The Doyle-Saleh blink reflex.

OBJECTIVES: When performing septoplasty or septorhinoplasty, we have observed that patients blink on injection of local anaesthetic (lidocaine 1 per cent with adrenaline 1:80 000) into the nasal mucosa of the anterior septum or vestibular skin, despite appropriate general anaesthesia. This study sought to quantify this phenomenon by conducting a prospective audit of all patients undergoing septoplasty or septorhinoplasty. METHODS: Patients were observed for a blink reflex at the time of local anaesthetic infiltration into the nasal vestibule. Also measured at this point were propofol target-controlled infusion levels, remifentanil rate, bispectral index, blood pressure, heart rate, pupil size and position, and patient movement. RESULTS: There were 15 blink reflexes in the 30 patients observed. The average bispectral index value was 32.75 (range, 22-50) in the blink group and 26.77 (range, 18-49) in the non-blink group. No patients moved on local anaesthetic injection. CONCLUSION: The blink reflex appears to occur in 50 per cent of patients, despite a deep level of anaesthesia. Without an understanding and appreciation of the blink reflex, this event may result in a request to deepen anaesthesia, but this is not necessary and surgery can proceed safely.

A comparison of remifentanil and fentanyl in patients undergoing carotid endarterectomy.

BACKGROUND AND AIM: We investigated the haemodynamic stability and emergence characteristics of isoflurane/nitrous oxide anaesthesia supplemented with remifentanil or fentanyl in patients undergoing carotid endarterectomy. METHODS: Anaesthesia was induced with propofol (1-2 mg kg-1) and either remifentanil (0.5 microgram kg-1) or fentanyl (1 microgram kg-1), followed by an infusion of remifentanil (0.2 microgram kg-1 min-1) or fentanyl (2 micrograms kg-1 h-1). RESULTS: There were no significant differences between the groups in haemodynamic variables, postoperative pain, nausea or vomiting. After induction there was a significant decrease in mean arterial pressure for both groups (P < 0.001) and a decrease in heart rate (P = 0.001) in the remifentanil group. In both groups these haemodynamic changes continued during maintenance of anaesthesia (P < 0.05). The time to eye opening after surgery was significantly shorter with remifentanil compared with fentanyl (6.62 +/- 3.89 vs. 18.0 +/- 15.18 min, P = 0.015). CONCLUSION: Remifentanil appears to be a comparable opioid to fentanyl when supplementing isoflurane/nitrous oxide anaesthesia for carotid endarterectomy.

Proportion positive for Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, Toxoplasma, and human immunodeficiency virus types 1 and 2 in heterophile-negative patients with an absolute lymphocytosis or an instrument-generated atypical lymphocyte flag.

OBJECTIVES: To determine the proportion of patients with evidence of an acute infection due to Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), Toxoplasma, or human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) in heterophile-negative patients with an absolute lymphocytosis or an instrument-generated atypical lymphocyte flag, and to develop a cost-effective testing algorithm for managing such heterophile-negative patients. DESIGN: We conducted a prospective investigation of 70 selected outpatients who tested negative for heterophile antibody in association with an absolute lymphocytosis or instrument-generated atypical lymphocyte flag. The control population consisted of 50 patients who were heterophile negative and had a normal absolute lymphocyte count and no instrument-generated atypical lymphocyte flag. SETTING: A large outpatient laboratory system. INTERVENTION: Viral serology for HHV-6 was performed by immunofluorescence, and all other serologies were performed by enzyme-linked immunoassay. All testing was for immunoglobulin (Ig) M antibodies, except in the case of HIV. RESULTS: The proportion of study patients positive for EBV was 40% (28/70); for CMV, 39% (27/70); for HHV-6, 25% (16/65); for Toxoplasma, 3% (2/70); and for HIV, 0% (0/70). All 50 control patients were negative for EBV IgM antibodies. When patients with more than 1 positive viral test were excluded from analysis, positivity was 20% (9/45) for EBV, 22% (10/45) for CMV, 9% (4/45) for HHV-6, and 2% (1/45) for Toxoplasma. Utilizing hypothesis-generating logistic regression models, Downey type II atypical lymphocytes were significantly associated with EBV positivity (P =.006), while Downey type III lymphocytes were significantly associated with HHV-6 positivity (P =.016), and there was a trend for the association of Downey type I lymphocytes with CMV positivity (P =.097). CONCLUSIONS: A positive viral serology was identified in 70% of study patients. Multiple positive serologies complicate establishing a definitive diagnosis. Potential cost savings may be associated with the use of an appropriate testing algorithm.

