Unintentional Hypothermia Research Articles

Accidental hypothermia and related risk factors among trauma patients in prehospital setting

INTRODUCTION: Hypothermia is highly prevalent among trauma patients. If hypothermia is diagnosed and managed early, complications from hypothermia can be reduced. This study aimed to determine the prevalence of accidental hypothermia and related factors in prehospital trauma patients. MATERIAL AND METHODS: This is a single-center prospective observational study. From 2 to 16 November 2018, 132 trauma patients were selected by convenience sampling. To collect data, the patient’s core body temperature (CBT) and the temperature of the ambulance cabin were measured as the patient left the ambulance. A combination of observation and emergency medical technician records was used to identify factors influencing hypothermia onset or exacerbation. SPSS 16 was used to analyze the data using descriptive statistics and multiple logistic regression. A significance level of 5% was considered. RESULTS: It was calculated that 44.1% of prehospital trauma patients had accidental hypothermia. The predicting variables for accidental hypothermia in trauma patients were found to be level of consciousness (OR = 2.19, p < 0.049), pulse rate (OR = 1.04, p < 0.02), and ambient cabin temperature (OR = 1.32, p < 0.015). CONCLUSIONS: At the time of hospital admission, a significant number of trauma patients were hypothermic. This study emphasizes the need for identifying unintentional hypothermia in trauma patients early on during the pre-hospital stage.

Попередження інтраопераційної ненавмисної гіпотермії у пацієнтів із політравмою

Актуальність. Ненавмисна гіпотермія розвивається спонтанно як наслідок травми, хірургічного втручання та наркозу в результаті порушення відповідності теплопродукції тепловтрат і пригнічення компенсаторної терморегуляційної відповіді. Мета: вивчити ефективність способу корекції інтраопераційної ненавмисної гіпотермії з використанням системи конвекційного обігріву в пацієнтів із політравмою. Матеріали та методи. Обстежено 20 пацієнтів із політравмою, яким проводились ургентні оперативні втручання. Пацієнти були розділені на 2 групи: I — основна група (n = 10), в якій інтраопераційно проводилося активне зігрівання системою конвекційного обігріву WarmAir 135 (CSZ) з використанням ковдр для зігрівання в умовах операційної; II — контрольна група (n = 10) без використання конвекційного зігрівання. Вивчалася температура ядра тіла (Тсо): початково, через 30, 60 хвилин і наприкінці операції. Розраховувалися наступні показники: мінімальна (Тмін.) і максимальна (Тмакс.) температура, середня температура (Тср.), температурний діапазон (Тдіап. = Tмакс. – Тмін.). Результати. У всіх пацієнтів із політравмою та проведенням ургентних хірургічних втручань відзначається розвиток клінічно значущої ненавмисної гіпотермії. На етапі 60 хвилин інтраопераційного періоду Тсо була вірогідно вище в I групі (35,38 ± 0,28 °С) порівняно з пацієнтами II групи (34,70 ± 0,39 °С) (p < 0,05). Виявлено вірогідно вищий рівень середньої Тсо в I групі (35,53 ± 0,66 °С) порівняно з II групою (34,67 ± 1,74 °С) пацієнтів (p < 0,05). Діапазон температур, який являє собою різницю максимальної та мінімальної Тсо, був вірогідно нижче в I групі пацієнтів (1,36 ± 0,74 °С) порівняно з II групою (4,55 ± 1,11 °С) (p < 0,05). Висновки. Використання в комплексі інтенсивної терапії конвекційної системи зігрівання хоча й не дозволяє досягти вихідних значень Тсо, але попереджає прогресування поглиблення гіпотермії, ефективно забезпечуючи підтримку температурного гомеостазу у критичних пацієнтів із політравмою.

Perioperative Hypothermia-A Narrative Review.

Unintentional hypothermia (core temperature < 36 °C) is a common side effect in patients undergoing surgery. Several patient-centred and external factors, e.g., drugs, comorbidities, trauma, environmental temperature, type of anaesthesia, as well as extent and duration of surgery, influence core temperature. Perioperative hypothermia has negative effects on coagulation, blood loss and transfusion requirements, metabolization of drugs, surgical site infections, and discharge from the post-anaesthesia care unit. Therefore, active temperature management is required in the pre-, intra-, and postoperative period to diminish the risks of perioperative hypothermia. Temperature measurement should be done with accurate and continuous probes. Perioperative temperature management includes a bundle of warming tools adapted to individual needs and local circumstances. Warming blankets and mattresses as well as the administration of properly warmed infusions via dedicated devices are important for this purpose. Temperature management should follow checklists and be individualized to the patient’s requirements and the local possibilities.

