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The following case demonstrates the excellence of care that can be provided to trauma patients both on initial presentation to the emergency room, and for ongoing care in an intensive care unit. Milo, a seven-month-old intact male oriental short-hair, weighing 1.85kg was presented to his referring veterinarian shortly after falling from a balcony on the ninth floor of an apartment building. On initial physical examination he was found to be of quiet, yet alert mentation. He could stand with assistance and had a palpable, closed, fracture of the left distal limb. He was hypothermic (36.6°C) and tachycardic (HR = 200bpm). Thoracic auscultation was described as ‘crackly’. There was also evidence of head trauma, with an avulsed mandibular lip, and fractured left upper (deciduous) canine tooth.
Milo was treated with an unspecified amount of IV fluids, and 0.01mg/kg buprenorphine IM. Radiographs were performed of the thorax and pelvic limbs. These revealed a small volume pneumothorax, mild generalised interstitial pattern, and an oblique mid-diaphyseal fracture of the left tibia and greenstick fracture of the fibula.
Approximately 90 minutes after presentation, Milo’s mentation deteriorated, and he started open-mouth breathing. This prompted referral to SASH in North Ryde for further care. On arrival to SASH, Milo was semi-comatose, responsive only to painful stimuli. He had several markers of shock on physical examination, including hypothermia (36°C), severe sinus tachycardia (260bpm), weak femoral pulses, and very pale mucous membranes.
Altered mentation is also a sign of shock, however other causes such as traumatic brain injury, could not be ruled out at this time. He was tachypnoeic (RR 50bpm) with increased effort, and harsh lung sounds bilaterally, with crackles ventrally. A summary of Milo’s diagnostics included:
Thoracic point-of-care ultrasound (TPOCUS):
- glide sign present on both sides, indicating pneumothorax was not complete
- scant volume pleural effusion
- coalescing B-lines ventrally on each side, and dorsally on the right side
Abdominal POCUS:
- moderate volume peritoneal effusion
- urinary bladder visualised and was small
Venous blood gas:
- marked, mixed respiratory and metabolic acidosis: pH: 7.063 (ref range: 7.31 – 7.46), pCO2 61.3 mmHg (ref range: 26 – 36 mmHg), SBE: -12.8 mmol/L; ref range: -2 – 2 mmol/L)
- hyperlactataemia 8.4 mmol/L (ref range: 0 – 4 mmol/L)
- hyperglycaemia 9.4 mmol/L (ref range: 3.3 – 6.2)
- PCV/TS: 27/46
- Blood type: A
Based on a combination of physical examination and biochemical markers of shock, anaemia, and low total solids, Milo’s shock was classified as most likely hypovolaemic due to haemorrhage. Potential sources of blood loss included pulmonary contusions, haemothorax, and haemoperitoneum, although uroabdomen could not be excluded at this time as the cause of the peritoneal effusion. Differentials for the altered mentation included shock with or without traumatic brain injury, hypoxaemia, or pain. Patients in hypovolaemic shock require volume resuscitation. Blood transfusion is ideal in bleeding patients as it replaces like for like, but is not always possible, or necessary for a good outcome. In Milo’s case, there was no blood on hand for resuscitation. Instead, Milo was administered Hartmann’s solution 5mg/kg over 15min, Hypertonic saline 7% 3ml/kg over 15min, and Tranexamic acid 15mg/kg.
Hypertonic saline provides an added benefit of addressing any increase in intracranial pressure that might be present. Tranexamic acid is an antithrombolytic that slows down the dissolution of clots. Its use in cats is reported rarely in the literature, confined to case reports and retrospective studies (Wahldén et al, 2020; Kelly et al 2022) which provide records of doses and suggest it is safe, however efficacy is unknown.
Milo was also treated with ketamine 1mg/kg followed by a CRI for analgesia (2 – 4mcgkg/hr), actively warmed with a Bair Hugger, and provided oxygen supplementation via mask. Thoracocentesis was performed and yielded 6ml of air. A splint was placed on the left pelvic limb to provide stability to the fracture.
