Glide video laryngoscope for the management of foreign bodies impacted at the hypopharyngeal level in adults

BACKGROUND

Cricopharyngeal foreign bodies (FBs) impaction in adults is a common clinical problem; without treatment, the sequelae may be lethal due to local and/or mediastinal infection. When direct laryngoscopy and flexible fiberoptic endoscopy are ineffective, rigid endoscopy is the method of choice requiring general anesthesia. The new video laryngoscopes represent a great advancement in the assessment of the laryngeal inlet. Aim of the study was to assess the feasibility of identifying and removing FBs impacted at crycofaringeal and upper oesophageal sphincter by the video laryngoscope.

METHODS

In a period of 30 months, on an urgent basis, we systematically assessed by GlideScope® video laryngoscope all adult patients with a diagnosis of impacted crycofaringeal upper esophageal FB, after unsuccessful removal attempts in the otolaryngology or gastroenterology unit.

RESULTS

Twenty-six consecutive patients were evaluated. In conscious sedation by video laryngoscope 17 FBs were identified and removed from the hypopharynx or upper esophageal sphincter. In 9 patients rigid endoscopy in general anesthesia and tracheal intubation was necessary to remove FBs impacted beyond the upper esophageal sphincter.

CONCLUSION

In our experience video laryngoscope, because of the magnified vision, the better patient comfort and no requirement of general anesthesia, represents a great improvement in identifying and removing in conscious sedation even small and thin foreign bodies not recognized by radiological and otolaryngology examination and not readily detected by direct endoscopy.

The Helsinki Declaration on Patient Safety in Anesthesiology: a way forward with the European Board and the European Society of Anesthesiology

Anesthesiology, which includes anaesthesia, perioperative care, intensive care medicine, emergency medicine and pain therapy, is acknowledged as the leading medical specialty in addressing issues of patient safety, but there is still a long way to go. Several factors pose hazards in Anesthesiology, like increasingly older and sicker patients, more complex surgical interventions, more pressure on throughput, as well as new drugs and devices. To better design educational and research strategies to improve patient safety, the European Board of Anesthesiology (EBA) and the European Society of Anesthesiology (ESA) have produced a blueprint for patient safety in Anesthesiology. This document, to be known as the Helsinki Declaration on Patient Safety in Anesthesiology, was endorsed together with the World Health Organization (WHO), the World Federation of Societies of Anesthesiologists (WFSA), and the European Patients' Federation (EPF) at the Euroanaesthesia meeting in Helsinki in June 2010. It was signed by several Presidents of National Anesthesiology Societies as well as other stakeholders. The Helsinki Declaration on Patient Safety in Anesthesiology represents a shared European view of what is necessary to improve patient safety, recommending practical steps that all anesthesiologists can include in their own clinical practice. The Italian Society of Anaesthesia, Analgesia, Reanimation and Intensive Care (SIAARTI) is looking forward to continuing work on "patient safety" issues in Europe, and to cooperating with the ESA in the best interest of European patients.

Maternal and neonatal outcome after cesarean section: the impact of anesthesia

BACKGROUND

Among the anesthetic technologies used, regional anesthesia is becoming the most common in cesarean section (CS) deliveries. Aim. This retrospective survey examined the variables taken into account when selecting the anesthetic technique to be used, and how this choice affects the outcome for the mother and the newborn.

METHODS

One thousand eight hundred and seventy elective and emergency CS were evaluated for anesthetic technique used, indications, and maternal and neonatal outcome.

RESULTS

Of the 611 elective CS (32.6%), 206 (33.8%) were performed under general anesthesia and 405 (66.2%) under regional anesthesia. Of the 1259 emergency CS performed (67.4%), 525 (41.9%) were under general anesthesia and 734 (58.1%) under regional anesthesia. Conditions associated with a newborn 1-minute Apgar score of <7 were general anesthesia and multiple pregnancy (p<0.01); a 5-minute Apgar score of <7 was only associated with multiple pregnancy. The most important factor for very low Apgar scores was the presence of fetal malformations. Whatever the chosen technique, neither maternal deaths directly or indirectly due to the anesthesia nor major maternal and perinatal complications were found.

