AN AUDIT OF ORAL AND MAXILLOFACIAL PROCEDURES UNDER GENERAL ANAESTHESIA AT THE UNIVERSITY COLLEGE HOSPITAL IBADAN, NIGERIA

Abstract

Background

Operating theatre time management is a constant source of tension among the healthcare professionals responsible for the use of the facility. It is important that all effort should be geared at optimal utilization of available resources and minimization of waste.

Aim

To appraise time management, frequency and duration of surgical procedures, frequency and determinants of blood transfusion in oral and maxillofacial surgery

Design of the study

Prospective clinical study

Setting

The University College Hospital, Ibadan. Nigeria.

Methodology

This was a cross-sectional study of consecutive patients who had maxillofacial surgical procedures. Information was collected on number of cases scheduled per list, number of cases done per list, each patient’s biodata, time intervals between patient arrival and departure from operating theatre, route and duration of intubation, type of surgical procedure, surgical time, preoperative and postoperative packed cell volume estimations, volume of blood loss and the frequency and volume of blood transfusions.

Results

The main points of delay were identified as the patient wait at the theatre reception and in the operating suite before intubation. Mandibulectomy procedures were the longest procedures with approximately five (5) hours, followed by maxillectomy with four (4) hours and maxillofacial trauma with three and a half (3.5) hours. Maxillectomy procedures had highest transfusion probability. The surgical time and the estimated blood loss significantly determined whether a patient would be transfused or not. The nasotracheal was the commonest route of intubation while cleft surgeries were the most frequent procedures performed followed by trauma surgeries. Majority of the patients were not transfused and two units of blood was the most frequent transfused volume for a patient.

Conclusion

The main areas of delay have been identified as patients’ waiting periods before the surgical procedures. The reasons why these delays occur need to be investigated and addressed to have an optimally functional facility. Reservation of blood for maxillofacial surgical procedures should be based on the anticipated need for blood transfusion for the particular procedure.

Introduction

Surgical audit is described as a systematic, critical analysis of the quality of surgical care that is peer reviewed against unambiguous criteria or agreed standards. It is employed to further inform and improve surgical practice with the ultimate goal of improving the quality of care for patients1. The eventual purpose of an audit is to examine whether what we think is happening is really happening and whether current performance meets existing standards1. An inefficient theatre can be a source of both wasted resources and frustration to patients and theatre staff alike2.

Planning surgical interventions requires a thorough knowledge of perioperative surgical timings and blood transfusion requirements to prevent life threatening complications. Surgeons, anaesthetists and other stakeholders may employ such knowledge during pre-operative counselling sessions, to inform proper theatre space scheduling and for reservation of blood and blood products. Surgical audits provide data for objective recommendations on the formulation of operating surgical protocols and policies to improve perioperative surgical patient care3,4.

While it is envisaged that hospitals in our environment should undertake surgical audits routinely to improve surgical care, this study can serve as preliminary undertaking towards comprehensive surgical audits. The study is a clinical audit aimed at investigating the operating theatre time and evaluating the perioperative blood transfusion pattern for oral and maxillofacial surgical procedures in a Nigerian tertiary hospital.

Materials & Methods

All consecutive and consenting patients who had oral and maxillofacial surgical procedures done under general anaesthesia between July 2011 and June 2012 were prospectively recruited into the study. The Oral and Maxillofacial department of the University College Hospital, Ibadan, as at the time of this study, was allotted a theatre suite once a week.

Information was obtained on number of cases scheduled per list, number of cases done per list, patient’s biodata, time intervals between patient arrival and departure from operating theatre, route and duration of intubation (length of time between pre-oxygenation and securing an endotracheal tube in situ), type of surgical procedure, time of ‘knife on skin’ (start of surgery), time the last suture was placed (end of surgery), surgical time (length of surgical procedure), preoperative and postoperative packed cell volume estimations, volume of blood loss and the frequency and volume of blood transfusions.

The time values were obtained in the 24-hour format and recorded in minutes to enable data analysis and subsequently converted to the 12-hour format for presentation where indicated.

The theatre utilization was calculated as the sum of the mean surgical time and intubation time divided by the potentially available theatre time multiplied by 1005>.

