Der Anaesthesist
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Randomized Controlled Trial Comparative Study Clinical Trial Controlled Clinical Trial
[Prevention of myocardial ischemia. Study following aortocoronary bypass operation with the calcium antagonist diltiazem].
The incidence of postoperative myocardial infarction (MI) is proportional to the incidence of myocardial ischaemic episodes. Therefore, the prevention of such episodes is of great clinical importance. METHODS. ⋯ DIL results in marked haemodynamic stabilisation during CABG, especially in the period immediately after extra-corporeal circulation. This might serve as an explanation for the significant reduction in ischaemic episodes in the DIL group compared to the other two groups. Therefore, perioperative prevention of myocardial ischaemia with the calcium antagonist DIL seems to be favourable in patients during CABG.
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On the subject of natriuretic peptides there is a great deal of controversy, and intensive research efforts have been made studying their effects on electrolyte homeostasis. In the early 1980s, a peptide that caused diuresis, natriuresis, and had a relaxant effect on vascular smooth muscle was discovered independently by several groups. This was the breakthrough for the identification of natriuretic peptides, followed by the characterisation of the amino-acid sequences of several species. ⋯ These results were encouraging for the use of URO in clinical trials as a tool to prevent acute renal failure (ARF) in patients following heart transplantation and for treatment of incipient ARF in patients following liver transplantation. Summarising the results of these two studies, URO represents a new approach for not only prevention, but also for treatment of ARF following organ transplantation. This opens up new possibilities for the treatment of ARF of other origins in intensive care medicine.
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Clinical Trial
[Estimation of acute left ventricular afterload alterations. Transesophageal echocardiography in artificially respirated patients].
Left ventricular afterload is most accurately represented by left ventricular end-systolic wall stress, but in clinical practice is commonly estimated by the systemic vascular resistance (SVR). End-systolic wall stress can be derived from M-mode and two-dimensional (2D) echocardiograms in combination with systolic arterial pressure (SAP). We tested transoesophageal echocardiography for the assessment of acute left ventricular afterload alterations in ventilated patients requiring cardiovascular support with noradrenaline or nitroglycerine. METHOD. With approval from the local ethics committee, we studied afterload alterations in 11 hypotensive patients who were treated by increasing the dosage of i.v. noradrenaline by 2-5 micrograms/min in order to raise mean arterial pressure (MAP) by 20 mmHg. In another 10 patients with MAP over 95 mmHg, nitroglycerine was raised from 2 to 4 mg/h, aiming at a 20 mmHg MAP reduction. MAP and SAP were monitored via a radial artery cannula, cardiac output (CO) was measured with the thermodilution technique using a Swan-Ganz catheter, and SVR was calculated from CO, MAP, and right atrial pressure. M-mode and 2D echocardiograms were obtained from the cross-sectional short-axis view of the left ventricle and recorded shortly before and during treatment when MAP had changed by 20 mmHg. Left ventricular total area (TA) and cavity area (A) including the papillary muscles were obtained from end-systolic 2D echocardiograms, while end-systolic internal diameter (ID) and posterior wall thickness (HW) were measured in the M-mode. Wall stress was calculated in the M-mode as: WSM = 0.33 x SAP x ID/(HW x (1+HW/ID)), and in the 2D mode as: WS2D = 1.33 x SAP x A/(TA-A). ⋯ paired t-test (P < 0.05), regression analysis. RESULTS. Afterload alterations were reflected by significant changes of WS2D (-41%, +68%), WSM (-26%, +38%), and SVR (-15%, +50%). WSM and SVR underestimated changes of WS2D by 15%-30%. WSM changes due to SAP rather than to left-ventricular dimensional changes. No correlation was found between WS2D or WSM and SVR. Inter-observer variability for echocardiographic wall stress was reasonable (WS2D 4%, WSM 10%). CONCLUSIONS. Acute changes of left ventricular afterload and dimensions were clearly indicated by 2D measurements. As M-mode measures were not conclusive for left ventricular dimensional changes, WSM was not an appropriate parameter for acute afterload alterations. WS2D is an afterload index superior to WSM that cannot be estimated by SVR.
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Clinical Trial
[Accidental hypothermia in trauma patients. Is it relevant to preclinical emergency treatment?].
Trauma patients are at great risk of accidental hypothermia (body temperature [BT] < 36 degrees C). Hypothermia influences the functioning of all organ systems and can lead to pathological changes, which in turn additionally complicate the trauma. Furthermore, hypothermia can, e.g., by influencing blood coagulation (reduction of thrombocyte aggregation, increased fibrinolysis) have a markedly unfavourable impact upon the in-hospital surgical treatment of the trauma patient. ⋯ Based upon our findings, accidental hypothermia poses a relevant problem in the prehospital treatment of trauma patients. It is not limited to a special season of the year. The variability or total absence of definite diagnostic symptoms underlines the necessity for prehospital BT monitoring, whereby tympanic-membrane thermometry has proven to be a worthwhile method.
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A 31-year-old pregnant woman had to undergo emergency abdominal surgery due to acute intestinal obstruction. The patient's preoperative history demonstrated multiple allergies as well as abdominal trauma several years before. The physical examination--including sonography of the two fetuses--showed no pathological signs. Anaesthesia was induced intravenously with the operating table tilted to the left side, using routine precautions pre-oxygenation, and rapid sequence intubation, and was maintained unproblematically. About 20 min after the onset of surgery, hypotension, tachycardia, and a drop in oxygen saturation appeared. Volume substitution and the application of vasoactive drugs failed to stabilise the haemodynamic situation. Elevation of the pregnant uterus and increased left tilzing of the operating table did not lead to improvement. The development of eyelid edema led to the diagnosis of an anaphylactic reaction. The patient was treated successfully with epinephrine, antihistamines, and corticosteroids (prednisolone). The suspicion of latex-related allergy was verified postoperatively by radio-allergen-sorbent test (RAST) and prick and scratch tests. ⋯ Due to the obviously increasing number of latex-related allergies, especially in atopic persons and patients with frequent latex exposure, the patient's exact history is highly significant [4, 7, 18-20]. This includes--because of suspected cross-reactions--questions concerning allergic reactions to bananas and chestnuts [1, 16, 24]. If a latex-related allergy is suspected, all latex- or rubber-containing materials have to be consequently avoided. Because of the suspected allergies by inhalation via rubber-containing masks or tracheal tubes, these devices also have to be avoided and replaced, possibly by silicone materials [1, 4, 5, 16]. Premedication with H1- and H2-antagonists (dimetindene and cimetidine) and glucocorticoids (administered 12h before surgery and given twice) is indicated [5, 19, 12, 21]. In cases of latex allergy, the above-mentioned basic therapeutic measures have to be undertaken even in pregnancy, including immediate replacement of all latex-containing materials. The diagnosis of latex allergy should be verified by cutaneous testing [4, 18, 24].