Prevention of perioperative venous thromboembolism and coronary events: differential responsiveness to an intervention program to improve guidelines adherence

INTRODUCTION

Prevention of venous thromboembolism and coronary events (with beta-blockers) during and after surgery is at the top of a list of safety practices for hospitalized patients, recommended by the Agency for Health Care Research and Quality (AHRQ). We wished to determine and improve adherence to clinical guidelines for these topics in our institution. PATIENTS, MATERIAL, AND METHODS: A prospective survey was conducted over several weeks on operated patients in a 1200-beds medical center (a teaching, community and referral hospital in Jerusalem, Israel). Eligibility for and actual administration of prophylactic treatment with anticoagulant and beta-blockers were determined. Following an intervention program, which included staff meetings, development of local protocols, and academic detailing by a nurse, the survey was repeated.

RESULTS

In general, adherence to recommended anticoagulation prophylaxis was low, found in only 29% [95% confidence interval (CI) = 23-36] of eligible patients. After the intervention, adequate anticoagulation increased to 50% (95% CI = 40-59) of eligible patients (P < 0.001). Initiation of beta-blockers in preventing perioperative cardiac events was very low (0%, 95% CI = 0-5%) and did not increase after intervention.

CONCLUSIONS

Adherence to guidelines for prevention of surgical complications was found to be low in our institution. A multifaceted intervention significantly increased use of prophylaxis for venous thromboembolism but not for coronary events. This differential response suggests that the success of a quality improvement project strongly depends on topic content and its phase of acceptance.

Isoflurane does not mimic ischaemic preconditioning in decreasing hydroxyl radical production in the rabbit

BACKGROUND

Reactive oxygen species are an important mediator in isoflurane-induced myocardial preconditioning. However, hydroxyl radicals are also released during reperfusion after regional ischaemia. The purpose of the present study was to test whether ischaemic preconditioning and isoflurane would influence the production of hydroxyl radicals during reperfusion.

METHODS

After i.v. administration of salicylate 100 mg kg(-1) and a 30 min stabilization period, New Zealand White rabbits were subjected to 40 min of regional myocardial ischaemia and 2 h of reperfusion. Ischaemic preconditioning was elicited by 5 min ischaemia followed by 10 min reperfusion (before the 40 min ischaemia). In another group, isoflurane (2.1%) was administered for 30 min, followed by 15 min washout, before the long ischaemia. Area at risk and infarct size were assessed by blue dye injection and tetrazolium chloride staining. We quantified the level of OH-mediated conversion of salicylate to its dihydrobenzoate derivatives (2,3- and 2,5-DHBAs). Normalized values of the DHBAs (ng DHBA per mg salicylate) were calculated.

RESULTS

Mean (se) infarct size was 57 (6)% of the risk area in the untreated controls. This was significantly smaller in the ischaemic preconditioning and isoflurane groups: 22 (5) and 23 (6)% respectively. At 10 min of reperfusion, ischaemic preconditioning limited the mean increase in 2,3-DHBA to 24% from baseline, compared with 81% in control and 74% in the isoflurane group. Normalized 2,5-DHBA was maximally increased by 75% in the untreated group, 4 min after reperfusion. Ischaemic preconditioning significantly inhibited this increase (24% increase from baseline, P<0.01). However, the increase observed in the isoflurane group was not different from control (71%).

CONCLUSIONS

As already known, ischaemic preconditioning and isoflurane markedly reduced infarct size. However, only ischaemic preconditioning decreased postischaemic production of hydroxyl radicals. These different effects suggest different protective mechanisms at the cellular level.

Ischaemic preconditioning but not isoflurane prevents post-ischaemic production of hydroxyl radicals in a canine model of ischaemia-reperfusion

BACKGROUND AND OBJECTIVE

Isoflurane has been shown to mimic ischaemic preconditioning (IPC). The protective effect of IPC, or applying isoflurane or perfusion with the 'push-pull' complex zinc-desferrioxamine (Zn-DFO) in the canine heart, was investigated.

METHODS

Thirty minutes after salicylate administration (100 mg kg(-1)) the heart was exposed. All dogs were subjected to a 10 min left anterior descending artery occlusion followed by 2 h of reperfusion. In Group I (n = 9) isoflurane (2.5%) was administered 10 min prior to and during ischaemia. In Group II (n = 8), IPC was elicited by 5 min coronary artery occlusion, followed by 5 min of reperfusion, prior to the 10 min ischaemia. In Group III (n = 9) Zn-DFO (2.5 mg kg(-1)) was given 10 min prior to ischaemia. The effects of these interventions were compared to control (n = 10). Coronary sinus blood concentrations of salicylate, 2,3-dihydroxybenzoic acid (DHBA), lactate, pH and oxygen content were monitored.

RESULTS

In the control group, 2,3-DHBA increased by 32% above the pre-ischaemic value (P < 0.05). In contrast, in the IPC hearts, a significant decrease in the production of 2,3-DHBA was observed (40% lower than baseline, P < 0.01). In the isoflurane group only a 13% (and non-significant) decrease was noticed. In the Zn-DFO group a 33% decrease was found (P < 0.01). The increase in lactate concentrations in the IPC and Zn-DFO groups was significantly smaller than that of control and isoflurane groups.

CONCLUSIONS

IPC protected the heart against the deleterious effects of reperfusion, possibly by amelioration of the level of oxygen-derived reactive species, and the complete inhibition of reactive hydroxyl radical production. Isoflurane did not prove to be as effective in reducing the free radical damage.

Myocardial infarction after vascular surgery: the role of prolonged stress-induced, ST depression-type ischemia

OBJECTIVES

The goal of this study was to investigate the nature of the association between silent ischemia and postoperative myocardial infarction (PMI).

BACKGROUND

Silent ischemia predicts cardiac morbidity and mortality in both ambulatory and postoperative patients. Whether silent stress-induced ischemia is merely a marker of extensive coronary artery disease or has a closer association with infarction has not been determined.

METHODS

In 185 consecutive patients undergoing vascular surgery, we correlated ischemia duration, as detected on a continuous 12-lead ST-trend monitoring during the period 48 h to 72 h after surgery, with cardiac troponin-I (cTn-I) measured in the first three postoperative days and with postoperative cardiac outcome. Postoperative myocardial infarction was defined as cTn-I >3.1 ng/ml accompanied by either typical symptoms or new ischemic electrocardiogram (ECG) findings.

