Table 1 Key findings from studies examining indices of nutritional status following liberation from mechanical ventilation

Nematy et al., 2006 [19] (England)

Prospective, observational study

To investigate gut hormone concentrations in patients during ICU stay and following LMV and relate them to appetite and energy intake measures.

Critically ill adults requiring MV and anticipated ICU LOS > 3 days

n = 16 ICU patients

n = 36 healthy controls

Energy intake:

Oral diet: Food records completed daily by nursing staff

EN/PN: calculated from flow sheets in the medical record

Healthy controls: 3-day food diary

Estimation of energy requirements to assess adequacy:

Compared energy intake of ICU patients to healthy control subjects

Factors affecting intake:

Appetite: VAS

Body composition:

ICU admission: weight, BMI, TSF, MAC

ICU discharge: weight, BMI, TSF, MAC

In comparison with healthy controls, following ICU discharge, patients consumed ~ 52% of energy and had significantly lower appetite scores, higher nausea, and earlier satiety.

Peterson et al., 2010 [20] (USA)

Prospective, observational study

To assess protein and energy adequacy and identify barriers to oral intake in ICU patients prescribed an oral diet exclusively during the first 7 days following extubation.

Critically ill adults requiring MV for > 24 h

n = 50

Energy and protein intake:

Modified multiple-pass 24-h recall conducted daily study duration

Estimation of energy and protein requirements to assess adequacy:

BMI < 30 kg/m²: 25 kcal/kg admission weight, 1.2 g protein/kg admission weight

BMI ≥ 30 kg/m²: 11 kcal/kg admission weight, 2 g protein/kg ideal weight (calculated using Hamwi equation)

Factors affecting intake:

Patients asked open-ended questions to identify barriers to intake

Body composition:

ICU admission: Weight, BMI, TSF, MAC

Global nutritional status assessment:

ICU admission: SGA

Over first 7 days post-extubation, mean calorie and protein intake never exceeded 55% (ranged from 34–55%) and 37% (ranged from 23–37%) of estimated requirements, respectively. Primary barriers to eating: poor appetite, nausea/vomiting, difficulty chewing/swallowing, and disliking the food.

Salisbury et al., 2010 [21] Click or tap here to enter text.(Scotland)

Pilot feasibility case study

To describe the role and issues raised around the implementation of using a GRA to deliver enhanced physiotherapy and nutrition rehabilitation for up to 7 weeks after critical illness.

Critically ill adult requiring MV for > 4 days (stroke, head injury and liver transplant patients excluded)

n = 1

Measures taken weekly for 7 weeks following ICU discharge

Energy and protein intake:

Food record charts (completion of food records was part of the enhanced nutrition care delivered by the GRA)

Estimation of requirements to assess adequacy:

Schofield and Elia equations

Factors affecting intake:

Appetite VAS

Body composition:

Weight, MAMC

Functional status assessment:

Rivermead Mobility Index, Timed-Up-and-Go, 10-meter walk test, hand-grip strength

Over 7 weeks post-ICU discharge; calorie intake as a percent of requirements ranged from 70 to 215% and protein intake 66–258%. (note: patient received nutrition via NGT or PEG during this period and fed to promote weight gain); improvements in functional measures and appetite observed between weeks 0 and 7; weight not reported.

Salisbury et al., 2010 [22] (Scotland)

2 studies:

1) Service evaluation of care

2) Pilot feasibility RCT

1) Determine the ward-based physiotherapy and nutrition services patients currently received following ICU discharge.

2) Determine whether use of a rehabilitation assistant to provide enhanced physiotherapy and nutrition rehabilitation is feasible.

Critically ill adults requiring MV for > 4 days (stroke, head injury and liver transplant patients excluded)

Study #2:

Intervention group (assigned a rehabilitation assistant): n = 8

Control group (standard care): n = 8

Measures taken weekly and 3 months following ICU discharge

Energy and protein intake:

Food record charts (completion of food records was part of the enhanced nutrition care delivered by the rehabilitation assistant)

Estimation of requirements to assess adequacy:

Schofield and Elia equations

Factors affecting intake:

Appetite VAS

Body composition:

Weight, MAMC

Functional status assessment:

Rivermead Mobility Index, Timed-Up-and-Go, 10-meter walk test, hand-grip strength

Patients in the control and intervention group consumed a weekly median 102% and 115% of estimated calorie requirements, respectively, and 63% and 77% of estimated protein requirements. At 3 months post-discharge, patients in the control and intervention groups were consuming a median 70% and 113% of estimated calorie requirements, respectively, and 69% and 90% of estimated protein requirements.

Merriweather et al., 2014 [23] (Scotland)

Qualitative: Grounded theory

To examine organizational issues and barriers influencing nutrition care during the post-ICU hospital stay.

Critically ill adults requiring MV for > 48 h

n = 17

Organizational factors influencing nutrition care were acquired through observation of usual care and semi-structured interviews

Three organizational factors influencing nutritional intake were identified: ward culture, system-centered delivery of care, disjointed discharge planning.

