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Medical problems from cold exposure.

Problems resulting from cold exposure can be successfully treated when a coordinated emergency medical transport system and appropriate equipment are available, as well as medical personnel knowledgeable in the management of frostbite and hypothermia. Clinical suspicion of these disorders is essential. Profoundly hypothermic individuals with no recordable vital signs have been resuscitated after controlled, rapid rewarming measures and the use of emergency life-support systems.

Central Venous Pressure↗

Increased urinary concentration of catecholamines in hypothermia deaths.

Observations are presented on 24 hypothermia deaths, either accidental or suicidal. Most cases occurred in dry, cold circumstances, the air temperature being below 0 degree C. More cases were seen in early winter, suggesting a lack of acclimatization to the cold. Purple skin and swelling of the ears and nose (mild frostbite) were the most frequent external signs of exposure. Frequent internal signs were stomach ulcerations or hemorrhagic gastritis and small degenerative foci in the myocardium. High blood alcohol (about 200 mg/dL) was the most common contributory factor, but psychotropic drugs were detected in a few cases. The total urinary catecholamine content was increased in the hypothermia deaths, with levels of 0.20 +/- 0.16 microgram/mL (mean +/- standard deviation) versus 0.07 +/- 0.07 microgram/mL in sudden natural deaths and 0.02 +/- 0.02 microgram/mL in rapid violent deaths. Adrenaline was more abundant than noradrenaline. It is suggested that urine catecholamine measurements can give useful information for the diagnosis of acute hypothermia.

Adult↗

[Effectiveness of oxytetracycline and chingamin on cold injury in rats].

The preventive and therapeutical effects of oxytetracycline hydrochloride, 10 mg/kg b.w., and chingamine, 50 mg/kg b.w., were studied in frostbites caused by ethyl chloride. The experiments were conducted on adult albino Wistar rats. The two drugs given orally twice a day for 15 days or more prevented the development of frost bite; clinical, biochemical, and histological parameters becoming normal. Chingamine was found to be more effective, which makes it promising for further experimental and clinical studies.

Animals↗

American College of Sports Medicine position stand. Heat and cold illnesses during distance running.

Many recreational and elite runners participate in distance races each year. When these events are conducted in hot or cold conditions, the risk of environmental illness increases. However, exertional hyperthermia, hypothermia, dehydration, and other related problems may be minimized with pre-event education and preparation. This position stand provides recommendations for the medical director and other race officials in the following areas: scheduling; organizing personnel, facilities, supplies, equipment, and communication; providing competitor education; measuring environmental stress; providing fluids; and avoiding potential legal liabilities. This document also describes the predisposing conditions, recognition, and treatment of the four most common environmental illnesses: heat exhaustion, heatstroke, hypothermia, and frostbite. The objectives of this position stand are: 1) To educate distance running event officials and participants about the most common forms of environmental illness including predisposing conditions, warning signs, susceptibility, and incidence reduction. 2) To advise race officials of their legal responsibilities and potential liability with regard to event safety and injury prevention. 3) To recommend that race officials consult local weather archives and plan events at times likely to be of low environmental stress to minimize detrimental effects on participants. 4) To encourage race officials to warn participants about environmental stress on race day and its implications for heat and cold illness. 5) To inform race officials of preventive actions that may reduce debilitation and environmental illness. 6) To describe the personnel, equipment, and supplies necessary to reduce and treat cases of collapse and environmental illness.

Frostbite↗

[Travelers exposed to extreme temperatures].

Sudden introduction of the unadapted human into extreme environments can result in serious, sometimes fatal, reactions. Most complications are due either to failure of thermoregulatory system or consecutive to the physiological responses to those environmental conditions. In addition to a number of minor diseases, cold can cause two major accidents, i.e., hypothermia and frostbite which can be enhanced at altitude. Moreover, the main disease in altitude conditions is represented by the acute mountain sickness which can lead to acute pulmonary and cerebral edema. Heat can cause heatstroke, dehydration, syncope, and other minor disorders. Prevention of these manifestations during stays in inhospitable climatic conditions for which the body is not suited requires knowledge of the environment and its dangers. Implementation of suitable measures can greatly reduces the incidence of adverse effects.

Adaptation, Physiological↗

Optimal cryogen spray cooling parameters for pulsed laser treatment of port wine stains.

