The patient presented to the practice with dystocia, the owner reported she was becoming increasingly distressed and restless with a history of abdominal contractions for 1 hour without delivery of any kittens.
Signalment
Species: Feline
Breed: Oriental Short Hair
Age: 2 years old
Gender: Female (entire/pregnant)
Weight: 3.6 kg
Patient examination
On arrival the patient was triaged and monitored by a registered veterinary nurse (RVN) until the veterinary surgeon (VS) examined her. The RVN noted a heart rate of 138 bpm (110–180) with strong synergistic pulses, and a respiratory rate of 38 bpm (20–40) with clear chest sounds. A rectal temperature of 37.8°C (38.3–38.8) with pink mucous membranes (MM) and capillary refill time (CRT) under 2 seconds were noted. Non-invasive blood pressure reading using an oscillometric device was obtained with a reading of 117/48 (71) (115–180 systolic). The patient was in sternal recumbence and was quiet and responsive. The Colorado State University feline pain score (Hellyer et al, 2006) was used as a tool for pain assessment with a result of 3 due to the patient tucking in her feet close to her body and some reaction to examination around her vulva. A result of 3 can indicate mild discomfort, a score of 5 or above would have indicated the need for pain relief. The VS performed a digital vaginal examination and diagnosed obstructive dystocia and was unable to correct the position of the kitten. The VS decided to perform an emergency Caesarean.
Intravenous
An intravenous catheter was placed into the patient's cephalic vein and fluid therapy was started with Hartmann's at 2 mls/kg/hour, increasing to 5 ml/kg/hour during surgery. A single dose of 0.02 mg/kg buprenorphine (Vetergesic, Ceva) was administered intravenously to the queen after the kittens had been removed during surgery.
Case discussion
Triage
Triage aims to review each body system quickly to highlight immediate issues which may require prompt treatment (Polton and Branscombe, 2008). The veterinary nurse can be a vital team member when it comes to initial assessment and monitoring of the patient (Howie, 2016). The patient was taken into the clinical preparation room on arrival to the practice. The RVN performed the initial examination while waiting for the VS to be available.
Respiratory assessment
At first a visual examination was performed assessing for signs of distress and dyspnoea. Body positioning was also noted for pain score purposes. The RVN first assessed respiratory effort and rate. There was no evidence of any increased effort, such as open mouth breathing, abducted elbows or exaggerated thoracic wall movement (Howie, 2016). No abnormal respiratory sounds were heard on chest auscultation. Respiratory rate was noted at 38 bpm which can be viewed as increased or within a normal range. Scherk (2013) suggested a normal range of 24–36 bpm, however, Howie (2016) suggested an increased respiratory rate would be above 40 bpm. As there was no other indication of respiratory issues, it was concluded the probable cause of this rate was possible stress from travel to the practice and possible pain due to the patient's presenting problem.
Examination of MM and CRT was made to assess oxygenation levels and circulation. Cyanosed membranes would have indicated reduced oxygenation and treatment would be required immediately. As the MM were pink and there were no other signs of dyspnoea, such as increased respiratory rate or effort, oxygen therapy was not provided as it was felt that it was not indicated, however, multiple authors (Traas, 2008; Smith, 2012; Davidson, 2010; Aarnes and Bednarski, 2015) have commented on fetal hypoxia increasing fetal death, therefore, providing oxygen supplementation may have been beneficial in this situation. Further assessment of oxygenation levels could have been performed using pulse oximetry (POX) (Hibbert, 2013). This method uses infrared light to assess oxygen bound to haemoglobin within the blood (Angell and Seymour, 2015), which could also be described as the oxygen available to be transferred. Although the pulse oximeter is an important piece of equipment, the first choice in assessment of gas exchange is arterial blood gas analysis (ABGA) which measures partial pressure of oxygen (PO2) and partial pressure of carbon dioxide (PCO2) from an arterial blood sample (Waddell and King, 2018). ABGA measures the pressure which is being used for the oxygen to be transferred to the tissues and the amount of carbon dioxide the patient is eliminating, giving an accurate assessment of how the patient is ventilating (Angell and Seymour, 2015).
Obtaining arterial samples need to be planned before-hand. Blood analysis to diagnose coagulopathies should be performed and must be normal before arterial puncture can be carried out (Roberts, 2016). Advanced skills compared with venous sampling are needed and can be challenging in smaller animals such as cats (Adamantos, 2018). Ischaemia, vascular spasm and arterial occlusion have been reported in cats after arterial catheter placement therefore a recommendation to remove the catheter after 6 hours has been suggested (Roberts, 2016). Placement for prolonged periods of time has been linked to catheter complications which resulted in a suggestion to remove the catheter once it use was not longer needed (Mooshian et al, 2019). POX and ABGA were not performed in the patient due to equipment availability. They may have been beneficial in this patient to accurately assess the patient's oxygenation status before the procedure, however, time constraints waiting for blood results for coagulopathies and time taken to place a catheter could have had a negative effect on the queen and neonates.
