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Biomedical subjects

A J Macnab

Publications and source records attributed to A J Macnab.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Ruptured intracranial aneurysm presenting as cerebral infarction in a young child.

We describe a 15-month-old girl who presented with an acute hemiplegia. The sequence of events appears to have been clinically silent subarachnoid hemorrhage, vasospasm, infarction and a second lethal hemorrhage 3 months later. The old infarction was seen on computed tomography during her second illness. Autopsy confirmed the presence of a recent rupture of an intracranial aneurysm and old hemorrhage. In addition there was an unusual fibroblastic proliferation in the aneurysm wall. This case demonstrates that clinically silent subarachnoid hemorrhage, vasospasm and infarction can occur as complications of aneurysms, even in very young children.

Brain↗
PubMedDate not supplied

Critical incident stress intervention after loss of an air ambulance: two-year follow up.

OBJECTIVE: Following an air ambulance crash with five fatalities, critical incident stress debriefing (CISD) was provided for involved paramedics, physicians, and nurses. A study was conducted to evaluate the long-term effects of a critical incident with critical incident stress debriefing according to the Mitchell model. METHODS: Six months following the incident, empirically designed questionnaires were mailed to all transport paramedics and directly involved medical staff, and a random sample of both nurses from the dispatch/receiving institution and paramedics from around the province. Twenty-four months post-incident, all members of the transport paramedics completed the Impact of Events Scale and the General Health Questionnaires. RESULTS: There were no differences between groups on any scores, except for disturbed sleep patterns, bad dreams, and the need for personal counseling being greater among transport paramedics at one day. There was no correlation between how well the deceased individuals were known, amount of debriefing, and symptom severity. A trend was seen for those with pre-existing stress management routines to have less severe symptoms at six months (p = 0.07). At two years, 16% of transport paramedics still had significant abnormal behavior. CONCLUSIONS: CISD did not appear to affect the severity of stress symptoms, whereas having pre-existing stress management strategies may. These findings give justification for proceeding to a randomized, controlled trial of different levels of critical incident stress intervention.

Accidents, Aviation↗
PubMedDate not supplied

The cost-benefit of pulse-oximeter use in the prehospital environment.

INTRODUCTION: Pulse-oximetry has proven clinical value in Emergency Departments and Intensive Care Units. In the prehospital environment, oxygen is given routinely in many situations. It was hypothesized that the use of pulse oximeters in the prehospital setting would provide a measurable cost-benefit by reducing the amount of oxygen used. METHODS: This was a prospective study conducted at 12 ambulance stations (average transport times > 20 minutes). Standard care protocols and paramedic assessments were used to determine which patients received oxygen and the initial flow rate used. Pulse-oximetry measurements (SpO2) were then taken. If SpO2 fell below 92% or rose above 96% (except in patients with chest pain), oxygen (O2) flow rates were adjusted. Costs of oxygen use were calculated: volume that would have been used based on initial flow rate; and volume actually used based on actual flow rates and transport time. RESULTS: A total of 1,907 patients were recruited. Oximetry and complete data were obtained on 1,787 (94%). Of these, 1,329 (74%) received O2 by standard protocol: 389 (27.5%) had the O2 flow decreased; 52 had it discontinued. Eighty-seven patients (6%) not requiring O2 standard protocol were hypoxemic (SpO2 < 92%) by oximetry, and 71 patients (5%) receiving oxygen required flow rate increases. Overall, O2 consumption was reduced by 26% resulting in a cost-savings of $0.20/patient. Prehospital pulse-oximetry allows unnecessary or excessive oxygen therapy to be avoided in up to 55% of patients transported by ambulance and can help to identify suboptimally oxygenated patients (11%). CONCLUSIONS: Rationalizing the O2 administration using pulse-oximetry reduced O2 consumption. Other health care savings likely would result from a reduced incidence of suboptimal oxygenation. Oxygen cost-saving justifies oximeter purchase for each ambulance annually where patient volume exceeds 1,750, less frequently for lower call volumes, or in those services where the mean transport time is less than the 23 minute average noted in this study.

Ambulances↗
PubMedDate not supplied

The cost of family-oriented communication before air medical interfacility transport.

INTRODUCTION: Family-oriented communication with parents by transport teams eases the stress associated with transferring children to tertiary care. This study was conducted to determine the duration of family-oriented visits and whether the visit contributed significant cost to the mission. METHOD: Data collection was prospective and double-blind; questions were incorporated into another study. Subjects were infants or children requiring assisted ventilation and air transport to tertiary care. Time from completion of stabilization to departure and reasons for any delay were recorded. Cost of contact time longer than 20 minutes (total acceptable time for family visit and transfer to vehicle) was calculated at paramedic overtime at $0.82/minute and aircraft wait time at $200/hour if incurred. RESULTS: Forty-six patients were enrolled. In 16 cases (35%), time between completing stabilization and hospital departure exceeded 20 minutes, with "family visit" listed as the explanation. Nine of these visits incurred overtime, and two incurred aircraft wait costs. Total costs for providing communication visits more than 10 minutes long were $607 or approximately $13 per patient. CONCLUSION: The costs for visit time longer than 10 minutes are small compared with the documented benefits of family-oriented communication. However, transport personnel must be mindful of the potential to incur additional cost through overtime, aircraft wait time, or pilot replacement.

Air Ambulances↗
PubMedDate not supplied

Changes in pCO2 during air medical transport of children with closed head injuries.

OBJECTIVES: Because low partial pressure of carbon dioxide (pCO2) can be associated with posttraumatic cerebral ischemia, we conducted a study to determine whether the pCO2 level in ventilated children with closed head injuries transported by a trained team to tertiary care was optimally maintained during transport and determine whether hand-bagging or mechanical ventilation resulted in more optimal pCO2 levels after transport. METHODS: We reviewed the hospital charts and transport records of all infants and children who had sustained a head injury and were transported by a specialized pediatric transport paramedic team to a single tertiary care facility during a 12-month period. All children were intubated and ventilated either mechanically or manually. Outcome measures were final pCO2 before transport and first pCO2 on arrival in the PICU. RESULTS: Twenty-nine children (age 0.6 to 16 years, mean 7.3, median 6) met the criteria. Fourteen patients were hand-bagged (HB), and 15 were mechanically ventilated (MV). Eleven patients (5 HB and 6 MV) started in the target pCO2 range of 35 to 40 mmHg. After transport, nine patients (all MV) had pCO2 within the target range (P < 0.01). Duration of transport (mean 63 minutes, range 15-200 minutes) did not contribute to the final pCO2 level. CONCLUSION: MV improves management of pCO2 during interfacility transport. HB significantly increases the incidence of suboptimal pCO2 and hence the risk of suboptimal cerebral blood flow. MV appears mandatory, and monitoring CO2 in transit (end-tidal or preferably point-of-care testing) should further reduce the likelihood of secondary complications from cerebral ischemia.

Adolescent↗