BACKGROUND AND OBJECTIVE: In dermatologic laser therapy, cryogen spray cooling (CSC) is a means to protect the epidermis while leaving dermal structures susceptible to thermal damage. The purpose of this study was to determine optimal spurt duration, tau(s), and optimal delay, tau(d), between the cryogen spurt and laser pulse when using CSC in treatment of port wine stain birthmarks. STUDY DESIGN/MATERIALS AND METHODS: A finite difference method is used to compute temperature distributions in human skin in response to CSC. Optimal tau(s) and tau(d) are determined by maximizing the temperature difference between a modeled basal layer and an imaginary target chromophore. RESULTS: The model predicts an optimal tau(s) of 170-300 msec and approximately 400 msec for shallow (150 microm) and deeper (400 microm) targets, respectively. Spraying for longer than the optimal tau(s) does not critically impair cooling selectivity. For a spurt duration of 100 msec, optimal delays are 5-10 msec and 25-70 msec for a shallow and deep basal layer, respectively. CONCLUSION: In the absence of knowledge about the lesion anatomy, using a tau(s) of 100-200 msec and no delay is a good compromise. A delay is justified only when basal layer and target chromophore are relatively deep and the optimal spurt duration cannot be applied, e.g., to avoid frostbite.

Cryotherapy↗

Effects of castration on antler growth in fallow deer (Dama dama L.).

Morphology and histological structure of antlers grown after castration (performed on March 25) were studied in six young fallow bucks. In the year after castration, antlerogenesis occurred during the species-specific time span, and the shape of the antlers, which remained permanently in velvet, was normal. During a cold period in December/January, the distal parts of the antlers suffered from frostbite and were subsequently detached. The process of sequestration was similar to that leading to normal antler casting. The sequestration sites were soon covered with skin, but (limited) regrowth of antler tissue from the stumps was not observed before late April/early May, i.e., the time of normal antler regeneration. Simultaneously, growth of knobby protuberances started on the surface of the antlers. Histological analysis of biopsies taken on December 20 in the year after castration revealed that the central parts of the antlers consisted of cancellous lamellar bone with mainly secondary osteons. Peripheral to this, the bone tissue (forming the protuberances) was of a more immature nature and exhibited larger intertrabecular spaces. The outermost layer consisted of woven bone formed by intramembranous ossification from the periosteum and was undergoing active growth and remodeling at the time of biopsy. Thus, bone formation at these sites occurred during a period when no antler growth is observed in normal fallow bucks. The velvet covering the bony protuberances was of normal appearance.

Animals↗

Cold-induced vasodilatation of finger and maximal oxygen consumption of young female athletes born in Hokkaido.

To determine whether there is a direct correlation between endurance capacity and cold tolerance, maximal oxygen consumption (VO2max), and cold-induced vasodilatation (CIVD), we measured these factors in 14 young female athletes born in Hokkaido, Japan's northernmost island. We determined the VO2max by a standard incremental test on a cycle ergometer and measured the oxygen consumption (VO2) by means of the Douglas-bag method. We determined the CIVD reaction by measuring the skin temperature of the left middle finger during immersion in cold water at 0 degree C for 20 min. The athletes showed significant positive correlations between VO2max, expressed as 1/min, and CIVD as well as other peripheral cold tolerance indexes (resistance index against frostbite and CIVD index). The body weight VO2max (VO2max/kg body weight) failed to correlate significantly with either the CIVD or with other cold tolerance indexes. These results suggest that CIVD in females may depend on factors other than those determined in this study, in addition to the functional spread of the vascular beds in peripheral tissues, including striated muscle; it is known that the size and the vascular bed in this tissue are affected by exercise training and that this results in the elevation of VO2max and VO2max/kg body weight.

Acclimatization↗

Upper extremity gangrene secondary to superior mesenteric artery infusion of vasopressin.

This patient demonstrates that peripheral vascular ischemia and gangrene may complicate the use of intraarterial vasopressin in the absence of catheter-related phenomena such as microemboli or catheter dislodgement. Discontinuation of vasopressin effectively reverses ischemic changes. Sympathetic blocking agents or direct-acting vasodilators may accelerate the reversal of the vasopressin induced ischemia. In the patient with a history of previous extremity cold injury, vasopressin may precipitate severe ischemia or gangrene by its direct effect at the arteriolar level in an extremity with already increased sympathetic vascular tone. Peripheral circulatory status must be assessed frequently during vasopressin infusion especially in patients with a history of frostbite.

