Monitoring temperature in children undergoing anaesthesia: a comparison of methods

 TFE Drake-Brockman, M Hegarty, NA Chambers, BS von Ungern-Sternberg

 Anaesthesia and Intensive care

Volume 42, Issue 3 May 2014,315-320

Children undergoing anaesthesia are prone to hypothermia. Perioperative monitoring of patient temperature is, therefore, standard practice. Postoperative temperature is regarded as a key anaesthetic performance indicator in Australian hospitals. Many different methods and sites of temperature measurement are used perioperatively. It is unclear to what degree these methods might be interchangeable. The aim of this study was to determine the relationships between temperatures measured at different sites in anaesthetised children. Two hundred children, 0 to 17 years, undergoing general anaesthesia for elective non-cardiac surgery, were prospectively recruited. Temperature measurements were taken in the operating theatre concurrently at the nasopharynx, tympanic membranes, temporal artery, axilla and skin (chest). Patient age and weight were documented. Temperatures varied according to site of measurement. 

The mean difference from nasopharyngeal temperature to temperatures at left and right tympanic, temporal, axillary and cutaneous sites were +0.24°C, +0.24°C, +0.35°C, -0.38°C and -1.70°C, respectively.

 Levels of agreement to nasopharyngeal temperature were similar at tympanic, temporal and axillary sites. Tympanic and temporal temperatures were superior to axillary temperatures for detection of mild hypothermia (<36°C). Skin temperature showed a large variation from nasopharyngeal measurements. Our findings indicate that measured temperatures vary between sites. Understanding these variations is important for interpreting temperature readings.  

Impact of sevoflurane anesthesia on brain oxygenation in children younger than 2 years

Ossam Rhondali et al.

Pediatric Anesthesia

Volume 24, Issue 7, pages 734–740, July 2014

Children younger than 2 years, ASA I or II, scheduled for abdominal or orthopedic surgery were included.

 Induction of anesthesia was started by sevoflurane 6% and maintained with an expired fraction of sevoflurane 3%. Mechanical ventilation was adjusted to maintain an endtidal CO₂ around 39 mmHg. Brain oxygenation was assessed measuring regional cerebral saturation of oxygen (rSO₂c), measured by NIRS while awake and 15 min after induction, under anesthesia. Mean arterial pressure (MAP) variation was recorded.

Despite a significant decrease of MAP, 1 MAC of sevoflurane induced a significant increase in regional brain oxygenation. But subgroup analysis showed that MAP decrease had a greater impact on brain oxygenation, in children younger than 6 months. 

According to their results, MAP value during anesthesia should not go under 33 mmHg in children ≤6 months and 43 mmHg in children >6 months, as further changes in MAP, PaCO₂ or hemoglobin during anesthesia may be poorly tolerated by the brain.

Asleep Versus Awake: Does It Matter?: Pediatric Regional Block Complications by Patient State: A Report From the Pediatric Regional Anesthesia Network.

Reg Anesth Pain Med. 2014 Jun 10.

Taenzer AH, Walker BJ, Bosenberg AT, Martin L, Suresh S, Polaner DM, Wolf C, Krane EJ

The investigators analized  more than 50,000 pediatric regional anesthesia blocks from an observational prospective database, and determined  the rate of adverse events in relation to the patient's state at the time of block placement. Primary outcomes considered were postoperative neurologic symptoms (PONSs) and local anesthetic systemic  toxicity (LAST). Secondary outcome was extended hospital stay due to a block complication.

Postoperative neurological symptoms occurred at a rate of 0.93/1000 (confidence interval [CI], 0.7-1.2) under GA and 6.82/1000 (CI, 4.2-10.5) in sedated and awake patients.

The only occurrence of PONSs lasting longer than 6 months (PONSs-L) was a small sensory deficit in a sedated patient (0.019/1000 [CI, 0-0.1] for all, 0.48/1000 [CI, 0.1-2.7] for sedated patients).

 There were no cases of paralysis.

There were 5 cases of LAST or 0.09/1000 (CI, 0.03-0.21). The incidence of LAST in patients under GA (both with and without NMB) was 0.08/1000 (CI, 0.02-0.2) and 0.34/1000 (CI, 0-1.9) in awake/sedated patients.

Extended hospital stays were described 18 times (0.33/1000 [CI, 0.2-0.53]). The rate for patients under GA without NMB was 0.29/1000 (CI, 0.13-0.48); GA with NMB, 0.29/1000 (CI, 0.06-0.84); sedated, 1.47/1000 (CI, 0.3-4.3); and awake, 1.15/1000 (CI, 0.02-6.4).

They conclude that  the placement of regional anesthetic blocks in pediatric patients under GA is as safe as placement in sedated and awake children.

Effect of General Anesthesia in Infancy on Long-Term Recognition Memory in Humans and Rats.

Stratmann G et al

Neuropsychopharmacology. 2014 Jun 9.

The authors compared twenty eight children ages 6-11 who had undergone a procedure requiring general anesthesia before age 1 to twenty eight age- and gender-matched children who had not undergone anesthesia.

 Recollection and familiarity were assessed in an object recognition memory test using receiver operator characteristic analysis. In addition, IQ and Child Behavior Checklist scores were assessed.

 In parallel, thirty three 7-day old rats were randomized to receive anesthesia or sham anesthesia. Over ten months, recollection and familiarity were assessed using an odor recognition test.

They found that anesthetized children had significantly lower recollection scores and were impaired at recollecting associative information compared to controls. Familiarity, IQ, and Child Behavior Checklist scores were not different between groups.

In rats, anesthetized subjects had significantly lower recollection scores than controls while familiarity was unaffected. Rats that had undergone tissue injury during anesthesia had similar recollection indices as rats that had been anesthetized without tissue injury.

These findings suggest that general anesthesia in infancy impairs recollection later in life in humans and rats. In rats, this effect is independent of underlying disease or tissue injury.

Dose requirements or remifentanil for intubation in non paralized chinese children

Hua-Cheng Liu  et al

Pediatric Anesthesia

Volume 24, Issue 5, pages 505–509, May 2014

When used in combination with 2.5 mg·kg⁻¹ of intravenous propofol, ED50 and ED95 of remifentanil for adequate intubation in nonparalyzed children were lower than previously reported, at 2.30 and 2.75 μg·kg⁻¹, respectively.

Blood component transfusion increases the risk of death in children with traumatic brain injury

Acker, Shannon N. MD; Partrick, David A. MD; Ross, James T. BS; Nadlonek, Nicole A. MD; Bronsert, Michael PhD; Bensard, Denis D. MDJournal of Trauma and 

Acute Care Surgery:

April 2014 - Volume 76 - Issue 4 - p 1082-1088

Pediatric patients sustaining TBI who receive blood transfusion and do not require operative intervention have worse outcomes compared with patients who do not receive transfusion. This includes an increased risk of death. These data suggest that a transfusion trigger of hemoglobin level at 8.0 g/dL in injured children with TBI may be beneficial.