The Effect of Resuscitation Technique and Pre-Arrest State of Oxygenation on Blood–Gas Values during Cardiopulmonary Resuscitation in Dogs

Large mongrel dogs were anesthetized, instrumented, and subjected to electrically induced ventricular fibrillation after breathing either 100% oxygen (O2) or 10% O2 and 90% nitrogen for 10 minutes before arrest. Four minutes after arrest, open chest cardiopulmonary resuscitation (CPR) or intermittent abdominal compression closed chest CPR was initiated and continued for 20 minutes, at which time defibrillation was attempted. Central arterial and mixed venous blood samples were collected serially for the measurement of pH, carbon dioxide partial pressure (PCO2), and O2 partial pressure (PO2), and calculation of bicarbonate concentration and base excess. Mixed venous blood was collected serially for the measurement of lactate concentration. Hemodynamically variable resuscitation techniques and pre-arrest hypoxia or hyperoxia did not significantly influence blood-gas values during CPR. Mixed venous lactate concentrations after 20 minutes of CPR were significantly higher when hypoxia preceded the arrest and when intermittent abdominal compression closed chest CPR was used for resuscitation. Mixed venous PCO2 was significantly higher than arterial PCO2 in all dogs during CPR but was not significantly different before arrest.     

Cardiopulmonary resuscitation: current recommendations

Early recognition of CPA is the key to its successful management. For resuscitation to be managed successfully, effective forward blood flow must be established at the onset of the arrest. In our clinical experience, we have found that the Doppler unit allows us to assess the effectiveness of cerebral perfusion better than any other method of blood pressure evaluation. If, by Doppler monitoring results, cerebral perfusion is found to be poor, blood flow may be mechanically improved by instituting high dose epinephrine therapy and interposed abdominal counter-pressure techniques. There is an understandable reluctance on the part of many veterinarians to enter the chest in the course of CPR. Unfortunately, this delay in performing internal compressions is often the reason that open-chest CPR is deemed ineffective by so many practitioners. If external chest CPR is not effective within 1 to 2 min (maximum) of its initiation, an emergency thoracotomy and direct cardiac massage should be performed. We know that perfusion pressure increases three to five times with open versus closed-chest CPR. This improvement in perfusion with direct cardiac massage is due, in part, to the absence of venous pressure elevations created during external chest compression. It follows that better coronary and cerebral blood flow will result in better resuscitation when direct cardiac massage is performed early. The "bottom line" in CPR is successful resuscitation of the patient with resultant good neurologic function. It is hoped that through the use of these techniques and new cytoprotective drugs, the survival rate will rise.     

Current developments in c ar diopulmonary resuscitation

As veterinary surgeons, we must all deal, on occasion, with an animal who has suffered a cardiac arrest. This article reviews the recent literature concerning cardiopulmonary resuscitation (CPR) and examines the suggestions recently put forward by the American Heart Association in their improved resuscitation protocol. These protocol modifications have been shown experimentally and clinically to improve cerebral and myocardial haemodynamics during closed chest cardiac massage. The ultimate goal of CPR must be not merely to resuscitate the patient in the short term, but to promote complete neurological recovery in the longer term. Prompt recognition of cardiac arrest and the immediate initiation of resuscitative measures play a major contributing role in a favourable neurological outcome. In addition to the familiar ABC system of basic cardiac life support, the use of a high dose adrenaline (0–2 mg/kg) is proposed as the best first line drug treatment in the arrested patient. This can be accompanied by abdominal wrapping and synchronous ventilation and chest compressions to optimise cerebral and myocardial blood flow. Calcium chloride and sodium bicarbonate should no longer be included in the early resuscitative efforts.     

Cardiopulmonary resuscitation with vasopressin in a dog

That endogenous vasopressin levels in successfully resuscitated human patients were significantly higher than in patients who died pointed to the possible benefit of administering vasopressin during cardiopulmonary resuscitation (CPR). Several CPR studies in pigs showed that vasopressin improved blood flow to vital organs, cerebral oxygen delivery, resuscitability and neurological outcome when compared with epinephrine. In a small clinical study, vasopressin significantly improved short-term survival when compared with epinephrine indicating its potential as an alternative pressor to epinephrine during CPR in human beings. As there was little clinical data available at that time, its recommended use was limited to adult human beings with shock-refractory ventricular fibrillation. In this report, we present the case of a dog in which the successful management of intraoperative asystolic cardiac arrest involved vasopressin. Unexpected cardiac arrest occurred during anaesthesia for the surgical removal of multiple mammary adenocarcinomata in a 11-year-old Yorkshire terrier. Despite an ASA physical status assignation of III, the dog was successfully resuscitated with external chest compressions, intermittent positive pressure ventilation and vasopressin (2 doses of 0.8 IU kg(-1)) and was discharged 3 days later without signs of neurological injury. We believe vasopressin contributed to restoring spontaneous circulation. It may prove increasingly useful in perioperative resuscitation in dogs.     

