Kelly J. Tucker

Active compression-decompression resuscitation: A novel method of cardiopulmonary resuscitation

Chest compression is an important part of cardiopulmonary resuscitation (CPR), but it only aids circulation during a portion of the compression cycle and has been shown to only minimally increase blood flow to vital organs. The purpose of this study was to quantitate the short-term hemodynamic effects of CPR with a hand-held suction device that incorporates both active compression and decompression of the chest. The suction device was applied to the middle of the sternum and compared with standard manual CPR in eight nonventilated anesthetized dogs. Coronary perfusion pressure, systolic and diastolic aortic pressures, right atrial diastolic pressure, and the velocity time integral (an analog of cardiac output), which were obtained by means of transesophageal pulsed wave Doppler echocardiography from the main pulmonary artery, were measured every 30 seconds during CPR. Minute ventilation was measured over the last minute of each CPR technique. Both active compression-decompression CPR and standard CPR were sequentially performed for 2 minutes in random order 30 seconds after induced ventricular fibrillation. The CPR techniques consisted of 100 compressions per minute, with a compression depth of 1.5 to 2 inches and a 50% duty cycle. Coronary perfusion pressure, velocity time integral (cardiac output analog), minute ventilation, and systolic arterial pressure were all significantly improved by active compression-decompression CPR when compared with standard CPR. We conclude that active compression-decompression CPR is a simple technique that appears to improve coronary perfusion pressure, systolic arterial pressure, cardiac output, and minute ventilation in nonventilated animals when compared with standard CPR.(ABSTRACT TRUNCATED AT 250 WORDS)

Active compression-decompression. A new method of cardiopulmonary resuscitation. Cardiopulmonary Resuscitation Working Group.

OBJECTIVE To describe and compare with standard cardiopulmonary resuscitation (CPR) in humans a new form of CPR that involves both active compression and active decompression of the chest. DESIGN Patients in cardiac arrest in whom standard advanced cardiac life support failed were randomized to receive 2 minutes of either standard or active compression-decompression (ACD) CPR using a custom, hand-held suction device, followed by 2 minutes of the alternate technique. The ACD device was applied midsternum and used to perform CPR according to the guidelines of the American Heart Association: 80 compressions per minute, compression depth of 3.8 to 5 cm, 50% duty cycle, and constant-volume ventilation. Mechanical Thumper CPR was also compared in five patients. End-tidal carbon dioxide (ETCO2) concentrations and hemodynamic variables were measured. Transesophageal Doppler echocardiography was used to assess contractility, the velocity time integral (an analogue of cardiac output), and diastolic myocardial filling times. RESULTS Ten patients were enrolled. The mean +/- SD ETCO2 was 4.3 +/- 3.8 mm Hg with standard CPR and 9.0 +/- 3.9 mm Hg with ACD CPR (P less than .0001). Systolic arterial pressure with standard CPR was 52.5 +/- 14.0 mm Hg and with ACD CPR, 88.9 +/- 24.7 mm Hg (P less than .003). The velocity time integral increased from 7.3 +/- 2.6 cm with standard CPR to 17.5 +/- 5.6 cm with ACD CPR (P less than .0001), and diastolic filling times increased from 0.23 +/- .09 seconds with standard CPR to 0.37 +/- .12 seconds with ACD CPR (P less than .004). Mechanical Thumper CPR consistently underperformed both standard and ACD CPR. Minute ventilation obtained in four patients during ACD CPR without endotracheal ventilation was 6.6 +/- 0.9 L/min. After 1 hour of standard CPR failed, three of 10 patients randomized to ACD CPR rapidly converted to a hemodynamically stable rhythm following 2 minutes of ACD CPR. CONCLUSION ACD CPR is a simple manual technique that improved cardiopulmonary circulation in 10 patients during cardiac arrest. Although ACD CPR may have produced a return of spontaneous circulation in three patients refractory to standard measures, its impact on survival when used early in cardiac arrest remains to be determined.

