C3CONSEQUENCES OF INADVERTENT PERIOPERATIVE HYPOTHERMIA - RCT STUDIES

StudyParticipantsInterventions
Bennett 1994
Trial held in UK
Inclusion: Patients undergoing hip arthroplasty;
Exclusion: patients who were grossly obese or malnourished or who had endocrine abnormalities or pyrexia
Age (range):71(range 59–88): 74 (range 54–84); 73 (range 63–89): gender (m/f): 30:15; Duration of surgery: 2.0 hours (SD 0.3): 2.5 hours (SD 0.6): 2.3 hours (SD 0.3);
Comorbidities: not stated; ambient temperature: 19–21°C; IV at ambient temperature at rate of 6ml/kg/h. Blood warmed to 37°C before infusion. Relative humidity maintained at 40–50%; ambient temperature (recovery)-23–25°C
  1. Metallized plastic garment (Thermolite, techstyles (thermal insulation; duration: after induction until end of surgery; n=15
  2. usual care; duration: not stated; n=15
  3. Convective warm air blanket (Bair Hugger); 43°C; n=15
Casati 1999
Trial held in Italy
Inclusion: patients undergoing total hip asthroplasty
Exclusion: patients with severe CV and respiratory disease, obese, thyroid disease, dysautonomi or Raynaud's syndrome
Age (range):68 years (SD 11): 66 (SD 7); gender (m/f): not stated; Duration of surgery: 100 min (SD 37): 105 (SD 18);
Comorbidities: not stated; 3 ml of Ringer's solution infused every 1ml of blood loss; all patients were in supine position; autologus blood warmed to 37°C before infusion
  1. Forced air warming (Bair Hugger) + IV Ringer's solution (37°C) (active warming device); duration: after loss of sensation at t10 until end of surgery; not stated; n=25
  2. Reflective blankets (thermal insulation); duration: after loss of sensation at t10 until end of surgery; n=25
Fleisher 1998
Trial held in USA
Inclusion: patients classified as ASA physical status I, II, or III, aged 18 to 85 yr scheduled for gynaecologic, plastic orthopaedic, or general surgery and for post surgical admission to one PACU location, included elective surgery scheduled for at least 2h and the use of general endotracheal anaesthesia
Exclusion: patients with coronary artery disease, combined general and regional anaesthesia, perioperative fever (>38°C oral), minor peripheral procedures, factors that precluded the use of a lower body FAW blanket (i.e. use of leg stirrups or lower extremity surgery)
Age (range): 45 years (SD3) (for 95/99 patients included) (18 to 85); gender (m/f): 18:77 (of 95 patients included) Comorbidities: not stated; room temperature: 21°C; core temperatures maintained between 34.5°C and 38°C in all patients and if increased to >38°C anaesthesiology and surgical teams were notified; extubation based on criteria of adequate spontaneous ventilation, return of airway reflexes, sustained head lift for 5s as determined by anaesthesiologist; times from completion of surgical dressing until extubation measured in both groups and used as a measure of post surgical emergence time from anaesthesia
  1. Forced-air warming cover (Mallinckrodt Medical) + prewarmed crystalloid, passive airway humidification and a lower extremity warming blanket completely covered by a cotton blanket and surgical drapes; units turned on to high and high flow settings after drapes placed; duration: not stated; duration: discontinued once temperature increased to >34.5°C; n=48
  2. Routine thermal care + prewarmed crystalloid, passive airway humidification and a lower extremity warming blanket completely covered by a cotton blanket and surgical drapes; blankets connected to warming unit which was turned on but not programmed to deliver air; duration: not stated; if routine thermal care temperature decreased to <34.5 FAW initiated to prevent decrease in core temperature; n=47
Frank 1995
Trial held in USA
Inclusion: patients age > 60 years; scheduled for lower vascular, abdominal or thoracic procedures; presence of 2 or more risk factors for CAD
Exclusion: patients with ECG abnormalities, preoperative temperature < 36°C or > 38°C; history of Raynaud’s or thyroid disease
Age (range):71 (SEM 1); gender (m/f): 85:82
