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Biomedical subjects

P Scanlon

Publications and source records attributed to P Scanlon.

At least 19 recordsLinked to original sources

Grading and disease management in national screening for diabetic retinopathy in England and Wales.

AIMS: A National Screening Programme for diabetic eye disease in the UK is in development. We propose a grading and early disease management protocol to detect sight-threatening diabetic retinopathy and any retinopathy, which will allow precise quality assurance at all steps while minimizing false-positive referral to the hospital eye service. METHODS: Expert panel structured discussions between 2000 and 2002 with review of existing evidence and grading classifications. PROPOSALS: Principles of the protocol include: separate grading of retinopathy and maculopathy, minimum number of steps, compatible with central monitoring, expandable for established more complex systems and for research, no lesion counting, no 'questionable' lesions, attempt to detect focal exudative, diffuse and ischaemic maculopathy and fast track referral from primary or secondary graders. Sight-threatening diabetic retinopathy is defined as: preproliferative retinopathy or worse, sight-threatening maculopathy and/or the presence of photocoagulation. In the centrally reported minimum data set retinopathy is graded into four levels: none (R0), background (R1), preproliferative (R2), proliferative (R3). Maculopathy and photocoagulation are graded as absent (M0, P0) or present (M1, P1). DISCUSSION: The protocol developed by the Diabetic Retinopathy Grading and Disease Management Working Party represents a new consensus upon which national guidelines can be based leading to the introduction of quality-assured screening for people with diabetes.

Clinical Protocols↗

Potentiation of vincristine toxicity by itraconazole in children with lymphoid malignancies.

UNLABELLED: Eight consecutive paediatric patients with acute lymphoblastic leukaemia (ALL) (n = 7) and T-cell non-Hodgkin's lymphoma (NHL) (n = 1) presenting within a 5-wk interval were started on a standard induction protocol which included weekly treatment with vincristine for 4 wk. Itraconazole was commenced as antifungal prophylaxis, 1-21 d after the first injection of vincristine. Within 2 to 4 wk, enhanced vincristine neurotoxicity was noted in all patients, abdominal cramps and constipation occurred most frequently, and one patient developed a bowel perforation associated with paralytic ileus. Hyponatraemia associated with SIADH was observed in three patients and four patients developed seizures. An additional patient with B cell NHL developed seizures 5 d after an injection of vincristine. Recovery was complete in all patients and ranged from 2 d to 15 wk. CONCLUSION: The extent and consistency of adverse effects documented in this study support the recommendation that concurrent administration of vincristine and itraconazole should be avoided.

Adolescent↗

Universal vs. risk factor-based screening for gestational diabetes mellitus: detection rates, gestation at diagnosis and outcome.

AIMS: Gestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcome. Screening for GDM is therefore recommended but the best screening method remains controversial. This prospective, randomized study compared a risk factor-based screening programme with a universally based one. METHODS: Subjects were randomized at booking to one of two groups: the risk factor group had a 3-h 100-g oral glucose tolerance test (OGTT) at 32 weeks if any risk factor for GDM was present; the universal group had a 50-g glucose challenge test performed and if their plasma glucose at 1 h was > or = 7.8 mmol/l, a formal 3-h 100-g OGTT was then performed. RESULTS: Universal screening detected a prevalence of GDM of 2.7%, significantly more than the 1.45% detected in the risk factor screened group (P<0.03). Universal screening facilitated earlier diagnosis than risk factor screening - mean gestation 30 +/- 2.6 weeks vs. 33 +/- 3.7 weeks (P<0.05). A higher rate of spontaneous vaginal delivery at term, and lower rates of macrosomia, Caesarean section, prematurity, pre-eclampsia and admission to neonatal intensive care unit were observed in the universally screened, early diagnosis group. CONCLUSIONS: Universal screening for GDM is superior to risk factor based screening-detecting more cases, facilitating early diagnosis and is associated with improved pregnancy outcome.

Blood Glucose↗

Lessons learned from the review of cardiac catheterization laboratories: a report from the Laboratory Survey Committee of the Society for Cardiac Angiography and Interventions.

