Left Ventricular Compressions Improve Hemodynamics in a Swine Model of Out-of-Hospital Cardiac Arrest

Figures & data

Figure 1. (a) Experimental protocol timeline; (b) Detailed ACLS protocol timeline. ^*rhythm check; BLS: Basic Life Support; ALCS: Advanced Cardiac Life Support; Post Resusc: Post Resuscitation; VF: ventricular fibrillation; ROSC: return of spontaneous circulation; J: joules; CPR: cardiopulmonary resuscitation; FiO2: fraction of inspired oxygen; mg: milligram; kg: kilogram; Epi: epinephrine; Amio: amiodarone; prn: as needed; gtt: infusion.

Table 1. Baseline characteristics of animals

	LV (n = 13)	Standard (n = 13)
Size
Weight (kg)	29 (2.1)	30 (3.1)
Vertical distance from sternal notch to aortic root (cm)	6.0 (0.8)	6.2 (0.8)
Vertical distance from sternal notch to mid LV (cm)	11.3 (1.2)	11.8 (0.9)
Lateral distance from sternum to mid LV(cm)	2.7 (0.7)	2.9 (0.6)
Hemodynamics
HR (min^−1)	104 (28)	87 (23)
Aortic SBP (mmHg)	102 (13)	106 (15)
Aortic DBP (mmHg)	63 (12)	63 (14)
RA SBP (mmHg)	7.3 (8.7)	6.9 (6.8)
RA DBP (mmHg)	1.9 (8.7)	0.5 (6.3)
CPP (mmHg)	61 (15)	62 (14)
SpO2 (mmHg)	96 (4.4)	98 (1.8)
ETCO2 (mmHg)	42 (3.2)	43 (6.3)
cerebral rSO2(%)	67 (10)	65 (6.8)
renal rSO2(%)	66 (5.2)	68 (4.4)
Laboratory Values
pH	7.42 (0.04)	7.42 (0.04)
pCO2 (mmHg)	42 (3.6)	45 (13)
pO2 (mmHg)	210 (34)	230 (28)
Lactate (mg/dL)	1.1 (0.6)	0.9 (0.3)
HCO3 (mEq/L)	27 (1.6)	28 (6.3)
Base Excess (mmol/L)	2.7 (1.6)	1.7 (1.7)

Data presented as mean (SD). Kg: kilogram; cm: centimeter; HR: heart rate; SBP: systolic blood pressure; DBP: diastolic blood pressure; RA: right atrial; mmHg: millimeters of mercury; SpO2: peripheral capillary oxygen saturation; rSO2: regional oximetry; mg: milligram; dL: deciliter; mEq: milliequivalent; L: liter; mmol: millimole.

Table 2. Repeated-measures analysis of variance for hemodynamic and arterial blood gas variables

	LV	Standard	p-value
Hemodynamic Variables
Aortic SBP (mmHg)	71.6 (44.0)	45.1 (28.5)	0.005^*
Aortic DBP (mmHg)	27.3 (19.8)	18.1 (15.4)	0.013^*
RA SBP (mmHg)	8.2 (7.8)	3.7 (2.5)	0.004^*
RA DBP (mmHg)	5.5 (11)	4.9 (10)	0.876
CPP (mmHg)	21.8 (24.3)	13.2 (18.4)	0.116
SpO2 (%)	81.2 (10.8)	76.6 (16.9)	0.261
ETCO2 (mmHg)	37.0 (17.6)	26.2 (15.1)	0.0004^*
Cerebral rSO2(%)	39.6 (20.9)	33.6 (19.0)	0.378
Renal rSO2(%)	51.8 (51.7)	8.34 (6.23)	0.980
Arterial Blood Gas Variables
pH	7.26 (0.18)	7.32 (0.15)	0.027^*
pCO2 (mmHg)	53.3 (19.0)	41.6 (17.5)	0.001^*
pO2 (mmHg)	164 (97.7)	179 (108)	0.536
Lactate (mg/dL)	4.5 (3.3)	5.5 (3.9)	0.185
HCO3 (mEq/L)	20.1 (5.1)	20.3 (6.2)	0.842
Base Excess (mmol/L)	−4.3 (5.4)	−5.2 (7.7)	0.158

Data presented as mean (SD). LV: left ventricle; SBP: systolic blood pressure; DBP: diastolic blood pressure; RA: right atrial; mmHg: millimeters of mercury; SpO2: peripheral capillary oximetry; rSO2: regional oximetry; mg: milligram; dL: deciliter; mEq: milliequivalent; L: liter; mmol: millimole.

^* significant difference between LV and Standard groups during all time intervals of resuscitation; adjusted p-values for repeated measures ANOVA are reported.

Figure 2. Difference in mean coronary perfusion pressure between treatment groups. Standard error bars represent standard error of the mean. ^* signifies a significant difference between LV and Standard treatment groups (p < 0.05).

Table 3. Mean coronary perfusion pressure of animals that did and did not attain return of spontaneous circulation in each treatment group

	LV CPP	Standard CPP
ROSC	24.4 (27.0)	N/A
non-ROSC	15.5 (14.7)	13.2 (18.4)

Data presented as mean (SD). LV: left ventricle; CPP: coronary perfusion pressure; SD: Standard Deviation; ROSC: return of spontaneous circulation; N/A: Not applicable.

Table 4. Return of spontaneous circulation and short-term survival in each treatment group

	LV	Standard	p-value
ROSC	9 (69.2)	0 (0.00)	0.0005
Survival to 60 min	9 (69.2)	0 (0.00)	0.0005

Data presented as n (%). LV: left ventricle; ROSC: return of spontaneous circulation; min: minutes.

Fisher's exact test used to determine p-value.