Anaesthetic Room Research Articles

An observational study of practice during transfer of patients from anaesthetic room to operating theatre*

We observed practice during transfer of 80 patients from anaesthetic room to operating theatre, to determine the duration of apnoea and the time without monitoring during the transfer process. Median (IQR [range]) time from disconnection of the breathing system in the anaesthetic room to the first breath in theatre was 54 (44-65 [27-196]) s, and from disconnection of the pulse oximetry probe to the first reading in theatre was 90 (74-103 [44-182]) s. In four patients (5%) arterial oxygen saturation fell to 94%, with the greatest desaturation observed 11%. The transfer process may represent a window of opportunity for the occurrence of harm or the first step in a chain of events leading to harm, and is difficult to justify on patient safety grounds.

Basic airway management by junior doctors: assessment and training on human apnoeic subjects in the anaesthetic room*

We assessed the airway management skills of 20 junior doctors on patients in the anaesthetic room, using a self-inflating bag with digital flowmeter to measure exhaled tidal volume. Following induction of anaesthesia the junior doctor attempted to ventilate the patient's lungs with five breaths. If two of these breaths were > 250 ml the assessment was completed. If not, a period of instruction was given followed by a further five-breath assessment. Eight doctors did not need further training; of these, six were senior house officers and seven had been on an Advanced Life Support course. Twelve doctors required instruction and re-assessment. Four were senior house officers and two had been on an Advanced Life Support course. They showed some improvement following the instruction period but never reached the standard of the other eight. Validated courses improve resuscitation skills but hands-on training in the anaesthetic room can also be of benefit in maintaining these skills.

Can Bispectral Index aid laryngeal mask placement in children?

Laryngeal mask airway (LMA) placement requires an adequate depth of anesthesia to prevent patient movement and adverse airway responses. Patient movement, coughing, stridor or laryngospasm at LMA placement may result in transient hypoxia, injury to the patient and prolong time spent in the anesthetic room. The Bispectral Index Score (BIS) is a relatively new tool that has not yet established its place in routine clinical pediatric anesthesia practice. One potential use may be to predict an adequate depth of anesthesia for successful intraoperative interventions such as LMA placement in children. A total of 116 children aged between 1 and 16 years due to have an LMA placed under general anesthesia were enrolled into this prospective, blinded observational study. Complication or success of LMA placement was then analyzed in relation to the BIS value at the time of placement. Other clinical variables were also considered. The difference in BIS values in children with complicated compared with successful LMA placement was small and BIS therefore appears not to be a reliable predictor for either. Inexperience of the anesthetist and a history of recent upper respiratory tract infection (URTI) may be better indicators for complications. Bispectral Index Score appears, from this study, not to be a useful tool to help predict complications of LMA placement or to help reduce airway complications during LMA placement. Other markers may be more useful predictors of adverse airway events.

A grandson's perspective

I warmly hugged and kissed her before she was taken into the anaesthetic room. Feeling a bit drowsy from the premedication, she flashed a smile, a reassuring one that comforted me. She waved goodbye to about 10 relatives who had come to wish her well. They knew she was in good hands—those of a renowned gynaeco-oncologist, who happened to be my dad's best friend from medical school. How strange it must have felt to be operating on his best friend's mum whom he has known for more than 20 years. The …

The reliability of laryngoscope lights

The aim of this study is to compare the brightness of laryngoscope light between instruments, and the variability within the same instrument. A secondary aim is to compare the light from a reusable laryngoscope with a single use design. Testing equipment was constructed which provided a qualitative measure of light output from laryngoscopes. Anaesthetists assessed the minimum acceptable brightness for intubation using the intubating mannikin and a variable brightness laryngoscope. Laryngoscopes in anaesthetic rooms around the hospital were then tested repeatedly, and the results were compared to the anaesthetists' opinions. There was considerable intersubject and intrasubject variation in the reusable design, often failing to satisfy the minimum brightness. The single use blades were found to be brighter and more reliable than reusable blades.

