Elevated procalcitonin as a diagnostic marker in meningococcal disease.

Patients with meningococcal disease who seek medical attention can create a diagnostic dilemma for clinicians due to the nonspecific nature of the disease's presentation. This study assesses the diagnostic accuracy of procalcitonin levels in the setting of meningococcal disease. Two emergency department cohorts (A and B) were studied between 2002 and 2005, during the current epidemic of serogroup B meningococcal disease in New Zealand. Cohort A consisted of 171 patients, all with confirmed meningococcal disease (84 children, 87 adults). Cohort B consisted of a large (n=1,524) consecutively recruited population of febrile patients who presented to the emergency department, 28 of whom had confirmed meningococcal disease. Within the meningococcal disease cohort (cohort A), the geometric mean procalcitonin level was 9.9 ng/ml, with levels being higher in children than in adults (21.6 vs. 4.6 ng/ml, p=0.01). The overall sensitivity of elevated procalcitonin, using a cutoff of 2.0 ng/ml in children and 0.5 ng/ml in adults, was 0.93 (95%CI: 0.88-0.96). Despite the higher cutoff level for paediatric patients, a trend towards greater sensitivity existed in children (0.96 vs. 0.90; p=0.08). Elevated procalcitonin was correlated with whole blood meningococcal load (r=0.50) and Glasgow Meningococcal Sepsis Prognostic Score (r=0.40). Within the cohort of patients who were febrile on presentation (cohort B), the specificity of elevated procalcitonin in meningococcal disease was 0.85 (95% CI: 0.83-0.87), the positive and negative likelihood ratios were 6.1 and 0.08, respectively, and the sensitivity of elevated procalcitonin (0.93; 95% CI: 0.76-0.99) was corroborated. Measurement of procalcitonin is a useful tool in patients with nonspecific febrile illnesses when the possibility of meningococcal disease is present. The diagnostic accuracy surpasses that of current early laboratory markers, allowing results to be used to guide decisions about patient management.

Mental health nursing and cultural diversity.

The focus of this article is on ethnic cultural difference. The establishment of a bi-cultural model of health care delivery has been a recent priority in New Zealand. Bi-culturalism has become an important concept for Maori and Pakeha (Europeans), working in partnership in the planning and implementation of mental health services in New Zealand. Adoption of the principles of respect and recognition of the uniqueness of different cultural identities, by nurses, has meant that clients who use mental health services in New Zealand are beginning to benefit from nursing care that is culturally competent.

Breath holding during the turn in competitive swimming.

Breath holding times were measured during competition and averaged 5.0 sec in the breaststroke events, 4.3 sec in freestyle, 3.7 sec in butterfly, and 3.3 sec in backstroke. These times represented approximately 30% of the total time of swimming breaststroke and freestyle races but only 20% of the time of backstroke and butterfly events. Pulmonary gas exchanges of O2 and CO2 were studied in eight male swimmers during the first turn after the start of a swim and during the third turn after continuous swimming. It was concluded that biomechanical considerations of optimizing a turn are in most circumstances not limited by the increased PCO2 and the decreased PO2 in the alveoli related to the brief period of breath holding. In turns which last longer than about 5.5 s, the swimmers may experience a strong urge to breathe. This "breaking point" sensation is brief and need not compromise the conclusion of a well-executed turn.

Velocity, stroke rate, and distance per stroke during elite swimming competition.

The mean velocity of 9 out of 10 women's events during the U.S. Olympic Swimming Trials was greater in 1984 as compared to 1976. Three of the 10 men's events showed improvement. In 9 out of these 12 events, the increased velocity was accounted for by increased distance per stroke (range, -3 to -13%). In the women's 100-m butterfly and 100-m backstroke, increased velocity was due solely to faster stroke rates. The finalists in each event were compared to those whose velocities were 3-7% slower. In almost all events and stroke styles, the finalists achieved greater distances per stroke than did the slower group. In the men's events increased distance per stroke was associated with decreased stroke rate, except in the backstroke, in which both were increased for the finalists. Although the faster women swimmers generally had greater distances per stroke, they were more dependent than men on faster stroke rates to achieve superiority. The profile of velocity for races of 200 m and longer indicated that as fatigue developed the distance per stroke decreased. The faster swimmers compensated for this change by maintaining or increasing stroke rate more than did their slower competitors. This study indicates that improvements and superiority in stroke mechanics are reflected in the stroke rate and distance per stroke used to swim a race.

Thermoregulatory and related responses to 2-deoxy-D-glucose administration in humans.

Hypothermia in humans during insulin-induced glucopenia has been largely attributed to impaired heat production. To further study the mechanism for hypothermia during glucoprivation six normal males were given 20-min intravenous infusions of 2-deoxy-D-glucose (2-DG), 50 mg/kg, a competitive inhibitor of glucose utilization. Oxygen and carbon dioxide exchange was measured to determine heat production by indirect calorimetry. Decreases in core temperature were initially associated with activation of mechanisms for heat loss such as sweating and hyperpnea 30-120 min after 2-DG infusion. Hypothermia persisted in spite of markedly increased plasma catecholamine, glucose, and free fatty acid levels from 60 to 180 min and increased heat production from 120 to 180 min after 2-DG infusion. Thus in contrast to the proposed mechanism for insulin-induced hypothermia, the hypothermia of 2-DG-induced glucoprivation is a consequence of increased heat loss and not of decreased heat production.

Relationships of stroke rate, distance per stroke, and velocity in competitive swimming.

