Ice Pads Research Articles

Relationship of Abdominal Circumference and Trunk Length With Spinal Anesthesia Block Height in Geriatric Patients Undergoing Transurethral Resection of Prostate.

Spinal anesthesia is commonly used for various surgical procedures. Prediction of spinal anesthesia block height is always a challenging task for anesthetists. Higher than desired levels of spinal anesthesia blocks are associated with serious side effects, while inadequate block height does not provide satisfactory surgical anesthesia. In this study, we observed the relationship between the ratio of trunk length (TL) and square of the abdominal circumference (AC2) and spinal anesthesia sensory block height in geriatric patients undergoing transurethral resection of the prostate (TURP). This is a cross-sectional study conducted at the Aga Khan University Hospital Karachi, Pakistan, on geriatric patients undergoing TURP under spinal anesthesia. Forty-three elderly patients (American Society of Anaesthesiology levelI-III)between 60 and 80 yearswere recruited for the study. In hospital wards, trunk length (TL) and abdominal circumference were recorded before the procedure. In the operating rooms, spinal anesthesia was performed at L3-L4 intervertebral space with 0.5% hyperbaric bupivacaine 10mg (2mls). Block height was measured by the placement of ice pads at different dermatomes. Spearman rank correlation coefficient was used to analyze the physical parameters (TL/AC2) and spinal anesthesia block height. Results: The ratio of trunk length and square of the abdominal circumference (TL/AC2) correlates with spinal anesthesia block height in geriatric patients, where the spearman rank correlation coefficient was r =-0.284 with p = 0.015. The ratio of the long axis (TL) and transection area of the abdomen (AC2), which coincides with (TL/AC2), correlated with spinal anesthesia sensory block height. Hence, elderly patients with a low TL/AC2ratio will have higher block height after spinal anesthesia.

Reanimate the Dead to Life by Practicing Cryo Techniques

Therapeutic Hypothermia has been evolving as a science in itself since a very long time. There have been many accidents chronicled wherein people were buried alive in snow or under ice in frigid waters, left scientifically dead without any signs of heartbeat and breathing, only to be revived many hours later. The most notable case being that of Anna Bagenholm from Sweden. Doctors in Siberia have been placing babies in snowbanks since the 1960’s before surgery to increase their chances of survival. Stowaways have been known to survive in the wheel well of an aircraft jetliner at 38,000 feet altitude with negligible oxygen & -50 degree temperatures. Inspiration is also drawn from hibernation ability of the hibernating animals like the artic ground squirrel, wood frog, nematodes, polar bears etc. in harsh winter conditions. But it has been felt that the real benefits of medical hypothermia have not been exploited so far for the progress of mankind. By means of this research, we have now discovered how cooling can assist in bringing back the dead to life. Pigs were bled to death with a major trauma to their vital common jugular vein and/or carotid artery to mimic an accident/trauma injury. The pig had by now lost its heartbeat, pulse, blood pressure, respiration, etc. and all other vital signs of life, leaving it clinically dead. Its chest cavity was opened via a thoracotomy. A cannula or long specialized Cather was inserted into the aorta. Dead bodies of these pigs were immediately cooled by sucking out their entire blood through the aorta & replacing it with an ice cold saline solution (at 5 degrees Celsius) suspended with PFC’s - Perfluorocarbon aggressively pumped into the aorta. PFC’s are efficient artificial oxygen carriers. All this drained blood of the pig was carefully collected in a vat for re-transfusion in future. This cold oxygenated solution was continuously circulated through the blood vessels of the dead pig bringing its core body temperature to about 10 degrees Celsius rapidly within 10 minutes. An ECMO machine was connected with a chiller and heater alternatively, used continuously for all circulatory purposes of both the warm blood & ice-cold solution throughout the pig’s body. External cooling packs & ice pads were also applied on the entire body of the pig to cool down its dead body as soon as possible. A surgery was performed on the dead body to restore the tear (sew up the vein which had been severed). The pig was slowly thawed in a warm water bath at about 0.5 degree Celsius per hour to the normal body temperature of 38 degrees of the pig. The ice-cold saline was then replaced with the warm original blood of the pig when the temperature reached 30 degrees. After about reaching to 32 degrees some of the pig’s heart started beating automatically while the others had to be given a jumpstart using external electric shocks called defibrillation or Electrical Cardioversion. The pigs were immediately connected to a ventilator device for assisted respiration. After about a day or so, these pigs returned to normalcy with regards to heart & breathing rhythms. By following the above procedure, dead humans may also be brought back to life immediately after demise. This procedure will be more effective in dead youths who unfortunately were killed. Pigs were used for this experiment as they share a number of surprising comparable traits with humans, which is a well-known fact.

