Distal Intravenous Regional Anaesthesia for Claw Diseases in Bovines

Claw diseases are common in dairy cattle and can be treated in their early stages by therapeutic claw trimming (Thomas et al., 2016). Intravenous regional analgesia is safe, reliable and cost-effective technique for providing anesthesia as well as bloodless short surgical procedures of extremities (Lumb and Jones, 1984). Bier’s block can easily be used in field condition with minimum facility available. The disadvantages include local anesthetic (LA) toxicity, poor muscle relaxation, tourniquet pain and minimal postoperative analgesia (Muhammad and Muhammad, 2012). The ideal IVRA solution should have rapid onset, require less dose of local anesthetic (LA), reduce tourniquet pain and prolong post-deflation analgesia. This may be achieved by addition of adjuncts to LA (Kognole et al., 2004). In presently available technique of IVRA, the tourniquet is placed at the mid metacarpal/ metatarsal region and large amount of local anesthetic is needed which sometimes may lead to local anesthetic toxicity during release of tourniquet (Skarda, 1987). Signs of toxicity can include drowsiness, minor convulsions and seizures, trembling and profuse salivation with hypotension (Weaver et al., 2005).
       
To overcome this problem, dose of the local anesthetic can be reduced by applying tourniquet just below the dew claws. No study till date has been undertaken on lower IVRA in bovines. Due to the paucity of literature on this aspect, the current study is designed to compare the efficacy of different doses of lignocaine hydrochloride for standard IVRA with modified IVRA.

The present study was conducted on the cattle having different surgical ailments of hoof/digit. The cattle having claw disease(s) were divided in to two groups having six animals/limbs in each group. The animals were prepared as per routine surgical procedure. The affected animals were off fed for overnight and limb was shaved below the level of knee/ hock. No premedication was given to any of the animal. Animals were casted and restrained in right lateral recumbency with affected limb upper most. The site was prepared aseptically and the area was painted with antiseptic solution. Intravenous regional anesthesia was induced as per the standard technique in group I animals (Yavari et al., 2017). Briefly, tourniquet was placed circumferentially in the middle of the metacarpus (Fig 1). Butterfly canula was placed in the radial vein and the area was exsanguinated. However in group II animals, tourniquet was applied just below the dew claws and butterfly canula was placed in the axial digital vein (Fig 2). Lignocaine hydrochloride was injected @ 4mg/kg b.wt. and 2mg/kg b.wt. in group I and II animals, respectively. After removing the needle, injection site was compressed with povidone iodine soaked cotton swab for about 1 minute to avoid unintended drainage of the local anaesthetic from the punctured vein or formation of a haematoma. The anesthetic potency was monitored by observing the following parameters: 
 

 

 
Heart rate
 
Heart rate is the speed of the heartbeat measured by the number of contractions of the heart per minute. Heart rate may vary according to body’s physical need. Heart rate was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 
Pulse rate
 
Pulse rate represents the tactile arterial palpation of the heart beat. It can be palpated from middle coccygeal artery located on the ventral surface of the tail by fingers. It is recorded as beat per minute (bpm). Pulse rate of animals was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 
Respiration rate
 
It is measurement of frequency of breathing. It is usually measure as breath per minute. For a healthy animal it should be 12-18 per minute. It was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 
Peripheral oxygen saturation (SPO2)
 
It is percentage of hemoglobin binding site in the blood stream occupied by oxygen. It is measure by the small device called pulse oxymetry (Marketed by- Dr. Trust, Model no. DR50D, Nectar Life science Limited Works, Saidabad, Mohali, Punjab). The device was applied at the tip of the ear (Fig 3) and the reading was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 

 
Systolic pressure
 
It is pressure within arteries. It was measured by non invasive blood pressure monitoring unit (Romsons BPX automatic BP monitor) and is measured in mmHg (Fig 4). It was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 

 
Diastolic pressure
 
It is also measurement of pressure within arteries in diastolic phase. It was measured by non invasive blood pressure monitoring unit (Romsons BPX automatic BP monitor) and is measured in mmHg (Fig 4). It was taken preoperatively, 5, 10, 15, 20, 30, 40, 50, 60 minutes or till the recovery and after removal of tourniquet.
 
Sensory block onset time
 
It is from the time of drug injection to sensory block achieved in all dermatomes. It is measurement of sensory blockade. It was taken at 5, 10 and 15 minutes  after the administration of anesthesia as per method described by Kognole et al., (2004). Briefly, sequential loss of reflexes were recorded by making repeated pin pricks over the skin below the tourniquet at specific time intervals (not more than 2 to 3 times at a given space).
 
Motor block onset time
 
It is measurement of motor blockade. It was taken at 5, 10 and 15 minutes after the administration of anesthesia as per method described by Kognole et al., (2004).
 