RESULTS

During 11,132 patient-hours of monitoring, 38 patients (20.5%) had 66 transient ischemic events, all but one denoted by ST-segment depression. Twelve patients (6.5%) sustained PMI; one of those patients died. All infarctions were non-Q-wave and were detected by a rise in cTn-I during or immediately after prolonged, ST depression-type ischemia. The average duration ofischemia in patients with PMI was 226+/-164 min (range: 29 to 625), compared with 38+/-26 min (p = 0.0000) in 26 patients with ischemia but not infarction. Peak cTn-I strongly correlated with the longest, as well as cumulative, ischemia duration (r = 0.83 and r = 0.78, respectively). Ischemic ECG changes were completely reversible in all but one patient who had persistent new T wave inversion. All ischemic events culminating in PMI were preceded by an increase in heart rate (delta heart rate = 32+/-15 beats/min), and most (67%) of them began at the end of surgery and emergence from anesthesia.

CONCLUSIONS

Prolonged, ST depression-type ischemia progresses to MI and is strongly associated with the majority of cardiac complications after vascular surgery.

Perioperative myocardial ischemia in cataract surgery patients: general versus local anesthesia

Patients having cataract surgery are usually elderly and have risk factors for ischemic heart disease. We sought to determine the incidence of perioperative myocardial ischemia in patients having cataract surgery and compare the influence of local anesthesia (LA) and general anesthesia (GA). Eighty-one patients undergoing cataract surgery with at least two risk factors for ischemic heart disease were monitored continuously for 24 h by using electrocardiogram leads II and V5 and a Holter recorder (Medilog 4500, Oxford Ltd, UK). Patients were randomly allocated to two groups, either LA (n = 39) or GA (n = 42). In the LA group, a peribulbar block was performed, whereas a similar block was performed in the GA group after tracheal intubation. The study demonstrated that cataract patients suffered from a frequent incidence of perioperative myocardial ischemia (31%). There was no difference in the incidence rate between the groups: 12 of 39 in the LA group and 13 of 42 in the GA group (P: = NS). However, the number of ischemic episodes was significantly increased in the GA group (18 vs. 13 in the LA group) (P<0.05), and there were significantly more intraoperatively in the GA group (8 vs. 1) (P<0.01). All intraoperative ischemic events were associated with tachycardia (> or =20% of baseline), whereas postoperative ischemic changes were mostly independent of heart rate. Only one of the ischemic patients (in the GA group) was admitted as a result of intractable chest pain. There were significantly less intraoperative episodes in the LA group, suggesting that LA may be safer than GA in patients during this type of surgery.

Anaesthetic management of a patient undergoing reoperation for pathway obstruction after fontan operation

Since 1968, the Fontan operation, or its various modifications, have provided a functional correction in an increasingly complex spectrum of congenital heart malformations.1.2 These procedures have gained wide acceptance because of very good intermediate and longterm results2. However, as survival increases, follow up of these patients has shown more prevalent reoperations for obstruction of the surgically created corrective pathway.3 perioperative management of these patients requires an understanding of the unique anatomic and physiologic changes occurring in this condition. In this report, we review our anaesthetic management of a patient who underwent reoperation for thrombotic occlusion of the conduit from a previous Fontan procedure.

Halothane modifies oxygen free radical activity on the voltage-sensitive calcium channels in canine myocardial membranes

BACKGROUND

The functional derangements in the myocyte cell membrane, the sarcolemma, during short myocardial ischaemia and reperfusion are attributed to excessive influx of Ca2+ ions via the voltage-sensitive calcium channels (VSCC) and to the free radical-related injury. However, it is unclear whether the primary changes in the VSCC should be attributed to the ischaemic effect or to free radical action on channel constituents. Under these circumstances of ischaemia and reperfusion, volatile anaesthetics have exhibited protective properties on the myocardium. The present study is aimed at characterizing the effect of artificially-generated oxygen free radicals on the VSCC in canine sarcolemma, independently of the effect of ischaemia, and the effect of halothane on the membranes during the surge of the free radicals.

METHODS

Selective production of free radicals (O2-, CO2-) was made by gamma irradiation of isolated sarcolemma membranes with 137 Cesium (Cs), in the presence of 20 mM sodium formate. Control studies were performed without formate in the aqueous solution. In an additional group, liquid halothane (3 microl. 1.9 vol%) was added to the sarcolemma / formate preparation immediately prior to irradiation. The effects of free radicals on the VSCC was evaluated by redioligand binding studies of the calcium channel blocker [3H] isradipine to the sarcolemma.

RESULTS

In six control studies, the rediolytic aqueous species produced by 137 Cs irradiation resulted in unchanged [3 H] isradipine binding. In the presence of formate [n=9], the free radicals have caused a 23% to 25% decrease, both, in density and dissociation constant (P=0.05) of [3 H]isradipine to the VSCC binding sites. When superoxide radicals were generated in the presence of 1.9% halothane and formate (n=6), a significant increase in maximal binding capacity (by 55% +/- 2; P<0.01) and in the dissociation constant (by 209% +/- 35, P<0.01) occurred.

CONCLUSION

Oxidative free radicals which are generated by gamma irradiation exerted minimal changes on the normal function of the VSCC as reflected by the non-significant changes in [3 H] isradipine specific binding. Introduction of halothane into free radical generating system causes acute perturbations to the VSCC kinetics, and does not provide protection to the cardiac membranes.

Coronary spasm during outpatient fiberoptic laser bronchoscopy

A 63-year-old woman with metastatic breast cancer was referred to our bronchoscopy unit for outpatient laser resection of an endobronchial mass through fiberoptic bronchoscopy. The patient had no history of ischemic heart disease. During the procedure, the patient developed an ST-segment elevation and a complete atrioventricular block. IV nitroglycerin and morphine were effective in treating this episode. In this patient, we were able to demonstrate a focal spasm by postbronchoscopy coronary angiography.

Coronary Artery Bypass Grafting without Cardiopulmonary Bypass: Improvement in Cardiac Function Following Enflurane Anaesthesia during Coronary Occlusion

Severe adverse effects, especially neurologic complications after cardiopulmonary bypass have lead to the development of techniques for performing coronary artery bypass graft surgery without cardiopulmonary bypass. Laboratory and clinical studies confirmed the positive role of enflurane anaesthesia in preventing myocardial dysfunction following an ischaemic interval. The aim of this study was to evaluate the haemodynamic response to enflurane anaesthesia during single graft coronary bypass surgery without cardiopulmonary bypass. Twenty one patients were divided randomly into two groups: control and enflurane groups. Haemodynamic parameters and those derived from a pulmonary artery catheter were recorded and analysed. In the enflurane group, the amount of fentanyl administered was considerably less than in the control group: 25.7 +/- 3.8 microg/kg vs 36.8 +/- 1.6; p=0.03. The mean arterial pressure during enflurane administration was lower than in control group, but the difference was not significant. Despite a dearease in left ventricular function during the performance of the anastomosis in the enflurane group, a significant recovery was noted after 20 minutes of reperfusion: cardiac index increased from 1.4 +/- 0.1 to 1.85 +/- 0.1 L/min/m2 and left ventricular stroke work index from 15.8 +/- 1.1 to 27.7 +/- 6.7 g.m.m2 . In the control group, the deterioration in cardiac function observed during the graft anastomosis did not recover till the end of the surgical procedure. We conclude that enflurane anaesthesia may be a positive addition to fentanyl-based anaesthesia by improving myocardial function following CABG without bypass surgery.

