Inadvertent Hypothermia After Procedural Sedation and Analgesia in a Cardiac Catheterization Laboratory: A Prospective Observational Study

Perioperative temperature monitoring for patient safety: A period prevalence study of five hospitals

BACKGROUND

Monitoring body temperature is essential for safe perioperative care. Without patient monitoring during each surgical phase, alterations in core body temperature will not be recognised, prevented, or treated. Safe use of warming interventions also depends on monitoring. Yet there has been limited evaluation of temperature monitoring practices as the primary endpoint.

OBJECTIVE

To investigate temperature monitoring practices during all stages of perioperative care. We examined what patient characteristics are associated with the rate of temperature monitoring, along with clinical variables such as warming intervention or exposure to hypothermia.

DESIGN

An observational period-prevalence study over seven days across five Australian hospitals.

SETTINGS

Four metropolitan, tertiary hospitals and one regional hospital.

PARTICIPANTS

We selected all adult patients (N = 1690) undergoing any surgical procedure and any mode of anaesthesia during the study period.

METHODS

Patient characteristics, perioperative temperature data, warming interventions and exposure to hypothermia were retrospectively collected from patient charts. We describe the frequencies and distribution of temperature data at each perioperative stage, including adherence to minimum temperature monitoring based on clinical guidelines. To examine associations with clinical variables, we also modelled the rate of temperature monitoring using each patient's count of recorded temperature measurements within their calculated time interval from anaesthetic induction to postanaesthetic care unit discharge. All analyses adjusted 95% confidence intervals (CI) for patient clustering by hospital.

RESULTS

There were low levels of temperature monitoring, with most temperature data clustered around admission to postanaesthetic care. Over half of patients (51.8%) had two or less temperatures recorded during perioperative care and one-third (32.7%) had no temperature data at all prior to admission to postanaesthetic care. Of all patients that received active warming intervention during surgery, over two-thirds (68.5%) had no temperature monitoring recorded. In our adjusted model, associations between clinical variables and the rate of temperature monitoring often did not reflect clinical risk or need: rates were decreased for those with greatest operative risk (American Society of Anesthesiologists Classification IV: rate ratio (RR) 0.78, 95% CI 0.68-0.89; emergency surgery: RR 0.89, 0.80-0.98), and neither warming interventions (intraoperative warming: RR 1.01, 0.93-1.10; postanaesthetic care unit warming: RR 1.02, 0.98-1.07) nor hypothermia at postanaesthetic care unit admission (RR 1.12, 0.98-1.28) were associated with monitoring rate.

CONCLUSIONS

Our findings point to the need for systems-level change to enable proactive temperature monitoring over all phases of perioperative care to enhance patient safety outcomes.

REGISTRATION

Not a clinical trial.

The effects of active warming on perioperative inadvertent hypothermia in patients undergoing vitreoretinal surgery under local anesthesia

Purpose:

Perioperative inadvertent hypothermia (PIH) is the decrease in core temperature below 36°C. We aimed to assess whether PIH develops in patients operated under local anesthesia (ULA) for vitreoretinal surgery in the operating room and investigate active warming efficacy.

Methods:

Seventy-two patients were divided into two groups: Group 1 contained unwarmed patients (n = 36), and Group 2, warmed patients (n = 36). The core temperatures, heart rate (HR), and mean arterial pressure (MAP) of the patients were measured at the beginning of surgery, after 20 min, 40 min, 1 h, at the end of the operation, and during the postoperative period.

Results:

PIH incidence was 44.6% in Group 1, whereas no hypothermia was observed in Group 2. Patient temperatures at 20 min (P = 0.001), 40 min (P < 0.001), 1 h (P < 0.001), the end of the operation (P < 0.001), and the postoperative period (P < 0.001) were significantly higher in Group 2 than in Group 1. Patient HRs at the end of the operation and during the postoperative period were significantly lower in Group 2 (P = 0.005) than in Group 1 (P < 0.001). The intraoperative 40^th (P = 0.044) and 60^th (P < 0.001) minutes, end of operation (P < 0.001), and postoperative MAP (P < 0.001) values of Group 1 were significantly higher than those of Group 2.

Conclusion:

PIH may develop in patients operated ULA, especially with a low ambient temperature. Actively warming may help prevent the harmful effects of PIH.

Cost-effectiveness of forced air warming during sedation in the cardiac catheterisation laboratory

AIM

The aim of this study was to determine the cost-effectiveness of forced air warming (FAW) during sedation in a cardiac catheterisation laboratory.

BACKGROUND

Forced air warming improves thermal comfort in comparison with standard care. It is not known whether the extra costs required for FAW are good value.

DESIGN

Cost-effectiveness analysis alongside a randomized controlled trial conducted in 2016-2017.

METHODS

A cost-effectiveness analysis was undertaken using Monte Carlo simulations from input distributions to estimate costs and effects associated with using FAW to reduce risk of thermal discomfort for patients receiving sedation in a cardiac catheterisation laboratory. A range of willingness to pay threshold values were tested with results plotted on a cost-effectiveness acceptability curve. Costs were calculated in Australian currency ($AUD).

RESULTS

Estimated total costs were $5.21 (SD 3.26) higher per patient for FAW in comparison to standard care. Estimated probability of success (rating of thermal comfort) was 0.16 (0.06) higher for FAW. Forced air warming becomes more likely to result in a net benefit than standard care at a willingness to pay threshold of $34.