Cardiovascular assessment
A reduction in cardiac output will result in hypoperfusion of tissues, depriving them of oxygen and nutrients, leading to body system failure (Howie, 2016). The chest was auscultated to obtain a heart rate and the femoral pulse was palpated at the same time to assess quality and synchronicity with the heart. MM colour was noted as pink with a CRT of under 2 seconds. A rectal temperature was taken, reading 37.8°C, and systolic blood pressure reading of 117 mmHg obtained by an oscillometric device. As discussed above, MM and CRT were examined to assess circulation. In a hypoperfused patient, MM would be pale with a prolonged CRT (Donnelly and Lewis, 2016). Howie (2016) and Donnelly and Lewis (2016) supported obtaining a heart rate and assessing pulse quality and synchronicity at the same time, and use of blood pressure monitoring. Donnelly and Lewis (2016) stressed the importance of using a peripheral pulse rather than femoral pulse as absence of a peripheral pulse can indicate a blood pressure below 80 mmHg systolic. The RVN concluded the slightly lower rectal temperature was due to parturition, supported by Little (2013). The reduction in temperature is likely due to decline in progesterone as it has been suggested this hormone is thermogenic (Forsberg, 2010).
Using the readings of blood pressure and heart rate a shock index (SI) could have been calculated (Donnelly and Lewis, 2016). A SI is a value which can indicate the severity of shock the patient is experiencing, which could help prompt veterinary staff to act accordingly (Porter et al, 2013). This is calculated by heart rate divided by systolic blood pressure. In canine patients it has been suggested to have some clinical benefit, one study proving the SI increases in shock patients compared with healthy and emergency patients not in shock (Porter et al, 2013). Kenton (2017) conducted a pilot study investigating SI in feline emergency cases, and concluded that there was some evidence to support its use in practice. The SI was, however, suggested to be exacerbated in cats, as feline patients can be brady- or tachycardic during shock, which increases the SI ratio, implying when using SI in cats the treatment plan should not be based solely on the SI result. The author could not find evidence in relation to blood pressure monitoring in cats in dystocia. Authors writing regarding cardiac disease (Erling and Mazzaferro, 2008; West and Humm, 2015) commented on oscillometric devices underestimating blood pressure in hypotensive states, concluding that the Doppler method is preferable, however, the Doppler method would involve increased handling of the patient, which could affect stress levels, leading to an inaccurate result. The oscillometric method was therefore of more benefit for this patient, as increased stress could have affected the status of the patient and fetuses. By combining vital signs from the cardiovascular and respiratory assessment a treatment plan can be made, such as a fluid therapy plan.
Fluid therapy
The patient was initially placed on 2 ml/kg/hour of Hartmann's solution (Vetivex 11, Dechra). The rate was decided by the VS due to the queen being haemodynamically stable, showing no sign of shock and delivered using a fluid pump. Fluid administration was monitored every 30 minutes. Hourly checks were performed and included assessment of intravenous catheter site (checking for swelling and placement), chest auscultation to check for fluid sounds (such as crackles), heart and respiratory rate check and vital signs. Thirty minutes after this check the rate was checked again. Administration of fluids are often required for stabilisation before surgery, focusing on the treatment of shock, dehydration and electrolyte imbalances with the use of crystalloid fluids (Traas, 2008). This approach also helps with cardiac output prior to and during surgery (Fantoni and Shih, 2017), which could be compromised due to administration for anaesthetic drugs such as isoflurane. As discussed previously, maintaining cardiac output will be beneficial to the patient and fetuses, which is further supported by Traas (2008) who commented that crystalloid therapy will support blood pressure and uterine perfusion. Electrolyte abnormalities increase the risk of hypotension, arrhythmias and inadequate cardiac output (Fantoni and Shih, 2017). The VS decided not to perform electrolyte tests due to time constraints, retrospectively this could have made the anaesthetic safer for the patient.
Authors Orpet and Welsh (2011) support maintenance fluid rate of 2 ml/kg/hour. Auckburally (2016) has commented that this rate tends to underestimate maintenance needs in cats, therefore, a rate of 2–3 mls/kg/hour should be used instead. Another calculation suggests maintenance rate should be calculated with the formula: (30 X bodyweight) +70 = mls/day (Byers, 2017). This calculation would result in higher rates for smaller patients. The 2013 AAHA/AAFP Fluid therapy guidelines for dogs and cats also support a starting rate of 3 ml/kg/hour for cats (Davis et al, 2013). Zlicar (2017) discussed the importance of monitoring fluid therapy in human medicine and stated that incorrect administration leads to complications, extended hospital stays and increased cost. This could also be applied to veterinary practice as similar complications, such as volume overload, would involve further treatment for the veterinary patient. Moore (2007) supported the same checks that were carried out and adds that the catheter site should be checked for pain, this was not intentionally assessed, however, it would have been picked up on when performing the checks around the catheter site. Moore (2007) does not state the frequency of checks.