Accidental perioperative hypothermia

The problem of perioperative hypothermia is still relevant. There are many reasons for that. One of them: a decrease in the patient’s body temperature during the operation often goes unnoticed, or is not perceived by medical staff as a serious complication. Perioperative unintentional hypothermia is a decrease in the patient’s core body temperature &lt;36 °C in the periods: 1 h before anesthesia, during surgery and 24 h after anesthesia. Usually a decrease in body temperature activates the hypothalamic mechanisms of thermoregulation, which provide first vasoconstriction, which reduces heat loss, and then the development of cold shivering (contractile thermogenesis) – heat production. Modern anesthetics affect the regulation of central temperature and lead to its reduction in the perioperative period. Unintentional intraoperative hypothermia accompanies many surgeries performed under general and regional anesthesia. It is perhaps the most important factor in the “triad of death” (hypovolemia, acidosis, hypothermia), which significantly increases the risk of complications, including: prolongation of the duration of action of anesthetics and muscle relaxants and the recovery period; increase in the volume of intraoperative blood loss; from the cardiovascular system complications up to fatal consequences; development of wound infection, increase in wound healing time; increasing the frequency of cold shivering, nausea and vomiting in the postoperative period. Thus, perioperative hypothermia leads to an increase in hospitalization and nosocomial mortality. An important role in the prevention and relief of perioperative hypothermia is played by the competence and motivation of the nurse to timely and effective action in all areas of the perioperative process using thermometry methods available in a specific medical institution (axillary, esophageal or tympanic), prevention of heat loss through the skin under the influence of the environment (room air temperature, operating and equipment), passive and active (convection systems) heating patients with a body temperature &lt;36 °C, rapid thawing and heating to 37 °C of allogeneic blood components. It is especially important during emergency operations, when it is necessary to start warming and temperature monitoring in the intensive care unit of the admission department.

Cuidados de enfermagem no período intraoperatório para manutenção da temperatura corporal

Objetivo: Descrever os cuidados de enfermagem para manutenção da temperatura corporal durante o intraoperatório. Método: Estudo descritivo,transversal, realizado em junho de 2015 no centro cirúrgico de um hospital no interior de São Paulo. Os dados foram coletados por meio de instrumentodesenvolvido para este estudo, o qual continha dados de caracterização sociodemográfica, clínica, cirúrgica e cuidados de enfermagem. Para todas as variáveis,foram realizadas análises descritivas. Resultados® Foram analisados os cuidados de enfermagem em 19 cirurgias, sendo a de maior incidência a colecistectomiavideolaparoscópica (26,3%), sob anestesia geral (52,6%). O tempo médio de duração da anestesia foi de 113 minutos. A hipotermia foi identificada em 84,2%dos pacientes no período pós-operatório. O método de aquecimento utilizado em todos os pacientes no intraoperatório foi do tipo cutâneo ativo, com infusãode solução aquecida por via endovenosa. Conclusão® A hipotermia não intencional é uma condição real no centro cirúrgico, causando prejuízos à recuperaçãodos pacientes. Sua prevenção está relacionada à realização de cuidados de enfermagem mais seguros e à redução de complicações pós-operatórias.

Unintentional hypothermia in the surgical patient. Old solutions to an old problem, or new solutions to an old problem?

Unintentional hypothermia in the surgical patient. Old solutions to an old problem, or new solutions to an old problem?

