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Biomedical subjects

K H Lindner

Publications and source records attributed to K H Lindner.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effects of the AT1-selective angiotensin II antagonist, telmisartan, on hemodynamics and ventricular function after cardiopulmonary resuscitation in pigs.

The purpose of this study was to investigate the effects of the angiotensin II (ANG II) antagonist, telmisartan, on hemodynamics, myocardial function and myocardial blood flow during the postresuscitation phase in a porcine model of CPR and to compare these to saline. After 4 min of ventricular fibrillation and 5 min of closed-chest CPR, defibrillation was performed in 16 domestic pigs to restore spontaneous circulation (ROSC). Ten minutes after ROSC, animals were allocated to receive either the ANG II antagonist, telmisartan, at a dose of 1 mg/kg (n = 8) or saline (n = 8). Hemodynamics, myocardial function and myocardial blood flow were measured prearrest and at 5, 30, 90 and 240 min after ROSC. Using a Swan-Ganz catheter with a fast responding-thermistor and a micromanometer tipped catheter, right ventricular end-diastolic and end-systolic volume, right ventricular ejection fraction, left ventricular contractility were 67 +/- 6 ml (mean +/- S.E.M.), 42 +/- 4 ml, 38 +/- 2%, 2036 +/- 77 mmHg/s in the telmisartan group and 82 +/- 2 ml (P < 0.05), 59 +/- 3 ml (P < 0.01), 28 +/- 2% (P < 0.01), 1596 +/- 82 mmHg/s (P < 0.01) in the control group, at 240 min after ROSC. No significant differences in mean aortic and pulmonary artery pressure, cardiac index or myocardial blood flow between the two groups were found. We conclude that the ANG II antagonist telmisartan administered during the postresuscitation phase in pigs increases myocardial contractility without changing cardiac index, systemic vascular resistance, pulmonary vascular resistance, or myocardial perfusion.

Angiotensin Receptor Antagonists↗
PubMed1997

Synergistic effects of vasopressin plus epinephrine during cardiopulmonary resuscitation.

Both epinephrine (Epi) and vasopressin (VP) increase coronary perfusion pressure (CPP) when administered during cardiac arrest. Given their different mechanisms of action we tested the hypothesis that during cardiopulmonary resuscitation (CPR) a combination of VP plus Epi would be superior to either agent alone. Epi(40 microg/kg), VP(0.3 U/kg) and the combination of both agents were assessed in a porcine model of ventricular fibrillation (VF). Maximum CPP (diastolic aortic-right atrial pressures) during CPR was similar among the groups but the time course of action was different in each group: with Epi + VP the increase in CPP was significantly more rapid than with VP alone whereas the CPP remained significantly higher for a longer periods of time with VP or VP + Epi versus Epi alone. Left ventricular blood flow (ml/min per g) determined during CPR two min after drug administration was similar between groups: Epi 1.06 +/- 0.16; VP 0.82 +/- 0.26; Epi + VP 0.83 +/- 0.14 (P = N.S.). Post drug administration. 2 min, cerebral blood flow (ml/min per g) in the VP group (0.76 +/- 0.15) was more than two times higher compared with Epi alone (Epi:0.30 +/- 0.08, P < 0.01 versus VP) and Epi plus VP (Epi + VP:0.23 +/- 0.03, P < 0.01 versus VP). We conclude that combination of VP + Epi during cardiac arrest results in a more rapid rise in CPP when compared with VP alone and a more sustained elevation in CPP than observed with Epi alone. Thus, the synergistic effects of these two potent vasopressor agents may be of benefit during CPR.

Adrenergic Agonists↗
PubMed1997

Endobronchial vasopressin improves survival during cardiopulmonary resuscitation in pigs.

