Percutaneous Closure of Post-Infarct Left Ventricular Pseudoaneurysm; A Review of Literature

Left ventricular pseudoaneurysm is a well-known complication of myocardial infarction and open-heart surgery and has recently been described as succeeding transapical transcatheter aortic valve replacement (TAVR). While surgical intervention is the conventional therapeutic approach, transcatheter closure can be considered in patients at high risk for surgical procedures. In this article, we present a post-myocardial infarction pseudoaneurysm for which closure was done via retrograde left ventricular (LV) access using an Amplatzer Septal Occluder, and provide a review of recent literature focusing on indications and outcomes of the different percutaneous techniques and devices.

Urinary biomarkers for early detection of platinum based drugs induced nephrotoxicity

BACKGROUND

Nephrotoxicity is a major hazard complicating the use of platinum based drugs (PBD), which can hinder using higher doses protocols to maximize the therapeutic gain. Shortage of serum creatinine level as an accurate biomarker for acute kidney injuries (AKI) necessitates searching for novel biomarkers with better sensitivity and specificity in patients on PBD.

METHODS

In a prospective cohort design, 132 patients receiving PBD were selected for the study. AKI was diagnosed by continuous follow up of serum creatinine level according to Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 2012. Serum creatinine and urinary biomarkers (KIM-1, NGAL and cystatin C) was measured in the day of treatment and for 3 days after PBD cycle.

RESULTS

AKI occurred in 35 patients (26.52% of patients). KIM-1, Cystatin C, and NGAL showed significant increase in samples collected in the day of AKI in comparison to their corresponding basal levels (P <  0.0001). In addition, significant increase in urinary levels of the biomarkers in samples collected 1 day before AKI in comparison to their basal levels (P <  0.0001, P <  0.0001, and P = 0.013 for KIM-1, NGAL and Cystatin C respectively). Furthermore KIM-1 data showed a significant increase 2 days before serum creatinine rise in comparison to the corresponding KIM-1 levels in patients who developed AKI (P = 0.001).

CONCLUSIONS

Urinary KIM-1, Cystatin C and NGAL can predict PBD induced AKI in earlier stages than serum createnine. KIM-1 is the most sensitive biomarker for early detection of AKI in patients receiving PBD.

A novel European H5N8 influenza A virus has increased virulence in ducks but low zoonotic potential

We investigated in a unique setup of animal models and a human lung explant culture biological properties, including zoonotic potential, of a representative 2016 highly pathogenic avian influenza virus (HPAIV) H5N8, clade 2.3.4.4 group B (H5N8B), that spread rapidly in a huge and ongoing outbreak series in Europe and caused high mortality in waterfowl and domestic birds. HPAIV H5N8B showed increased virulence with rapid onset of severe disease and mortality in Pekin ducks due to pronounced neuro- and hepatotropism. Cross-species infection was evaluated in mice, ferrets, and in a human lung explant culture model. While the H5N8B isolate was highly virulent for Balb/c mice, virulence and transmissibility were grossly reduced in ferrets, which was mirrored by marginal replication in human lung cultures infected ex vivo. Our data indicate that the 2016 HPAIV H5N8B is avian-adapted with augmented virulence for waterfowl, but has low zoonotic potential. The here tested combination of animal studies with the inoculation of human explants provides a promising future workflow to evaluate zoonotic potential, mammalian replication competence and avian virulence of HPAIV.

The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene)

Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g(-1) in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.

Comparison of different scoring systems in predicting short-term mortality after liver transplantation

BACKGROUND

Many scoring systems have been used in predicting the outcomes of liver transplantations. The aim of this study was to compare between 4 scoring systems-Sequential Organ Failure Assessment (SOFA), Model for End-Stage Liver Disease, Acute Physiology and Chronic Health Evaluation II, and Child Turcotte-Pugh -among patients who underwent living-donor liver transplantation (LDLT) seeking to evaluate the best system to correlate with post-operative outcomes.

METHODS

This study retrospectively reviewed the medical records of 53 patients who had received LDLT in a tertiary care hospital from January 2005 to December 2010. Demographic, clinical, and laboratory data were recorded. Each patient was assessed by use of 4 scoring systems before transplantation and on post-operative days 1 to 7 and at 3 months.

