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Biomedical subjects

D Elmqvist

Publications and source records attributed to D Elmqvist.

At least 37 records · Page 2Linked to original sources

Oxygen desaturation during sleep and exercise in patients with interstitial lung disease.

The relations between mean and maximum fall in arterial oxygen saturation (SaO2) during sleep, hypoxaemia during moderate and maximum exercise, and lung mechanics were studied in 16 patients with interstitial lung disease. Mean and minimum SaO2 during sleep were significantly related to each other and to daytime oxygenation but not to lung mechanics. Although the maximum fall in SaO2 during sleep was similar to the fall during maximum exercise (a level seldom achieved during normal daily activities), profound hypoxaemic episodes during sleep were rare and brief and therefore contributed little to the mean SaO2. The fall in mean SaO2 during sleep was not significant and was considerably less than during moderate exercise (average 0.5 v an estimated 4.5%, p less than 0.05). It is therefore concluded that in patients with interstitial lung disease oxygen desaturation during sleep is mild and less severe than hypoxaemia during exercise.

Humans↗

Sleep in the surgical intensive care unit: continuous polygraphic recording of sleep in nine patients receiving postoperative care.

Sleep was studied in nine patients for two to four days after major non-cardiac surgery by continuous polygraphic recording of electroencephalogram, electrooculogram, and electromyogram. Presumed optimal conditions for sleep were provided by a concerted effort by staff to offer constant pain relief and reduce environmental disturbance to a minimum. All patients were severely deprived of sleep compared with normal. The mean cumulative sleep time (stage 1 excluded) for the first two nights, daytime sleep included, was less than two hours a night. Stages 3 and 4 and rapid eye movement sleep were severely or completely suppressed. The sustained wakefulness could be attributed to pain and environmental disturbance to only minor degree. Sleep time as estimated by nursing staff was often grossly misjudged and consistently overestimated when compared with the parallel polygraphic recording. The grossly abnormal sleep pattern observed in these patients may suggest some fundamental disarrangement of the sleep-wake regulating mechanism.

Adult↗

Pressures recorded in ulnar neuropathy.

The pressure between the ulnar nerve and the arcade bridging the two heads of the flexor carpi ulnaris muscle was recorded peroperatively in ten patients with electrophysiologically confirmed ulnar neuropathy at the elbow. At rest, with the elbow extended, pressures ranged from 0 to 19 mm Hg but increased in flexion and during isometric contraction of the flexor carpi ulnaris muscle to maximal values above 200 mm Hg.

Adult↗

Nerve lesions after total hip replacement.

In a prospective study 50 extremities in 46 patients with total hip replacement (THR) were examined clinically and with EMG preoperatively and 4 weeks postoperatively. Four patients with normal preoperative findings had electromyographical evidence of nerve lesions postoperatively and three of these had clinical symptoms; one patient had no clinical symptoms. Ten patients with normal pre- and postoperative findings were re-examined 1 year after the operation and still found to be normal. In 150 records of patients with THR reviewed retrospectively, only one doubtful case of nerve lesions was found.

Aged↗

Transcutaneous CO2 monitoring and disordered breathing during sleep.

A new device for non-invasive monitoring of PCO2, the Hewlett Packard cutaneous capnometer, was studied. Seven patients with disordered breathing, three with sleep apnoea syndrome, and four with chronic respiratory insufficiency, underwent polygraphic sleep recording including non-invasive measurement of oxygen saturation and transcutaneous CO2 pressure (PtcCO2). Two of the apnoea patients showed a modest increase in PtcCO2 with sleep. The patients with respiratory insufficiency showed larger increase in PtcCO2 and more profound hypoxemia during sleep. When the patients with respiratory insufficiency received oxygen (0.3-0.5 l/min) via nasal prongs, the sleep induced hypoxemia almost vanished but their PtcoCO2 increased. Nocturnal hypoventilation probably increased the effectiveness of the low oxygen supply, thus counteracting hypoxemia during periods of hypoventilation. The capnometer was easy to apply and the patients felt no discomfort. It promises to be a useful method for detection of hypercapnia indicating hypoventilation in patients with disordered breathing.

Aged↗

Pressure and nerve lesion in the carpal tunnel.

In 16 patients, where the diagnosis carpal tunnel syndrome was electrophysiologically confirmed, the pressure between the median nerve and the carpal ligament was measured peroperatively. At rest the pressure was 18-64 mmHg, mean 31 mmHg. Passive volar and dorsal wrist flexion increased the pressure about three times. Isometric or isotonic maximal contractions of wrist and finger muscles, elicited by tetanic nerve stimulation increased the pressure to three to six times the resting value. These high pressures may be one of the causes of the nerve lesion in the carpal tunnel syndrome.

Adult↗

Sleep apnea syndrome caused by acromegalia and the treatment with a reduction plasty of the tongue. Case report.