Active compression-decompression resuscitation: Effect on resuscitation success after in-hospital cardiac arrest

Objectives. The purpose of this study was to test the hypothesis that active compression-decompression would improve resuscitation success in human subjects after cardiac arrest. Background. Active compression-decompression cardiopulmonary resuscitation is a new method that improves cardiopulmonary hemodynamic function in animal models and humans after cardiac arrest. Methods. We conducted a prospective randomized clinical trial in patients with in-hospital cardiac arrest. Patients were assigned to receive standard manual or active compression-decompression cardiopulmonary resuscitation. The primary study end points were spontaneous return of circulation, 24-h survival and survival to hospital discharge. Results. Fifty-three consecutive patients after cardiac arrest undergoing 64 resuscitation attempts were studied (30 women, 23 men; mean [± SD] age 71 ± 13 years, range 38 to 96). Spontaneous return of circulation was observed in 24 (47%) of 53 patients and was increased in patients receiving active compression-decompression compared with those receiving standard manual cardiopulmonary resuscitation (15 [60%] of 25 vs. 9 [32%] of 28, respectively, p = 0.042); 24-h survival was increased (12 [48%] of 25 vs. 6 [21%] of 28, respectively, p = 0.041); and there was a trend toward improved survival to hospital discharge (6 [24%]of 25 vs. 3 [11%]of 28, respectively, p = 0.198) when active compression-decompression was compared with standard manual cardiopulmonary resuscitation. Conclusions. Active compression-decompression cardiopulmonary resuscitation improves return of spontaneous circulation and 24-h survival after in-hospital cardiac arrest. Active compression-decompression cardiopulmonary resuscitation appears to be a beneficial adjunct to standard manual cardiopulmonary resuscitation.

Active compression-decompression resuscitation: Analysis of transmitral flow and left ventricular volume by transesophageal echocardiography in humans

OBJECTIVES This study was designed to test the hypothesis that active compression-decompression cardiopulmonary resuscitation increases transmitral flow and end-decompression left ventricular volume over levels achieved with standard manual cardiopulmonary resuscitation. BACKGROUND Recently, cardiopulmonary resuscitation incorporating active compression and decompression of the chest has been demonstrated to improve hemodynamic status in a canine model and in humans after cardiac arrest. METHODS The active compression-decompression device was applied midsternum in five consecutive patients and results compared sequentially (in random order) with those of standard manual cardiopulmonary resuscitation. Both techniques were performed at 80 compressions/min with a 1.5- to 2-in. (3.8 to 5.1 cm) compression depth and a 50% duty cycle. Transesophageal echocardiographic data obtained in each patient included the velocity-time integral of transmitral pulsed Doppler recordings and two-dimensional images of the left ventricle in the long-axis view. Planimetric volume measurements of the left ventricle were obtained at both end-compression and end-decompression. RESULTS No difference was observed in end-compression volume between the two techniques (p = 0.81). Increased end-decompression volume (active compression-decompression technique 81.3 +/- 12.5 vs. standard technique 69.4 +/- 10.8, p < 0.05), stroke volume (active compression-decompression technique 32.6 +/- 6.8 vs. standard technique 17.6 +/- 5.2, p < 0.05) and velocity-time integral of transmitral flow (active compression-decompression technique 15.8 +/- 4.3 vs. standard technique 7.8 +/- 2.3, p < 0.05) were found in the active compression-decompression group. The transmitral velocity-time integral was highly correlated with left ventricular stroke volume (r = 0.90). CONCLUSIONS Improved transmitral flow, end-decompression left ventricular volume and stroke volume are seen with active compression-decompression resuscitation, suggesting a biphasic cardiothoracic cycle of flow. Active decompression of the chest appears to be a beneficial adjunct to standard cardiopulmonary resuscitation.

Physiology of blood flow during cardiopulmonary resuscitation. A transesophageal echocardiographic study.

