Effect of intra-operative intravenous lidocaine on opioid consumption after bariatric surgery: a prospective, randomised, blinded, placebo-controlled study

Peri-operative lidocaine infusion warrants investigation in bariatric surgery because obese patients present different physiological and pharmacological risks. This single-centre, prospective, randomised double-blind placebo-controlled study enrolled obese patients scheduled for laparoscopic bariatric surgery using an enhanced recovery protocol. Patients received either lidocaine (bolus of 1.5 mg.kg^-1 , then a continuous infusion of 2 mg.kg^-1 .h^-1 until the end of the surgery, then 1 mg.kg^-1 .h^-1 for 1 h in the recovery area) or identical volumes and rates of 0.9% saline. The primary outcome was the consumption of the equivalent of oxycodone consumption over the first 3 postoperative days. Secondary outcomes were: postoperative pain; incidence of nausea and vomiting; bowel function recovery; and lengths of stay in the recovery area and in hospital. Plasma concentrations of lidocaine were measured. On the 178 patients recruited, data were analysed from 176. The median (IQR [range]) equivalent intravenous oxycodone consumption was 3.3 mg (0.0-6.0 [0.0-14.5]) and 5.0 mg (3.3-7.0 [3.3-20.0]) in the lidocaine and saline groups, respectively (difference between medians (95%CI): 1.7 (0.6-3.4) mg; p = 0.004). Length of stay in the recovery area, postoperative pain, nausea and vomiting, day of recovery of bowel function, and length of stay in hospital were not different between groups. Mean (SD) lidocaine plasma concentrations were 2.44 (0.70) µg.ml^-1 and 1.77 (0.51) µg.ml^-1 at the end of surgery and 1 hour after the end of infusion, respectively. Lidocaine infusion during bariatric surgery resulted in a clinically non-relevant difference in postoperative oxycodone consumption.

Influence of bacterial resistance on mortality in intensive care units: a registry study from 2000 to 2013 (IICU Study)

BACKGROUND

Bacterial resistance to antibiotics is a daily concern in intensive care units. However, few data are available concerning the clinical consequences of in-vitro-defined resistance.

AIM

To compare the mortality of patients with nosocomial infections according to bacterial resistance profiles.

METHODS

The prospective surveillance registry in 29 French intensive care units (ICUs) participating during the years 2000-2013 was retrospectively analysed. All patients presenting with a nosocomial infection in ICU were included.

FINDINGS

The registry contained 88,000 eligible patients, including 10,001 patients with a nosocomial infection. Among them, 3092 (36.7%) were related to resistant micro-organisms. Gram-negative bacilli exhibited the highest rate of resistance compared to Gram-positive cocci (52.8% vs 48.1%; P < 0.001). In-hospital mortality was higher in cases of patients with antibiotic-resistant infectious agents (51.9% vs 45.5%; P < 0.001), and critical care length of stay was longer (33 ± 26 vs 29 ± 22 days; P < 0.001). These results remained significant after SAPS II matching (P < 0.001) and in the Gram-negative bacilli and Gram-positive cocci subgroups. No difference in mortality was found with respect to origin prior to admission.

CONCLUSION

Patients with bacterial resistance had higher ICU mortality and increased length of stay, regardless of the bacterial species or origin of the patient.

Desflurane-induced postconditioning of diabetic human right atrial myocardium in vitro

AIM

We tested the hypothesis that brief exposure to desflurane at the time of reoxygenation might be able to protect against hypoxia-reoxygenation injury in human myocardium from diabetic (insulin-dependent, ID; and non-insulin-dependent, NID) patients and non-diabetic (ND) subjects.

METHODS

The force of contraction (34 degrees C, stimulation frequency 1Hz) in the right atrial trabeculae was recorded during 30min of hypoxia followed by 60min of reoxygenation. Desflurane (at 3, 6 and 9%) was administered during the first 5min of reoxygenation. The force of contraction at the end of the 60-min reoxygenation period (FoC(60)) was compared in the study groups (means+/-SD).

RESULTS

In the ND group, desflurane at 3, 6 and 9% (FoC(60): respectively 78+/-10%, 84+/-4% and 85+/-12% of baseline) enhanced the recovery of FoC(60) compared with the ND-controls (53+/-7% of baseline; P<0.05). In the ID group, desflurane at 3% (61+/-4%) did not modify the recovery of FoC(60) compared with the ID-controls (54+/-6%), whereas desflurane at 6 and 9% (75+/-11% and 81+/-8%, respectively) enhanced the recovery of FoC(60)vs the controls (P<0.05). In the NID group, desflurane at 3% (57+/-5%) also failed to modify the recovery of FoC(60) compared with the NID-controls (52+/-10%), while desflurane at 6 and 9% (80+/-10% and 79+/-7%, respectively) enhanced the recovery of FoC(60)vs the controls (P<0.05).

CONCLUSION

Desflurane in vitro was able to postcondition diabetic (both ID and NID) human myocardium at 6 and 9%, but not at 3%.

Hypothermie après rachianesthésie : rôle de la morphine ?

Spinal anaesthesia is the gold standard for elective caesarean section. This technique presents several adverse effects. We report a severe case of hypothermia (33.3 degrees C) after spinal administration of bupivacaine (10 mg) and morphine (100 microg) for elective caesarean section. After excluding other causes of hypothermia, this one could be explained by both the own effects of local anaesthesia (i.e. peripheral vasodilatation) and by the central effect of intrathecal morphine. Because hypothermia is not predictable after spinal injection of morphine both monitoring of central temperature and active warming of the patients could be proposed. Naloxone has been proposed in a case of hypothermia related to spinal injection of morphine.

Cardioprotective effects of desflurane: effect of timing and duration of administration in rat myocardium

BACKGROUND

We compared the cardioprotective effects of 1 minimum alveolar concentration (MAC) desflurane administered before, during or after ischaemia, or throughout the experiment (before, during and after ischaemia) on myocardial infarct size following 30 min occlusion of the left anterior descending coronary artery and 3 h reperfusion in adult rats.

