Nocturnal hypoxia in motor neuron disease is not predicted by standard respiratory function tests.

BACKGROUND: With increasing awareness of motor neuron disease (MND) in Australia, the approach to respiratory management of patients with this disease will more commonly face the respiratory physician. AIM: The aim of this study was to determine if standard respiratory function tests could determine the presence of nocturnal hypoxia (NH) in patients with MND. METHODS: Respiratory function tests were used to examine daytime respiratory function, and sleep studies were used to detect NH in 16 consecutive patients with MND and in 9 healthy control subjects. Demographic data, clinical parameters, respiratory function tests and sleep studies were obtained. Statistical analyses were carried out using t-tests and anova, where appropriate. RESULTS: NH was detected in 50% of patients with MND, with no hypoxic events detected in the control group. Standard respiratory function tests were not able to predict the presence of NH. CONCLUSION: There was no correlation between respiratory function tests and NH. This study emphasizes the inability of standard respiratory function tests to predict NH that may arise early in the course of MND.

Exotic meson decay to omegapi0pi-.

A partial-wave analysis of the mesons from the reaction pi(-)p --> pi(+)pi(-)pi(-)pi(0)pi(0)p has been performed. The data show b(1)pi decay of the spin-exotic states pi(1)(1600) and pi(1)(2000). Three isovector 2(-+) states were seen in the omegarho(-) decay channel. In addition to the well known pi(2)(1670), signals were also observed for pi(2)(1880) and pi(2)(1970).

Interference study of the chi c0(13P0) in the reaction -pp-->pi0pi0.

Fermilab experiment E835 has observed (-)pp annihilation production of the charmonium state chi(c0) and its subsequent decay into pi(0)pi(0). Although the resonant amplitude is an order of magnitude smaller than that of the nonresonant continuum production of pi(0)pi(0), an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance (-)pp channel. The product of the input and output branching fractions is determined to be B((-)pp-->chi(c0))xB(chi(c0)-->pi(0)pi(0))=(5.09+/-0.81+/-0.25)x10(-7).

Evaluation of the clinical efficacy of marbofloxacin (Zeniquin) tablets for the treatment of canine pyoderma: an open clinical trial.

The efficacy and field safety of marbofloxacin (Zeniquin) for the treatment of superficial and deep bacterial pyoderma were evaluated. Seventy-two dogs were treated with 2.75 mg kg-1 of marbofloxacin orally once daily for 21 or 28 days. Sixty-two dogs (86%) had superficial pyoderma and 10 (14%) had deep pyoderma. A history of prior pyoderma was reported in 39/72 dogs. Pretreatment aerobic bacteriologic cultures of skin lesions were performed in 47 cases and the predominant pathogen isolated was Staphylococcus intermedius. Treatment was successful in 62/72 (86.1%) dogs, improvement was noted in 6/72 (8.3%) dogs and treatment failed in 4/72 (5.6%) dogs. Adverse effects associated with treatment included listlessness, anorexia, vomiting, soft stool, flatulence and polydipsia; these adverse effects were seen in only 6/81 dogs. Marbofloxacin was safe and effective for the treatment of superficial and deep pyoderma in dogs at the dosage used in this study.

Observation of exotic meson production in the reaction pi- p --> eta'pi- p at 18 GeV/c.

An amplitude analysis of an exclusive sample of 5765 events from the reaction pi- p-->eta'pi- p at 18 GeV/c is described. The eta'pi- production is dominated by natural parity exchange and by three partial waves: those with J(PC) = 1(-+), 2(++), and 4(++). A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to eta'pi-. The dominant, exotic (non- qq) 1(-+) partial wave is shown to be resonant with a mass of 1.597+/-0.010(+0.045)(-0.010) GeV/c2 and a width of 0.340+/-0.040+/-0.050 GeV/c2. This exotic state, the pi1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states.

Neuropsychological function in obstructive sleep apnoea.

Patients with obstructive sleep apnoea (OSA) experience neuropsychological deficits falling broadly into the four areas of daytime sleepiness, cognitive deficits, reduced driving competence and impaired psychosocial well-being. Case-control studies of daytime function in OSA patients generally indicate moderate to severe daytime sleepiness using polysomnographic or self-rating assessments. Cognitive performance on tests of attention and concentration ability, visuomotor and constructional skills, verbal fluency, planning and problem-solving, memory and executive function may be mildly to moderately impaired. These two symptoms may contribute to a road traffic accident rate in OSA between two and seven times higher than that of normals, and to the high prevalence of minor psychiatric morbidity, and reductions in functional and health status, among patients. The daytime impairments associated with OSA are improved by continuous positive airway pressure (CPAP) therapy, although a lack of complete normalization has been suggested for objective sleepiness and some areas of cognitive function. The severity of sleepiness and cognitive impairments show weak and moderate correlations with frequency of sleep-disordered breathing in clinical and epidemiological studies. Experimental and clinical evidence supports a role for nocturnal physiological events of OSA, arousals and hypoxaemia, in directly or indirectly producing neuropsychological deficits, particularly those of sleepiness and cognitive deterioration.