CONCLUSIONS

This survey confirms the preference for regional anesthesia during elective cesarean sections and for general anesthesia in emergency situations. Moreover, newborn outcome was found not to be influenced either by the technique used or by the character of the procedure.

A multicenter survey on anaesthesia practice in Italy

AIM

To achieve more information on anaesthesia practice in Italy.

METHODS

One questionnaire was completed for every anaesthetic procedure performed during the last week of June 1999 in 162 public hospitals selected in the northern, central and southern parts of Italy.

RESULTS

A total of 12 263 anaesthetic procedures were performed during the study week in participating hospitals, extrapolating to 4 905200 anaesthetic procedures performed in Italy in 1999 (95% confidence interval, (+/-245000), with an annual rate of 8.5 anaesthetic procedures per 100 population. Children represented 12%, adults 60%, and elderly patients 28% of all studied patients. Emergency procedures were performed in 14% of cases; only 14% of cases were outpatients, but 31% of patients were discharged within 48 h after surgery. General anaesthesia was used in 65% of cases (45% volatile and 20% intravenous anaesthesia), regional anaesthesia in 24%, local anaesthesia in 8.8% and monitored anaesthesia care in 2.2%. No differences in the distribution of anaesthesia techniques were observed according to the geographic region or hospital size.

CONCLUSION

Some organizational problems still remain to be implemented, including the development of proper preoperative evaluation clinics and postanaesthesia care units, especially in bigger hospitals with more than 1 000 beds.

A prospective, randomized, double-blind comparison of epidural levobupivacaine 0.5% with epidural ropivacaine 0.75% for lower limb procedures

BACKGROUND AND OBJECTIVE

This prospective, randomized, observer-blinded study compared onset time and duration of epidural anaesthesia produced by with levobupivacaine and ropivacaine for lower limb surgery.

METHODS

ASA I-III adult patients undergoing elective lower limb procedures were randomized to receive epidural levobupivacaine 0.5% 15 mL (n = 30) or epidural ropivacaine 0.75% 15 mL (n = 35). A blinded observer evaluated onset time and regression of motor and sensory block, and intraoperative needs for fentanyl supplementation (0.1 mg intravenously).

RESULTS

With levobupivacaine, onset time was 29 +/- 24 min, with ropivacaine it was 25 +/- 22 min (P = 0.41). Complete resolution of motor block required 105 +/- 63 min with levobupivacaine and 95 +/- 48 min with ropivacaine (P = 0.86). The time for regression of sensory block to T12 was 185 +/- 77 min with levobupivacaine and 201 +/- 75 min with ropivacaine (P = 0.46). Analgesic supplementation was required in one patient receiving levobupivacaine (3.5%) and in two patients receiving ropivacaine (5.7%) (P = 0.99).

CONCLUSIONS

In adults undergoing lower limb surgery, levobupivacaine 0.5% 15 mL produces an epidural block with the same clinical profile as ropivacaine 0.75% 15 mL.

Sevoflurane analgesia in obstetrics: a pilot study

Continuous and intermittent administration of inhalational anesthetics has been successfully employed for treating pain during labor. We conjectured that intermittent sevoflurane administration would be effective for pain relief during labor without side effects to the mother or fetus. Fifty parturients breathed a mixture of 2-3% sevoflurane, oxygen and air before each uterine contraction began. The patients assessed the quality of analgesia by using a visual analogue scale (0-10) before the administration of sevoflurane and after each uterine contraction. All parturients but one were satisfied, demonstrating a mean visual analogue score before and after sevoflurane administration of 8.7 +/- 1.1 and 3.3 +/- 1.5, respectively. Apgar scores at 1 and 5 min were 9 (range 5-9) and 10 (range 8-10), respectively. Our findings suggest that sevoflurane could be effective for the treatment of labor pain.