BACKGROUND: Intravenous administration of vasopressin during cardiopulmonary resuscitation (CPR) has been shown to be more effective than optimal doses of epinephrine. This study evaluated the effect of endobronchial vasopressin during CPR. METHODS: After 4 min of untreated ventricular fibrillation and 3 min of CPR, 21 pigs were randomized to be treated with 0.8 U/kg intravenous vasopressin (n = 7), 0.8 U/kg endobronchial vasopressin (n = 9), or an endobronchial placebo of normal saline (n = 5). Defibrillation was performed 5 min after drug administration to attempt return of spontaneous circulation. RESULTS: All animals in the intravenous and endobronchial vasopressin group were resuscitated successfully, but only two of five animals in the placebo group were. At 2 and 5 min after drug administration, coronary perfusion pressure in the intravenous and endobronchial vasopressin group was significantly higher than in the placebo group (50 +/- 10, 34 +/- 5 vs. 16 +/- 6 mmHg, respectively; and 35 +/- 10, 39 +/- 10 vs. 19 +/- 5 mmHg, respectively; P < 0.05). CONCLUSIONS: Endobronchial vasopressin is absorbed during CPR, coronary perfusion pressure is increased significantly within a short period, and the chance of successful resuscitation is increased in this porcine model of CPR. Endobronchial vasopressin may be an alternative for vasopressor administration during CPR, when intravenous access is delayed or not available.

Animals↗
PubMed1997

Regulation of beta 2-adrenergic receptors on mononuclear leukocytes in patients with acute ischemic heart disease.

OBJECTIVE: To investigate relationships between acute adrenergic stress, plasma catecholamine concentrations, and beta 2-adrenergic receptors. DESIGN: Prospective, descriptive study. SETTING: Emergency medical service at a university hospital. PATIENTS: Twenty-seven patients with out-of-hospital cardiac arrest (n = 11), myocardial infarction (n = 6), and angina pectoris (n = 10), and 12 control subjects. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Mononuclear leukocyte beta 2-adrenergic receptor density and affinity were measured in patients 15 mins after successful cardiopulmonary resuscitation and after the diagnosis of myocardial infarction or angina pectoris, respectively, and were measured as well in control subjects. Plasma concentrations of catecholamines, glucose, and lactate were simultaneously measured with heart rate and blood pressure. After cardiac arrest, the density of beta 2-adrenergic receptors (1858 +/- 188 sites/cell [p < .01]), plasma epinephrine concentration (31,990 +/- 14,526 pg/mL [174.6 +/- 79.3 nmol/L] [p < .01]), heart rate (100 +/- 6 beats/min [p < .01]), glucose concentration (14.9 +/- 0.8 mmol/L [p < .01]), and lactate concentration (10.9 +/- 0.6 mmol/L [p < .01]) were increased in patients compared with those values in healthy controls. CONCLUSION: Acute maximal stress, such as after cardiac arrest, is associated with an increase in the density of beta 2-adrenergic receptors on mononuclear leukocytes derived from patients after successful cardiopulmonary resuscitation.

Acute Disease↗
PubMed1997

Ultrastructural alterations in the right and left ventricular myocardium following multiple low energy endocardial countershocks in anesthetized dogs.

Both high energy transthoracic and direct epicardial defibrillation can result in RV and LV myocardial damage, but little is known about the damage due to defibrillation using an endocardial RV electrode. Furthermore, disturbances in postdefibrillation oxidative metabolism have been reported and may be caused by primary injury of mitochondrial integrity and function, but information about ultrastructural mitochondrial alterations is rare. We therefore studied, in 13 fox hounds, RV and LV ultrastructural alterations following multiple low energy endocardial countershocks. Using an ICD and an endocardial defibrillation system a median of 54 (43-74) countershocks with a cumulative energy of 1,558 J (844-2,141 J) was delivered. After termination of countershocks, RV and LV myocardium was examined by electron microscopy. In both ventricles, severe myocardial alterations were found, including swollen mitochondria, disruption of mitochondrial crests, and loss of integrity of the mitochondrial inner and outer membranes. At the first time a semiquantitative score, originally developed for postischemic injury, was successfully used to grade the postcountershock mitochondrial alteration, which showed a more pronounced damage in the RV (2.69 +/- 0.22 points) compared to the LV (2.18 +/- 0.22 P = 0.021). We conclude that even the use of endocardial lead systems with low energy countershocks may lead to severe mitochondrial damage, especially in the RV.

Animals↗
PubMed1997

Recent advances in cardiopulmonary resuscitation.