Aged↗

Characterization of freeze-thaw induced ultrastructural damage to endothelial cells in vitro.

The pathophysiology of endothelial cells is important to a variety of vascular conditions including coagulation and hemostasis resulting from clinical frostbite. Use of an in vitro model system demonstrated that when bovine endothelial cells were frozen at 1 degrees C or 20 degrees C/min and thawed immediately (20 degrees C/min), a variety of ultrastructural alterations occurred. Membranous structures were most extensively damaged, with mitochondria the most sensitive organelle. Low amplitude mitochondrial swelling, first evident at 0 degrees C, progressed to high amplitude swelling by -10 degrees C (frozen). In addition, the rough endoplasmic reticulum was dilated and formed large vesicles with a homogeneous matrix. Nuclear changes first occurred at -15 degrees C. These included separation and distortion of the nuclear membrane, changes in chromatin distribution, and disruption of the nucleolus. Scanning electron microscopy revealed perforated plasma membranes in some cells at -10 degrees C (frozen) and in most cells by -20 degrees C. Cultures frozen at 20 degrees C/min revealed mostly the same ultrastructural damage noted at 1 degrees C/min except a higher percentage of cells exhibited alterations. Data from the recovery index and lactic dehydrogenase (LDH) release correlated well with observed ultrastructural changes. Early swelling of mitochondria and dilation of rough endoplasmic reticulum was not lethal in the absence of freezing. Increased swelling in cytoplasmic organelles coupled with nuclear alterations at -15 degrees C resulted in a decreased survival rate and release of significant quantities of LDH by -20 degrees C. No unique morphological changes were temperature specific, but the total number of cells that displayed alterations increased as temperature decreased.

Animals↗

The acrophysis: a unifying concept for understanding enchondral bone growth and its disorders. II. Abnormal growth.

In order to discuss and illustrate the effects common to normal and abnormal enchondral bone at the physes and at all other growth plates of the developing child, the term "acrophysis" was proposed. Acrophyses include the growth plates of secondary growth centers including carpals and tarsals and apophyses, and the growth plates at the nonphyseal ends of small tubular bones. Abnormalities at acrophyseal sites are analogous to those at the physeal growth plates and their metaphyses. For example, changes relating to the zone of provisional calcification (ZPC) are often important to the demonstration of such similarities. Lead lines were an early example of the concept of analogy from abnormality due to physeal and to acrophyseal disturbance. The ZPC is a key factor in understanding patterns of rickets and its healing. Examples (including hypothyroidism, scurvy and other osteoporosis, Ollier disease, achondroplasia, and osteopetrosis, as well as the family of frostbite, Kashin-Beck disease, and rat bite fever) illustrate the acrophysis principle and in turn their manifestations are explained by that principle.

Bone Development↗

General and local cold responses in humans after 2 weeks at high altitude.

To investigate the effects of a short-term high altitude residence (2 weeks between 4150 m and 6885 m in the Andes) on the general and local cold responses after descent, 11 subjects were submitted both to a whole body standard cold air test (SCAT, dry bulb temperature = 1 degree C, 2 h, nude, at rest) and to a local cold water test of the right upper limb (CWT, 5 degrees C, 5 min) both before and after the expedition. Compared to before the expedition, a lower systolic blood pressure was observed after the high altitude residence [130.00 (SEM 3.35) mm Hg vs 140.40 (SEM 4.74) mm Hg at the end of CWT, P < 0.05] whereas no significant change either in diastolic blood pressure or in heart rate was found. All skin temperatures of the right upper limb were lowered (P < 0.05). During SCAT, body temperatures were unchanged (rectal and mean skin temperature, Tsk) but metabolic heat production was slightly but significantly diminished [110 (SEM 4) W.m-2 vs 125 (SEM 3) W.m-2, P < 0.05] and heat debt increased [11.37 (SEM 1.11) kJ.kg-1 vs 9.30 (SEM 2.30) kJ.kg-1, P < 0.05]. Moreover, the time of onset of continuous shivering (d) was shortened [8.20 (SEM 1.90) min vs 17.30 (SEM 3.60) min, P < 0.05] and the level of Tsk observed at (d) was higher [25.70 (SEM 0.80) degrees C vs 23.57 (SEM 0.78) degrees C, P < 0.05] suggesting an increase in the sensitivity of the thermoregulatory system despite the slight decreased shivering activity observed. It was concluded that general and local cold tolerance were modified by a short-term residence at altitude and that the changes observed were not in accordance with general or (and) local cold adaptation. In contrast, high altitude sojourn could be a risk factor for frostbite of the extremities.