Use of cervicothoracic junction pedicle screws for reconstruction of complex cervical spine pathology.

STUDY DESIGN: A retrospective review of 21 patients in which cervical pedicle screw fixation was used at C7 with or without upper thoracic pedicle screw fixation. OBJECTIVE: To evaluate the use of pedicle screw placement in the lower cervical spine. SUMMARY OF BACKGROUND DATA: The use of posterior cervical spine fixation, including lateral mass fixation, has become increasingly popular in recent years. However, lateral mass fixation at C7 is often hindered by lack of substantial high quality bone. The end level of long cervical spine constructs is frequently C7 or T1. Dissatisfaction with lateral mass fixation at C7 and T1 led the authors to use lower cervical pedicle screw fixation for several cervical spine disorders. METHODS: Twenty-one patients who had undergone cervical pedicle screw fixation at C7 were reviewed retrospectively. There were 12 males and 9 females, with an average age of 52 years. All pedicle screws were placed, after direct palpation of the pedicle, with a right angle nerve hook after laminoforaminotomy at C7. RESULTS: There were no neurologic complications related to pedicle screw placement, and no patient was symptomatically worse after the operation. Six patients with root pathology improved. Of 14 patients with cervical myelopathy, 12 improved at least one Nurick grade, and 2 had no improvement. There were no failures of fixation or complications related to pedicle fixation at a minimum of 1 year follow-up. CONCLUSION: Pedicle screws in C7 placed with laminoforaminotomy and palpation technique appears to be safe and efficacious. Excellent fixation can be achieved.

Assessment and management of dyspnoea.

The terms 'dyspnoea' or 'breathlessness' refer to an individual's subjective awareness of discomfort related to the act of breathing. Elevations in CO2 above normal levels have been shown to cause breathlessness although it is unlikely to be the sole cause of breathlessness in a clinical setting. Several studies suggest that supplemental O2 during exercise will diminish the sensation of breathlessness although not all work has confirmed this finding. Much about the role of gas exchange in dyspnogenesis remains controversial. Phrenic blockade can abolish dyspnoea in response to breath-holding, while work in quadriplegics suggests that the intercostal muscles are not involved. A separate and direct pathway from the respiratory centre to the sensory cortex has also be implicated. Threshold discrimination has established that patients with chronic airflow limitation (CAL) have a blunted response to the addition of resistive loads to breathing, while category scaling methods (e.g. the Borg scale) have added descriptive terms to these physiological measures. Questionnaires often appear limited by their subjectivity and lack of correlation with physiological changes, but remain a useful tool in the clinical setting. In regard to therapy of dyspnoea high fat diets have a theoretical advantage in the CAL group but are generally not well tolerated. Resistive training devices and exercise training in CAL have been widely researched but in general, measures of lung remain unaltered and many of the studies would suggest that they have little, if any, inpact on functional status. Beta-agonists have been widely shown to be useful in CAL patients, despite the fact that bronchodilatation is not always demonstrable. Anticholinergics have be shown to be effective bronchodilators, but whether there is an improvement in dyspnoea above that expected from improvement in lung function is unclear. Animal studies and work in normal individuals would suggest that methylxanthines have a theoretical role in CAL possibly by increasing diaphragmatic muscle strength and decaying fatigue, but toxicity and lack of clear benefit in this group suggest that they should not be used as monotherapy. There is little evidence to support the use of opioids in chronic CAL although their role in the acute dyspnoea of end-stage CAL remains defined. The use of benzodiazepines has also been disappointing. Bullectomy remains widely accepted in clinical practice. New techniques such as 'reduction surgery' for diffuse emphysema are showing promise, although still in need of further testing and validation.

An introduction to transoesophageal echocardiography: I. Basic principles.

PURPOSE: The purpose of this review is to introduce the uninitiated to transoesophageal echocardiography (TEE): how it works, and what it can do. Sufficient detail is provided to serve as a reference guide to anaesthetists already using TEE in clinical practice. SOURCE: A Medline search of English language literature up to and including August 1995 was conducted using the key words echocardiography and TEE. Reference echocardiography textbooks were also utilized in the preparation of this review. PRINCIPLE FINDINGS: All information available from TEE is derived from either cardiac imaging or analysis of blood flow velocity using various Doppler modes. To understand the diagnostic capabilities of TEE we review clinically useful views of the heart as well as modes of cardiac imaging. Sufficient basic physics is presented to allow proper use of adjustment features on the echocardiography machine so that cardiac imaging can be optimized. Available Doppler modes are explained along with an overview of their clinical applications. Figures illustrating clinically useful views obtainable with omniplane TEE are included along with colour prints demonstrating clinical applications of colour flow Doppler. CONCLUSION: TEE is becoming increasingly important in the management of cardiac patients for cardiac and non-cardiac surgery. An understanding of the capabilities of the technology as well as the underlying physics allows the anaesthetist to glean the most information from this valuable technique, both quantitatively and qualitatively.

