Merle Futter

Effect of endotracheal suction on lung dynamics in mechanically-ventilated paediatric patients

Endotracheal suctioning is performed regularly in ventilated infants and children to remove obstructive secretions. The effect of suctioning on respiratory mechanics is not known. This study aimed to determine the immediate effect of endotracheal suctioning on dynamic lung compliance, tidal volume, and airway resistance in mechanically-ventilated paediatric patients by means of a prospective observational clinical study. Lung mechanics were recorded for five minutes before and five minutes after a standardised suctioning procedure in 78 patients intubated with endotracheal tubes < or = 4.0 mm internal diameter. Twenty-four patients with endotracheal tube leaks > or = 20% were excluded from analysis. There was a significant overall decrease in dynamic compliance (p < 0.001) and mechanical expired tidal volume (p = 0.03) following suctioning with no change in the percentage endotracheal tube leak (p = 0.41). The change in dynamic compliance was directly related to both endotracheal tube and catheter sizes. There was no significant change in expiratory or inspiratory airway resistance following suctioning (p > 0.05). Although the majority of patients (68.5%) experienced a drop in dynamic compliance following suctioning, dynamic compliance increased in 31.5% of patients after the procedure. This study demonstrates that endotracheal suctioning frequently causes an immediate drop in dynamic compliance and expired tidal volume in ventilated children with variable lung pathology, intubated with small endotracheal tubes, probably indicating loss of lung volume caused by the suctioning procedure. There is no evidence that suctioning reduces airway resistance.

Endotracheal suctioning: from principles to practice

ObjectiveThis paper aims to highlight the physical principles of pressure and flow dynamics underlying endotracheal suctioning, to demonstrate these on a simple illustrative model and to discuss the clinical implications of these principles for paediatric practice.DesignProspective in vitro study.SettingPaediatric intensive care unit of a tertiary, academic hospital.Measurements and main resultsThe peak pressure change (ΔP) obtained in a “bag-in-box” model was recorded during suctioning, using different combinations of endotracheal tube (ETT) and catheter sizes, different suction pressures and techniques. Suction was also performed on three different consistencies of gelatine, using a range of suction catheter sizes and vacuum pressures. The mass of gelatine suctioned per second was calculated. A large ΔP was measured when using neonatal-sized ETTs. There was a linear relationship (r=0,8, p<0.05) between ΔP and the ratio of external catheter area to area difference (internal ETT area−external catheter area). Significantly greater ΔP was measured when using a short versus long suction catheter (p<0.001) and when applying suction for longer duration (p<0,001) and with higher vacuum pressures (p<0.05). The amount of mucus suctioned in a given time was related to catheter size, suction pressure and mucus density.ConclusionApplied clinically, these results indicate that intrapulmonary pressure changes generated by the endotracheal suctioning of intubated neonates are likely to be considerable, possibly translating into loss of lung volume.

A recruitment manoeuvre performed after endotracheal suction does not increase dynamic compliance in ventilated paediatric patients: a randomised controlled trial

QUESTION Does a recruitment manoeuvre after suctioning have any immediate or short-term effect on ventilation and gas exchange in mechanically-ventilated paediatric patients? DESIGN Randomised controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis. PARTICIPANTS Forty-eight paediatric patients with heterogeneous lung pathology. Fourteen patients were subsequently excluded from analysis due to large leaks around the endotracheal tube. INTERVENTION The experimental group received a single standardised suctioning procedure followed five minutes later by a standardised recruitment manoeuvre. The control group received only the single suctioning procedure. OUTCOME MEASURES Measurements of ventilation (dynamic lung compliance, expiratory airway resistance, mechanical and spontaneous expired tidal volume, respiratory rate) and gas exchange (transcutaneous oxygen saturation) were recorded, on three occasions before and on two occasions after the recruitment manoeuvre, using a respiratory profile monitor. RESULTS There was no difference between the experimental and the control group in dynamic compliance, expired airway resistance, or oxygen saturation either immediately after the recruitment manoeuvre, or after 25 minutes. The experimental group decreased mechanical expired tidal volume by 0.3 ml/kg (95% CI 0.1 to 0.6), increased spontaneous expired tidal volume by 0.3 ml/kg (95% CI 0.0 to 0.6), and increased total respiratory rate by 3 bpm (95% CI 1 to 4) immediately after the recruitment manoeuvre compared with the control group, but these differences disappeared after 25 minutes. CONCLUSION There is insufficient evidence to support performing recruitment manoeuvres after suctioning infants and children.