Comparison of buffered and unbuffered local anaesthesia for inguinal hernia repair: a prospective study

Bicarbonate buffered local anaesthetic solutions are known to reduce the pain of infiltration. However, its efficacy in reducing the pain of infiltration in patients undergoing inguinal hernia repair has never been tested. This study aims to test the efficacy of bicarbonate buffered solution in reducing the pain of infiltration and pain for the total surgical procedure in a series of patients undergoing elective inguinal hernia repair. Forty consecutive male patients with unilateral, reducible inguinal hernias were studied prospectively. All patients underwent surgery under local anaesthesia, the first 20 with unbuffered solution and the next 20 using buffered solution. Pain scores were obtained for the infiltration in the anaesthetic room and for the total surgical procedure. In addition, satisfaction scores were obtained at the end of the procedure. The mean pain score for the initial infiltration of unbuffered anaesthetic was 3.00 (range 0-5), and for the buffered anaesthetic it was 1.45 (range 0-4), P=0.02. The mean pain score for the entire procedure for the unbuffered group was 3.05 (range 0-6), and for the buffered group it was 1.45 (range 0-5), P=0.02. The patient satisfaction rate was higher with the buffered solution compared to unbuffered solution (P<0.05). There were no complications reported with either solution. Buffered local anaesthetic solution significantly reduces the perceived pain of inguinal hernia repair, both during the infiltration and during the procedure itself. It is safe to administer and it results in a high rate of patient satisfaction.

The Effect of Combined Fentanyl and Ketamine Administration in the Monitored Anesthetic Care of Ambulatory Strabismus Surgery

Background: Monitored anesthetic care can provide patient safety and optimal surgical conditions. However, propofol and fentanyl decrease the hypoxic ventilatory response and heart rate. Ketamine has less respiratory depression and blocks bradycardia. Furthermore, ketamine can reduce the amount of opioid use but it delays discharge in the outpatient anesthesia. Therefore, this study retrospectively examined the effects of combined fentanyl and ketamine administered during monitored anesthetic care on the use of opioids, cardiorespiratory side effects, and patient discharge. Methods: The anesthetic room, the recovery room and day surgery center records of ambulatory strabismus surgery with monitored anesthetic care was reviewed by anesthesiologists from Oct. 2004 to July 2005. The patients were classified as those receiving either fentanyl (F group: n = 32) or fentanyl and ketamine (FK group: n = 19) with a propofol infusion. The fentanyl dose used, the need for airway support, anticholinergics and naloxone were compared. The stay in the recovery room and the day surgery center was also examined. Results: The FK group used significantly less fentanyl than the F group (P ＜ 0.05). Although airway support was needed, there was less anticholinergics and naloxone used in the FK group, but this difference was not significant. The stay in recovery room and the day surgery center were similar. Conclusions: Co-administered ketamine reduces the amount of fentanyl-needed, but it does not reduce the need for airway support and anticholinergics. In addition, co-administered ketamine does not affect the number of days in the recovery room and day surgery center.

One-dose antibiotic prophylaxis against wound infection after appendicectomy: A randomized trial of clindamycin, cefazolin sodium and a placebo

Two hundred and fifty patients were admitted to a prospective randomized trial of single dosage prophylaxis against wound infection after appendicectomy. There were 12 exclusions, 72 patients received placebo, 81 received 600 mg i.m. clindamycin phosphate and 85 received 1 1 g i.m. cefazolin sodium, the agent being given in the anaesthetic room. Clindamycin produced a significant reduction in the overall rate of wound infection from 33 per cent in the controls to 17 per cent. In cases with a gangrenous or perforated appendix the infection rate in controls was 78 per cent; this was reduced to 44 per cent by a single dose of clindamycin. Cefazolin significantly reduced the number of aerobic organisms isolated from wound infections, but did not significantly reduce the incidence of wound infection. We conclude that anaerobic organisms are more important than faecal aerobic organisms in the pathogenesis of wound infection after appendicectomy.

Autologous predonation, haemodilution and intraoperative blood salvage in elective abdominal aortic aneurysm repair.

The feasibility of predonated autologous blood transfusion and intraoperative blood salvage in elective abdominal aortic aneurysm repair was studied. Twenty consecutive patients were evaluated, of whom five were excluded according to protocol criteria. Patients each donated 1 unit blood 14 and 7 days before operation. A third unit was withdrawn in the anaesthetic room and replaced with Hartmann's solution, producing a haemodiluted state. Intraoperative losses were minimized using the Haemonetics Cell Saver III Plus autotransfusion system. Predonated blood from two patients passed its expiry date owing to repeated operation postponements, leaving 13 patients for study. The mean(s.d.) intraoperative blood loss was 700(300) ml with a mean(s.d.) intraoperative salvage of 420(300) ml. Two patients were transfused intraoperative salvage of 420(300) ml. Two patients were transfused according to clinical need. Thus nine patients safely avoided homologous transfusion. With autologous predonation, haemodilution and intraoperative blood salvage, elective aortic aneurysm repair can be performed safely with minimal need for homologous blood.