Comorbidities: not stated; room temperature: 21°C; endotracheal tube removed at end of surgery unless standard extubation criteria not met; in PACU for the control group: warmed blankets placed over patients at nurse’s discretion; FAW group: intervention continued for 2 hr and similar to control group
  1. Forced-air warming cover (Mallinckrodt Medical) + IV fluid and blood warmed (model bw-5) + HME (thermovent) (active patients + active fl); duration: not stated; set at height and adjusted to maintain core temperature at 37°C; n=37
  2. Warmed IV fluids (usual care+ active fl); duration: not stated; n=37
Frank 1997
Trial held in USA
Inclusion: patients age > 60 years; scheduled for peripheral vascular, abdominal or thoracic procedures; scheduled for postoperative admission to the ICU; documented or at high risk of CAD (age criterion to preselect patients at risk for both perioperative CV complications and inadvertent hypothermia)
Exclusion: patients with ecg abnormalities, preoperative temperature < 36°C or > 38°C; patients with Raynaud’s or thyroid disease
Age (range):71; gender (m/f): 85:82
Comorbidities: not stated; room temperature: 21°C; endotracheal tube removed at end of surgery unless standard extubation criteria not met; surgery duration 3.4 and 3.6h (SEM 1.1)
  1. Forced-air warming cover (Mallinckrodt Medical) + IV fluid and blood warmed (model bw-5) + HME (thermovent) (active patients + active fl); duration: not stated; set to maintain core temperature at 37°C; n=142
  2. 1 layer of paper of surgical field+ IV fluid and blood warmed + heat moisture exchanger (usual care+ active fl); duration: not stated; n=158
Hofer 2005
Trial held in Switzerland
Inclusion: Patients undergoing elective multiple off-pump coronary artery bypass grafting, with preserved left ventricular function (ejection fraction >40%), absence of platelet glycoprotein inhibitor therapy, preoperative hematocrit 30% or higher, preoperative normothermia and no pre-existing coagulation disorders.
Age: 66.3 years (SD 10.9): 64.4 (SD 10.7): 65.6 (SD 11.8); gender (m/f): 72:18; All patients received warmed transfusions (40°C); Duration of surgery: 232 min (SD 65): 248 (SD 46): 249 (SD 68)
  1. Forced air warming (Warm Touch; Mallinckrodt Inc); (active warming device); duration:after induction of anaesthesia; 42oC; n=29
  2. Electric blanket (Thermamed SmartCare OP; (active warming device) system); duration:after induction of anaesthesia;42oC; n=30
  3. Water garment (Allon 2001 system; MTRE); (active warming device); duration:after induction of anaesthesia; 36.7oC; n=29
Johansson 1999
Trial held in Sweden
Inclusion: elective total unilateral primary hip arthroplasty, no pathologic fracture, no anamnestic evidence of coagulopathy, and prothrombin and activated partial thrombin time within normal limits. Age (range):69 (SD 7): 67 (SD 7); gender (m/f): 21:29; comorbidities: not stated; Duration of surgery: 102 min (SD 20): 100 min (SD 23); Premedication: diazepam, 5 mg by mouth used for sedation; ephedrine (5(7.6) v 4.3(6) mg); midazolam IV (2(1.8) v 1.3(1.5)mg); NSAIDs/aspirin discontinued 1 wk before operation in 8 patients in each group; fl and blood warmed; or temperature: 20.9°C
  1. Bair hugger (Augustine Medical) + pre-warmed gel-filled mattress + warmed fluids (active patients + active pt); duration: not stated; n=25
  2. Usual care + pre-warmed gel-filled mattress + warmed fluids (active warming device); duration: not stated; n=25
Kurz 1996
Trial held in USA
Inclusion: colorectal resection for cancer or IBD; surgery duration 3.1 h (SD 1.0)
Exclusion: patients scheduled for minor colon surgery, use of corticosteroids or other immunosuppressive drugs including cancer chemo 4 weeks before surgery; recent history of fever, infection or both; serious malnutrition or bowel obstruction
Age (range):60 years (18–80); gender (m/f): 108:92 comorbidities: not stated; inflammatory bowel disease; mechanical bowel prep night before surgery
  1. Forced air cover (Augustine Medical) + warmed IV fluids (fluid warmer)-activated (active warming device); duration: not stated; 40°C; n=104
  2. Forced air cover (Augustine Medical) + warmed IV fluids (fluid warmer)- not activated (active + passive); duration: not stated; ‘ambient temperature’; n=96
Lenhardt 1997
Trial held in USA