ST segment changes following retinal surgery

STUDY OBJECTIVE

To describe the perioperative cardiac morbidity in adult patients undergoing retinal surgery using continuous Holter monitoring.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

56 patients scheduled for elective retinal surgery with local anesthesia.

INTERVENTIONS

Patients were monitored continuously for 24 hours using a Holter recorder. Blood samples for creatine phosphokinase (CPK) and serum myocardial creatine phosphokinase (CPK-MB) were taken preoperatively and 24 hours postoperatively. The characteristics of myocardial ischemia were compared according to the number of risk factors for ischemic heart disease.

MEASUREMENTS AND MAIN RESULTS

The overall incidence of perioperative myocardial ischemia was high: 26.7% (n = 15). These patients exhibited 41 episodes of ischemia with mean ST segment change from baseline of 2.2+/-0.7 mm. However, almost all (93.3%) ischemic episodes were silent. Patients with two risk factors or more had 77% more episodes of ischemia than patients with one risk factor (p < 0.005), and the duration of ischemia was 47+/-22.5 minutes compared with 34.8+/-27.5 minutes (p = NS). The first episode of ischemia occurred an average of 10 hours after surgery. No patient had intraoperative evidence of ischemia. Half of the ischemic episodes were associated with an increase in heart rate. No patient had evidence of acute myocardial infarction.

CONCLUSION

Retinal surgery with local anesthesia is accompanied by a high incidence of postoperative myocardial ischemia. No negative outcome was correlated to the occurrence of postoperative myocardial ischemia. The significance of these findings has yet to be evaluated.

Systolic pressure variation predicts the response to acute blood loss

STUDY OBJECTIVE

To evaluate systolic pressure variation (SPV), defined as the difference between the maximum and minimum systolic blood pressure measured during a controlled mechanical respiratory cycle, as a predictor of the cardiac output (CO) response to an acute decrease in ventricular preload.

DESIGN

Prospective study with each subject serving as his or her own control.

SETTING

Cardiac surgery operating rooms of a university medical center.

PATIENTS

15 adults with good ventricular function undergoing coronary artery bypass grafting.

INTERVENTION

During stable anesthetic conditions and before surgical stimulation, 500 ml of blood was removed from each patient over 10 minutes.

MEASUREMENTS AND MAIN RESULTS

CO, central venous pressure (CVP), pulmonary artery diastolic pressure, and pulmonary artery occlusion pressure (PAOP), and SPV before and after phlebotomy were recorded. Phlebotomy was associated with significant decreases in CVP, PAOP, and CO, and an increase in SPV. Of these variables, SPV was the best predictor of the percent decrease in CO resulting from blood loss.

CONCLUSION

SPV is a dynamic measurement, which, by revealing the response to small cyclical changes in left ventricular preload that occur during the controlled mechanical respiratory cycle, is a better predictor than central filling pressures of the response of CO to acute decreases in preload that occur as a result of acute blood loss.

Myocardial ischemia in sedated patients undergoing fiberoptic bronchoscopy

STUDY OBJECTIVE

To study the incidence of myocardial ischemia and related hemodynamic alterations in sedated patients undergoing fiberoptic bronchoscopy (FOB).

DESIGN

Prospective study.

SETTING

Tertiary care, university hospital.

PATIENTS

Twenty-nine patients, age 50 years or older, undergoing elective FOB.

INTERVENTIONS

Myocardial ischemia was assessed by continuous ECG monitoring beginning 30 min before, and until 2 h after FOB.

MEASUREMENTS AND RESULTS

During FOB, there was a significant rise in heart rate (89+/-3 [mean+/-SE] to 120+/-4 beats/min) and fall in oxygen saturation (95+/-1 to 90+/-1%). There was no significant rise in systolic or diastolic BP. Five patients (17%) had myocardial ischemia during FOB that lasted 20+/-8 min. Their demographic and pre-FOB characteristics were not different from the other patients. Compared to baseline values, a significant rise in heart rate, a fall in oxygen saturation, and no significant change in BP were observed during FOB in patients, both with or without ischemia. Although not statistically significant, ischemia was associated with more protracted procedures.

CONCLUSIONS

Myocardial ischemia may develop in elderly patients undergoing FOB. This observation encourages the routine use of ECG and oximetry during FOB, allowing for early intervention to prevent the dangerous combination of hypoxia, tachycardia, and myocardial ischemia. Moreover, this study suggests that methods to ensure oxygenation during FOB should be adhered to, and that the routine administration of atropine should be reconsidered.

Cerebral protection using retrograde cerebral perfusion during hypothermic circulatory arrest

BACKGROUND

Retrograde cerebral perfusion through the superior vena cava (SVC) has been proposed to protect the brain from ischaemic injury during profound hypothermic circulatory arrest (PHCA). Its contribution to cerebral protection is unclear. Furthermore, the addition of anaesthetic or vasodilating agents to the SVC perfusate to enhance brain protection, has never been described.

METHODS

In three patients undergoing repair of the ascending aorta utilizing PHCA, the upper body was retrogradely perfused with cold (16 degrees C) blood through the SVC by the cardiopulmonary bypass pump. Electroencephalographic activity was monitored using a computerized electroencephalographic monitor (Cerebro Trac 2500, SRD). Perfusion pressure was measured at a port in the cannula connector. Etomidate or thiopentone was injected into the SVC perfusate to arrest reappearing electroencephalographic activity. Nitroglycerin or nitroprusside was injected into the perfusate to increase retrograde flow and maintain a constant perfusion pressure.

RESULTS

During PHCA periods of up to 61 min, recurrent electroencephalographic activity was abolished by the retrograde administration of small boluses of etomidate (total 50 mg) or thiopentone (total 500 mg). Nitroprusside (100 micrograms) and nitroglycerin (2 micrograms.kg-1.min-1) increased retrograde flow from 220 to 550 and 660 ml.min-1, respectively, while maintaining perfusion pressure (25-26 mmHg). Recovery from anaesthesia and surgery was uneventful, with no adverse neurological sequelae.