Influence of Vasoactive Infusions on Body Temperature During Off Pump Coronary Artery Bypass Grafting

Abstract Introduction Unintentional hypothermia in patients undergoing off pump coronary artery bypass grafting (OPCABG) under general anesthesia (GA) is a known complication. The wide sternotomy wound as well as low ambient operating room temperature further promotes heat loss. The changes in temperature could further be affected by the use of various vasoactive drugs by affecting the thermoregulatory response. This study is aimed to detect the temperature changes and the influence of vasoactive infusions on the temperature in the patients undergoing OPCABG under GA. Aims The main purpose of this article is to assess the core and skin temperature changes during OPCABG surgery and to assess the effect of vasoactive infusion used intraoperatively on the core temperature Settings and Design Single center, nonrandomized, open label, observational study. Methods and material After informed consent and ethical clearance from institutional review board, 151 adult patients undergoing elective OPCABG surgeries under GA were included in the study. A common anesthetic protocol and warming strategy was used in all patients. The core temperature measured with a nasopharyngeal probe and the skin temperature measured at the palmar surface of the right index finger were recorded at induction, at 30 minutes intervals thereafter, and at end surgery. The demographic variables and the duration of surgery were also recorded. The type and dose of vasoactive agents used intraoperatively were also recorded. The study population was divided post hoc into groups and subgroups for further analysis. Results All the patients showed a decrease in core temperature at end surgery. The temperature changes showed an initial exponential decrease in the first hour followed by a gradual decrease subsequently. The peripheral temperature showed a gradual increase from induction to end surgery. The temperature gradients showed a linear decrease with the core temperature and peripheral skin temperature reaching equilibrium at end surgery. The study population was divided into four groups depending on the type of vasoactive drugs received intraoperatively: vasoconstrictor (V), vasodilator (D), mixed vasoconstrictor and vasodilator (M), and no vasoactive drugs (N) group. The patients in the vasoconstrictor group had a higher core temperature at end surgery when compared with vasodilator group. Conclusions OPCABG under GA results in decrease in core temperature. The decrease in temperature is exponential in the initial 1 hour followed by a more gradual decrease. The temperature changes are possibly affected by the vasoactive drugs used intraoperatively. The effect of vasoactive drugs on core temperature is higher when used during the initial exponential decrease in temperature. However, further adequately powered randomized controlled trials may be required to establish these findings.

Retrospective Analysis of Esophageal Heat Transfer for Active Temperature Management in Post-cardiac Arrest, Refractory Fever, and Burn Patients.

Core temperature management is an important aspect of critical care; preventing unintentional hypothermia, reducing fever, and inducing therapeutic hypothermia when appropriate are each tied to positive health outcomes. The purpose of this study is to evaluate the performance of a new temperature management device that uses the esophageal environment to conduct heat transfer. De-identified patient data were aggregated from three clinical sites where an esophageal heat transfer device (EHTD) was used to provide temperature management. The device was evaluated against temperature management guidelines and best practice recommendations, including performance during induction, maintenance, and cessation of therapy. Across all active cooling protocols, the average time-to-target was 2.37 h and the average maintenance phase was 22.4 h. Patients spent 94.9% of the maintenance phase within ±1.0°C and 67.2% within ±0.5°C (574 and 407 measurements, respectively, out of 605 total). For warming protocols, all of the patient temperature readings remained above 36°C throughout the surgical procedure (average 4.66 h). The esophageal heat transfer device met performance expectations across a range of temperature management applications in intensive care and burn units. Patients met and maintained temperature goals without any reported adverse events.

Surgery and magnetic resonance imaging increase the risk of hypothermia in infants.

Maintaining normothermia is a tenet of neonatal care. However, neonatal thermal care guidelines applicable to intra-hospital transport beyond the neonatal intensive care unit (NICU) and during surgery or magnetic resonance imaging (MRI) are lacking. The aim of this study is to determine the proportion of infants normothermic (36.5-37.5°C) on return to NICU after management during surgery and MRI, and during standard clinical care in both environments. Sixty-two newborns requiring either surgery in the operating theatre (OT) (n = 41) or an MRI scan (n = 21) at the Royal Children's Hospital (Melbourne) NICU were prospectively studied. Core temperature, along with cardiorespiratory parameters, was continuously measured from 15 min prior to leaving the NICU until 60 min after returning. Passive and active warming (intra-operatively) was at clinician discretion. The study reported 90% of infants were normothermic before leaving NICU: 86% (MRI) and 93% (OT). Only 52% of infants were normothermic on return to NICU (relative risk (RR) 1.75; 95% confidence interval (CI) 1.39-2.31; number needed to harm (NNH) 2.6). Between departure from the NICU and commencement of surgery, core temperature decreased by mean 0.81°C (95% CI 0.30-1.33; P = 0.0001, analysis of variance), with only 24% of infants normothermic when surgery began (P < 0.0001; RR 3.80 (95% CI 2.33-6.74); NNH 1.5). After an MRI, infants were a mean 0.41°C (95% CI 0.16-0.67) colder than immediately before entering the scanner (P = 0.001, analysis of variance), with only 43% being normothermic (P = 0.003; RR 2.11 (95% CI 1.35-3.74); NNH 2.1). Unintentional hypothermia is a common occurrence during surgery in the OT and MRI in neonates, indicating that evidence-based warming strategies to prevent hypothermia should be developed.

