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Biomedical subjects

J W Watt

Publications and source records attributed to J W Watt.

At least 37 records · Page 2Linked to original sources
PubMed1996

Intravenous salbutamol treatment for penile erection arising during cystoscopy of cervical spinal cord injury patients.

Two patients with long-standing tetraplegia after spinal cord injury developed reflex penile erection in the operation theatre. One had not received any anaesthesia, and penile erection occurred after introduction of the cystoscope into the urethra, and also autonomic dysreflexia. Intravenous salbutamol, in a dose of 10 micrograms, produced immediate and persistent penile detumescence and salbutamol-induced fall in blood pressure was of therapeutic value. In the second patient, penile erection occurred during general anaesthesia prior to cystoscopy. Immediate and persistent penile detumescence was achieved with intravenous salbutamol 20 micrograms. There was transient fall of blood pressure which responded to intravenous infusion of 0.9% sodium chloride. Salbutamol-induced fall in blood pressure is of therapeutic value in those spinal cord injury patients who develop, in addition to penile erection, autonomic dysreflexia precipitated by urethral instrumentation, or bladder distension with the irrigating fluid. Intravenous salbutamol is preferable to intra-cavernosal phenylephrine, noradrenaline, metaraminol, and epinephrine, or intravenous ephedrine which are contraindicated in patients with hypertension.

Adrenergic beta-Antagonists↗
PubMed1996

Total i.v. anaesthesia for transcranial magnetic evoked potential spinal cord monitoring.

Continuous intraoperative monitoring of transcranial magnetic motor evoked potentials (TcMMEP) can warn the surgeon of motor tract damage more effectively than somatosensory evoked potentials. As a non-invasive technique it is especially useful during post-traumatic internal fixation and is applicable whatever the level of the spinal cord at risk. Inhalation and many i.v. anaesthetics block the single pulse TcMMEP but a total i.v. anaesthetic regimen based on methohexitone, alfentanil and ketamine was effective in seven patients undergoing post-traumatic internal fixation. Consistent TcMMEP of 100-1000 mcV were obtained in all patients, with a latency change of only 2 ms above preoperative values. Good cardiovascular stability was maintained during operation.

Adult↗
PubMed1996

Epidural morphine for postherpetic neuralgia.

Eleven patients with established postherpetic neuralgia, unresponsive to antidepressant therapy, entered this single-blind, placebo-controlled study to assess the effectiveness of epidural morphine in the control of the pain of postherpetic neuralgia. Two patients obtained a reduction in pain of greater than 50% following morphine 0.5 mg. The duration of this pain relief was 36 h in one patient and 72 h in the other. Repeated doses, however, were ineffective in one patient and resulted in intolerable side effects in the other. The other six patients who received morphine developed opioid-related side effects without pain relief. Three patients did not receive morphine as they gained significant, long-lasting pain relief from placebo. Two retained that benefit for more than 6 months. Epidural morphine is more likely to produce side effects than pain relief when administered to patients with postherpetic neuralgia.

Aged↗
PubMed1996

The paradox of the StatCap carbon dioxide indicator. An experimental evaluation of rebreathing.

The StatCap semiquantitative carbon dioxide detector was evaluated in an experimental setting. The monitor underread at progressively higher concentrations of carbon dioxide. During simulated rebreathing, progressive increases in inspired carbon dioxide resulted in the StatCap readings decreasing. It is recommended that the StatCap be used with caution in circumstances where rebreathing may occur, for example, during manual ventilation with an Ayre's T-piece.

Carbon Dioxide↗
PubMed1996

Diaphragm pacing with a quadripolar phrenic nerve electrode: an international study.

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 +/- 1.0 years among children and 2.2 +/- 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0-4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication-free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94% of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.

Adult↗
PubMed1995

Does dead space ventilation always alleviate hypocapnia? Long-term ventilation with plain tracheostomy tubes.