Blood loss was estimated by counting the number of soaked gauze pieces - the 10cm x 10cm gauze was estimated to hold about 10mls of blood while the 30cm x 30cm was estimated to hold about 100mls of blood – and measuring the suctioned blood while adjusting for fluid irrigation, blood soaked by the drapes as well as the blood on the operators’ gowns during the surgical procedure6,7.

Blood transfusion parameters were documented as:

• •Transfusion probability (%T): The probability of transfusing a patient for a particular surgical procedure. This was calculated as = Number of patients transfused/Number of patients cross-matched x 100. A value greater than 30% is indicative of significant blood usage⁸.
• •Transfusion index (TI): The average number of units used per patient cross-matched and it is indicative of the appropriateness of the number of units ordered. It was calculated as = Number of units transfused/Number of patients cross-matched. A value greater than 0.5 is indicative of significant blood usage⁹.

Data collected was analysed using SPSS version 20. Tables and figures were generated following univariate analysis and means were compared using Independent T-test for two means and ANOVA for comparison of multiple means. Significance was set at p<0.05.

Results

One hundred and eight patients were operated on out of the 139 patients scheduled for maxillofacial surgery within the one-year study period, giving a cancellation rate of 22.3%. There were 61 males with a male to female ratio of 1.3:1. The mean age was 23.2 years (SD ±19.7), while the median age was 21 years. Ninety cases were done as first case of the day with no more than two cases per day. Only 8.3% of the patients had background systemic illness (hypertension). The commonest route of intubation was nasotracheal (55.6%) while tracheostomy served as airway access in only 3.0% of the cases as shown in Fig. 1. Cleft lip repair was the commonest procedure followed by trauma with 22 (20.4%) cases and 18 (16.7%) cases respectively (Fig. 2).

The mean time for a first case patient arrival at the theatre reception was 8.23hr (493.9 minutes, SD±65.810) while surgical procedures started at a mean time of 11.59hr (695.9 minutes, SD ±81.861) and the mean time for the end of surgery was 14.46hr (886.3 minutes, SD ± 131.9). The time values for first case and second case patients’ movement were compared and are as shown on Table 1. Both first and second case patients waited over half an hour at the reception as well as in the surgical suite before intubation. The first case patients waited significantly longer than the second case patients at both points. The mean time intervals for interventions according to the types of surgical procedures are as depicted on the Table 2. Maxillectomy procedure had the longest intubation time with 59.2 minutes (SD±44.2), cleft palate repair had the shortest with 32.6 minutes (SD±11.8). The time for tumour delivery was longest with mandibulectomy alone (163.0 minutes, SD±63.6) and the time for wound closure (which included reconstructions where applicable) was longest for mandibulectomy with iliac crest (nonvascularised) bone graft 172.2 minutes (SD±81.1). Mandibulectomy alone was the longest procedure overall with 300.8 minutes (SD±111.0) followed by mandibulectomy with iliac crest (nonvascularised) bone graft reconstruction (Table 2). The mean surgical time for all cases combined was 181.4 minutes (3 hours).

Table 1: Time points and period for first case and second case procedures.

	Case	Mean time	Std. Deviation	Sig
Arrival time in theatre	First	493.9mins	65.810	0.000*
	Second	802.6mins	74.897
Wait at reception	First	121.3mins	83.180	0.000*
	Second	44.7mins	36.674
Wait in suite before procedure	First	40.2mins	27.309	0.009*
	Second	28.8mins	13.735
Intubation procedure	First	40.2mins	18.465	0.112
	Second	32.5mins	18.656
Start of surgery	First	695.9mins	81.861	0.000*
	Second	908.6mins	63.776
Surgical time	First	186.5mins	108.497	0.255
	Second	155.8mins	75.661
End of surgery	First	886.3mins	131.884	0.255
	Second	1,070.9mins	107.761
Wait in suite after procedure	First	26.8mins	18.151	0.00*
	Second	25.7mins	14.732
*Statistically significant. (Time in minutes using the 24-hour format)

Table 2: Time durations and interventions according to types of surgical procedures in minutes.

