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Biomedical subjects

I Smith

Publications and source records attributed to I Smith.

At least 181 records · Page 10Linked to original sources
PubMed1994

Evaluation of the Cerebro Trac 2500 for monitoring of cerebral function in the neonatal intensive care.

Assessment of brain function is important in predicting long term outcome in sick neonates thus stimulating increasing interest in methods of cerebral surveillance. A report using the Cerebro Trac 2500 in adult intensive care suggested this monitor may provide more information about ongoing cerebral activity than the Cerebral Function Monitor (CFM). Simultaneous recordings in a cross-section of the neonatal population were obtained with multichannel EEG monitor, CFM and Cerebro Trac. Both conventional EEG and CFM determined changes in sleep states and background activity. Seizures of greater than 30 seconds duration were detected by both analyzing monitors, although shorter duration transients were not apparent. Despite the apparent similarity in fixed filters in both CFM and Cerebro Trac, the Cerebro Trac seemed to filter out the lower frequencies that can predominate in the neonatal EEG. The Cerebro Trac did not confer any advantage over the CFM for neonatal cerebral surveillance.

Brain↗
PubMed1994

Use of ketorolac after lower abdominal surgery. Effect on analgesic requirement and surgical outcome.

BACKGROUND: Ketorolac is a nonsteroidal antiinflammatory agent with opioid-sparing properties. The effect of ketorolac on postoperative opioid analgesic requirement and surgical outcome was evaluated in 198 women after abdominal hysterectomy procedures using a double-blind protocol design. METHODS: Patients were randomly assigned to receive either 60 mg intravenous (2 ml) ketorolac, followed by 30 mg intravenously (in saline 20 ml) over 30 min every 6 h, or 2 ml intravenous saline, followed by saline 20 ml intravenously over 30 min every 6 h, for up to 72 h. The postoperative opioid analgesic requirement was assessed using a patient-controlled analgesia (PCA) device to self administer either morphine or meperidine. The authors also evaluated pain, sedation (or drowsiness), fatigue, quality of sleep, and postoperative side effects at 2-8-h intervals for up to 72 h after surgery. RESULTS: Ketorolac decreased the PCA opioid usage on the night of operation and during the first postoperative day. Ketorolac also improved the quality of sleep during the first night after surgery. Although ketorolac- (vs. saline-) treated patients had a significantly shorter time to passage of bowel gas (50 +/- 24 h vs. 61 +/- 25 h), there were no clinically significant differences in the times to oral intake, unassisted ambulation, or hospital discharge. There were also no differences in the overall incidence of side effects in the ketorolac- (vs. saline-) treated patients. However, the use of ketorolac with opioid PCA was associated with a reduced need for antiemetic therapy on the postsurgical ward. CONCLUSIONS: The authors conclude that the opioid-sparing effects of ketorolac contributed few clinically significant advantages after abdominal hysterectomy procedures.

Adult↗
PubMed1994

Monitored anesthesia care.

The use of sedative and analgesic adjuvants during local and regional anesthesia can improve patient comfort while optimizing intraoperative conditions and increasing the range of procedures that can be safely and comfortably performed. Similarly, these techniques may be applied to procedures in which local anesthetic agents are unnecessary, or in which their administration is impractical. Although local anesthetic-based techniques are frequently perceived as safer than general anesthesia, the use of potent sedative-hypnotic and analgesic drugs (especially when used together) may cause significant depression of respiratory function. The need for vigilant monitoring, supplemental oxygen administration, careful titration of sedative-analgesic medications, and facilities and equipment for resuscitation is no different than when general anesthesia is employed. The availability of agents with more specific actions, shorter half-life values, and fewer adverse side effects, combined with a better understanding of drug actions and interactions, as well as new administration techniques, should make MAC safer and even more acceptable to patients.

Ambulatory Surgical Procedures↗
PubMed1994

Mutation analysis of the phenylalanine hydroxylase gene using heteroduplex analysis with synthetic DNA constructs.

Using heteroduplex analysis generated with synthetic PCR-amplifiable DNA we have screened the PKU populations of southwest England and Wales, western Scotland, and southeast and central England for mutations in exons 3, 7 and 12 of the phenylalanine hydroxylase (PAH) gene. The technique characterized three mutations in exon 12, two in exon 3 and five in exon 7. Altogether over 370 PKU chromosomes were screened. In all geographical regions exon 12 mutations (R408W, IVS12nt1g- > a and Y414C) accounted for about 40% of mutant chromosomes. Exon 3 mutations (principally I65T) were found on between 9 and 12% of mutant alleles and exon 7 mutations accounted for a further 5-7%. Heteroduplex analysis is rapid, simple and safe and three constructs covering three exons can identify between 55 and 60% of mutations in various PKU populations of the UK.