Mechanical and pharmacologic measures intended to increase blood flow to vital organs are the mainstay of therapy for patients in cardiac arrest. Several new cardiopulmonary resuscitation (CPR) techniques as well as novel devices and pharmacologic agents have been developed and tested since the first report of manual closed chested CPR over three decades ago. These recent mechanical and pharmacologic advances in the treatment of cardiac arrest are described. Some of these new techniques, devices, and drug therapies are presently undergoing clinical evaluation in patients in cardiac arrest. While many of these new methods and techniques have shown promise in small clinical trials in humans, none have yet to be found to be conclusively superior to manual closed chested CPR and treatment with standard pharmacologic agents.

Anti-Arrhythmia Agents↗
PubMed1997

Analysis of the ventricular fibrillation ECG signal amplitude and frequency parameters as predictors of countershock success in humans.

OBJECTIVE: The purpose of this study was to assess from the ventricular fibrillation ECG signal whether certain amplitude parameters, or frequency parameters derived using fast Fourier transform analysis, are predictive of countershock success (defined as a stable supraventricular rhythm following countershock). DESIGN: Retrospective, descriptive study. SETTING: Emergency medical service at a university hospital. PATIENTS: Twenty-six patients with out-of-hospital cardiac arrest, whose initial ECG rhythm was identified as ventricular fibrillation. METHODS AND RESULTS: In all patients, advanced cardiac life support was performed in the out-of-hospital setting and a semiautomatic defibrillator was used for countershock therapy and simultaneous on-line ECG recording. For each patient, ECG data were stored in modules in digitized form over a period of 20 min and analyzed retrospectively. Using fast Fourier transform analysis of the ventricular fibrillation ECG signal in the frequency range of 0.3 to 30 Hz (mean +/- SD), median frequency, dominant frequency, edge frequency, and amplitude were as follows: 5.17 +/- 1.05 Hz, 4.56 +/- 0.99 Hz, 10.74 +/- 3.46 Hz, and 1.33 +/- 0.44 mV before successful countershock (n = 20); and 4.21 +/- 1.17 Hz (p = 0.0034), 3.31 +/- 1.57 Hz (p = 0.0004), 9.46 +/- 2.93 Hz (p = 0.5390), and 1.15 +/- 0.69 mV (p = 0.0134) before unsuccessful countershock (n = 134). Using software filters to completely eliminate interference due to manual cardiopulmonary resuscitation from the ventricular fibrillation power spectrum, only amplitude remained statistically different (p < or = 0.03) in predicting countershock success. CONCLUSIONS: We conclude that in patients, median frequency, dominant frequency, and amplitude are predictive of countershock success in humans.

Electric Countershock↗
PubMed1997

Median fibrillation frequency in cardiac surgery: influence of temperature and guide to countershock therapy.

OBJECTIVE: This study was designed (1) to investigate the effects of normothermic and hypothermic perfusion on the median frequency of the fibrillating myocardium, and (2) to elucidate whether frequency-guided countershock therapy improves countershock success during the reperfusion phase of cardiac surgery. DESIGN: Prospective, randomized study. SETTING: University hospital cardiac surgery room. PATIENTS: Thirty patients (first part of the study) and 38 patients (second part of the study) scheduled for elective coronary artery bypass surgery. METHODS AND RESULTS: During cardiopulmonary bypass, ventricular fibrillation (VF) was induced at a core body temperature of 34.1+/-0.2 degrees C (normothermia) (n=15) or at a core body temperature of 29.8+/-0.2 degrees C (hypothermia) (n=15). Using fast Fourier transformation of the ECG signal, median fibrillation frequency was recorded continuously for a period of 120 s. At the end of surgery, countershock was performed as soon as VF was recognized on the ECG monitor (X Hz group; n=19) or countershock was not performed until median fibrillation frequency had increased to the threshold of at least 5 Hz (5 Hz group; n=19). Median fibrillation frequency in the normothermic fibrillation group was statistically higher than in the hypothermic group. In the X Hz and 5 Hz countershock group, median fibrillation frequency before the first countershock attempt was 3.6+/-0.2 Hz and 5.4+/-0.1 Hz (p<0.0001), respectively. In the X Hz group, six countershocks resulted in supraventricular rhythm, 10 in VF, two in electromechanical dissociation, and one in asystole. In the 5 Hz group, 16 countershocks resulted in supraventricular rhythm, two in VF, and one in asystole (p=0.008). CONCLUSIONS: During normothermia, median fibrillation frequency is significantly higher than during hypothermic perfusion conditions. During the reperfusion phase of cardiac surgery, countershock success rate is significantly higher when a threshold of at least 5 Hz had been reached before the first countershock attempt.