Type of surgical procedures (Number of cases)	Mean Waiting time in reception (SD)	Mean Waiting time in suite (SD)	Mean Intubation time (SD)	Mean time for tumour delivery (SD)	Mean reconstruction and wound closure time (SD)	Mean total Surgical time (SD)	Mean waiting time in suite after surgery (SD)
All cases (108)	108.5 (82.4)	38.7 (25.9)	38.9 (18.6)	103.7 (65.5)	109.2 (67.5)	181.4 (104.1)	26.6 (17.6)
Cleft lip repair (22)	82.0 (48.4)	36.3 (19.4)	40.3 (17.4)	-	-	128.8 (44.5)	24.4 (16.2)
Cleft palate repair (14)	139.9 (107.2)	36.9 (23.4)	32.6 (11.8)	-	-	135.0 (53.9)	31.1 (13.7)
Mandibulectomy alone (13)	107.8 (48.8)	48.8 (32.2)	47.5 (18.3)	163.0 (63.6)	137.8 (63.0)	300.8 (111.0)	26.0 (17.5)
Mandibulectomy and bone graft (7)	161.4 (98.5)	44.6 (46.4)	39.0 (12.8)	133.3 (41.5)	172.2 (81.1)	286.1 (109.7)	20.6 (5.7)
Maxillectomy (5)	208.0 (130.3)	35.6 (7.1)	59.2 (44.2)	92.8 (37.7)	152.0 (45.0)	244.8 (70.4)	24.4 (5.3)
Trauma (18)	106.5 (82.9)	29.1 (25.0)	34.8 (16.0)	-	-	213.8 (106.2)	20.2 (9.9)
Minor surgical procedure (17)	104.7 (80.6)	38.7 (21.9)	33.3 (19.5)	68.8 (47.4)	51.5 (19.5)	124.5 (76.7)	33.6 (27.2)
Tumour excision (12)	64.5 (55.3)	45.3 (27.5)	38.8 (12.8)	56.3 (40.6)	70.7 (40.7)	143.6 (90.0)	30.9 (22.7)

The theatre utilization rate was calculated on an assumption that eight hours (8:00hr to 16:00hr) of theatre time was potentially available per theatre session. The overall mean surgical time of 3 hours therefore translated to a theatre utilization rate of 37.5%.

Blood was routinely grouped and cross-matched for all patients preoperatively. A total of 13 patients were transfused with a sum of 25 units of blood giving a transfusion probability of (%T) of 12.0% and a transfusion index of 0.23. Eighty-eight percent of the patients had no need for intraoperative whole blood transfusion while less than 9% required transfusion of 2 or more units of whole blood (Figure 3). Maxillectomy and mandibulectomy procedures had the highest transfusion probability of 60.0% and 53.8% respectively (Table 3). Amongst the transfused cases two units of blood was the most frequently transfused volume per patient accounting for 46.2% of the transfused cases.

Table 3: Means of transfusion related perioperative parameters.

Procedure (Number of cases)	Mean pre-operative PCV (±SD)	Mean post-operative PCV (±SD)	Mean estimated blood loss in mls (±SD)	Number of patients transfused	Transfusion probability(%T)	Number of units transfused	Transfusion Index(TI)
All cases (108)	36.8 (4.7)	34.8 (5.2)	327.5 (115.0)	13	12.0%	25	0.23
Cleft lip repair (22)	33.6 (3.6)	32.6 (3.3)	35.0 (27.5)	0	0	0	0
Cleft palate repair (14)	35.8 (3.4)	33.3 (3.2)	108.6 (101.7)	0	0	0	0
Mandibulectomy alone (13)	37.5 (3.9)	34.0 (4.2)	1,077.7 (787.4)	7	53.8%	11	0.85
Mandibulectomy and bone graft (7)	40.3 (2.0)	33.9 (6.6)	788.6 (316.8)	2	29.0%	2	0.29
Maxillectomy (5)	35.4 (7.6)	34.0 (2.0)	744.0 (268.6)	3	60.0%	8	1.6
Trauma (18)	37.4 (4.6)	35.1 (5.4)	146.8 (132.1)	1	5.6%	2	0.11
Minor surgical procedures* (17)	37.9 (5.7)	36.0 (6.1)	271.7 (359.6)	0	0		0
Tumour excision (12)	39.0 (4.6)	38.6 (6.6)	199.6 (119.2)	0	0		0
*Such as multiple tooth extractions and cyst enucleations.

