Monitoring and thermal management

Hypoglycemia is an early, independent predictor of bacteremia and in-hospital death in patients with cirrhosis

BACKGROUND AND AIMS

Bacteremia is a common cause of death in patients with cirrhosis and early antimicrobial therapy can be life-saving. Severe liver disease impairs glucose metabolism such that hypoglycemia may be a presenting sign of infection in patients with cirrhosis. We explored this association using granular retrospective data.

METHODS

We conducted a case-control analysis from 1 January 2008 to 31 December 17 in the University of Pennsylvania Health System. We identified the first blood culture results from all cirrhosis hospitalizations and obtained detailed vital sign and laboratory data in the 24-72 h prior to culture results. We used multivariable logistic regression to develop models predicting blood culture positivity and in-hospital mortality. We repeated these analyses restricted to normothermic individuals. Restricted cubic splines were used to model nonlinearity in the glucose variable.

RESULTS

We identified 1274 cirrhosis admissions with blood culture results (52.7% positive). In adjusted models, minimum glucose 24-72 h prior to blood culture result date was a significant predictor of blood culture positivity. In particular, glucose levels below 100 mg/dL significantly increased the probability of subsequent positive blood culture (e.g. odds ratio 1.89 for 50 mg/dL vs. 100 mg/dL, P = 0.004). This relationship persisted when restricting the cohort to normothermic individuals. Glucose levels <100 mg/dL in patients with bacteremia were also positively associated with in-hospital mortality.

CONCLUSIONS

Early hypoglycemia is predictive of subsequently documented bacteremia and in-hospital mortality in patients with cirrhosis, even among normothermic individuals. In patients without other overt signs of infection, low glucose values may serve as an additional data point to justify early antibiosis.

Warming of blood and intravenous fluids using low-power infra-red light-emitting diodes

Non-contact warming of blood and intravenous (IV) fluids with temperature drop compensation is an unmet clinical need till now, for management of hypothermia in patients with urgent requirement of blood. Currently available technologies provide wet warming or dry warming with direct contact using hot water or with a hot plate, respectively. These conventional technologies need disposable cartridges to be used in conjunction with the warmer. The warmed fluids lose their temperature when passing through long IV lines and fails in its purpose at low flow rates. In this paper, a distributed non-contact warming method is introduced using infra-red radiations. The method incorporates a bag warming unit and an inline cartridge unit. Bag warming unit provides uniform distribution of infra-red thermal energy liberated from low cost infra-red light emitting diodes (IR LEDs) in horizontal and vertical planes of the fluid carrying bag. An inline cartridge, through which the IV line passes, reduces the drop in temperature just before the transfusion site using a cluster of IR LEDs. As per the In Vitro tests are carried out in to establish the safety and efficacy, the bag warming unit steadily rises the temperature to attain the cut off value with a temperature rise coefficient of 0.7 °C/min and the inline cartridge warms the fluid within 10 min at a thermal transfer rate of more than 1.5 °C/min. The fluid temperature is uniformly distributed within a narrow range of 36-38 °C. When the inline warmer is powered on, the drop-in temperature is reduced to zero for flow up to 5 ml/min. For flow rates more than 8 ml/min, the temperature drop is reduced more than half. For massive transfusion range, the temperature of the fluid remains within 38.5 ± 1.2 °C for flow rates in the range of 100-1500 ml/min.

The Relationship of Postoperative Delirium and Unplanned Perioperative Hypothermia in Surgical Patients

PURPOSE

The purpose of this study was to investigate associations between postoperative delirium (POD) and unplanned perioperative hypothermia (UPH) among adults undergoing noncardiac surgery.

DESIGN

A retrospective, exploratory design was used.

METHODS

A retrospective, exploratory study was conducted using electronic medical record data abstracted from a purposive convenience sample of adult patients undergoing noncardiac surgery from January 2014 to June 2017.

FINDINGS

The analyzed data set included 22,548 surgeries, of which 9% experienced POD. Logistic regression indicated that American Society of Anesthesiologists (ASA) class was the strongest predictor of POD (χ² = 1,207.11, df = 4, inclusive of all ASA class terms). A significant relationship between UPH and POD (χ² = 54.94, df = 4, inclusive of all UPH terms) and a complex relationship among UPH, patient age, ASA class, and POD were also found.