Competitive swimmers were asked to swim at a constant velocity (v) for short distances. They wore a collar to which was attached a fine non-elastic steel wire. The wire passed over two wheels of a device attached to one end of the pool. One wheel generated an impulse for every cm of forward movement and another wheel produced an electrical signal which was directly proportional to V. Measurements of distance and time were begun at definable points in the stroke cycle and were discontinued at the end of a predetermined number of strokes. In all of the four competitive strokes, front and back crawl, butterfly, and breaststroke, the V increased as a result of increasing the stroke rate (S) and decreasing the distance per stroke (d/s). In the front crawl, the male and female swimmers who achieved the fastest V had the longest d/S at slow S. The faster male swimmers also had greater percent decrease of the d/S at their maximal V than did the less skilled persons. The back crawl was similar to the front crawl except that maximal S and V were less. Increases of V of the butterfly were related almost entirely to increases in S. Except at the highest V, d/S was decreased somewhat. In the breaststroke increased V was also associated with increasing S, but the d/S decreased much more than in the other stroke styles. Fluctuations of velocity during the stroke cycle were least in the front and back crawl (+/- 15--20%) and greatest in the butterfly and breaststroke (+ 45--50%). The results were compared to the S observed and the values for V and d/S calculated for a large group of swimmers competing in the 1976 U.S. Olympic Trials. The implications of the findings for coaching swimmers are discussed.

Quantitative analysis of the front crawl in men and women.

Body drag, D, and the overall mechanical efficiency of swimming, e, were measured from the relationship between extra oxygen consumption and extra drag loads in 42 male and 22 female competitive swimmers using the front crawl at speeds ranging from 0.4 to 1.2 m/s. D increased from 3.4 (1.9) kg at 0.5 m/s to 8.2 (7.0) kg at 1.2 m/s, with D of women (in brackets) being significantly less (P less than 0.05) than that of men. Mechanical efficiency increased from 2.9% at 0.5 m/s to 7.4% at 1.2 m/s for men, the values for women being somewhat greater than those for men. The ratio, D/e was shown to be identical to the directly measured energy cost of swimming one unit distance, V02/d, and was independent of the velocity up to 1.2 m/s. It averaged 52 and 37 l/km for men and women respectively (P less than 0.05). When corrected for body surface area the values were 27 and 22 l/km-m2 for men and women, respectively (P less than 0.05). The underwater torque, T, a measure of the tendency of the feet to sink, was 1.44 kg-m for men and 0.70 kg-m for women (P less than 0.05). VO2/d increased linearly with T for both men and women of similar competitive experience. However, the proportionality constant delta VO2/d-delta T was significantly less for competitive than noncompetitive swimmers. The analysis of the relationship VO2/d vs. T provides a valuable approach to the understanding of the energetics of swimming.

Summary of 58 cases of loss of consciousness during underwater swimming and diving.

It is well accepted that hyperventilation before breath hold swimming and diving makes it possible for a person to extend the time under water. Less well known is the fact that this maneuver can cause loss of consciousness due to hypoxia. This accident happens almost exclusively to males (56 cases). The most common age group was 16-20 years (range 12-33 years). All were known to be good swimmers or divers. Approximately 80% of the cases occurred in guarded pools. Thirty-five subjects survived the accident and of the twenty-three fatalities, there was only one good autopsy report. In this instance the findings were those associated with classical drowning preceded by hypoxia and hypercapnia. Breath holding experiments indicated that the times between loss of consciousness and death may be no longer than 2.5 minutes. The patterns associated with these cases suggest that those who are responsible for aquatic safety as supervisors or guards of pools could prevent most accidents by watching for young male swimmers who are practicing hyperventilation and underwater swimming in competition with themselves or with others.

Expiratory reserve volume and vital capacity of the lungs during immersion in water.

The effects of immersion by 5-cm increments on the expiratory reserve volume of the lungs (ERV) and on the vital capacity were studied in the sitting and supine positions. These effects were compared to those produced by continuous negative-pressure breathing when the subjects were in air and were counteracted by positive pressure breathing during immersion. The depth of immersion was also related to definable anatomic landmarks. In the sitting position about one-fourth of the decrease in the ERV was accounted for by the hydrostatic pressure of the water on the abdomen and the remainder by the pressure on the thorax. Immersion to the level of the spinous process of the seventh cervical vertebra was equivalent to 28 cmH2o continuous negative pressure breathing in air. In the supine position, a comparable value was 8 cmH2o. These observations agree well with those of others if differences in the levels of immersion are accounted for.

Tension decline during isometric contractions without visual cues.

Subjects tried to maintain 15%, 30% and 50% maximum voluntary contraction (MVC) of their handgrip for 60 sec and 70% MVC for 30 sec. When the subjects watched the tension record, they could maintain the contraction for the required time. However, without visual cues (uncued), the tests resulted in a tension decline. Ae-alpha t described the tension decline in the 15% tests, Be-beta t the 70% test, while the form in the 30% and 50% tests was Ae-alpha t + Be-beta t. In all cases alpha and/or beta were found to be dependent on the starting tension. The electrical activity obtained from surface electromyograms did not increase during the uncued tests which would be expected if muscle fatigue were involved in the tension decline. Instead the electrical activity was directly proportional to the decline in tension suggesting that the fall in tension was not due entirely to muscle fatigue. 15% MVC uncued tests in which fatigue is known not to be a factor also showed a tension decline. Precooling the hand in an attempt to alter sensory input produced no systematic change from the original uncued tests, indicating that sensory information from the hand was probably not a major factor in the tension decline. It is suggested that during the uncued tests the fast component of the tension decline may be related to a sensory adaptation involving the Golgi tendon organs. The slow component is due to forearm muscle fatigue which is related to the ischemia produced during the isometric contractions.