Obstructive sleep apnea syndrome was every likely caused by an enlarged tongue in a 60-year-old man with acromegalia. The diagnosis was confirmed by polygraphic sleep recordings and by roentgenologic examination. The patient was treated with a tongue-reduction plasty which gave him good subjective relief and better sleep. A whole night polygraphic sleep recording showed a couple of hours of normal sleep without apneas or arousals. The last part of the night was, however, still disturbed by several apneas with concomitant arousals.

Acromegaly↗

Hemifacial spasm: electrophysiological findings and the therapeutic effect of facial nerve block.

Twenty patients with cryptogenic hemifacial spasm have been examined electrophysiologically and treated with blockade of the facial nerve with phenol injections after localization of the nerve by electrical stimulation. The electrophysiological findings suggested a central origin of the spasms. The phenol injections abolished the spasms, but they recurred in most patients after 6 to 12 months. A few patients appeared to get permanent relief after one or more phenol injections. We used phenol blockade of the facial nerve as our first therapeutic treatment of choice in patients with distressing hemifacial spasm because it is a safe, simple, and repeatable procedure.

Adult↗

Sleep apnea syndrome--an alternative treatment to tracheostomy.

Two patients with obstructive sleep apnea syndrome had polygraphic recordings demonstrated upper airway obstruction and sleep with extremely short sleep latency, severely disturbed nightsleep resulting in sleep deprivation, and excessive daytime sleepiness. Radiological investigation showed the upper airway obstruction to be caused by the tongue falling back occluding the pharynx. Nasopharyngeal intubation relieved the symptoms. The patients were trained to perform this treatment themselves every night, demonstrating that this treatment is an attractive alternative to the conventional tracheotomy.

Disorders of Excessive Somnolence↗

Cardiovascular and neurological function in elderly patients sustaining a fracture of the neck of the femur.

Cardiac and neurological functions were evaluated at the time of operation in 81 randomly selected elderly patients who had sustained a fracture of the neck of the femur. Although only one-fifth of the patients had clinical signs of senile dementia or cerebrovascular disease on admission to hospital, more than half had seriously abnormal EEGs including 12 of the 15 patients who died within six months. ECGs before operation showed that patients with signs of arrhythmia or previous myocardial infarction had a much lower survival rate than those with normal or other pathological ECG signs. Nerve conduction velocity findings proved inconclusive when correlated with survival or return home. Routine EEG and ECG examinations are of value in detecting underlying dysfunctions which may not be observable clinically on admission but are important prognostic indicators for survival or return home, and may be implicated as causative factors of fracture in the elderly.

Aged↗

Acetylcholine receptor protein. Neuromuscular transmission in immunized rabbits.

Rabbits injected with purified acetylcholine (ACh) receptor protein produce antibodies against the receptor and develop generalized muscle weakness. The compound muscle action potentials show a decremental fall in amplitude with repetitive nerve stimulation. Both the weakness and the decrement is counteracted by reversible cholinesterase inhibitors. Intracellular recordings from muscle endplates show that the amplitude of the miniature end-plate potentials is considerably reduced. A reduced binding of neurotoxin to muscles from immunized rabbits was observed. Nerve impulses release a normal number of ACh packages (quanta) from the motor nerve terminals. The muscle weakness in immunized rabbits thus has the same features as the muscle weakness in myasthenia gravis and may be a good animal model of myasthenia gravis.

Acetylcholine↗

Focal reflex epilepsy with myoclonus; electrophysiological investigation and therapeutic implications.

A middle-aged man suffering from myoclonic jerks of the right arm and leg and occasional grand mal seizures was investigated electrophysiologically. The EEG showed a left central spike focus which could be activated by any stimulus which distorted the biceps, triceps or brachioradialis muscles but skin stimulation was ineffective. Electrical nerve stimulation subthreshold to the alpha motoneurone fibres evoked cortical spikes and myoclonic jerks. The evidence supports the hypothesis that the myoclonus was triggered by muscle spindle afferent fibres (Ia) which projected to an epileptogenic focus in the sensori-motor area. A marked improvement of symptoms was achieved by a combination of baclophen and dipropylacetate.

Animals↗

Correlation between single fibre EMG jitter and endplate potentials studied in mild experimental botulinum poisoning.

To study the correlation between single fibre EMG jitter and endplate potential amplitude we examined neuromuscular transmission in rats paralysed with botulinum toxin type A with single fibre EMG (SFEMG) in vivo and with intracellular microelectrode techniques in vitro. In muscles that were not completely paralysed SFEMG showed an increased neuromuscular jitter on nerve stimulation and in these muscles endplate potentials were of reduced amplitude. When the nerve stimulation frequency increased the jitter decreased. Intravenous injection of drugs that increase the acetylcholine release and endplate potential amplitude markedly reduced the jitter and the frequency dependence disappeared.

Action Potentials↗