
	VDphys	0.51	0.26	0.1071
	VDphys/VT	0.35	0.13	0.2861
Exosurf + Ca^2+	VDalv	0.90	0.81	0.0002
	VDalv/VT	0.93	0.87	0.00003
	VDphys	0.74	0.55	0.0091
	VDphys/VT	0.81	0.66	0.0024

Abbreviations: V_Dalv, alveolar dead space; V_Dalv/V_T, alveolar dead space/tidal volume ratio; V_Dphys, physiologic dead space; V_Dphys/V_T, physiologic dead space/tidal volume ratio.

Halliday HL Speer CP Strategies for surfactant therapy in established neonatal respiratory distress syndrome Taeusch HW Surfactant Therapy for Lung Disease (Lung Biology in Health and Disease) New York Marcell Dekker 1995 443 459

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