Effects of the thermal conditions of the dressing room and bathroom on physiological responses during bathing

Advantages of bystander-performed conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest presumably caused by drowning in Japan: a propensity score-matching analysis using an extended nationwide database

OBJECTIVES

This study aimed to determine whether the association between conventional bystander cardiopulmonary resuscitation (BCPR) and better outcomes in drowning-associated out-of-hospital cardiac arrest (OHCA) differs between young and older people or between non-medical and medical drowning in Japan.

DESIGN

Observational study.

SETTING

This study used data from the Japanese Fire and Disaster Management Agency databases.

PARTICIPANT

Of the 504 561 OHCA cases recorded in the nationwide database between 2016 and 2019, 16 376 (3.2%) were presumably caused by drowning.

MAIN OUTCOME MEASURE

The main outcomes were a 1-month neurological prognosis defined as cerebral performance category 1 or 2 and 1-month survival as measures.

RESULT

The incidence of drowning as a presumed cause of OHCA was high in the winter and the middle-aged and older generations in Japan. However, OHCA caused by drowning in the younger generation frequently occurs in the summer. Furthermore, younger patients had higher incidences of bystander-witnessed cardiac arrest (22.0%), BCPR provision (59.3%) and arrest in outdoor settings (54.0%) than middle-aged and older generations (5.9%, 46.1% and 18.7% respectively). If the patient was younger or the arrest was accidental, the conventional BCPR group had better neurological outcomes than the compression-only BCPR group (95% CI of adjusted OR, 1.22 to 12.2 and 1.80 to 5.57, respectively). However, in the case of middle-aged and older generations and medical categories, there was no significant difference in outcomes between the two types of BCPR. This conventional group's advantage was maintained even after matching.

CONCLUSION

Conventional bystander CPR yielded a higher neurologically favourable survival rate than compression-only BCPR for OHCA caused by drowning if the patient was younger or the arrest was non-medical. Conventional CPR education for citizens who have the chance to witness drownings should be maintained.

Blood pressure, pulse rate, and skin temperature during hot-water bathing in real-world settings among community-dwelling older adults: the HEIJO-KYO Study

BACKGROUND

Home hot-tub bathing substantially increases drowning mortality rates among older adults in Japan. Previous laboratory studies on hemodynamic responses during hot-tub bathing have been inconsistent depending on the thermal conditions. Furthermore, real-world hemodynamic changes that occur during bathing remain poorly understood. This study investigated the association between individual thermal states and hemodynamic parameters during hot-tub bathing among community-dwelling older adults.

METHODS

In this cross-sectional study conducted between January 2016 and April 2019, which involved 1,479 older adults (median [range] age, 68 [40-90] years), skin temperature on the abdominal surface was measured every minute. Ambulatory blood pressure and pulse rate were recorded at 15-min intervals for 24 h. Participants underwent simultaneous living room temperature measurements in their homes, and the time and methods of bathing were recorded. Associations between skin temperature and hemodynamic parameters during bathing and between the pre-bath living room temperature and in-bath maximum proximal skin temperature were evaluated using mixed-effects and linear regression models, respectively.

RESULTS

A 1 °C increase in skin temperature was significantly associated with a 2.41 mmHg (95% confidence interval [CI]: 2.03-2.79) increase in systolic blood pressure and a 2.99 bpm (95% CI: 2.66-3.32) increase in pulse rate, after adjusting for potential confounders, including age, sex, body mass index, antihypertensive medication use, dyslipidemia, diabetes, and living room and outdoor temperatures. Significant interactions were not observed between sex and skin temperature in relation to systolic blood pressure and pulse rate (P = 0.088 and 0.490, respectively). One standard deviation lower living room temperature before bathing was significantly associated with a 0.41 °C (95% CI: 0.35-0.47) higher maximum skin temperature during bathing.

CONCLUSIONS

Our findings suggest that pre-bath cold exposure may increase the skin temperature during hot-tub bathing, possibly resulting in excessive hemodynamic changes. This provides a framework for future interventions that utilize pre-bath thermal conditions and bathing environments to prevent bath-related deaths.

A comprehensive survey analysis focusing on the effect of living literacy on residential environment and health recognition under COVID-19 in Japan

Appropriate knowledge and actions of residents in housing are expected to reduce health effects, defined as "living literacy." With the spread of COVID-19 and the diversification of lifestyles, a quantitative evaluation of a comprehensive model that includes living literacy in the housing environment is required. In this study, the author conducted two web-based surveys of approximately 2000 different households in Japan during the summer of 2020 and winter of 2021, and a statistical analysis based on the survey results. As a result, ventilation by opening windows was observed as a new resident behavior trend under COVID-19. In addition, structural equation modeling using the survey samples confirmed the certain relationship between living literacy and subjective evaluation of the indoor environment and health effects in both periods.

Environmental Challenges in the Home for Ageing Societies: a Comparison of Sweden and Japan

Sweden and Japan are developed welfare countries facing serious societal and public health challenges due to demographic ageing. The objective of the present study was to provide a background to environmental challenges in the home, related to demographic ageing. Specific aims were to compare: 1) demography and household composition 2) physical housing stocks 3) indoor accidents and 4) housing adaptations between the two countries. Descriptive analyses were conducted using secondary data sources. Demographic ageing is projected to accelerate faster in Japan compared to Sweden, with overall lower fertility rates expected in Japan. In 2050, 39% of the Japanese population is projected to be aged 65 years or older, compared to 23% of the Swedish population. The Swedish ordinary housing stock was markedly older than the Japanese housing stock, with almost 80% of the dwellings built before 1980, while in Japan about 65% were built after 1980. High occurrences of fatal indoor accidents were noted in both countries, but for different reasons. In Sweden, falls was the dominant cause of fatal accidents among older people, while in Japan, in addition to falls, drowning and suffocation caused most of the fatal accidents. Housing adaptations were less frequent in Japan compared to Sweden, and the procedure for evaluating, granting and carrying out housing adaptations appeared to be more complicated in Japan. To decrease the occurrence of indoor accidents, identifying and removing "risk barriers" could be instrumental. In both countries, large-scale efforts are imperative to improve the housing situation for the ageing population.