Effects of plantar hypothermia on quasi-static balance: Two different hypothermic procedures

Inducing hypothermia to examine its effects on balance is performed with various approaches. However, data interpretations of underlying postural mechanisms often do not consider the applied hypothermic protocol. In this context, the effects of diminished plantar mechanoreceptor activity on quasi-static balance performance were investigated, examining the applicability of a continuously cooling thermal platform in comparison with conventional ice pads. Increased instability for the thermal platform compared to cooling with ice pads was hypothesized, since we expected increased temperatures for the ice pad group directly after balance tests. Similar scores on a Visual Analogue Scale (VAS) were predicted regarding subjective pain. Results showed that both cooling procedures successfully induced plantar hypothermia. However, the thermal platform was more effective with respect to reaching and maintaining the desired temperature throughout the trials, especially when comparing temperatures before and after balance tests. Therefore, balance tests indeed demonstrated increased COP parameters exclusively after permanent cooling via the thermal platform as early as after the first 10 min of cooling. Reduced plantar input may result in this postural instability, but without the need of other sensory systems to compensate. The VAS generally demonstrated higher pain scores for the ice pads, rejecting our hypothesis. This is an important finding, since pain is known to influence balance. Therefore, permanent and controllable cooling via the thermal platform should be taken into consideration when conducting related research.

Abstract 323: Intra-arrest Induction of Preferential Brain Cooling With Mild Systemic Hypothermia Does Not Correlate With Favorable Outcome in a Rabbit Model of Ventricular Fibrillation

Introduction: Recent reports suggested that poor clinical outcomes correlate with rapid cooling in cardiac arrest patients. The possible causes are unclear. We have now compared survival between intra-arrest induction of preferential brain cooling with mild systemic hypothermia and conventional surface cooling animals, and focused on the relationship between hemodynamics and brain temperature (Tb). Methods: Untreated VF of 4 min and CPR of 4min were given to 24 rabbits prior to defibrillation. Animals were randomly assigned to (1) preferential brain cooling by a neck cooling collar initiated at beginning of CPR, (2) body surface cooling by ice pads and fan initiated at 30 min after ROSC, (3) spontaneous normothermia control. Core body temperature (Tc) and Tb were monitored by thermoprobes in rectum and brain parenchyma respectively. Mean aortic pressure (MAP), heart rate (HR), LV dp/dt, LV -dp/dt, and PetCO2 were continuously monitored. During 4 hrs of cooling, Tc was maintained between 33.5°C and 34.5°C by turning on/off the cooling regardless Tb. Cooling would also be paused if MAP is below 60 mmHg. Methods for control animals were identical except for cooling. Results: Six of 8 animals in each group achieved ROSC and survived to 18±17, 17±18, and 21±23 hrs after ROSC respectively, P=0.921. First time pause of cooling due to low MAP only occurred in all 6 brain cooling animals. At first pause of cooling, Tb and Tc were 34.1±0.8°C and 33.5±0.2°C in body cooling animals, but were 29.2±1.3°C and 35.5±0.9°C in brain cooling animals respectively. MAP and HR in brain cooling animals were significantly lower than those in body cooling and control animals at 30min, and 60 min after ROSC (Table). Linear regression analysis showed that Tb but not Tc was the independent influential factor for MAP after ROSC. Conclusions: Early induction of preferential brain cooling does not necessarily improve outcome after ROSC. Hypotension correlates with low Tb and warrants close monitoring and management.

