Brenda Morrow

A comprehensive review of pediatric endotracheal suctioning: Effects, indications, and clinical practice*

Objective: To provide a comprehensive, evidence-based review of pediatric endotracheal suctioning: effects, indications, and clinical practice. Methods: PubMed, Cumulative Index of Nursing and Allied Health Literature, and PEDro (Physiotherapy Evidence Database) electronic databases were searched for English language articles, published between 1962 and June 2007. Owing to the paucity of objective pediatric data, all reports dealing with this topic were examined, including adult and neonatal studies. Results: One hundred eighteen references were included in the final review. Despite the widespread use of endotracheal suctioning, very little high-level evidence dealing with pediatric endotracheal suctioning exists. Studies of mechanically ventilated neonatal, pediatric, and adult patients have shown that suctioning causes a range of potentially serious complications. Current practice guidelines are not based on evidence from controlled clinical trials. There is no clear evidence that endotracheal suctioning improves respiratory mechanics, with most studies pointing to the detrimental effect it has on lung mechanics. Suctioning should be performed when obstructive secretions are present rather than routinely. There is no clear evidence for the superiority of closed- or open-system suctioning, nor is there clear evidence for appropriate vacuum pressures and suction catheter size. Sterility does not seem to be necessary when suctioning. Preoxygenation has short-term benefits, but the longer-term impact is unknown. Routine saline instillation before suctioning should not be performed. Recruitment maneuvers performed after suctioning have not been shown to be useful as standard practice. Conclusions: Endotracheal suctioning is a procedure used regularly in the pediatric intensive care unit. Despite this, good evidence supporting its practice is limited. Further, controlled clinical studies are needed to develop evidence-based protocols for endotracheal suctioning of infants and children, and to examine the impact of different suctioning techniques on the duration of ventilatory support, incidence of nosocomial infection, and length of pediatric intensive care unit and hospital stay.

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.

Pneumocystis Pneumonia in South African Children With and Without Human Immunodeficiency Virus Infection in the Era of Highly Active Antiretroviral Therapy

Background: Pneumocystis pneumonia (PCP) is a major cause of hospitalization and mortality in human immunodeficiency virus (HIV)-infected African children. Aim: The aim of this study was to investigate the incidence and outcome of PCP in South African children living in a high HIV-prevalence area in the context of a free, available antiretroviral therapy program. Methods: Sequential children hospitalized with hypoxic pneumonia were prospectively enrolled from November 2006 to August 2008. Sociodemographic, historical, clinical, and outcome data were collected. A nasopharyngeal aspirate and lower respiratory tract sample (induced sputum or bronchoalveolar lavage) were submitted for PCP immunofluorescence. Lower respiratory tract samples were also investigated for bacterial, mycobacterial, and viral pathogens. Results: A total of 202 children were enrolled; 124 (61.4%) were HIV-infected; 34 (16.8%) were HIV-exposed but uninfected and 44 (21.8%) were HIV-unexposed. Among HIV-exposed children, 70 (44.3%) had participated in the Prevention of Mother to Child Transmission program, but only 18.4% were taking trimethoprim-sulfamethoxazole prophylaxis. PCP occurred in 43 children (21.3%) of whom 33 (76.7%) were HIV-infected. The case fatality of children with PCP was higher than those without PCP (39.5% vs. 21.4%; relative risk, 1.85; 95% confidence interval, 1.15–2.97; P = 0.01). Conclusions: PCP is a common cause of hypoxic pneumonia and mortality in HIV-infected South African infants. Underuse of the Prevention of Mother to Child Transmission program and failure to institute trimethoprim-sulfamethoxazole prophylaxis in HIV-exposed children identified through the program are important obstacles to reducing PCP incidence.

Clinical course of hospitalised children infected with human metapneumovirus and respiratory syncytial virus

Aim:  To describe the clinical presentation and outcomes of hospitalised patients infected with human metapneumovirus (hMPV) and human respiratory syncytial virus (hRSV) in a tertiary hospital in Cape Town, South Africa.