CONCLUSION

Injection of anaesthetic agents into the retrograde SVC perfusate during PHCA, can suppress reoccurring electroencephalographic activity and retrograde injection of vasodilators can facilitate an increase in perfusion. It is suggested that both may augment brain protection.

Danaparoid for cardiopulmonary bypass in patients with previous heparin-induced thrombocytopenia

Anticoagulation for cardiopulmonary bypass in patients with heparin-induced thrombocytopenia requires the use of other anticoagulants. We report a case in whom this was achieved using the heparinoid danaparoid (Orgaran). Based on our experience and a review of the literature, we provide guidelines for managing these rare patients. A danaparoid dose substantially lower than that recommended by the manufacturer may minimize bleeding complications.

Halothane prevents postischemic production of hydroxyl radicals in the canine heart

BACKGROUND

Recent studies indicate that during regional myocardial ischemia and subsequent reperfusion, volatile anesthetics may provide protection against free radical-related injury. The effect of halothane on free radical production during ischemia and reperfusion, in the canine heart, was investigated. The level of hydroxyl radical (.OH)-mediated conversion of salicylate to its dehydroxybenzoate derivatives (2,3-DHBA and 2,5-DHBA) was monitored.

METHODS

Under general anesthesia, the heart was exposed through median sternotomy. Salicylate (100 mg/kg given intravenously) was administered 30 min before left anterior descending artery occlusion. Six dogs were studied using inhaled halothane (1.6%) 10 min before and during the 10-min ischemic period, followed by 50 min of reperfusion, and then they were compared with seven other dogs used as controls. Blood concentrations of salicylate, 2,3-DHBA and 2,5-DHBA, K+, lactate, oxygen content, and pH were monitored.

RESULTS

An acute increase in the normalized concentrations of 2,3-DHBA and 2,5-DHBA was observed in the control animals during reperfusion. In contrast, halothane inhalation completely inhibited the production of both metabolites (P < 0.02), but 2,5-DHBA concentrations in the halothane-treated group were even less than the basal level (P < 0.05). The increase in lactate concentrations in the experimental animals was significantly less than that of controls (P < 0.05) and followed the same time-dependent pattern as the changes in K+ and pH. Halothane significantly decreased (P < 0.0001) the difference in oxygen content between coronary sinus and aortic root blood, suggesting decreased oxygen utilization during reperfusion.

CONCLUSIONS

Halothane completely inhibited the production of .OH, and its administration may protect the heart from the deleterious effect of oxygen-derived reactive species, with attenuation of the metabolic response to ischemia.

Changes in cerebrospinal fluid pressure and lactate concentrations during thoracoabdominal aortic aneurysm surgery

BACKGROUND

Although ischemic injury to the spinal cord is a well-known complication of aortic surgery, no metabolic markers have been identified as predictors of an adverse outcome. This study evaluated the effect of cerebrospinal fluid (CSF) drainage, with and without distal femoral perfusion or moderate hypothermia on blood and CSF lactate concentrations and CSF pressure during thoracoabdominal aortic aneurysm surgery.

METHODS

Three nonconcurrent groups of patients were studied prospectively: patients with normal body temperature (35 degrees C) but without distal femoral bypass (n = 6), patients with normal body temperature with bypass (n = 7), and patients with hypothermia (30 degrees C) and bypass (n = 8). In all patients, CSF pressure was recorded before, during, and after aortic cross-clamping. During the surgical repair, CSF drainage was performed using a 4-Fr intrathecal silicone catheter. Blood and CSF lactate concentrations were measured throughout the operation.

RESULTS

Significant increases in blood (490%) and CSF (173%) lactate concentrations were observed during and after thoracic aortic occlusion in patients with normothermia and no bypass (P < 0.02 and 0.05, respectively). Distal perfusion attenuated the increase in both blood and CSF lactate (P < 0.01), and a further reduction was achieved with hypothermia of 30 degrees C (P < 0.001). Patients who became paraplegic showed a greater increase in CSF lactate concentrations after aortic clamp release compared with those who suffered no neurological damage (275% vs. 123% of baseline; P < 0.05). Increased CSF pressure of 42-60% (P < 0.005) was noted soon after thoracic aortic occlusion, both with and without distal femoral bypass.

CONCLUSIONS

Incremental reductions in CSF lactate concentrations were achieved using distal femoral bypass and hypothermia. The reduction in CSF lactate correlated with the methods used to protect the spinal cord during thoracoabdominal aortic aneurysm surgery and was associated with better outcome. Decompression by distal bypass of the hemodynamic overload caused by aortic occlusion was insufficient to eliminate the acute increase in CSF pressure. Cerebrospinal fluid lactate measurements during high aortic surgery may accurately represent the spinal cord metabolic balance.

Analysis of lysophophatidylcholine-induced endothelial dysfunction

Endothelial dysfunction caused by the early atherosclerotic process or by endothelial exposure to atherogenic lipids, including lysophosphatidylcholine (lysoPC), is characterized by a selective impairment of responses mediated by the pertussis toxin-sensitive Gi-2 protein. Experiments were performed to analyze the mechanisms underlying this effect. Bradykinin (BK: Gi-2 protein-independent), serotonin (5-HT: Gi-2 protein-dependent), or direct activation of the G(i-2)-protein by mastoparan increased the release of endothelium-derived nitric oxide (EDNO) from porcine arterial endothelial cells (EC). LysoPC decreased the release of EDNO caused by 5-HT, but did not affect the response to BK or mastoparan. LysoPC did not increase production of superoxide radicals detected by lucigenin-enhanced chemiluminescence. Western blot analysis showed no difference in the level of immunoreactive Gi alpha-2 between control and lysoPC-treated cells. Activation of the Gi-2 protein by serotonergic or alpha 2-adrenoceptor stimulation decreased the pertussis toxin-catalyzed ADP-ribosylation of Gi alpha-2 protein in membranes from control but not lysoPC-treated cells. However, direct activation of the Gi-2 protein by mastoparan inhibited the ADP-ribosylation in membranes from control and lysoPC-treated cells. The toxin-catalyzed reaction was reduced in lysoPC-treated cells or lysoPC-treated membranes. LysoPC reduced the ability of endothelin to increase GTP gamma S binding to the Gi-2 protein but did not affect the activity of mastoparan. These results suggest that lysoPC inhibits a pertussis toxin-sensitive signaling pathway in EC by an effect consistent with receptor:Gi-2-protein uncoupling.