CONCLUSIONS

Results support a relationship between UPH and POD. Notably, there is also a complex relationship in the noncardiac surgery population among UPH, age, ASA class, and POD. Preliminary understanding of this relationship is based on the pathophysiological response to surgical stress. Further research is indicated.

The effectiveness of air-free warming systems on perioperative hypothermia in total hip and knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Perioperative hypothermia is a common and serious complication during surgery. Different warming systems are used to prevent perioperative hypothermia. However, there have been no previous meta-analyses of the effectiveness of air-free warming systems on perioperative hypothermia in patients undergoing joint arthroplasty.

METHODS

We systematically searched PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases to collect randomized controlled trials (RCTs) from inception to August 2018. These RCTs compared the effects of air-free warming with forced-air (FA) warming system in patients undergoing joint arthroplasty. Postoperative temperature, core temperature during surgery, thermal comfort, blood loss and incidence of shivering and hypothermia were analyzed.

RESULTS

A total of 287 patients from 6 clinical studies were included in the analysis. In summary, there was no significant difference in the postoperative temperature (WMD -0.043, 95% CI -0.32 to 0.23, P = .758) between the air-free warming and FA warming groups. No statistical difference (WMD 0.058, 95% CI -0.10 to 0.22, P = .475) was found in core temperatures at 0 minutes during surgery between the air-free warming and FA warming groups. Furthermore, there was no statistical difference in thermal comfort, blood loss or incidence of shivering and hypothermia between the air-free warming and FA warming groups.

CONCLUSIONS

Air-free warming system was as effective as FA warming system in patients undergoing joint arthroplasty.

Maintaining intraoperative normothermia reduces blood loss in patients undergoing major operations: a pilot randomized controlled clinical trial

Background

Inadvertent intraoperative hypothermia (core temperature < 36 °C) is a common but preventable adverse event. This study aimed to determine whether active intraoperative warming reduced bleeding in patients undergoing major operations: open thoracic surgery and hip replacement surgery.

Methods/Design

The study was a pilot, prospective, parallel two-arm randomized controlled trial. Eligible patients were randomly allocated to two groups: passive warming (PW), with application of a cotton blanket (thermal insulation), or active warming (AW), with a forced-air warming system. The primary endpoint was intraoperative blood loss, and secondary endpoints were surgical-site infection, cardiovascular events, and length of stay in the post-anesthesia care unit, intensive care unit, and hospital.

Results

Sixty-two patients were enrolled. Forced-air active warming maintained intraoperative normothermia in all AW subjects, whereas intraoperative hypothermia occurred in 21/32 (71.8%) of PW patients (p = 0.000). The volume of blood loss was more in the PW group (682 ± 426 ml) than in the AW group (464 ± 324 ml) (p < 0.021), and the perioperative hemoglobin value declined more in the PW group (28.6 ± 17.5 g/L) than in the AW group (21.0 ± 9.9 g/L) (p = 0.045). However, there were no difference in other clinical outcomes between two groups.

Conclusion

Intraoperative active warming is associated with less blood loss than passive warming in open thoracic and hip replacement operations in this pilot study.

Trial registration

This trial was registered with Clinicaltrials.gov (Identifier: NCT02214524) on 27 August 2014.

Impact of hypothermia on implementation of CPAP for neonatal respiratory distress syndrome in a low-resource setting

BACKGROUND

Neonatal hypothermia is widely associated with increased risks of morbidity and mortality, but remains a pervasive global problem. No studies have examined the impact of hypothermia on outcomes for preterm infants treated with CPAP for respiratory distress syndrome (RDS).

METHODS

This retrospective analysis assessed the impact of hypothermia on outcomes of 65 neonates diagnosed with RDS and treated with either nasal oxygen (N = 17) or CPAP (N = 48) in a low-resource setting. A classification tree approach was used to develop a model predicting survival for subjects diagnosed with RDS.

FINDINGS

Survival to discharge was accurately predicted based on three variables: mean temperature, treatment modality, and mean respiratory rate. None of the 23 neonates with a mean temperature during treatment below 35.8°C survived to discharge, regardless of treatment modality. Among neonates with a mean temperature exceeding 35.8°C, the survival rate was 100% for the 31 neonates treated with CPAP and 36.4% for the 11 neonates treated with nasal oxygen (p<0.001). For neonates treated with CPAP, outcomes were poor if more than 50% of measured temperatures indicated hypothermia (5.6% survival). In contrast, all 30 neonates treated with CPAP and with more than 50% of temperature measurements above 35.8°C survived to discharge, regardless of initial temperature.