Usefulness of an auditory aid to improve chest compression rate accuracy during cardiopulmonary resuscitation

Objective

To assess compression rate accuracy among veterinarians and registered veterinary nurses (RVNs) without and with an audible aid.

Design

Prospective study with use of a canine CPR manikin.

Setting

Small animal teaching hospital.

Subjects

Thirty-six participants (20 veterinarians and 16 RVNs).

Interventions

Each participant completed the first 2-minute cycle of chest compressions without an auditory aid on a canine CPR manikin. Each participant was then randomized to 1 of 3 auditory aid groups (Group B: Bee Gees “Stayin’ Alive”; Group Q: Queen “Another One Bites the Dust”; or Group M: traditional metronome) and then completed a second 2-minute cycle of chest compressions with the instruction to synchronize their compression rate with the beat of the auditory aid. An accurate chest compression rate was defined as obtaining a rate between 100 and 120 compressions per minute (cpm).

Measurements and Main Results

Median number of compressions administered by participants during Cycle 1 for the first minute was 111 (range 88–140) and for the second minute was 107 (range 80–151), with 25 of 36 (69%) participants obtaining an accurate chest compression rate. Median number of compressions administered during Cycle 2 for the first minute was 110 (range 76–125) and for the second minute was 110 (range 72–125), with 34 of 36 participants (94%) obtaining an accurate chest compression rate. Participants were more likely to obtain an accurate chest compression rate when an auditory aid was present compared to without (McNemar's test; P = 0.013). Subgroup analysis suggested the auditory aid was beneficial in Groups Q and M but not Group B (Kruskal–Wallis with Dunn's post hoc testing; P = 0.014, P = 0.0455, and P = 0.5637, respectively).

Conclusions

An auditory aid was associated with improved chest compression rate accuracy. However, as the auditory aid was not beneficial for Group B participants, our findings suggest that some auditory aids are more helpful than others.     

Resuscitation attempts in a foal with sudden cardiac arrest in the early recovery period

A 3‐month‐old female Warmblood foal, weighing 150 kg, was presented to the Equine Clinic of the University of Hannover with a fracture of the ulna (type 5 fracture of the olecranon). Anaesthesia was induced with midazolam and ketamine after sedation with xylazine and maintained with isoflurane. Anaesthesia was uneventful until cardiac arrest occurred in the early recovery period. Cardiopulmonary resuscitation (CPR) was performed with chest compressions and electrical defibrillation. During resuscitation palpebral reflexes and spontaneous breathing returned but ventricular fibrillation could not be converted to sinus rhythm by transthoracic defibrillation of the heart by electrical shock.     

家蚕氟中毒后中肠NADPH-细胞色素P450还原酶和NADPH-细胞色素C还原酶活性的变化

为了探究家蚕对NaF的代谢机制,以家蚕耐氟品种T6和氟化物敏感品种734为材料,从5龄起蚕开始分别添食50、100、200、400 mg/kg NaF溶液处理后的桑叶,检测蚕体中肠微粒体酶液中的黄素蛋白NADPH-细胞色素P450还原酶(CPR)和NADPH-细胞色素C还原酶(CR)的活性变化。氟物化敏感品种734的4个NaF处理组第3天的中肠CPR活性低于对照组,其余时间几乎都高于对照组,400 mg/kg NaF处理组在第4天的CPR活性最高,且各NaF处理组的CPR活性差异显著(P<0.05);耐氟品种T6 NaF处理组和对照组的中肠CPR活性整体上呈先升后降的趋势,几乎都在第2天达到最高值,各组之间的差异不显著(P>0.05)。氟化物敏感品种734的4个NaF处理组的中肠CR活性呈现先升后降的趋势,而对照组呈下降趋势;耐氟品种T6的50、100、400 mg/kg NaF处理组在第1～2天的中肠CR活性呈明显下降趋势,之后的变化相对较小,对照组的CR活性仅在第3～4天略高于NaF处理组,而其余时间NaF处理组的CR活性较高。2个家蚕品种添食不同浓度NaF后的中肠CR活性差异均不显著(P>0.05)。试验结果显示,耐氟品种T6在NaF作用下中肠的CPR和CR活性变化范围(分别为对照组的0.4～2.0倍和0.3～2.9倍)远小于氟化物敏感品种734这2种酶的活性变化范围(分别为对照组的0.6～9.3倍和0.4～4.6倍)。初步推测CPR和CR与家蚕对氟化物代谢具有一定的关联。     