METHODS

Fifty male Sprague-Dawley rats were anaesthetized with pentobarbital, intubated and mechanically ventilated. Blood gases, pH and body temperature (37.5-38 degrees C) were controlled. Heart rate and arterial pressure were measured continuously. Animals were randomly assigned to the following groups (n=10 in each group): pentobarbital only ("Pento"); 15 min desflurane administration followed by 10 min of washout before 30 min ischaemia and 3 h reperfusion ("Precond"); 30 min desflurane administration during ischaemia period ('Isch'); desflurane administration during the 15 first min of reperfusion ("Reperf") and desflurane administration throughout the experiment (before, during and after ischaemia; "Long"). Volumes at risk and infarct sizes were assessed by Indian ink and with 2,3,5-triphenyltetrazolium chloride staining, respectively.

RESULTS

Physiological parameters and volumes at risk were not significantly different between groups. In the Pento group, mean myocardial infarct size was 65 (sd 15)% of the volume at risk; myocardial infarct size was reduced to a significant and comparable extent in the desflurane-treated groups (Precond 42 (14)%; Isch 34 (11)%; Reperf 41 (15)%; Long 33 (10)%; P<0.0002 vs Pento group).

CONCLUSIONS

In rats, desflurane 1 MAC significantly decreased myocardial infarct size whatever the period and duration of administration.

Desflurane affords greater protection than halothane against focal cerebral ischaemia in the rat

BACKGROUND

We studied the potential neuroprotective effects of halothane and desflurane, compared with the awake state, on infarct size following 2 h of intraluminal middle cerebral artery occlusion (MCAo) and 22 h of reperfusion.

METHODS

Male Sprague-Dawley rats were anaesthetized with desflurane or halothane, intubated, and mechanically ventilated. Mean arterial pressure (MAP), blood gases, and pH were controlled. Body temperature was maintained at 37.5-38 degrees C. Animals were assigned to one of four groups according to the anaesthetic type (halothane or desflurane) and the duration of anaesthesia: "short-duration", during the preparation only; "long-duration", during both preparation and ischaemia. Twenty-four hours after MCAo, infarcts were visualized by staining with 2,3,5-triphenyltetrazolium chloride. Two additional groups of rats were subjected to the same protocol as that of long-duration halothane and long-duration desflurane with additional pericranial temperature measurements made.

RESULTS

Physiological parameters were comparable between the groups but MAP was higher (P<0.0001) in the short-duration groups. In the short-duration groups, cerebral infarct volumes were not significantly different between anaesthetics (short-duration halothane: 288 (61) mm(3), mean (SD); short-duration desflurane: 269 (71) mm(3), P>0.56). Compared with the awake state (short-duration groups), halothane and desflurane significantly reduced infarct volumes (long-duration halothane: 199 (54) mm(3), P<0.0047 vs short-duration halothane; long-duration desflurane: 121 (55) mm(3), P<0.0001 vs short-duration desflurane). The mean infarct volume in the long-duration desflurane group was significantly lower than that in the long-duration halothane group (P<0.0053). Pericranial temperatures were similar in the desflurane and halothane long-duration groups (P>0.17).

CONCLUSIONS

In rats, desflurane-induced neuroprotection against focal cerebral ischaemia was greater than that conferred by halothane.

[Vasodilatory septic shock refractory to catecholamines: is there a role for terlipressin?]

We report two patients in vasodilatory septic shock refractory to catecholamines in which a continuous infusion of terlipressin was associated with a dramatic increase in systemic arterial blood pressure and short-term survival. Low doses of terlipressin were sufficient in both cases (0.01-0.0 mg h(-1)) to restore blood pressure by increase of systemic vascular resistances. The haemodynamic response was immediate, long-acting, dose-dependent and reversible in a few hours when the drug administration was stopped. A further increase in terlipressin dose regimen markedly decreased cardiac performance. Terlipressin simultaneously induced vasoconstriction within the cutaneous vascular territory, leading to local skin necrosis. The splanchnic vascular territory seemed to be constricted in the same way. Further studies are needed to better understand and precise the role of terlipressin in the treatment of vasodilatory septic shock refractory to catecholamines.

[Feasibility of ambulatory endovenous laser for the treatment of greater saphenous varicose veins: one-month outcome in a series of 20 outpatients]

The purpose of this feasibility study was to demonstrate that endovenous laser can be a useful alternative to conventional surgery for ambulatory treatment of advanced varicose veins. We assessed an open, non-randomized series of patients treated in one center by the same operator. The study protocol was approved by the local ethics committee. Twenty patients with stage II or III varicose veins in the Porter classification gave their informed consent to participate in the study. The patients were treated with endovenous laser by the first author in the outpatient clinic of the Henri Mondor University Hospital vascular surgery department. All procedures were conducted under local anesthesia. A 980 nm laser diode optic fiber was introduced into the vein percutaneously. Laser beams were fired from the sapheno-femoral junction to just under the genu, withdrawing the fiber 3 mm every 1.5 sec. Clinical evaluation with a quality-of-life questionnaire and duplex-scan was performed at days 3, 8 and 30 post-op. Complete occlusion and retraction of the treated vein was observed at day 3 and 30, from the point of introduction to the sapheno-femoral junction in 18 of the 20 patients. The branches of the greater saphenous vein remained patent with physiological flow in the stump which remained patent 1 to 2 cm upstream from the sapheno-femoral junction. The length of the patent stump dependend on the level of the anterior or posterior branch. There were no adverse effects related to the local anesthesia. Pain was low to mild during treatment and the days following the procedure, requiring 8 tablets of acetominophen at most. Hematomas were minimal and had completely resolved by the end of the first month. No work stoppage was required for the 14 patients with occupational activities. There were no cases of deep or superficial vein thrombosis. Complete occlusion and retraction of the varicose vein at one month suggests this treatment has a long-lasting effect. Long-term evaluation is required. Treatment of advanced varicose veins with endovenous laser can be an alternative to surgical treatment providing the advantage of outpatient ambulatory treatment.