Burst suppression or isoelectric encephalogram for cerebral protection: evidence from metabolic suppression studies.

Metabolic suppression may have a role in cerebral protection. It is often assumed that the cerebral metabolic and protective effects of qualitative burst suppression are similar to those of the isoelectric encephalogram (EEG). We have examined the effect of different degrees of EEG suppression on blood flow and oxygen difference during general anaesthesia. We studied 11 patients undergoing general anaesthesia for resection of acoustic neuromas. The study was performed after surgery with propofol and remifentanil anaesthesia. Transcranial Doppler ultrasonography and jugular bulb venous saturations were measured at values of EEG suppression: 0%, 50% and 100% (isoelectric EEG). Data from nine patients were suitable for analysis. There were no significant differences in mean arterial pressure, heart rate or PaCO2 during EEG activity, 50% burst suppression ratio or isoelectric EEG. There was a significant decrease in middle cerebral artery flow velocity (vmca) with increasing EEG suppression (0% suppression, mean 38 (SEM 4) cm s-1; 50% suppression, 29 (3) cm s-1; and 100% suppression, 24 (2) cm s-1; P < 0.05). Jugular bulb venous saturations did not change consistently with the change in EEG activity, indicating intact flow-metabolism coupling. We conclude that the degree of EEG suppression had a significant effect on blood flow. If flow-metabolism coupling is maintained, the assumption that cerebral metabolism during 50% EEG burst suppression is equivalent to isoelectric EEG may not be justified. If cerebral protection is related to brain metabolism, then an isoelectric EEG may give more cerebral protection than 50% burst suppression.

Evaluation of the microbiology of chronic ethmoid sinusitis.

In a prospective study, patients with the diagnosis of chronic ethmoid sinusitis were evaluated microbiologically by using biopsy specimens of the ethmoid sinus mucosa. Microbiology cultures were performed on 94 specimens from 59 patients. Staphylococcus aureus and members of the family Enterobacteriaceae were the most frequent classical pathogenic bacteria isolated. Coagulase-negative staphylococci were the most common overall isolates. Streptococcus pneumoniae and Haemophilus influenzae were infrequent isolates. No anaerobes, viruses, or Chlamydia trachomatis organisms were identified. Results of this study showed organism isolation frequencies different from those found in other studies of chronic sinusitis reported in the literature. The predominance of S. aureus and members of the family Enterobacteriaceae could have an effect on the antimicrobial therapy for chronic ethmoid sinusitis.

Identification of Yersinia species by the API 20E.

A prospective study was performed to assess the effectiveness of the API 20E in the identification of 183 Yersinia isolates incubated at 28 degrees C for 18 to 24 h. The results showed an overall correct-identification rate of 90%, with positive predictive values for Yersinia enterocolitica and Yersinia frederiksenii of 94 and 92%, respectively. Yersinia intermedia results were unacceptable.

Epidemiology and pathogenicity of Blastocystis hominis.