Coronary Artery Bypass↗
PubMed1997

Shed mediastinal blood in 500 elective cardiac surgery patients: is there enough for retransfusion routinely?

OBJECTIVE: Since an increased use of several blood salvaging measures has contributed to a reduction in perioperative blood loss and the requirement for banked blood in recent years, the aim of this study was to establish current postoperative drainage losses in order to evaluate whether homologous retransfusion may be a useful measure to reduce autologous transfusion in elective cardiac surgery. DESIGN/SETTING: This prospective clinical investigation was performed at a University Intensive Care Unit during the first six hours following cardiac surgery. PATIENTS: 373 men and 127 women undergoing elective cardiac surgery were investigated. MEASURES: The amount of shed blood was measured four and six hours postoperatively. RESULTS: The average blood loss was higher in men than in women both in all operations as a whole (men, four hours: 223+/-73 ml, six hours 270+/-95 ml; women, four hours: 156+/-25 ml, six hours 195+/-22 ml), in valve replacement (men, four hours: 299+/-87 ml, six hours 350+/-101 ml; women, four hours: 187+/-30 ml, six hours: 219+/-31 ml) and in coronary artery bypass grafting (men, four hours: 197+/-69 ml, six hours: 242+/-83 ml; women, four hours: 128+/-15 ml, six hours: 173+/-18 ml). A blood loss of 400 ml was exceeded in 13% of men after valve replacement four and six hours postoperatively. In all other groups, less than 8% of patients had a loss of more than 400 ml both after four and after six hours. CONCLUSIONS: Postoperative drainage losses in elective cardiac surgery patients are small and a measurable advantage from retransfusion seems to be unlikely. We therefore endorse the routine use of shed mediastinal blood retransfusion in these patients.

Blood Loss, Surgical↗
PubMed1996

Vasopressin administration in refractory cardiac arrest.

BACKGROUND: Successful outcomes after cardiopulmonary resuscitation remain disappointingly infrequent, in animal studies, administration of exogenous vasopressin during closed- and open-chest cardiopulmonary resuscitation has recently been shown to be more effective than optimal doses of epinephrine in improving vital organ blood flow. OBJECTIVE: To describe the clinical effects and outcomes of administering vasopressin to patients in cardiac arrest refractory to current medical therapies. DESIGN: Case reports. SETTING: University hospital. PATIENTS: 8 adults with in-hospital cardiac arrest. INTERVENTIONS: After intravenous epinephrine (administered according to American Heart Association guidelines) and defibrillation efforts had failed, patients in cardiac arrest who were having cardiopulmonary resuscitation received 40 U of vasopressin intravenously and then defibrillation. MEASUREMENTS: Return of spontaneous circulation and hospital discharge rates. RESULTS: After administration of vasopressin, spontaneous circulation was promptly restored in all patients. Three patients were discharged from the hospital with intact neurologic function; the other five lived for between 30 minutes and 82 hours. CONCLUSION: In the presence of ventricular fibrillation with severe hypoxia and acidosis, vasopressin seems to be more potent and effective than adrenergic vasopressors for restoring spontaneous cardiovascular function. These results do not justify the widespread use of vasopressin for refractory cardiac arrest. However, on the basis of these cases, further studies comparing vasopressin with epinephrine are warranted in an effort to improve the currently dismal prognosis of patients after cardiac arrest.

Adult↗
PubMed1996

Effects of epinephrine and vasopressin on median fibrillation frequency and defibrillation success in a porcine model of cardiopulmonary resuscitation.