The in vitro effects of remifentanil, sufentanil, fentanyl, and alfentanil on isolated human right atria

Because some clinical studies have suggested that opioids used in anesthesia may have different deleterious hemodynamic effects, we compared the direct myocardial effects of cumulative concentrations of remifentanil, sufentanil, fentanyl, and alfentanil on inotropic and lusitropic variables of isolated human myocardium in vitro. Human right atrial trabeculae, obtained from patients scheduled for coronary bypass surgery or aortic valve replacement, were suspended vertically in an oxygenated (95% oxygen/5% CO(2)) Tyrode's modified solution ([Ca(2+)](o) = 2.0 mM, 37 degrees C, pH 7.40, stimulation frequency 1 Hz). The effects of cumulative concentrations (10(-11), 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) M) of remifentanil (n = 8), sufentanil (n = 8), fentanyl (n = 8), and alfentanil (n = 8) on inotropic and lusitropic variables of isometric twitches were measured. Remifentanil, sufentanil, and fentanyl did not modify active isometric force and peak of the positive force derivative as compared with the Control group. Alfentanil induced a dose-dependent decrease in active isometric force and peak of the positive force derivative. This effect was abolished in the presence of [Ca(2+)](o) = 4.0 mM. None of these opioids altered lusitropic variables.

The in vitro effects of remifentanil, sufentanil, fentanyl, and alfentanil on isolated human right atria

Because some clinical studies have suggested that opioids used in anesthesia may have different deleterious hemodynamic effects, we compared the direct myocardial effects of cumulative concentrations of remifentanil, sufentanil, fentanyl, and alfentanil on inotropic and lusitropic variables of isolated human myocardium in vitro. Human right atrial trabeculae, obtained from patients scheduled for coronary bypass surgery or aortic valve replacement, were suspended vertically in an oxygenated (95% oxygen/5% CO(2)) Tyrode's modified solution ([Ca(2+)](o) = 2.0 mM, 37 degrees C, pH 7.40, stimulation frequency 1 Hz). The effects of cumulative concentrations (10(-11), 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) M) of remifentanil (n = 8), sufentanil (n = 8), fentanyl (n = 8), and alfentanil (n = 8) on inotropic and lusitropic variables of isometric twitches were measured. Remifentanil, sufentanil, and fentanyl did not modify active isometric force and peak of the positive force derivative as compared with the Control group. Alfentanil induced a dose-dependent decrease in active isometric force and peak of the positive force derivative. This effect was abolished in the presence of [Ca(2+)](o) = 4.0 mM. None of these opioids altered lusitropic variables.

[Intraoperative memory. A study of its incidence in general anesthesia in 326 patients]

OBJECTIVES

Measuring the incidence of intraoperative recall in our hospital.

STUDY DESIGN

Prospective study.

PATIENTS AND METHODS

Three hundred and twenty-six patients who underwent a general anaesthesia for elective surgery on selected sites (general, urology, ORL, gynaecology and obstetrical, vascular and cardiac, thoracic) were interviewed on the first or the second postoperative day using a standard questionnaire. When recall was suspected, the anaesthetist was consulted and the anaesthetic record was looked at in order to evaluate the authenticity of any recollections.

RESULTS

Four patients mentioned an anomaly evoking intra-operative recall. The reduction in the anaesthetic level would explain authentic recollection for one patient. The recollection of another patient could not be truly verified. The site was the same for these two cases and the anaesthetic protocol for digestive surgery comprised curare and droperidol. The recollections for the two other patients did not correspond to the intraoperative period. The incidence of this phenomenon on the totality of sites was 0.6 per cent.

CONCLUSION

This result conforms to other studies. This phenomenon is a quality indicator, but probably under estimated. Although retrospective, this evaluation is quick and easy. This research in post-operative period should be systematic in order to find the reason and to propose an early course of action for these patients. An analysis of the anaesthetic protocol is necessary when the frequency of intraoperative recall is too high.

Delayed diagnosis of vascular injuries during lumbar discectomy

We report an accidental perforation of the left iliac artery and vein during lumbar discectomy in the kneeling position. During the surgical procedure, a brief and transient hypotension occurred, although the surgeon did not observe any abnormal bleeding in the operating field. In the recovery room, arterial blood pressure decreased, and tachycardia, pallor, and abdominal pain occurred. Retroperitoneal bleeding was suspected. Immediate fluid resuscitation was initiated, anesthesia was continued, and red blood cells were ordered. The use of medical antishock trousers enabled temporization until vascular surgeons were ready. An emergent laparotomy was performed to repair vascular injuries. The delayed symptoms, use of medical antishock trousers, and implications for anesthetists are discussed.

Electrophysiological effects of dofetilide in an in vitro model of "border zone" between normal and ischemic/reperfused myocardium

BACKGROUND

To evaluate both class III activity and antiarrhythmic action of dofetilide at the level of the "border zone," we investigated its electrophysiological effects on guinea pig ventricular strips submitted partly to normoxia (normal zone, NZ) and partly to simulated severe ischemia, then reperfusion (altered zone, AZ).

METHODS AND RESULTS

Because of the differential class III effects of dofetilide in normal and ischemic regions, the dispersion of the action potential duration at 90% repolarization (APD(90)) between NZ and AZ was reduced by 5 nmol/L of drug during early ischemia (at 10 minutes, APD(90) NZ/APD(90) AZ was 1.68+/-0.22 versus 2.82+/-0.17 in control, P<0.05), whereas 50 nmol/L dofetilide worsened it during late ischemia (at 30 minutes, APD(90) NZ/APD(90) AZ was 4.62+/-0.76 versus 2.57+/-0.21 in control, P<0.05). Concomitantly, dofetilide at 5, 10, and 50 nmol/L abolished the early extrastimulus (ES)-induced arrhythmias, and at 10 and 50 nmol/L, it significantly enhanced the incidence of late spontaneous repetitive responses (in 86% and 75% of preparations treated with 10 and 50 nmol/L, respectively, versus 25% in control, P<0.05). During reperfusion, dofetilide at 5, 10, and 50 nmol/L exhibited concentration-dependent class III effects, as it did in the NZ, and did not modify the incidence of spontaneous arrhythmias.