CONCLUSION

The results of our study suggest that successful implementation of CPAP to treat RDS in low-resource settings will require aggressive action to prevent persistent hypothermia. However, our results show that even babies who are initially cold can do well on CPAP with proper management of hypothermia.

The impact of perioperative hypothermia on plastic surgery outcomes: a multivariate logistic regression of 1062 cases

BACKGROUND

Perioperative hypothermia has been associated with increased rates of infection, prolonged recovery time, and coagulopathy.

OBJECTIVES

The authors assessed the impact of hypothermia on patient outcomes after plastic surgery and analyzed the impact of prewarming on postoperative outcomes.

METHODS

The medical charts of 1062 patients who underwent complex plastic surgery typically lasting at least 1 hour were reviewed. Hypothermia was defined as a temperature at or below 36°C. Postoperative complication data were collected for outcomes including infection, delayed wound healing, seroma, hematoma, dehiscence, deep venous thrombosis, and overall wound problems. Odds ratios (ORs) were estimated from 3 multivariate logistic regression models of hypothermia and one model of body contouring procedures that included prewarming as a parameter.

RESULTS

Perioperative hypothermia was not a significant predictor of wound problems (OR = 0.83; P = .28). In the stratified regression model, hypothermia did not significantly impact wound problems. The regression model measuring the interaction between hypothermia and operating time did not show a significantly increased risk of wound problems. Prewarming did not significantly affect perioperative hypothermia (P = .510), and in the model of body contouring procedures with prewarming as a categorical variable, massive weight loss was the most significant predictor of wound complications (OR = 2.57; P = .003). Prewarming did not significantly affect outcomes (OR = 1.49; P = .212).

CONCLUSIONS

Based on univariate and multivariate models in our study, mild perioperative hypothermia appears to be independent of wound complications. LEVEL OF EVIDENCE 4: Risk.

Evidence utilisation project: Management of inadvertent perioperative hypothermia. The challenges of implementing best practice recommendations in the perioperative environment

AIMS

The prevention of inadvertent perioperative hypothermia (IPH) remains an important issue in perioperative healthcare. The aims of this project were to: (i) assess current clinical practice in the management of IPH and (ii) promote best practice in the management of IPH in adult operating theatres.

METHODS

This project from August 2010 to March 2012 utilised a system of audit and feedback to implement best practice recommendations. Data were collected via chart audits against criteria developed from best practice recommendations for managing IPH. Evidence-based best practices, such as consistent temperature monitoring and patient warming, were implemented using multifaceted interventions.

RESULTS

Perioperative records for 73 patients (baseline) and 72 patients (post-implementation) were audited. Post-implementation audit showed an increase in patients with temperatures >36°C admitted to the post-anaesthetic care unit (PACU) (8%) and discharged from PACU (28%). The percentage of patients receiving preoperative temperature monitoring increased (38%); however, low levels of intraoperative monitoring remained (31% of patients with surgery of 30 min or longer duration). Small increases were found in patient warming of 5% intraoperatively and 8% postoperatively. Preoperative warming was not successfully implemented during this phase of the project.

CONCLUSION

Temperature monitoring, warming and rates of normothermia improved; however, barriers to best practice of IPH management were experienced, which negatively impacted on the project. Further stages of implementation and audit were added to further address IPH management in this department.

Thoracotomy for lung lesion does not affect the accuracy of esophageal temperature

BACKGROUND

There are several sites for measuring body temperature. Correct reading of core temperature is imperative for patients undergoing major operations under anesthesia. In certain situations, the sites of measurement may be close to the surgical area, and thus the measurement is easily prejudiced by the influence environment. We hypothesized that the body temperature, if monitored in the esophagus, would be lower than obtained from the tympanic membrane during thoracotomy for lung pathology under general anesthesia.

MATERIALS AND METHODS

The study involved 32 patients, of American Society of Anesthesiologists (ASA) physical status I or II, who were to undergo elective thoracotomy for lung disorders. General anesthesia was induced with fentanyl, propofol, and rocuronium and maintained with sevoflurane in oxygen. The tympanic membrane probe was placed prior to when general anesthesia was administered, and the esophageal probe was inserted after administration of general anesthesia. Both the individualized temperatures were recorded at 5-minute intervals, and were compared at each change of surgical situation.