Abstract 180: Mild Systemic Hypothermia Induced by Preferential Brain Cooling Suppresses Cardiovascular Functions More Significantly Than That Induced by Systemic Cooling in a Rabbit Model

Introduction: The optimal target temperature for preferential brain cooling is unclear. Hypothesis: Preferential brain cooling suppresses cardiovascular functions more significantly than systemic cooling with the same core body temperature (Tc) target of therapeutic mild hypothermia (TMH). Methods: After anesthesia and instrumentation, five rabbits first received preferential brain cooling by using a semiconductor neck cooling collar starting from 37°C of Tc to the target of 34°C. Then after rewarming to 37°C of Tc by warming blanket, the animals received systemic cooling with the same Tc target by ice pads and fan. Another five rabbits first received systemic cooling, and then received neck cooling with the same procedures. Mean arterial pressure (MAP), heart rate (HR), left ventricular systolic pressure (LVSP), LV dp/dt, LV -dp/dt, respiratory rate (RR), PetCO2, brain temperature (Tb) and Tc were continuously monitored and recorded at 0.2°C interval of Tc during hypothermia in all animals. For monitoring Tb and Tc, thermoprobes were placed into brain parenchyma and rectum respectively. Paired t-test were used to compare measurements at 37°C and 34°C of Tc. Results: During systemic cooling, Tb decreased in parallel with Tc. Only HR decreased significantly from 249±13 bpm at 37°C to 216±14 bpm at 34°C, P<0.001. No significant changes were detected in MAP, dp/dt, -dp/dt, LVSP, RR and PetCO2. In contrast, during neck cooling, Tb decreased 3.1±1.2°C more than Tc at 34°C of Tc. At meantime, MAP decreased significantly from 98±8 mmHg at 37°C to 84±7 mmHg at 34°C, P<0.001. HR, dp/dt, LVSP also decreased significantly, all p<0.01. RR, PetCO2 and -dp/dt did not change significantly. Pearson correlation analysis showed MAP was more closely related to Tb than to Tc, the coefficients were 0.539 (P<0.001) and 0.158 (P=0.002) respectively. Multiple linear regression analysis also showed a higher standardized coefficient of Tb than that of Tc for MAP (0.667 vs. -0.224), indicating that Tb has a greater effect on MAP than Tc. Conclusions: Preferential brain cooling suppresses cardiovascular functions more significantly than systemic cooling when achieving the same core body temperature target of TMH. Brain temperature has a greater impact on MAP than core body temperature during TMH.

Sliding resistance of grounded ice on clay in a laboratory: Potential implications for offshore design

Abstract Grounded ice pads as a base for exploration drilling platforms are built by artificially thickening the ice cover, made from either level ice or ice rubble, at the desired drilling location. An experimental set-up was assembled with the purpose of addressing outstanding issues regarding the sliding resistance of these structures. These simulations were done on a clay seabed. The ice was contained in a bottomless rectangular box, called the 'wagon'. The bottom of the ice was in contact with the clay, with a 4 m 2 footprint, and normal stress levels up to 23 kPa. The wagon was pulled by an actuator over distances of up to 100 mm per test while monitoring the horizontal forces required to do so. A total of 29 successful tests were conducted with level ice and another 32 with ice rubble. In the case of level ice, an increase in normal stress only resulted in a small increase in shear resistance, when enough time was allowed for the clay to consolidate. With ice rubble, an increase in normal stress systematically led to a significant increase in shear resistance, presumably because of shorter drainage paths for pore water evacuation, suggesting this material should be more suitable than level ice for this purpose. Vertical motion upon increasing and decreasing the normal stress provided evidence for clay consolidation and swelling, respectively. A peak response in shear resistance is attributed to dilatation. The clay's undrained shear strength, measured with a vane, was consistently higher than the sliding resistance of the ice in all tests. The vane data could therefore not be relied upon to provide a measure of sliding resistance. Also, this parameter progressively increased to levels well exceeding the maximum normal stress applied to the clay. An alternative approach, based on the soil's effective internal friction response, is assessed and proposed for estimating sliding resistance of real ice pads and other structures resting on a clay-rich seabed.