Thermal suit in preventing unintentional intraoperative hypothermia during general anaesthesia: a randomized controlled trial.

Unintentional perioperative hypothermia causes serious adverse effects to surgical patients. Thermal suit (T-Balance® ) is an option for passive warming perioperatively. We hypothesized that the thermal suit will not maintain normothermia more efficiently than conventional cotton clothes when also other preventive procedures against unintentional hypothermia are used. One hundred patients were recruited to this prospective, randomized trial. They were allocated to the Thermal Suit group or a Control group wearing conventional hospital cotton clothes. All patients received our institution's standard treatment against unintentional hypothermia including a warming mattress, a forced-air upper body warming blanket and a warming device for intravenous fluids. Eardrum temperature was measured pre-operatively. In the operating room and post-anaesthesia care unit temperatures were measured from four locations: oesophagus, left axilla, dorsal surface of the left middle finger and dorsum of the left foot. The primary outcome measure was temperature change during robotic-assisted laparoscopic radical prostatectomy. The temperatures of 96 patients were analysed. There was no difference in mean core temperatures, axillary temperatures or skin temperatures on the finger between the groups. Only foot dorsum temperatures were significantly lower in the Thermal Suit group. Intraoperative temperature changes were similar in both groups. In the post-anaesthesia care unit temperature changes were minimal and they did not differ between the groups. Provided that standard preventive procedures in maintaining normothermia are effective the thermal suit does not provide any additional benefit over conventional cotton clothes during robotic-assisted laparoscopic radical prostatectomy.

Preventing perioperative hypothermia

PREVENTING unplanned or unintentional perioperative hypothermia has been a quality measure of The Joint Commission and the Centers for Medicare and Medicaid Services since 2009, when the Surgical Care Improvement Project (SCIP) went into effect.1 Research shows that hypothermia can lead to a host of

Management of drowning and accidental hypothermia: a national survey of the Major Trauma Centres in England

Background Unintentional drowning and accidental hypothermia are important causes of death worldwide, and may occur simultaneously. In the case of severe accidental hypothermia with cardiac arrest, recent guidelines recognised extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass as safe and effective rewarming techniques, with survival rates of approximately 50%. We assessed whether the Major Trauma Centres (MTCs) in the UK had protocols for the management of hypothermia and drowning, and whether they had access to ECMO and/or bypass.

MicroRNA‐155 potentiates the inflammatory response in hypothermia by suppressing IL‐10 production

Therapeutic hypothermia is commonly used to improve neurological outcomes in patients after cardiac arrest. However, therapeutic hypothermia increases sepsis risk and unintentional hypothermia in surgical patients increases infectious complications. Nonetheless, the molecular mechanisms by which hypothermia dysregulates innate immunity are incompletely understood. We found that exposure of human monocytes to cold (32°C) potentiated LPS-induced production of TNF and IL-6, while blunting IL-10 production. This dysregulation was associated with increased expression of microRNA-155 (miR-155), which potentiates Toll-like receptor (TLR) signaling by negatively regulating Ship1 and Socs1. Indeed, Ship1 and Socs1 were suppressed at 32°C and miR-155 antagomirs increased Ship1 and Socs1 and reversed the alterations in cytokine production in cold-exposed monocytes. In contrast, miR-155 mimics phenocopied the effects of cold exposure, reducing Ship1 and Socs1 and altering TNF and IL-10 production. In a murine model of LPS-induced peritonitis, cold exposure potentiated hypothermia and decreased survival (10 vs. 50%; P < 0.05), effects that were associated with increased miR-155, suppression of Ship1 and Socs1, and alterations in TNF and IL-10. Importantly, miR-155-deficiency reduced hypothermia and improved survival (78 vs. 32%, P < 0.05), which was associated with increased Ship1, Socs1, and IL-10. These results establish a causal role of miR-155 in the dysregulation of the inflammatory response to hypothermia.

