THE USE OF HYPERINFLATION IN THE MANAGEMENT OF INTUBATED AND VENTILATED ADULT PATIENTS RECOMMENDATIONS Recommendation 1 on website Hyperinflation (Ventilator or manual) might be included in the management of intubated and adult on evidence of CR infiltrates; volume loss; ecessive secretions or decreased oygenation Weak recommendation Hyperinflation resulted in improvement in pulmonary compliance and secretion production in one randomized cross over design study ( et al ) when compared to a no intervention control. No adverse effects were recorded. The effect on LOS or TOV is not clear. Based on moderate quality evidence downgraded due to imprecision of data and sample. Recommendation 2 Ventilator hyperinflation (VHI) might be preferred method when compared to manual hyperinflation. When using MHI include PEEP valve and set at the ventilator level. Weak recommendation A greater improvement in pulmonary compliance when comparing VHI to MHI was observed in one randomized crossover design study (Savian et ) while there was no difference in the volume of wet weight sputum removed in two studies comparing VH to MHI ( ; Savian et ). No harm was reported with adherence to strict criteria, but effect on LOS and TOV has not been established Based on moderate quality evidence provided by two crossover design studies ( ; Savian et al ). The quality of the evidence is downgraded to moderate quality due to the imprecision of data. Recommendation 3 Rebreathing bag is the preferred choice of equipment when considering manual hyperinflation to remove secretions. Weak recommendation Rebreathing bag cleared more secretions when compared to a self inflating bag in one randomized crossover design study ( et al 2007). No difference was observed in the pulmonary compliance or oygenation. Although no harm was observed the effect of this outcome on LOS and TOV has not been established based on moderate quality evidence from one randomized crossover design study downgraded for imprecision of sample.
Review question: What is the safest (hemodynamic stability) and most effective technique and equipment used in hyperinflation of the lungs of intubated and to affect pulmonary mechanics (compliance; oygenation; removal of secretions)? Following a systematic review of the literature; critical appraisal of identified studies; the following conclusions were reached: SEARCH RESULTS Two systematic reviews and seven eperimental studies were included in this review Systematic Reviews Two systematic reviews evaluating the effect of the rebreathing bag (Brazier 2003) and the self inflating bag (Barker ) respectively, were included. Brazier (2003) evaluated the evidence for the safety (haemodynamic variables) and effectiveness (lung compliance and oygenation) of the rebreathing bag to perform hyperinflation of the lungs in intubated adult. Seven databases were searched and the search was limited to eperimental studies published from January 1983 to January 2003. From 58 studies identified, five studies were included in the review. Due to heterogeneity data could not be pooled. (Refer to table 1 for summary) Barker et al () evaluated the clinical value of MHI using self inflating rebreathing bags. Only one data base was searched (Medline) for studies published between 1968 and 1995. Eleven eperimental studies were identified resulting in the data from 136 intubated and. Pulmonary compliance and oygenation were the two outcomes measured. Eperimental studies One eperimental study evaluated the effect of MHI in septic shock (Jellema ); Three studies specifically investigated the physiological effect ( et al ; Paratz 2002; Paratz ); While three studies compared equipment (Berney 2002: Savian ; 2007). The majority of the studies used a randomized crossover design and Pedro scores varied between 4 8/11. The biggest concern being the lack of blinding. SUMMARY OF EVIDENCE Both reviews epressed concerns related to the standardization of the technique and equipment used to perform hyperinflation (refer to table 1 for a summary of reviews) Table 1 Summary of reviews Review AMSTAR Score included Barker et al Brazier et al 2003 3 7 RCT s with data from 136 4 5 RCT s with data from 225 Population Variety of intubated and including neonates and post CABG surgery Variety intubated including ALI and CABG surgery Intervention and comparison Self inflating manual resuscitation bags Rebreathing bag Outcome measured pulmonary compliance and oygenation Hemodynamics; lung compliance and oygenation Conclusion Variability in the application of the technique is cited as the reason for inconclusive results. Recommendations ito technique application for future studies are provided. Short term improvement in compliance and oygenation. Effect size unsure. Decrease in cardiac output observed.