CONCLUSIONS

Dofetilide 5 nmol/L decreased APD(90) dispersion between NZ and AZ and reduced the early ES-induced arrhythmias. However, dofetilide 50 nmol/L increased APD(90) dispersion, and at 10 and 50 nmol/L, it increased the late spontaneous arrhythmias.

[Mesenteric vein and inferior vena cava thrombosis: disseminated intravascular coagulation and/or G 20210 A mutation of the prothrombin gene?]

The authors report the case of a 30-year-old man who died from pulmonary embolism and multiorgan failure caused by mesenteric and inferior vena cava thrombosis. The patient was found heterozygous for the prothrombin gene variant (G 20210 A). The family study showed the same asymptomatic anomaly in his brother. This recently described mutation is associated with an increased risk for venous thrombosis. The investigations and treatment of mesenteric venous thrombosis are discussed.

In vitro effects of desflurane, sevoflurane, isoflurane, and halothane in isolated human right atria

BACKGROUND

Direct myocardial effects of volatile anesthetics have been studied in various animal species in vitro. This study evaluated the effects of equianesthetic concentrations of desflurane, sevoflurane, isoflurane, and halothane on contractile parameters of isolated human atria in vitro.

METHODS

Human right atrial trabeculae, obtained from patients undergoing coronary bypass surgery, were studied in an oxygenated (95% O2-5% CO2) Tyrode's modified solution ([Ca2+]o = 2.0 mM, 30 degrees C, stimulation frequency 0.5 Hz). The effects of equianesthetic concentrations (0.5, 1, 1.5, 2, and 2.5 minimum alveolar concentration [MAC]) of desflurane, sevoflurane, isoflurane, and halothane on inotropic and lusitropic parameters of isometric twitches were measured.

RESULTS

Isoflurane, sevoflurane, and desflurane induced a moderate concentration-dependent decrease in active isometric force, which was significantly lower than that induced by halothane. In the presence of adrenoceptor blockade, the desflurane-induced decrease in peak of the positive force derivative and time to peak force became comparable to those induced by isoflurane. Halothane induced a concentration-dependent decrease in time to half-relaxation and a contraction-relaxation coupling parameter significantly greater than those induced by isoflurane, sevoflurane and desflurane.

CONCLUSIONS

In isolated human atrial myocardium, desflurane, sevoflurane, and isoflurane induced a moderate concentration-dependent negative inotropic effect. The effect of desflurane on time to peak force and peak of the positive force derivative could be related to intramyocardial catecholamine release. At clinically relevant concentrations, desflurane, sevoflurane, and isoflurane did not modify isometric relaxation.

KATP channels and 'border zone' arrhythmias: role of the repolarization dispersion between normal and ischaemic ventricular regions

1. In order to investigate the role of KATP channel activation and repolarization dispersion on the 'border zone' arrhythmias induced by ischaemia-reperfusion, the effects of glibenclamide and bimakalim, agents modifying action potential (AP) duration, were studied in an in vitro model of myocardial 'border zone'. 2. The electrophysiological effects of 10 microM glibenclamide and 1 microM bimakalim (n=8 each), respectively KATP channel blocker and activator, were investigated on guinea-pig ventricular strips submitted partly to normal conditions (normal zone, NZ) and partly to simulated ischaemic then reperfused conditions (altered zone, AZ). 3. By preventing the ischaemia-induced AP shortening (P<0.0001), glibenclamide reduced the dispersion of AP duration 90% (APD90) between NZ and AZ (P<0.0001), and concomitantly inhibited the 'border zone' arrhythmias induced by an extrastimulus (ES), their absence being significantly related to the lessened APD90 dispersion (chi2=8.28, P<0.01). 4. Bimakalim, which also reduced the APD90 dispersion (P<0.005) due to differential AP shortening in normal and ischaemic tissues, decreased the incidence of myocardial conduction blocks (25% of preparations versus 83% in control, n=12, P<0.05) and favoured 'border zone' spontaneous arrhythmias (75% of preparations versus 25% in control, P<0.05). 5. During reperfusion, unlike bimakalim, glibenclamide inhibited the ES-induced arrhythmias and reduced the incidence of the spontaneous ones (12% of preparations versus 92% in control, P<0.05), this latter effect being significantly related (chi2=6.13, P<0.02) to the lessened ischaemia-induced AP shortening in the presence of glibenclamide (P<0.0001). 6. These results suggest that KATP blockade may protect the ischaemic-reperfused myocardium from 'border zone' arrhythmias concomitantly with a reduction of APD90 dispersion between normal and ischaemic regions. Conversely, KATP channel activation may modify the incidence of conduction blocks and exacerbate the ischaemia-induced 'border zone' arrhythmias.

[Echo-doppler surveillance of revascularization of the legs in asymptomatic postoperative patients. Why? With what rhythm? How much time? How?]

AIM

Routine duplex surveillance of patients following an arterial operation includes the scanning of symptomless patients. While the benefits of preventive correction of deteriorations, stenoses or dilatations, following aortic or lower limb arterial reconstruction are undisputed, there is no hard data on the effectiveness of this surveillance in terms of limb salvage, on its cost, and on the optimal frequency and duration.

METHODS

The AA review the literature on this subject and suggest a programme which reconciles the patients' interests with the best use of health care financial resources.

RESULTS

The possible complications depend on the type of operation. Some are symptomless. They occur mainly during the first year and less frequently, but regularly so, during the subsequent years. There is therefore no time limit for the duration of the surveillance. The effectiveness of this surveillance is low and thus the examination must be meticulous and its frequency adapted to the risks. Broadly speaking: During the first year, aorto-ilio-femoral reconstructions must be screened at one month, six months and one year; by-passes below the groin with no particular risk at six months and one year; by-passes at risk and those anastomosed to a lower leg or ankle artery require a further check-up at one month and three months. After the first year, aorto-ilio-femoral and similar by-passes must be checked annually; by-passes below the groin, when at risk, must be checked annually; in those without any particular risk, a check-up every two years seems to be sufficient. Any patient found to have a deterioration on screening must be checked every six months.