OBJECTIVE: This study was designed to assess whether median frequency of ventricular fibrillation (VF) correlates with myocardial blood flow and defibrillation success during cardiopulmonary resuscitation (CPR) after epinephrine or vasopressin administration. METHODS AND RESULTS: After 4 min of VF and 3 min of CPR, 14 pigs received 0.045 mg/kg epinephrine or 0.4 U/kg vasopressin. Using radio-labeled microspheres, median myocardial blood flow during CPR before, and 90 s and 5 min after drug administration (DA) was 15.5 (12.6, 23.1; 25th percentile, 75th percentile), 26.4 (18.5, 29.1), 16.9 (14.9, 19.1) mL min-1 100 g-1, respectively, in the epinephrine, and 16.9 (15.4, 18.9), 48.1 (36.9, 68.9) (P < 0.05 vs. before DA), 52.3 (38.5, 65.0) mL min-1 100 g-1, respectively, in the vasopressin group. Using spectral analysis of VF, median frequency of VF was 11.0 (10.7, 11.8), 11.3 (9.6, 13.1), 10.2, (8.8, 11.4) Hz, respectively, in the epinephrine, and 10.1 (10.0, 10.5), 11.7 (11.1, 14.2) (P < 0.05 vs. before DA), 13.2 (11.5, 13.9) Hz, respectively, in the vasopressin group at the same points in time. Median frequency correlates significantly with myocardial blood flow in the epinephrine (n = 21); rs = 0.772; P < 0.001) and in the vasopressin group (n = 21; rs = 0.905; P < 0.001). Median fibrillation frequency before the first defibrillation was 13.0 (12.2, 13.2) Hz in resuscitated (n = 8) and 9.2 (8.3, 10.2) Hz (n = 6) in non-resuscitated animals (P < 0.01). CONCLUSIONS: We conclude that median frequency of VF reflects myocardial blood flow and the chance of successful defibrillation during closed-chest CPR after vasopressor treatment in a porcine model of VF.

Adrenergic Agonists↗
PubMed1996

Regulation of right atrial beta-adrenoceptors after cardiopulmonary resuscitation in pigs.

OBJECTIVE: to test the hypothesis that right atrial beta-adrenoceptors are down-regulated after CPR and administration of beta-adrenergic agents. METHODS: after 3 min of ventricular fibrillation and 3 min of cardiac massage, 6 pigs received adrenaline (45 micrograms/kg) intravenously before defibrillation. After restoration of spontaneous circulation, dopamine was given in order to maintain the mean arterial blood pressure stable. Right atrial beta-adrenergic binding sites were determined by an equilibration binding assay using (-)-125Iodocyanopindolol. RESULTS: plasma adrenaline (mean +/- S.E.M.) was 1.1 +/- 0.9 ng/ml (6.0 +/- 4.9 nmol/l) pre-arrest and increased to 63.8 +/- 45.8 (348.2 +/- 250.0 nmol/l) (P < 0.05) and 1034 +/- 344 ng/ml (5644 +/- 1878 nmol/l) (P < 0.05) during CPR before and after adrenaline administration. At points in time 30 and 120 min after successful CPR, plasma adrenaline was 2.4 +/- 0.5 and 1.3 +/- 0.3 ng/ml (13.1 +/- 2.7 and 7.1 +/- 1.6 nmol/l). Compared to pre-arrest, the density of high-affinity beta-adrenoceptors was 29.0 +/- 12.8 fmol/mg pre-arrest and was 69.4 +/- 21.6 and 84.2 +/- 16.7 fmol/mg (P < 0.05 vs. pre-arrest) 30 and 120 min after CPR. The density of low-affinity as well as of total binding sites was not significantly changed after CPR. CONCLUSIONS: it is concluded that markedly elevated plasma catecholamine concentrations after CPR and administration of adrenaline and dopamine do not lead to a decrease in the total density of beta-adrenoceptors but to an increase in high-affinity beta-adrenoceptors in right atrial cells.

Adrenergic beta-Agonists↗
PubMed1996

Spectral analysis of ventricular fibrillation and closed-chest cardiopulmonary resuscitation.