CONCLUSION

Forced air warming could be considered cost-effective for procedures performed with sedation in a cardiac catheterisation laboratory if the extra cost of an incremental gain in thermal comfort is less than the decision maker's willingness to pay for it. Therefore, those responsible for decision-making regarding use of FAW in the cardiac catheterisation laboratory can use results of our model to decide if it represents good value for their organisation.

Dexmedetomidine-propofol vs ketamine-propofol anaesthesia in paediatric and young adult patients undergoing device closure procedures in cardiac catheterisation laboratory: An open label randomised trial

Background and Aims:

Several drug combinations have been tried in patients with acyanotic congenital heart disease (ACHD) undergoing transcatheter device closure in the cardiac catheterisation laboratory (CCL). Adequate sedation, analgesia, akinesia, cardiorespiratory stability, and prompt recovery are key requirements. Ketamine with propofol is used for this purpose. Dexmedetomidine carries a shorter recovery time. This study compared dexmedetomidine–propofol (DP) with ketamine–propofol (KP) in patients in the CCL.

Methods:

This was an open label randomised trial at a CCL over a 2-year period from August 2012 to August 2014. Fifty-six paediatric and 44 young adults with ACHD underwent device closure and were randomised to receive DP or KP. The primary outcome studied was time to regain full consciousness, airway and motor recovery.

Results:

Baseline characteristics were similar in the study groups. In the DP arm as compared to the KP arm, the time to recovery of consciousness (mean ± SD) was significantly faster in both paediatric patients [30 ± 15 vs. 58 ± 13 min (P < 0.001)] and in young adult patients [22 ± 10 vs. 35 ± 12 min (P < 0.001)]. There was significantly faster motor recovery also (mean ± SD) [paediatric: 25 ± 05 vs. 40 ± 14 (P < 0.001); young adult: 10 ± 05 vs. 22 ± 10 min (P < 0.001)].

Conclusion:

Procedural anaesthesia with DP in paediatric and young adult patients with ACHD undergoing device closure in the CCL resulted in faster recovery of consciousness and motor recovery compared to KP.

Forced air warming during sedation in the cardiac catheterisation laboratory: a randomised controlled trial

OBJECTIVE

Forced air warming (FAW) during general anaesthesia is a safe and effective intervention used to reduce hypothermia. The objective of this study was to determine if FAW reduces hypothermia when used for procedures performed with sedation in the cardiac catheterisation laboratory.

METHODS

A parallel-group randomised controlled trial was conducted. Adults receiving sedation in a cardiac catheterisation laboratory at two sites were randomised to receive FAW or usual care, which involved passive warming with heated cotton blankets. Hypothermia, defined as a temperature less than 36°C measured with a sublingual digital thermometer after procedures, was the primary outcome. Other outcomes were postprocedure temperature, shivering, thermal comfort and major complications.

RESULTS

A total of 140 participants were randomised. Fewer participants who received FAW were hypothermic (39/70, 56% vs 48/69, 70%, difference 14%; adjusted RR 0.75, 95% CI=0.60 to 0.94), and body temperature was 0.3°C higher (95% CI=0.1 to 0.5, p=0.004). FAW increased thermal comfort (63/70, 90% vs51/69, 74% difference 16%, RR 1.21, 95% CI=1.04 to 1.42). The incidence of shivering was similar (3/69, 4% vs 0/71 0%, difference 4%, 95% CI=-1.1 to 9.8). One patient in the control group required reintervention for bleeding. No other major complications occurred.

CONCLUSION

FAW reduced hypothermia and improved thermal comfort. The difference in temperature between groups was modest and less than that observed in previous studies where use of FAW decreased risk of surgical complications. Therefore, it should not be considered clinically significant.

TRIAL REGISTRATION NUMBER

ACTRN12616000013460.

Forced air warming to maintain normoTHERMIa during SEDation in the cardiac catheterization laboratory: protocol for the THERMISED pilot randomized controlled trial

AIM

To determine whether applying forced air warming attenuates the impact of sedation-induced impairment of thermoregulation on body temperature of patients who are sedated during interventional procedures in the cardiac catheterization laboratory.

BACKGROUND

A moderate proportion of sedated patients who undergo procedures in the cardiac catheterization laboratory with only passive warming become hypothermic. Hypothermia in the surgical population is associated with increased risk of adverse cardiac events, infections, thrombotic and haemorrhagic complications and prolonged hospital stay. For this reason, investigation of the clinical benefits of preventing hypothermia in sedated patients using active warming is required.

DESIGN

Randomized controlled trial.

METHODS

A total of 140 participants undergoing elective interventional procedures with sedation in a cardiac catheterization laboratory will be recruited from two hospitals in Australia. Participants will be randomized to receive forced air warming (active warming) or usual care (passive warming with heated cotton blankets) throughout procedures. The primary outcome is hypothermia (defined as temperature less than 36°C) at the conclusion of the procedure. Secondary outcomes are postprocedure temperature, postprocedural shivering, thermal discomfort, major complications, disability-free survival to 30 days postprocedure, cost-effectiveness and feasibility of conducting a larger clinical trial.

DISCUSSION

The results from this study will provide high-level evidence for practice in an area where there is currently no guidance. Findings will be easily translatable into clinical practice because most hospitals already have forced air warming equipment available for use during general anaesthesia.

REGISTRATION NUMBER

ACTRN12616000013460.