Clinical Characteristics of Stroke Occurring while Bathing

BACKGROUND

Stroke can occur during any human activity. Although cardiac arrests or drowning accidents while bathing have been studied extensively, there are few studies focusing on stroke occurring while bathing. The objectives of this study were to evaluate the clinical characteristics of stroke occurring while bathing and the association between stroke and drowning accidents.

METHODS

Clinical data prospectively acquired between January 2011 and December 2015 on 1939 patients with stroke (1224 cerebral infarctions [CIs], 505 intracerebral hemorrhages [ICHs], and 210 subarachnoid hemorrhages [SAHs]) were reviewed to identify patients who sustained a stroke while bathing. The ratio of bathing-related strokes to strokes occurring during other activities was evaluated. Moreover, the demographics of these 2 groups were compared in each stroke type.

RESULTS

Among the 1939 patients, 78 (CI, 32; ICH, 28; and SAH, 18) sustained a stroke while bathing. The ratio of bathing to other activities in the SAH group was the highest (8.6%), followed by the ICH group (5.5%), whereas that in the CI group was the lowest (2.6%). Regardless of stroke type, only a minority of patients were found to have collapsed inside the bathtub.

CONCLUSIONS

The higher ratio of bathing in hemorrhagic strokes may indicate that there is a small risk of hemorrhagic stroke while bathing in vulnerable subjects. This retrospective study did not establish a causal relationship between bathing and stroke nor identify risk factors, which means that future prospective studies are warranted. The finding that the great majority of bathing-related stroke patients were found to have collapsed outside the bathtub suggests that the involvement of stroke in drowning accidents in the bathtub may be small.

Physiology Of Drowning: A Review

Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.

Effects of room temperature on physiological and subjective responses during whole-body bathing, half-body bathing and showering

The effects of bathroom thermal conditions on physiological and subjective responses were evaluated before, during, and after whole-body bath (W-bath), half-body bath (H-bath) and showering. The air temperature of the dressing room and bathroom was controlled at 10 degrees C, 17.5 degrees C, and 25 degrees C. Eight healthy males bathed for 10 min under nine conditions on separate days. The water temperature of the bathtub and shower was controlled at 40 degrees C and 41 degrees C, respectively. Rectal temperature (Tre), mean skin temperature (Tsk), blood pressure (BP), heart rate (HR), body weight loss and blood characteristics (hematocrit: Hct, hemoglobin: Hb) were evaluated. Also, thermal sensation (TS), thermal comfort (TC) and thermal acceptability (TA) were recorded. BP decreased rapidly during W-bath and H-bath compared to showering. HR during W-bath was significantly higher than for H-bath and showering (p < 0.01). The double products due to W-bath during bathing were also greater than for H-bath and showering (p < 0.05). There were no distinct differences in Hct and Hb among the nine conditions. However, significant differences in body weight loss were observed among the bathing methods: W-bath > H-bath > showering (p < 0.001). W-bath showed the largest increase in Tre and Tsk, followed by H-bath, and showering. Significant differences in Tre after bathing among the room temperatures were found only at H-bath. The changes in Tre after bathing for H-bath at 25 degrees C were similar to those for W-bath at 17.5 degrees C and 10 degrees C. TS and TC after bathing significantly differed for the three bathing methods at 17.5 degrees C and 10 degrees C (TS: p < 0.01 TC: p < 0.001). Especially, for showering, the largest number of subjects felt "cold" and "uncomfortable". Even though all of the subjects could accept the 10 degrees C condition after W-bath, such conditions were intolerable to half of them after showering. These results suggested that the physiological strains during H-bath and showering were smaller than during W-bath. However, colder room temperatures made it more difficult to retain body warmth after H-bath and created thermal discomfort after showering. It is particularly important for H-bath and showering to maintain an acceptable temperature in the dressing room and bathroom, in order to bathe comfortably and ensure warmth.

Effects of bathing and hot footbath on sleep in winter

The effects of daily bathing and hot footbath (immersion of feet in hot water) in winter on the sleep behavior of nine healthy female volunteers were studied. Subjects were assigned to three sleep conditions: sleep after bathing (Condition B), sleep after hot footbath (Condition F), and sleep without either treatment (Control). Polysomnograms (consisting of electroencephalograph, electrooculograph, and electromyograph) were obtained, and body movements during sleep were measured while monitoring both the rectal and skin temperatures of subjects. In addition, subjective sleep sensations were obtained with a questionnaire answered immediately by the subjects on awakening. The rectal temperature increased by approximately 1.0 degree C under Condition B, but this elevation was not observed under Condition F compared with Control. In contrast, the respective increases in the mean skin temperature of participants subjected to bathing and hot footbath were greater than those of Control, although these temperature differences became negligible 2 h after subjects went to bed. The sleep onset latency was shortened under both conditions compared with Control. Body movements during the first 30 min of sleep in Control were greater than under the other conditions. Rapid eye movement (REM) sleep decreased under Condition B compared with Condition F, and stage 3 was greater under the latter condition compared with Control. As such, the subjective sleep sensations were better under the two treatment conditions. These results suggest that both daily bathing and hot footbath before sleeping facilitates earlier sleep onset. A hot footbath is especially recommendable for the handicapped, elderly, and disabled, who are unable to enjoy regular baths easily and safely.

Estimation of thermal sensation during varied air temperature conditions

Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.