The Laboratory Survey Committee of the Society for Cardiac Angiography and Interventions was created as a resource for physicians and administrators to provide comprehensive independent outside review services for cardiac catheterization laboratories. Since 1989, when the committee began its work, surveys of 23 catheterization laboratories have been completed. Our review of this experience identified several recurring problems among the laboratories. The purpose of this paper is to summarize our experience and highlight the lessons we learned in the hope that this information will benefit many other laboratories.

Cardiac Catheterization↗

Propofol or sevoflurane for laryngeal mask airway insertion.

PURPOSE: Sevoflurane is a volatile anesthetic agent, which combines rapid, smooth inhalational induction of anesthesia with rapid recovery, making it particularly suitable for day case anesthesia. The laryngeal mask airway is often also used in ambulatory anesthesia, with intravenous propofol being the agent of choice for its insertion. Our objective was to compare the conditions for laryngeal mask airway (LMA) insertion obtained by modified vital capacity breath sevoflurane inhalational induction of anesthesia with propofol intravenous induction. METHODS: Eighty-eight patients, aged 18-65 yr, ASA I-II, undergoing general anesthesia for elective surgery were randomized into two groups in a prospective, single-blind study. Patients in Group P (n=44) received 2.5 mg x kg(-1) propofol i.v. and in Group S (n=44) received sevoflurane 8% in nitrous oxide 50% and oxygen. Ventilation was not assisted. Laryngeal mask airway insertion was attempted at one minute intervals from loss of both verbal response and eyelash reflex, by an anesthesiologist unaware of the induction technique. Complications, such as coughing and head movement, were also noted at each attempt. RESULTS: Mean time to successful LMA insertion was 1.3 (1-3) min in P and 2.2 (1-3) min in S, P < 0.05. Eleven patients in Group P, (25%) required additional propofol compared with four (9%) in S, P < 0.05. Incidence of complications was similar in both groups and by 3 min, LMA was successfully inserted in all patients. CONCLUSION: Modified vital capacity breath inhalational induction with sevoflurane 8% is efficient for LMA insertion in most cases, but takes slightly longer than propofol.

Adolescent↗

Anticoagulant therapy of pregnant patients with prosthetic heart valves: rationale for a clinical trial of low molecular weight heparin.

The management of anticoagulant therapy for the prevention of thromboembolism from prosthetic heart valves in the pregnant patient is far from ideal and deserves more clinical research. Warfarin therapy given alone throughout pregnancy poses high risks to the fetus because it crosses the placental barrier. Heparin alone throughout pregnancy poses high risks to the mother, which might be lessened somewhat by more intensive therapeutic regimens and careful monitoring of the heparin level or anticoagulated state of the blood. Because of the major risk of embryopathy in the fetus during the first trimester and latter half of the third trimester, heparin therapy during those times has been recommended. In the opinion of some experts, high-risk cases may benefit from low-dose aspirin in addition to anticoagulant therapy. The fact that warfarin is contraindicated during pregnancy (according to the pharmaceutical company that markets it) poses some problems for the physician who prescribes it. For the above reason, alternative drugs are worthy of consideration and should be given clinical trials. Low molecular weight heparin has the potential for greatly reducing drug-related risk for the fetus while providing greater safety for the mother.

Anticoagulants↗

Identification of permanent hearing loss in children: are the targets for outcome measures attainable?

A collaborative nine-centre study was designed to follow the routes to identification of all children up to the age of seven years newly diagnosed with permanent hearing impairment (> or = 50 dB HL) during the period 1993-1994. Ages of identification were compared with the standards set by the National Deaf Children's Society (NDCS), ascertaining whether these targets could be achieved with current service provision. Of the 126 children identified, 104 had congenital sensorineural hearing loss: 19% were identified by the age of six months and 39% by their first year. These results fall short of the NDCS targets of 40% and 80%, respectively, and point to the need for modifications of current practice, such as the introduction of universal neonatal screening.

Audiometry, Pure-Tone↗

The effects of loading changes on intraoperative Doppler assessment of mitral regurgitation.

