Short-term outcome of adrenalectomy in dogs with adrenal gland tumours that did not receive pre-operative medical management

OBJECTIVE

Review medical records of dogs that underwent adrenalectomy without pre-operative medical management, to examine the peri-operative morbidity and mortality.

DESIGN

Case series of 65 dogs.

METHODS

Medical records were reviewed. Features recorded included the histologic diagnosis, intra-operative hypertension or tachycardia, requirement for cavotomy, administration of intra- and post-operative corticosteroids, performance of additional surgery and the occurrence of peri-operative complications. Dogs requiring emergency surgery were excluded.

RESULTS

Of the 65 dogs, 49 had adrenocortical tumours (11 bilateral), 13 had pheochromocytomas (one bilateral) and three dogs had tumours in both adrenal glands of a different tumour type. Five dogs had caudal vena cava invasion and 33 had additional procedures performed at the same time. Mortality occurred in 1/65 dogs (1.5%; 95% CI 0.03%-8.2%), major complications were identified in 1/65 dogs (1.5%; 95% CI 0.03%-8.2%) and minor complications occurred in 10/53 dogs (15%; 95% CI 8.6%-26%).

CONCLUSION

Based on the limited peri-operative complications and low mortality in this pre-operatively untreated cohort, and based on critique of the available literature, the added value afforded by pre-operative treatment is questioned. With appropriate management, adrenal tumours can be removed with few peri-operative complications and low mortality.

Monitoring of tidal ventilation by electrical impedance tomography in anaesthetised horses

BACKGROUND

Electrical impedance tomography (EIT) is a method to measure regional impedance changes within the thorax. The total tidal impedance variation has been used to measure changes in tidal volumes in pigs, dogs and men.

OBJECTIVES

To assess the ability of EIT to quantify changes in tidal volume in anaesthetised mechanically ventilated horses.

STUDY DESIGN

In vivo experimental study.

METHODS

Six horses (mean ± s.d.: age 11.5 ± 7.5 years and body weight 491 ± 40 kg) were anaesthetised using isoflurane in oxygen. The lungs were mechanically ventilated using a volume-controlled mode. With an end-tidal carbon dioxide tension in the physiological range, and a set tidal volume (VT_vent ) of 11-16 mL/kg (baseline volume), EIT data and VT measured by conventional spirometry were collected over 1 min. Thereafter, VT_vent was changed in 1 L steps until reaching 10 L. After, VT_vent was reduced to 1 L below the baseline volume and then further reduced in 1 L steps until 4 L. On each VT step data were recorded for 1 min after allowing 1 min of stabilisation. Impedance changes within the predefined two lung regions of interest (EIT_ROI ) and the whole image (EIT_thorax ) were calculated. Linear regression analysis was used to assess the relationship between spirometry data and EIT_ROI and EIT_thorax for individual horses and pooled data.

RESULTS

Both EIT_ROI and EIT_thorax significantly predicted spirometry data for individual horses with R² ranging from 0.937 to 0.999 and from 0.954 to 0.997 respectively. This was similar for pooled data from all six horses with EIT_ROI (R² = 0.799; P<0.001) and EIT_thorax (R² = 0.841; P<0.001).

MAIN LIMITATIONS

The method was only tested in healthy mechanically ventilated horses.

CONCLUSIONS

The EIT can be used to quantify changes in tidal volume.