DNA↗
PubMed1994

Treatment of phenylalanine hydroxylase deficiency.

In phenylalanine hydroxylase deficiency detected by screening treatment in early life, both age at start of treatment and phenylalanine control during treatment are the major determinants of eventual psychological status. The influence of phenylalanine control declines with age but executive performance is influenced by hyperphenylalaninaemia at all ages. In a few subjects neurological deterioration has been reported years after relaxing or stopping treatment. MRI changes in brain white matter are present in most subjects no longer on a strict diet. These changes are usually reversible and closely related to phenylalanine status at the time of investigation. Whether or not the changes point to a specific vulnerability of white matter remains uncertain, although MRI changes were particularly prominent in subjects with neurological disability and may be irreversible in such subjects. Policies on treatment have to take account of these findings.

Adult↗
PubMed1994

Intellectual development at 10 years in early treated congenital hypothyroidism.

Fifty nine children born between 1978 and 1981 with congenital hypothyroidism detected by neonatal screening were assessed at 10 years using the Wechsler intelligence scale for children, together with 59 matched classroom controls. Thirty one children with severe hypothyroidism who had pretreatment plasma thyroxine concentrations of 40 nmol/l or less had a mean (SD) full scale IQ score of 104.7 (15.1), compared with a mean (SD) score of 114.6 (16.3) for the 28 less severely affected children who had pretreatment thyroxine levels greater than 40 nmol/l, and mean (SD) scores of 114.5 (12.8) and 114.8 (13.8) respectively for the 31 and 28 control children. In the hypothyroid children the IQ scores at 10 years were closely related to the IQ scores at 5 years and at 3 years. It is concluded that the deficit in IQ score found at 3 and 5 years in children with severe hypothyroidism is still evident at the age of 10 years.

Child↗
PubMed1994

Long term non-invasive domiciliary assisted ventilation for respiratory failure following thoracoplasty.

BACKGROUND: Ventilatory failure is a well recognised complication of patients who have had a thoracoplasty for tuberculosis, but there are few data regarding the value of long term non-invasive assisted ventilation in this situation. METHODS: Thirty two patients who had had a thoracoplasty 20-46 years previously and who had developed respiratory failure were treated with nocturnal cuirass assisted ventilation or nasal positive pressure ventilation. Their survival and changes in arterial blood gases, nocturnal oximetry, and pulmonary function tests were assessed. RESULTS: The actuarial survival rates at one, three, five, and seven years after starting treatment were 91%, 74%, 64%, and 55%, respectively. Only seven of the 13 deaths were directly attributable to chronic respiratory or cardiac failure. The arterial PO2, PCO2, mean nocturnal oxygen saturation, vital capacity, and maximal inspiratory and expiratory pressures had all improved at the time of the initial post-treatment assessment (mean 12 days after starting treatment), but no subsequent improvements were seen after up to 48 months of follow up. Neither survival nor physiological improvements were correlated with the patients' age, the interval since thoracoplasty, or the pretreatment arterial blood gas tensions or results of pulmonary function tests. CONCLUSIONS: These results show that, even when ventilatory failure has developed, the prognosis with non-invasive assisted ventilation is good and the physiological abnormalities can be partially reversed. Patients who develop respiratory failure after a thoracoplasty should be considered for this type of long term domiciliary treatment.

Adult↗
PubMed1994

Comparison of transesophageal atrial pacing with anticholinergic drugs for the treatment of intraoperative bradycardia.

We compared the effectiveness of atropine, glycopyrrolate, and a transesophageal atrial pacing (TAP) stethoscope for treating intraoperative bradycardia in 64 unpremedicated patients receiving a standardized sufentanil/N2O/vecuronium anesthetic. Patients were allocated randomly to receive either atropine, 5 micrograms/kg (Group 1), glycopyrrolate, 2.5 micrograms/kg (Group 2), or transesophageal atrial pacing (Group 3) after the onset of bradycardia, defined as a heart rate of < or = 50 beats/min (or < or = 60 beats/min with concurrent hypotension). Bradycardia occurred in 15 patients of each treatment group. The time required for the heart rate to increase to > or = 70 beats/min was 270 (range 30-490), 270 (70-465), and 12 (2-30) s in Groups 1, 2, and 3, respectively. Although all patients in Group 3 responded to pacing at 150% of the threshold current, 10 patients in Group 1 and 8 patients in Group 2 required a second dose of anticholinergic medication before a heart rate response was observed. One patient in Group 2 required three doses, and another who did not respond even after four doses was treated with the TAP device. Bradycardia subsequently recurred in five patients in Group 1 and four patients in Group 2. Temporary recurrence of bradycardia occurred in seven patients in Group 3 due to outward migration of the pacing stethoscope. However, heart rates were more consistently maintained in paced patients. There were no significant differences in postoperative side effects between the three groups, or when compared with patients who did not receive treatment for bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Use of forced-air warming during and after outpatient arthroscopic surgery.