Normothermic continuous blood cardioplegia improves electrophysiologic recovery after open heart surgery

BACKGROUND

Myocardial protection during open heart surgery is based on administration of oxygenated blood cardioplegia, the preferred temperature of which is still under debate. The current randomized study was designed to prospectively evaluate the quality of myocardial protection and the functional recovery of the heart with either normothermic (group N) or hypothermic (group H) oxygenated blood cardioplegia.

METHODS

Under continuous electrocardiographic Holter monitoring, 42 patients were randomly scheduled to receive either normothermic (33.5 degrees C) or hypothermic (10 degrees C) cardioplegia solutions during coronary bypass grafting surgery. Blood samples for creatinine phosphokinase, creatinine phosphokinase-MB, lactate, epinephrine, and norepinephrine were withdrawn during cardiopulmonary bypass via a coronary sinus cannula.

RESULTS

Active cooling in group H on initiation of cardiopulmonary bypass was characterized by transition through ventricular fibrillation in 75% of patients, whereas in group N atrial fibrillation occurred in 65% of patients. On myocardial reperfusion, sinus rhythm spontaneously resumed in 95% of group N patients compared to 25% in group H (P = 0.0003). In the latter, 75% of patients developed ventricular fibrillation often followed by complete atrioventricular block, which necessitated temporary pacing for a mean duration of 168 +/- 32 min. Both groups showed a similar incidence of intraventricular block and ST segment changes. However, the incidence of ventricular premature beats in the first 16 h after cardiopulmonary bypass was significantly greater in group H (P < 0.05), 20 +/- 26/h, compared to 3 +/- 5/h in group N. Blood concentrations of lactate, creatinine phosphokinase, epinephrine, and norepinephrine increased gradually during the operation, but the differences between the groups were not significant.

CONCLUSIONS

The current prospective human study suggests that the increased susceptibility for ventricular fibrillation and dysrhythmia, and the delayed recovery of the conduction system after hypothermic myocardial protection, are related to temperature-induced changes in vital cellular functions of the conduction tissue in the postischemic period. Both cardioplegic methods provide adequate myocardial protection but normothermic oxygenated blood cardioplegia may accelerate recovery of the heart after cardiopulmonary bypass.

Luke warm blood cardioplegia for CAB surgery in patients with severely impaired LV function. Improved results

Ward blood cardioplegia (WBC) has recently been reported to improve myocardial protection in adult open heart surgery, especially in high risk cases. However, WBC has been reported to have some disadvantages including narrow safety margins concerning brain and kidney perfusion. We therefore modified our technique to utilize luke-warm blood cardioplegia (LWBC). We carried out 470 open heart procedures using luke-warm cardioplegia (anterograde + retrograde perfusion) from 1/2/1991 - 30/9/1992; 94 had LVEF < 30% and form the basis of this study. Other major risk factors in this group included: > 70 yrs - 26 patients, L main > 50% - 14 patients, emergencies - 11 patients, redo's - 3 patients. Eightyone patients underwent CAB only; 3 had additional MVR, 3 additional closure acute VSD of whom one underwent additional LV aneurysmectomy, one additional AVR; 4 patients underwent AVR only, and 2 MVR. Average number of grafts/patient for the 81 isolated CAB's was 4.5. IABP was necessary postbypass in 4 patients (9 emergencies were on IABP support at time of operation). Thirty day mortality was 3 patients (3.2%). Late mortality was 5 cases. These results are superior to those achieved using cold protection and warm blood cardioplegia. LWBC is a safe method for myocardial protection in patients undergoing CAB, particularly when LV function is severely compromised.

Patient data management systems in anaesthesia: an emerging technology

The purpose of this review is to define the expectations of an on-line automatic patient data management system (PDMS) into anaesthesia work-stations in and around the operating room suite. These expectations are based on review of available information in the medical literature, and trials of several systems that are available commercially, three of them in a more detailed fashion (i.e. Informatics, Datex and North American Drager). The ideal PDMS should: -- communicate with and capture the information from different monitors, anaesthesia machines and electronic gadgets (e.g., infusion pumps) used in the operating room (OR), while presenting selected relevant values and trends on a screen. -- inform the anaesthetist of deviations from preselected limits of physiological and technical values. In the future, the system will hopefully be upgraded to include an algorithm-based decision support system. -- communicate with the hospital mainframe computer, and automatically transfer demographic data, laboratory and imaging results, and records obtained during preoperative consultations. -- at the end of each anaesthetic procedure, create an anaesthetic record with relevant data automatically collected by the system, as well as that which was entered manually by the physician during the procedure. A copy of this anaesthesia file must be kept on a computerized archive system. None of the systems so far evaluated fulfilled all our expectations. We have therefore adopted approach for the gradual introduction of such a system into our OR environment over the next two to five years, during which expected improvements may be incorporated to upgrade the system.

Echocardiographic evaluation of the coronary sinus

The purpose of this study was to compare transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of the coronary sinus and its blood flow. Forty patients were studied by TTE and TEE. The distal coronary sinus and its right atrial communication could be identified in 21 of 40 by TTE, and in all patients by TEE. Coronary sinus diameter measurement at the right atrial communication was possible by TTE in 16 of 40, and in all patients by TEE (maximal diameter 6 to 14 mm, mean 9 +/- 2). Flow velocity measurement by pulsed Doppler was possible in 25 of 40 patients (63%) by TEE, and in none by TTE. The flow velocity pattern was similar to central vein flow velocity, with systolic and diastolic antegrade waves, and a small retrograde end diastolic wave. The coronary sinus cross-sectional area was measured in 5 patients by intravascular ultrasound. It varied in size and shape during the cardiac cycle, reaching a maximum (0.3 to 1.5 cm2) at end diastole, and decreasing by 40% to 70% at end systole. TEE is superior to TTE in the evaluation of the coronary sinus and its blood flow velocity. However, because of the variability in cross-sectional area size and shape, measurement of coronary sinus blood flow may be inaccurate.

Halothane modifies ischemia-associated injury to the voltage-sensitive calcium channels in canine heart sarcolemma

BACKGROUND

Recent experimental data suggest that functional and metabolic changes in the myocardium caused during ischemia and subsequent reperfusion may be attenuated by the volatile anesthetics through the prevention of intracellular calcium accumulation. The main purpose of the current research is to identify a mechanism responsible for the alterations of ischemia-associated injury to the voltage-sensitive Ca2+ channels (VSCC) in the sarcolemma during halothane anesthesia.