RESULTS

The overall 3-month survival rate was 64%. The pre-transplant SOFA score had the best discriminatory power; moreover, the SOFA score on post-operative day 7 had the best Youden index (.875). The survival rate at 3-month follow-up after liver transplantation differed significantly (P = .00023, highest area under the receiver operator characteristic curve = .952) between patients who had SOFA scores <8 and those had SOFA score >8 on post-liver transplant day 7. This study also demonstrated that respiratory rate (P = .017) and serum bilirubin level (P = .048) and duration of intensive care unit stay (P = .04) are significant risk factors related to early mortality after LDLT.

CONCLUSIONS

The pre-transplant SOFA score was a statistically significant predictor of 3-month mortality; SOFA score on post-liver transplant day 7 had the best discriminative power for predicting 3-month mortality.

Gastric mucosa-associated lymphoid tissue lymphoma associated with pancreatic non-Hodgkin's lymphoma: A case report

Mucosa-associated lymphoid tissue (MALT) lymphomas are extranodal lymphomas that arise from B lymphocytes located in the marginal zone of lymphoid follicles. Although, there is a substantial amount of lymphoid tissue in the gastrointestinal tract, MALT lymphomas usually arise in chronically inflamed sites that are normally devoid of lymphoid tissue. The best example is gastric MALT lymphoma that is almost always associated with Helicobacter pylori. Primary pancreatic lymphoma (PPL) is an extremely rare tumor (1% incidence) and is often confused with pancreatic adenocarcinoma. By suspecting PPL on clinical and imaging grounds, surgery and its associated complications can be avoided, since the mainstay of the treatment is non-surgical strategies including chemotherapy. We represent a case of a 45-year-old male presented with abdominal pain and vomiting. Upper endoscopy showed multiple gastric ulcers, biopsies revealed non-specific inflammatory ulcers. The patient was given 4-weeks course of proton pump inhibitor with no improvement. After few months, he complained of severe abdominal pain relieved by leaning forward and associated with repeated vomiting. Upper endoscopy revealed multiple umbilicated gastric masses, 10-20 mm in diameter. Biopsies were taken, histopathology and immunohistochemistry revealed MALT lymphoma. Endoscopic ultrasonography was done to the patient and it showed a pancreatic head mass, fine-needle aspiration was done, histopathology and immunohistochemistry revealed PPL. The patient received chemotherapy for MALT lymphoma with near total relief of symptoms and disappearance of gastric and pancreatic masses.

CONCLUSION

This is a rare case having MALT lymphoma associated with PPL.

Role of high resolution ultrasonography/endoscopic ultrasonography and elastography in predicting lymph node malignancy

OBJECTIVE

To evaluate the role of high resolution ultrasonography (US) and endoscopic ultrasonography (EUS)-elastography in predicting malignant lymphadenopathy.

METHODS

This prospective study included 88 patients who underwent EUS or US examination of different groups of lymph nodes (LNs). The classification as benign or malignant based on the real-time elastography pattern and the B-mode US/EUS images was compared to the final diagnosis obtained by EUS or US guided fine-needle aspiration cytology (FNAC), Tru-Cut biopsy or excisional biopsy and follow-up in benign lesions not indicated for biopsy for at least 12 months.

RESULTS

Regarding the echogenicity, 98.3% of the benign LNs were hyperechoic, 1.7% were hypoechoic, while 89.7% of the malignant LNs were hypoechoic, 3.4% were heterogenous and 6.9% were hyperechoic. With cut-off value of 1.93, the sensitivity of longitudinal to transverse ratio was 73% and the specificity was 100%. Score 1 elastography had specificity of 100% in diagnosis of benign LNs, sensitivity was 76.3%, positive predictive value (PPV) was 100%, negative predictive value (NPV) was 84.7% while Score 2 had a sensitivity of 60%, specificity of 31.5%, PPV of 15.3%, NPV of 79.3%. Score 3 had a sensitivity of 70.2%, specificity of 100%, PPV of 13.8%, NPV of 100% in detecting malignancy while Score 4 had a sensitivity of 85.5%, specificity of 100%, PPV of 100%, NPV of 65.5%.

CONCLUSION

Elastography is a promising diagnostic modality that may complement standard ultrasound and EUS and help guide FNAC during staging of LNs.

Synthesis and characterization of two-dimensional Nb4C3 (MXene)

By etching Nb₄AlC₃ powders in hydrofluoric acid, a phase-pure, highly conductive, Nb₄C₃ MXene – the second with formula M₄X₃ – was produced. The latter's structure was investigated using pair distribution function analysis.

