ABSTRACT
Objective:To explore the correlation between carotid blood flow and the parameters derived by pulse oximetry Plethysmographic waveform in cardiopulmonary resuscitation, so as to provide a new index for carotid blood flow monitoring in cardiopulmonary resuscitation.Methods:Seven male domestic pigs were utilized for cardiac arrest model through ventricular fibrillation induced by electrical stimulation. Eight minutes after cardiac arrest, artificial chest compression was given for 4 min, and epinephrine 20 μg/kg was injected intravenously at 2 min after chest compression. The compression frequency, compression depth, right carotid blood flow, pulse oximetry plethysmographic waveform, aortic pressure, right atrium pressure and end tidal carbon dioxide partial pressure were continuously monitored and recorded. From 30 s to 4 min after chest compression, the values of the mean right carotid blood flow, the area under curve (AUC) of pulse oximetry plethysmographic waveform, the mean perfusion index, the mean coronary perfusion pressure and the average end-tidal carbon dioxide partial pressure during 6 s before time point were calculated every 30 s. The correlations between right carotid blood flow and the AUC of pulse oximetry plethysmographic waveform and perfusion index were analyzed respectively.Results:Ventricular fibrillation was induced successfully in seven animals. There were no significant differences in the mean chest compression frequency and depth per min during 4 min of chest compression. Right carotid blood flow at 30 s after chest compression was (92.7±32.7) mL/min, and decreased to (48.5±23.5) mL/min at 1 min after chest compression ( P<0.05). There was no significant difference in blood flow before and after epinephrine injection ( P>0.05). The AUC of the blood oxygen plethysmographic waveform and perfusion index showed synchronous change trends with right carotid blood flow. Both coronary perfusion pressure and end-tidal carbon dioxide partial pressure showed different change trends with right carotid blood flow. There was a positive correlation between the right carotid blood flow and the AUC of blood oxygen plethysmographic waveform ( r=0.66, P<0.01), and also a positive correlation between right carotid blood flow and perfusion index ( r=0.57, P<0.01). Conclusions:Carotid blood flow is positively correlated with the AUC of blood oxygen plethysmographic waveform and perfusion index in a porcine model of cardiopulmonary resuscitation. Real-time monitoring of the two parameters derived by pulse oximetry plethysmographic waveform can reflect the changes of carotid blood flow to a certain extent.
ABSTRACT
Objective To study the changes in and correlations between the partial pressure of end-tidal carbon dioxide (PETCO2) and the coronary perfusion pressure during cardio-pulmonary resuscitation (CPR) based on the cardiac arrest dog models of ventricular fibrillation by electric shock. Methods 36 healthy dogs were evenly randomized into 3 groups including 4 minutes close-chest CPR(CCCPR) group, 4 minutes open-chest CPR(OCCPR) group, and 8 minutes OCCPR group. There were 12 dogs in each group, half male and half female. In the process of CPR, all parameters about PETCO2 and CPP were recorded. Results In the 4 minutes CCCPR group, the correlation coefficient between the CPP and the PETCO2 was 0.992 (P<0.05), which was in positive linear correlation. In the 4 minutes OCCPR group, the correlation coefficient between the CPP and the PETCO2 was 0.937 (P < 0.05), which also showed positive linear correlation. In the 8 minutes OCCPR group, the correlation coefficient between the CPP and the PETCO2 was 0.952 (P<0.05), and was also in positive linear correlation. The percentage of ROSC was 66.7(8/12) in the 4 minutes CCOPR group, 100%(12/12) in the 4 minutes OCCPR group and 58.3%(7/12) in the 8 minutes OCCPR group. There were statistical differences in CPP, PETCO2 between models with ROSC and without ROSC at 1, 2, 5, 10, 15 and 20 mins of CPR (all P<0.05). Conclusions This research shows that there is a close positive linear relationship between the coronary perfusion pressure and the PETCO2, and PETCO2 could be used to evaluate the prognosis of the CPR.
ABSTRACT
Objective To investigate the effects of spontaneous agonal respiration on coronary perfusion pressure (CPP) during untreated cardiac arrest (ventricular fibrillation) in swine model.Methods Ten male healthy domestic swines (25.0 ± 1.5) kg were anaesthetised,intubated and mechanically ventilated.The catheterizations were separately inserted into the right atrium and thoracic aorta to monitor aortic pressure (AOP) and right atrial pressure (RAP).A pacing electrode was inserted into the right ventricle to induce ventricular fibrillation (VF).VF was induced by intra-ventricular stimulation withalternating electric current and untreated for 8 minutes.AOP and RAP were recorded until respiratory activity ceased.The CPP before and after agonal respiration was calculated and analyzed by paired-sample T test.Results All animals presented with agonal respiration from 1 to 6 minutes after VF during the first attempt.The CPP was (7.18 ±4.22) mmHg at 1 sec before agonal respiration,(11.78 ±5.16) mmHg at 0 sec after agonal respiration,(8.75 t:4.38) mmHg at 5 sec after agonal respiration and (8.23 ± 4.55)mmHg at 6 sec after agonal respiration.The CPP at 0 sec after agonal respiration was higher than that before agonal respiration (t =-3.140,P =0.012).The CPP at 5 sec after agonal respiration was higher than that at 1 sec before agonal respiration (t =-2.828,P =0.020).There was no difference in CPP between at 6 sec after agonal respiration and at 1 sec before agonal respiration (t =-1.778,P =0.109).Conclusions Agonal respiration accompanies ventricular fibrillation.After agonal respiration,the coronary perfusion pressure is increased for 5 seconds being in favor of cardiaopulmonary resuscitation.
ABSTRACT
Objective Gasp was defined as a pathology respiration during cardiac arrest. This study was to investigate its effect on hemodynamics during CPR. Method Twelve domestic pigs, weighening (30 ± 1) kg,were anaesthetized. After tracheal intubation and mechanical ventilation, continuous respiratory variables were recorded. An artery catheter was inserted for reference blood samples and measuring aortic artery pressure (AOP).Right atrial pressure (RAP) and cardiac output (CO) were detected by Swan-Ganz catheter. Ventricular fibrillation (VF) was induced by programmed electrical stimulation instruments. After 4 minutes untreated VF, standard 30:2 CPR was done for 12 minutes and the parameters were recorded. Results pH, PaCO2 and lactic acid increased and PaO2 decreased progressively during CPR, whereas PaO2 was up to 50mmHg during the whole protocol. Gasps were observed in 10 animals, but weaken gradually; the left 2 animals with no gasp did not restore of spontaneous circulation (ROSC). Standard CPR could produce passive ventilation more than dead space (VD), but its tidal volume decreased gradually, which led to the percentage of rescue ventilation increased progressively. Positive correlations were found between CO, coronary perfusion pressure (CPP) and minute ventilation of gasps (MVg) (r was 0.736 and 0.721 respectively, both P ＜0.01); negative correlation were found between RAP and MVg (r= -0. 744, P ＜ 0.01). Conclusions Standard CPR could maintain 12 minutes oxygenation of body; compressions could produce enough passive ventilation more than VD; gasps were benefit to ROSC by increasing CO, CPP and decreasing RAP.