Anesthetic agents may significantly alter the patient's blood pressure, and thus affect the intraoperative assessment of mitral regurgitation. This study examined the impact of an increase in afterload on a variety of parameters thought to reflect the severity of mitral regurgitation, and related them to changes in hemodynamic parameters. Twenty-four patients with mitral regurgitation undergoing cardiac surgery were studied. Following the induction of anesthesia, color-flow mapping of the entire left atrium was performed, and pulmonary vein flow was then measured. Phenylephrine was administered to increase the patients' blood pressures to their preoperative values, and the assessment was repeated. Regurgitant jet area increased 56% (482 +/- 405 v 750 +/- 440 mm2 P < 0.001), and there were significant reductions in systolic pulmonary venous velocity (0.33 +/- 0.17 v 0.18 +/- .31 m/s P < .01) with increases in diastolic flow (0.43 +/- 12 v 0.58 +/- 0.18 m/s P < .001). These changes in pulmonary venous flow were not related to the changes in the driving force across the incompetent mitral valve. Also, an additional six patients developed systolic flow reversal after phenylephrine administration. Intraoperative hemodynamic variations can significantly alter the apparent severity of mitral regurgitation, and this factor must be considered during decision making.

Adult↗

Patient response to laryngeal mask insertion after induction of anaesthesia with propofol or thiopentone.

The response to insertion of the laryngeal mask airway (LMA) following either propofol 2.5 mg.kg-1 or thiopentone 5 mg.kg-1 was assessed in two groups of patients. The purpose of the study was to ascertain which of these two induction agents provided the better conditions for insertion of the LMA. Anaesthesia was induced by propofol in 35 patients and by thiopentone in 37. Following induction, ventilation was assisted for two minutes using 50% oxygen and nitrous oxide and 2% isoflurane, before insertion of the LMA. The presence of gagging, coughing, laryngospasm and movement was noted and graded. Thiopentone was associated with an adverse response in 76% of patients, compared with propofol in 26% (P < 0.01). Gagging, laryngospasm and head movement were more common using thiopentone (P < 0.01, P < 0.05 and P < 0.05 respectively) and in 11% (P < 0.05) of the thiopentone group insertion of the LMA was impossible due to inadequate relaxation. We conclude that, using these doses, propofol is superior to thiopentone as an induction agent for insertion of the laryngeal mask airway.

Adult↗

Cardiovascular effects of lightning strikes.

OBJECTIVES: The purpose of this study was to investigate the effects of lightning strikes on the cardiovascular system. BACKGROUND: A lightning strike can attack its victims in one of three ways: direct hit, splash or ground strike. The cardiovascular system can be affected directly by mechanical or electrical trauma during a direct hit or can be indirectly affected through effects on the total body with extensive catecholamine release or autonomic stimulation. Reported effects include hypertension, tachycardia, nonspecific electrocardiographic (ECG) changes including prolongation of the corrected QT (QTc) interval, transient T wave inversion and myocardial necrosis with creatine kinase-MB (CK-MB) fraction release. METHODS: Nineteen victims from five separate lightning strikes were studied over a 2-month period. Each patient was evaluated by serial ECG, CK-MB determinations and echocardiography. RESULTS: The early (0 to 72 h) effects of lightning were demonstrated on the ECG by ST segment elevation consistent with acute current of injury, prolonged QTc interval with direct hits and nonspecific ST and T wave changes. On echocardiography, segmental or global ventricular dysfunction was seen, and pericardial effusion was also detected. During the intermediate (3- to 14-day) period, new and often marked ECG changes consistent with pericarditis or ischemia were seen. No new echocardiographic changes were detected, however, and the early abnormalities including severe left ventricular dysfunction with cardiogenic shock have reversed. The late (1 to 12 months) period revealed only one patient with long-term sequelae (recurrent pericarditis that persisted for 5 months). CONCLUSIONS: Unless both entrance and exit sites are limited to the lower limbs, direct and splash lightning strikes cause myocardial damage as assessed by abnormal serum enzyme determinations or abnormal echocardiographic findings. Only direct hits resulted in echocardiographic abnormalities or a prolonged QTc interval. The degree of myocardial injury can be severe with left and right ventricular ejection fraction < 15% and can be reversible.