Sensory block recovery time
 
It was measured after 30 minutes of administration of anesthesia at every 10 min interval till the recovery after the administration of anesthesia as per method described by Kognole et al., (2004). Briefly, the return of reflexes was ascertained by pricks of Robert-Jones towel clamp.
 
Motor block recovery time
 
It was measured after 30 minutes of administration of anesthesia at every 10 min interval till the recovery after the administration of anesthesia as per method described by Kognole et al., (2004).
 
Complication
 
Any sign and symptom of local anesthesia toxicity like regurgitation, pain, skin rashes, bradycardia, tachycardia, hypotension and convulsion was vigilantly looked.
 
Statistical analysis
 
One way ANOVA (Analysis of variance) was used to compare the mean values at different intervals with their base values. Independent “t” test was used to compare the mean values between groups at different intervals.

Bovines are prone to claw diseases such as sole ulcers, white line disease and inflammation of the adjacent soft tissues (Cook et al., 2016). Surgical correction of these ailments are painful and require adequate intraoperative and postoperative pain management including local anaesthesia (LA) and analgesic administration to control pain (Janssen et al., 2016). Intravenous regional anesthesia (IVRA) or Bier’s block is useful for short surgical procedures of the extremities for an anticipated duration of 60 to 90 minutes (Brown et al., 1989). The dose of Lignocaine hydrochloride was decreased to 2mg/kg b.wt. in group II animals because the area to be desensitize is decreased in distal IVRA as compared to proximal IVRA. Low dose of LA may also decrease the chances of toxicity during release of tourniquet. Toxicity in early tourniquet removal is avoided if the tourniquet is loosened for 10 to 15 seconds and retightened for 2 to 3 minutes and this procedure is repeated several times (Skarda, 1987). In lower IVRA technique, tourniquet may be released at once without any local anesthetic toxicity symptoms. 
       
Mean ± SE of heart rate (per minute), pulse rate, respiration rate, peripheral oxygen saturation (%), systolic pressure (mm of Hg)  and diastolic pressure (mm of Hg) of animals of different groups at different time intervals is presented in Table 1.
 

       
In group I the heart rate increased significantly (P< 0.05) at 20 and 30 minutes. Thereafter, the heart rate was more or less similar to base value. Significant increase in heart rate in group I animals might be due to tourniquet pain. A significant (P < 0.05) increase in heart rate was also noted after IVRA (Yavari et al., 2017). Increase in heart rate may be due to restraining of animals in lateral recumbency. Restraining of the animal induce stress response as indicated by an increased heart rate (Rizk et al., 2012).
       
Pulse rate increased significantly (P < 0.05) at 20 minutes and 30 minutes in group I and group II animals, respectively. Significant increase in pulse rate might be due to tourniquet pain caused by stimulation of sympathetic (autonomic) nervous system by electrical pain signals that reach the central nervous system.
       
There was no significant change in respiration rate in both groups. The IVRA tourniquet was removed just after recovery from motor block and the animals were returned from lateral recumbency to standing. Respiration rate was significantly decreased after removal of tourniquet in group I animals. However, no significant change in respiration rate was observed in group II animals. A significant decrease in respiration rate over time after removal of tourniquet from IVRA using 2% procaine was also observed by Yavari et al., (2017). No significant change in respiration rate in group II animals might be due to decreased dose used for modified IVRA.
       
Oxygen saturation significantly (P < 0.05) decreased between 5 and 60 minutes interval in both group of animals. Significantly low peripheral oxygen saturation might be due to lateral recumbency as rumen pressed the lungs and diaphragm. Lateral recumbency also impairs respiration in cows leading to a moderate increase in arterial pCO₂ and a decrease in pO₂ (Yavari et al., 2017).
       
Systolic pressure significantly increased at 15, 20 and 30 minutes in group I animals. It might be due to high dose of lignocaine hydrochloride for standard IVRA technique. A significant increase in mean arterial pressure (MAP) was also noted after IVRA (Yavariet_al2017). No significant change in diastolic pressure was noted in both the groups at different time intervals. After removal of tourniquet, diastolic pressure was nearly normal in both group animals. There was no significant change in rectal temperature in both groups at different time intervals. These results were in accordance with the findings of Patel et al., (2005).
       
Sensory and motor block onset time and recovery time was measured by pin prick method. Needle pricks to the interdigital space as a common nociceptive test for foot desensitization after LA and before surgical interventions should be reconsidered (Hudson et al., 2008). There was no significant change in sensory block onset time, motor block onset time, sensory block recovery time and motor block recovery time in both group I and II animals (Table 2; Fig 5).
 

 

Modified IVRA technique was safer as compared to standard IVRA because low doses of local anesthetic are required in this technique. Tourniquet may be released at once without any local anesthetic toxicity symptoms.