Long-term tracheostomy-ventilated patients have better speech with a cuffless tracheostomy tube and a large tidal volume. Moderate day time hyperventilation from a pressure-limited ventilator is necessary in these patients to avoid hypoxia during sleep due to the variable insufflation leak. This study sought to confirm whether a dead space of 3 ml.kg-1 could help to provide normocapnic hyperventilation during waking time without causing hypercapnia and hypoxaemia during sleep. Transcutaneous blood gas studies were performed on 11 patients with high tetraplegia undergoing pressure-limited pulmonary ventilation with room air. Recordings were made for 120 min each when awake and asleep, with and without dead space. The mean derived arterial PCO2 without the dead space was 2.95 kPa awake and 3.21 kPa asleep, whilst the corresponding tensions with dead space were 3.39 kPa and 3.79 kPa. These small increases associated with the dead space, both awake and asleep, were statistically significant. There was a statistically, though not clinically significant decrease in oxygen tension when the patients without dead space went to sleep. The fact that the carbon dioxide tension was higher during sleep when dead space was in situ indicates that, despite the insufflation leak in these patients, there is significant rebreathing back through the dead space. Amelioration of hypocapnia during waking and sleeping is achievable using a dead space extension in these patients.

Blood Gas Monitoring, Transcutaneous↗
PubMed1995

Association between trigeminal neuralgia and multiple sclerosis: role of magnetic resonance imaging.

Seven consecutive patients with multiple sclerosis and trigeminal neuralgia were investigated with MRI to determine the occurrence of a lesion which would account for the patients' pain. Two patients had bilateral symptoms. In the patients with unilateral trigeminal neuralgia vascular compression of the nerve by an artery at the root entry zone on the symptomatic side was confirmed in three patients and an epidermoid tumour distorting the nerve on the symptomatic side was identified in one patient. A demyelinating plaque was identified in only one patient, affecting the trigeminal nerve at the root entry zone at the pons. In those with bilateral symptoms neurovascular compression was identified on both sides in one patient and on one side only in the remaining patient. Microvascular decompression cured the pain in two patients with neurovascular compression. The variable aetiology of trigeminal neuralgia is stressed even in patients with coexistent neurological conditions such as multiple sclerosis, which can cause trigeminal neuralgia independent of other causes.

Adult↗
PubMed1994

A retrospective study of hyponatremia in tetraplegic/paraplegic patients with a review of the literature.

The aetiology of hyponatremia in tetraplegic patients is multifactorial and includes not only general factors such as the use of diuretics and the intravenous infusion of hypotonic fluids, but also certain mechanisms which operate in the spinal cord injured: decreased renal water excretion due to both intrarenal and arginine vasopressin dependent mechanisms (resetting of the osmostat), coupled with habitually increased fluid intake, and the ingestion of a low salt diet. Between 1984 and 1993 we treated 28 episodes of hyponatremia in 19 patients (males: 10; females: 9). Fourteen were tetraplegic and five paraplegic (thoracic lesion in four and lumbar lesion in one). Six patients were asymptomatic during seven episodes of hyponatremia which were detected during routine blood tests. Seven patients were suffering from an acute chest infection, three had an acute urinary tract infection, one had an infected ischial pressure sore and a 69 year old paraplegic patient had bronchopneumonia as well as sepsis from a gangrenous pressure sore in the supraanal region. The time interval between the onset of paralysis and occurrence of the first episode of hypnoatremia was less than a month in only four of the patients. The lowest plasma sodium level observed was less than 100 mmol/l in two, between 100 and 110 mmol/l in four, between 111 and 120 mmol/l in eight patients, and between 121 and 128 mmol/l in 14 cases. Six patients also had hypokalemia (K+ < 3 mmol/l). Only one patient had and elevated plasma creatinine (201 umol/l). Treatment of sepsis and fluid restriction were the mainstay of treatment with only two patients receiving hypertonic saline. All patients with underlying sepsis were treated with antibiotics, usually administered intravenously. The outcome was good in 26 of the 28 episodes. Two patients died: a 68 year old tetraplegic patient with consolidation of the left lung, cystadenocarcinoma of both ovaries and squamous cell carcinoma of the forehead who presented with generalised oedema, with a plasma sodium level of 118 mmol/l, and potassium of 2.4 mmol/l and who was treated with 2 N saline + potassium + frusemide; she died 1 day later. The only other death was that of a 78 year old female tetraplegic patient who 2 days after sustaining cervical trauma developed hyponatremia because of intravenous infusion of hypotonic fluids given at another hospital, presumably to correct hypotension. She recovered from hyponatremia with fluid restriction, but 3 days later she succumbed to bronchopneumonia and respiratory insufficiency. No patient developed central pontine myelinolysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1994

The effect of insufflation leaks upon ventilation. A quantified comparison of ventilators.