BackgroundThere are two competing theories of the mechanism of blood flow during cardiopulmonary resuscitation. The “cardiac pump” theory postulates that blood flows because the heart is squeezed between the sternum and the spine. The “thoracic pump” theory postulates that blood flows from the thorax because intrathoracic pressure exceeds extrathoracic vascular pressure and that flow is restricted to the venous-to-arterial direction because of venous valves that prevent retrograde flow at the thoracic inlet. To determine which mechanism is operative during actual cardiopulmonary resuscitation, 20 patients were imaged with transesophageal echocardiography during resuscitation. Methods and ResultsTransesophageal two-dimensional and pulse Doppler echocardiography was begun within 7 minutes of initiation of cardiopulmonary resuscitation. In the 18 patients who could be analyzed, the mitral valve opened during the release phase (diastole) and closed during the compression phase (systole) of cardiopulmonary resuscitation. Mitral velocity-time integral measured 8 ± 3 cm during diastole. There was compression of right and left ventricular cavities with significant reduction in measured left ventricular volume during cardiopulmonary resuscitation. In five patients, mitral regurgitation was present. ConclusionTransesophageal echocardiography performed during actual cardiopulmonary resuscitation showing mitral valve opening during cardiac release, reduction of ventricular cavity size with compression, and atrioventricular regurgitation support the cardiac pump theory of cardiopulmonary resuscitation. This study demonstrates the feasibility and usefulness of transesophageal echocardiography during cardiopulmonary resuscitation.

Active compression-decompression resuscitation: effects on pulmonary ventilation

This investigation was designed to test the hypothesis that active compression-decompression resuscitation is able to independently provide improved levels of minute ventilation when compared to high-impulse manual cardiopulmonary resuscitation (CPR). Eight adult beagles (10-15 kg) were studied after induction of ventricular fibrillation. Single 1-min CPR trials were performed while arterial blood gases and minute ventilation were monitored. ACD and high-impulse CPR were performed sequentially, in random order at compression rates of 120/min, 1.5- to 2.0-inch compression depth and 50% duty cycle. Minute ventilation averaged 3.6 +/- 0.77 1 during high-impulse CPR and increased to 4.9 +/- 0.88 1 during ACD CPR. No difference was observed in arterial blood pH, PCO2, or PO2 when ACD was compared to high-impulse CPR. We conclude that ACD CPR provides improved levels of minute ventilation when compared to high-impulse manual CPR in this canine model of cardiac arrest. Improved minute ventilation may contribute to the mechanism of improved cardiopulmonary hemodynamics reported in previous investigations of ACD CPR. Further investigation is warranted to determine the effects of ACD CPR on pulmonary ventilation in human subjects after cardiac arrest.

Usefulness of adenosine in augmenting ventricular preexcitation for noninvasive localization of accessory pathways

Adenosine was administered to test the hypothesis that it would maximize preexcitation and facilitate noninvasive localization of accessory pathways in 22 patients with suspected accessory pathway-mediated tachycardias. Twelve-lead electrocardiograms and 2-dimensional echocardiograms were recorded at baseline and during adenosine-augmented ventricular preexcitation to localize the accessory pathway. Phase analysis was performed on digitized 4-chamber and short-axis views using a first harmonic Fourier transformation. At baseline, 15 patients had manifest preexcitation. In 14 of these patients (93.3%), preexcitation became more prominent after adenosine. Four patients without preexcitation at baseline clearly had it after adenosine. In patients who had preexcitation in response to adenosine, the electrocardiogram correctly identified the accessory pathway locations in 18 of 19 patients at a regional level and was incorrect in 1 of 19 patients. Echocardiographic phase analysis correctly identified the accessory pathway location in all 17 patients, who had technically adequate studies, at a regional level. In conclusion, administration of adenosine accentuates preexcitation, allowing for more accurate electrocardiographic and echocardiographic accessory pathway localization.