Spinal gene expression profiling and pathways analysis of a CB2 agonist (MDA7)-targeted prevention of paclitaxel-induced neuropathy

AIMS

Patients receiving paclitaxel often develop peripheral neuropathies. We found that a novel selective cannabinoid CB2 receptor agonist (MDA7) prevents paclitaxel-induced mechanical allodynia in rats and mice. Here we investigated gene expression profiling in the lumbar spinal cord after 14-day treatment of MDA7 in paclitaxel animals and analyzed possible signaling pathways underlying the preventive effect of MDA7 on paclitaxel-induced neuropathy.

METHODS

Peripheral mechanical allodynia was induced in rats or mice receiving intraperitoneal (i.p.) injection of paclitaxel at a dose of 1mg/kg daily for four consecutive days. MDA7 was administered at a dose of 15mg/kg 15min before paclitaxel and then continued daily for another 10days. Whole-genome gene expression profiling in the lumbar spinal cord of MDA7 and paclitaxel-treated rats was investigated using microarray analysis. The Ingenuity pathway analysis was performed to determine the potential relevant canonical pathways responsible for the effect of MDA7 on paclitaxel-induced peripheral neuropathy.

RESULTS

We observed that the inflammatory molecular networks including tumor necrosis factor (TNF), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), transforming growth factor beta (TGFβ), and mitogen-activated protein kinases (MAPK) signaling are most relevant to the preventive effect of MDA7 on paclitaxel-induced peripheral neuropathy. In addition, genes encoding molecules that are important in central sensitization such as glutamate transporters and N-methyl-d-aspartate receptor 2B (NMDAR2B), and neuro-immune-related genes such as neuronal nitric oxide synthase (nNOS1), chemokine CX3CL1 (a mediator for microglial activation), toll-like receptor 2 (TLR2), and leptin were differentially modulated by MDA7.

CONCLUSION

The preventive effect of MDA7 on paclitaxel-induced peripheral allodynia in rats may be associated with genes involved in signal pathways in central sensitization, microglial activation, and neuroinflammation in the spinal cord.

Surgical anatomy of the extended middle cranial fossa approach

The extended middle cranial fossa approach includes removal of the petrous bone from its subtemporal surface in order to expose widely the internal auditory canal and the posterior fossa dura around its porus while preserving all the important and closely related anatomical structures. We have dissected 25 temporal bones and five fresh cadavers in order to define the limits of this approach. Measurements were obtained between the different structures to find reliable angles and distances that could guide working in this area. A new method of identification of the internal auditory canal is discussed based on the measurements taken.The results of the present work showed wide variations in the different structures. The arcuate eminence was coincident with the superior semicircular canal in only 48% of bones. Dehiscence of the geniculate ganglion and of the internal carotid artery was noted in 16% and 20% of specimens, respectively. The angles measured between the different structures showed great variations. However, the angle between the internal auditory canal and superior petrosal sinus was constant. Though the extended middle cranial fossa is a versatile approach, it affords a limited access to the cerebellopontine angle. A thorough understanding of the complex and variable anatomy of this area is necessary should this approach be utilized.

Pattern of acute poisoning in Al-Qassim region: a surveillance report from Saudi Arabia, 1999-2003

We reviewed all registered cases of acute chemical poisoning reporting to the preventive medicine department in the Qassim Region of Saudi Arabia from 1999 to 2003. The number of cases increased from 66 to 114 during the study period. Mean age of patients was 17.7 years, and over 39% were children aged < or = 5 years. Pesticides were the most common chemical involved; paracetamol and other analgesics were also frequently reported. The oral route was the most frequent, while vomiting was the commonest symptom. Nine deaths were recorded, of which 4 were due to pesticide poisoning. In line with the global trend, acute chemical poisoning is growing as a major health issue in the Qassim Region.

Drug-resistant tuberculosis in Egyptian children using Etest

AIM

Etest (AB Biodisk, Solna, Sweden) is a new rapid and accurate alternative for susceptibility testing. It also can measure the minimal inhibitory concentration. The aim of this study was to assess the prevalence of drug-resistant Mycobacterium TB (MT) in newly diagnosed tuberculous Egyptian children, and to determine the effectiveness of the Etest to detect drug-resistant MT.