Pain monitoring and control
It has been suggested that a pregnant animal's pain tolerance is increased due to levels of pregnanolone (an endogenous neurosteroid) or endogenous endorphins (Aarnes and Bednarski, 2015). Discomfort in the patient should be a monitored and controlled (Davidson, 2010). It is difficult to create a pain control programme for the pregnant and Caesarean section patients as there is limited information regarding the safety of medications during pregnancy and lactation (Traas, 2008). The patient was given a single dose of buprenorphine 0.02 mg/kg (Vetergesic, Ceva) administered intravenously during surgery after the fetuses were removed. The Colorado State University feline pain score was used 30 minutes after recovery to assess the patient's pain. This score was developed specifically for veterinary patients, has few time constraints and is relatively easy to use (Thornley, 2015).
The use of opioids in lactating animals is supported by multiple authors (Traas, 2008; Davidson, 2010; Little, 2013). The total dose of opioid in milk and effects on the neonates is minimal (Traas, 2008). With this in mind the nurse could plan the timing of feedings to coincide with minimal concentrations of the drug. Opioids could however, cause sedation and depression in the nursing queen (Claude and Meyer, 2016), therefore non-steroidal anti-inflammatory drugs (NSAIDs) may have an advantage over opioids. NSAIDs are used commonly for postoperative analgesia in veterinary patients however their use in Caesarean sections should be approached with caution, with main concern focusing on transfer to the neonate via milk (Escobar and Kolster, 2016). Concern for the neonate is due to their immature renal and hepatic function (Davidson, 2010). It has been suggested that NSAIDs should not be used in Caesarean section patients (Davidson, 2010), however, a study focusing on carprofen, administered to bitches twice daily for 4 days, concluded that the drug was minimally detectable in expressed milk, while meloxicam had not been studied (Escobar and Kolster, 2016). Due to risks involving the offspring, it has been recommended that NSAIDs be administered once to the queen (Claude and Meyer, 2016).
Veterinary nurses play an important role in the use of holistic care plans and alternative treatments (Caldwell, 2013). Cold therapy is able to be used in postoperative patients in an attempt to reduce inflammation (Cantwell, 2007). Application of an ice pack or ice wrapped inside a damp towel to the wound after surgery slows down the metabolic rate of the tissues and histamine release, which slows down tissue damage (Corti, 2014). Traas (2008) supported the use of this treatment for postoperative Caesarean sections in veterinary patients. Both Caldwell (2013) and Corti (2014) suggest applying the cold compress four times a day for 10–15 minutes. Using cold therapy in humans has been shown to reduce narcotic use and reduce pain score results (Cort, 2014). Care should be taken if implementing this method to ensure kittens are not close to the cold compress, and it should be scheduled between feeding times. During the first week after birth, kittens do not have adequate subcutaneous fat, therefore rely on the queen's body heat to maintain their own body temperature (Casal, 2010). This method was not used in this patient but could be used in similar cases presenting in the future.
Another method of pain control which could be used is laser therapy. Therapeutic lasers use a light source which stimulates photochemical reactions within the cells, which has been shown to reduce pain, inflammation and oedema (Cantwell, 2010). The use of laser therapy on postoperative incisions is indicated for treatment of pain and reduces wound healing time (Pryor and Mills, 2015). The use of laser therapy would require a trained nurse to carry out the treatment and purchase of expensive equipment, which may make it difficult to integrate into general practice (Pryor and Mills, 2015). As the practice did not have the required training or equipment that was needed, laser therapy was not able to be carried out.
Conclusion and recommendations for future practice
The RVN must consider a number of factors when presented with a patient in dystocia. They must be confident to assess the patient's cardiovascular and respiratory status and identify immediate risks and dangers for their patient and initiate steps to prevent deterioration. Oxygen should be considered in all patients with dystocia to improve oxygenation to the fetuses, along with fluid therapy to support cardiac output and uterine perfusion. Use of a single dose of NSAIDs could be beneficial to the comfort of the queen and alternative pain therapies such as cold therapy could be easily used in all practices to improve pain control in these patients where conventional analgesia drugs should be used with caution. Finding evidence for this report was challenging and would suggest future research is required to concentrate on SI in cats and Caesarean section patients, especially for the feline species. The queen made a full recovery and was able to care for the neonates correctly resulting in 100% survival rate of the kittens.
KEY POINTS
- Providing oxygen to the queen decreases the risk of fetal hypoxia.
- If the queen is kept calm, a Doppler should be used to assess blood pressure as oscillometric devices can underestimate readings during hypotensive states.
- For fluid therapy in feline patients, a rate of 3 ml/kg/hour should be used for maintenance calculations.
- Administration of opioids after feeding the neonates will ensure the queen has appropriate analgesia while keeping drug concentration in the milk to a minimum.
- Non-pharmaceutical analgesia, such as cold therapy and laser therapy, should be considered in the lactating queen as alternative pain therapies.