Accelerated idioventricular rhythm during spinal anesthesia for cesarean section.

During cesarean section under regional anesthesia various anomalies of the electrocardiogram are reported such as bradycardia, supraventricular and ventricular premature beats, supraventricular paroxysmal tachicardia, S-T depression non-significant for myocardial ischemia and second degree atrioventricular block. We describe two cases of accelerated idioventricular rhythm in patients undergoing elective cesarean section with spinal anesthesia of which we have not found mention in the literature. This arrhythmia is not dangerous and does not usually evolve into ventricular fibrillation. During spinal anesthesia, however, it can exacerbate hypotension and, if misdiagnosed, a further administration of ephedrine can increase the duration of accelerated idioventricular rhythm. When necessary, for example in symptomatic hypotension or severe bradycardia, atropine is advised in order to inhibit vagal tone and increase the activity of the sino-atrial node, obtaining a pharmacological overdrive. This therapy is appropriate even if the frequency of the accelerated idioventricular rhythm is high.

Effect of fentanyl-oxygen anesthesia during cardiac surgery on serum thyroid hormones.

Twenty-five euthyroid patients who underwent cardiac surgery with fentanyl-oxygen anesthesia were studied. The authors confirm that some thyroid hormones undoubtedly take part in a non-specific pool of reactions caused by surgical stress. For one or more days, all the patients had total triiodothyronine (TT3) and free triiodothyronine (FT3) levels clearly below the normal values, with a parallel increase in reverse triiodothyronine (rT3, biologically inactive). Changes in total (TT4) and free thyroxine (FT4), although significant, were smaller and hard to interpret. The most important changes occurred on the first postoperative day. Of seven patients who before the operation had a TT3 value below the lower normal limit, six had at discharge a mean TT3 level significantly above it. Serum TT3 concentrations could be a reliable prognostic index. High-dose fentanyl anesthesia probably does not affect thyroid hormone response to surgical stress. To date, the mechanisms which cause reduction of serum triiodothyronine have not been fully discovered and it is not known for certain whether this reduction is beneficial to the human organism.

Blood transfusion during cesarean section. A 12 years' retrospective analysis.

Transfusional practice over the last 12 years was investigated retrospectively in 1618 women submitted to lower-segment cesarean section. The overall percentage of transfused patients was low (2.4%) and it has become lower in the last four years (1.1%), in concomitance with the development of better knowledge of tissue oxygenation and with the fear of transmitting infectious diseases, factors which have led anesthesiologists to employ blood only when strictly required. Three conditions greatly increased the risk of bleeding: placenta previa, abruptio placentae and coagulation disorders. Previous cesarean section, fetal distress, dystocias and hypertensive disorders of pregnancy did not increase the risk of bleeding and no difference was found between elective and non-elective surgery. Since for elective surgery two units of blood were crossmatched, the crossmatched/transfused ratio (C/T ratio) was very high (60.8/1). To improve blood bank service efficiency, for surgical operations like cesarean section which rarely require blood, it is possible simply to recur to a type and screen (TS) procedure instead of crossmatching blood, but for categories of patients identified as being at high risk of bleeding--placenta previa, abruptio placentae, coagulation disorders--it is advisable to have crossmatched blood available in the operating theatre.

Fibrinolytic (rt-PA) therapy for superior vena cava thrombosis in a multiple trauma patient.

An adult multiple trauma patient (head injury with coma, blunt chest trauma, bone and pelvis fractures) developed superior vena cava thrombosis which extended to the right atrium as a complication of central venous catheterism. Since a four day heparin therapy was unsuccessful, the patient was treated with recombinant tissue-type plasminogen activator (rt-PA), 100 mg over three hours. Thrombolysis with rt-PA was not associated with cutaneous or internal bleeding and was partially effective (improvement of the clinical picture, disappearance of the right atrium thrombus, superior vena cava still occluded). Although our patient could have benefited from an additional administration of rt-PA, we did not start a second course because the risk of major hemorrhage increases over 100 mg. For its relative clot-selectivity rt-PA could be indicated when fibrinolytic treatment is required in multiple trauma patient, but safe and more efficacious regimens have still to be defined.

Behaviour of urinary D-glucaric acid excretion in surgical patients and anaesthesiology staff acutely exposed to isoflurane and nitrous oxide.