Modelos lineales de temperatura corporal en el paciente postquirúrgico

Introduction and objectives: unintentional hypothermia is a situation in which nursing has to be trained for recognition and control. Our objectives were to evaluate the proportion of patients arriving in situations of hypothermia (temperature <36 ° C) and to study the behavior of body temperature in the post-anesthesia care unit.Methods: the measurement was carried out by infrared electronic tympanic thermometer. The contrast arithmetic test was performed by T tests. When variables contained more than two categories, we used the one-way ANOVA. Models were constructed with linear and logistic regression.Results: 85.26% of patients had hypothermia. The average admission temperature of patients treated with combined anesthesia was significantly lower than that of those treated with local or general. Both in the univariate and in multivariate models using linear regression, the temperature measured at 90 minutes was the most correlated with the temperature at discharge (coefficient of determination R2 = 0.69, P <0.001).Discussion: we found a high proportion of patients with hypothermia (body temperature below 36 ° C) on admission (85.26%). We found no predictor for arrival hypothermia despite combined anesthetized patients were admitted with an average temperature measuring less than those treated with local or general (one-way ANOVA p <.05). We consider a minimum stay of 90 minutes for proper control of the temperature variable in a non docketed empirical overheating

The Turkish Anaesthesiology and Reanimation Society Guidelines for the prevention of inadvertent perioperative hypothermia.

The Turkish Anaesthesiology and Reanimation Society Guidelines for the prevention of inadvertent perioperative hypothermia.

Left ventricular systolic dysfunction in a patient with accidental hypothermia: a case report

IntroductionHypothermia is a relatively rare condition, and the effects of unintentional hypothermia on the heart are not known.Case presentationThis report describes the case of an 88-year-old Japanese man found in a coma and presenting with heart failure associated with hypothermia. He experienced sinus arrest, junctional rhythm and left ventricular systolic dysfunction with prolonged ejection time. With rewarming and treatment of his heart failure, he completely recovered over a period of two weeks.ConclusionProlonged ejection time might be a characteristic finding in hypothermia.

Does Clinically Relevant Temperature Change miRNA and Cytokine Expression in Whole Blood?

Unintentional hypothermia is a well-described risk factor for death and complications after elective and emergency surgery. The molecular mechanisms by which hypothermia exerts its detrimental effects are not well understood. Differences in cytokine production and the overall cell function have been reported under hypothermic conditions. We investigated the effect of a range of clinically relevant temperatures on cytokine production and microRNA (miRNA) expression in a whole-blood model. We found that there was a wide variation in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-10 production among different subjects, ranging from low to high TNF-α producers. The intersubject variation can also be found on the transcriptional level: high producers had higher upregulation of TNF-α messenger RNA than intermediate and low producers. This variation in TNF-α was reproducible in each individual. Temperature seems to modulate TNF-α production among these different groups. miRNA expression was modulated by temperature. miRNA-181a might control, or be a part of the mechanism which controls, TNF-α production. However, an analysis of whole-leukocyte RNA does not allow the investigation of mechanisms in a specific leukocyte subpopulation such as monocytes, because these changes may be concealed by miRNA expression changes in the other leukocyte subsets. In conclusion, TNF-α, IL-6, and IL-10 production is highly variable among different persons, but temperature affects the expression of miRNAs, which may consequently alter the production of TNF-α.

