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Charles D Deakin

Publications and source records attributed to Charles D Deakin.

At least 19 recordsLinked to original sources
PubMed2007

A prospective manikin-based observational study of telephone-directed cardiopulmonary resuscitation.

INTRODUCTION: Bystander cardiopulmonary resuscitation (CPR) significantly improves the outcome from sudden cardiac arrest (SCA) and is therefore encouraged by offering telephone instructions to the bystander. The effectiveness of this technique was examined in a manikin-based study. METHODS: Subjects performed CPR on an instrumented adult manikin by following Advanced Medical Priority Dispatch System v11.1 (AMPDS) instructions given by telephone from a different room. RESULTS: Fifty-one volunteers (26 males, median age 56, range 27-76 years) with no previous experience of CPR were recruited. No volunteers followed the entire instructions correctly. Forty percent were unable to open the airway, only 18% achieved a median inspiration time of 2 s or greater and only 30% delivered tidal volumes within the range 700-1000 ml. Chest compressions were performed at a median rate of 52 min-1 with only 4% of subjects achieving a rate of 100 min-1. Depth of compression was also inadequate in 88% of subjects and hand positioning was incorrect in a third of subjects. The median duty cycle was 46% and there were significant delays between the commencement of the AMPDS protocol and the delivery of the first breath (123 s) and first chest compression (163 s). DISCUSSION: Few bystanders perform CPR satisfactorily and further work is necessary to improve the effectiveness of telephone CPR instructions.

Adult↗
PubMed2006

A randomized controlled trial of efficacy and ST change following use of the Welch-Allyn MRL PIC biphasic waveform versus damped sine monophasic waveform for external DC cardioversion.

OBJECTIVE: Biphasic waveforms have similar or greater efficacy at cardioverting atrial and ventricular arrhythmias at lower energy levels than monophasic waveforms, and cause less ST depression following defibrillation of ventricular fibrillation. No studies have investigated this effect on ST change with atrial arrhythmias. We studied the efficacy of the Welch Allyn-MRL PIC biphasic defibrillator. METHODS: One hundred and thirty-nine patients undergoing elective DC cardioversion for atrial arrhythmias were randomised to cardioversion by monophasic (Hewlett Packard Codemaster XL; 100, 200, 300, 360 and 360J) or biphasic (Welch Allyn-MRL PIC; 70, 100, 150, 200 and 300J) defibrillator. We analysed success of cardioversion after 0 and 30min, cumulative energy, number of shocks and energy at successful cardioversion. The ST change in the recorded electrocardiogram was measured at 15s after all shocks using electronic callipers. RESULTS: Immediately after cardioversion 59/68 (86.8%) of the monophasic group versus 56/60 (93.3%) of the biphasic group were in sinus rhythm. Of the monophasic group, 55/67 (82.1%) remained in sinus rhythm at 30min versus 53/58 (91.4%) of the biphasic group. These differences were not significant at 0min (P=0.35) or 30min (P=0.21). The biphasic group required significantly fewer shocks (P=0.006), less cumulative energy (P<0.0001) and required lower total energy for successful cardioversion (P<0.0001). Of the 102 patients with electrocardiogram recordings suitable for analysis, ST segment change was greater in the monophasic group (P=0.037). CONCLUSIONS: The Welch Allyn-MRL biphasic waveform for DC cardioversion results in fewer shocks, with less cumulative energy delivered and less post shock ST change than with a Hewlett Packard Codemaster XL damped sine wave monophasic waveform.

Adult↗
PubMed2006

A randomised controlled trial of the effect of biphasic or monophasic waveform on the incidence and severity of cutaneous burns following external direct current cardioversion.

OBJECTIVE: Cutaneous burns are a common cause of morbidity following direct current (DC) cardioversion. We designed a prospective randomised double-blinded controlled study to determine the effect of biphasic or monophasic waveform on the pain and inflammation occurring after elective cardioversion. MATERIALS AND METHODS: One hundred and thirty nine patients undergoing elective DC cardioversion were randomised to receive monophasic (HP Codemaster XL; 100, 200, 300, 360, and 360 J) or biphasic (Welch Allyn-MRL PIC defibrillator; 70, 100, 150, 200, and 300 J) waveforms. Two hours after DC cardioversion, skin temperature, erythema index and sensory threshold to light and sharp touch was measured at the centre and edge of paddle sites. Visual analogue pain score (VAS) was recorded at 2 and 24 h. RESULTS: There was significantly less pain following biphasic cardioversion as assessed by VAS at both 2 h (p < 0.001; 95% confidence intervals of difference of medians (CI) 0.2-0.8 cm) and 24 h (p = 0.004; 95% CI 0.0-0.4 cm). There was significantly less erythema in patients receiving biphasic cardioversion at the edge of the sternal site (p = 0.046; 95% CI 0.41-4.5). There was no difference in any other variable at any site between biphasic and monophasic cardioversion. CONCLUSION: The use of a biphasic waveform for DC cardioversion reduces the inflammation and pain of burns as measured by erythema index and visual analogue scale.

Adult↗
PubMed2005

Post-shock myocardial stunning: a prospective randomised double-blind comparison of monophasic and biphasic waveforms.