Table 4 shows the possible differentiating parameters between the patients who were transfused and those who were not, the possible effects of the nature of the lesion on the surgical time and estimated blood loss (EBL) and the extent of the lesion on the surgical time and the EBL. The surgical time and the EBL were higher in those who were transfused and this was statistically significant (p=0.0001). The nature of the disease did not appear to affect the surgical time (p=0.580) nor the EBL (p=0.080).

Table 4 : Comparison of means to show the effect of width of lesion, surgical time and EBL on transfusion and nature of lesion.

	Transfusion	% Cases	Mean	Std. Deviation	Sig
Width of lesion	Yes	9	11.01 cm	5.842	0.171
	No	28	7.96 cm	3.666
Surgical time	Yes	13	322.1 mins	91.351	0.000*
	No	95	162.1 mins	90.292
EBL	Yes	12	1,273.3 mls	621.981	0.000*
	No	94	206.7 mls	282.790
	Nature of lesion	% Cases	Mean	Std. Deviation	Sig
Extent of lesion	Benign	25	8.3 cm	4.015	0.303
	Malignant	8	10.3 cm	5.946
Surgical time	Benign	30	218.2 mins	131.423	0.580
	Malignant	10	243.8 mins	105.163
EBL	Benign	30	504.5mls	402.553	0.080
	Malignant	10	1,081.0mls	909.157
*Statistically significant.

Discussion

This study was conducted to appraise the theatre time management, the frequency and duration of surgical procedures, and the frequency and determinants of blood transfusion in oral and maxillofacial surgery. Patients’ wait at the theatre reception and in the operating suite before intubation were identified as the significant points of delay. Mandibulectomy procedures were the longest of the procedures and maxillectomy procedures had highest transfusion probability. Also, majority of the patients were not transfused and two units of blood was the most frequent transfused volume for a patient.

Operating theatres’ cost is a huge investment of healthcare resources; this cost sometimes approximates one-third of total hospital budget9. There is therefore an increasing interest in providing an “efficient” anaesthetic and surgical service, to make surgical operations the largest potential source of income for the hospital. This study reported a case cancellation rate of 22.3% in scheduled elective oral and maxillofacial surgical procedures. However, case cancellations on the day of surgery, due to suboptimal utilization of theatre time, is a well- recognized problem in hospitals, ranging from 10% to 40% across different health care systems worldwide, 60% of these case cancellations could potentially be avoided10.

Managing time spent in an operating theatre is important as good time management improves the number of cases done per each surgical session. In his editorial on “how much an OR time cost”, Macario implored that most hospitals should perform all cases scheduled provided a case can be done safely as determined by the anaesthetist. The operating room time has been reported to cost $62 to $100 per minute11,12. Therefore, being able to clear a surgical list is of significant economic value. This enhances growth and development (including personnel) and fosters the reputation of the facility positively. It should be contemplated that all the time a surgical facility is kept opened should be accounted for. From the findings of this study majority of the theatre sessions had only one case operated. The theatre utilization rate of 37.5% observed in this study is low compared to 50% to 60% theatre utilization of some other centres striving to improve their theatre utilization rates13. Furthermore, the combined waiting period after patients’ arrival in the theatre complex from the ward (wait at reception and wait in the suite) was about 2.5 hours (Table 1). These waiting periods are higher than some reported values for similar time periods where the average waiting time was less than 30 minutes and has even been reported to be less than 10 minutes in some studies2,14. It was also noted that the first case patients waited longer at the reception than a second case patients as shown in Table 1. The reasons for this underutilization and unnecessary waiting times need to be investigated and addressed in order to harness the benefits enumerated above. Amongst possible reasons for a surgical facility underutilization is case cancellation15. Possible reasons for case cancellation have been cited as lack of operating time, lack of patient fitness for surgery, non-attendance of patients and unavailability of blood15. The cancellation rate was observed to be slightly high in this study as almost a quarter of scheduled cases were cancelled and may have contributed to the underutilization observed. A similar study from a high volume theatre complex in the UK recorded a cancellation rate of about 17.26%5. Cancellation weakens the cost-benefit of running a surgical facility by increasing the cost of patient care. It is also a source of psychological trauma as well as financial loss to patients and patient relatives or caregivers since additional time will have to be obtained to be away from work15,16. It is therefore suggested that surgical lists should be considered carefully and when possible with the anaesthetists’ input to reduce cancellation rate and waste of theatre time.