Cardiopulmonary bypass for adult patients: a survey of equipment and techniques.

OBJECTIVES: The techniques and equipment used for cardiopulmonary bypass for adult cardiac surgery vary among institutions and may change over time. This study sought to document the changing patterns of practice. DESIGN: Voluntary survey of meeting participants. SETTING: 13th Annual San Diego Cardiothoracic Surgery Symposium (February 1993). PARTICIPANTS: There were 331 responses from perfusionists (79.5%), cardiac surgeons (11.2%), and anesthesiologists (6.3%). The majority of these participants were from institutions where more than 1,000 cardiac operations were performed annually. MEASUREMENTS AND MAIN RESULTS: It was found that 91.5% of the respondents used membrane oxygenators currently, compared with 5% in 1982 (as reported in a previous survey). Over 80% of the institutions surveyed used some type of perioperative cell-salvaging technique. Arterial line filters were used by 92% of the respondents compared with 64% in 1982. Also, 80% of the respondents were aware of the availability of leukocyte-depleting filters. CONCLUSIONS: The probable reasons for the increased utilization of membrane oxygenators and arterial line filters include less damage to the formed elements of blood, fewer gaseous microemboli, and better control of carbon dioxide elimination and oxygenation. The authors anticipate that future surveys will document increased use of leukocyte-depleting filters because of the literature implicating neutrophils as mediators of tissue destruction in various disease processes, including myocardial reperfusion injury.

Ulcerative eosinophilic stomatitis in three Cavalier King Charles spaniels.

Ulcerative eosinophilic stomatitis affecting three Cavalier King Charles spaniels is described. The lesions are similar in gross appearance to previously reported palatine eosinophilic granulomas, but histologically they lack granuloma formation. The cause of the lesions is not known. Treatment with corticosteroids led to the resolution of one case and partial resolution of a second. A third case resolved spontaneously without therapy.

Caesarean section and phaeochromocytoma resection in a patient with Von Hippel Lindau disease.

This report describes the anaesthetic management of a women with a term gestation, Von Hippel Lindau disease (VHLD), and a phaeochromocytoma, scheduled for a combined phaeochromocytoma resection and Caesarean section. Von Hippel Lindau disease is characterized by diffuse haemangioblastomas of the central nervous system (CNS) and viscera. It is also associated with phaeochromocytomas and renal cell carcinomas. Patients frequently have asymptomatic spinal cord and intracranial pathology. The patient and her fetus presented a challenge because of the anaesthetic restrictions imposed by VHLD, and her pregnancy. She was also at risk of developing malignant hypertension from the phaeochromocytoma. The patient was not a candidate for regional anaesthesia because of the possibility of spinal cord haemangioblastomas. She had received adrenergic blockade with phentolamine (total 30 mg a day) and propranolol (total 40 mg a day) since the 27th wk of gestation in order to control hypertension secondary to the phaeochromocytoma. General anaesthesia was administered with aggressive management of hypertension with adrenergic blockers (labetalol 1.0 mg.kg-1 and esmolol 0.75 mg.kg-1) and sodium nitroprusside 1.5 micrograms.kg-1 (total). Before delivery of the baby, opioids, which could have resulted in a fetus with CNS depression, were avoided. After delivery, opioids (sufentanil 0.4 microgram.kg-1 x hr-1) were used to limit the use of inhalational anaesthesia which may contribute to uterine atony. Postoperative pain was managed with an intravenous narcotic infusion. Both patients had uneventful postoperative courses.

The P3a wave of the auditory event-related potential reveals registration of pitch change during sufentanil anesthesia for cardiac surgery.

BACKGROUND: The N1 and P3 waves of the auditory event-related potential provide information on consciousness and cortical function. The N1 wave is reduced during states of low vigilance. The P3 wave occurs only for stimuli that somehow capture the subject's attention. There are two types of P3:P3a and P3b. The P3a predominates frontally and probably occurs when the subject simply notices the stimulus. The P3b predominates parietally and indicates conscious awareness of the evoking stimulus. The N1 and P3 were recorded in 12 patients during cardiac surgery under sufentanil anesthesia to search for unintentional awareness. The study was limited to the period before cardiopulmonary bypass. METHODS: After premedication with diazepam, morphine, and scopolamine, sufentanil was used for induction (mean dose, 7.9 micrograms/kg) and maintenance (4 micrograms/kg) of anesthesia. No other anesthetics were administered. Recordings were obtained before induction, during induction after loss of consciousness, after tracheal intubation before incision, and before cardiopulmonary bypass. RESULTS: The N1 was attenuated significantly by sufentanil but was not abolished. The P3b occurred only during preinduction. There was no P3 during induction. There was a P3a during postintubation and precardiopulmonary bypass. CONCLUSIONS: The attenuation of N1 from induction onward reflects a decrease in the level of arousal caused by sufentanil. A P3a during postintubation and precardiopulmonary bypass indicates that pitch discrimination at the cortical level occurs but does not prove that conscious awareness has occurred. Whether or not the P3a reflects the regaining of consciousness is not known.