CONCLUSION

Careful screening is the only way of discovering a symptomless deterioration before the development of serious complications. As every arteriole reconstruction should be followed by a lifelong surveillance, in times of financial constraints the frequency of the check-ups must be tailored according to the risks present and the quality of the surveillance must be faultless.

[Traumatic rupture of the pericardium. A rare diagnosis]

Rupture of the pericardium is a rare complication of blunt chest trauma. The diagnosis is difficult and if it remains unrecognized, severe complications such as heart herniation may occur. We report the case of a 19-year-old patient with a traumatic rupture of the pericardium. The diagnosis was suggested by a pneumopericardium seen on the chest radiograph and CT-scan. Emergency thoracotomy enabled localisation of the tear, assessment of its size, and reparation of the tear to prevent heart herniation.

KATP channel modulators and myocardial damages induced by ischemia-reperfusion: membrane lipids injury and arrhythmias

Although KATP channels have been proposed as playing a role in most types of myocardial damage associated with ischemia/reperfusion, the potential benefits of KATP channel modulators against the biochemical and electrical disturbances observed during ischemia remain unclear. We have thus studied the effects of glibenclamide and cromakalim, KATP channel blocker and opener respectively, on membrane lipid injury and arrhythmias, in a model of ischemic-reperfused guinea-pig myocardium. Ventricular strips were prelabeled with [3H] arachidonic acid, then subjected to normal conditions (Time-related Control) or to simulated ischemic-reperfused conditions in absence of drug (Control) or in presence of glibenclamide 10 microM or cromakalim 10 microM. The release of radioactive compounds was counted by liquid scintillation spectrometry, while action potentials (AP) were recorded with intracellular microelectrodes. Reperfusion induced a significant increase of arachidonic acid release (P < 0.05 versus Time-related Control). Glibenclamide inhibited the reperfusion-induced arachidonic acid release while cromakalim only delayed it (respectively 483 +/- 87 dpm/g, P < 0.05 and 790 +/- 143 dpm/g. NS versus 838 +/- 80 dpm/g for Control, after 30 min of reperfusion). Unlike glibenclamide, cromakalim was proarrhythmic during reperfusion (in 100% of preparations versus 33% in Control or in presence of glibenclamide, P < 0.05). This in vitro study shows that glibenclamide prevented the reperfusion-induced membrane arachidonic acid release, without proarrhythmic effect, whereas cromakalim, associated with proarrhythmicity, was unable to protect myocardium from cell lipid damage.

Proarrhythmic and antiarrhythmic effects of bupivacaine in an in vitro model of myocardial ischemia and reperfusion

BACKGROUND

Bupivacaine may have toxic cardiovascular effects when accidentally administered by intravascular injection. However, its electrophysiologic effects in the presence of myocardial ischemia remain unknown. The authors evaluated the electrophysiologic and anti- and proarrhythmic effects of bupivacaine in an in vitro model of the ischemic and reperfused myocardium.

METHODS

In a double-chamber bath, a guinea pig right ventricular muscle strip was subjected partly to normal conditions and partly to simulated ischemia followed by reperfusion. The electrophysiologic effects of bupivacaine were studied at 1, 5, and 10 microM concentrations.

RESULTS

Bupivacaine (5 and 10 microM) decreased the maximal upstroke velocity of the action potential (Vmax) in normoxic conditions and further decreased (10 microM) the Vmax decrease induced by ischemic conditions. Bupivacaine reduced the mean occurrence time to the onset of myocardial conduction blocks (9 +/- 3 min; mean +/- SD; P < 0.005 with 5 and 10 microM, compared with 17 +/- 6 min during simulated ischemia with no drug or control), and it increased the number of preparations that became inexcitable to pacing (55% of preparations, with 1 microM and 100% with 5 and 10 microM, compared with 17% for the control group). The incidence of spontaneous arrhythmias was reduced by 5 and 10 microM bupivacaine during ischemia and reperfusion and was enhanced by 1 microM bupivacaine during the ischemic phase.

CONCLUSIONS

In guinea pig myocardium under ischemic conditions, bupivacaine induced a loss of excitability at concentrations of 5 and 10 microM. Proarrhythmic effects observed at 1 microM were considered as lower than the cardiotoxic range in normoxic conditions. The incidence of reperfusion arrhythmias was decreased at all concentrations.

Proarrhythmic effects of DL- and D-sotalol on the "border zone" between normal and ischemic regions of isolated ventricular myocardium and antiarrhythmic effects on reperfusion

Considering the Survival With ORal D-sotalol (SWORD) study results, in which mortality was higher in patients treated by the pure class III agent D-sotalol, we tested DL- and D-sotalol (5 and 10 microM) in an in vitro model of "border zone" arrhythmias. Isolated guinea-pig ventricular strips were partly exposed to normoxia ("Normal Zone," NZ) and partly to modified Tyrode's solution ("Ischemic Zone," IZ) for 15 or 30 min ("ischemia"), followed by return to normoxia for 30 min ("reperfusion"). Resting membrane potential, action potential (AP) amplitude, and maximal upstroke velocity of AP were not significantly modified. DL- And D-sotalol, 5 and 10 microM, lengthened AP duration 90% (APD90) in NZ (p < 0.05), whereas these drugs were unable to prevent ischemia-induced APD shortening. By using the accelerated failure time Weibull's model, and a large number of reference experiments to control random variability of analyzed covariates, DL- and D-sotalol increased significantly the incidence of spontaneous arrhythmias during ischemia (chi2 = 24.79; p = 0.0367): 83 (5 microM D- and DL-sotalol), 86, and 62% (10 microM D- and DL-sotalol, respectively) versus 32% of controls. During reperfusion, 10 microM DL-sotalol prevented the occurrence of spontaneous arrhythmias (chi2 = 46.74; p = 0.0001) similar to what seen with the beta-blocking agent propranolol (10 microM). These data, providing evidence for proarrhythmic effects of DL- and D-sotalol on border-zone arrhythmias, concomitant with differential class III actions on NZ versus IZ, might be considered for understanding the SWORD study results.