Following these interventions, there was a marked improvement in Milo’s mentation however he still appeared to be in shock. Repeat APOCUS revealed the urinary bladder to have increased in size from 1cm to 6cm diameter, with no subjective increase in the volume of peritoneal effusion. Oscillometric blood pressure was 74/47 (mean 56).
It was clear Milo needed more volume resuscitation, so a transfusion of 24ml fresh frozen plasma was administered, over three hours. Milo was moved to an oxygen cage in the ICU, and a fentanyl CRI was added. After the transfusion, venous blood gas was repeated and there was marked improvement in perfusion markers: pH: 7.283, pCO2 43.9 mmHg, SBE: -6.0 mmol/L, lactate 1.4 mmol/L. PCV/TS was 21/44. Milo was now of bright mentation, his body temperature had increased to 38°C and his pulse quality was ‘fair’. Doppler blood pressure was 90mmHg, however he was still tachycardic at 240bpm.
Despite the tachycardia, the decision was made to stop fluid resuscitation. Milo was started on IV fluids (Hartmann’s + 20mmol KCl/L) @ 5ml/hr. Over the subsequent days he became stronger and his breathing improved. By day two he had urinated several times in a litter tray and had resumed eating. His peritoneal effusion was described as ‘scant volume’, and creatinine was measured at 50 mmol/L (ref range: 53 – 141). These findings ruled out uroabdomen. On day three, Milo was weaned off O2 supplementation. His PCV/TS had rebounded a little, to 24/60.
On day four Milo underwent surgery to repair his tibial fracture. The gingival avulsion was left to heal by secondary intention, and the fractured tooth left in place in the hope it would soon be dislodged by the permanent tooth. Milo was discharged the following day.
Milo’s case demonstrates an approach to ‘low volume’ fluid resuscitation in patients with haemorrhage, the purpose of which is to improve perfusion, but not so much as to exacerbate bleeding. It is recommended in patients for whom ligation of bleeding is impossible (such as with pulmonary haemorrhage), pending surgical ligation of the bleeding vessels/tissue, or if the goal is to avoid surgery. It is a difficult line to tread and requires very close monitoring of the patient to determine success. Patients should be monitored closely in the first two hours following resuscitation. Those with ongoing haemorrhage will experience a deterioration in their perfusion parameters in line with the degree of shock. Rechecking effusion volumes on ultrasound, PCV/TS, and lactate can also help.
References:
Wahldén, L, Stanzani, G, Cutler, S, Barfield, D, Manson, KC, Wilson, HE & Thomas, EK 2023, ‘Evaluation of Therapeutic Use of Antifibrinolytics in Cats’, Journal of the American Animal Hospital Association, vol. 59, no. 4, pp. 177-183. https://doi.org/10.5326/JAAHA-MS-7349
Kelley M, Sinnott-Stutzman V, Whelan M. Retrospective analysis of the use of tranexamic acid in critically ill dogs and cats (2018 – 2019): 266 dogs and 28 cats. JVECC 2022;32:791–799.
Dr Erin Mooney BVSc DACVECC Grad Cert Ed Stud (Higher Education) FHEA
Emergency and critical care specialist
Small Animal Specialist Hospital (SASH)
Dr Erin Mooney graduated from the University of Sydney in 2007 with honours. She then undertook an internship in small animal medicine and surgery at a specialist hospital in Connecticut, USA.
Dr Mooney did her residency at Tufts University in Massachusetts, a world-leading centre for emergency and critical care and became a Diplomate of the American College of Veterinary Emergency and Critical Care in 2012.
Dr Mooney returned to Australia to practise as—at the time—one of very few emergency and critical care specialists nationwide.
She has worked at the Universities of Melbourne and Sydney, and currently works at SASH in North Ryde, as a member of the country’s biggest team of emergency and critical care specialists.