Intraosseous injection during cardiopulmonary resuscitation in dogs

Five mixed breed dogs were used to investigate the feasibility of femoral intraosseous injection during cardiac arrest. The intraosseous route was evaluated in the anaesthetised dogs after induction of cardiac arrest. Fluorescein dye was injected through pre-placed intraosseous catheters during cardiac massage. The dye was detected at the membrana nictitans five to 12 seconds later indicating successful transfer from the femoral marrow cavity to the systemic circulation during cardiopulmonary resuscitation (CPR). The clinical value of intraosseous injection during CPR is discussed and compared with the endotracheal administration of drugs.     

Successful cardiopulmonary resuscitation in an adult horse following cardiovascular collapse on recovery from general anaesthesia in the Trendelenburg position

Equine anaesthesia is associated with a high risk of perioperative morbidity and mortality, particularly in the recovery period. Cardiovascular collapse and cardiopulmonary arrest (CPA) have been reported to account for one-third of anaesthesia-related perioperative deaths in the horse. This case report describes the successful cardiopulmonary resuscitation of a healthy adult Thoroughbred mare that developed cardiovascular collapse and subsequent CPA following positioning in the recovery box after general anaesthesia in the Trendelenburg position. Cardiopulmonary resuscitation (CPR) was instigated and included thoracic compressions, intermittent positive pressure ventilation and adrenaline administered via the intravenous and intra-tracheal routes. Return of spontaneous circulation (ROSC) was detected 5 min and 50 s after the start of CPR. A stable stance was achieved approximately 100 min after ROSC. The mare was discharged from the hospital 3 days later with no known complications. To the authors’ knowledge, this is the first case report documenting CPA following general anaesthesia in the Trendelenburg position in a horse, with subsequent successful CPR. The precise cause of the CPA is unknown but a number of plausible hypothesis are discussed including hypoventilation and a Bezold-Jarisch reflex.     

Survival Following Cardiopulmonary Resuscitation in Dogs and Cats

Dogs and cats receiving cardiopulmonary resuscitation (CPR) were evaluated for factors leading to cardiac arrest and for survival following the procedure. One-hundred-thirty-five canine and forty-three feline patients seen at the University of California, Davis Veterinary Medical Teaching Hospital that received CPR between August 1987 and December 1991 were studied. Initial resuscitation attempts were unsuccessful in 72% of dogs and 58% of cats. Five dogs and one cat were still alive 3 days after CPR. Ultimately only four dogs and one cat were discharged from the hospital alive. These five patients with uniquely longer survival all had cardiac arrests associated with drug and/or anesthetic reactions.     

Cardiopulmonary effects of thoracoscopy in anesthetized normal dogs

Objective To evaluate the effect of an open‐chest condition on oxygen delivery in anesthetized dogs. Study design Prospective, controlled experimental study. Animals Eight clinically normal adult Walker Hound dogs weighing 25.6–29.2 kg. Methods Eight anesthetized dogs underwent an open‐chest operation after the insertion of thoracoscopy cannulae in the lateral chest walls . A Swan Ganz catheter was used to both measure hemodynamic parameters and obtain mixed venous blood samples for blood gas analysis. A dorsal pedal catheter was placed to both measure arterial blood pressure and obtain blood samples for blood gas analysis. Oxygen delivery index and oxygen extraction ratio were calculated. A randomized block anova for repeated measures was used to evaluate the effect of the treatment on hemodynamic and pulmonary parameters. Results Creation of an open chest did not significantly affect oxygen delivery index (DO₂I; p = 0.545). It induced a significant decrease in arterial oxygen partial pressure (PaO₂; p = 0.018) and arterial oxygen content (CaO₂; p = 0.025). It induced a significant increase in shunt fraction (p = 0.023), physiologic dead space (p = 0.015), and alveolar‐arterial oxygen difference (p = 0.019). Arterial partial pressure of carbon dioxide (PaCO₂; p = 0.766) and arterial hemoglobin oxygen saturation (SaO₂; p = 0.178) were not significantly affected. Diastolic (DPAP; p = 0.050) and mean (MPAP; p = 0.033) pulmonary arterial pressures were significantly increased by opening the chest. Other hemodynamic parameters were not significantly affected. Conclusions Opening the thoracic cavity is not detrimental to hemodynamic function and oxygen delivery in normal dogs, although impaired gas exchange does occur. Clinical relevance Close monitoring of patients is recommended during open‐chest thoracoscopy as adverse effects on gas exchange can contribute to hypoxemia.     