RESULTS

The tympanic membrane temperature was higher than esophageal temperature after initiation of one-lung ventilation (OLV) with statistical significance. The magnitude of decrease in temperature between two individualized temperatures, as compared from start of OLV, was greater in tympanic membrane temperature, especially at 30 minutes after OLV (p < 0.02, difference = -0.09 ± 0.22) and at the time point of the lowest temperature (p = 0.002, difference = -0.14 ± 0.24). There was no clinical difference of situation found (difference > 0.5°C) in the measuring sequences.

CONCLUSION

The accuracy of esophageal temperature seemed not to be affected during thoracotomy for lung lesion, in comparison with that of tympanic temperature. From clinical viewpoints, the monitoring of esophageal temperature could be more reliable in such surgical situation.

A randomised controlled trial of the resistive heating blanket versus the convective warming system for preventing hypothermia during major abdominal surgery

We compared resistive heating (RH) and upper-body convective warming (CW) in 70 patients (RH 33, CW 31, 6 excluded) undergoing major abdominal surgery. The effect of RH was not inferior to that of CW for the time-weighted average core temperature, and the lower limit of 95% CW was greater than -0.5 degrees C. Resistive heating showed no inferiority in maintaining core temperature compared with convective warming.

Perioperative hypothermia in the pediatric population: a quality improvement project

There are limited data in the pediatric population regarding the incidence of, risk factors for, and means to prevent perioperative hypothermia. The Institute for Healthcare Improvement Model for quality improvement (QI) methodology was used to bundle the most effective techniques to prevent hypothermia. A multidisciplinary QI team was assembled with the goal to decrease the incidence of perioperative hypothermia by 50%. The baseline incidence of hypothermia was determined and causes identified using a flowchart and a cause-and-effect diagram. Pareto charts were formed and opportunities to decrease the incidence of perioperative hypothermia were trialed. The baseline incidence of hypothermia was 8.9%. Implementation of a standardized temperature management bundle in the operating rooms decreased the incidence to 4.2%. The QI methodology was useful to bundle the most effective techniques to prevent hypothermia, resulting in standardized perioperative care and a sustained reduction in the incidence of perioperative hypothermia.

Influence of hydatidiform mole follow-up setting on postmolar gestational trophoblastic neoplasia outcomes: a cohort study

OBJECTIVE

To assess the influence of hydatidiform mole (HM) management setting (reference center versus other institutions) on gestational trophoblastic neoplasia (GTN) outcomes.

METHODS

This cohort study included 270 HM patients attending Botucatu Trophoblastic Diseases Center (BTDC, São Paulo State University, Brazil) between January 1990 and December 2009 (204 undergoing evacuation and entire postmolar follow-up at BTDC and 66 from other institutions [OIs]). GTN characteristics and outcomes were analyzed and compared according to HM management setting. The confounding variables assessed included age, gravidity, parity, number of abortions and HM type (complete or partial). Postmolar GTN outcomes were compared using Mann-Whitney's test, chi2 test or Fisher's exact test.

RESULTS

Postmolar GTN occurred in 34 (34/204 = 16.7%) BTDC patients and in 27 (27/66 = 40.9%) of those initially treated in other institutions. BTDC patients showed lower metastasis rate (5.8% vs. 48%, p = 0.003) and lower median FIGO (2002) score (2.00 [1.00, 3.00] vs. 4.00 [2.00, 7.00], p = 0.003]. Multiagent chemotherapy to treat postmolar GTN was required in 2 BTDC cases (5.9%) and in 8 OI cases (29.6%) (p = 0.017). Median time interval between molar evacuation and chemotherapy onset was shorter among BTDC patients (7.0 [6.0, 10.0] vs. 10.0 [7.0, 16.0], p = 0.040).

CONCLUSION

BTDC patients showed GTN characteristics indicative of better prognosis. This underscores the importance of GTD specialist centers.

Patient warming excess heat: the effects on orthopedic operating room ventilation performance

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Hip arthroscopy and hypothermia

PURPOSE

To determine the incidence of and factors that contribute to the development of hypothermia during hip arthroscopic surgery.

