Introduction
Local anaesthesia results from the inhibition of all sensation, including pain, from an area of the body without the loss of consciousness. This was first practiced in Peru by the ancient Incas,(1) who used cocoa leaves as a local application to relieve pain. By the 1800s, extracts from the coca plants had been introduced into Europe. In 1860, Albert Nieman isolated an active ingredient from coca leaves, calling this ‘cocaine.’ Sigmund Freud used cocaine in psychoanalysis, and William Halsted used nerve blocks. Both these researchers developed a cocaine use disorder.(2)
The search for a non-addictive local anaesthetic led to the discovery of lignocaine, a derivative of cocaine, in 1943 (3,4) and then to the formulation of bupivacaine, a longer-acting local anaesthetic, in 1957.(5) The combination of lignocaine with adrenaline can provide both local anaesthesia and a bloodless field without the need for a tourniquet.(6) Combining the conventional lignocaine with adrenaline mixture with the longer-acting bupivacaine is described for more complex and more painful procedures.(7) The safe dose for lignocaine with adrenaline is 7mg/kg, and for bupivacaine with adrenaline is 2mg/kg.
Hand operations performed for patients in the Hand Surgery Unit at CMJAH are routinely done using a regional nerve block combined with a tourniquet to achieve a bloodless operative field. The local anaesthetic is lignocaine, with bupivacaine added for more prolonged procedures.
Wide awake local anaesthetic without tourniquet (WALANT) in which the vasoconstrictor effect of adrenaline is combined with lignocaine avoids the need for a tourniquet (6) which is often poorly tolerated (8) and can lead to neurological damage.(9) Moore et al. (1978) identified bupivacaine with adrenaline as a safe method for local anaesthesia.(10)
The current study evaluated two anaesthetic techniques: bupivacaine with adrenaline (WALANT Test Group A) and compared a specific nerve block with lignocaine and tourniquet (Control Group B).
Parameters assessed included pain control, haemostasis, time efficiency, and toxicity.
Method
Seventy-two adult patients undergoing hand surgery for traumatic injuries or elective indications, for which local anaesthesia was appropriate, were randomly assigned to Group A or Group B. Bupivacaine with adrenaline (WALANT Test Group A) was compared with regional anaesthesia using a specific nerve block such as axillary, wrist block or digital with lignocaine and tourniquet (Control Group B).
In the WALANT group, bupivacaine with adrenaline was infiltrated subcutaneously in the surgical site where anaesthesia was required. In the control group, the tourniquet pressure was 100 mm Hg above systolic blood pressure. Tourniquet pain was anticipated and managed by selecting an axillary block for complex injuries requiring long surgical times and deflating and reinflating the tourniquet.
Exclusion criteria were not limited to polytrauma patients, severe medical comorbidities, and patients using anticoagulants or medication that affected clotting. Trauma operations performed in both groups were, among others, hand fracture fixations with k-wires, open reduction and internal fixation (ORIF), multiple tendon repairs, vessel and nerve repairs, and reconstructions, including simple and complex repairs. Elective operations performed in both groups included carpal tunnel releases and hand mass excisions. Each group comprised equal numbers of trauma cases and elective operations, randomly allocated to the following groups: the first 36 patients to Group A and the following 36 to Group B. The safe dosage for lignocaine with adrenaline was 7mg/kg, and bupivacaine with adrenaline 2mg/kg was adhered to.
Four essential parameters were assessed for each patient:
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Control of intraoperative pain measured by the numerical pain grading scale (NPGS).(11)
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Excessive bleeding obscures the operative field. Thus, the number of abdominal swabs (20cm x 20cm) was used.
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Time taken from the initial incision to a bloodless field.
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Toxicity: central nervous system (CNS), cardiovascular system (CVS), anaphylactic symptoms.
Statistical analysis
The relationship between two categorical variables was assessed using Pearson's chi-square test with respect to the grading of pain and its association with excessive bleeding.
The independent sample t-test was used to identify time efficiency regarding the time from the first incision to achieve a bloodless field.
Ethical approval was obtained from the WITS Human Research Ethics Committee.
Results
Demographics
Patients in the trauma categories were predominantly young men (Table 6.1). In the elective categories, 25% were patients aged 50 to 59, with 36% female.
