The Mölnlycke O.R. blog
Patient warming: Prevention is better than cure
Four reasons patient warming is low priority and how to warm it up
Do you keep your patients sufficiently warm during surgery? If so, you are dramatically improving their chances of avoiding post-operative complications. Nevertheless, while anaesthesiologists are tasked with monitoring patient temperatures during surgery, many patients’ temperatures are not monitored. Given the existing body of evidence as well as concern for general patient comfort, this comes as a surprise.
It is a well-documented fact that the risk for post-operative complications rises when body temperature drops during surgeryi. Because anaesthesia restricts the body’s normal thermoregulatory mechanisms, patients are subject to inadvertent hypothermia, which can lead to serious consequences.
These temperature drops contribute to increases in the frequency of myocardial events (especially myocardial infarctions), increases in blood loss and the need for transfusions, triples the risk for surgical wound infections, prolongs the action of anaesthetic (and other) drugs, doubles post-operative recovery time, prolongs hospitalisation and, not negligibly, but inadvertently, decreases the patient’s well-being as thermal comfort decreases.
The temperature drop does not need to be significant to increase risk – even at temperatures of 36⁰C, we see a rise in riskii.
The key to having control over the temperature is to measure it. Yet only 37 percent of the audience participating in a webinar focused on patient-warming practices in November 2012 stated that they always monitor the patients’ temperatures during surgery. Why? Is patient warming not at the top of our agenda? Do we lack good thermometers? Do we lack good warming devices? Do we not want to know?
I believe the answer is multifaceted:
- Out of sight, out of mind: Patient warming is not foremost in our minds. The surgeon believes it is a purely anaesthetic question. Despite knowing that warming can help cut the risks listed above, patient warming is still treated as a “nice-to-have” rather than a “must-have”.
- Lack of innovation: Knowledge of efficient pre-warming devices has stagnated alongside the lack of updates for temperature-control procedures.
- No ideal solution: Patient-warming solutions are evolving. The devices currently available are not ideal; while many work well in terms of warming patients, different devices suffer from a number of drawbacks, such as bulk, noise, immobility, electrical and logistical issues or simply insufficient numbers available.
- Risk debate: Ongoing debate in the medical community questions whether the most widely recommended and used device disturbs laminar air flow in the O.R., which can create conditions conducive to spreading particles into the wound, thus increasing the risk for infections.
Patient warming: What the experts advise
At the webinar mentioned above, two internationally recognised experts in the field, Professor Dan Sessler and Professor Johan Ræder, shared their views on how this issue – simple to adopt in surgical practice but with potentially perilous consequences if ignored – can be addressed.
- Pre-warming and temperature monitoring
Both Prof Dan Sessler of the Cleveland Clinic in the United States and Prof Johan Ræder of Oslo University Hospital in Norway specifically highlighted the concept of pre-warming as a key tool to avoid inadvertent intraoperative hypothermia. Prof Sessler also advocated monitoring core body temperature in all patients undergoing surgery planned to last more than 30 minutes.
Prof Ræder showed that current clinical practice, without pre-warming, fails to prevent the initial drop in temperature occurring immediately after induction of anaesthesia. This initial post-induction temperature drop occurs regardless of whether we apply forced-air warming or other warming techniques intraoperatively. If, however, pre-warming is applied to the patient, we can prevent this rapid initial drop in core body temperature. Prof Ræder demonstrated evidence from both patients and healthy volunteers.
Dual lenses of prevention and patient comfort
The good news on patient-warming trends is that awareness about the need for patient warming is increasing – and implementing procedures to change a potentially life-threatening situation (and bolster patient comfort) is not out of reach. Patient warming is an easy-to-address problem that has hitherto been treated as something of an afterthought. By adding temperature monitoring to our standard procedures as a critical but simple step and including effective pre-warming devices as a standard part of operating equipment, we can considerably reduce riskiii and preserve the health and comfort of our patients.
Awareness is a warming trend
The wider surgical community is – or should be – warming up to the importance of patient warming. To drive patient-warming practices forward, the community needs not just acknowledgement of patient warming but discussion and education.
Knowing that patient warming reduces post-operative complications is not enough. What more can be done? When are you using patient warming? What warming procedures are recommended in your hospital?
i Sessler DI. Complications of mild hypothermia. Anesthesiology 2001; 95:531-43
ii Sessler DI. Complications of mild hypothermia. Anesthesiology 2001; 95:531-43
iii Kurz A, Sessler DI, Lenhardt R. Perioperative normothermia to reduce the incidence of surgical wound infections and shorten hospitalisation. N Engl J Med 1996; 334: 1209–15.
Melling A, Ali B, Scott E, Leaper D. Effects of preoperative warming on the incidence of wound infection after clean surgery: a randomised controlled trial. The Lancet 2001; 358: 876–80.