METHODS

This prospective study included 150 newly diagnosed pulmonary and extrapulmonary tuberculous children. The organism was isolated and identified after decontamination. Antimicrobial susceptibility testing was performed by proportion method using Lowenstein-Jensen medium (PMLJ) and Etest. Minimal inhibitory concentration for both first and second line anti tuberculous drugs was determined by Etest. Comparison between the two methods was done.

RESULTS

Age range was 6 months - 15 years (mean of 7.4+/-3.3). Pulmonary tuberculosis (TB) and extrapulmonary cases were 85/150 (55.3%) and 67/150 (44.7%) respectively. Seventy three isolates of MT were obtained from patients or contacts. Using Etest, the over all drug resistant of MT was 24.7% which is resistance to one drug (any drug). Resistance to first-line drugs; isoniazid, rifampicin, streptomycin and ethambutol was 5.4%, 2.7%, 6.8% and 1.4% respectively. Rifampicin resistance strongly correlated with isoniazid resistance. The prevalence of multi-drug resistance was 2.7%. Resistance to second line was 2.7% for amikacin and 1.4% for ciprofloxacin. Etest showed an overall specificity of 97.89 and sensitivity of 81.8. Overall agreement of Etest with reference proportion method range was 94.5-100%.

CONCLUSION

Etest appears to be a good alternative method for testing susceptibility of Mycobacterium tuberculosis.

Neuromuscular monitoring and postoperative residual curarisation: a meta-analysis

We conducted a meta-analysis to examine the effect of intraoperative monitoring of neuromuscular function on the incidence of postoperative residual curarisation (PORC). PORC has been considered present when a patient has a train-of-four (TOF) ratio of < 0.7 or < 0.9. We analysed data from 24 trials (3375 patients) that were published between 1979 and 2005. We excluded data on mivacurium from this meta-analysis because only three studies had examined the incidence of PORC associated with its use. Long- and intermediate-acting neuromuscular blocking drugs had been given to 662 and 2713 patients, respectively. Neuromuscular function was monitored in 823 patients (24.4%). A simple peripheral nerve stimulator was used in 543 patients, and an objective monitor was used in 280. The incidence of PORC was found to be significantly lower after the use of intermediate neuromuscular blocking drugs. We could not demonstrate that the use of an intraoperative neuromuscular function monitor decreased the incidence of PORC.

Tunneled catheters' outcome optimization among diabetics on dialysis through antibiotic-lock placement

Efficacy and safety of antibiotic 'locks', in prevention of thrombotic and infectious complication-related morbidity and mortality, among diabetics dialyzed through tunneled-cuffed catheters (TCCs) has not been effectively investigated. This trial was designed to investigate the outcome of TCCs (n = 109), inserted among 96 diabetic end-stage renal disease patients (March 2002-February 2003), by comparing the catheter thrombosis, catheter-related bloodstream infections (CRBSI), catheter survival, and mortality rates, between the cohorts of 49 patients who had TCCs (n = 51) 'locked' with cefotaxime/heparin (group I) and 47 patients with TCCs (n = 58) filled with standard heparin (group II). Thrombosis was defined as the inability to use catheter at a blood flow of 200 ml/min despite intraluminal thrombolysis. Primary end points were catheter thrombosis and CRBSI; elective catheter removal and CRBSI-related death led to sensor of TCCs follow-up. Patients with intraluminal cefotaxime/heparin lock, on cumulative survival analysis, showed a superior thrombosis-free (86.3 vs 63.8%, P = 0.023, log rank), infection-free (72.9 vs 27.1%, P = 0.004, log rank), and thrombosis- and infection-free TCC survival (78.4 vs 37.9%, P = 0.001, log rank) at 365 days, besides having significantly lower incidence of CRBSI (1.56 vs 3.68 episodes/1000 catheter days, P < 0.0001) and CRBSI-related mortality (9.8 vs 23.4%, P = 0.015), compared with the heparin-alone group. Deployment of cefotaxime-heparin 'lock' enhances catheter survival; reduces thrombotic and infectious complications and ensuing mortality, among diabetics on dialysis. However, further studies are needed to define the long-term implications of antibiotic locks in terms of the risk of emergence of antimicrobial resistance.

Melatonin vs. midazolam premedication in children: a double-blind, placebo-controlled study

BACKGROUND AND OBJECTIVE

Unlike midazolam, melatonin premedication is not associated with cognitive impairment in adults despite its anxiolytic properties. The use of melatonin as a premedicant in children has not been reported. This randomized, double-blind, placebo-controlled study compared the perioperative effects of different doses of melatonin and midazolam in children.

