| Summary: | 碩士 === 國立中興大學 === 獸醫學系 === 87 === Background：Severe hemorrhagic shock (HS) is associated with high mortality both in human and veterinary, operating and emergency room. Numerous studies have reported about the cardiopulmonary effect of various sympathomimetic drugs. Vasopressors are often used to restore a minimal perfusion pressure and inotropic agents are often used to increase myocardial contractility. Different adrenergic drugs, mechanisms, doses, single or combined uses have different cardiovascular effects. However, optimal adrenergic support remains controversial. The purpose of this study is to examine the hemodynamic effects of different sympathomimetic drugs in hemorrhagic shock dogs.
Method：A total of 40 mongrel dogs were anesthetized with halothane and assigned to five groups. Following baseline measurement, the dogs were bled to a mean arterial pressure of 40 mmHg for 30 minutes. Each group was resuscitated with crystalloid solution and four groups with additional drugs. Epinephrine (EPI) (0.3mg/kg/min), norepinephrine (NE) (0.5mg/kg/min), dopamine (DP) (10mg/kg/min) and dobutamine (DOB) (10mg/kg/min) were given, and each drug was infused for 30 minutes followed by a interval of 30 minutes without medication. Hemodynamic monitoring data were obtained at 5 different time points ( control, shock, 2.5 and 30 minutes during resuscitation and 30 minutes after resuscitation ).
Main results：NE significantly increased mean arterial pressure, systolic arterial pressure and diastolic arterial pressure immediately, but increased partial pressure of arterial carbon dioxide and failed to improve oxyhemoglobin saturation. Urine output markedly improved in all groups but more significantly in DP and NE. DOB significantly improved more heart rate, myocardial contractility and partial pressure of arterial oxygen than other groups. DP increased central venous pressure immediately. Decreased body temperature was noted in all groups during shock, resuscitation and after resuscitation. At 30 minutes after resuscitation, all results of hemodynamic measurement became worse.
Conclusions：We suggest using NE to restore blood pressure in dogs with severe hypotension but not in low oxyhemoglobin saturation. DOB can be used to stable and improve heart function. DP can increase central venous pressure significantly. While acute renal failure or low urine output occurred in HS, DP or NE along with aggressive fluid resuscitation can improve renal perfusion. Intensive monitoring and warm crystalloidal fluid are recommend. To achieve the best resuscitative effect, this study advocates the use of both aggressive crystalloid infusion and sympathomimetic drugs therapy adjusted by intensive hemodynamic monitoring for resuscitation of HS dogs.
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