[The mandrake root and the Viennese Dioscorides]

Pedanius Dioscorides of Anazarba in Cilicia lived in the first century. He was a Greek physician who served as a surgeon in Neròs army. He wrote several books on materia medica. One of his manuscripts with drawings of medicinal herbs was copied down in the fifth century. In this book on Greek Herbal, still kept in the National Library of Vienna, Dioscorides gave a detailed description of mandragora (mandrake). Over the ages, the mandrake has been endowed with a wonderful and mystical aura. Examples are superstitions regarding harvesting of the plant. While being torn from the ground, the mandrake would emit a horrible shriek, that would be fatal to the harvester who hears it. So, if someone simply pulled the plant, they would either die or go mad. To avoid that fate, the plant could be partially dug with a few remaining roots staying in the ground. Then a starved black dog was tied to the mandrake with a rope. The harvester, with plugged ears, would throw some scraps to the hungry dog. When the unsospecting animal lunged for food, the mandrake would be completely unrooted and the ensuing shriek would kill the dog and spare the man. According to different legends quoted by Theophrastus and Pliny the Elder, other dire consequences of unrooting a mandrake could be avoided by making circles around the plant on the ground with a sword and then facing west while digging. If there were a true Anaesthetic of Antiquity it would have been mandragora. Dioscorides describes how the wine made from mandragora produces anaesthesia: Using a cyathus of it on those who cannot sleep, or are grievously pained, or are being cut, or cauterized they will not feel pain. Here Dioscorides used for the first time the word anaesthesia as absence of sensation as we mean it today.

Sevoflurane provides better recovery than propofol plus fentanyl in anaesthesia for day-care surgery

To compare ease of maintenance and recovery characteristics of sevoflurane and propofol plus fentanyl in day-care anaesthesia, 60 outpatients undergoing elective surgery of up to 3 h duration were randomized to receive sevoflurane or propofol as their primary anaesthetic. Induction was always carried out with propofol, but a fentanyl bolus 5 microg kg-1 was added in the propofol group. Anaesthesia was supplemented with up to 70% N2O. Significantly shorter times to extubation (10.03 min +/- 3.2 SD vs. 17.2 +/- 7.3; P < 0.001) and emergence (10.4 +/- 3.1 vs. 16.8 +/- 6.4; P < 0.001) were observed in the sevoflurane group. Patients treated with sevoflurane felt less confused, showed better performances in the digit symbol substitution test and achieved higher modified Aldrete scores sooner in the post-operative course. Maintenance of anaesthesia with sevoflurane produces faster emergence and recovery than propofol plus fentanyl after anaesthesia of short to intermediate duration.

[Comparison of manual infusion of propofol and target-controlled infusion: effectiveness, safety and acceptability]

BACKGROUND

Diprifusor TCI is a newly developed target-controlled system for the infusion of propofol. Purpose of this study is to evaluate the acceptability, efficacy and safety of Diprifusor TCI in comparison with the manually controlled technique.

METHODS

This multicentre, randomised, parallel group study was carried out in 160 patients undergoing surgical procedures of 10 min to 4 h duration in 8 centres. In each centre 20 male or female patients, aged > or = 18 years, ASA I-III were randomised to treatment with either Diprifusor TCI (TCI group--80 patients) or manually controlled infusion (MI group--80 patients). Assessments included hemodynamics; adverse events, including accidents, actual or possible; recovery times; anesthetist ratings of quality of induction and maintenance, and of ease of control and use of technique. Ratings were summed up in a global quality score (study end-point).

RESULTS

Induction doses were significantly lower (median values 1.4 vs 1.9 mg/kg) and maintenance infusion rate significantly higher (median values 10.2 vs 8.8 mg/kg/h) in the TCI group; anesthetists ratings obtained maximum scores in most patients of either group, but more frequently in the TCI group, with significant differences for ease of control (good 91.2% TCI vs 74.7% IM; adequate 8.8 vs 21.5%; poor 0 vs 3.8%), and of use of technique (good 91.2% TCI vs 60.8% IM; adequate 8.8 vs 39.2%); the global quality score showed a significant advantage for the TCI system (median value 12 vs 11).

CONCLUSIONS

The TCI technique is effective and safe, and has a better acceptability than the manually controlled infusion technique.

A clinical diagnosis of inadvertent epidural administration of potassium chloride

We present a case of accidental epidural administration of potassium chloride, which was diagnosed by clinical signs. The genesis of symptoms and signs following such administration is discussed and compared with other published reports.

Maintenance of and recovery from anaesthesia in elderly patients. A clinical comparison between sevoflurane and isoflurane

BACKGROUND

The goal of this multicenter, prospective, randomized clinical investigation was to compare the clinical efficacy and safety of sevoflurane and isoflurane during the maintenance of and the recovery from general anaesthesia in elderly patients.