Some ventilator-dependent patients use uncuffed tracheostomy tubes, resulting in fluctuations in the minute volume of ventilation. Bedside measurement of ventilation is difficult because of the insufflation and exsufflation leaks. This laboratory study of five different ventilators measured the tidal volumes achieved with three insufflation leaks introduced in an increasing order of magnitude and at three levels of compliance. The largest leak reduced the peak inflation pressure from 26 to 14 cmH2O in two pressure-limited ventilators with a 35% loss of the initial tidal volume of 800 ml. The turbine-driven pressure-limited ventilator retained a peak pressure of 20.5 cmH2O and lost only 14% of the volume, whereas the volume ventilators lost 65% of the tidal volume. The loss of volume was 3% for every cmH2O decrease in airway pressure due to a leak, regardless of the ventilator or compliance. Using the Friedman test, the differences between the volume ventilators and the pressure ventilators were significant whilst the three pressure-limited ventilators did not perform significantly differently from each other.

Equipment Design↗
PubMed1994

The effect of insufflation leaks in long-term ventilation. Waking and sleeping transcutaneous gas tensions in ventilator-dependent patients with an uncuffed tracheostomy tube.

Transcutaneous blood gases were recorded for 60 min when awake and asleep in 10 ventilator-dependent patients with high tetraplegia who used a pressure-limited ventilator and uncuffed tracheostomy tube. The mean arterial oxygen tension awake was 16.0 kPa compared with 15.2 kPa when asleep; the mean arterial carbon dioxide tension awake was 3.2 kPa, compared with 3.9 kPa when asleep. The oxygen tensions in each patient during the awake and sleep states were not significantly different between the two states, but during sleep the carbon dioxide tension was significantly greater.

Adolescent↗
PubMed1992

Perceptual deprivation in the acute phase of spinal injury rehabilitation.

Patients in intensive care units are often reported to experience psychological disturbances which may be attributable to a number of well-researched causes. However, it is suggested that the total lack of proprioceptive and motor feedback after spinal trauma may be a significant factor in the genesis of these disturbances which are unique to this group of patients. All cases admitted to the Regional Spinal Injuries Centre in Southport from January 1987 through December 1990 were assessed (n = 187) and the conditions surrounding the occurrence of behavioural disturbances (n = 23, 12.3%) established. The level of interaction with relatives and significant others was established for all acute admissions, and low frequency was found to correlate significantly with the development of perceptual deprivation experiences. The effects of inadequate somatosensory input, lesion level, increasing age, and visitor variability for spinal patients is discussed and an algorithm presented to highlight the potential factors associated with aetiology and treatment of the problem. The implications of these findings for the future management of acute spinal trauma are discussed.

Adult↗
PubMed1986

The artificial ventilation of acute spinal cord damaged patients: a retrospective study of forty-four patients.

The case histories of the 44 ventilated spinal cord damaged patients who have been treated at the Mersey Regional Spinal Injuries Centre prior to 1985 were reviewed. Complications of ventilation were commoner in patients whose ventilation was initiated prior to transfer to the specialised centre. Inappropriate early management before or during transfer to the spinal injuries centre led to the need for ventilation in several cases. Spinal cord damaged patients should be transferred to a specialised comprehensive centre as soon as possible after injury so that the requirement for ventilation can be minimised, the incidence of cardiac and respiratory arrest reduced, optimal methods of ventilation and weaning employed and global emotional and educational support provided from the outset for the patient and his family.

Acute Disease↗
PubMed1985

Ventilation or dignified death for patients with high tetraplegia.

The case histories of the 37 patients of the Mersey Regional Spinal Injuries Centre who were artificially ventilated between 1968 and 1984 were reviewed. The patients and caring relatives were interviewed separately to determine their views. Of 21 patients who were still alive, 18 said that they would wish to be temporarily ventilated again if the need arose, two were undecided, and one said that she would wish to be allowed to die. Sixteen caring relatives said that they were glad that the decision to ventilate had been taken. Those who were not glad were all young mothers. The outcome from any combination of factors that existed before injury could not be predicted except that most patients over age 59 fared badly. Patients with spinal cord damage should be artificially ventilated if required, provided that this can be carried out well and that total emotional, educational, and physical support can be provided and maintained. Whether or not scarce resources should be deployed in this manner requires discussion.

Adolescent↗