According to a two-phase protocol, 127 patients undergoing arthroscopic knee surgery were randomly assigned to receive intraoperative warming from a forced-air blanket (n = 69) or conventional warmed cotton blankets (n = 58). During the initial phase (Phase I), active warming was applied during the intraoperative period only, permitting double-blind assessment of postoperative events. In Phase II, warming was continued into the recovery area, which unblinded the assessment. Active warming raised skin temperature perioperatively, and reduced the decline in core temperature compared to the control group. Postoperatively, core temperature increased toward preoperative values at similar rates in both treatment groups, but was still lower in control patients after an hour in the postanesthesia care unit (PACU). Postoperative shivering occurred in 35% of all patients and was not prevented by either intraoperative or combined intraoperative and postoperative warming. However, significantly fewer actively warmed patients experienced prolonged postoperative shivering. The addition of postoperative warming appeared to provide little, if any, additional benefit. Despite the decreased duration of postoperative shivering in the actively warmed group, we were unable to demonstrate any reduction in the PACU stay.

Adult↗
PubMed1994

Propofol infusion during regional anesthesia: sedative, amnestic, and anxiolytic properties.

We examined the plasma concentrations and resultant clinical effects produced by four different propofol bolus infusion regimens in 98 healthy males undergoing elective urologic procedures under regional anesthesia. Patients were randomly assigned to one of four propofol dosage groups. In Groups 1-4, loading doses of propofol equal to 0.2, 0.4, 0.5, or 0.7 mg/kg intravenously, respectively, were followed by fixed-rate propofol infusions of 0.5, 1, 2, or 4 mg.kg-1.h-1, respectively, during the regional block procedure. Sedation (sleepiness) was assessed independently by the patient and a blinded observer using 100-mm visual analog scales. Intraoperative amnesia was assessed using picture recall. Sedation scores increased in a dose-dependent fashion (13 +/- 19, 21 +/- 19, 45 +/- 28, and 73 +/- 26 mm at 30 min in Groups 1-4, respectively). Within a given dosage group, sedation scores were stable during the maintenance infusion period. Mean plasma propofol concentrations increased with higher propofol infusion rates (0.16 +/- 0.3, 0.18 +/- 0.1, 0.47 +/- 0.2, and 1.1 +/- 0.8 microgram/mL at 30 min in Groups 1-4, respectively). However, significant variability was observed among individual patient sedation scores and plasma propofol concentrations. Anxiety scores decreased in all four propofol infusion groups during the maintenance period. Hemodynamic variables and hemoglobin oxygen saturation values were similar in all four treatment groups. Recovery from propofol's central effects was rapid after discontinuation of the propofol infusion, and the incidence of side effects was low. Recall of intraoperative events was more commonly observed in the lower-dosage groups (86%, 96%, 58%, and 13% of patients in Groups 1-4, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Comparison of tracheal extubation in patients deeply anesthetized with desflurane or isoflurane.

A randomized, single-blind study design was used to compare desflurane with isoflurane in 31 adults undergoing intraocular surgery to determine whether the lower blood:gas partition coefficient of desflurane would result in a more rapid emergence after endotracheal extubation of deeply anesthetized patients. A standardized general anesthetic technique was used, consisting of sufentanil, 0.25 microgram/kg, and propofol, 1.5 mg/kg, followed by either isoflurane (n = 15) or desflurane (n = 16) in an air/oxygen mixture. After the operation and reversal of residual neuromuscular block, spontaneous ventilation was reestablished and the patients' tracheas were extubated at equianesthetic concentrations of desflurane and isoflurane (i.e., approximately 1.4 times the minimum alveolar anesthetic concentration [MAC]). Spontaneous movements occurred 5.7 (+/- 2.4) and 8.7 min (+/- 3.1; P = 0.005) after extubation in the desflurane and isoflurane groups, respectively. Eye opening and orientation also occurred significantly earlier after desflurane compared to isoflurane. Patients receiving desflurane (versus isoflurane) were also able to be transferred from the operating room significantly earlier (10.4 +/- 3.7 vs 14.5 +/- 4.3 min, P = 0.01). Use of desflurane (versus isoflurane) was not associated with an increased incidence of coughing or airway irritation during the emergence period. However, use of desflurane did not significantly reduce the duration of the postanesthesia care unit (PACU) stay or alter later recovery events compared to isoflurane. In conclusion, the more rapid emergence would favor the use of desflurane when tracheal extubation during deep anesthesia is required.