METHODS

With the approval of the Ethical Committee and the patient informed consent, 104 ASA physical status II-III patients, aged more than 65 years, were randomized in order to receive either isofluorane (n = 54) or sevoflurane (n = 50) as the main general anaesthetic. After an oral diazepam (0.1-0.2 mg kg-1) and intramuscular atropine (0.007-0.01 mg kg-1) premedication, anaesthesia was induced intravenously and then maintained by adjusting the end-tidal concentrations of the inhalation agent for the maintainance of cardiovascular stability. At the moment of the last skin suture the inhalational agents were discontinued and the neuromuscular block was reversed. The following times were recorded: time of extubation, time of eyes opening, time of command response and readiness for discharge. The occurrence of untoward event throughout the study was also recorded. Before surgery and 24 hr after the procedure, blood was collected in order to assess renal function.

RESULTS

No differences in demography, duration of surgery, exposure to the volatile anaesthetic, and renal function laboratory values were observed between the two groups. The time of extubation (median: 8 min versus 11 min, p < 0.01), emergence (median: 8.5 min versus 12.5 min, p < 0.01), command response (median: 10 min versus 15.5 min, p < 0.01), and suitability for discharge from the recovery area (median: 21 min versus 27.5 min, p < 0.01) were shorter in the sevoflurane group than in the isoflurane one. The success rate (absence of any event) during induction and maintenance periods was better in sevoflurane than isoflurane group (p < 0.02 and p < 0.001, respectively). Hypotension (systolic arterial blood pressure decrease > 30% of baseline values) was observed in 16 patients receiving isoflurane (29%) and only in 5 patients receiving sevoflurane (10%) (p < 0.02).

DISCUSSION

When used in elderly patients undergoing operations of intermediate duration, sevoflurane provides a more rapid emergence from anaesthesia with a faster fulfillment of discharging criteria, and a more stable cardiovascular homeostasis than isoflurane. Renal function also appears to be equally well preserved with both anaesthetics.

Efficacy of propacetamol in the treatment of postoperative pain. Morphine-sparing effect in orthopedic surgery. Italian Collaborative Group on Propacetamol

BACKGROUND

Combined analgesic regimens have been suggested to improve the treatment of postoperative pain. The aim of our study was to evaluate the analgesic efficacy and tolerability of propacetamol, in combination with morphine.

METHODS

Four i.v. infusions of propacetamol 2 g or placebo were administered, in a double-blind fashion, after orthopedic surgery (n = 97). Morphine was administered by a patient-controlled analgesia (PCA) device. The total dose of morphine, pain intensity and global efficacy of treatment were evaluated. Tolerability was assessed by monitoring blood pressure, heart and respiratory rate, sedation scores, adverse events, and renal and hepatic parameters.

RESULTS

The total dose of morphine was significantly decreased in the propacetamol group compared to placebo (9.4 +/- 8.5 mg vs 17.6 +/- 12 mg; P < 0.001), arriving at a sparing effect of 46%. The evolution of pain intensity showed a similar pattern in the two groups. Global efficacy of treatment was rated significantly better by patients receiving the combination propacetamol + PCA morphine (87% of "good"/"excellent" ratings vs 65%; P = 0.01). Tolerability was comparable in the two groups. Eight patients in the propacetamol and 4 patients in the placebo group reported adverse events, of mild/moderate intensity, most commonly nausea/vomiting. Renal and hepatic parameters were also seen to be comparable.

CONCLUSION

These results confirm a significant morphine-sparing effect, significantly better scores in the final assessment by patients, and a good tolerability of propacetamol after orthopedic surgery. The drug may, therefore, represent a useful alternative to NSAIDs, as complementary drug to opioids, in the management of moderate/severe postoperative pain.