METHODS

The effect of 10 min myocardial ischemia in canine heart and 20 min reperfusion on the function of the VSCC in the sarcolemma was examined in the presence or absence of 1.6 vol% halothane administered in vivo. The membranes were isolated through differential centrifugation/filtration from the ischemic (left anterior descending territory) and normally perfused myocardium. Comparison of binding characteristics in the ischemic and nonischemic zones was made using equilibrium-binding studies of a dihydropyridine calcium channel blocker, [3H]isradipine (0.05-1.0 nM), to the VSCC in the sarcolemma. Control studies were performed on membranes prepared from the same perfusion zones, but from hearts who were not exposed to ischemia.

RESULTS

The control studies (n = 5) showed no difference in binding kinetics between the different zones in the heart. After 10 min of ischemia, a 50 to 95% increase in specific [3H]isradipine binding to the sarcolemmal membranes was observed as compared to control membranes (P < 0.001). The maximal binding capacity (Bmax) increased by 85%, whereas the dissociation constant (Kd) remained unchanged. In the reperfusion experiments, a moderately increased binding (of 32%) was observed with a 40% increase in Bmax (P = NS). In the presence of 1.6% inhaled halothane, the effect of ischemia was attenuated. A decrease of 32.1% to 41.8% in equilibrium binding was observed (31% decrease in Bmax; P < 0.03 and 0.02, respectively).

CONCLUSIONS

Even a brief period of myocardial ischemia produces a marked increase in the available high-affinity binding sites in the VSCC, a finding that is well correlated with previous experimental observation of increased calcium ion influx to the myocardial cell. On reperfusion, some recovery of the ischemic changes in the VSCC was evident. The binding kinetics which characterize this early phase of cell injury were reversed by halothane anesthesia, indicating a possible reduction in calcium entry, which may represent one of the beneficial effects of the anesthetic in the ischemic heart.

Effect of halothane on sarcolemmal calcium channels during myocardial ischemia and reperfusion

The present results provide indirect support for other studies which showed that halothane inhibited the Ca2+ accumulation associated with myocardial ischemia in isolated guinea pig hearts (6), demonstrating a potentially beneficial effect of the anesthetic on the ischemic heart. The role of halothane in preventing ischemia-induced dysrhythmias and attenuation of free radical generation on reperfusion offers a new potential use during open heart surgery. The method of continuous perfusion of oxygenated blood cardioplegia, retrogradely, through the coronary sinus, enables a concomitant administration of the VA before and during the ischemic period of the cardiopulmonary bypass. Further studies may promote the use of the volatile anesthetic when myocardial ischemia and reperfusion are present during open heart surgery.

Warm blood cardioplegia for patients undergoing revascularization for left main coronary artery disease

Between February 1991 and June 1992, 62 patients (50 males) underwent coronary artery bypass (CAB) operation for significant left main coronary artery disease. Age varied between 47 and 81 years. 53 patients had unstable angina, 16 had recent myocardial infarction, and 16 had heart failure. 22 patients were in functional capacity class IV (Canadian Heart Association) and 2 patients were in unstable hemodynamical condition before the operation. Intraaortic balloon pump was inserted before the operation in 3 patients. Six patients had previous CAB surgery. All the patients were operated using myocardial protection with warm blood cardioplegia, given antegradely and retrogradely in 58 and only antegradely in 4 patients. Body temperature was maintained at 30 +/- 1.8 degrees C. Number of distal anastomoses averaged 4.3 +/- 0.9. One patient underwent additional resection of a left atrial myxoma and another aortic valve replacement. LIMA (left internal mammary artery) was used to bypass the LAD in 58 (94%) patients. Early mortality was 3 cases (4.8%). Major and minor postoperative complications occurred in 17 patients. These data suggest that warm blood cardioplegia provides superior myocardial protection in patients with left main coronary artery disease.

Dose-response effect of intrathecal alfentanil on canine lower urinary tract dynamics

The effect of intrathecal (IT) administration of three different doses (1, 2.5, and 5 micrograms/kg) of alfentanil on lower urinary tract dynamics was examined by urodynamic studies, cystometrograms (CMG), and urethral pressure profiles (UPP) in seven anesthetized dogs. Simultaneous serum drug concentrations were determined by specific radioimmunoassay for time-response analysis. A significant dose-dependent relaxation of urethral musculature expressed by a reduction in UPP values of 41.5% and 38.4% (P < 0.03) was noted 30 min after 5 and 2.5 micrograms/kg IT alfentanil, respectively, whereas the decrease of 13.4-22% in mean CMG values was not significant. All changes in UPP and CMG returned to baseline values by 60 min. The pharmacokinetics of alfentanil from the cerebrospinal fluid to the systemic circulation were linear, i.e., dose-independent with maximal serum concentrations of 0.6, 1.4, and 3.5 ng/mL 10 min after the three respective IT doses. The low serum alfentanil concentrations and the lack of time correlation between the peak values and the changes in urinary tract activity, point to a spinally mediated mechanism. The short-lived effect of IT alfentanil on lower urinary tract dynamics and the relaxation of the bladder neck allow for unobstructed micturition pathways and may avoid urinary retention.

Dose-response effect of intrathecal alfentanil on canine lower urinary tract dynamics

The effect of intrathecal (IT) administration of three different doses (1, 2.5, and 5 micrograms/kg) of alfentanil on lower urinary tract dynamics was examined by urodynamic studies, cystometrograms (CMG), and urethral pressure profiles (UPP) in seven anesthetized dogs. Simultaneous serum drug concentrations were determined by specific radioimmunoassay for time-response analysis. A significant dose-dependent relaxation of urethral musculature expressed by a reduction in UPP values of 41.5% and 38.4% (P < 0.03) was noted 30 min after 5 and 2.5 micrograms/kg IT alfentanil, respectively, whereas the decrease of 13.4-22% in mean CMG values was not significant. All changes in UPP and CMG returned to baseline values by 60 min. The pharmacokinetics of alfentanil from the cerebrospinal fluid to the systemic circulation were linear, i.e., dose-independent with maximal serum concentrations of 0.6, 1.4, and 3.5 ng/mL 10 min after the three respective IT doses. The low serum alfentanil concentrations and the lack of time correlation between the peak values and the changes in urinary tract activity, point to a spinally mediated mechanism. The short-lived effect of IT alfentanil on lower urinary tract dynamics and the relaxation of the bladder neck allow for unobstructed micturition pathways and may avoid urinary retention.