Pulsed transthrombotic fibrinolysis: technique and results in the management of occluded lower limb bypass grafts

Between March 1987 and March 1993 we used pulsed transthrombotic fibrinolysis to treat 58 symptomatic thrombotic occlusions of lower limb bypass grafts in 45 patients. There were 17 suprainguinal grafts and 28 infrainguinal grafts. Treatment consisted of pulsed infusion of fibrinolytic agents into the thrombus followed by continuous infusion using an electric pump. Minor percutaneous or surgical procedures were often associated. The mean delay to treatment was 7 days. The mean duration of treatment was 150 +/- 66 minutes. Immediate patency was achieved in 88% of cases with no significant difference between suprainguinal and infrainguinal grafts. The clinical success rate was 55%. Actuarial patency at 1 year was 54% +/- 11% for suprainguinal grafts and 26% +/- 7% for infrainguinal grafts. The probability of patency was much lower in patients whose grafts had been implanted within 3 months before occlusion and in patients in whom an adjuvant procedure had not been performed. This study demonstrates that, in cases not requiring immediate surgery, pulsed transthrombotic fibrinolysis can achieve durable patency by treating both the bypass and distal arterial network. This technique allows identification of lesions causing thrombosis and adaptation of treatment specifically to these lesions.

[Associated carotid and coronary lesions: carotid endoluminal angioplasty before coronary surgery]

OBJECTIVE

There is debate over the therapeutic strategy in patients with lesions of both the coronary arteries and the carotid arteries. Improvement in angioplasty techniques for the carotid artery would be a minimally invasive alternative.

METHODS

Between January 1993 and June 1995, 12 patients who underwent endoluminal angioplasty of the carotid artery before coronary bypass surgery (mean 17.9 days before) were included in the study. Mean age was 70 +/- 3.2 years. The carotid lesions were asymptomatic in all patients who had stable angina.

RESULTS

The mean number of bypasses was 2.9 per patient. Five patients had a contralateral stenosis of the internal carotid artery. Angioplasty was performed under cerebral protection using a three way coaxial catheter. A Strecker stent was required in 8 cases. One patient presented transient hemianopsia. All patients were seen again at 4 months for an angiogram then at 6 months for a Doppler examination. One patient needed complete redilatation with a stent and one other required dilatation of the stent.

CONCLUSIONS

Endoluminal angioplasty of the carotid arteries gave encouraging results in this high-risk population (underlying disease, age, bilateral carotid lesions, arterial coronary grafts). This technique should be used more widely for patients with severe multiple arterial lesions.

[Cardiac transplantation. Evaluation of a consecutive series of 75 grafts]

OBJECTIVES

The global results of various series of heart transplantation (HT) are essential to assess the life expectancy provided by this technique. Due to the increasing graft shortage, it appears essential to very strictly candidates for HT.

METHODS

From March 8, 1989 to December 7, 1994, 75 orthotopic Hts were performed in 62 men and 12 women (1 case of retransplantation). The mean age was 47.46 +/- 15.02 years (range: 2.5-66 years). Four patients were younger than 10 years and 22 were older than 60 years. Our series included more cases of ischaemic heart disease (36) than dilated cardiomyopathies (33), with a history of cardiac surgery in almost one quarter (20) of patients with ischaemic heart disease.

RESULTS

The immediate postoperative survival rate was 94.7% with 3 deaths attributable to refractory pulmonary hypertension associated with graft failure and one death related to postoperative tamponade. Five other patients died during the following 3 months, increasing the mean global survival to 88%. After a mean follow-up of 2.1 years (maximum 5.8 years), the actuarial 5-year survival rate was 56.8%. Eleven patients died between 4 and 38 months (mean: 18.2 months). Two deaths were due to cancers, 4 were due to septicaemia, another 4 were due to rejection and finally 1 was due to meningeal haemorrhage. The frequency (19) of reoperations for clot removal was due to the large number of patients with a history of previous heart surgery (20).

CONCLUSION

Strict recipient selection, possibly based on 123I-MIBG scintigraphy, the use of pulsatile circulatory assistance systems, improved CMV, morphometry and donor-recipient age matching, should optimize the results of a technique, whose efficacy is confirmed in this series.

[Indications and role of albumin for vascular loading in the operating room]

Prospective clinical studies on albumin and non human colloids, administered peroperatively, were analysed. Only those with a level of evidence I or II were considered. On the basis of the cost-effectiveness ratio, albumin should not be the first choice treatment for peroperative plasma volume expansion. Low molecular weight hydroxyethylstarch is as efficient for restoration and maintenance of volaemia and colloid osmotic pressure. Albumin is administered when other colloids are contra-indicated or when their upper limit of volume has been reached.

Radioimmunoassay for plasma histamine: a study of false positive and false negative values

In order to achieve a correct diagnosis of drug anaphylaxis using a radioimmunoassay devoid of interferences, we have studied factors leading to false positive or false negative values of plasma histamine. Different steps in sample collection were studied systematically in 30 normal volunteers. False positive values were found in haemolysed samples, with histamine concentrations being correlated with haemoglobin concentrations, and where plasma was aspirated from the white-cell layer. There was no significant increase when a tourniquet or vacuum tubes were used, or when blood tubes were left at 4 degrees C overnight. In 12 patients who experienced an anaphylactic reaction, histamine disappeared from blood 10 times more slowly than expected. False negative values were found in two pregnant women and one heparinized patient. Histamine was remarkably stable in vitro in blood or plasma samples, whereas it disappeared rapidly when plasma from a pregnant woman or a heparinized patient was added to the sample. We conclude that false positive and false negative values are rare when using this radioimmunoassay.

