Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure

Cordioli, Ricardo Luiz; Park, Marcelo; Costa, Eduardo Leite Vieira; Gomes, Susimeire; Brochard, Laurent; Amato, Marcelo Britto Passos; Azevedo, Luciano Cesar Pontes

doi:10.1186/2197-425X-2-13

Intensive Care Medicine Experimental

Table 3 Hemodynamic and metabolic variables during the ventilatory modes studied

From: Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure

Variable	V_T = 6 mL/kg	RR = 30	HFPPV = 60	HFPPV = 90	HFPPV = 120	HFPPV = 150	HFOV	p value^a
Hemodynamic
Heart rate (bpm)	144 [125,165]	165 [124,182]	173 [144,181]	169 [130,189]	164 [128,196]	173 [142,196]	145 [122,155]	P = 0.210
Cardiac index (mL/kg/min)	138 [128,153]	126 [121,145]	145 [120,169]	127 [115,158]	141 [118,166]	132 [116,168]	126 [101,142]	P = 0.363
SV (mL)	28 [26,42]	27 [24,41]	27 [26,35]	26 [23,44]	27 [26,34]	30 [26,35]	31 [22,44]	P = 0.916
ABPm (mmHg)	90 [75,107]	86 [75,112]	84 [72,97]	91 [77,100]	83 [70,112]	78 [69,105]	82 [72,98]	P = 0.320
PAPm (mmHg)	43 [38,52]	34 [31,37]^b	34 [28,36]^b	36 [33,37]^b	33 [30,47]^b	38 [30,43]^b	31 [30,40]^b	P = 0.018
CVP (mmHg)	9 [9,12]	8 [7,12]	8 [6,10]	9 [6,10]	8 [7,10]	9 [7,10]	11 [10,12]^c	P = 0.017
PAOP (mmHg)	12 [11,15]	12 [11,15]	12 [9,14]	12 [10,14]	12 [10,15]	12 [10,15]	14 [12,17]	P = 0.042
SvO₂ (mmHg)	54 [47,70]	70 [49,79]	68 [48,71]	63 [48,66]	64 [43,74]	65 [55,73]	65 [50,75]	P = 0.140
SVRI (dynes.s^-1(cm⁵)^-1.kg^-1	51.8 [41.8,56.4]	47.1 [39.8,65.6]	47.0 [35.0,50.9]	52.7 [36.7,61.4]	41.7 [33.4,63.6]	42.4 [28.8,66.5]	50.4 [31.6,55.8]	P = 0.558
PVRI (dynes.s^-1.(cm⁵)^-1.kg^-1	22.3 [17.5,25.7]	15.7 [13.0,16.8]	15.6 [10.9,17.7]	16.7 [13.9,17.7]	14.2 [12.4,20.8]	16.8 [12.0,20.7]	13.6 [10.9,18.2]	P = 0.133
Metabolic
Lactate (mEq/L)	1.7 [1.1,2.1]	1.3 [0.8,1.7]	1.6 [0.8,2.0]	1.7 [1.1,2.0]	1.4 [1.0,1.9]	1.6 [0.9,2.3]	1.5 [1.1,1.8]	P = 0.762
pH	7.13 [7.08,7.2]	7.25 [7.24,7.33]^b	7.25 [7.24,7.35]^b	7.26 [7.23,7.33]^b	7.27 [7.2,7.3]^b	7.26 [7.21,7.34]^b	7.25 [7.2,7.32]^b	P = 0.002
Temperature (°C)	38.6 [37.3,39.2]	39.7 [38.0,39.8]^b	39.4 [37.6,39.6]^b	39.2 [38.1,39.6]^b	38.8 [37.6,39.6]^b	39.0 [37.8,39.5]^b	39.2 [38.1,39.8]^b	P = 0.007
Fluid balance (mL)	−50 [−242,−5]	170 [101,278]	40 [−22,102]	100 [67,110]	60 [5,108]	40 [−58,88]	30 [−21,50]	P = 0.044

Values are presented as median [P25th,P75th]. ^aThe p value was obtained through Friedman’s test; ^bStudent-Newman-Keuls’ post hoc analysis, p < 0.05 vs V_T = stabilization step (V_T = 6 mL/kg and RR = 35 breaths/min); ^cStudent-Newman-Keuls’ post hoc analysis, p < 0.05 vs HFPPV = 150.

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