[Carbamate and organophosphate poisoning]

Carbamate and organophosphate poisoning is a well known toxicological problem in developing countries, but still has, even in industrialized ones, a high mortality rate and a frequent invalidating outcome. Serious problems especially arise from cardiac (toxic myocarditis, QT prolongation, and other ventricular arrhythmias), muscular (intermediate syndrome, OPIDN), and neuro-behavioral (regressive psychosis, cognitive, mnesic and perceptive alterations) sequelae. Such complications, caused by direct neuronal, cardiac, and muscular damage, sneaky appear immediately after resolution of cholinergic crisis. Early establishment of antidotal (atropine + oximes) and supportive therapy, while reducing duration and seriousness of cholinergic crisis, should increase survival rates. In order to improve "quoad valetudinem" prognosis, widespread use of benzodiazepines is still recommended: such drugs antagonize some central signs and symptoms of cholinergic attack insensitive to atropine (fasciculations, muscular spasms, seizures, anxiety, psychomotor agitation). Moreover, they attenuate neuronal, cardiac, and muscular damage, caused by cholinergic overstimulation, which is responsible for invalidating outcome.

[Ketorolac for prevention of acute postoperative pain]

BACKGROUND

Since NSAIDs are competitive antagonists of cyclooxygenase, they prevent the biosynthesis of prostaglandins, responsible for enhanced nociceptive sensitization and primary hyperalgesia. If NSAIDs administration is performed after eicosanoids cascade activation by surgical trauma, already released prostaglandins can exert their hyperalgesic effects for a finite time. Therefore prophylactic administration of NSAIDs (pre-emptive analgesia) should improve their effectiveness on acute postoperative pain.

AIM OF STUDY

To assess the analgesic effect of preoperatively administered ketorolac, compared with its administration after surgical trauma.

MATERIALS AND METHODS

Thirty adult patients, ASA physical status I-II, undergoing elective septoplasty, were allocated randomly in two groups, depending on timing of i.v. administration of ketorolac 0.4 mg/kg: 10 min before induction (group I); or 5 min after décollement of nasal septum cartilaginoid plan (group II). No other analgesic drugs were given. Postoperative pain was assessed with objective (SAP, DAP, HR) and subjective (VAS, BS 11) methods at 60, 90, 120, 150, and 180 min after the end of surgery. Rate and severity of any side-effect were recorded.

RESULTS

Both VAS and BS 11 showed significant better pain relief after preoperative ketorolac at all time, without any adverse effect. Same result was shown by SAP at 60 and 90 min postoperatively.

CONCLUSIONS

Due to prevention of nociceptive sensitization of prostaglandins released by tissue trauma, prophylactic NSAIDs administration to surgical patients with mild to moderate postoperative pain can improve their antinociceptive effects.

[Sudden infant death syndrome (SIDS): risk conditions and intervention strategies]

The term SIDS describes the unexpected and unexplained death of an apparently well infant. After congenital anomalies, SIDS is the most common cause of infant death in the industrial countries and it is the leading cause of death among infants older than 1 month. Descriptive epidemiological studies have shown a winter excess of cases and a peak of age distribution at about 3 months of age. Although many theories have been proposed to explain the etiology (i.e. fatal toxaemia, autonomic dysfunction, abnormalities of respiratory or cardiovascular control), an underlying cause for SIDS has not been identified. There are, however, a number of factors consistently associated with an elevated risk, the strongest of which are maternal smoking or exposure to substances of abuse during pregnancy, overheating and overinsulation, artificial feeding and prone sleeping position. A fall in the rate of the SIDS can be reasonably expected from changes in these risk factors, from home monitoring of infants suffering a near-SIDS episode and of siblings of SIDS victims, and from parental education programmes.

Pulse oximetry during lumbar epidural anesthesia: reliability of values measured at the hand and the foot

Pulse oximetry is dependent upon the presence of a pulsating vascular bed. The signal detection will be impaired in the presence of vasoconstriction or venous congestion, conditions which may occur readily in clinical practice. We compared the oximetric measurements (SpO2) at the hand and the foot with arterial hemoglobin saturation (SaO2) during lumbar epidural anesthesia. After administration of a crystalloid solution (20 mL/kg body weight lactated Ringer's solution), 40 adult male patients, scheduled for inguinal hernioplasty, received 15 mL of 0.50% plain bupivacaine into the lumbar epidural space. Two pulse oximeter probes were applied to the index finger and toe of the patients, and the SpO2 values were recorded continuously. Arterial hemoglobin saturation (SaO2) was measured using a co-oximeter 5 min before and 30 min after the onset of sensory block. No significant differences were detected between SaO2 (97.7%, SD 0.4%) and SpO2 basal values recorded from the hand (97.8%, SD 0.8%) and the foot (98.1%, SD 0.4%). After the onset of epidural anesthesia, a progressive decrease of SpO2 value recorded from the hand was observed: at 30 min it was 92.3% +/- 1.3% (P < 0.01 compared with baseline). At the same time, the SaO2 value was 97.5% +/- 0.9% (P < 0.01 compared with SpO2 from the hand). On the contrary, no significant difference from both basal value and SaO2 was detected in SpO2 measurements from the toe during the epidural block. In all patients intraoperative decrease of heart rate and arterial blood pressure was < or = 15% from baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