Inclusion: patients aged 18–80 years undergoing abdominal surgery (colon resection with or without abdominal peritoneal pull stable, systemic disease); ASA I–III; Exclusion: patients scheduled for minor abdominal surgery; Duration of surgery: 3.4 hours (SD 1.2): 3.2 (SD 1.1)
Age (range):56 (SD 17): 55 (SD 16); gender (m/f): 74:76 Comorbidities: not stated; 100 of the patients participated in kurz 1996
  1. Extra warming (active warming device); duration: not stated; core temperature maintained near 36.5°C; n=74
  2. usual care; duration: not stated; n=76
Mason 1998
Trial held in USA
Inclusion: Roux-en-y gastric bypass surgery for morbid obesity
Exclusion criteria not stated
Age (range): 38.5 (SD 6.1): 40.7 (SD9.6); (17–59 years); gender (m/f): 9:55; Duration of surgery: 156.1 min (SD 27.4): 156.9 (SD 31.6)comorbidities: not stated; or temperature: 20.9°C; PACU temperature: 24.75°C
*significantly different between the groups length of incisim (cm). Length of incision longer in warmed blanket group
  1. Forced air warming [Bair Hugger (Model 500 Augustine Medical)] (active warming device); duration: not stated; ‘medium’= 38°C (SD 3); n=32
  2. Warmed cotton blankets (active warming device); duration: not stated; n=32
Scott 2001
Trial held in UK
Inclusion: Patients over 40 years undergoing orthopaedic, colorectal, gastrointestinal, urological and vascular surgery; ASA I–IV; undergoing major surgery with an expected hospital stay of 5 days; no existing sacral pressure ulcers and provided informed consent
Exclusion: patients undergoing procedures in which intraoperative warming standard practice; lateral or prone position
Age (range):68.4 years (SD 9.1): 68.2 (SD 9.2) (41–89); gender (m/f): 149:175; Duration of surgery: 111 min (SD 47.4): 115.5 (SD 46.8);
comorbidities: not stated; 27 protocol violations; 17 patients allocated to warming treated as usual care and 10 patients assigned to usual care given warming because of clinical need; some control patients may have received warmed IV fluids
  1. Forced air warming + warmed IV fluids (active warming device); duration: not stated; n=161
  2. Usual care + warmed IV infusions, as determined by clinical need.usual care; duration: not stated; n=163
Smith 1998
Trial held in USA
Funding: not stated
Inclusion: type of surgery: laparasocpy (74%), hysterectomy (21%), cone biopsy (14%); Exclusion: head injury, otitis, and preoperative temperature greater or equal to 38°C or less than or equal to 35.5°C and patients taking calcium channel blockers.
Age: 33 (SEM 2):
Surgery type: elective; surgical speciality: gynaecology;
Duration of surgery: 67 min (SEM 16): 75 (SEM 15)
Anaesthesia type: general; anaesthesia duration more than 1h; premed: not stated;
ASA grade: I–III; age (range): 33; gender (m/f): 0:38; BMI: not stated;
comorbidities: not stated; gas flow: 2l/min;room temp:@ 21°C;
  1. Hotline (Llevel 1) (active fl); duration: until end of surgery; then room temperature fluids; set point: 42°C (delivers at 38–39 °C); n=18
  2. Room temperature fluids usual care; duration: not stated; 21°C; n=20
Smith 2007
Trial held in USA
Funding: metro-Health medical center, Smiths medical asd inc (formerly sims)
Inclusion: gynaecological, orthopaedic, urological, general surgery scheduled >30mins

Exclusion: <18/>85 years; abnormal bleeding; malignant Hyperthermia (or fh); pre-operationtemperature >38/<35 c, chemo/major Irvine, last 3 mo; immuno-suppressed/steroids last 2 wk; coagglutinins/vasospasm; pregnancy

Perioperative phase: pre and intra; surgery type: elective; surgical speciality: mixed surgery
Duration: 30 to 60 min; anaesthesia type: general; anaesthesia duration more than 1h; premed: midazolam; some patients ASA grade: mixed
Age (range): 40 and/−13 years; gender (m/f): 98: 238; BMI: not stated; comorbidities: not stated; 6 patients in each group had diabetes; 67 and 72 were smokers; ambient temperature 21°C; temperature measures; sublingually pre-operation and postoperatively and oesophageal or nasopharyngeal intra-operatively
