Do-not-resuscitate decision: the attitudes of medical and non-medical students

OBJECTIVES

To study the attitudes of both medical and non-medical students towards the do-not-resuscitate (DNR) decision in a university in Hong Kong, and the factors affecting their attitudes.

METHODS

A questionnaire-based survey conducted in the campus of a university in Hong Kong. Preferences and priorities of participants on cardiopulmonary resuscitation in various situations and case scenarios, experience of death and dying, prior knowledge of DNR and basic demographic data were evaluated.

RESULTS

A total of 766 students participated in the study. There were statistically significant differences in their DNR decisions in various situations between medical and non-medical students, clinical and preclinical students, and between students who had previously experienced death and dying and those who had not. A prior knowledge of DNR significantly affected DNR decision, although 66.4% of non-medical students and 18.7% of medical students had never heard of DNR. 74% of participants from both medical and non-medical fields considered the patient's own wish as the most important factor that the healthcare team should consider when making DNR decisions. Family wishes might not be decisive on the choice of DNR.

CONCLUSIONS

Students in medical and non-medical fields held different views on DNR. A majority of participants considered the patient's own wish as most important in DNR decisions. Family wishes were considered less important than the patient's own wishes.

Total intravenous anaesthesia with propofol and remifentanil for elective neurosurgical procedures

BACKGROUND AND OBJECTIVES

This was a prospective audit to assess the incidence and characteristics of early postoperative complications in the recovery room in extubated patients after elective neurosurgical procedures using propofol and remifentanil-based total intravenous anaesthesia.

METHODS

Vital signs (temperature, conscious level, respiratory rate, oxygen saturation, pulse and blood pressure) and postoperative complications (shivering, nausea, vomiting and cardiorespiratory) were analysed in 145 adult patients over a 1-yr period.

RESULTS

The overall shivering, postoperative nausea and vomiting and postoperative hypertension (systolic blood pressure more than 25% of the preoperative value) incidences were 30.3%, 16.6% and 35.2%, respectively. Fifty-one percent of the patients had at least one of the above complications. The complication rates were found to be widely different among various types of neurosurgery. The surgical procedures were divided into five groups: supratentorial craniotomy, posterior fossa craniotomy, intracranial vascular procedures, transphenoidal hypophysectomy and extracranial procedures. Median extubation time was similar in all groups and patients were fully conscious with no hypoxia in the recovery room. The intracranial vascular group had the highest shivering and postoperative nausea and vomiting rates (58.8% and 29.4%, respectively). In the supratentorial craniotomy group, 46% of the patients had hypertension. The overall complication rate (presence of any complications) was highest in the supratentfial craniotomy (55.4%), posterior fossa craniotomy (75%) and intracranial vascular (76.5%) groups. Shivering and overall complication rate was significantly related to the anaesthetic time (P<or=0.001 and 0.02, respectively).

CONCLUSIONS

Despite the potential advantages of total intravenous anaesthesia in titratability, rapid return of consciousness and reduced respiratory complications, making it suitable for planned extubation at the end of neurosurgery, the postoperative complications of shivering, postoperative nausea and vomiting and hypertension were still high.

Large venous air embolism in the sitting position despite monitoring with transoesophageal echocardiography

A 49-year-old male with neurofibromatosis type II was scheduled for posterior fossa craniotomy and excision of a right acoustic neuroma and placement of an auditory brainstem implant in the sitting position. Intra-operatively, the patient was monitored with transoesophageal echocardiography which detected two major episodes of venous air embolism. Despite immediate treatment the patient's gas exchange progressively worsened during surgery and a chest X-ray showed extensive bilateral pulmonary infiltrates. The patient developed acute respiratory distress syndrome and required inotropic support in the intensive care unit. Although transoesophageal echocardiography allowed rapid detection of venous air embolism, there was no evidence of therapeutic benefit.

Detecting synaptic connections in the medial nucleus of the trapezoid body using calcium imaging

The study of synaptic transmission in brain slices generally entails the patch-clamping of postsynaptic neurones and stimulation of identified presynaptic axons using a remote electrical stimulating electrode. Although patch recording from postsynaptic neurones is routine, many presynaptic axons take tortuous turns and are severed in the slicing procedure, blocking propagation of the action potential to the synaptic terminal and preventing synaptic stimulation. Here we demonstrate a method of using calcium imaging to select postsynaptic cells with functional synaptic inputs prior to patch-clamp recording. We have used this method for exploring transmission in the auditory brainstem at the medial nucleus of the trapezoid body neurones, which are innervated by axons from the contralateral cochlear nucleus. Brainstem slices were briefly loaded with the calcium indicator fura-2 AM and stimulated with an electrode placed on the midline. Electrical stimulation caused a rise in intracellular calcium concentration in those postsynaptic neurones with active synaptic connections. Since <10% of the medial nucleus of the trapezoid body neurones retain viable synaptic inputs following the slicing procedure, preselecting those cells with active synapses dramatically increased our recording success. This detection method will greatly ease the study of synaptic responses in brain areas where suprathreshold synaptic inputs occur but connectivity is sparse.