METHODS

Seven groups of children (n = 15 in each) were randomly assigned to receive one of the following premedicants. Midazolam 0.1, 0.25 or 0.5 mg kg(-1) orally, melatonin 0.1, 0.25 or 0.5 mg kg(-1) orally each mixed in 15 mg kg(-1) acetaminophen, or placebo only (15 mg kg(-1) acetaminophen). Anxiety and temperament were evaluated before and after administration of the study drug, on separation from parents and on the introduction of the anaesthesia mask. At week 2 postoperatively, the behaviour of the children was measured by the Post Hospitalization Behaviour Questionnaire.

RESULTS

Melatonin or midazolam each in doses of 0.25 or 0.5 mg kg(-1) were equally effective as premedicants in alleviating separation anxiety and anxiety associated with the introduction of the anaesthesia mask. A trend was noted for midazolam to prolong recovery times as the dosage increased. The use of melatonin was associated with a lower incidence (P = 0.049) of excitement at 10 min postoperatively, and a lower incidence (P = 0.046) of sleep disturbance at week 2 postoperatively than that observed with midazolam and control groups. No postoperative excitement was noted in the melatonin groups at 20, 30 and 45 min.

DISCUSSION

Melatonin was not only as effective as midazolam in alleviating preoperative anxiety in children, but it was also associated with a tendency towards faster recovery, lower incidence of excitement postoperatively and a lower incidence of sleep disturbance at week 2 postoperatively.

Pharmacological effects of intravenous melatonin: comparative studies with thiopental and propofol

BACKGROUND

Possible utility of high-dose i.v. melatonin as an anaesthetic adjuvant has not been studied. This study compared its effects with thiopental and propofol.

METHODS

Sprague Dawley rats were assigned to receive bolus or cumulative i.v. doses of melatonin, thiopental or propofol. Righting reflex, hindpaw withdrawal to a noxious stimulus, response to tail clamping and haemodynamic effects were assessed.

RESULTS

Melatonin caused a dose-dependent increase in paw withdrawal threshold and the percent of rats displaying loss of the righting reflex. Melatonin was comparable to thiopental and propofol in terms of its rapid onset of hypnosis. The mean ED(50) values for loss of righting reflex were 5.4 (SEM 1.2), 12.5 (1.1) and 178 (1.1) mg kg(-1) for propofol, thiopental and melatonin, respectively. The percent of rats displaying loss of response to tail clamping was greater with propofol than with melatonin (P<0.05). Haemodynamic changes produced by melatonin or propofol were similar in onset and magnitude.

CONCLUSIONS

I.V. melatonin can exert hypnotic effects similar to those observed with thiopental and propofol. Melatonin exhibited significant antinociceptive effects but was less effective in abolishing the response to tail clamping.

Prevalence of hepatitis C antibodies among hemodialysis patients in Al-hasa region of saudi arabia

The prevalence of anti-HCV antibodies among hemodialysis (HD) patients was studied at King Fahad Hospital, Hofuf, Saudi Arabia. The records of 189 patients undergoing HD were reviewed. The overall prevalence of anti-HCV antibodies was 43.9%. Anti-HCV antibody prevalence was more common among female patients. There was no correlation between repeated blood transfusions and anti-HCV positivity as 4.8% of the patients who did not receive any blood transfusion during HD were positive for anti-HCV antibodies. A positive correlation was observed between the duration on dialysis and anti-HCV antibodies. An annual serocoversion rate of 6.8% was observed in this study.

Metabolic, hormonal and gastric fluid and pH changes after different preoperative feeding regimens

PURPOSE

To evaluate the metabolic, hormonal and gastric fluid and pH changes after administration of a small volume of different preoperative feeding regimens.

METHODS

In a prospective, randomized, double-blind study 375 adult patients were allocated to one of five groups. Patients ingested 60 ml honey, glucose-fructose-sucrose-maltose mixture (GFSM), apple juice or water two hours before surgery or continued their overnight fast (controls). Blood samples were obtained from an indwelling venous catheter before the administration of feeding regimens and before induction of anesthesia for determination of glucose, triglycerides, insulin, epinephrine and norepinephrine concentrations. Before anesthesia induction, patients were asked to grade the degree of thirst and hunger. After tracheal intubation residual gastric volume (RGV) was suctioned through an orogastric tube.

