Nigerian Journal of Clinical Practice

: 2019  |  Volume : 22  |  Issue : 2  |  Page : 181--185

Clinical evaluation of postoperative fever in patients that had oral and maxillofacial surgery in university of Nigeria Teaching Hospital, Ituku–Ozalla, Enugu, Nigeria

UC Okechi1, CC Uguru1, A Obiechina2,  
1 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, College of Medicine, University of Nigeria, Ituku–Ozalla, Enugu, Nigeria
2 Department of Oral and Maxillofacial Surgery, University of Port Harcourt, Port Harcourt, River State, Nigeria

Correspondence Address:
Dr. U C Okechi
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, College of Medicine, University of Nigeria, Ituku- Ozalla, Enugu


Background: Postoperative fever (POF) is often encountered after major oral and maxillofacial surgical procedures. This could become an unwanted complication, requiring detailed clinical evaluation and investigations to determine the cause. Aim: The aim is to determine the major causes of POF in patients that had oral and maxillofacial surgery under general anesthesia at the University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu. Materials and Methods: The selected patients were admitted and prepared for surgery. Eight hourly axillary temperature readings were taken from the day of admission till discharge. Necessary samples were collected for laboratory analysis from patients that developed fever after their surgery. Results: The patients consisted of 70 males (64.8%) and 38 females (35.2%) giving a ratio of 1.8:1. The mean age of the patients was 27.15 years (SD 13.1). Of the 108 patients studied, 23 (21.7%) developed fever after their surgery. In majority of the patients, the POF lasted within the first 4 days of surgery. There was a significant relationship between duration of surgery and POF. Conclusion: This study suggests that most cases of POF are of early onset and of short duration. The longer the surgery time, the more likely POF will occur.

How to cite this article:
Okechi U C, Uguru C C, Obiechina A. Clinical evaluation of postoperative fever in patients that had oral and maxillofacial surgery in university of Nigeria Teaching Hospital, Ituku–Ozalla, Enugu, Nigeria.Niger J Clin Pract 2019;22:181-185

How to cite this URL:
Okechi U C, Uguru C C, Obiechina A. Clinical evaluation of postoperative fever in patients that had oral and maxillofacial surgery in university of Nigeria Teaching Hospital, Ituku–Ozalla, Enugu, Nigeria. Niger J Clin Pract [serial online] 2019 [cited 2019 May 26 ];22:181-185
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Full Text


Body temperature measurement remains one of the oldest and most reliable ways of determining the beginning of a disease process in an otherwise healthy person.[1] It is an important indicator of how well the homeostasis is maintained in an individual.[2] Surgical procedures often times disturb this normal physiological process and one such manifestation is for the body temperature to rise. Causes of postoperative fever (POF) have been found to include trauma, infection, deep vein thrombosis, drugs, blood transfusion, and malaria parasites among others.[3]

Fever generally occurs as a result of cytokines released in response to a number of stimuli; these cytokines (pyrogenic cytokines) include interleukin (IL)-1 and 6, tumor necrosis factor alpha, and interferon gamma and are produced by many different tissues and cells of the body.[4],[5],[6]

A number of cases of POF arising specifically from oral and maxillofacial surgery (OMFS) procedures have been documented.[7] Cases of mediastinitis and subcutaneous emphysema which presents with fever have been linked to compressed air powered hand pieces.[8] Fever in the postoperative period can be challenging to the surgeon; its management may require detailed history and clinical examination with occasionally specialized investigation to determine the cause.[4],[9] Surgical intervention and special medications will further prolong patients' hospital stay ultimately leading to increased cost of management.[6],[10],[11]

This study aims to determine the causes and presentation of POF in patients who had OMFS under general anesthesia (GA) from October 2014 to September 2015 in our center.