Altitude↗

Bilateral below-knee amputations: experience with 80 patients.

This review expands information concerning the bilateral below-knee (BK) amputee, describing the findings of a retrospective assessment of 80 such patients. Factors evaluated included etiology, associated conditions, time between amputations, late revisions, use of prostheses, and survival. In 63 patients both amputations were because of atherosclerosis. Of these patients, 86% were diabetic and 84% hypertensive. Peak incidence of the second amputation was during the 7th decade. Average time between amputations was 23 months. Forty-five (71%) of the atherosclerotic patients achieved some functional use of bilateral prostheses. The five patients employed at the time of the second amputation returned to work using prostheses. Average survival after the second amputation was 44 months for those deceased, and 64 months for those alive at the end of the study period. Nine patients had amputations because of various forms of injury, including one for sequential developments due to alcohol-related sensory loss. Eight of this group had a diagnosis of alcohol abuse of psychosis. Reasons for amputations included frostbite, burns, suicide attempt and sensory loss. Five achieved long-term but generally suboptimal prostheses use. The findings support the impression that most atherosclerotic bilateral BK amputees can use prostheses and that their survival and low rate of late stump revisions justify restorative efforts. Mental status was the major determinant of amputation and prostheses use among the non-atherosclerotic patients; discharge from psychiatric hospitals without adequate community support systems was probably contributory. Management and prevention require close collaboration between the rehabilitation, surgical, psychosocial, and public health disciplines.

Age Factors↗

Intense cold noxious stimulation of the rat hindpaw induces c-fos expression in lumbar spinal cord neurons.

This study evaluated Fos-like immunoreactivity in lumbar spinal cord neurons following intense cold stimulation and then the modifications induced by opioid administration. Under urethane anaesthesia, the rat's right foot was stimulated by holding it in a regulated temperature bath at 15, 10, 0, -10, -15, -17.5 or -20 degrees C. There was no or little Fos-like immunoreactivity in lumbar spinal cord neurons when the paw was at temperatures between 15 and -10 degrees C (0-5 Fos-like immunoreactive neurons/section). The threshold to induce consistent c-fos expression was -15 degrees C. From -15 to -20 degrees C, the number of Fos-like immunoreactive neurons increased with decreases in temperature. At -20 degrees C, Fos-like immunoreactive neurons were numerous in L3 and L4 segments, in laminae I-II (approximately 60 Fos-like immunoreactive neurons/section) and to a lesser extent in laminae V-VI (approximately 20). Almost no Fos-like immunoreactivity was present in laminae III-IV (< 5). At -20 degrees C, the number of Fos-like immunoreactive neurons increased with the duration of the stimulation. The number of Fos-like immunoreactive neurons induced by the cold stimulation temperatures was significantly decreased by pretreatment with 10 mg/kg s.c. morphine and moderately decreased by 5 mg/kg s.c. This effect was antagonized by the combined administration of morphine (10 mg/kg s.c.) and naloxone (2 mg/kg s.c.). Naloxone (2 mg/kg s.c.) significantly increased the number of Fos-like immunoreactive neurons induced by -20 degrees C as compared to saline-injected rats. This study showed that Fos-like immunoreactivity distribution is in good agreement with the location of neurons receiving noxious inputs and that the threshold to induce c-fos expression with cold was unexpectedly low at -15 degrees C. Taking into account, on the one hand, previous investigations using the same technique using noxious heat stimulation and, on the other hand, electrophysiological and psychophysiological studies using cold stimulation in animals and humans, our results suggest that Fos-like immunoreactivity induced by extremely cold stimulation, which seems to reproduce frostbite, may reflect activation of nociceptors due to vasoconstriction.

Animals↗

Intermediate-term results of retroperitoneoscopy-assisted cryotherapy for small renal tumours using multiple ultrathin cryoprobes.

