[Perspectives of laser-assisted keratoplasty: current overview and first preliminary results with the picosecond infrared laser (λ = 3 µm)]. / Perspektiven der laserassistierten Keratoplastik: Eine aktuelle Übersicht und erste experimentelle Erfahrungen mit dem Pikosekundeninfrarotlaser (λ = 3 µm).

BACKGROUND: This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination. METHODS: The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions. RESULTS: A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue. CONCLUSION: The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.

Modified electrode placement must be recorded when performing 12-lead electrocardiograms.

BACKGROUND: Local observation has suggested that placing limb leads on the torso when recording the standard 12-lead resting electrocardiogram (ECG) has become commonplace. This non-standard modification has the important advantages of ease and speed of application, and in an emergency may be applied with minimal undressing. Limb movement artefact is also reduced. It is believed that ECGs obtained with torso electrodes are interchangeable with standard ECGs and any minor electrocardiographic variations do not affect diagnostic interpretation. STUDY DESIGN: The study compared 12-lead ECGs in 100 patients during routine electrocardiography, one being taken in the approved way and one taken with modified limb electrodes. RESULTS: It was found that the use of torso leads produced important amplitude and waveform changes associated with a more vertical and rightward shift of the QRS frontal axis, particularly in those with abnormal standard ECGs. Such changes generated important ECG abnormalities in 36% of patients with normal standard ECGs, suggesting "heart disease of electrocardiographic origin". In those with abnormal standard ECGs, moving the limb leads to the torso made eight possible myocardial infarcts appear and five inferior infarcts disappeared. Twelve others developed clinically important T wave or QRS frontal axis changes. CONCLUSIONS: It is vital that ECGs should be acquired in the standard way unless there are particular reasons for not doing so, and that any modification of electrode placement must be reported on the ECG itself. Marking the ECG "torso-positioned limb leads" or "non-standard" should alert the clinician to its limitations for clinical or investigative purposes, as any lead adaptation may modify the tracing and could result in misinterpretation.

Emergency drug availability for the cardiac arrest team: a national audit.

Cardiac arrest teams are called upon to deal with many different acute medical emergencies, including cardiac arrest. However, the drugs that are supplied for them to perform their role differs vastly from hospital to hospital. We have confirmed this in an audit of adult cardiac arrest teams from all the acute hospitals within Wales. The rational use of defibrillation and drugs during cardiopulmonary resuscitation has been standardised according to International guidelines, and there is no reason why resuscitation kits could not also be standardised. Further considerations of drug availability is needed for acute management of other collapsed patients without cardiac arrest, most commonly vaso-vagal syncope, anaphylaxis, hypoglycaemia, fits and respiratory arrest. Based upon recent recommendations from the project team of the Resuscitation Council (UK), augmented by other commonly needed drugs for first aid in the collapsed patient, we propose a reduced and simplified emergency drug list, employing a two box system covering immediate and most secondary requirements. A standardised format of drug kits for use by adult cardiac arrest teams could speed effective delivery of emergency care.

Patients with cardiac disease: considerations for the dental practitioner.

The provision of dental treatment under both local anaesthesia and sedation has an excellent safety record, although medical problems may occur. The high prevalence of cardiac disease in the population, particularly ischaemic heart disease, makes it the most common medical problem encountered in dental practice. Additionally, the increasing survival of children with congenital heart disease makes them a significant proportion of those attending for dental treatment. While most dental practitioners feel confident in performing cardio-pulmonary resuscitation, treating patients with co-existent cardio-vascular disease often causes concern over potential problems during treatment. This article aims to allay many of these fears by describing the commoner cardiac conditions and how they may affect dental treatment. It outlines prophylactic and remediable measures that may be taken to enable safe delivery of dental care.

Diabetic hypoglycaemia and the dental patient.