鲁中肉羊初生体尺体重的遗传参数估计

为估计鲁中肉羊初生重、体高、体长、胸宽、胸深、胸围和管围的遗传参数,利用2018年上半年出生的611只鲁中肉羊的初生体尺体重数据,采用AI-REML (Average information restricted maximum likelihood)算法,借助DMU软件分析以产羔数为固定效应、个体加性遗传效应为随机效应的多性状动物模型。结果表明:鲁中肉羊初生重、胸宽、胸深、体高、体长、胸围和管围的遗传力分别为0.16、0.10、0.22、0.44、0.43、0.46和0.52,各性状之间遗传相关为-0.517～0.773,表型相关为-0.197～0.503。说明鲁中肉羊初生重、胸宽和胸深为低遗传力性状,体高、体长、胸围和管围为中等遗传力性状。     

中蒙绒山羊主要生产性能比较分析

为比较分析内蒙古二郎山绒山羊与蒙古国棕色绒山羊主要生产性能的差异,每个品种选取60只绒山羊进行生产性能测定,并利用SAS软件和Excel进行统计分析。结果表明,二郎山绒山羊平均体斜长、胸围及产绒量极显著高于蒙古国棕色绒山羊（P〈0.01）,在平均绒细度和体重上,二郎山绒山羊显著高于蒙古国棕色绒山羊（P〈0.05）;2个品种绒山羊体高、体斜长、胸围与体重相关关系极显著（P〈0.01）,相关关系最大的是胸围;2个品种绒细度与产绒量之间呈正相关,但不显著（P〉0.05）,二郎山绒山羊绒长度与产绒量相关关系极显著（P〈0.01）。另外,2个品种绒山羊的体高、体斜长与绒长度之间存在负相关;蒙古国棕色绒山羊的胸围与绒长度之间也存在负相关。综合性能上,二郎山绒山羊品种优势比蒙古国棕色绒山羊明显。     

Electromyography of some respiratory muscles in the horse

To investigate activity in respiratory muscles, insulated wire electrodes were used to record electromyographic activity in the costal diaphragm and in the intercostal, serratus ventralis, internal abdominal oblique, transversalis and rectus abdominis muscles in conscious horses and in the same animals when anaesthetised. Electromyographic activity was related to respiratory phases as recorded by a stethograph around the chest wall. The costal diaphragm showed tonic and inspiratory activity in both conscious and anaesthetised animals. The principal muscle actively involved in expiration was the transversalis muscle. Intercostal muscle activity, and any increased activity in the second part of either inspiration or expiration recorded in the conscious animal, was absent under anaesthesia. The very marked tonic activity found in the serratus ventralis muscle in standing horses disappeared during anaesthesia. It was concluded that any stabilisation of the chest wall contributed by activity in the serratus ventralis and intercostal muscles in conscious, standing horses is greatly reduced during anaesthesia.     

Brain hypoperfusion post-resuscitation

Post-resuscitation brain hypoperfusion is an all too common problem following successful CPR in dogs and cats. The deterioration of neurologic status may occur, regardless of the clinician's ability to restore and maintain heart rate and rhythm, mucous membrane color, capillary refill time, and arterial blood pressure. New insight has been gained into the mechanisms responsible for post-resuscitation brain hypoperfusion, which has improved current treatment regimens and the development of new therapeutic modalities. Proper use of fluids (isotonic or hypertonic saline, oncotic solutions), diuretics, corticosteroids, and sedatives, combined with appropriate CPR techniques, can improve outcome. New drugs and therapeutic techniques offer exciting potential for the future limitation of this problem.     