 Materials and Methods

Study setting

This study was carried out at the University of Nigeria Teaching Hospital (UNTH), Ituku–Ozalla, which is about 21 km from the capital city of Enugu. The hospital is the only referral center for OMFS practice in the southeast Nigeria; hence, it covers all the southeastern states and part of south–south and middle belt states of Nigeria. It runs in-patient, out-patient, and emergency services in many specialized areas of medicine including OMFS. Enugu has a population of over 3 million people.[12]

Study design

This was a 1-year prospective observational study of patients who had OMFS procedures performed under GA in UNTH. Patients were recruited from the OMFS clinic, and accident and emergency unit of the hospital.

Inclusion criteria

Patients that meet the inclusion criteria were those whose body temperatures were not up to 38°C in the preoperative days booked for surgery and admitted into the ward.

Preparation and surgical operation

Patients selected for the study were admitted into the ward for preparation 2 days before the surgery. The first day of admission was defined as day minus two (−2) and the day of the surgery as day zero (0). Patients had routine preoperative assessment to exclude any undiagnosed comorbid condition or to ensure that those with comorbid conditions are stable. Study variables such as sociodemographic characteristics, type of surgery, preoperative body temperature readings, and diagnosis were recorded. Time of onset of POF was noted and surgical wound was inspected daily. Preoperative temperature readings were taken from the day of admission till the day of operation at 8 hourly intervals. Nonsteroidal anti-inflammatory drugs and steroids were not given because of their antipyretic effects. Patients' pre- and postoperative vital signs and other parameters were regularly monitored.

Temperature measurement/data collection

All the temperature measurement was recorded by the researcher using a proforma in a tabular form; postoperative temperature measurement was done using the same thermometer (Kaufman Flexible LED digital thermometer). The thermometer was disinfected after each use with 2% chlorhexidine gluconate in 70% alcohol. Patient's body temperature reading was taken 8 hourly daily. The average of the three daily temperatures was calculated and recorded as the day's body temperature. Axillary temperature measurement was taken for the purpose of this study because it is convenient and comparable to other methods.[13],[14],[15] All body temperature measurement was stopped on the day of patient's discharge.

For those whose rise in body temperature lasted 3 days, strict aseptic technique was used to collect three samples of 10 mls of blood from a peripheral vein and inoculated into a blood culture bottle (Oxoid SIGNAL® blood culture system) to culture for aerobic and anaerobic microorganisms.

Further investigative evaluation

Plain chest radiograph

Postoperative chest X-rays were requested for all patients with established fever, who had clinical findings suggestive of atelectasis or other pulmonary causes. All radiographs were taken at the radiology department of the hospital and interpretation done by the same radiologist.


Blood for malaria parasite was taken from all the patients at the time of collection of blood for preoperative hemogram and from those whose fever lasts up to 3 days after surgery.


Urine culture was to be performed for those with rise in body temperature and have indwelling urinary catheters lasting more than 72 h postoperatively.

Preparation of blood before transfusion

Donor blood for transfusion was grouped and cross-matched type for ABO and Rhesus compatibility and screened for HIV, Hepatitis B, Hepatitis C, and Syphilis in the hematology laboratory. Patient's information, blood group, blood bag number, and date of collection on the blood bag were cross-checked with that on the laboratory form to prevent transfusion of incompatible blood before transfusion.

Ethical consideration

Ethical clearance was obtained from the Health Ethics Committee of the UNTH. Written consent was obtained from all participants recruited after explaining the purpose of the study. In the case of underage patients, written consent was obtained from a parent and assent given by the child where possible.

Sample size determination

The sample size was determined using the formula for determination of minimum sample size in a descriptive study:


Where n is the minimum sample size per group, Zα is the standard normal deviate corresponding to the probability α (which is 1.96 at 95% confidence limit for a two-tailed test), and P is the estimated prevalence of POF in previous studies. d is the amount of error to accommodate at set confidence limit (CL 95% or 0.05). This is taken from a study by Adoga et al.[16] = 7.6.


N = (1.96)1.96 × (0.076 ×0.92) 0.052 = 108

Sample size determined was 108.