METHODS

An analytic observational study was carried out in a cohort of 73 consecutive patients. All patients underwent hip arthroscopy for the treatment of femoroacetabular impingement. The patients' core temperature (esophageal) was measured throughout the surgery. Relevant information was collected on the patients (age, gender, body mass index, blood pressure) and on the procedure (volume and temperature of saline solution, pressure of fluid pump, surgery time, room temperature). The corresponding statistical analysis was performed with Stata 10.0 (StataCorp, College Station, TX), by use of a repeated-measures generalized estimating equations model.

RESULTS

The patients' mean age was 33 years, and there were 39 female and 34 male patients. The mean body mass index was 23.9; systolic blood pressure, 97.5 mm Hg; and diastolic blood pressure, 52.2 mm Hg. The incidence of hypothermia below 35°C (95°F) was 2.7%. The multivariate statistical analysis of the results showed a direct relation between hypothermia and surgery time of more than 120 minutes (P < .001). There was an inverse relation between core body temperature and surgery time (P < .001), with a drop of 0.19°C/h (32.342°F/h). Of the patients, 68.22% had a decrease in temperature of more than 0.5°C (32.9°F) until the end of surgery. There was also a direct relation between core body temperature and saline solution temperature (P < .001), body mass index (P < .01), and diastolic blood pressure (P < .03).

CONCLUSIONS

The incidence of hypothermia below 35°C (95°F) in patients who underwent hip arthroscopy for the treatment of femoroacetabular impingement is 2.7%. The factors that contribute toward the development of hypothermia during hip arthroscopic surgery are prolonged surgery time, low body mass index, low blood pressure during the procedure, and low temperature of the arthroscopic irrigation fluid.

Intraoperative warming and post-operative cognitive dysfunction after total knee replacement

BACKGROUND

Post-operative cognitive dysfunction (POCD) can affect 30% of orthopedic surgery patients. We hypothesized that perioperative temperature has an impact on POCD.

METHODS

We included 150 patients over 65 years of age scheduled for total knee replacement under spinal anesthesia. They were randomized to receive standard care (sheet cover) or active warming. Neurocognitive assessment (11 subtests) was performed pre-operatively and at day 4 (three subtests) and 3 months (10 subtests). A control group of 55 nonsurgical patients took the same tests at equivalent times. POCD was defined as an individual score decrease of more than 2 standard deviations (SDs) below the baseline on at least two subtests or 2 SDs in the combined z-score, in both cases using control-adjusted changes.

RESULTS

Tympanic temperature declined below 35 °C in 88% of standard-care patients; 25.3% of warmed patients had a temperature ≥36 °C. On day 4, 3.2% of standard-care patients and 19.4% of warmed patients had POCD (P=0.0058). At 3 months, there were no between-group differences (standard care, 14.3%; warmed, 6.5%) (P=0.2440).

CONCLUSIONS

Perioperative warming was associated with a higher incidence of cognitive dysfunction at 4 days after total knee replacement in patients >65 years of age.

A systematic review of the effectiveness of cutaneous warming systems to prevent hypothermia

AIMS

To retrieve and critique recent randomised trials of cutaneous warming systems used to prevent hypothermia in surgical patients during the intraoperative period and to identify gaps in current evidence and make recommendations for future trials.

BACKGROUND

Hypothermia affects up to 70% of anaesthetised surgical patients and is associated with several significant negative health outcomes.

DESIGN

Systematic review using integrative methods.

METHODS

We searched CINAHL, EMBASE, Cochrane Register of Controlled Trials and Medline databases (January 2000-April 2007) for recent reports on randomised controlled trials of cutaneous warming systems used with elective patients during the intraoperative period. Inclusion criteria. We included randomised control trials examining the effects of cutaneous warming systems used intraoperatively on patients aged 18 years or older undergoing non-emergency surgery. Studies published in English, Spanish or Portuguese with a comparison group that consisted of either usual care or active cutaneous warming systems without prewarming were reviewed.

RESULTS

Of 193 papers initially identified, 14 studies met the inclusion criteria. There was moderate evidence to indicate that carbon-fibre blankets and forced-air warming systems are equally effective and that circulating-water garments are most effective for maintaining normothermia during the intraoperative period. Few trials reported costs.

CONCLUSIONS

Carbon-fibre blankets and forced-air warming systems are effective and circulating-water garments may be preferable. Future research should measure the direct and indirect costs associated with competing systems.

RELEVANCE TO CLINICAL PRACTICE

Nurses can use this review to inform their selection of warming interventions in perioperative nursing practice. They can also assess other factors such as nursing workload, staff training and equipment maintenance, which should be incorporated into future research.

