Pathway to postgraduate studies

Since completing her undergraduate degree in 1999 in Glasgow, Scotland, Michelle always wanted to continue to postgraduate studies. Then 10 years went by!! She now works in research so it’s a perfect opportunity to finally accomplish a personal goal while extending her academic and professional training.

Current work

'An observational study of nasal high flow therapy in intensive care practice: Predictors of success and failure'

Nasal High Flow (NHF) is a new form of high flow oxygen therapy, which delivers heated and humidified oxygen by nasal cannula. Preliminary evidence suggests that NHF may have some clinical benefits over high flow face mask oxygen therapy, however little evidence exists to support its application in specific patient populations. This project has two objectives. Firstly, to describe the use of NHF in a Cardiothoracic and Vascular Intensive Care Unit (CVICU) and High Dependency Unit (HDU). Secondly, to establish when NHF is associated with successful therapy outcomes and importantly when NHF is likely to be insufficient to meet the patient’s ventilatory requirements. In so doing, establish whether criteria can be identified to predict when NHF is likely to be successful and when it is likely to fail. Over a six month recruitment period, all patients who received NHF in the CVICU HDU were enrolled. Chart review was conducted immediately prior to NHF, then at 1 hour and 48 hours post commencement. Therapy outcome at 48 hours was determined by identifying which patients required an escalation in respiratory support compared with those who did not. Clinical variables during the 48 hour study period were also evaluated and the most deranged values while on NHF described. Preliminary results indicate that one hundred and twenty patients received NHF during the study period. Patients ranged from 24 to 84 years of age (median 65) and were predominantly male (69%) and New Zealand European (67%). The majority of patients were post op surgical, following either; coronary artery bypass grafting (29%); valve surgery (19%); thoracic surgery (12%) or; vascular surgery (13%). The most frequently cited reasons for commencing NHF were low PaO2 (68%) and/or low SpO2 (60%) with the mean estimated PaO2:FiO2 ratio being 190 (SD 56) immediately prior to commencing NHF. Nasal High Flow was considered to have failed for 26 patients (22%), requiring escalation to either; noninvasive continuous positive airway pressure via mask (n= 14); bilevel ventilation via mask (n= 7) or; invasive ventilation via endotracheal tube (n= 5). For 94 patients (78%) NHF was considered to be successful. Of the variables assessed in the preliminary analysis, mean arterial blood pressure was the only baseline variable which differed significantly between the ‘NHF success’ group vs the ‘NHF failure’ group (MAP 78.6, [SD 13.8] vs MAP 73.3 [SD 8.2] p = 0.017). PaO2:FiO2 ratio showed a trend at baseline between groups but this did not reach statistical significance (NHF Success = 195 [SD 58] vs NHF Failure = 177 [SD 49] p = 0.071). Further analysis to evaluate predictive criteria is currently underway.