OBJECTIVES: To evaluate outcome after retroperitoneoscopic cryotherapy for small renal tumours. METHODS: Fourteen patients underwent cryoablation performed with six ultrathin 1.5-mm cryoprobes. Retroperitoneoscopic access was used for any tumour location. A double freeze-thaw cycle was performed under simultaneous retroperitoneoscopic visual control and real-time ultrasound monitoring. RESULTS: Mean tumour size was 2.8 cm (range: 2.0-4.0), mean patient age was 68 yr (range: 49-83), and six left and eight right kidneys were treated. The mean operative time was 167 min (range: 120-200); mean blood loss was 93 ml (range: 0-300). Cryosurgery was successfully performed in all 14 patients, with 13 patients undergoing assisted retroperitoneoscopy and one patient, after previous open nephropexy, undergoing an open approach. Intraoperative biopsy specimens revealed renal cell cancer (RCC) in 10 (71%) patients. The only intraoperative complication was bleeding after removal of the cryoprobes in four (29%) patients, necessitating one intracorporeal stitch in each. Two (14%) of the first four patients presented postoperatively with superficial skin frostbite, which healed with conservative treatment. During mean follow-up of 21 mo (range: 2-42), 2 (14%) patients died from unrelated disease, and 12 patients remained without evidence of local recurrence. One patient with previous contralateral nephrectomy for RCC developed retroperitoneal lymph node metastasis on that side without recurrence in the cryoablated kidney. CONCLUSIONS: Retroperitoneoscopic cryotherapy using multiple ultrathin cryoprobes is safe and effective with encouraging oncologic results on intermediate-term follow-up. Prospective clinical trials and long-term oncologic data are needed to define its definitive role in treatment of renal tumours.

Aged↗

Biochemical background of ethanol-induced cold susceptibility.

The process of cooling is always associated with the depletion of energetic reserves and burning the ketone bodies covers the tissues' needs. Ethanol shows antiketonaemic effects changing the cellular redox potential, inhibiting beta-oxidation of fatty acids, stimulating the release of insulin and inhibiting the release of its antagonist. The aim of the study was to determine whether the cooling process of the organism in the presence of ethanol intoxication may be related to inhibition of the physiological mechanism of ketogenesis induced by hypothermia. The study involved the 67 autopsy cases from 1996 to 2002, in which the circumstances of death indicated the effects of overcooling. This was confirmed on the basis of the data from the Prosecutor's Offices. Then, the chromatograms of autopsy blood alcohol determinations were analyzed and the acetone levels recorded. The analysis supported the hypothesis that the severity of ketosis is inversely proportional to the blood ethanol concentration. Furthermore, it demonstrated that signs of prolonged cold exposure were less frequently observed in unsober persons (frostbites, gastric hemorrhages). Increased sensitivity of intoxicated individuals to cold may be related not only to the dilation of the peripheral vessels, inhibition of shivering thermogenesis caused by muscle relaxation, central nervous system depression and behavioral factors but also to the antiketonaemic effects of ethanol.

Acetone↗

Alpine climbing: injuries and illness.

Alpine climbing is a sport whose participants are at risk for a variety of injuries and illnesses. Climbers are venturing into the mountains and attempting routes with ever-increasing difficulty, and it is important to understand the injury and illness concerns of alpine climbers better. Alpine climbers are prone to injuries common to traditional mountaineers and more specialized sport rock climbers. Falls while climbing represent one of the more common causes of serious injury, although acute and chronic musculoskeletal injuries of the hands and extremities are also frequent afflictions. Alpine climbers are at risk for injuries and illness because of the mountain environment where they participate in their sport. Proper preparation for the cold is imperative to prevent frostbite and hypothermia. Worsening symptoms of headache or respiratory symptoms should always alert the alpine climber to possible altitude illness. Understanding the injuries common to the sport can allow providers to deliver the best medical care.

Accidental Falls↗

Pediatric hand injuries. Types and general treatment considerations.

Growth arrests may occur after fractures, burns, and frostbite injuries, but children generally have a better prognosis from most hand and forearm injuries than adults. Stiffness is less frequent, open wounds heal faster, remodeling of angular deformities may occur, and nerve recovery following repair is significantly better than adults. Parents should be aware of potential problems and the need for follow-up care for evaluating growth and scar development. Perhaps the greatest challenge for nurses as both parents and as members of society is the prevention of traumatic hand injuries. Children should be placed in seat belts when riding in motor vehicles, and toys and play areas should be geared toward the child's developmental age and abilities. Despite careful attention to a child's surroundings, some children will require emergency care for traumatic hand injuries. Health care workers must provide emotional support for parents who may feel guilty about their child's injury. They also must be prepared to give skilled clinical care guided by the child's development and the needs of the family members.

Child↗