A simple model for training in one lung ventilation

The insertion, checking and correct use of double lumen tubes or endobronchial blocking devices for bronchial isolation and one lung ventilation is a key anaesthetic skill. Competent and safe usage requires an appreciation of the mechanical principles underlying these techniques. Unfortunately, opportunities for trainees to gain sufficient experience with these techniques in the clinical setting are often limited both by the availability of appropriate cases and the reduction in trainees' working hours. We have noticed that when confronted with a double lumen endobronchial tube many trainees (and some consultants) do not have a logical system for clinically checking its location and correct function. We have produced a simple and cheap model, assembled from components readily found in most anaesthetic rooms, which can be used to demonstrate and test the mechanical principles underpinning one lung ventilation. The model can be used with both left and right-sided double lumen tubes and single lumen tube and bronchial blocker combinations, although it is not capable of simulating obstruction of the right upper lobe bronchus. Using sections of standard corrugated tubing from an anaesthetic breathing system with 22 mm connectors, a Y-connector from a circle system, two 1 litre anaesthetic reservoir bags, a self-inflating resuscitation bag and a tube clamp, we assembled the device shown in Fig. 8. We found the model valuable in demonstrating the principles of one lung ventilation to anaesthetic trainees, operating department practitioners and nurses working with patients undergoing thoracic surgery. Model trachea showing successful isolation and ventilation of the right ‘lung’ with a right-sided double lumen tube. If the model trachea is intubated with a single lumen tube it can be used for training in fibreoptic bronchoscope-guided bronchial blocker placement. With suitable manipulation of a double lumen tube in relation to the Y-connector, the model can be used to simulate a variety of tube misplacements including over-insertion (tracheal opening within the main bronchus), under-insertion (bronchial opening above the carina) and lateral transposition (such as a right double lumen tube into the left main bronchus) – either individually or in combination. If the ‘carinal’ component of the model is obscured with a drape, it can be used to develop and test anaesthetists' strategies for recognising and managing double lumen tube malposition.

Strength of disposable laryngoscope blades

We have tested several different disposable Miller 1 blades with up to 150 N force applied to the tip to ascertain the flexibility and breaking points. We were concerned to find that all three Miller 1 Vital View blades (Vital Signs Ltd, Littlehampton, UK) that we tested broke, in a similar fashion, at a force of between 111 N and 130 N (Fig. 9). Broken disposable laryngoscope blades. There are no agreed standards for the forces that laryngoscope blades should withstand. We find this an unacceptable position. There has been a lot of interest in the anaesthetic literature regarding the forces that may be exerted during laryngoscopy, and, hence, the forces that these devices should be able to withstand [1, 2]. While we feel frustrated that these blades all broke at what we consider to be relatively low forces, we cannot categorically state that this blade is inadequate. Although some may well argue that one shouldn't exert this degree of force on a paediatric larynx, with no manufacturing standards in place this is merely conjecture. At present there is no independent testing of laryngoscope blades, nor indeed any anaesthetic equipment, as the Medicines and Healthcare products Regulatory Agency decided to withdraw funding for anaesthetic equipment testing in March 2004. We feel that an organisation should be set up to provide standards for anaesthetic equipment in order to prevent our anaesthetic rooms becoming awash with potentially substandard equipment. A. Wilkes was previously funded by the Medicines and Healthcare products Regulatory Agency. Thank you for allowing us to comment. Vital Signs has been manufacturing and distributing single use disposable laryngoscope blades of the Miller and Macintosh style since early 1994. A review of our records show we have shipped more than 1.8 million blades since 2001, and have had only four reported incidences of blade breakage. Specifically, there has been no ‘in-use’ failures of Miller 1 blades reported. Vital Signs, based on studies documented in the literature, established a break force criteria for its disposable blades. This issue is so important that we perform destructive testing on each batch of blades to ensure our specifications are met. We feel that a blade of strength capable of resisting a 100 N force has a large safety factor built in, especially for a Miller 1 or any of the smaller size blades used on individuals in the 3–11 kg weight range. Based on experience of use the Miller 1 blade this appears to be validated. Vital Signs would welcome the opportunity to participate in any efforts to develop standards. We believe most responsible manufacturers are not interested in producing ‘substandard equipment’. We also believe that there are organisations in place to develop standards for anaesthetic equipment such as Technical Committee ISO/TC 121. At this time there may not yet have been an overwhelming need to direct efforts towards developing a standard for ‘disposable’ laryngoscope blades. S. HillManaging Director Vital Signs Ltd. Thank you for the opportunity to reply to the letter from Dr Goodwin and colleagues. The current standard for laryngoscopes for tracheal intubation (EN ISO 7376 : 2003) contains a number of requirements for all types of laryngoscopes; however, it does not address the strength of the blade itself. I understand that the relevant BSI committee is currently preparing a first draft of a standard for single use laryngoscope blades. This will be progressed to either a European or an International standard. Progressing the debate in the European or wider arena will, no doubt, resolve the apparently different views held by manufacturers and the clinical community regarding an appropriate value, and methodology, for testing single use blades. It is disappointing, bearing in mind this letter and earlier Correspondence in Anaesthesia on the same subject, that the Medicines and Healthcare products Regulatory Agency (MHRA) has not received any adverse incident reports arising from breakage of single use laryngoscope blades during use. It is only through the reporting of adverse incidents that MHRA can investigate problems with medical devices and take appropriate action to resolve them. Such information could be used to inform the debate during standards development, to provide the basis for advice to the health service or allow the Agency to take appropriate action with the manufacturer to address an unacceptable level of failure with these devices. Reports can be made directly to the Agency using most communication means (please visit http://www.mhra.gov.uk for details) or, alternatively, they can be made via the local Trust Liaison Officer.