RESULTS

Administration of honey, GFSM, apple juice or water resulted in increases in RGV without changes in the gastric pH. The median RGV values were 15 ml in controls and 20-25 ml in other groups. Thirst was noted after administration of fluids containing sugars. Hunger was noted in the apple juice group. Plasma concentrations of glucose increased and triglycerides decreased after ingestion of fluids containing sugars. Plasma insulin concentrations decreased in GFSM and apple juice groups. Norepinephrine concentrations increased in the control, apple juice and water groups.

CONCLUSIONS

Small volumes of fluid increased RGV (P < 0.05). Apple juice resulted in increased incidence of thirst and hunger and plasma glucose and norepinephrine concentrations. Compared with GFSM or apple juice, honey had a gentler effect on plasma glucose and insulin concentrations.

Cost identification analysis for succinylcholine

The cost of a dose of succinylcholine from society's perspective equals the acquisition cost of the drug plus the cost of its adverse outcomes. We hypothesized that although the acquisition cost of succinylcholine is minimal, the true cost would be much larger. We reviewed the medical literature to identify the total cost of a dose of succinylcholine when administered for nonemergency purposes according to manufacturers' guidelines (i.e., to adults only). We found that 88% of the cost per dose of succinylcholine was for the chance of dying or sustaining permanent brain injury from anaphylactic or anaphylactoid reactions to succinylcholine. Consequently, the estimated cost per dose of succinylcholine was sensitive to the incidence of anaphylactic or anaphylactoid reactions to succinylcholine, the risk of severe injury from anaphylactic or anaphylactoid reactions, and the financial value of unforeseen instant death or permanent brain injury. The range for the cost per dose of succinylcholine was thus large, $9 to $93. Our best estimate of the cost per dose was $37. We conclude that the true cost per dose of succinylcholine from society's perspective is more than 20 times the acquisition cost. However, a precise costing requires better knowledge of the incidence and consequences of anaphylactic or anaphylactoid reactions to succinylcholine.

IMPLICATIONS

The true cost of succinylcholine is more than 20 times the acquisition cost of the drug. The estimated cost is very sensitive to the risk and cost of patients dying or sustaining brain injury from anaphylactic or anaphylactoid reactions to succinylcholine.

The use of low-dose rocuronium to facilitate laryngeal mask airway insertion

In this two-phase study, the efficacy of low-dose rocuronium to facilitate laryngeal mask airway (LMA) insertion was evaluated. First, the onset time of 100, 150 and 300 micrograms.kg-1 rocuronium was determined using mechanomyography in three groups of patients (n = 10 in each) anaesthetized with propofol-fentanyl-nitrous oxide. In the second part, 100, 150 or 300 micrograms.kg-1 rocuronium or placebo was administered randomly to four groups of patients (n = 50 in each) in a double-blind manner. Following this, anaesthesia was induced with propofol 2.5 mg.kg-1. Patients in the group of 300 micrograms.kg-1 rocuronium or placebo received propofol after 1.5 min. Patients in the group of 100 or 150 micrograms.kg-1 rocuronium received propofol after 3 min. The LMA was inserted 90 sec later. Immediately before the induction of anaesthesia, patients were questioned about the symptoms of neuromuscular block. In phase 1, onset times were 180 sec (SD 41), 191 sec (59) and 89 sec (34), respectively. In phase 2, insertion of the LMA was graded as easy in 90.6% of patients receiving rocuronium, compared with 42% of patients who had only propofol (P < 0.05). Rocuronium improved the overall ease of LMA insertion. LMA insertion was graded easy in 80% of patients who received 100 micrograms.kg-1 rocuronium. The incidence of unpleasant effects was greatest with 300 micrograms.kg-1 rocuronium. The optimal dose needed to facilitate LMA insertion with minimal unpleasant effects appeared to be 100 micrograms.kg-1 rocuronium.

Dose-response relationships for edrophonium and neostigmine antagonism of atracurium and cisatracurium-induced neuromuscular block

PURPOSE

To study the dose-response relationships for neostigmine and edrophonium during antagonism of neuromuscular block induced by atracurium and cisatracurium.