INTRODUCTION: Compared with monophasic defibrillation, biphasic defibrillation is associated with less myocardial stunning and earlier activation of sodium channels. We therefore hypothesised that earlier sodium channel activation would result in earlier restoration of the first sinus beat following elective DC cardioversion. METHODS: Adults undergoing elective DC cardioversion were randomised to receive either monophasic or biphasic escalating transthoracic shocks. The ECG was recorded electronically during defibrillation and the time from delivery of the shock to restoration of the first sinus beat, measured from the beginning of the 'P' wave, was calculated. RESULTS: Seventy four patients were studied. Data were unavailable from 18 patients. There was no demographic difference between groups. Median time to the first sinus beat following monophasic defibrillation (n=25) was 3.66 s (95% CI 2.55-4.61 s) and following biphasic defibrillation (n=33) was 2.21s (95% CI 1.76-2.56 s; P<or=0.0001). Linear regression confirmed that the waveform was an independent predictor of time to restoration of sinus rhythm; P<0.0001. The final defibrillation energy level used to achieve cardioversion was not an independent predictor of time to restoration of sinus rhythm; P=0.49. CONCLUSION: Biphasic defibrillation for elective DC cardioversion achieved more rapid restoration of the first sinus beat compared with a monophasic waveform. Waveform, but not energy level that achieved defibrillation, was an independent predictor of time to restoration of the first sinus beat. The mechanism for this may be related to the earlier reactivation of sodium channels associated with the biphasic waveform.

Aged↗
PubMed2005

Pre-hospital fluid therapy in the critically injured patient--a clinical update.

Venous access and fluid therapy should still be considered to be essential elements of pre-hospital advanced life support (ALS) in the critically injured patient. Initiation of fluid therapy should be based on a clinical assessment, most importantly the presence, or otherwise, of a radial pulse. The goal in penetrating injury is to avoid hypovolaemic cardiac arrest during transport, but at the same time not to delay transport, or increase systolic blood pressure. The goal in blunt injury is to secure safe perfusion of the injured brain through an adequate cerebral perfusion pressure, which generally requires a systolic blood pressure well above 100 mmHg. Patients without severe brain injury tolerate lower blood pressures (hypotensive resuscitation). Importantly, using systolic blood pressure targets to titrate therapy is not as easy as it seems. Automated (oscillometric) blood pressure measurement devices frequently give erroneously high values. The concept of hypotensive resuscitation has not been validated in the few studies done in humans. Hence, the suggested targeted systolic blood pressures should only provide a mental framework for the decision-making. The ideal pre-hospital fluid regimen may be a combination of an initial hypertonic solution given as a 10-20 minutes infusion, followed by crystalloids and, in some cases, artificial colloids. This review is intended to help the clinician to balance the pros and cons of fluid therapy in the individual patient.

Blood Pressure↗
PubMed2005

The effect of topical non-steroidal anti-inflammatory cream on 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. We designed a study to determine whether the application of non-steroidal anti-inflammatory cream prior to cardioversion reduces their incidence and severity. MATERIALS AND METHODS: Two hours before elective DC cardioversion, we randomised 55 patients to receive ibuprofen 5% cream or placebo cream over sternal and apical pad sites, with patients acting as their own controls. Two hours after cardioversion an independent blinded observer measured skin temperature, erythema index, and minimum sensory and pain detection thresholds at sternal and apical pad sites. Visual analogue pain score (VAS) for each site was recorded at 2 h and 24 h post-cardioversion. RESULTS: There was a statistically significant difference between pain measured by VAS, skin temperature and pain detection threshold measured at pad sites with pre-applied ibuprofen 5% cream and those with pre-applied aqueous cream, after elective DC cardioversion. CONCLUSION: Prophylactic application of topical ibuprofen 5% cream 2h prior to elective DC cardioversion reduces pain and inflammation. Consideration should be given to use of prophylactic application of topical ibuprofen as routine treatment for elective DC cardioversion.

Administration, Topical↗
PubMed2005

The effect of prophylactic topical steroid cream on 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. We designed a prospective double-blinded controlled study to determine whether the application of steroid cream prior to cardioversion reduces their incidence and severity. MATERIALS AND METHODS: Two hours before elective DC cardioversion, we applied betamethasone 0.1% cream or placebo cream over sternal and apical pad sites in 56 patients, with patients acting as their own controls. Two hours after cardioversion, a separate blinded observer measured the visual analogue pain score (VAS), sensory and pain detection thresholds, skin temperature and erythema index at sternal and apical pad sites. RESULTS: The study had an 80% power to detect a 50% difference in VAS at 2 h, accepting an alpha error of 0.05. There was no difference between pain at 2 or 24 h, skin temperature, erythema index, sensory and pain detection thresholds at pad sites treated with steroid cream or control. CONCLUSION: Topical betamethasone 0.1% cream applied 2 h before elective DC cardioversion is no more effective than placebo at reducing the pain and inflammation from cardioversion burns.

Administration, Topical↗
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

Is optimal paddle force applied during paediatric external defibrillation?

INTRODUCTION: Optimal paddle force minimises transthoracic impedance; a factor associated with increased defibrillation success. Optimal force for the defibrillation of children < or =10 kg using paediatric paddles has previously been shown to be 2.9 kgf, and for children >10 kg using adult paddles is 5.1 kgf. We compared defibrillation paddle force applied during simulated paediatric defibrillation with these optimal values. METHODS: 72 medical and nursing staff who would be expected to perform paediatric defibrillation were recruited from a University teaching hospital. Participants, blinded to the nature of the study, were asked to simulate defibrillation of an infant manikin (9 months of age) and a child manikin (6 years of age) using paediatric or adult paddles, respectively, according to guidelines. Paddle force (kgf) was measured at the time of simulated shock and compared with known optimal values. RESULTS: Median paddle force applied to the infant manikin was 2.8 kgf (max 9.6, min 0.6), with only 47% operators attaining optimal force. Median paddle force applied to the child manikin was 3.8 kgf (max 10.2, min 1.0), with only 24% of operators attaining optimal force. CONCLUSION: Defibrillation paddle force applied during paediatric defibrillation often falls below optimal values.

Body Weight↗
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↗