  1. Snuggle warm convective warming system, sims, Irvine, ca and warmed IV fluids (active warming device); duration: aim for 30 mins; actually 42 and/−38 min pre- and intra-op; 40 and/−1 degree c; intervention body area covered: 40%; proportion covered; n=156
  2. Convective air warming and/or warmed IV fluids at discretion of anaesthetist usual care; duration: not stated; control body area covered:; proportion covered: not stated; n=180
Widman 2002
Trial held in Sweden RCT
Inclusion and exclusion criteria: age: 67 (SD 7) years; gender (m/f): 23: 23; comorbidities: not stated; ambient temperature 21°C. Hip arthroplasty; duration of surgery 78 (SD 15) and 80 (SD 20) min
  1. Amino acid (amino acid); duration: 1 he before surgery and during; n=22
  2. Acetated ringer’s solution (placebo); duration: not stated; n=24
Wills 2001
Trial held in Australia
Funding: Cook Medical loaned equipment
Inclusion criteria: laparoscopic fundoplication; Exclusion:if patient allergic to morphine, large hiatal hernia (>6cm), previous oesophageal surgery, requiring concomitant procedure such as cholecystectomy, postoperative intubation, conversion to an open procedure
Surgery type: elective; surgical speciality: Surgery duration: 30 to 60 min
Anaesthesia type: general; anaesthesia duration not stated; premed: midazolam (0.1mg/kg) i.m;
ASA grade: not stated; age (range): 47.5 (21–71): 52.2 (28–74); gender (m/f): 22:18; BMI: 28 kg/m2
comorbidities: not stated;
Warming device placed over the upper torso and head (Bair Hugger); OR temp: 20 to 22oC.
  1. Heated CO2 (lins-2000, Cook Australia) (active pt + active gas); duration: not stated; 22 to 30.5oc(at 1 to 6 l/min); n= 19
  2. Standard CO2 (active pt + usual care gas); duration: not stated; amount; n=21
Winkler 2000
Trial held in Austria
Inclusion: patients scheduled to undergo primary, unilateral, cement-free total hip arthroplasty. None performed for treatment of tumour
Exclusion: preoperative coagulation tests abnormal, aspirin products consumed within a week of surgery, history of bleeding disorders, dvt, pulmonary embolism
Age (range):64.5 (40–80)years; gender (m/f): 65:85 comorbidities: not stated; concurrent treatments, ward temperature, irrigation fluid, IV fluid, humidity, air flow
  1. Forced air covers attached to individual forced air heater (Bair Hugger, Augustine Medical) (active warming device); duration: not stated; temperature adjusted to maintain core temperature at 36.5°C; n=75
  2. Forced air covers attached to individual forced air heater(Bair Hugger, Augustine Medical) (active warming device); duration: not stated; temperature adjusted to maintain core temperature at 36.0°C; n=75
Zhao 2005
Trial held in China
Funding: not stated
Inclusion & exclusion criteria: inc: Patients scheduled for abdominal surgery lasting at least 2 hours; Ex: pts w/coagulation disorder, severe malnutirition (total plasma albumin <3.0 g/l, white blood count <2.5x109/l), recent history of fever or infection, history of endocrine disease; Patients with recent use of immunosuppresants perioperative phase: intrafluids
Surgery type: not stated; surgical speciality: not stated; surgery duration: not stated
Anaesthesia type: general; anaesthesia duration more than 1h; Premedication; no; ASA grade: I–II; age (range):52(SD 13): 44 (SD 15); 18–70; gender (m/f): 23:17; BMI: not stated
comorbidities: not stated;
Concurrent treatments, ward temperature, irrigation fluid, IV fluid,humidity, air flow
*FAW: lowered to medium 41–42 if core temperature went above 37.8oC.
Colloid infusion: 800 ml (SD 474) v 945 (SD 394);
  1. Forced air warming + actively warmed intravenous solutions including blood (39°C (active pt + active fl); duration: not stated; FAW: high (42–43°C)*fluid: warmflo:39°C; n=20
  2. Single layer of cotton sheet usual care; duration: not stated; amount; n=20

From: APPENDIX C, CHARACTERISTICS OF INCLUDED STUDIES

Cover of The Management of Inadvertent Perioperative Hypothermia in Adults
The Management of Inadvertent Perioperative Hypothermia in Adults [Internet].
NICE Clinical Guidelines, No. 65.
National Collaborating Centre for Nursing and Supportive Care (UK).
Copyright © 2008, National Collaborating Centre for Nursing and Supportive Care.

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