Fentanyl reduces cortisol and blood glucose changes during cataract surgery under retrobulbar anaesthesia 1

Fentanyl reduces cortisol and blood glucose changes during cataract surgery under retrobulbar anaesthesia 1

A response to ‘Routine pre‐oxygenation – a new “minimum standard” of care?’

It is difficult to decide which aspect of Dr Bell's editorial [1] on pre-oxygenation is more irritating, the almost impenetrable syntax or the sentiments expressed. A number of increasingly ludicrous scenarios are discussed, e.g. if a patient refused to co-operate in pre-oxygenation with a trainee, the patient should be counselled, the case should default to a consultant and a critical incident form be submitted. The conclusion seems to be that routine pre-oxygenation offers identifiable safety benefits and could be recommended to the profession. Furthermore ‘It will be interesting to observe…how those practitioners who argue against or ignore any recommendations might be managed’. As I count myself in this latter category and have no wish to be ‘managed’ by those who think like Dr Bell, may I be permitted a few observations? The editorial adduces no evidence in support of ‘identifiable safety benefits’ in otherwise fit patients. Many years ago in my final fellowship, I was asked by Prof. Alistair Spence what were the benefits of giving oxygen in recovery. He countered all my suggestions such as diffusion hypoxia and I have pondered the question for the next 27 years. I have concluded that the only benefit is that the condensation on the clear mask enables the staff to see that the patient is breathing. Adding oxygen only delays recognition of hypoventilation and we had an example of this at our most recent audit meeting. I fear that routine pre-oxygenation of fit patients will also delay recognition of problems, though now that we have CO2 monitoring in all anaesthetic rooms this is less likely than it was in the past. I am all for pre-oxygenating patients that need it such as emergency GA sections, but I think that giving oxygen by a tight fitting face mask for four time constants to a fit day case gynae patient is neither sensible nor supported by evidence.

Intérêt du simulateur d'anesthésie pour l'évaluation des internes d'anesthésie–réanimation