A prospective study was performed on a large outpatient population to evaluate the epidemiology and pathogenicity of Blastocystis hominis. Patients with stool specimens positive for B. hominis and negative for other bacterial and parasitic pathogens were sent a questionnaire and were requested to submit a follow-up specimen for ova-and-parasite examination. B. hominis was identified in 530 of 16,545 specimens (3.2%). There was a spectrum of clinical-pathological presentations in the 143 patients evaluated. An asymptomatic carrier state was seen in 19 patients. Fifteen patients had an illness consistent with acute self-limited B. hominis gastroenteritis, and 21 patients had chronic gastroenteritis associated with B. hominis. In the epidemiological evaluation of 130 patients, the most common symptoms were watery diarrhea, abdominal pain, and gas. We did not find a statistically significant association between the number of organisms present and the disease state. In summary, our results are consistent with a role for B. hominis in acute and chronic gastroenteritis; however, further detailed studies are necessary to determine whether that role is one of association or causation.

Clinical and microbiological evaluation of four culture methods for the diagnosis of peritonitis in patients on continuous ambulatory peritoneal dialysis.

A prospective study was performed to evaluate four culture methods for the diagnosis of bacterial peritonitis in patients on continuous ambulatory peritoneal dialysis. Peritonitis was present in 44 of 85 patient admissions (52%). The overall sensitivity of the culture methods in detecting peritonitis was 66%. The sensitivities of the individual methods were as follows: bag culture method, 61%; blood culture broth method, 51%; filter method, 54%; and plate method, 39%. Our broad definition of peritonitis resulted in lower sensitivities. A combination of the bag and blood culture broth methods detected all positive cultures.

Direct antimicrobial susceptibility testing of urines positive in the MS-2 urine screening program.

A study was performed using the Abbott MS-2 system, in which positive urine screening specimens were set up directly to an antimicrobial susceptibility test. These results were compared with standard techniques. The overall correlation for urines containing single pathogens was 95.4%. Results were available 5-8 hr after receipt by the laboratory.

The incidence of wound infection after stapled or sutured bowel anastomosis and stapled or sutured skin closure in humans and guinea pigs.

In a study of antimicrobial prophylaxis in colorectal surgery, a higher incidence of wound sepsis was noted in patients who underwent stapled rather than sutured anastomoses and skin closures. There were six wound infections in 69 patients (8.7%) who underwent nonstapled anastomoses compared with seven in 28 (25%) in whom GIA or EEA staplers were used (p = 0.003). Excluding the EEA-stapled cases, the infection rate was 29% (p = 0.022). In patients who underwent sutured anastomoses, there were no wound infections in 21 whose skin was closed with sutures compared with five in 38 patients (13%) with stapled skin closure (p = 0.082). In an experimental guinea pig model dual incisions were infected with Bacteroides fragilis and Escherichia coli. One incision was then closed with staples, the other with sutures. There was a statistically significant (p = 0.016) advantage to the use of staplers. The possible significance of these results is discussed.

Comparative analysis of two rapid, automated methods for determining aminoglycoside levels.

Two rapid automated methods, the Syva EMIT Autolab 6000 (Syva Corp., Syntex Diagnostics, Ottawa, Ontario, Canada) and the Abbott TDX (Abbott Diagnostics, Mississauga, Ontario, Canada) systems, for determining amikacin, gentamicin and tobramycin levels in serum were evaluated for accuracy, reproducibility, and cost. Both methods had a high degree of accuracy and reproducibility in assaying gentamicin, amikacin, and tobramycin. The Abbott TDX required an average of only 1 min and 43 s for a single assay compared with 4 min and 15 s for the Syva EMIT automated system. Excluding the capital cost of equipment, the cost per assay by the Abbott TDX was +3.55 Canadian compared with +3.00 Canadian with the Syva EMIT automated system. Both systems performed well during this evaluation in a general diagnostic laboratory, but the Syva EMIT required more daily maintenance than the Abbott TDX system.

Herpes zoster ophthalmicus with contralateral hemiplegia: identification of cause.

A patient with herpes zoster ophthalmicus developed hemiparesis that at first responded to steroids but, when these were reduced, culminated in massive cerebral infarction and death. The cause was an extensive necrotizing arteritis of large and small cerebral arteries. Herpes-like virions were identified in smooth muscle cells of the middle cerebral artery.