The effects of a lung recruitment manoeuvre before extubation on pulmonary function after coronary artery bypass surgery

Nel, Stephanus Gerhardus (2013-12)

Thesis (MScPhysio)--Stellenbosch University, 2013.

Thesis

ENGLISH ABSTRACT: Aim: The aim of this study is to determine if the addition of a pre-extubation recruitment manoeuvre to standard care is safe and will improve lung compliance and subsequent PaO2/FiO2 (PF ratio) after extubation in postoperative coronary artery bypass graft surgery patients. Design: Prospective, triple blind, randomised, controlled trial. Method: This study was conducted in a private hospital in the Northern suburbs of Cape Town, South Africa. All patients admitted between 03/10/2010 and 22/11/2011, for uncomplicated elective coronary artery bypass graft (CABG) surgery were eligible for inclusion into the study. Patients were randomly allocated into either the intervention group or the control group. The intervention group received a gradual build-up lung recruitment manoeuvre (RM). The primary outcome was PaO2/FiO2 (PF ratio). The secondary outcomes were safety and static lung compliance. ICU length of stay (LOS) and hospital LOS were also recorded. The pre-RM hemodynamic stability of the patient was checked before the intervention and repeated at 5 minutes after the intervention by the nursing sister. Data to calculate static lung compliance was captured at the same time. Criteria for safety and discontinuation of the RM were monitored during the intervention by the principle investigator only. Results: Of the 69 patients eligible for the study 47 were randomly allocated into the intervention group (n=22) and control group (n=25) respectively. Groups were the same at baseline with regards to sex, pulmonary risk, sedation and surgical procedures. The RM could be completed in all patients. The prior defined criteria for discontinuation of the RM were not reached in any of the patients. No adverse effects were noted. The PaO2/FiO2 (PF ratio) decreased significantly in both groups from pre-surgery measurements compared to when measured before the RM (p<0.001). There was a tendency noted for the intervention group to return to pre-surgery measurements of PF ratio within 12 hours after extubation when compared to the control group. There was no significant difference between the groups from extubation to 24 hours (p = 0.6). The static compliance improved at 5 minutes following the RM (p<0.001) and remained improved until extubation (p<0.001) for the intervention group. No difference was noted in the static compliance of the control group over the same time period. The mean hospital length of stay for the intervention group was 8.61 (95% confidence interval 7.26 to 9.96 days) and 10.08 (95% confidence interval 8.52 – 11.63 days) for the control group. Conclusion: A gradual recruitment manoeuvre at 30cmH2O 30minutes before extubation significantly improved static lung compliance within 5 minutes with no adverse hemodynamic side effects. There was noted maintained improved PF ratio at extubation or immediately afterwards for the intervention group and no difference in the PF ratio between the intervention group and control group.

AFRIKAANSE OPSOMMING: Doel: Die doel van hierdie studie is om te bepaal of die toevoeging van ’n pre-ekstubasie herwinningstegniek tot standaard sorg veilig is, en of dit longvervormbaarheid en gevolglike PaO2/FiO2 (PF-verhouding) na ekstubasie in post-operatiewe kroonaaromleidingchirurgiepasiënte sal verbeter. Ontwerp: Prospektiewe, trippel-blinde, ewekansige, gekontroleerde proefneming. Metode: Hierdie studie is uitgevoer in ’n privaat hospitaal in die noordelike voorstede van Kaapstad, Suid-Afrika. Alle pasiënte wat tussen 03/10/2010 en 22/11/2011 gehospitaliseer is vir ongekompliseerde elektiewe kroonaaromleidingchirurgie, kon in aanmerking kom vir die studie. Pasiënte is op ewekansige wyse ingedeel in die intervensie- en kontrolegroepe. ’n Geleidelike-opbou-van-druk-longherwinningstegniek (HT) is op die intervensiegroep toegepas. Die primêre uitkoms was die PaO2 /FiO2 (PF-verhouding). Die sekondêre uitkoms was veiligheid en statiese longvervormbaarheid. ISE-verblyf en hospitaalverblyf is ook genoteer. Die navorsingsassistent het data van bestaande eenheiddokumentasie geneem. Die pre-HT-hemodinamiese stabiliteit van die pasiënte is gemonitor voor en weer 5 minute na die intervensie. Inligting om die statiese longvervormbaarheid te bereken is terselfdertyd genoteer. Kriteria vir veiligheid en vir die staking van die HT is gemonitor tydens uitvoering deur die primêre ondersoeker en die verpleegkundige. Resultate: Van die 69 pasiënte wat in aanmerking kon kom vir die studie is 47 op ewekansige wyse ingedeel in die intervensiegroep (n=22) en die kontrolegroep (n=25). Die groepe was dieselfde by die basislyn. Die herwinningstegniek kon volledig op alle pasiënte uitgevoer word. Die vooraf gedefinieerde kriteria vir staking van die HT is met geen pasiënte bereik nie. Geen nadelige uitwerking is genoteer nie. Die PaO2 /FiO2 (PF-verhouding) het beduidend verminder in beide groepe van pre-operatiewe metings in vergelyking met meting voor die HT (p<0.001). ‘n Neiging is genoteer dat die intervensiegroep binne 12 uur na ekstubasie tot pre-chirurgie PF-metings teruggekeer het. Daar was geen merkbare verskil tussen die groepe vanaf ekstubasie tot 24 uur (p=0.6) nie. Die statiese vervormbaarheid het verbeter teen 5 minute na HT (p<0.001) en het verbeter gebly tot ekstubasie (p<0.001) vir die intervensiegroep. Daar was geen verskil in die statiese vervormbaarheid van die kontrolegroep nie. Die gemiddelde hospitaalverblyf vir die intervensiegroep was 8.61 (95% betroubaarheidsinterval 7.26 tot 9.96 dae) en 10.08 (95% betroubaarheidsinterval 8.52 – 11.63 dae) vir die kontrolegroep. Gevolgtrekking: ’n Geleidelike herwinningstegniek teen 30cmH2O 30 minute voor ekstubasie het statiese longvervormbaarheid beduidend verbeter binne 5 minute, met geen nadelige hemodinamiese newe-effekte nie. Daar was geen verskil in die oksigenasie-indeks tussen die intervensie- en kontrolegroep na ekstubasie nie.

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