This study was designed to assess the interference by closed-chest cardiopulmonary resuscitation (CPR) on the ventricular fibrillation (VF) ECG signal in a porcine model of cardiac arrest and to elucidate which variable of VF spectral analysis reflects best myocardial blood flow and resuscitation success during CPR. Fourteen domestic pigs were allocated to receive either 0.4 U/kg vasopressin (n = 7) or 10 ml saline (n = 7) after 4 min of VF and 3 min of CPR. Using radiolabeled microspheres, myocardial blood flow was determined during CPR before, and 90 s and 5 min after, drug administration. Using spectral analysis of VF, the median frequency, dominant frequency, edge frequency and amplitude of VF were determined simultaneously and before the first defibrillation attempt. Using filters in order to specify frequency ranges, stepwise elimination of mechanical artifacts resulting from CPR revealed that at a frequency bandpass of 4.3-35 Hz, median fibrillation frequency has a sensitivity, specificity, positive and negative predictive value of 100% to differentiate between resuscitated and non-resuscitated animals. The best correlation between myocardial blood flow and fibrillation frequency was found at a median frequency range of 4.3-35 Hz. We conclude that spectral analysis of VF can provide reliable information relating to successful resuscitation. In this model after elimination of oscillations due to mechanical CPR, median fibrillation frequency best reflects the probability of resuscitation success.

Analysis of Variance↗
PubMed1996

Large-dose administration of 6% hydroxyethyl starch 200/0.5 total hip arthroplasty: plasma homeostasis, hemostasis, and renal function compared to use of 5% human albumin.

Within a daily dose of 20 mL/kg, medium-molecular hydroxyethyl starch (HES) is a safe and effective colloid for intravascular blood volume replacement. The effect of large doses on coagulation and renal function is unknown. We prospectively studied 41 patients undergoing total hip arthroplasty during the perioperative period. Inevitable blood loss was replaced with HES (HES group) or albumin (ALB group) in combination with packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets. Hemodynamic, oncotic, coagulation, and renal functions were compared initially, at the end of surgery, during the postoperative period (1, 3, and 6 h), and also with respect to the volume of colloid solution administered (1500, 2000, and 3000 mL). Total intake and output balances, as well as the costs of blood replacement therapy, were registered at the end of the study. We found differences in oncotic variables even at 6 h after surgery (total serum proteins [TSP]:HES 36.4 +/- 7.9 g/L versus ALB 55.6 +/- 6.1 g/L, P < 0.01; serum albumin:HES 25.5 +/- 5.3 g/L versus ALB 42.0 +/- 5.6 g/L, P < 0.01). Colloid osmotic pressure (COP) and hemodynamic, coagulation, and renal functions were comparable, as was total blood loss (HES 4247 +/- 2090 mL versus ALB 4051 +/- 2830 mL). Total requirements for colloid solutions (HES 35.9 +/- 7.4 mL/kg versus ALB 33.9 +/- 10.5 mL/kg), PRBC, FFP, or platelets were comparable, whereas total cost of blood replacement therapy was 33% less in the HES group. With respect to efficacy and side effects on coagulation and renal function, medium molecular HES is an appropriate and economic alternative to albumin at daily doses of up to at least 36 mL/kg.

Aged↗
PubMed1996

Effects of ventilation on hemodynamics and myocardial blood flow during active compression-decompression resuscitation in pigs.

BACKGROUND: Active compression-decompression (ACD) improves hemodynamics and vital organ blood flow during cardiopulmonary resuscitation. The effects of intermittent positive pressure ventilation (IPPV) on ACD have not been studied. This study was designed to compare the effects of ACD with and without IPPV on gas exchange, hemodynamics, and myocardial blood flow. METHODS: After 30 s ventricular fibrillation, 14 tracheally intubated pigs were allocated to receive either ACD combined with IPPV (ACD-IPPV) or ACD alone. In animals treated with ACD-IPPV, the lungs were ventilated using a servo ventilator. Animals treated with ACD received 100% oxygen by a reservoir but ventilation was not assisted. RESULTS: Minute ventilation (median) was 6.5 and 6.1 l/min after 1 and 7 min of ACD-IPPV, and was 4.2 and 1.6 l/min after 1 and 7 min of ACD. In contrast to ACD-IPPV, PaO2 was less and PaCO2 was greater with ACD. Mean arterial (53 and 40 mmHg; P < 0.05) and mean central venous pressure (25 and 14 mmHg; P < 0.01) were greater during ACD-IPPV as compared with ACD. After administration of epinephrine 0.2 mg/kg, myocardial blood flow increased only in ACD-IPPV treated animals, and 5 min after epinephrine administration, myocardial blood flow was greater during ACD-IPPV (33 ml.min-1.100 g-1) as compared with ACD (15 ml.min-1.100 g-1; P < 0.05). Restoration of spontaneous circulation could be achieved only in animals subjected to ACD-IPPV. CONCLUSIONS: Gas exchange was critically impaired during the late phase of ACD. Compared with ACD-IPPV, myocardial blood flow was less preserved with ACD and was too low to achieve restoration of spontaneous circulation.