[Removal of a swallowed endotracheal tube in a neonate]

Immediately following delivery a newborn infant was severely depressed. Because no respiratory effort was made and copious mucus was present, a Cole endotracheal tube was easily inserted into the trachea. Because of a mistaken manoeuvre for fastening the tube, the plastic adapter connection became dislodged from the tube, and the tube slipped out of trachea. The physician's gloved fingers could not maintain traction on the tube because of the excessive amount of mucus, and face mask ventilation made easier the slipping into the distal oesophagus. A second endotracheal tube was then properly placed in the trachea and the infant responded. The misplaced tube was removed from the oesophagus using a small, flexible biopsy forceps closed, advanced into the lumen of the swallowed tube under fluoroscopic vision. By opening the forceps, gripping the tube tightly from within, it was easily withdrawn. No adverse effects were observed.

[An anesthetized anesthesiologist tells his experience of waking up accidentally during the operation]

We report the recollections of an anaesthesiologist who experienced urogenital surgery under balanced anaesthesia which was insufficient to prevent awareness during a part of the procedure. The patient was hard apprehensive before surgery and neither sedative nor amnesic drugs were done as premedication. He received an Innovar, thiopentone, suxamethonium, nitrous oxide/oxygen sequence for intubation. Awareness occurred not long after but before administration of isoflurane for maintenance. In that terrifying moments the patient was conscious without pain. According to him the worst aspect of the experience was desperately wanting to move or speak and being unable to do so. In the event of unexpected awareness, the anaesthesiologist must deal with the patient in an honest and forthright manner. Failure to do so lead to dire psychological consequences for the patient and expensive malpractice litigation for the anaesthesiologist.

[Midazolam, propofol, and clonidine for sedation and control of autonomic dysfunction in severe generalized tetanus]

A case of severe tetanus with autonomic dysfunction is reported, describing the adequate response to continuous infusions of both propofol and midazolam, and the successful use of clonidine to control sympathetic over-activity. Tolerance was not observed during the 34 days of propofol and midazolam sedation. Continuously infused clonidine provided good control in combination with sedation and paralysis in this case, and no episodes of cardiovascular derangement were seen, possibly due to the adequate management of filling pressure. Vecuronium was a suitable and manageable muscle relaxant to control skeletal muscle spasms and to facilitate mechanical ventilation.

[Plasma levels of atriopeptin and hemodynamics during major vascular surgery: comparison between isoflurane and propofol+fentanyl]

Atrial natriuretic factor (ANF) is a peptide hormone released from atrial cardiocytes in response to atrial stretch. It has potent and selective effects on vascular smooth muscle, fluid and electrolyte balance, and may interact with other vasoactive substances. The influence of anaesthesia and major vascular surgery on the release and circulation of ANF is unknown. Therefore the relationships between haemodynamic variables, volume expansion and plasma ANF were studied in patients undergoing resection of abdominal aortic aneurysm, randomly assigned to receive isoflurane or propofol+fentanyl anaesthesia. The end point of anaesthetic regimens was the stabilization of mean arterial pressure between +/- 33% from baseline. Haemodynamic parameters and plasma ANF levels were measured preoperatively, after intubation, following aortic cross-clamping, 24 and 48 hours postoperatively. Because of well-known large degree in interpatient pharmacodynamic variability, anaesthesia with propofol and fentanyl did not ensure, usually, the established end point in dose ranges that did not produce unacceptable morbidity. ANF plasma levels were elevated during surgery and in the immediate postoperative period in both groups. A significant correlation was found between ANF levels and mean right atrial pressure. We concluded that anaesthetic drugs do not affect ANF release. Volume expansion for prevention of declamping shock increased, ANF from basal values, during surgery. Inadequacy of postoperative analgesia or persisting atrial stretch could explain the finding of high plasma levels during the immediate postoperative period.