Hypoglycaemic attacks in patients with insulin-treated diabetes are unpleasant and inconvenient at best, but may constitute a medical emergency at their most severe. This article provides the dental practitioner with an insight into the physiological processes which occur during such attacks, with clues to the recognition of the signs of impending hypoglycaemia. Steps which may be taken to avoid hypoglycaemia with the various forms of treatment are then considered against a background of their suitability for use in dental practice.

Early warning signs of impending hypoglycaemia masked by post-extraction labial paraesthesia.

Temporary lingual and labial paraesthesia are not uncommon following the removal of mandibular third molar teeth. In patients with insulin-treated diabetes circum-oral paraesthesia is a common and important sign of impending hypoglycaemia. This report highlights the case of a 17-year-old girl with Type 1 (insulin-dependent) diabetes who, following the extraction of her four wisdom teeth, experienced minor circum-oral sensory disturbances. These effectively masked her early warning signs of impending hypoglycaemia which had hitherto allowed her to have very good glycaemic control. Trembling, sweating and loss of concentration became the new presenting symptom complex, which she found both disabling and worrying. Fortunately, within six months the paraesthesia had subsided and the patient was once again able to appreciate her usual warning symptom of impending hypoglycaemia.

Tumour presenting as a retrosternal abscess following median sternotomy.

A 73-year-old lady, who underwent coronary artery bypass grafting eight months previously, presented with rigors and chest pain. The upper sternum was tender, swollen and erythematous, suggesting a retrosternal abscess. Radiological investigation supported the clinical diagnosis. Local infections following median sternotomy are uncommon, most being early and superficial. Late infections are very uncommon, and should suggest alternative pathology. Following open surgical drainage, histology showed the mass to be a poorly differentiated adenocarcinoma. The primary tumour was never found.

Ocular purpura in a swimmer.

Swimming goggles are increasingly being worn by children during swimming lessons to protect their eyes, although reports of ocular damage associated with their use is becoming more common. We describe a new injury, 'purpura gogglorum', caused by overtight application of faulty goggles. Whilst no permanent harm to the eyes resulted in this case, other swimmers have sustained more serious ocular damage, including loss of sight, from goggle-associated injury.

The tight pants syndrome--a sporting variant.

Tight neoprene 'warm pants' are increasingly utilised by sportsmen to prevent muscular injury. However, they may impede venous flow from the legs. We describe a case of extensive proximal deep vein thrombosis with subsequent pulmonary embolism in a fit young man with previous hip trauma.

Side effects with amiodarone therapy.

Amiodarone hydrochloride is increasingly being used in the treatment of ventricular and supraventricular arrhythmias. Although a highly effective anti-arrhythmic agent, its use is restricted by the high incidence of side effects. To elucidate the value of monitoring serum level of both the parent drug and its active metabolite in predicting the occurrence of side effects, the investigators examined 109 patients from a register of patients treated with amiodarone for the prevalence of known side effects of the drug. The register contained over 90% of patients treated with amiodarone at the Leicester General Hospital during the period of the study. The findings suggest cutaneous side effects and abnormal thyroid function tests (without overt gland dysfunction) are more likely to occur with increasing duration of treatment and cumulative dosage. However, neither the serum amiodarone level nor the serum metabolite level had any predictive power for the occurrence of side effects. In view of this finding, it is recommended that close attention be paid to the continued clinical monitoring of side effects and that there is utility in measuring the serum amiodarone level in each patient to avoid the prescription of unnecessarily high doses. This is necessary not only to lessen the occurrence of cumulative dose-related side effects, but also because the variable but very long half-life of the drug leads to difficulties in relating spot drug levels to long-term effects.

Circadian variation in the frequency of onset of chest pain in acute myocardial infarction.

The time of onset of chest pain was studied prospectively in 1154 consecutive patients admitted to a coronary care unit with myocardial infarction during a five year period. Statistical analysis confirmed a previous finding in a retrospective study of a bimodal frequency distribution with peaks in the time of onset of chest pain between 2330 and 0030 hours and between 0630 and 0830 hours.