Time utilized for a surgical procedure as an entity will logically vary according to the procedure being done. The longest surgical time seen in this study is similar to previous reports where it was noted that the longest surgical procedure was associated with extensive soft tissue dissection and bone resection¹⁷. This is reflected in this study by the surgical time for jaw resections being longer than other procedures (Table 2). Also noted was the longer surgical time for large lesions, as these will require extensive soft tissue dissection (Table 4). Despite the prolongation of surgical time by the extent of lesion notwithstanding, appropriate instrumentation and minimization of distractive tendencies during operative procedures can improve surgical time management18.

Estimation of intraoperative blood loss is largely subjective and may suffer from inter observer variability and poor repeatability19. This variability may account for the differences in the estimated blood loss in this study compared with some earlier reports17,20. However, the blood loss for jaw resections in this study was similar to that reported in a previous study on orthognathic procedures21. Also the surgical time appear to correlate with the blood loss estimation as supported by an earlier report21.

The maxillofacial region is a highly vascularised region. It is therefore logical to preoperatively group and cross match adequate units of blood prior to maxillofacial procedures. However, over-ordering of blood for elective surgeries appears to be a common practice9,22,23. When blood is ordered, reserved and not used it loses shelf life, it is a source of inventory problems for blood banks and most crucially it is not available for other needful patients. Considering the finite nature of blood as a resource with a limited shelf life and associated considerable processing costs, utilization of this resource needs critical review19.

In addition, perioperative blood transfusion may increase the risk of transmission of blood-borne viral pathogens and risk cancer recurrence due to transfusion related immunomodulation3. The question then arises if it is necessary to routinely cross-match blood for all maxillofacial procedures? Soni et al23 in the evaluation of transfusion protocol in maxillofacial surgery suggested that preoperative grouping and cross-matching should be reserved for major maxillofacial cases such as excision and reconstruction in the management of large pathologies. The overall transfusion probability, which is an indication of blood usage, was found to be low in this study compared to a similar study in which jaw resections accounted for 74.1% of the surgical cases analysed24.

However, the transfusion probabilities for particular procedures like mandibulectomies and maxillectomies were similarly high23,24. The comparison of cases that were transfused against those that were not transfused showed that the estimated blood loss and surgical time were significantly higher in the cases that were transfused, implying that the anticipated surgical time and estimated blood loss may predict whether or not a patient may require blood transfusion (Table 4). Oral and maxillofacial cases which require less than 3 hours of surgical time and do not involve osseous surgeries, like cleft repairs may not require blood transfusion (Table 3). This finding is supported by some other studies where none of the 116 infants and 41 patients, respectively, who had cleft lip and palate surgery required blood transfusion17,35. It is therefore suggested that preoperative blood cross-matching and reservation should be restricted to maxillofacial procedures with %T of 30% or more, estimated surgery time >5 hours, extent of tumour ≥ 10cm and anticipated blood loss of >500mls. These are arbitrary guidelines based on this study; randomised studies will be required to determine accurate predictors of the need to transfuse during maxillofacial procedures.

However, all patients should have their blood routinely typed, screened and saved preoperatively in case of emergency situations8. Also, tranexamic acid can be advocated for high volume procedures like maxillectomy and mandibulectomy as this drug is known to reduce blood loss during surgical procedures26. This will also reduce the need for blood transfusion. Tools such as electro-cautery and harmonic scalpels have been shown to significantly reduced the amount of surgical wound hemorrhage. Basic surgical technique and care for soft tissues will avoid unnecessary trauma and injury to microvasculature. Simple considerations such as operative time management and operative approach, also contribute, as it is well accepted that duration for which a surgical wound is open is directly related to the need for the transfusion of blood products27. In circumstances where the blood transfusion will be required in elective cases, autologous blood transfusion may be more appropriate than a ‘cross-match’ policy4 in order to further reduce overall cost to the facility and the patient.

Conclusions

The main areas of delay have been identified as patients’ waiting periods before the surgical procedures. The reasons why these delays occur need to be investigated and addressed to have an optimally functional facility. Reservation of blood for maxillofacial surgical procedures should be based on the anticipated need for blood transfusion for the particular procedure.

Fig. 1: Route of intubation.

Fig. 2: Type of primary procedure.

Fig. 3: Transfusion pattern.