[Systemic poisoning caused by percutaneous absorption of mineral spirit]

Owing to a car accident, the clothes of a injured joiner were permeated with a timber impregnating product containing 51.8% of mineral spirit (a mixture of naphthenes, aromatic and aliphatic hydrocarbons). Despite a short-lasting skin exposure (approximately 40 minutes), dermal contact has caused full thickness burns that, in their turn, have made easier the percutaneous absorption and the storage of organic solvents in subcutaneous tissue depots. Twenty-four hours later, clinical findings of neurologic involvement have arisen, that have got worse when the peripheral tissue perfusion has got better by the adequate replacement of lost blood.

Biochemical and electrophysiologic evidence that propofol enhances GABAergic transmission in the rat brain

The influence of propofol, a new intravenous anesthetic agent, on brain gamma-aminobutyric acid (GABA)-ergic transmission has been investigated both in vitro and in vivo. In vitro, propofol, like benzodiazepines, 1) markedly enhanced 3H-GABA binding in cortical membrane preparations; 2) potentiated muscimol-induced stimulation of 36Cl- uptake in membrane vesicle preparations (the propofol potentiating effect was antagonized by bicuculline); and 3) inhibited 35S-TBPS binding to unwashed membrane preparations from rat cerebral cortex. Finally, propofol failed to displace 3H-flunitrazepam from its binding site, indicating that its site of action in brain is different from that of benzodiazepines. In vivo, the effect of propofol was studied using single-unit recording of the electrical activity of both nondopaminergic neurons in the pars reticulata of the substantia nigra (PR neurons) and of dopaminergic neurons in the pars compacta of the substantia nigra (DA neurons). PR neurons are known to be inhibited by GABA-mimetic drugs and benzodiazepines, whereas DA neurons are tonically inhibited by PR neurons. The intravenous administration of propofol, in a fat emulsion formulation, produced a brief dose-dependent inhibition of the firing rate of PR neurons. The dose producing 50% inhibition of the firing rate was calculated to be 1.2 +/- 0.1 mg/kg. The inhibitory effect lasted less than 5 min. Repeated injections of propofol reproduced the same inhibitory response, whereas continuous infusion (0.5 mg.kg-1.min-1) produced a persistent inhibition of neuronal firing. The inhibitory effect of propofol on PR neurons was potentiated by diazepam and reversed by picrotoxin and bicuculline but was not influenced by the benzodiazepine antagonist Ro 15-1788. These findings suggest that propofol exerts a GABA-mimetic action on PR neurons by acting on a site distinct from the benzodiazepine recognition site. Unlike benzodiazepines, propofol inhibited the firing rate of DA neurons with a potency proportional to its inhibitory effect on PR neurons. The inhibition of DA neurons was reversed by bicuculline and picrotoxin. The results suggest that propofol enhances the inhibitory control over DA neurons by strionigral GABAergic neurons.

[Poisoning caused by chronic exposure to volatile anesthetics. Molecular mechanisms and risk anesthetics]

The possible molecular mechanisms potentially inducing occupational disease among operating room personnel were examined; and the really dangerous anaesthetic agents were identified. As concerns the molecular mechanisms of parenchymatous injury, we surveyed: those connected with free radicals and biological reactive intermediates produced during halothane and nitrous oxide biotransformation; those coming from inorganic fluoride produced during biotransformation of any halogenated anaesthetic agent, and from inorganic bromide released during halothane metabolism; and, finally, those linked to vitamin B12 inactivation from nitrous oxide. Halothane and nitrous oxide can be considered as really dangerous anaesthetic agents for operating room personnel, and enflurane as an agent with marginal toxic power. On the contrary, isoflurane is a safe, useful compound, totally devoided of viscerotoxic effects. From data examined it is possible to conclude that an isoflurane-oxygen-air anaesthesia is safe for operating room personnel more than a balanced anaesthesia with intravenous drugs and nitrous oxide as maintenance.

Bilateral extensive skin necrosis of the lower limbs following prolonged epidural blockade

Skin necrosis has not been described as a complication following epidural sympathetic blockade. We report a case of bilateral extensive skin necrosis of the lower limbs after a 48-hour lumbar epidural blockade in a 71-year-old patient with right hemiplegia and mitral valve regurgitation, without any preoperative clinical evidence of peripheral vascular disease or diabetes, who underwent transurethral prostatectomy.