Adult↗

Intraoperative detection of patent foramen ovale by transesophageal echocardiography.

This study reports the intraoperative use of contrast and Doppler echocardiography techniques to diagnose patent foramen ovale (PFO). Fifty patients without known atrial septal defects undergoing elective cardiovascular surgery were studied. A 5-MHz esophageal echocardiographic probe was used to image the fossa ovalis (FO) and 10 ml agitated saline was injected into the right atrium during apnea. Echocardiographic contrast was then injected during end-inspiration at 20-cmH2O airway pressure. When opacification of the right atrium was complete, the airway pressure was released. During these maneuvers, color and pulsed-wave Doppler interrogation of the atrial septum were also performed. Right-to-left passage of saline contrast across the interatrial septum was seen in 11 of 50 patients (22%). Doppler echocardiography demonstrated a PFO in 2 patients without contrast evidence of shunting. Thus, the combination of contrast and Doppler echocardiography identified a 26% (13 of 50) prevalence of PFO, approximating the previously reported autopsy rate of 25%. These contrast and Doppler techniques may be useful in detecting patients at risk for paradoxical emboli and in identifying candidates for closure of the PFO.

Adult↗

An unusual complication of brachial plexus sheath cannulation.

A 20-gauge cannula placed via an interscalene approach in the left brachial plexus sheath of a healthy 18-yr-old male was used inadvertently for injection of 20 ml of antibiotic solution, despite clear labelling of the cannula and painful protest from the patient. The patient suffered no neurological sequelae. The treatment, possible causes and steps to avoid similar incidents are described.

Adolescent↗

Beneficial effects of dopamine combined with intravenous nitroglycerin on hemodynamics in patients with severe left ventricular failure.

Hemodynamic effects of dopamine and intravenous nitroglycerin alone, and in combination, were studied in 27 patients with severe left ventricular failure. Dopamine alone increased cardiac index from 1.8 to 2.5 l/min/m2 but also increased wedge pressure from 24 to 30 mm Hg and heart rate from 88 to 101 beats/min. Arterial oxygen saturation fell from 92% to 87% (p less than .001). Nitroglycerin alone had a lesser effect on cardiac index (1.8 to 2.2 l/min/m2) but decreased wedge pressure from 26 to 16 mm Hg and heart rate from 91 to 86 beats/min. Arterial oxygen saturation fell from 91% to 90% (NS). Combined dopamine and nitroglycerin administration resulted in optimal hemodynamics, with cardiac index of 2.9 l/min/m2, wedge pressure of 17 mm Hg, and heart rate of 96 beats/min. Arterial oxygen saturation remained low at 88% in spite of the reduction in left ventricular filling pressure, which probably reflects increased intrapulmonary right-to-left shunting coupled with increased pulmonary blood flow. These results suggest that the combination of dopamine with intravenous nitroglycerin should be considered for patients with severe left ventricular dysfunction who require temporary pharmacologic support.

Adult↗

Thyroid remnant ablation: questionable pursuit of an ill-defined goal.

Ablative therapy with I-131 in 30-mCi doses, directed to postsurgical remnants in patients with differentiated thyroid cancer, reduced visible I-131 uptake to zero or nearly zero in 81% of patients but did not protect against tumor recurrence in six of 69 patients who were followed for 2-5 yr. Recurrences developed within 5-37 mo. Effectiveness of 30-mCi doses of I-131 in producing ablation did not correlate with I-131 uptake by the thyroid remnant, surgeon's estimate of remnant size, or delivered dose to the remnant in rads, calculated using reasonable assumptions. These findings emphasize the difficulty of dosimetric measurements and calculations. The value of postsurgical ablative therapy in diminishing morbidity and mortality in patients with differentiated thyroid cancer has not yet been firmly established, and until this is done we advocate a conservative, economical approach to thyroid ablation with 30-mCi treatment doses of I-131 and 1-mCi neck-scanning doses to check on effectiveness of therapy.

Adenocarcinoma↗