An investigation into the prevalence and outcome of patients admitted to a pediatric intensive care unit with viral respiratory tract infections in Cape Town, South Africa.

Objectives: To describe the prevalence and outcome of patients admitted to a pediatric intensive care unit with viral respiratory tract infections. Design: Retrospective descriptive study. Setting: Pediatric intensive care unit in a tertiary pediatric hospital situated in Cape Town, South Africa. Patients: All children (n = 195; 20% pediatric intensive care unit admissions) with positive respiratory viral isolates between April 1 and December 31, 2009. Interventions: None. Measurements and Main Results: Demographic, clinical, laboratory, and outcome data were recorded from medical folders. Complete data were available for 175 patients (median age [interquartile range] 4.7 months [2.3–12.9 months]; 49% male). One hundred four (59.4%) patients had comorbid conditions; 30 (17%) were HIV-infected. Rhinovirus (n = 76 [39%]), respiratory syncytial virus (n = 54 [27.7%]), adenovirus (n = 30 [15.4%]), influenza A (n = 26 [13.3%]), parainfluenza (n = 23 [11.8%]), and human metapneumovirus (n = 12 [6.2%]) were most commonly isolated. Ninety-five infections (51.4%) were isolated >48 hrs after admission. Seasonal patterns were identified for respiratory syncytial virus, human metapneumovirus, and influenza A, whereas others occurred throughout the year. Twenty-five patients (14.3%) had more than one viral isolate. Presumed bacterial coinfection, which occurred in 68 (39%) patients (18 [26.5%] HIV-infected), was associated with significantly longer pediatric intensive care unit and hospital stays but not with mortality. Twenty patients died (11%, standardized mortality ratio 0.64). High Pediatric Index of Mortality scores, HIV exposure and infection, nosocomial infection, and influenza A infection were associated with mortality. Conclusions: Viral respiratory tract infection is common in this pediatric intensive care unit associated with significant morbidity and mortality, which may relate to the high burden of comorbidity and HIV.

Improved detection of Pneumocystis jirovecii in upper and lower respiratory tract specimens from children with suspected pneumocystis pneumonia using real-time PCR: a prospective study.

BackgroundPneumocystis pneumonia (PCP) is a major cause of hospitalization and mortality in HIV-infected African children. Microbiologic diagnosis relies predominantly on silver or immunofluorescent staining of a lower respiratory tract (LRT) specimens which are difficult to obtain in children. Diagnosis on upper respiratory tract (URT) specimens using PCR has been reported useful in adults, but data in children are limited. The main objectives of the study was (1) to compare the diagnostic yield of PCR with immunofluorescence (IF) and (2) to investigate the usefulness of upper compared to lower respiratory tract samples for diagnosing PCP in children.MethodsChildren hospitalised at an academic hospital with suspected PCP were prospectively enrolled. An upper respiratory sample (nasopharyngeal aspirate, NPA) and a lower respiratory sample (induced sputum, IS or bronchoalveolar lavage, BAL) were submitted for real-time PCR and direct IF for the detection of Pneumocystisjirovecii. A control group of children with viral lower respiratory tract infections were investigated with PCR for PCP.Results202 children (median age 3.3 [inter-quartile range, IQR 2.2 - 4.6] months) were enrolled. The overall detection rate by PCR was higher than by IF [180/349 (52%) vs. 26/349 (7%) respectively; p < 0.0001]. PCR detected more infections compared to IF in lower respiratory tract samples [93/166 (56%) vs. 22/166 (13%); p < 0.0001] and in NPAs [87/183 (48%) vs. 4/183 (2%); p < 0.0001]. Detection rates by PCR on upper (87/183; 48%) compared with lower respiratory tract samples (93/166; 56%) were similar (OR, 0.71; 95% CI, 0.46 - 1.11). Only 2/30 (6.6%) controls were PCR positive.ConclusionReal-time PCR is more sensitive than IF for the detection of P. jirovecii in children with PCP. NPA samples may be used for diagnostic purposes when PCR is utilised. Wider implementation of PCR on NPA samples is warranted for diagnosing PCP in children.