MHI is indicated when There are signs of volume loss; unilateral infiltrates visible on CR ( et al ; et al 2007) Oygenation is affected with pao2:fio2 < 350 ( et al ; et al 2007) If clinically indicated (refer to above mentioned) MHI can be considered in presenting with septic shock; or on moderate doses of inotropes if adequately fluid loaded ( ; Jellema et al ) The outcomes measured in the eperimental studies are summarized in table 2. Table 2 Summary of outcomes measured in eperimental studies et al Jellema et al Savian et et al 2007 Internal validity (Pedro Score) Sampl e size Patient population 7 18 Intubated and with changes on CR and PaO2: FiO2 4 13 Pt with septic shock 6 20 Intubated and 5 16 Intubated and hemodynamically stable 5 7 Intubated and also septick shock with adequate fluid 5 14 Intubated and 8 20 chest -ray evidence of lung collapse and/or consolidation, and PaO2/FiO2 < 350 Intervention and comparison Sidelying compared to sidelying and MHI MHI compared measures over different time levels VHI compared to MHI MHI compared measures over different time levels MHI compared measures over different time levels VHI compared to MHI laerdal (self inflating resus bag compared to mapleson (rebreathing bags) Outcomes measured Compliance Wet weight sputum Oygenation Cardiovascular The optimal equipment will include (refer to table 3) a manometer in a circuit (Paratz 2002) a mier into the circuit and set FiO2 the same as ventilator. No detrimental effects have been noted; ( et al ; et al 2007); and decreases possibility of absorption atelectasis (Rothen et al 1995). A PEEP valve attached to circuit and set at the same level of PEEP currently dialed on the mechanical ventilator (Savian et )
Table 3 Summary of equipment used VHI MHI MHI PEEP FiO2 Manomete Flow meter Mapleson Laerdal r Not specified Same as ventilator 15 l/min et al Jellema et al Not specified Not specified Not specified Savian et et al 2007 Not specified Not specified 10 l/min 5cmH2O maintained in 100% 15 l/min circuit 5cmH2O maintained in 100% 15 l/min circuit PEEP at same level as 100% 15 l/min ventilator No Peep Same as ventilator 15 l/min The optimal tecnique will (refer to table 4) Manually hyperinflate to a PIP of AT LEAST 35 cmh2o ( ; ; et al ) but NOT MORE than 40cmH2O ( et al 2007; Savian et ) Use inverse I:E ratio of 2:1 when applying technique Table 4 Summary of technique used PIP I:E sets et al 40 cmh2o 2 sec hold ; E unobstructed 6 sets of 6 breaths Jellema et al Subjective feel Slow insp; insp hold and rapid release Not stated; investigated routine use 40 cm H20 Tidal breaths to 20 cmh2o 3 sec inspiration; 2 sec hold; rapid release 6 sets of 6 breaths each set followed by si tidal breaths 20 minutes total duration Not stated only that it was 1.5 sec inspiration 2 sec hold; rapid release 3 min total set 30 cm H2O 2 sec inspiration; 2 sec hold; rapid release 3 min total Savian et Not stated only that it was 2 sec inspiration; 2 sec hold; 1 sec epiration 8 breaths/min for 3 et al 2007 set minutes 40 cm H2O 2 sec hold ; E unobstructed 6 sets of 6 breaths total 20 min The following is a summary of the safety precautions adhered to by the included studies that resulted in limited hemodynamic effects described in table 5. The hemodynamic effects are temporary and none of the studies reported adverse effects. reported increase in norepinephrine levels (refer to table 5 for the hemodynamic variables measured). Check the cardiovascular stability ( ; ) o MAP > 75 mmhg and does not fluctuate more than 15 mmhg with position change o Heart rate is less than 130. o Arterial oygen saturation SaO2 is not less than 90 o No Cardiac arythmias present o Pt is hemodynamically stable as discussed with intensivist None of the following pathologies are present: ( et al ; et al 2007) o ARDS; Acute pulmonary oedema; Acute head injury; Acute bronchospasm; Subcutaneous emphysema; presence of inetrcostal catheter with a visible air leak Check the state of the pulmonary system ( et al ; et al 2007; Savian et ) o The peak inspiratory airway pressure is less than 40cmH20; o The patient is not with PEEP of more than 10cm H2O