Laboratory study on the sliding resistance of level ice and rubble on sand

Abstract An experimental set-up was constructed to study the friction behaviour of level ice and ice rubble on different seabeds at large scale and realistic stress levels. This paper presents the results of loading on a sand seabed. The tests were performed with a 4 m 2 footprint with vertical stress levels up to 17 kPa. The ice was moved horizontally a distance of about 120 mm with displacement rates from 0.003 to 0.342 mm/s. Four position transducers measured vertical displacements. A total of 47 tests were conducted with level ice and another 24 with ice rubble. Friction coefficients of 0.47 and 0.39 for peak and steady shear stresses, respectively, were obtained with level ice. Those produced with ice rubble were 0.65 and 0.62 for the peak and steady shear resistance, respectively, which represents an increase of about 50% in shear resistance compared with level ice. Shear failure is believed to have occurred at the ice–sediment interface, although the sand's internal friction may have been fully mobilized by the ice rubble. Sediment freeze-up caused a substantial increase in sliding resistance. During this process, the failure plane is believed to have migrated downward and laterally along the freezing front, into the sand bed, with a concurrent increase in shear resistance up to levels comparable to the sand's internal friction. Sand compaction may have contributed also in increasing sliding resistance. These results may be useful for the design of spray ice pads and to assess the stability of grounded ice features.

Relación entre temperatura corporal y pronóstico, y efecto neuroprotector de la hipotermia en pacientes con ictus agudo

We review the relationship between body temperature and severity of acute stroke, and evaluate published evidence about the possible neuroprotective effect of hypothermia in these patients.In acute stroke patients, hypothermia increases oxygen consumption and metabolic demands of cerebral cells, favors liberation of oxygen radicals, glutamate, and other neurotransmisors involved in brain injury, and enhances biochemical processes leading to apoptosis. Preliminary data suggest that induced hypothermia is feasible and relatively safe in acute stroke patients; this may lead to a better outcome in terms of reduced mortality and less disabling sequelae in survivors. To enhance its possible efficacy, hypothermia should be started in the first 6 to 12 hours after the event, should be prolonged for at least 24 to 48 hours, and should be done with cooling blankets or ice pads, as antipyretics are not effective to induce hypothermia in normothermic subjects.Hyperthermia is deleterious in acute stroke patients and must be treated. Hypothermia should not be considered a routine procedure in these patients until its safety and efficacy has been demonstrated in large trials. Patients with induced hypothermia should be closely monitorized to reduce the risk of adverse effects related to the procedure.

Acoustics and sound-system design for the National Ice Centre, Nottingham, UK

The National Ice Centre, Nottingham is a unique indoor arena within the UK, as it will house two full-size ice pads both capable of hosting national and international ice-skating competitions. One of the ice pads will be permanently available for both local community (public) and professional ice-skating activities. The other pad, located in the main arena, can be covered over and the arena used to seat audiences of up to 10<th>000 spectators for pop concerts, major artist performances, sports events (e.g., tennis or boxing), and large conferences/meetings/exhibitions/conventions. The main arena will also host national and international ice dance and skating competitions. With such a wide range of activities, considerable attention has been paid to both the acoustics of the place and the installed sound systems. The paper describes both the acoustic treatment of the arena and the design philosophy and testing of the complex sound systems. The sound-system design is unusual for such a venue in that two separate systems are installed to cater to both the performance sound and voice alarm (fire alarm) needs without compromising the strict requirements relating to public safety in a building of this nature and size.