Depression of calcium channel blocker binding to rat brain membranes by halothane

The present study evaluates the action of volatile anesthetics on the voltage-dependent Ca2+ channels in isolated rat brain membranes, measured as changes in binding of the Ca2+ channel blocker [3H]isradipine to these membranes. Equilibrium binding studies with increasing concentrations of [3H]isradipine (0.01-1 nM) in the presence of halothane (1.9%), isoflurane (2.3%), and enflurane (4.8%) at 25 degrees C were performed. Only halothane produced a significant depression in the specific binding of isradipine to the brain membranes at 0.5 and 1.0 nM [3H]isradipine (P = 0.028 and 0.018, respectively). Isoflurane and enflurane had such inconsistent effects that the data were inconclusive. Halothane produced a significant dose-dependent inhibition of binding, the maximum inhibition being 44% (P less than 0.005). Nonlinear regression analysis fit of the binding data indicates halothane produced a 48% decrease (P less than 0.05) in the maximal number of binding sites (Bmax) with no effect on the dissociation constant (Kd). As voltage-dependent Ca2+ channels are important in mediating neurotransmission, the marked decrease in channel number (Bmax) associated with halothane exposure suggests that this phenomenon might be related to the mechanism of general anesthesia.

Spinal cord stimulation evoked potentials during thoracoabdominal aortic aneurysm surgery

Although monitoring of somatosensory evoked potentials elicited from stimulation of lower extremity peripheral nerves has been suggested as a method for assessing neural function during thoracoabdominal aortic aneurysm surgery, this technique has been reported to yield a large number of false positives. It was believed that direct stimulation of the spinal cord would eliminate some of the problems associated with peripheral evoked potentials. The present study compared in 18 patients the use of scalp recorded evoked potential following stimulation of either the posterior tibial nerve via percutaneous needles or the spinal cord via an epidural electrode previously placed fluoroscopically. In 10 patients in whom distal bypass or shunt was not used, peripheral evoked potentials totally disappeared within 5-30 min of aortic clamping. Spinal cord stimulation evoked potentials disappeared permanently in 2 patients shortly after aortic cross-clamping; 1 died shortly after the procedure, and the other awoke densely paraplegic and died the next day. When distal perfusion was maintained by shunt or bypass, the disappearance of both peripheral and spinal evoked potentials accurately predicted the neurologic outcome of 1 paralyzed patient. Loss of spinal cord stimulation evoked potentials was found to be correlated with adverse neurologic outcome. Over the period of aortic clamping a gradual decrease in mean amplitude (50% at 45 min [P less than 0.05]) and a 20% increase in mean latency time were observed. Maintenance of adequate distal perfusion may permit the use of peripheral evoked potentials in the assessment of spinal cord ischemia during aortic cross-clamping.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic localization of spinal cord blood supply and its relationship to postoperative paraplegia

Forty-seven patients underwent selective catheterization of middle and lower thoracic intercostal and upper lumbar arteries to define the origin of the artery of Adamkiewicz. One patient had significant atheroembolism, and a second had transient lower extremity paresthesias. No other complications occurred. The origin was found in 26 (55%), and 21 patients underwent thoracoabdominal aneurysm repair with this knowledge. When the critical lumbar or intercostal artery could be included as part of a long proximal or distal anastomosis, all 12 patients could be included as part of a long proximal or distal anastomosis, all 12 patients survived, and one was paralyzed. However, if the aneurysm repair mandated a midgraft anastomosis to intercostal arteries critical to spinal cord perfusion, seven of nine patients either died or were paralyzed (p less than 0.05). In the group of 19 patients operated on in whom spinal cord blood supply was not identified three patients had a technically unsuccessful operation; two died, and one was paralyzed. Twelve of 16 patients who had an adequate, but unsuccessful attempt at localization were treated by intercostal "neglect" and survived. Late paresis developed in two patients, but they are walking now. One of the patients who died had multiple systems failure and awakened paraplegic. She had a patent, enlarged, thoracic radicular artery at T-5 which probably supplied to spinal cord and which was missed angiographically. Paralysis was associated with aneurysm extent (group 2 and III B, dissections vs group 1 & 3, p less than 0.05). Selective intercostal angiography requires further refinement, but it is safe and offers the promise of understanding the mechanisms and risks of spinal cord complications after repair of extensive thoracoabdominal aneurysms.

Epidural methadone for analgesic management of patients with conservatively treated proximal femoral fractures

Epidural methadone analgesia was initiated soon after admission to emergency room in elderly patients who sustained osteoporotic proximal femoral fracture and who were considered to be high surgical risks. The severe pain was significantly reduced, enabling early mobilization of the patients. The analgesia was discontinued only when nonnarcotic analgesia sufficed. The treatment lasted for about 3.5 weeks. One minor complication was observed during the treatment period. We concluded that patients who have femoral neck fracture who are at high risk for operation and have to be observed and stabilized before operation can be managed by continuous epidural methadone analgesia.

Urodynamic studies after intrathecal fentanyl and buprenorphine in the dog

Cystometrograms (CMG) and urethral pressure profiles (UPP) were used in six anesthetized dogs to study the urodynamic effects of intrathecal (IT) injections of fentanyl and buprenorphine. The CMG and UPP were examined for each of the two drugs in all dogs (four experiments per animal). The measurements were performed before and 15, 30, 60, 90, and 120 min after IT injection of either 1.5 micrograms/kg fentanyl or 2 micrograms/kg buprenorphine. Fifteen minutes after IT injection of fentanyl, reduction in bladder tone was already noted, followed by decreases in mean peak vesical pressure of 48.3% +/- 6.0 (SE) (P less than 0.05) and mean peak urethral pressure of 38% +/- 3.0 (P less than 0.05) between 30 and 60 min after injection. These decreases, occurring in each experiment, gradually lessened at 90 and 120 min. The effects of IT buprenorphine, a partial opioid agonist, on bladder and urethral dynamics were inconsistent and non-significant in all studies. Disturbances of micturition observed clinically after spinal opioid administration may be related to the decrease in intravesical pressure and the resulting highly compliant bladder. Relaxation of the urethral musculature seen 15 min after IT fentanyl may prevent overdistension of the bladder and its associated complications.

Extradural bupivacaine and methadone for extracorporeal shock-wave lithotripsy

Combined extradural bupivacaine and methadone analgesia was investigated in 144 patients who underwent extracorporeal shock wave lithotripsy (ESWL). Patients were assigned randomly to one of three groups: group I--extradural 0.5% bupivacaine hydrochloride 0.75 mg kg-1; group II--extradural 0.1% methadone hydrochloride 4 mg after the bupivacaine; group III--as group II, plus a continuous extradural infusion of methadone 0.3 mg h-1 after operation. In all patients, only partial motor deficit occurred. During ESWL, patients who received extradural bupivacaine and methadone had significantly less pain compared with those who had bupivacaine alone (P less than 0.025). Extradural anaesthesia and immersion in the warm water bath were accompanied by only mild fluctuations in arterial pressure. After ESWL, significantly more patients with continuous methadone infusion were pain free (P less than 0.05) and they required less systemic analgesics. The anaesthesia during and after the ESWL procedure may be carried out safely and effectively by the administration of small doses of bupivacaine combined with methadone followed by infusion of the opioid.