[Isoflurane pollution in operating rooms]

In three operating rooms of a Sardinian hospital, the Authors have measured the air levels of isoflurane using static samplers. Anaesthetic mean daily concentrations ranged from 3.5 to 41.5 ppm in room A, from 4.1 to 24.4 ppm in room B, from 9.5 to 30.4 ppm in room C above all depending on the length and the number of surgical operations. The Authors emphasize the need of suitable prevention measures.

Liver function following hypovolemic hypotension in rats anaesthetized with halothane or enflurane

Rats which had approximately 25-30% of their calculated blood volume removed were exposed to halothane (1%) or enflurane (2%) in 33% oxygen for 30 min. Hepatic function was evaluated by determining, at various time intervals, serum activities of glutamic-oxalacetic and glutamic-pyruvic transaminase, acid phosphatase and gamma-glutamyl-transpeptidase. In this model serum enzyme activities and animal mortality were significantly increased when hypovolemic hypotension was induced during halothane anaesthesia. The same events did not occur in bleeding animals anaesthetized with enflurane. The marked disparity in hepatic dysfunction and mortality between halothane and enflurane-anaesthetized rats during hypovolemic hypotension may be explained by the more pronounced decrease of oxygen available for the liver and production of reductive toxic intermediates in animals exposed to halothane.

Stimulation of drug-metabolizing enzymes by nitrous oxide in the rat

Wistar male rats were subchronically (150 h continuously) or chronically (5 h daily for 15 days) exposed to a 50% nitrous oxide/oxygen mixture. As an index of enzyme induction liver N-demethylase and benzo(a)pyrene-hydroxylase activities, serum gamma-glutamyltranspeptidase activity, urinary d-glucaric acid and pentobarbital sleeping time were evaluated in comparison with a control group. No effect was observed after subchronic exposure to the anaesthetic gas. Chronic exposure, on the contrary, decreased pentobarbital sleeping time, increased urinary d-glucaric acid, liver N-demethylase and serum gamma-glutamyltranspeptidase activities. No increase of liver benzo(a)pyrene-hydroxylase was observed. Chronic nitrous oxide exposure under appropriate conditions can modify some enzymes, metabolizing drugs and xenobiotic compounds.

Analgesic interaction between nitrous oxide and delta-9-tetrahydrocannabinol in the rat

The analgesic activities of a 75:25% nitrous oxide-oxygen mixture administered for 15 min, of delta-9-tetrahydrocannabinol (THC) 10 mg kg-1 i.p., and of a combination of both, were evaluated in the rat by tail-flick and hot-plate tests. The nitrous oxide-oxygen mixture produced a significant increase in the pain threshold. The analgesic activity of THC was similar in extent but of longer duration than that of nitrous oxide. The cannabinoid also induced some locomotor and behavioural modifications. When both THC and the nitrous oxide-oxygen mixture were administered, a significant potentiation of the analgesic response was produced, without modification of the locomotor and behavioural responses that were induced by THC alone. Such mixtures may prove of value in the control of chronic pain in man.

[Effects of nitrous oxide on the female gonad in the rat]

Female rats have been exposed (24 hours for 15 days) to N2O 60% in normo-oxic blend of N2 and O2. Vaginal smears have been observed daily. At the end of the experiment the ovaries have been removed and the following morphological parameters have been statistically evaluated: number of evolutive follicles and corpora lutea, amount of interstitial tissue. Our results seem to account for a remarkable toxic effect of N2O on the rat gonad. Such effect is testified by alterations of the oestrous cycle and, at the ovary, a decrease in the number of evolutive follicles and functioning corpora lutea and by a sharp increase of atretic phenomena.

Analgesic effect of aprotinin in the rat and its inhibition by naloxone

Experiments were performed on rats using two analgesimetric tests (tail-flick; hot-plate) before and after injection i.v. of graded doses of aprotinin (12.5, 25.0 and 50 KIU g-1). A dose-related analgesic effect was noted with both tests. Prior administration of naloxone 0.001 mg g-1 i.p. inhibited the analgesic action.