Animals↗
PubMed1996

Effects of graded doses of vasopressin on median fibrillation frequency in a porcine model of cardiopulmonary resuscitation: results of a prospective, randomized, controlled trial.

OBJECTIVE: To assess the effects of graded doses of vasopressin vs. saline on median fibrillation frequency and defibrillation success in a porcine model of cardiopulmonary resuscitation. DESIGN: Prospective, randomized, controlled trial. SETTING: Animal laboratory in a university medical center. SUBJECTS: Twenty-eight domestic pigs (body weight between 26 and 31 kg), aged 12 to 14 wks. INTERVENTIONS AND MAIN RESULTS: After 4 mins of ventricular fibrillation and 3 mins of closed-chest cardiopulmonary resuscitation, the animals were allocated to receive either 0.2 U/kg of vasopressin (n = 7), 0.4 U/kg of vasopressin (n = 7), 0.8 U/kg of vasopressin (n = 7), or 10 mL of saline (n = 7, control group). Using radiolabeled microspheres, myocardial blood flow rates during cardiopulmonary resuscitation-before drug administration and 90 secs and 5 mins after drug administration-were as follows in the four groups (mean +/- SEM): 18.8 +/- 0.9, 17.2 +/- 1.1, and 14.6 +/- 1.4 mL/min/100 g in the control group; 17.8 +/- 2.2, 49.6 +/- 6.3 (p < .01 vs. control group), and 29.4 +/- 3.1 mL/min/100 g (p < .05 vs. control group) in the group receiving 0.2 U/kg of vasopressin; 17.1 +/- 1.0, 52.4 +/- 7.5 (p < .01 vs. control group), and 52.2 +/- 5.8 mL/min/100 g (p < .001 vs. control group) in the group receiving 0.4 U/kg of vasopressin; and 18.1 +/- 1.6, 94.9 +/- 9.2 (p < .001 vs. control group), and 57.2 +/- 6.3 mL/min/100 g (p < .001 vs. control group) in the group receiving 0.8 U/kg of vasopressin. Using spectral analysis, median frequencies of ventricular fibrillation-before drug administration and 90 secs and 5 mins after drug administration-were as follows in the four groups: 9.6 +/- 0.4, 8.5 +/- 0.8, and 7.2 +/- 1.0 Hz in the control group; 9.7 +/- 0.5, 12.9 +/- 0.8 (p < .01 vs. control group), and 12.7 +/- 0.8 Hz (p < .001 vs. control group) in the group receiving 0.2 U/kg of vasopressin; 10.3 +/- 0.2, 12.7 +/- 0.9 (p < .01 vs. control group), and 12.8 +/- 0.7 Hz (p < .001 vs. control group) in the group receiving 0.4 U/kg of vasopressin; and 10.0 +/- 0.9, 14.1 +/- 0.9 (p < .001 vs. control group), and 12.5 +/- 0.9 Hz (p < .001 vs. control group) in the group receiving 0.8 U/kg of vasopressin at the same points in time. Median frequency before the first defibrillation attempt was 12.3 +/- 0.4 Hz in the resuscitated animals (n = 19) and 8.2 +/- 1.2 Hz in the nonresuscitated animals (n = 9) (p < .001). CONCLUSIONS: This study contributes to the characterization of the effect of increasing global myocardial blood flow on median fibrillation frequency after administration of graded doses of vasopressin in a porcine model of ventricular fibrillation. Interventions such as vasopressor treatment that increase fibrillation frequency improve the chance of successful defibrillation.

Animals↗