Patient Warming Excess Heat

Patient warming has become a standard of care for the prevention of unintentional hypothermia based on benefits established in general surgery. However, these benefits may not fully translate to contamination-sensitive surgery (i.e., implants), because patient warming devices release excess heat that may disrupt the intended ceiling-to-floor ventilation airflows and expose the surgical site to added contamination. Therefore, we studied the effects of 2 popular patient warming technologies, forced air and conductive fabric, versus control conditions on ventilation performance in an orthopedic operating room with a mannequin draped for total knee replacement. Ventilation performance was assessed by releasing neutrally buoyant detergent bubbles ("bubbles") into the nonsterile region under the head-side of the anesthesia drape. We then tracked whether the excess heat from upper body patient warming mobilized the "bubbles" into the surgical site. Formally, a randomized replicated design assessed the effect of device (forced air, conductive fabric, control) and anesthesia drape height (low-drape, high-drape) on the number of bubbles photographed over the surgical site. The direct mass-flow exhaust from forced air warming generated hot air convection currents that mobilized bubbles over the anesthesia drape and into the surgical site, resulting in a significant increase in bubble counts for the factor of patient warming device (P < 0.001). Forced air had an average count of 132.5 versus 0.48 for conductive fabric (P = 0.003) and 0.01 for control conditions (P = 0.008) across both drape heights. Differences in average bubble counts across both drape heights were insignificant between conductive fabric and control conditions (P = 0.87). The factor of drape height had no significant effect (P = 0.94) on bubble counts. Excess heat from forced air warming resulted in the disruption of ventilation airflows over the surgical site, whereas conductive patient warming devices had no noticeable effect on ventilation airflows. These findings warrant future research into the effects of forced air warming excess heat on clinical outcomes during contamination-sensitive surgery.

Unintentional hypothermia: implications and management of the post-operative patient

Inadvertent hypothermia is not uncommon in the immediate post-operative period and is associated with impairment and abnormalities in various organs and systems that can lead to adverse outcomes. While there is much research to support the negative effects of hypothermia, often the focus is aimed towards minimizing heat loss in the peri and intra-operative period, however patients continue to lose heat post operatively, which can contribute to both short and long-term problems. Veterinary nurses have a pivotal role to play in minimizing such losses, with the main objectives consisting of detecting and recording post-operative hypothermia, as well as minimizing further heat loss and correcting any temperature deficits. Simple nursing interventions including careful positioning of post-operative patients away from draughty areas of the ward, frequent monitoring and recording of body temperature, and a combination of passive and active rewarming techniques can prove extremely beneficial to the recovery of hypothermic patients in the postoperative period. Using the recommendations highlighted within this article it may be possible to minimize the physiological effects of hypothermia as well as to improve patient comfort during this important recovery phase.

Avoiding Unintentional Hypothermia During Prosthetic Joint Replacement Surgery

Fig 1. Efficacy of Solution C for disinfection of hospital equipment. Background/Objectives: Hypothermia during the intraoperative period is associated with an increased risk of developing a surgical site infection. Despite using both a forced warm air jacket preoperatively and blanket during surgery, 36% of prosthetic joint replacement patients did not achieve normothermia during the intraoperative period. Due to the surgeon's concern that the forced air motorwould increase room contaminants, the forced air blanket was not turned on until the patient's skin preparation and draping was accomplished, often leading to unintentional hypothermia. Beginning in September 2011, an underbody disposable waterbased warming pad was added to the operating room (OR) table to be used in conjunction with the forced air modalities. Objectives: The objective of this study was to determine if using an underbody warming device, in addition to the forced warm air modalities would increase the proportion of patients achieving and maintaining normothermia during surgery. Methods: From May to September 2010, the baseline period, intraoperative temperatures were obtained from anesthesia records of 50 patients who underwent joint replacement surgery. The underbody disposable water-based warming pad was implemented for joint replacement surgeries in September 2011. From September 2011 to January 2012, the post intervention period, anesthesia records of 56 patients were reviewed to determine the first and last intraoperative temperatures, as well as the highest and lowest temperature. Temperatures were taken using either a bladder probe or an esophageal probe. Results: During the baseline period 13/50 (26%) of patients were normothermic the entire time they were in the OR, as compared to 29/56 (52%) of patients during the post intervention period (p1⁄40.0067). Thirty-six percent (18/50) of the patients were hypothermic for the duration of the surgical procedure during the baseline period, while there were only 12% (7/56) in the post intervention period (p1⁄40.0044). When comparing the last temperature taken in the operating room; 25/50 (50%) of the patients were normothermic in the baseline period, but 46/56 (82%) were normothermic in the post intervention period (p1⁄40.0004). Conclusions: Conclusions: Using the underbody disposable water based warming pad together with preoperative and intraoperative forced warm air warming modalities increased and maintained patients' body temperature throughout the intraoperative period. These results have supported continued utilization of the underbody warming pad. The adoption of this new warming system contributes to collaborative efforts to reduce postoperative infections in prosthetic joint replacement patients.