PEEP and CPAP

Positive end-expiratory pressure (PEEP) maintains airway pressure above atmospheric at the end of expiration, and may be used with mechanical ventilation or spontaneous breathing. CPAP, or continuous positive airway pressure, refers to spontaneous ventilation with a positive airway pressure being maintained throughout the whole respiratory cycle. PEEP/CPAP primarily improves oxygenation by increasing functional residual capacity, and may increase lung compliance and decrease the work of breathing. PEEP/CPAP may be applied using endotracheal tubes, nasal masks or prongs, or face masks or chambers to treat a wide range of adult and paediatric respiratory disorders. Complications associated with their use relate to the pressures applied and include pulmonary barotrauma, decreased cardiac output and raised intracranial pressure.

Radiology of fracture-dislocation of the cervical spine during delivery

Four infants with fracture-dislocation of the cervical spine after traumatic delivery are described. In one patient with tetraparesis and complete dislocation of the cervical spine, transection of the cord at C6 was shown at autopsy. Two patients had fractures through the superior cartilaginous plates of the vertebral body with anterior subluxation of the spine. A fourth patient had a vertical fracture through the body of C5 with tracheal compression secondary to anterior dislocation of the spine. With conservative therapy, these three patients had good clinical recovery with healing and remodeling of the fractured vertebrae.

The recovery of pre-ovulatory oocytes using a fixed schedule of ovulation induction and follicle aspiration

Thirty-two volunteer women, scheduled for laparoscopy, were subjected to a fixed regimen of ovulation induction and ovarian follicle aspiration, following manipulation of the previous menstrual cycle with oral contraceptive pills or norethisterone. This allowed the time of oocyte recovery to be planned several weeks in advance. The recovery rate of mature oocytes (loosely dispersed cumulus) in the patients who had their cycles adjusted with norethisterone was comparable to that in a group of women treated in an embryo-transfer programme who were being individually monitored, although there was evidence from cleavage rates and concentration of sex steroids in follicular fluid that further follicular maturation could have occurred. It is suggested that a modification of this schedule could provide an acceptable recovery rate of pre-ovulatory oocytes for research purposes, and possibly by simplifying the monitoring technique could be applicable to a wider range of patients seeking embryo transfer.

Towards safer transport of sick and injured children

A Paediatric Emergency Transport Service has been operating from the Paediatric Intensive Care Unit of the Royal Children's Hospital, Melbourne, for the last three years. The records of the first 158 patients evacuated have been analysed and are reported. Problems relating to the care of the airway and artificial airway have been the most common. The need for careful pre-transport resuscitation and stabilisation is emphasised. The educational role of a transport service both at the time of initial consultation and at the time of retrieval is stressed.

Death from a snake bite: associated with the supine hypotensive syndrome of pregnancy

A young pregnant woman, near term, died shortly after being bitten by an immature brown snake (genus Pseudonaja). Analysis of the bitten area suggested that the degree of envenomation was mild, and could not satisfactorily explain her rapid demise. It was concluded that the supine hypotensive syndrome of pregnancy was a contributing factor in her death.

A paediatric emergency transport service: one year's experience

A paediatric emergency transport service (PETS) has been developed in Melbourne to cater for the secondary evacuation of children beyond the neonatal period. A consultative and transport service is provided. Forty-six children were transported in the first year of operation and the details are now reported. It is believed that the service is fulfilling a hiatus in the delivery of emergency health care to regional centres and that it will reduce morbidity and mortality in this group of critically ill children.

Funnel-web spider (Atrax robustus) antivenom. 1. Preparation and laboratory testing

An antivenom to the Sydney Funnel-web Spider, Atrax robustus, developed in rabbits, passed exhaustive quality control studies and was subsequently tested in monkeys. It was shown to reverse the syndrome that follows envenomation in both a conscious unmonitored monkey and in two anaesthetised, monitored monkeys. This paper reports the results of these experiments. An autonomic crisis appears to be the major cause of mortality and morbidity in human victims and monkeys; this aspect of the syndrome is rapidly attenuated by the antivenom. We observed no ill-effects of antivenom.

Serpentine cauda equina nerve roots

Serpentine filling defects caused by redundant nerve roots were demonstrated myelographically in three patients with a nonionic, water-soluble contrast material. All patients had either total obstruction or severe stenosis of the subarachnoid space secondary to extradural lesions.