Abnormal pulmonary artery pressure profile after cardiac transplantation : an exercise Doppler echocardiographic study

This study was designed to test the hypothesis that pulmonary artery pressure at rest and during exercise differs between patients with a transplanted heart and normal subjects and to determine the mechanisms responsible for the difference. Twenty-one patients who had undergone heart transplantation 1.5 to 27 months earlier without current evidence of acute cardiac rejection and 25 normal subjects were studied by exercise Doppler echocardiography. Systolic pulmonary artery pressure was higher at baseline in heart transplant patients than in normal subjects, at 31.6 +/- 9 mm Hg (mean +/- SD) versus 22.5 +/- 4, respectively (p = 0.0001). The increase in systolic pulmonary artery pressure with exercise was 1.4 times higher in heart transplant patients and correlated with pretransplantation pulmonary vascular resistances (r = 0.55; p = 0.01). In contrast, cardiac index at baseline or during exercise did not differ between the two groups. Diastolic parameters and ejection fraction at baseline or during exercise did not correlate with systolic pulmonary artery pressure. In conclusion, Doppler exercise echocardiography offers an alternative, safe method hemodynamic study of the transplanted heart. Although an abnormal increase in left ventricular filling pressure with exercise has been well documented, further studies are needed to investigate and characterize potential abnormalities in pulmonary vascular tone in the transplanted heart.

Segmental analysis of resting echocardiographic function and stress scintigraphic perfusion: Implications for myocardial viability

In 73 patients with coronary artery disease, we performed segmental analysis of resting two-dimensional echocardiography and stress thallium-201 single photon emission computed tomographic scintigraphy with 24-hour delayed imaging to test the hypotheses that (1) combined analysis of stress thallium-201 scintigraphy (with 24-hour redistribution) and echocardiography provides an evaluation of the viability of most myocardial segments; and (2) the severity of the scintigraphic perfusion abnormality in a given segment is equivalent to the severity of its echocardiographically determined functional impairment. Scintigraphy showed 14% of the 1168 segments analyzed to have fixed severe defects. Echocardiography showed 11% of the 1070 segments analyzed to be akinetic or dyskinetic. However, with combined analysis, only 62 (5%) segments showed no evidence of viability by either imaging technique. We conclude that in this group of patients, 95% of segments have evidence of viability by one of these two conventional imaging techniques.

Active compression decompression resuscitation: Effect on resuscitation success after in-hospital cardiac arrest

OBJECTIVES The purpose of this study was to test the hypothesis that active compression-decompression would improve resuscitation success in human subjects after cardiac arrest. BACKGROUND Active compression-decompression cardiopulmonary resuscitation is a new method that improves cardiopulmonary hemodynamic function in animal models and humans after cardiac arrest. METHODS We conducted a prospective randomized clinical trial in patients with in-hospital cardiac arrest. Patients were assigned to receive standard manual or active compression-decompression cardiopulmonary resuscitation. The primary study end points were spontaneous return of circulation, 24-h survival and survival to hospital discharge. RESULTS Fifty-three consecutive patients after cardiac arrest undergoing 64 resuscitation attempts were studied (30 women, 23 men; mean [+/- SD] age 71 +/- 13 years, range 38 to 96). Spontaneous return of circulation was observed in 24 (47%) of 53 patients and was increased in patients receiving active compression-decompression compared with those receiving standard manual cardiopulmonary resuscitation (15 [60%] of 25 vs. 9 [32%] of 28, respectively, p = 0.042); 24-h survival was increased (12 [48%] of 25 vs. 6 [21%] of 28, respectively, p = 0.041); and there was a trend toward improved survival to hospital discharge (6 [24%] of 25 vs. 3 [11%] of 28, respectively, p = 0.198) when active compression-decompression was compared with standard manual cardiopulmonary resuscitation. CONCLUSIONS Active compression-decompression cardiopulmonary resuscitation improves return of spontaneous circulation and 24-h survival after in-hospital cardiac arrest. Active compression-decompression cardiopulmonary resuscitation appears to be a beneficial adjunct to standard manual cardiopulmonary resuscitation.