Patient characteristics by gender, type of surgery, and age.
| Characteristic | Group | Type of surgery | |||
|---|---|---|---|---|---|
| Group A (n = 36) | Group B (n =36) | Elective (n =36) | Trauma (n =36) | ||
| Gender | Female | 27.8 (n =10) | 13.9 (n =5) | 36.1 (n =13) | 5.6 (n =2) |
| Male | 72.2 (n =26) | 86.1 (n =31) | 63.9 (n =23) | 94.4 (n =34) | |
| Total | 100% | 100% | 100% | 100% | |
| Age category | 20–29 | 25.0 (n =9) | 25.0 (n =9) | 16.7 (n =6) | 33.3 (n =12) |
| 30–39 | 22.2 (n =8) | 38.9 (n =14) | 16.7 (n =6) | 44.4 (n =16) | |
| 40–49 | 22.2 (n =8) | 13.9 (n =5) | 22.2 (n =8) | 13.9 (n =5) | |
| 50–59 | 13.9 (n =5) | 11.1 (n =4) | 25.0 (n =9) | 0.0 (n =0) | |
| 60- | 16.7 (n =6) | 11.1 (n =4) | 19.4 (n =7) | 8.3 (n =3) | |
| Total | 100% | 100% | 100% | 100% | |
Haemostasis
The degree of bleeding was gauged from the number of abdominal swabs needed to control bleeding in the operative field. Nine patients in Group A (9/36 (25%)) experienced excessive bleeding compared with the two patients in Group B (2/36 (5.5%)) (Table 6.2).
Excessive bleeding for group A and group B.
| Observed frequencies | Groups | |||
|---|---|---|---|---|
| Group A | Group B | Total | ||
| Excessive bleeding | Yes | 9 | 2 | 11 |
| No | 27 | 34 | 61 | |
| Total | 36 | 36 | 72 | |
Both groups of patients required the use of abdominal swabs. However, the WALANT Group A required significantly more swabs than the tourniquet Group B (9:2 (p =0.02)) (Table 6.3).
Time efficiency
The time taken from induction of anaesthesia to the first incision was similar in both groups, but additional time was needed to achieve a bloodless operative field in Group A. However, the total time from the first incision to haemostasis was not significantly different between the two groups (Independent sample t-test p =0.13) (Table 6.4). The duration of surgeries was between 10 minutes and 3 hours, 30 minutes.
Total time-independent samples t-test data.
| Independent Samples Test | Levene's Test for Equality of Variances | t-test for Equality of Means | |||||||
|---|---|---|---|---|---|---|---|---|---|
| F | Sig. | T | Df | Sig. (2-tailed) | Mean Difference | Std. Error Difference | 95% CI of the Difference | ||
| Lower | Upper | ||||||||
| Equal variances assumed | 3.086 | 0.083 | 1.522 | 70 | 0.133 | 1.139 | 0.749 | -0.354 | 2.632 |
| Equal variances not assumed | 1.522 | 64.386 | 0.133 | 1.139 | 0.749 | -0.356 | 2.634 | ||
Discussion
Many operations in hand surgery are performed under local anaesthesia, which has the advantages of minimal preoperative preparation, avoiding fasting, and interrupting oral medical therapies. It also reduces the incidence of nausea and vomiting and offers the intraoperative assessment of repair in a conscious patient.
Whichever technique is used for local anaesthesia, pain control, and a bloodless operative field is mandatory.
In this small study, regional nerve blockade with tourniquet control of bleeding was compared to subcutaneous injections of bupivacaine with adrenaline added for the vasoconstrictive effect. The results showed that pain control was similarly effective in both patient groups, irrespective of the indication for hand surgery.
However, bupivacaine with adrenaline was less effective in the prevention of bleeding than a tourniquet, confirming the findings of Farzam et al.(12) International researchers have advised a 30-minute waiting time after injection to achieve the full vasoconstrictive effect of adrenaline before commencing the operation.(13,14)
In the current series, a ‘time efficiency’ review showed that the average ‘wait time’ before the first incision was only 15 minutes. This short ‘wait time’ may have resulted in more time than was spent in achieving a bloodless field, confirming the importance of the 30-minute waiting time to achieve adrenaline vasoconstriction. The best way to save theatre costs would indeed be to inject the patient at least 30 minutes before the first incision. Due to the longer duration of action, bupivacaine does not wear off as quickly as lignocaine, and no top-up injections will be required, further saving costs. The one patient in the WALANT group who required six abdominal swabs to maintain a bloodless field highlights the importance of not excluding a history of bleeding, anticoagulant history, and use of herbal medication, which the patient or clinician may easily forget.
No patient suffered central nervous system or cardiovascular or anaphylactic symptoms of toxicity in the current series. Bupivacaine is longer-acting and more cardiotoxic than lignocaine.(7)
Care not to exceed the bupivacaine with adrenaline maximum dose of 2mg/kg, as well as care to avoid intravascular injections, will ensure safe local anaesthetics. Moore et al. (1978) reviewed over 11 000 cases where bupivacaine was used and noted that this provided a safe anaesthetic (10).
Conclusion
When a local anaesthetic is indicated for patients undergoing hand surgery, bupivacaine with adrenaline is a safe and effective local anaesthetic. Pain control is reliable and more prolonged than lignocaine, provided time is allowed after the injections for the optimal vasoconstrictive effect of adrenaline and a resultant bloodless operative field. However, for patients with a history of bleeding or anticoagulant therapy, tourniquet control should be substituted for adrenaline. More extensive future studies are required to validate the data.