METHODS

One hundred and twenty eight, ASA group 1 or 2 adults were given either 0.5 mg x kg(-1) atracurium or 0.1 mg x kg(-1) cisatracurium during fentanyl-thiopental-nitrous oxide-isoflurane anesthesia. The neuromuscular block was measured by an acceleration-responsive transducer. Responses were defined in terms of percent depression in the first twitch (T1) and train-of-four (TOF) response. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg x kg(-1)) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg x kg(-1)) was administered by random allocation. Neuromuscular function in another sixteen subjects was allowed to recover spontaneously.

RESULTS

At five minutes, unlike edrophonium, neostigmine was equally effective against atracurium and cisatracurium with respect to T1 recovery. The neostigmine T1-ED50 was 10.3 +/- 1.06 (SEM) microg x kg(-1) after atracurium and 11.2 +/- 1.06) microg x kg(-1) after cisatracurium. The edrophonium ED50 was 157 +/- 1.07 microg x kg(-1) with atracurium and 47.4 +/- 1.07 microg x kg(-1) with cisatracurium, giving a neostigmine:edrophonium potency ratios of 15.2 +/- 1.7 and 4.2 +/- 0.41 (P < 0.001) for atracurium and cisatracurium, respectively. At 10 min neostigmine was 13 +/- 1.4 times as potent as edrophonium for achieving 50% TOF recovery after atracurium paralysis. After cisatracurium the potency ratio was 11.8 +/- 1.3 (NS).

CONCLUSIONS

Although there were differences at five minutes, neostigmine:edrophonium potency ratios at 10 min, were similar in both relaxants studied.

The comparative dose-response effects of melatonin and midazolam for premedication of adult patients: a double-blinded, placebo-controlled study

We designed this prospective, randomized, double-blinded, placebo-controlled study to compare the perioperative effects of different doses of melatonin and midazolam. Doses of 0.05, 0.1, or 0. 2 mg/kg sublingual midazolam or melatonin or placebo were given to 84 women, approximately 100 min before a standard anesthetic. Sedation, anxiety, and orientation were quantified before, 10, 30, 60, and 90 min after premedication, and 15, 30, 60, and 90 min after admission to the recovery room. Psychomotor performance of the patient was evaluated at these times also, by using the digit-symbol substitution test and Trieger dot test. Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation preoperatively compared with control subjects. Patients in the three midazolam groups experienced significant psychomotor impairment in the preoperative period compared with melatonin or placebo. After operation, patients who received 0.2 mg/kg midazolam premedication had increased levels of sedation at 90 min compared with 0.05 and 0. 1 mg/kg melatonin groups. In addition, patients in the three midazolam groups had impairment of performance on the digit-symbol substitution test at all times compared with the 0.05 mg/kg melatonin group. Premedication with 0.05 mg/kg melatonin was associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills or affecting the quality of recovery.

IMPLICATIONS

Premedication with 0.05 mg/kg melatonin was associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills or affecting the quality of recovery.

Wound closure tramadol administration has a short-lived analgesic effect

PURPOSE

To evaluate the effects of tramadol administration at wound closure on postoperative pain and analgesic requirements in patients undergoing laparoscopic cholecystectomy.

METHODS

In a prospective, randomized, double-blind study 80 patients were allocated into two groups (n = 40 in each) to receive either 200 mg tramadol or placebo i.v. at the time of wound closure. Postoperatively, all patients received tramadol from a patient-controlled analgesia (PCA) device. Pain, analgesic consumption, vital signs and side effects were recorded postoperatively for 24 hr.

RESULTS

Administration of 200 mg tramadol at the time of wound closure was associated with a short-lived (60 min) reduction in pain scores and PCA consumption compared with placebo. Although the time to first request for analgesia after surgery was longer in patients who received tramadol at wound closure, there was no difference between the two groups with respect to pain scores or to the requirements of postoperative analgesia over the next 23 hr. The cumulative PCA consumption of tramadol in 24 hr was 139.4+/-108 and 102.4+/-106 mg in the placebo and tramadol groups, respectively (P = 0.06).

CONCLUSIONS

Wound closure administration of 200 mg tramadol had a short-lived (60 min) analgesic effect but did not affect the long-term pain scores or analgesic requirements after laparoscopic cholecystectomy.

Assessment of auditory distance in a territorial songbird: accurate feat or rule of thumb?