Effects of body position and ventilation/compression ratios during cardiopulmonary resuscitation in cats

Eighteen cats were anesthetized and were randomly assigned to 2 groups (9 cats/group). Cardiopulmonary resuscitation (CPR) was performed on each cat, with the cat in dorsal (group 1) or lateral (group 2) recumbency, by administering 5 external cardiac compressions/1 interposed (diastolic) ventilation (American Heart Association [AHA] technique; n = 3 cats/technique), simultaneous compression and ventilation (SCV; n = 3 cats/technique), or SCV with 1 interposed (diastolic) ventilation every tenth compression (SCV/DV; n = 3 cats/technique). Fourteen of the 18 cats were resuscitated. Central aortic and venous pressures were determined concurrently with lead II electrocardiography. Arterial blood samples were collected during the base-line period (after pressure fluctuations had stabilized, with the cats spontaneously breathing room air), 2.5 minutes after the onset of arrest (defined as the cessation of aortic pressure fluctuations), and after 10 minutes of CPR. Arterial blood gas values during the base-line period or during the period of arrest were not significantly different between group-1 and group-2 cats. After CPR, arterial pH and bicarbonate values were not significantly different between groups or between technique categories. The PaCO2 values were significantly lower in cats resuscitated by SCV or by SCV/DV than in cats resuscitated by AHA (P less than 0.05). The PaO2 values were significantly (P less than 0.001) higher in group-2 cats than in group-1 cats and were significantly (P less than 0.001) different between each technique category, with cats resuscitated by AHA having the lowest PaO2 and cats resuscitated by SCV/DV having the highest PaO2. Body position, CPR technique, sex, weight, or arterial blood gas values after CPR were not predictors of successful resuscitation.     

Controversial issues in drug treatment during cardiopulmonary resuscitation.

The goal of advanced life support in CPR must be to restore and maintain respiratory and hemodynamic effectiveness, and to correct the underlying dysrhythmia. Optimal basic life-support techniques must be continued to meet these goals. Many drugs have been suggested in the treatment of cardiac arrest, but unfortunately, drug effects are inconsistent and resuscitation rates remain low. Epinephrine, atropine, lidocaine, bretylium, and naloxone remain important drugs for consideration in CPR in most animals with cardiac arrest. The best chance of survival remains in early recognition of animals susceptible to arrest and in treatment of the underlying cause.     

Supplementation to meet metabolizable protein requirements of primiparous beef heifers: II. Pregnancy and economics

Metabolizable protein (MP) requirements of spring calving heifers increase over the winter due to advancing gestation. The MP content of grazed winter forage is low, which may result in an MP deficiency. The objective was to compare the response of supplementing pregnant yearling heifers to meet MP requirements versus conventional CP supplementation. In 1997-98 and in 1998-99, pregnant, March-calving heifers (2,120 animals; 358 kg) at two locations of a commercial ranch in the Nebraska Sandhills, were used following breeding through calving as 2-yr-olds (cows). Heifers were randomly allotted to one of two supplementation treatments (about 265 heifers/treatment) each year at each of two locations (Ashby and Whitman, NE). Treatments were 1) supplementation to meet MP requirements (MPR) or 2) supplementation to meet CP requirements (CPR). Heifers grazed upland range and meadow and were offered supplements three times weekly from mid-September to mid- or late-February. Increasing amounts of meadow hay were fed from mid-December through calving. After supplementation ended in February, heifers were managed in one group at each location until the following October. Body weights and body condition scores were taken in September, February, and October. Two-yr-old pregnancy rates were determined via rectal palpation in October. Capital budgeting techniques were used to determine the economic return of supplementation strategies. There were no differences in BW (P = 0.41) or body condition score (P = 0.99) change during the winter among treatment groups across years and locations, but MPR cows were heavier (425 kg) than CPR cows (421 kg) at the time of 2-yr-old pregnancy testing (P = 0.07). Pregnancy rate was higher (P = 0.001) in the MPR (91%) compared to the CPR treatment (86%). Regression analysis showed that the response of the MPR treatment on pregancy rates tended to be negatively correlated with precalving body condition score (P = 0.11), body condition score loss over the winter (P = 0.07), and body condition score at weaning of the first calf (P = 0.08). The improvement in 2-yr-old pregnancy by supplementing to meet MP requirements improved the value of each bred heifer by 13.64 dollars. We conclude that balancing MP requirements during gestation may result in a subsequent increase in 2-yr-old pregnancy and increase the value of young females.     

不同日龄乌蒙凤鸡体尺与屠宰性能相关性与主成分分析

为研究乌蒙凤鸡的生长发育和生产性能,实验选择210、240、270、300日龄乌蒙凤鸡各60只(公母各半)进行体尺与屠宰测定,同时对其体尺与屠宰性能进行相关性与主成分分析.结果 表明:不同日龄公鸡的龙骨长、胸宽、胸深和骨盆宽存在极显著差异,不同日龄母鸡的胸宽、胸深和骨盆宽存在极显著差异.心脏重在210日龄与300日龄乌...