Hipotermia no período intra-operatório em pacientes submetidos a cirurgias eletivas

OBJETIVO: Analisar a temperatura corporal do paciente submetido a cirurgia eletiva no período intra-operatório. MÉTODOS: Para a coleta de dados elaborou-se um instrumento que foi submetido à validação aparente e de conteúdo e a amostra foi constituída de 70 pacientes. As variáveis mensuradas foram: temperatura e umidade da sala de cirurgia e temperatura corporal do paciente em diferentes momentos do período intra-operatório. RESULTADOS: Em relação à temperatura corporal dos pacientes observou-se que no final do procedimento anestésico-cirúrgico a média foi de 33,6º C. A temperatura média da sala na chegada dos pacientes foi de 24,6º C e na quarta hora de procedimento anestésico-cirúrgico foi de 22,4ºC. Houve correlação estatisticamente significante e positiva entre as variáveis mensuradas. CONCLUSÃO: Os resultados apontaram a necessidade de implementação de intervenções efetivas para a prevenção da hipotermia e, neste cenário, a atuação do enfermeiro é crucial para a melhoria da assistência prestada ao paciente cirúrgico.

Warming of intravenous fluids prevents hypothermia during off-pump coronary artery bypass graft surgery

OBJECTIVE

Even mild perioperative hypothermia (34 degrees -36 degrees C) can cause numerous adverse outcomes, including morbid cardiac events, coagulopathy with increased blood loss, and a decreased resistance to surgical wound infection. The purpose of this study was to evaluate the effect of fluid warming on preventing hypothermia during off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

A prospective randomized clinical study.

SETTING

A tertiary care university hospital.

PARTICIPANTS

Forty patients undergoing OPCAB procedures.

INTERVENTIONS

Patients were randomized into control (n = 20) and Hotline (n = 20) groups. In the Hotline group, all intravenous fluids were warmed to 41 degrees C by using 2 Hotline (SIMS Inc, Rockland, MD) systems. All patients (control and Hotline groups) were managed with standardized institutional practice by using a combination of increased ambient operating room temperature (to 25 degrees C) and the use of a warmed water mattress (38 degrees C).

MEASUREMENTS AND MAIN RESULTS

Temperatures were recorded every hour after the induction of anesthesia at the pulmonary artery, nasopharynx, rectum, and bladder. In the Hotline group, temperatures were maintained or increased. In the control group, temperatures gradually decreased. There were no significant differences between the 2 groups in hemodynamic parameters, serum catecholamine concentrations, duration of intensive care unit stay, or duration of ward stay.

CONCLUSIONS

The results show that the warming of intravenous fluids by using the Hotline system prevents decreases in systemic temperatures during OPCAB surgery.

The Influence of Stellate Ganglion Transcutaneous Electrical Nerve Stimulation on Signal Quality of Pulse Oximetry in Prehospital Trauma Care

BACKGROUND

Accurate monitoring of the peripheral arterial oxygen saturation has become an important tool in the prehospital emergency medicine. This monitoring requires an adequate plethysmographic pulsation. Signal quality is diminished by cold ambient temperature due to vasoconstriction. Blockade of the stellate ganglion can improve peripheral vascular perfusion and can be achieved by direct injection or transcutaneous electrical nerve stimulation (TENS) stimulation. We evaluated whether TENS on the stellate ganglion would reduce vasoconstriction and thereby improve signal detection quality of peripheral pulse oximetry.

METHODS

In our study, 53 patients with minor trauma who required transport to the hospital were enrolled. We recorded vital signs, including core and skin temperature before and after transport to the hospital. Pulse oximetry sensors were attached to the patient's second finger on both hands. TENS of the stellate ganglion was started on one side after the beginning of the transport. Pulse oximeter alerts, due to poor signal detection, were recorded for each side separately.

RESULTS

On the hand treated with TENS we detected a significant reduction of alerts compared to the other side (mean alerts TENS 3.1 [1-15] versus control side 8.8 [1-28] P < 0.05). The duration of dropouts was shorter as well (mean duration TENS 77 [16-239] s versus control side 333 [78-1002] s).

CONCLUSION

The data indicate that blockade of the stellate ganglion with TENS improves signal quality of pulse oximeters in the prehospital setting.