The period of nasotracheal intubation in acute epiglottitis

Experience during the last three years with nasotracheal intubation in children with acute epiglottitis indicates that a period of intubation of 8-12 hours after the institution of appropriate antibiotic therapy is satisfactory in most patients. Shortening the period of intubation should have benefits to the patient. A shorter period of intubation should provide less opportunity for complications to develop and allow earlier discharge.

Acute intracranial hypertension occurring during infusion of stable plasma protein solution

A case of traumatic cerebral oedema is reported in which the infusion of small volumes of stable plasma protein solution (SPPS) resulted in acute and massive increases in intracranial pressure. The batch of SPPS responsible was found to have high levels of prekallikrein activator which is thought to be the cause of the systemic hypotension previously described with plasma proteins solutions. A second batch of SPPS with low levels of prekallikrein activator generated much smaller increases in intracranial pressure. The mechanism of this phenomenon is discussed and a recommendation made for the cautious use of SPPS when intracranial hypertension is present or suspected.

Effects of Sydney funnel-web spider envenomation in monkeys, and their clinical implications

The effects of the venom of the male Sydney funnel-web spider were studied in closely monitored monkeys, and a number of new features were observed. Excessive catecholamine release was demonstrated and linked to the development of hypertension, arrhythmias, pulmonary oedema, hyperthermia, and metabolic acidosis. Acute intracranial hypertension was found, and may partly explain the central neurological manifestations. It is believed that a neurogenic basis for pulmonary oedema may sometimes exist. Survival after massive envenomation was achieved with the use of aggressive pharmacological denervation of the motor and autonomic nervous systems.

Local inactivation of funnel-web spider (Atrax robustus) venom by first-aid measures: potentially lifesaving part of treatment

Venom of the male Sydney funnel-web spider was injected subcutaneously into the limbs of monkeys (Macaca fascicularis), and the central movement of venom was delayed by first-aid treatment. This treatment consisted of the application of firm pressure over the site of injection and immobilization of the limb. It was found that quantities of venom as high as 2 mg were inactivated when the first-aid procedures were maintained for 24 hours. Over a six-hour period, 0.5 mg of venom could be inactivated. Since the amount of venom injected by the spider into a human victim is unlikely to exceed 0.2 mg, these findings have immediate application both to the first aid and to actual medical management of human victims.

New first-aid measures for envenomation: with special reference to bites by the Sydney funnel-web spider (Atrax robustus)

The advantages of the pressure/immobilization technique as the first-aid measure for envenomation are discussed. The use of arterial tourniquets is no longer recommended in the management of any type of envenomation in Australia.

Cerebral embolic disease: a complication of carotid aneurysms

Thrombus formation in large aneurysms is well recognized. However, thrombi in small aneurysms with subsequent embolization into intracranial vessels is infrequently identified or suspected. A series of cases in which this phenomenon has occurred is documented. Since many of these examples present embolic disease without suspicion of aneurysm, definitive diagnosis can only be accomplished by angiography. The importance of this study should be emphasized since embolic disease is usually assessed only by computed tomography which fails to delineate the embolic source.

Radiological evaluation of paragangliomas of the head and neck

Paragangliomas can be differentiated angiographically from most other tumors in the head and neck by their profuse vascularity; specific classification is based on their position and displacement of adjacent vessels. Subtraction usually aids in diagnosis. In most cases, bilateral carotid angiography should be performed, since the ipsilateral carotid artery may have to be ligated and an asymptomatic contralateral tumor may also be found during surgery. Studies of multiple vessels will often show an additional blood supply. Computed tomography can demonstrate the tumor's vascular nature and position and is valuable in follow-up after radiation therapy.

Chondrosarcoma of the spine

Involvement of the spine by chondrosarcoma is rare. Three recent cases involving the cervical with or without extension to the thoracic spine are reported. Detailed radiologic investigations to evaluate the extent of the disease are essential to management. Computerized axial tomography and angiography were performed in 1 case and were extremely helpful. Surgical resection of the lesion is the only currently effective method of treatment, but long-term survival figures are not good.

Spinal arachnoid cysts in children

Five cases of benign spinal arachnoid cysts in children are described with their clinical, neuroradiological, surgical and pathological findings. Intraspinal benign arachnoid cysts may be confidently diagnosed myelographically when there is complete or partial obstruction with multiple oily contrast/cerebrospinal fluid levels as in 3 cases in this series. The multiple fluid levels are probably produced by multiple cysts or a cyst loculated due to partial compression by arachnoid bands either related to the normal septum posticum, congenital or acquired adhesion rather than to trabeculations within the cyst. In this series, the origin of the cysts is considered to be congenital.