Objective. – The aim of this study was to test simulator validity to evaluate the ability of anaesthesia residents to solve two simulated scenarios.Study design. – Monocentre, prospective, randomized study.Population. – Anaesthesia residents.Methods. – All anaesthesia residents were invited to participate into the study but were free to decline to take part. The authors developed grading forms to evaluate preoperative preparation of anaesthesia room and two simulated scenarios which had been previously validated. All residents were evaluated on the preoperative preparation of anaesthesia room. A randomization was performed to select half of the residents to be tested on one of the simulated scenario. Two experienced anaesthesiologists scored the residents’ performance. At the end of the simulated session, residents rated the realism of the scenarios.Results. – Among 72 training residents in our institution, 48 participated with 24 beginning and 24 advanced residents. Median scores were similar between beginning (first and second year) and advanced residenced (third and fourth year) for the preoperative preparation of anaesthesia room (17 vs 17 for a maximal score of 25) while scores tended to be higher in advanced residents for simulated scenarios (scenario 1 [34 vs 19 for a maximal score of 55; p=0.0009], scenario 2 [17 vs 13 for a maximal score of 45; p=0.58]). However, numerous management errors were observed and some of them did not improve with training. Anaesthesia residents rated the simulator scenarios as realistic.Conclusion. – This study suggests that mannequin-based simulator appears as a reliable and valid tool to test the performance of anaesthesia residents during critical situations.

Consent for practising difficult intubation techniques

The Difficult Airway Society guidelines for management of the unanticipated difficult intubation (Anaesthesia 2004; 59: 675–94) are an extremely useful resource. This is especially true for new anaesthetic senior house officers (SHOs) about to ‘go solo’. Anaesthetists must practise difficult intubation drills and techniques in a controlled environment, and with real patients. But what consent should be sought? Some techniques may be integral to the anaesthetic, and do not therefore need specific consent (for example intubation in the lateral position, use of the Eschmann tracheal tube introducer, or even ‘practising’ the use of the intubating LMA when a tracheal tube is required). But what about techniques used purely for teaching purposes such as simulated grade 3 and 4 laryngoscopy, or deliberate oesophageal intubation in order to practise auscultation and the use of oesophageal detectors? Anaesthetic room teaching is often opportunistic. To obtain consent from all patients pre-operatively for potential teaching of these techniques would be extremely challenging, as well as time consuming and stressful for patients. Ultimately, it could result in more anaesthetic time on the ward, with more delays to lists and less practice in the lifesaving skills of difficult airway management. Ignoring the issue of consent, could however, be construed as paternalistic. The scandal over organ retention indicates how important this issue is to the public. Yet the problems surrounding the original Human Tissue Bill – 1 min of staff time spent gaining consent for every sample covered by the Bill, adds up to the total work of several medium sized DGHs — highlights the consequences of seeking to address it. Is there a consensus on acceptable practice?

The use of anesthetic rooms for pediatric anesthesia requires justification

The use of anesthetic rooms for pediatric anesthesia requires justification

Use of anaesthetic rooms in obstetric anaesthesia; a postal survey of obstetric anaesthetists and departments in the United Kingdom

Use of anaesthetic rooms has been much discussed in the UK in recent years, but attitudes and practices of obstetric anaesthetists regarding their use for caesarean section have never been sought. A postal survey was conducted to discover the extent of use of anaesthetic rooms versus operating theatre for induction of anaesthesia and reasons for using or not using them. Questionnaires regarding individual practices were sent to 400 randomly selected members of the Obstetric Anaesthetists' Association ( approximately 25% of UK membership). Questionnaires regarding departmental policies were sent to 100 "clinicians responsible for surveys" (approximately 38% of departments providing obstetric anaesthesia in the UK). For elective caesarean section, 70% of individual clinicians never used an anaesthetic room, 9% rarely, 5% usually, 9% for all regional anaesthetics and 6% always. For emergency caesarean section the corresponding figures were 83%, 5%, 5%, 3% and 2% respectively. Use of the anaesthetic room was independent of the seniority of anaesthetists. In 68% of departments it was standard practice or policy to induce all anaesthetics for caesarean section in the operating room. Conversely, only 1% of departments had a policy to induce all anaesthetics in the anaesthetic room. Patient safety was the usual reason given for anaesthetising in the operating room. The majority of obstetric anaesthetists have abandoned the use of anaesthetic induction rooms, the main reason being patient safety. For the same reason, two-thirds of departments providing obstetric anaesthesia consider induction of anaesthesia in the operating room their standard practice.