Liver function abnormalities have been observed in humans exposed to anaesthetics inhalation. Furthermore, experimental studies have revealed changes in microsomal enzyme activity caused by inhalation of a variety of anaesthetics. The study was designed to assess liver microsomal enzyme function by means of a simple non-invasive test, i.e., measurement of urinary D-glucaric acid (UDGA) excretion. Three groups of selected subjects were examined: (i) 20 patients undergoing orthopaedic surgery receiving an anesthetic mixture, (ii) 18 workers of an Anesthesiology and Intensive Care Unit, occupationally exposed to anesthetics, (iii) 16 controls. Both in the patients and anesthesiology staff, the post-operative UDGA mean values were significantly increased compared to the pre-operative values. The study shows that the behaviour of UDGA excretion is similar in patients and in anaesthesiology staff. Although it is not possible to clarify the mechanism involved, this finding is regarded as a response of the liver to anaesthetics administration in patients and to both environmental pollution and occupational stress in hospital staff.

Thyroxine pretreatment and halothane administration alter Ca2+ transport and transmembrane potential in rat liver mitochondria. An additional mechanism for halothane-induced liver damage in the hyperthyroid rat model.

Male rats pretreated with thyroid hormones and exposed to halothane in non-hypoxic conditions develop acute liver damage. In order to investigate the mechanisms leading to liver damage in this animal model, the effects of thyroxine (T4) pretreatment and halothane administration on Ca2+ transport and transmembrane potential were studied in isolated rat liver mitochondria. Five-day T4-pretreatment reduced the mitochondrial Ca2+ loading capacity and increased the rate of Ca2+ cycling across the mitochondrial membrane. Halothane administration further increased Ca2+ cycling and produced a time- and dose-dependent loss of transmembrane potential which was more pronounced in mitochondria from T4-pretreated rats than in euthyroid animals. When mitochondria from T4-pretreated rats were incubated in the presence of the Ca2+ chelator EGTA, membrane potential was well preserved. In contrast, when Ca2+ concentration in the extramitochondrial medium was increased, mitochondria deenergization occurred earlier. These findings confirm that alterations in Ca2+ transport and mitochondrial function can be interrelated events and suggest that a Ca(2+)-dependent, halothane-induced loss of transmembrane potential could participate in generating acute liver damage in hyperthyroid rats exposed to halothane in non-hypoxic conditions.

Low flow anaesthesia reduces occupational exposure to inhalation anaesthetics. Environmental and biological measurements in operating room personnel.

In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow > or = minute volume) and low flow (LF) (fresh gas flow = 1.5 l/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting branch of the ventilator on environmental and urinary concentrations of inhalation anaesthetics were also investigated. The study was carried out in the same operating room provided with non-recirculating air changes (10 per hour). It involved anaesthetists and nurses during routine activity. N2O and isoflurane concentrations (time-weighted average) were measured after 3-hour continuous exposure: 1) in the environment at the level of the personnel's breathing zone (Ci); 2) in the environment at the ventilator zone (C); 3) in urine (Cu). During OC anaesthesia without active scavenging the breathing zone concentration of both N2O and isoflurane was very high (194.6 +/- 15.2 and 5.0 +/- 0.4 ppm, respectively). The activation of the scavenging greatly reduced the breathing zone concentration of N2O (31.6 +/- 4.1 ppm) and isoflurane (1.7 +/- 0.2 ppm). LF anaesthesia (with active scavenging) significantly reduced the environmental concentration of both anaesthetics (Ci N2O and isoflurane 22.7 +/- 1.8 and 0.6 +/- 0.04 ppm, respectively). During LF anaesthesia the breathing zone concentration of N2O remained low, even without scavenging (22.7 +/- 1.8 ppm). Similar results were obtained by measuring N2O and isoflurane concentrations at the ventilator zone and in urine.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of chest injuries in intensive care. Critical review of 54 clinical cases]. / Il trattamento del trauma toracico in rianimazione. Revisione critica di 54 casi clinici.

All 54 chest trauma patients admitted to Resuscitation II of Pavia's S. Matteo Polyclinic in the period 1974-1979 have been reviewed in a critical analysis. Particular attention was paid to mortality in relation to age, associated pathology, treatment and the complications arising during the course of the trauma. Resuscitation Centres are identified as the ideal places for treating these patients. Cranio-encephalic and superimposed abdominal lesions are the main factors pointing to an unfavourable prognosis, and protection against infectious complications is the key to therapy.