EARLY DIAGNOSIS OF ANAPHYLACTIC REACTIONS TO NEUROMUSCULAR BLOCKING DRUGS

Neuromuscular blocking drugs (NMB) are involved in most of the anaphylactic reactions occurring during anaesthesia. Patients are evaluated usually 6 weeks after the reaction, by skin testing. In order to obtain an earlier diagnosis, we have measured plasma concentrations of histamine, tryptase and NMB-specific IgE antibodies in 14 patients after an anaphylactoid reaction. We have compared the results with those of skin tests and specific IgE obtained 8 weeks later. Good agreement was observed in all subjects between the results of skin tests and the values for histamine and tryptase, provided that both markers were measured simultaneously. Furthermore, there was no significant difference between the concentrations of NMB-specific IgE antibodies observed at the time of the reaction and 8 weeks later. Thus anaphylaxis to neuromuscular blocking drugs can be demonstrated at the time of the reaction by measuring plasma concentrations of histamine, tryptase and specific IgE. In the event of the patient's death, such measurements may be useful in identifying the likely cause.

[Early biological markers of anaphylactoid reactions occurring during anesthesia]

Three markers of in vivo histamine release, i.e. plasma histamine and tryptase, and urinary methylhistamine, were assessed using sensitive radioimmunoassays in 18 patients who had experienced an adverse reaction to an anaesthetic agent. Controls were obtained from 35 patients following a general anaesthetic, which included a muscle relaxant, and who remained free from any adverse reaction. A first blood sample was obtained from all 18 patients a mean 25 +/- 26 min after the reaction, and a second one in thirteen a mean 120 +/- 65 min after the reaction. Ten patients had had a life-threatening reaction. Plasma histamine levels were increased in all these cases, and tryptase concentrations in 9 out of 10. Urinary methylhistamine rarely reached pathological levels (4 out of 10). Skin tests were positive in the four tested patients. Plasma histamine concentration was still high in 8 cases thirty minutes after the reaction, and remained increased for more than 2 h in two patients. Among the other eight patients with a moderate reaction, 3 had high histamine levels, with normal or weakly increased tryptase concentrations, and normal urinary methylhistamine. Two of these patients had positive skin tests. There were no abnormal findings in any of the investigations carried out in the other five patients, except for a slightly positive skin test to atracurium in one patient. Plasma histamine had a higher sensitivity than tryptase levels. Methylhistamine concentrations were only rarely of interest. There were no false positives with the three investigated markers.(ABSTRACT TRUNCATED AT 250 WORDS)

[Efficacy and tolerance of Elohes 6% during peroperative normovolemic dilution]

This study assessed the cardiovascular stability of intraoperative normovolaemic haemodilution carried out with 6% Elohes during the exchange, the intraoperative, recovery and postoperative periods, as well as its effects on coagulation and renal function. Ten patients, ranked ASA 1, were included. Patients were premedicated with 100 mg of hydroxyzine, and anaesthesia was induced with 2 mg.kg-1 propofol, 3 micrograms.kg-1 fentanyl, and 0.5 mg.kg-1 atracurium. Maintenance was obtained with propofol, fentanyl and 50% nitrous oxide in oxygen. Haemodilution, carried out with a peripheral venous catheter, size 14 G, consisted in the removal of 15 ml.kg-1 of blood and its simultaneous replacement with Elohes 6%. Heart rate, systolic, diastolic and mean blood pressures were recorded before anaesthetic induction, every 5 min during the haemodilution, and thereafter during surgery, recovery and postoperative periods, up to the third postoperative day. Blood haemoglobin, fibrinogen, prothrombin, sodium, potassium, urea and creatinine concentrations, haematocrit, platelet count, and bleeding and activated cephalin times were assessed before and immediately after haemodilution, and on postoperative days 1 and 3. A mean of 1,295 +/- 68 ml of blood were removed during a 32 +/- 2 min period, and replaced by 1,315 +/- 64 ml of Elohes. Haematocrit decreased from 44 +/- 1.1% to 29.7 +/- 0.8%. There were no significant alterations in other parameters, except for an increase in heart rate at the time of extubation. Cardiovascular parameters, as well as the haemodilution, were stable up to the end of the study period. It is concluded that replacing blood with Elohes for intentional haemodilution affords convenient cardiovascular stability.(ABSTRACT TRUNCATED AT 250 WORDS)

Compared peripheral vascular responses to intravenous and intra-arterial administrations of positive inotropic agents in conscious dogs

In addition to their direct effects on cardiac contractility, a number of positive inotropic agents also induce, through direct peripheral vasodilation, a reduction in afterload which is of major importance in their beneficial effects in the treatment of congestive heart failure. However, the induced increase in cardiac output can indirectly improve perfusion of peripheral vessels through a flow-mediated mechanism. Thus, the goal of the present study was to compare the direct peripheral vasomotor effects assessed in the iliac vascular bed of four positive inotropic agents: DPI 201-106, ouabain, milrinone and dobutamine, in the presence and absence of simultaneous changes in cardiac function. These drugs were administered either through intravenous or intra-arterial (aorto-iliac catheter) routes in 6 conscious dogs, chronically instrumented for the measurement of heart rate, arterial pressure, left ventricular dP/dt, iliac artery blood flow and iliac artery diameter (sonomicrometry). Intravenous doses were selected as those inducing equipotent positive inotropic responses whereas intra-arterial doses were below those required to induce any significant change in systemic hemodynamics. Ouabain decreased and milrinone increased both iliac blood flow and diameter after either intravenous or intra-arterial administrations. In contrast, iliac blood flow did not change after intra-arterial administration of DPI 201-106 and dobutamine whereas iliac diameter was not modified by DPI 201-106 and even decreased with dobutamine. After intravenous administration, DPI 201-106 but not dobutamine, increased both iliac blood flow and diameter. Thus, this experimental preparation can differentiate inotropic agents with direct vasodilating (milrinone) or constricting (ouabain) properties and those (DPI 201-106 and dobutamine) with indirect vasodilating effects most likely mediated by the improvement in cardiac function.

