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Biomedical subjects

Daniel M Sado

Publications and source records attributed to Daniel M Sado.

8 recordsLinked to original sources
PubMed2005

Local anaesthesia for venous cannulation and arterial blood gas sampling: are doctors using it?

The pain of venous cannulation and arterial puncture can be greatly lessened by local anaesthesia. We sought information about the use of local anaesthesia for these procedures by doctors working in medicine, surgery and anaesthetics. A questionnaire was hand-delivered to 178 doctors in eight hospitals, all of whom responded. For insertion of large-bore cannulae, local anaesthesia was used by all the anaesthetists but less than half the medical and surgical doctors. For arterial blood sampling it was used by 60% of anaesthetists and 2% of ward doctors. Previous recommendations to use local anaesthesia seem to have been ignored, and in many instances these procedures are more painful than necessary.

Anesthesia, Local↗
PubMed2004

Comparison of the effects of removal of chest hair with not doing so before external defibrillation on transthoracic impedance.

Chest hair contributes significantly to transthoracic impedance (TTI) during defibrillation. The magnitude of this effect has not been established using external paddles. We compared TTI in 40 men before elective cardiac surgery, and before and after shaving their chests. Chest hair causes a significant increase in TTI during external defibrillation, the magnitude of the effect being related to both the quantity of hair and force applied to the defibrillation paddles. When the chests of nonhirsute patients were shaved, a decrease in TTI occurred, which was probably related to the creation of low-impedance pathways through skin abrasions.

Adult↗
PubMed2004

Differential contribution of skin impedance and thoracic volume to transthoracic impedance during external defibrillation.

BACKGROUND: Two mechanisms by which firm external paddle force decreases transthoracic impedance (TTI) have been proposed. Decreased impedance at the paddle-skin interface has been assumed to be the primary mechanism, but expulsion of air from the lungs, reducing lung volume is also likely to contribute. The relative contribution of each mechanism is unknown. METHODS AND RESULTS: Thirty five intubated patients undergoing general anaesthesia for cardiac surgery were studied. TTI across external defibrillation paddles was measured as paddle force was increased to 12kgf. Measurements were performed twice; once allowing the volume of the lungs to change and once with lung volume held at functional residual capacity. TTI with constant lung volume was significantly higher at (P< 0.001), confirming that a reduction in lung volume contributes to the decrease in TTI. At an optimal paddle force of 8kg, the reduction in lung volume contributed to 16.2% of the overall decrease in TTI. CONCLUSION: The decrease in TTI seen with increasing external paddle force is due primarily to improved electrical contact at the paddle-skin interface, with a decrease in thoracic volume accounting for no more than 16% of the overall decrease at forces used clinically.

Cardiac Surgical Procedures↗
PubMed2004

The incidence and severity of cutaneous burns following external DC cardioversion.

INTRODUCTION: Cutaneous burns are a common cause of morbidity following direct current (DC) cardioversion, but the incidence and severity have never been quantified. MATERIALS AND METHODS: Two hours after elective DC cardioversion in 83 sequential patients, we measured skin temperature, erythema index, and minimum sensory and pain detection thresholds at paddle sites and control sites on the contralateral side. Visual analogue pain score (VAS) was recorded at 2 and 24h post-cardioversion. RESULTS: Values for areas over paddle sites were higher (P < 0.05) than control site for all variables measured at 2h. Eighty-four percent patients experienced some pain and 23% patients experienced moderate to severe pain as assessed by VAS. Burns were greater at the edge than the centre of sternal sites and greater at sternal than apical sites. There were positive correlations between transthoracic impedance (TTI) and total energy delivered (r(2) = 0.048; P = 0.04); total energy and pain at 2 h (r(2) = 0.38; P < 0.0001) and 24 h (r(2) = 0.23; P < 0.0001); and number of shocks and pain at 2 h (r(2) = 0.36; P < 0.0001) and 24 h (r(2) = 0.19; P < 0.0001). CONCLUSION: Elective DC cardioversion causes burns as measured by skin temperature, erythema index and sensory threshold to sharp touch. Pain experienced is related to the total energy and number of shocks delivered. To reduce burns, operators should apply optimal paddle force equally to both paddles, with the paddles applied so as to provide even contact along their edges. Burns may also be minimised by starting with lower energy shocks.

Adult↗
PubMed2004

Prehospital end-tidal carbon dioxide concentration and outcome in major trauma.

BACKGROUND: End-tidal carbon dioxide (Petco2) concentration is a marker of the pathophysiologic state because it is a reflection of cardiac output. Petco2 correlates with outcome after prehospital primary cardiac arrest, but association with outcome from prehospital trauma has not been established. METHODS: Between 1998 and 2001, Petco2 was recorded in 191 blunt trauma patients requiring prehospital intubation. Rapid sequence intubation was performed using suxamethonium (1 mg/kg) and etomidate (0.2-0.3 mg/kg). Initial Petco2 after endotracheal intubation (t0) and Petco2 at 20 minutes after endotracheal intubation (t20) were recorded, together with survival to discharge. RESULTS: Median Petco2 at t20 was 4.10 kPa in survivors and 3.50 kPa in nonsurvivors (95% confidence interval of difference between medians, 0.40 to 0.90 kPa; p < 0.0001). Petco2 at t20 was a better predictor of outcome than at t0. CONCLUSION: Only 5% patients with Petco2 < 3.25 kPa survived to discharge. Petco2 at t20 is of value in predicting outcome from major trauma.

Adolescent↗
PubMed2003

Is the orientation of the apical defibrillation paddle of importance during manual external defibrillation?

OBJECTIVE: Transthoracic impedance (TTI) is a factor determining the magnitude of the transmyocardial current during external defibrillation. Minimising TTI increases the chances of successful defibrillation. Most external defibrillation paddles are rectangular in shape and can, therefore, be placed in a transverse or longitudinal orientation. The apical paddle is often placed in a transverse orientation. This may theoretically result in a higher TTI than a longitudinal orientation because of poorer contact at the lateral paddle edges. We compared TTI with the apical paddle in both a transverse and longitudinal orientation. MATERIALS AND METHODS: Twenty sequential anaesthetised patients were studied. A pair of defibrillator paddles were instrumented to measure paddle force. TTI was recorded pre-operatively at end-expiration with the apical paddle in both longitudinal and transverse orientations. The sternal paddle was placed in a longitudinal orientation for all measurements. RESULTS: TTI decreased in both transverse and longitudinal orientations as paddle force increased. Transverse paddle orientation resulted in a significantly (P<0.01) higher TTI than longitudinal orientation at all paddle forces below 12 kg force. CONCLUSION: The longitudinal orientation of a rectangular defibrillation paddle provides a lower TTI than orientation horizontally.

Electric Countershock↗