[D-glucaric acid. A new method proposed to investigate damage from exposure to anesthetic gas and vapors]. / Acido D-Glucarico. Una nuova metodologia proposta per indagare il danno da esposizione a gas e vapori anestetici.

Acute exposure and hepatotoxicity following full anesthetic doses is controversial, despite various experimental trials. On the other hand, microsomial enzyme induction following the chronic use of anesthetic gases and vapours, even with minimal metabolism, has been established. Therefore, there is increasing interest in the field of prevention to develop techniques and instruments to minimize pollution of anesthetic vapours and screening methods to detect early liver-damage. We have evaluated the reliability of D-Glucaric Acid test in monitoring microsomial enzyme induction after anesthesia. We evaluated urinary excretion of D-Glucaric Acid before and after exposure to anesthetic gases in 53 subjects, including medical personnel and patients. Statistical analysis of these data confirm the usefulness of this technique to assess acute liver damage in patients undergoing general anesthesia (postoperative increase of 10.5 microns/l as average value of urinary acid excretion, chi 2 = 9.8; p less than 0.01). This technique is also valuable in demonstrating damage in operating room personnel due to chronic exposure (base values greater than 12 microns/l in anesthesiologists with a 9 microns/l increase at the end of surgical intervention, chi 2 = 8.1; p less than 0.01). Data of patients submitted to local anesthesia are more difficult to interprete. They presented a decrease in acid urinary excretion (less than 10 microns/l; chi 2 = 1.93; p less than 0.2) probably due to hemodynamic changes which occurred during spinal block or due to degree of sedation related to de-afferentation itself.

The effects of thyroid hormone modulation on rat liver injury associated with ischemia-reperfusion and cold storage.

UNLABELLED: We investigated the effects of thyroid hormone modulation on liver injury associated with ischemia-reperfusion (I-R) and cold storage in rats. First, euthyroid and thyroxine (T4)-pretreated rats were exposed in vivo to 20-min global liver ischemia, then 30-min reperfusion. Liver injury was assessed by measuring serum alanine aminotransferase (ALT) levels. Liver concentrations of adenine nucleotides, reduced glutathione (GSH), and oxidized glutathione were evaluated. Second, rats were given the antithyroid drug propylthiouracil (PTU). Livers stored at 0-1 degrees C in Euro-Collins' solution for 20 h were reperfused at 37 degrees C for 15 min. Lactate dehydrogenase (LDH) in the effluent perfusate and bile flow were evaluated during reperfusion. Serum ALT levels increased after ischemia and I-R. ALT increased significantly more in T4-pretreated than in euthyroid rats after ischemia and I-R. Preischemic levels of adenosine triphosphate (ATP) were significantly lower in livers from T4-pretreated than in euthyroid rats (6.22 +/- 0.7 and 11 +/- 0.9 nmol/mg protein, respectively; P < 0.05). After ischemia, liver ATP was similarly reduced in T4-pretreated and euthyroid rats. After reperfusion, ATP partially recovered in euthyroid rats but remained low in T4-pretreated rats (6.7 +/- 1.0 and 1.91 +/- 0.7 nmol/mg protein, respectively; P < 0.05). Preischemic levels of liver GSH decreased to 44% in T4-pretreated rats. After ischemia, GSH decreased similarly in euthyroid and T4-pretreated rats. GSH recovered promptly after reperfusion in euthyroid rats but remained low in T4-pretreated rats (13.9 +/- 3.3 and 3.9 +/- 0.9 nmol/mg protein, respectively; P < 0.02). During reperfusion after cold storage, LDH in effluent perfusate was significantly lower and bile flow higher in livers from PTU-pretreated rats than from euthyroid rats. The histopathological changes observed after I-R and cold storage confirmed the biochemical findings. Our results suggest that T4 administration exacerbates pretransplant liver damage by increasing liver susceptibility to I-R, whereas PTU administration reduces the liver injury associated with cold storage. IMPLICATIONS: We studied the effects of thyroid hormone modulation on liver injury associated with ischemia-reperfusion and cold storage in rats. Thyroxine administration increased susceptibility to ischemia-reperfusion injury, whereas the antithyroid agent propylthiouracil reduced the deleterious effects associated with cold storage.