Statistical analysis/Data management/analysis

The Statistical Package for the Social Sciences (SPSS), software package version 21 for Windows (SPSS Inc., Chicago, USA), was used for data entry, validation, and analysis. All tests were two-tailed and P value was set at equal or less than 0.05 level of significance.


A total of 108 patients were recruited into this study, 70 males (64.8%) and 38 females (35.2%) with a ratio of 1.8:1. The mean age of the patients was 27.2 years (standard deviation 13.1). Twenty-three of them had postoperative. Blood transfusion was the commonest cause seen in this study contributing 11 (47.8%), followed by malaria parasite with 5 (21.7%). In three (13.0%) patients, the cause was unknown, whereas four (17.4%) had multiple causes. However, no patient had raised body temperature from urinary infection as none of those with POF had their urinary catheter in place for more than 72 h.


POF could be one of the unwelcomed complaints in patients following OMFS. Its management could pose a challenge to surgeons and other health-care providers.[5] A good understanding of the pathophysiology and pattern of presentation is important so as to know when further investigations, wait-and-watch approach, or intervention is needed.[13]

Blood transfusion showed significant association with POF in this study P = 0.001. Kennedy et al.[17] in their study of 90 patients that had total knee replacement surgery reported that the risk of developing fever increases four times for each unit of blood transfused. Zhao et al.[17] reported that the use of leucocyte-depleted blood has been found to be associated with reduced febrile nonhemolytic transfusion reaction.[18] Substances like cytokines are known to be released gradually in blood over time during storage which causes fever after blood transfusion.[19] The patients in this study were transfused whole blood instead of leucocyte-depleted blood; it is also a common practice to give blood to the patients stored for long. These may have accounted for this finding in this study.

From this study, the type of surgery performed appears to have a strong correlation (P = 0.008) with POF. A high frequency of fever was observed among those that had malignant tumor surgery as opposed to those who had benign tumor surgery [Table 1]. Walid et al.[20] reported that the type of surgery was the most important variable which affected the outcome of POF in their study. Miyawaki et al.[21] reported an association between elevations of plasma IL-6, a known pyrogenic cytokine with the magnitude of tissue damage in OMFS. The above finding may be because of the effect of these cytokines which are found to be more in malignant lesions.[22],[23] Furthermore, malignant lesions often involve extensive tissue manipulation and excision and it has been reported that the greater the surgical trauma, the more likely POF will occur.[24],[25],[26]{Table 1}

POF in majority of the patients commenced within the first postoperative day [Table 2]. This appears to agree with the findings in a number of other studies where most patients had maximum body temperature from the first postoperative day with normal temperature returning by the fourth postoperative day.[27],[28],[29] No case of POF was recorded beyond the fifth postoperative day in this study [Table 3]. This is believed to be because of inflammatory reactions, which occur immediately following acute injury. Also, the fact that most of the causes of POF in this study were of noninfective origin in which case POF is known to commence late and is of longer duration may have accounted for this.[16],[20]{Table 2}{Table 3}

A significant association between duration of surgery and POF (P = 0.001) was noticed in this study. Patients whose surgery lasted more than 120 min were noticed to have a greater risk of developing POF unlike those whose surgery lasted for 120 min or less [Table 4]. This finding is similar to a study done among children that had vascular surgeries which revealed that a prolonged duration of surgery was associated with increased risk of POF.[30] It is possible that with increased duration of surgery, more IL-6 is released as shown in the study by Satarri et al.[31] where they demonstrated a positive correlation of IL-6 plasma concentration with duration of surgery among 28 orthognathic surgery patients.{Table 4}


This study found that most cases of POF are of early onset and of short duration. The longer the surgery time, the more likely POF will occur.

Ethical approval

The Health Ethics Committee of the UNTH approved this work (ethical clearance certificate reference number NHREC/05/01/2008B-FWA 00002458-1RB00002323).

Patient consent

Written consent was obtained from the patients for the purpose of the surgical treatment and to publish the outcome of the study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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