Understanding of Genetic Inheritance among Xhosa-Speaking Caretakers of Children with Hemophilia

Hemophilia A and B are X-linked recessive inherited bleeding disorders that have a profound impact on the family of affected individuals. Education is vital to enable women to appreciate the implications of being a carrier and the implications for a prospective child. Prior research has shown that cultural, socio-economic and linguistic issues in South Africa are major barriers to communication for first-language Xhosa-speakers. This exploratory study aimed to investigate the basic knowledge of genetic inheritance among this cultural group in order to promote culturally-sensitive, effective genetic counseling. Ten in-depth interviews were conducted with Xhosa-speaking mothers or caregivers of boys with hemophilia. Results suggest that the participants had a very limited understanding of the clinical management, genetic consequences and cause of hemophilia. While treatment and care by health care service providers was fully accepted, several participants believed that traditional methods would provide them with more satisfactory explanations. These findings suggest that there is a critical need for socio-culturally tailored, language-specific education for families with hemophilia.

Prenatal diagnosis and termination of pregnancy: perspectives of South African parents of children with Down syndrome

This study aims to evaluate the attitudes of a group of South African parents with a preschool child with Down syndrome (DS) towards prenatal diagnosis (PND) and termination of a Down syndrome-affected pregnancy (TAP). This study employs a qualitative phenomenological approach with the use of semi-structured interviews. Twelve participants were recruited from two state sector hospitals in Cape Town, South Africa. Thematic analysis was used to interpret the data. The participants had a positive attitude towards PND and felt that it was every parents right to have the option. They considered a benefit of PND the fact that it allowed parents time to prepare for the arrival of a baby with DS. The induced miscarriage risk associated with invasive prenatal testing procedures caused major negative feelings. They were totally opposed to the termination of a Down syndrome-affected pregnancy due to their personal experience, moral, ethical or religious convictions. South African parents of preschool children with Down syndrome are comfortable with PND for Down syndrome; however, they do not support TAP. These findings will provide health care providers with further insight into the motivations behind the decisions their patients make.

A mobile colonoscopic unit for lynch syndrome: trends in surveillance uptake and patient experiences of screening in a developing country.

The Genetic and Endoscopic Surveillance Clinic is an annual outreach service offering accessible colonoscopic surveillance to known families with Lynch syndrome living in remote areas of the Western and Northern Cape Province of South Africa. Unfortunately attendance at this outreach clinic has been declining over several years and fewer than a quarter of participants, attending for surveillance, have been adherent with all their recommended screening appointments. Concerns exist for non-adherent individuals as screening can prevent colorectal cancer by removing the precancerous lesion or enabling the treatment of a malignancy at an early stage. This study explored the experience of surveillance from both the non-adherers’ and adherers’ perspectives and identified unique factors affecting attendance at the outreach clinic. Rates of compliance are calculated for 191 mutation-positive cases of Lynch syndrome, using strict attendance criteria, and compared to figures obtained from self-reported attendance. Non-compliance was under-reported and compliance was exaggerated when basing data on self-reported adherence to recommendations. Specific characteristics of the outreach clinic affecting compliance are identified and recommendations are made to facilitate improvements to the service. These improvements can result in increased compliance with screening regimens and ultimately reduce cancer-related mortality.