Hemodynamic and cardiac effects of spiraprilat in normal and sodium depleted conscious dogs

The cardiac and hemodynamic effects of 3 doses (0.1, 0.3 and 1 mg/kg, iv) of spiraprilat, the diacid active metabolite of the new angiotensin I converting enzyme inhibitor spirapril, have been investigated and compared to those of saline in chronically implanted conscious dogs at rest. Under a normal sodium diet, spiraprilat, 1 mg/kg, induced significant (at least P less than 0.05) decreases in mean arterial pressure (MAP, -11%), total peripheral resistance (TPR, -21%), left ventricular end diastolic pressure (LVEDP, -15%) and increases in heart rate (HR, +12%) and cardiac output (CO, +16%) whereas dP/dtmax remained unchanged. Spiraprilat-induced tachycardia was not modified by propranolol pre-treatment but was abolished by previous administration of the propranolol-N-methylatropine combination. Spiraprilat, 0.1 mg/kg, did not affect any parameter, but spiraprilat, 0.3 mg/kg, showed intermediate effects. Finally, sodium depletion strongly potentiated spiraprilat effects on MAP, TPR, LVEDP, HR and CO. We conclude that: a), in conscious dogs under normal sodium diet, spiraprilat reduces TPR and MAP through peripheral vasodilating properties; b), spiraprilat-induced tachycardia is mainly related to parasympathetic tone withdrawal, possibly in relation with high and low pressure baroreceptors deactivation; and c), sodium depletion considerably potentiates spiraprilat cardiac and hemodynamic effects.

Cardiac and hemodynamic effects of S(-)- and (R(+)-DPI 201-106 and of racemic DPI 201-106 in conscious dogs

The cardiac and hemodynamic effects of (+/-)-DPI 201-106 (0.6 mg/kg), S(-)-DPI (0.3 mg/kg), R(+)-DPI (0.3 mg/kg), and their vehicle were compared in chronically implanted conscious dogs. (+/-)-DPI and S(-)-DPI induced qualitatively and quantitatively similar effects, increasing LV dP/dt, cardiac output and stroke volume and reducing total peripheral resistance. In contrast, R(+)-DPI decreased only stroke volume. It is concluded that (a) the positive inotropic effects of (+/-)-DPI in vivo are caused by its S(-) enantiomer, and (b) the peripheral vasodilating effects of (+/-)-DPI may not be linked to the drug's calcium antagonist properties.

[Pharmacokinetics and pharmacodynamic effects of digoxin in dilated cardiomyopathies. Influence of nicardipine]

Numerous studies have been devoted to the effect of slow calcium channel inhibitors on plasma digoxin concentrations. The principal drugs tested, verapamil and nifedipine, were found to increase significantly plasma digoxin levels mainly by reducing digoxin total clearance. Very few studies on the nicardipine-digoxin interaction have been reported. The dual purpose of the present study was to evaluate the influence of orally administered nicardipine on plasma digoxin concentrations over 24 hours and to measure possible variations in the pharmacodynamic effects of digoxin in 9 patients with chronic congestive heart failure. The pharmacodynamic assessment involved simple and cross-sectional echocardiography, systolic time interval measurements and cardiac catheterization. In these patients under chronic digoxin treatment, oral nicardipine had little effect on plasma digoxin concentrations which increased but not significantly; no sign of digitalis toxicity was observed. Nicardipine improved left ventricular function and myocardial contractility by reducing after-load, the nicardipine-induced peripheral vasodilatation tending to counteract the digoxin-induced vasoconstriction.

[Antibiotic prophylaxis in cardiac surgery: 12-hour cefazolin versus 36-hour cefazolin]

A prospective randomized study was carried out to assess two protocols of antibiotic prophylaxis in patients undergoing cardiac surgery with cardiopulmonary by-pass. Each patient of the first group received four intravenous injections of 1 g cefazolin over a period of 12 h, whilst in the second group each one received twelve doses over a period of 36 h. Between May 1983 and April 1984, 159 patients scheduled for cardiac surgery entered the study. Those who underwent emergency surgery, or weighed less than 20 kg, or received antibiotics in the week before surgery, or had a previous history of anaphylaxis to cephalosporins were not included in the study. Both groups were similar in their distribution of age, weight, height, sex, past history of infectious disease, surgery and iatrogenic factors. There were no significant differences between the two groups in the number of minor infections and bacterial floral changes. There were no major infections either (septicaemia, mediastinitis, endocarditis). Temperature charts were the same on the first four days. The length of stay at hospital was the same in both groups. Since the efficacy of the two protocols in preventing major infections was the same, the authors recommend the short prophylaxis with cephazolin for cardiac surgery patients.

[Preventive antibiotics in cardiac surgery: cefazolin versus cefamandole]

A prospective, randomized study was carried out to evaluate two antibiotic prophylactic regimens for patients undergoing cardiac surgery with cardiopulmonary bypass. Each patient of the first group (cefazolin) received four intravenous injections of 1 g cefazolin during 12 hours, patients of second (cefamandole), four doses of 750 mg. 155 patients scheduled for cardiac operation were included in the study. (May 1983 to April 1984). Patients were not admitted to the study in case of emergency, if their weight was less than 20 kg, if they had received antibiotics during the week before surgery or if they had a history of anaphylactic reactions to cephalosporins. There were no differences between the two groups on age, weight, height, sex, previous history of infectious disease, surgery and intensive care. There were no significant differences between the two groups in minor infections. The rate of urinary tract infection by streptococci was significatively higher (p less than 0.02) in the cefamandole group (38.3%) than in the cefazolin group (17.6%). There were no major infections (septicemia, mediastinitis, endocarditis). Patients temperature was the same during the first four postoperative days. Hospital stay was the similar in the two groups. The two antibiotics are similarly effective to prevent major infections in cardiac surgery. However cefazolin was preferred for antibiotic prophylaxis in cardiac surgery because of the higher rate of streptococcal urinary infections in patients given cefamandole.

[Thromboses of the right cardiac cavities: echocardiographic diagnosis and therapeutic indications apropos of 2 cases and review of the literature]

Two cases of pulmonary emboli are reported: a thrombus was detected by echocardiography in the right atrium in the first case and in the right ventricle in the second. Following a review of the 28 cases published to date, criteria are given for distinguishing between those thrombi embolizing from the peripheral veins and those arising in the right cavities of the heart. Therapeutic recommendations are also given.