Territorial passerines presumably benefit from their ability to use auditory cues to judge the distance to singing conspecifics, by increasing the efficiency of their territorial defence. Here, we report data on the approach of male territorial chaffinches, Fringilla coelebs, to a loudspeaker broadcasting conspecific song simulating a rival at various distances by different amounts of song degradation. Songs were degraded digitally in a computer-simulated forest emulating distances of 0, 20, 40, 80 and 120 m. The approach distance of chaffinches towards the loudspeaker increased with increasing amounts of degradation indicating a perceptual representation of differences in distance of a sound source. We discuss the interindividual variation of male responses with respect to constraints resulting from random variation of ranging cues provided by the environmental song degradation, the perception accuracy and the decision rules. Copyright 2000 The Association for the Study of Animal Behaviour.

Effects of song overlapping and alternating on nocturnally singing nightingales

The timing of songs during vocal interactions in male passerines is an important component in territorial signalling as it can reflect information on the singer's state or possibly its quality. Using interactive playback, I investigated effects of song alternation and song overlapping on the nocturnal singing behaviour of nightingales, Luscinia megarhynchos. Subjects timed their songs differently depending on whether the playback songs overlapped their songs or alternated with them. During overlapping treatments, subjects sang at higher rates and interrupted more songs than during alternating treatments. In addition, during alternating treatments subjects sang at higher rates when they had been exposed to the overlapping treatment than when the alternating treatment was the first treatment they had received. These latter responses indicate that timing of songs is not just an immediate effect such as to avoid signal masking but that prior experience with a rival influences the way an individual uses its song. The results thus suggest that not only song overlapping but also the timing of songs during alternating singing carries important information. Individual differences in response suggest further that state (e.g. arousal or motivation) or possibly quality of a territorial male is important for decisions on how it responds vocally. Copyright 1999 The Association for the Study of Animal Behaviour.

Predictive models for difficult laryngoscopy and intubation. A clinical, radiologic and three-dimensional computer imaging study

PURPOSE

To identify the variables most useful in predicting difficult laryngoscopy and intubation from various clinical, skeletal (lateral x-rays) and soft tissue (three-dimensional computed tomography imaging) measurements.

METHODS

Twenty-four adult patients in whom an unanticipated difficult tracheal intubation was identified according to established criteria were evaluated. Further, a control group of 32 patients in whom tracheal intubation was easily accomplished was studied. We applied multivariate discriminant analysis to clinical and radiological data of all patients to select those variables most useful in predicting difficult laryngoscopy and intubation. The receiver operating characteristic (ROC) curve was used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model.

RESULTS

With the clinical data alone, discriminant analysis identified four risk factors that correlated with the prediction of difficult laryngoscopy and intubation: thyrosternal distance, thyromental distance, neck circumference and Mallampati classification. With both clinical and radiological data, discriminant analysis identified five risk factors: thyrosternal distance, thyromental distance, Mallampati classification, depth of spine C2 and angle A (the most antero-inferior point of the upper central incisor tooth). The positive predictive value of this combined (clinical and radiological) model was greater than that of the clinical model alone (95.8% vs 87.5%, respectively). The areas under the ROC curves, that measure the probability of the correct prediction of the clinical and the combined models, were found to be 0.933 and 0.973, respectively.

CONCLUSIONS

These models can be used for predicting difficult laryngoscopy and intubation in clinical practice.

Premedication with melatonin: a double-blind, placebo-controlled comparison with midazolam

We have evaluated the perioperative effects of melatonin with those of midazolam in 75 women in a prospective, randomized, double-blind, placebo-controlled study. Patients were given sublingual midazolam 15 mg, melatonin 5 mg or placebo, approximately 100 min before a standard anaesthetic. Sedation, anxiety and orientation were quantified before, and 10, 30, 60 and 90 min after premedication, and 15, 30, 60 and 90 min after admission to the recovery room. Psychomotor performance was evaluated at these times also, using the digit-symbol substitution test (DSST) and the Trieger dot test (TDT). Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation before operation compared with controls. Midazolam produced the highest scores for sedation at 30 and 60 min after administration and significant psychomotor impairment in the preoperative period compared with melatonin or placebo. After operation, patients who received midazolam or melatonin premedication had increased levels of sedation at 30 min and impairment in performance on the DSST at 15, 30 and 90 min compared with controls. There were no significant differences between the three groups for anxiety levels or TDT performance after operation. Amnesia was notable only in the midazolam group for one preoperative event (entry into the operating room). Patient satisfaction was noted in the midazolam and melatonin groups only. We have demonstrated that melatonin can be used effectively for premedication of adult patients.