Adult↗
PubMed1994

Ambulatory anesthesia: past, present, and future.

Ambulatory anesthesia has become recognized as an anesthetic subspecialty, with formal postgraduate training programs. With increasing clinical experience, it is possible to determine which patients will derive the greatest clinical benefit from ambulatory surgery. Further expansion of the specialty of ambulatory anesthesia and surgery is likely to occur in the near future. The rate of expansion of ambulatory anesthesia will probably vary from country to country, depending on local needs, the level and availability of ancillary home health-care services, and economic considerations. Many recently developed drugs have pharmacological profiles that make them ideally suited for use in the ambulatory setting. Although these new drugs are valuable additions to the anesthesiologist's armamentarium, their cost is obviously higher than the drugs they were designed to replace. Given the changing pattern of health-care reimbursement, it is incumbent upon all practitioners to carefully examine the impact of new drugs and techniques on the quality of ambulatory anesthesia. It is obvious that these more rapid and shorter-acting anesthetic, analgesic, and muscle relaxant drugs have facilitated the early recovery process, thereby allowing our surgical colleagues to perform more extensive surgical procedures on an ambulatory basis. Future studies of new drugs and techniques for ambulatory anesthesia need to focus not only on subjective improvements for the patient during the perioperative period, but also on the overall cost-effectiveness of the care provided. These studies must compare the increased cost of new treatments with the potential financial savings resulting from earlier hospital discharge, reduced consumption of supplemental drugs, and earlier return to work. Recent pharmacological and technological advances in anesthesia and surgery allow outpatients with complex medical problems to undergo a wide variety of diagnostic and surgical procedures on an ambulatory basis. Increasingly, anesthesia practitioners as well as pharmacy and therapeutic committees are demanding evidence that new drugs and medical devices are superior to existing products--that they work better, have fewer adverse effects, and enhance efficiency, thereby reducing healthcare costs. As new biomedical technology is introduced to facilitate the perioperative management of patients (e.g., computerized anesthesia information management systems), evidence that these systems enhance our ability to provide high-quality, cost-effective health care will assume greater importance. The challenge that all practitioners face is to provide high-quality ambulatory anesthesia care at a reduced cost.

Adult↗
PubMed1994

Anesthesia for electroconvulsive therapy: effects of propofol and methohexital on seizure activity and recovery.

The influence of methohexital and propofol on seizure activity and recovery profiles was assessed in a randomized, crossover study involving 13 adult outpatients undergoing electroconvulsive therapy (ECT). Arterial blood pressure, heart rate, hemoglobin oxygen saturation, and electroencephalogram (EEG) activity were monitored during the ECT procedure. After premedication with glycopyrrolate, 0.2 mg intravenously (i.v.), and labetalol 20-30 mg i.v. hypnosis was induced with a bolus injection of either methohexital or propofol, 0.75 mg/kg. Muscle paralysis was achieved by administering succinylcholine, 1.4 mg/kg i.v. Ventilation was assisted using a face mask while administering 100% oxygen. Thereafter, an electrical stimulus was administered and the length of the resulting motor and EEG seizures was measured. Mood level and cognitive function were assessed prior to induction of anesthesia and after ECT. A total of 72 treatment sessions were evaluated. Each patient underwent a minimum of four treatments and received both induction drugs equally. Although the use of propofol was associated with significantly shorter motor and EEG seizure durations (mean +/- SEM) compared with methohexital (34 +/- 1.6 s and 52 +/- 2.9 s vs 39 +/- 1.5 s and 61 +/- 3.0 s, respectively), this difference was not clinically significant because the durations exceeded 30 s in both groups. Although awakening times were similar, both hemodynamic stability and cognitive recovery were more favorable after propofol. Compared with methohexital, the use of propofol was associated with a clinically insignificant decrease in seizure duration. However, propofol was associated with improved hemodynamic stability and an earlier return of cognitive function after ECT.

Anesthesia↗
PubMed1994

The effect of three dentifrices and a dental gel on plaque formation: a six week clinical study.

A six week single-blind clinical study was conducted to compare the effect of three dentifrices and a dental gel on the formation of dental plaque. On the criterion of their baseline plaque scores, male and female adult subjects were allocated to groups by restricted randomisation. The subjects used their assigned dentifrice twice a day and were examined for the presence of plaque after three and six weeks use. The results showed that the dental gel significantly reduced plaque when compared with the three dentifrices. There was no significant difference among the dentifrices with regard to plaque formation.

Adolescent↗