Comparison of forced-air warming and electric heating pad for maintenance of body temperature during total knee replacement

We conducted a randomised controlled trial to compare the efficacy of forced‐air warming (Bair Hugger^™, Augustine Medical model 500/OR, Prairie, MN) with that of an electric heating pad (Operatherm 202, KanMed, Sweden) for maintenance of intra‐operative body temperature in 60 patients undergoing total knee replacement under combined spinal‐epidural anaesthesia. Intra‐operative tympanic and rectal temperatures and verbal analogue score for thermal comfort were recorded. There were no differences in any measurements between the two groups, with mean (SD) final rectal temperatures of 36.8 (0.4) °C with forced‐air warming and 36.9 (0.4) °C with the electric pad. The heating pad is as effective as forced‐air warming for maintenance of intra‐operative body temperature.

Thermal management of the patient: where does the patient lose and/or gain temperature?

PURPOSE OF REVIEW

Anesthesia inhibits normal thermoregulatory control, leading to perioperative hypothermia or allowing therapeutic hypothermia. During the last decade many studies have shown the effects of anesthesia on thermoregulation. As a consequence many active warming and cooling devices are available to manipulate patients' core temperature. This review focuses on new findings in the field of temperature management.

RECENT FINDINGS

Thermal management of patients has improved tremendously in recent years. Many outcome studies have shown adverse effects of perioperative hypothermia, as well as beneficial effects of therapeutic hypothermia after out-of-hospital cardiac arrest and brain trauma. However, inducing hypothermia is limited by physiologic thermoregulatory responses. Small reductions in core temperature lead to vasoconstriction and shivering, effectively hindering hypothermia. Thus prevention of vasoconstriction and shivering have become major goals during induction of therapeutic hypothermia. All anesthetics, opioids and sedatives lower the vasoconstriction and shivering threshold, thus allowing hypothermia. However, these drugs have side effects, such as respiratory depression, sedation and nausea. Several drugs, alone or in combination, lower the shivering threshold while causing minimal or no side effects.

SUMMARY

Anesthesia affects thermoregulatory control and leads to perioperative hypothermia. The prevention of perioperative hypothermia improves patient's outcome. Therapeutic hypothermia can be induced and also improves outcome in certain conditions.

Temperature--the forgotten vital sign

OBJECTIVE

To improve the measurement of core body temperature in the resuscitation room.

METHOD

This work was undertaken in the Emergency Department (ED) of a large District General Hospital. The clinical notes for all admissions to the resuscitation suite during a 2 month period were reviewed to establish the frequency of temperature measurement. Following a simple educational program, performance was re-audited using the same methodology.

RESULTS

Of the first cohort 13.4% had had their temperature recorded. This improved to 71.6%.

CONCLUSIONS

The measurement of body temperature in the resuscitation room is important as hypothermia has profound effects on the cardiovascular, pulmonary, neurological and haemostatic systems. Clinical audit highlights poor current performance and enables improvement of practice through simple education.

Morbidity and mortality related to anaesthesia outside the operating room

PURPOSE OF REVIEW

The purpose of this review is to provide information related to morbidity and mortality associated with anaesthesia outside the operating room.

RECENT FINDINGS

There is an increasing demand for anaesthesia at remote locations. Because of its specific characteristics, resulting from the location and the patient, morbidity and mortality rates of remote location anaesthesia could differ from conventional operating room anaesthesia. However, no studies are currently available. On the basis of morbidity and mortality data from conventional operating room anaesthesia, we reached some important conclusions with regard to the safety of anaesthesia outside the operating room. A well-equipped anaesthesia machine, standard monitoring (electrocardiogram, oxygen saturation and non-invasive blood pressure), trained personnel and adequate planning should be standard for all out of the operating room procedures. When all these are in place, the incidence of morbidity or mortality should be comparable to that of anaesthesia provided in the operating room.

SUMMARY

There is certainly a need for studies concerning morbidity and mortality at remote location anaesthesia. Special care for the prevention of hypothermia should be given to those patients undergoing long-lasting diagnostic procedures, e.g. magnetic resonance imaging scans or cardiological investigations.

Technological and Medical Advances: Implications for Health Psychology

Behavioral telehealth, health informatics, organ and tissue transplantation, and genetics are among the areas that have been affected by advances in technology and medicine. These areas illustrate the opportunities and the challenges that new developments can pose to health psychologists. Each area is discussed with respect to implications for practice, research, public policy, and education and training: recommendations are provided.