Anaesthesia and intensive care
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Anaesth Intensive Care · May 2011
Randomized Controlled TrialThe effect of the sitting upright or 'beachchair' position on cerebral blood flow during anaesthesia for shoulder surgery.
The sitting upright or 'beachchair' position is commonly used for shoulder arthroscopic surgery. There is a theoretical concern that anaesthetised patients placed in this posture are at risk of reduced cerebral blood flow (CBF), especially if there is associated hypotension. This study investigated the effect of anaesthetic-induced hypotension on estimated cerebral blood flow in patients placed in the beachchair position for shoulder surgery. ⋯ However, CBF remained constant in both anaesthetised (P = 0.83) and sedated patients (P = 0.68) despite beachchair positioning, and the fall in mean arterial pressure in the anaesthetised patients. There was no significant difference in CBF between groups (P = 0.91). These findings indicate that in patients in the beachchair position receiving sevoflurane anaesthesia, CBF is maintained when mean arterial pressure is above 70 mmHg, consistent with intact autoregulation.
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There is currently a shortage of organ donors to meet the demands of transplantation waiting lists. In recent years there has been renewed interest in donation after cardiac death in order to increase the pool of potential donors. The Organ and Tissue Authority has recently developed a national policy for donation after cardiac death. We describe here a checklist that is used by our hospital-based staff for organ donation which outlines important steps in the donation after cardiac death process.
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Anaesth Intensive Care · May 2011
Anaesthesia trainees' exposure to regional anaesthesia in an Australian tertiary adult teaching hospital.
The purpose of this study was to quantify the exposure of anaesthetic trainees to regional anaesthesia in an Australian tertiary adult teaching hospital. We reviewed data collected on all regional blocks performed by the anaesthetic department over a two-year period. The data was then broken down to give an estimate of the number of each block performed by each training year group. ⋯ The number of total blocks and the proportion of advanced blocks increased with increasing level of training while supervision declined. Trainees in the two regional fellowship positions (7% of the trainee pool) performed 42% of the 1374 blocks. Factors that may influence the exposure of trainees to regional anaesthesia and the assessment of competency are considered.
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Anaesth Intensive Care · May 2011
Intrabronchial airway pressures in intubated patients during bronchoscopy under volume controlled and pressure controlled ventilation.
Bronchoscope insertion through an endotracheal tube increases airflow resistance. Constant tidal volume (T(v)) ventilation can be maintained by augmenting the inspiratory pressure, but increased outflow resistance cannot be compensated for. Air trapping distal to the tube may lead to higher airway pressures in volume controlled (VC) mode and reduced T(v) in pressure controlled (PC) mode. ⋯ In PC mode, peak airway pressure was unchanged and end-expiratory airway pressure increased from 9.5 cmH2O (7 to 10) to 10.5 cmH2O (9 to 18) (P = 0.017). Median T(v) was reduced from 673 ml (585 to 800) to 450 ml (408 to 560) (P = 0.012); median P(a)CO2 increased from 5.7 kPa to 6.5 kPa (P = 0.012). Using distal measurement, positive end-expiratory airway pressure increased markedly in VC mode but only marginally in PC mode after bronchoscope insertion.
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Anaesth Intensive Care · May 2011
Rohrer's constant, K2, as a factor of determining inspiratory resistance of common adult endotracheal tubes.
The aim of the study was to calculate the in vitro inspiratory resistance (R(ETT)) of adult endotracheal tubes (ETT), via the end-inspiratory occlusion method, and to apply this method in vivo in order to estimate R(ETT) value in real time. By plotting R(ETT) over inspiratory flow (V) and calculating Rohrer's coefficients of linear and nonlinear resistance, K1 and K2 respectively, we determined the resistive behaviour of each ETT. Peak and plateau pressures were recorded at both proximal and distal sites of the ETT after applying a three-second occlusion under constant flow. ⋯ The intraluminal catheter increased R(ETT) No.7.0 by an average of 49%. Finally, ten patients with partially obstructed ETTs were tested and K2 in vivo constants found to be higher than their corresponding in vitro values (P value 0.00012). Therefore, knowing the performing size of an ETT may help the clinicians identify ETT obstruction and deal with weaning problems.