Urodynamic studies after intrathecal administration of baclofen and morphine in dogs

The effects of intrathecally administered baclofen and morphine on the lower urinary tract dynamics of anesthetized dogs were investigated by means of cystometrogram and urethral pressure profile measurement. The experiments were performed prior to and 30, 60 and 90 minutes following intrathecal injection of either baclofen (0.03 mg./kg.), morphine (0.03 mg./kg.), or a mixture of the two (0.03 mg./kg. of each drug). Vesical pressure was significantly depressed after either baclofen (p less than 0.005) or morphine (p less than 0.005), while urethral pressure was decreased significantly only following baclofen (p less than 0.025). Administration of a baclofen/morphine admixture resulted in an additive reaction on the urethral pressure profile, compared with the changes brought about by each drug alone. Relaxation of the bladder and reduction in urethral resistance occurred 30 minutes post injection, increasing progressively after 60 and 90 minutes. The results demonstrated that baclofen, by its influence on cord neuron interaction, is capable of inhibiting the activity of the smooth muscle of the normal bladder and urethra, which in the case of the latter became more pronounced when both drugs were administered simultaneously by the intrathecal route.

Physostigmine and naloxone reverse the effect of intrathecal morphine on the canine urinary bladder

Cystometrograms and urethral pressure profiles were used in 11 anaesthetized dogs to study the urodynamic effects of intravenously administered physostigmine (Group I--seven dogs) and intravenously administered naloxone (Group II--four dogs) following intrathecal morphine. In four of these dogs (Group III) intravenous physostigmine preceded the intrathecal morphine injection. In Groups I and II, intrathecal morphine 0.03 mg kg-1 caused a significant relaxation of the detrusor P less than 0.05), as expressed by a fall of 34.2 +/- 4.4% (SE) in mean intravesical pressure and a rise of 57 +/- 12.7% (SE) in calculated detrusor compliance at 90 min. Both physostigmine, 0.1 mg kg,-1 and naloxone, 0.025 mg kg,-1 given at this time completely abolished the influence of the narcotic on the bladder without changing urethral pressures. In Group III, physostigmine produced a marked rise in intravesical pressure (P less than 0.01) that was reversed by subsequent morphine. It is of interest that physostigmine, a potent cholinergic agent, and naloxone, a pure opiate antagonist, exert a similar action on bladder function.

Attenuation of ocular and systemic responses to tracheal intubation by intravenous lignocaine

This study was undertaken to determine whether intravenous lignocaine could mitigate or prevent the ocular reactions and especially the acute increase in intraocular pressure associated with laryngoscopy and tracheal intubation. Two groups of children undergoing minor eye surgery under nitrous oxide-oxygen-halothane anaesthesia were examined. The experimental group (n = 17) received 2 mg/kg lignocaine and the controls (n = 18) an equivalent volume of saline. The incidence of local laryngeal and ocular reflexes was much lower in the lignocaine group. Pulse acceleration was significantly lower in the lignocaine group (p less than 0.025), and the maximal mean intraocular pressure was significantly less than in the control group (p less than 0.005). Other ocular reactions were recorded, and all were attenuated after lignocaine administration. The beneficial effects of lignocaine, a suppressant of autonomic reflexes, suggest that intraocular pressure, like the heart rate, rises after intubation as a result of autonomic stimulation. The use of intravenous lignocaine is thus recommended for children at risk, such as those needing an urgent operation because of lacerated eye injury under rapid sequence induction of anaesthesia.

Ruptured inflammatory abdominal aortic aneurysm due to acute myelomonoblastic leukemia

The extremely rare case of ruptured abdominal aortic aneurysm of inflammatory nature in patient with discovered acute myelomonoblastic leukemia is presented. The difficult problems arising from these, frequently terminal diseases, are discussed.

Severe upper airway obstruction and difficult intubation in cicatricial pemphigoid

Upper airway obstruction in cicatricial pemphigoid is rarely seen by the anaesthetist. A case of severe dyspnoea due to progressive laryngeal obstruction is presented. Tracheal intubation during induction of general anaesthesia for permanent tracheostomy was extremely difficult and was successfully performed by introducing a size 12 French suction catheter through the stenotic laryngeal orifice. Adequate ventilation was achieved by using the oxygen flush valve to deliver oxygen intermittently through the catheter.

The action of intrathecal morphine and methadone on the lower urinary tract in the dog

The effects of intrathecally administered morphine and methadone on lower urinary tract dynamics were investigated by cystometrograms and urethral pressure profiles in 16 anesthetized dogs. The examinations were performed before and 30, 60 and 90 minutes following intrathecal injection of 0.03 mg./kg. morphine or methadone. Intrathecal normal saline was used for control studies. Significant relaxation of the detrusor was noted after intrathecal morphine as expressed by a decrease in mean intravesical pressure (p less than 0.05) and by a rise in the calculated detrusor compliance. These effects were reversed by intravenously injected naloxone. As opposed to morphine, methadone caused an increase in detrusor tone. No appreciable effects were observed on the urethra after intrathecal morphine or methadone. Neither intravenous injection of the opiates nor intrathecal administration of saline caused alterations in bladder tone. The result may imply a spinal, albeit opposing, effect of the two opiates on bladder dynamics.

Intraocular pressure variation during strabismus surgery

The changes in IOP during strabismus surgery were studied in 40 patients. In most, 37 eyes, there was a marked decrease of IOP during surgery and rapid return to initial levels of IOP. In 13 out of 14 eyes that underwent bilateral surgery, the IOP in the first operated eye returned to about baseline levels by the end of surgery on the second eye. No correlation was found between the changes in IOP and: the type of surgery, the operated muscles, the duration of surgery and anesthesia, or the patients' age. We surmise that the decrease of IOP is probably associated with the intensity of the massage of the globe during the surgery.

Erythroderma and pneumonitis induced by penicillin?

Penicillin and its derivatives are known to cause several dermatologic and pulmonary hypersensitivity reactions. This report describes a patient who presented with combined generalized exfoliative dermatitis and severe pneumonitis caused by penicillin and aggravated by ampicillin, methicillin and mezlocillin. Antibiotic challenges with penicillin caused immediate reappearance of the dermatological manifestation; reactivation of the pneumonitis was probably prevented by immediate discontinuation of the drug.