Prevalence and Outcome of Cytomegalovirus-associated Pneumonia in Relation to Human Immunodeficiency Virus Infection

Aim: To investigate the antemortem prevalence and outcome of cytomegalovirus (CMV)-associated pneumonia in African children. Methods: A total of 202 children (median age, 3.2 months; 124 human immunodeficiency virus [HIV]-infected, 62%; 87 severely malnourished, 43%) sequentially hospitalized for severe pneumonia were prospectively investigated. In addition to routine microbiologic investigations, respiratory tract secretions and blood were submitted for CMV culture and qualitative and quantitative CMV polymerase chain reaction. Results: CMV-associated pneumonia was common (28%, 47/169) and more prevalent in HIV-infected than uninfected children (36% vs. 15%; odds ratio [OR], 3.0; 95% confidence interval, 1.3–7.4). CMV-associated pneumonia was more common than Pneumocystis pneumonia (27%) and other viral-associated pneumonia (19%) in HIV-infected children. In-hospital mortality was 25% (51/202) with increased mortality in HIV-infected compared with uninfected children (43/124 [35%] vs. 8/76 [11%]; OR, 4.5; 1.9–11.8). Increased mortality occurred in HIV-infected children with CMV-associated pneumonia (OR, 2.5; 1.04–6.5) but this association was not evident after adjusting for CD4 <15% (adjusted OR, 1.78; 0.6–4.6). Conclusions: CMV-associated pneumonia is common and associated with a poor outcome in children with advanced HIV disease. Improved diagnostic testing and increased access to antiviral therapy might improve the outcome of HIV-infected children with CMV-associated pneumonia.

Investigation into the effect of closed-system suctioning on the frequency of pediatric ventilator-associated pneumonia in a developing country.

Objective: To investigate the effect of closed-system vs. open endotracheal suctioning on the frequency of ventilator-associated pneumonia and outcome in a pediatric intensive care unit in a developing country. Design: Prospective observational and nonrandomized controlled clinical study. Setting: A 20-bed pediatric intensive care unit in a tertiary pediatric hospital. Patients: Infants and children mechanically ventilated for >24 hrs. Intervention: Pediatric intensive care unit suctioning systems were alternated monthly. An 8-month interim analysis was planned with a priori efficacy and futility study termination boundaries set at p < .006 and p > .52, respectively. Measurements and Main Results: Demographic, clinical, and laboratory data were prospectively recorded. Ventilator-associated pneumonia was diagnosed using the Clinical Pulmonary Infection Score, and the results were confirmed retrospectively using Centers for Disease Control criteria. A total of 250 patients (median [interquartile range] age of 3.8 [1.2–15.0] months) in 263 pediatric intensive care unit admissions were included. Fifty-nine admissions developed ventilator-associated pneumonia, with a calculated rate of 45.1 infections per 1000 ventilated days. There was no difference in characteristics or outcome between patients on closed-system suctioning (n = 83) and those on open endotracheal suctioning (n = 180). The frequencies of ventilator-associated pneumonia for patients on closed-system suctioning and open endotracheal suctioning were 20.5% and 23.3%, respectively (p = .6), reaching the a priori set limit of futility. Patients who developed ventilator-associated pneumonia spent a median (interquartile range) of 22 (13–37) and 11 (8–16) days in the hospital and pediatric intensive care unit, respectively, compared to 14.5 (10–24) and 6 (4–8) days for those without ventilator-associated pneumonia (p < .001). A 22% proportion of patients who developed ventilator-associated pneumonia died compared to 11.3% of those without ventilator-associated pneumonia (p = .03). Risk factors for ventilator-associated pneumonia identified on multiple logistic regression were duration of mechanical ventilation, transport out of the pediatric intensive care unit, and blood transfusion. Conclusion: Closed-system suctioning did not affect the frequency of ventilator-associated pneumonia or patient outcome in this setting.

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.