Hepatitis

Blood-borne viral infections have implications for anaesthesia and intensive care because of their potential for transmission and as disease entities. An increasing number of hepatotropic viruses have been identified and may be acquired from faecal contamination (hepatitis A and E) or parenterally via body fluids (hepatitis B, C, D and G). These hepatotropic viruses preferentially cause hepatitis and exhibit this preference to a greater (hepatitis A and B) or lesser (hepatitis G) degree. In ICU and theatres, standard precautions should always be adopted. Factors that contribute to transmission are: sharps containers with straight drop systems that allow ‘overstuffing’ trying to recover needles after use; lack of gloves or using gloves on more than one patient; inadequately sterilized devices; re-using single-use devices; multi-dosing from a single drug bottle or ampoule. One study demonstrated that 33% of theatre surfaces investigated were contaminated with blood after surgery, including blood pressure machines, oximeters, ventilators and laryngoscopes (blade and handle). For this reason, it is sensible to schedule patients with hepatitis last on the list and thoroughly clean the theatre and anaesthetic room afterwards. Unvaccinated individuals exposed to HBV, or those whose anti-HBsAb levels are less than 10 IU/litre should receive anti-HBs immunoglobulins and start a course of vaccination within 7 days. Post-exposure seroconversion due to HBV or HCV warrants hepatological referral for treatment, which is described in the article.

Factors influencing time of intubation with a lightwand device in patients without known airway abnormality

Study objective To evaluate the correlation between accepted screening tests for difficult tracheal intubation and ease of intubation with a lightwand blind technique. Design Prospective study. Setting Anesthetic rooms of a university hospital. Patients 122 female, ASA physical status I, II, and III patients requiring tracheal intubation for elective surgery. Interventions After receiving a standardized anesthetic induction, patients first underwent direct laryngoscopy to determine Cormack laryngoscopy grade, then tracheal intubation was performed using a transillumination method. Measurements and main results Patient demographics, Mallampati class (MC), mouth opening (MO; cm), and thyromental distance (TMD; cm) were all measured and the values recorded. Body mass index (BMI; kg/m 2) was calculated for each patient. Laryngoscopy grades obtained by laryngoscopy were also recorded. Times to intubation were measured by a chronometer and failures were recorded. Patients were then allocated to groups according to the measured parameters: BMI ≥ 30 kg/m 2, BMI < 30 kg/m 2; TMD ≥ 6 cm, TMD < 6 cm; MO ≥ 3, MO < 3; MC I, MC II, MC III, MC IV, and Laryngoscopy Grade (LG) 1, LG 2, LG 3, LG 4. Intubation times at the first attempt were compared within the groups for each variable. The total results of 119 patients were studied; overall success was 99%, and mean time to intubation at the first attempt was 9.2 ± 4.9 seconds. Although time to intubation was prolonged with increasing Mallampati and laryngoscopy scores, and in the TMD < 6 cm and BMI ≥ 30 kg/m 2 groups, only the MC III and BMI ≥ 30 kg/m 2 groups represented a statistically significant difference of prolongation. Mean time to intubation in the MC III and BMI ≥ 30 kg/m 2 groups were 13.2 ± 5.4 ( p = 0.011) and 14.8 ± 1.7 ( p ≤ 0.001), respectively. Conclusion Mallampati class III airway significantly increases time to intubation when the transillumination technique is used. BMI ≥ 30 kg/m 2 is another factor that interferes with the ease and success of intubation with this technique.

HIGHER OPERATION ROOM TEMPERATURE IS MORE EFFECTIVE IN MAINTAINING NORMAL CORE TEMPERATURE IN HEALTHY DONORS UNDERGOING LIVING DONOR HEPATECTOMY

A151 Aims: Hypothermia during surgery should be prevented. Low flow anesthesia and higher ambient operation room temperature have been documented to be effective in preserving core temperature of the patients during operation. We evaluate the efficacy of combining both methods in maintaining core temperature in healthy donors undergoing living donor hepatectomy Methods: Healthy candidates undergoing living donor hepatectomy were divided into two groups according to the setting of operating room temperature (ORT). ORT of 19-21 ° C was set in GI while ORT of GII was 24° C. General anesthesia was given using low flow isoflurane for both groups. Nasopharyngeal temperature (NT) were monitored and compared hourly between groups by using Mann Whitney test, p< 0.05 was regarded as significant. Results: 62 healthy donors, 31 for each group were studied. Figure 1 shows that the NT of GII was significantly higher from the beginning to the end of the operation.FigureConclusions: Our retrospective study showed that the strategy of using higher than usual ambient ORT in addition to low flow anesthesia is more effective for the maintenance of normothermia in patients undergoing abdominal surgery of long hours such as living donor hepatectomy.