Table 5 Summary of hemodynamic variables measured HR MAP DAP CI SVRI Adverse effects recorded et al No change One pt could not tolerate sidelying Jellema et al al 2002 al Savian et al et al 2007 position No change No change No change No change No significant hemodynamic changes No change No change No increase in inotropic support No change No change Increased from 0.03 (+-0.13) CI - 128. (+- 214) CI - 59.3 (+-7.1) to 0.034, -0.11 * 2667, 1064 * 66.8 (+-8.2) after 3 min of MHI * No change No change No change Mean dif -45.4(+- 1.5) CI -46.8, -44.0 Mapleson C appears to clear more secretions than the Laerdal circuit ( et al 2007) VHI appears to be safer (decruitment and increased PIP) and just as effective in secretion mobilization as MHI (Savian et al 06; ) Table 6 Summary of effect on pulmonary system Significant increase in norepinephrine levels (mean dif -2.8(+-1.3) CI - 4.1, -1.6. No change No change No adverse effects noted No adverse effects documented. All participants completed et al Jellema et al Savian et et al 2007 Pulmonary compliance MHI 8.5 CI 1.4-19.6 SL 0.2 CI-6.9 7.9 MHI mean improvement 51.5 (11.5%) CI (46.6 56.4) VHI 49.3 (9.8%) CI (45.7 52.9) Increased from 41.6 (+- 13.4) to (+-14.2) 50.7 Mean dif 5.5 SE 1.48 CI 1.1-9.94 Mean dif 1.8 CI ( 0.5 to 4.1) Tidal Volume Oygenation Wet weight sputum Adverse effects Mean TV increase from 499 ± 176 to 587 ± 82 * Mean dif 19.9 CI ( 0.6 to 40.4) Pa:O2 decreased form 251 (+- 77.6) to 246 (+-93.4) Mean dif - 41.8(+-73.7) CI -110.0, 26.36 no significant difference in improvement on PaO2/FIO2 between techniques Mean dif 14.2 CI ( 22.8 to 5.7) MHI 5.5 CI 2.6 8.5 SL 3.5 CI 2.4 4.6 mean dif in sputum production and 95% CI was 2.65 grams (range 1.79 3.54). MHI 1.31 g (+-0.81) and VHI 1.87 g (+-2) Mean dif 0.89 CI (0.80 to 1.15) PIP 72+- 17 cmh20 No difference in pulmonary artery pressure No adverse effects noted No adverse effects documented. All participants completed
QUALITY OF STUDIES One study specifically compared MHI to a no intervention control ( et al ) and reported a significant improvement in both compliance and wet sputum production with the addition of MHI. This evidence is downgraded to moderate quality due to imprecision of data and sample. One patient was withdrawn from study as he could not tolerate SL position. No adverse effects were recorded (hemodynamics). Two studies compared VHI to MHI ( ; Savian et ) and reported no difference in pulmonary sputum production. One study reported a significant improvement in pulmonary compliance with VHI (mean dif 5.5 CI 1.1-9.94). The quality of the evidence is downgraded to moderate quality due to the imprecision of data. No adverse effects were recorded in anyone of the studies. One study compared self inflating bag to a resuscitation bag ( et al 2007) and reported a significant increased sputum production with the self inflating bag (0.89 g CI 0.80 to 1.15). No difference in respiratory compliance; tidal volume; oygenation or CO2 removal. The quality of this evidence downgraded to moderate due to imprecision of sample. No adverse hemodynamics or pulmonary effects were recorded. Table 7 Quality of evidence of randomized cross over designs Eperimental et al al 2002 Savian et al et al 2007 Study design yes yes Risk of bias Washout selected Directness of evidence Heterog eneity Precision Intervention Publicati Data investigated investigated on Bias NA No (wide CI) No NA No NA NA No (mean dif 5.5 CI 1.1-9.94) (Mean dif 0.89 CI (0.80 to 1.15) No Table 8 Quality of evidence of observational studies Eperimental Jellema et al al 2002 al Concealed allocation Risk of bias Lost to follow up ITT Directness of evidence Intervention investigated No No No No (technique unspecified) investigated No (Septic Shock) Heterog eneity Publicati on Bias Data Precision N/A No No No N/A No No (16/required 29) No No (Septic shock) N/A (mean dif: -2.8 (+-1.3) CI -4.1, -1.6. No (7/required 15)