Walsh et al., 2015 [24] (Scotland)

Multicenter, randomized parallel group intervention trial

To determine the effect of increased physical activity and nutrition rehabilitation delivered during the post-ICU acute hospital stay via use of a rehabilitation assistant on mobility, quality of life and disability.

Critically ill adults requiring MV for > 48 h (TBI, intracerebral bleed, stroke, Guillain–Barre syndrome excluded)

Intervention group: n = 120

Control group: n = 120

Factors affecting intake:

ICU discharge, 3-, 6-, and 12-month follow-ups: Appetite VAS

Body composition:

3-month follow-up: Weight, BMI

Global nutritional status assessment:

3-month follow-up: SGA

Functional status assessment:

Weekly in hospital post-ICU discharge and 3-, 6-, and 12-month follow-up: Rivermead Mobility Index

3-month follow-up: Timed-Up-and-Go Weekly in hospital post-ICU discharge and 3-month follow-up: hand-grip strength

Nutrition intake data not reported. Patients in the intervention group reported higher satisfaction with eating and nutritional support.

Chapple et al., 2016 [25] (Australia)

Prospective observational study

To quantify the amount of energy and protein prescribed and delivered throughout hospitalization (ICU and ward) in critically ill patients with TBI.

Critically ill adults with TBI requiring ICU stay ≥ 48 h

n = 37

Energy and protein intake:

EN/PN: calculated daily from flow sheets in the medical record up to day 90 of hospitalization

Oral diets: weighed food records 3 days per week (2 weekdays, 1 weekend day) up to day 90 of hospitalization

Estimation of requirements to assess adequacy and cumulative deficit:

Energy and protein prescriptions assessed by the hospital dietitians as part of standard care were extrapolated from the charts

Barriers to intake:

Interruptions to nutrient provision documented from patient medical records

On the ward, patients receiving EN exclusively received 89% and 76% of energy and protein requirements, respectively; patients on oral diets exclusively consumed 75% and 74% of energy and protein requirements, respectively. Cumulative energy deficits accrued daily were significantly greater for patients on oral diet vs EN (~ 800 vs 450 kcal/d); daily protein deficits, while high, were not significantly different between those on an oral diet vs EN (40 vs 37 g protein/d).

Merriweather et al., 2016 [26] (Scotland)

Qualitative: Grounded theory

To explore factors influencing nutrition rehabilitation during hospitalization following ICU discharge and at 3 months following ICU discharge.

Critically ill adults requiring > 48 h MV

n = 17

Factors influencing nutrition care were acquired through researcher observation of usual care (1 h for 3 times weekly) and semi-structured interviews (weekly during patients stay on the ward and at 3 months post-ICU discharge)

“Inter-related system breakdowns during the nutritional recovery process” was the overarching category identified that influenced eating post-ICU. Major themes identified that influence nutritional recovery included: experiencing a dysfunctional body, experiencing socio-cultural changes in relation to eating, and encountering organizational nutritional care delivery failures.

Chapple et al., 2017 [27] (Australia)

Prospective observational study

To describe changes in anthropometrics and nutritional status in TBI patients between ICU admission and 3 months post-admission.

Critically ill adults with TBI requiring ICU stay ≥ 48 h

n = 37

Body composition:

Day 7 post-ICU admission, weekly thereafter until hospital discharge (up to 3 months post-admission): Weight, ultrasound assessment of quadriceps muscle layer thickness

Global nutritional status assessment:

Day 7 post-ICU admission, weekly thereafter until hospital discharge up to 3 months post-admission: SGA

Functional status assessment:

SF-36v2

Between hospital admission and discharge, mean weight loss was ~ 5%; at 3 months following ICU admission, weight loss persisted. The slope of quadriceps muscle layer thickness loss was steepest during ICU admission, but largely recovered 3 months post-ICU admission. Proportion of patients moderately to severely malnourished at ICU admission: 14%; at hospital discharge 38%.

Chapple et al., 2018 [28] (Australia)

Qualitative approach; study not grounded in a specific qualitative methodological framework

To explore the views and attitudes of ICU and ward physicians and nursing practitioners regarding nutrition interventions for TBI patients.

Healthcare providers (18 nurses, 16 physicians) working in ICU or on ward with post-ICU patients

n = 34

N/A

Barriers to nutrition interventions identified by nurses and physicians related to use of feeding tubes, competing priorities of care/nutrition not a top priority, lack of education regarding importance of nutrition.

Merriweather et al., 2018 [29] (Scotland)

Secondary analysis of the RECOVER RCT [24].

To investigate changes occurring in appetite over 12 weeks following ICU discharge.

Critically ill adults requiring > 48 h MV

n = 193

Factors affecting intake:

ICU discharge, 3-, 6-, and 12-month follow-ups: Appetite VAS

Appetite is suppressed (< 5 cm on VAS) at the time of ICU discharge, with no improvements seen throughout hospitalization. 3-months post-discharge, appetite scores increased by 1.7 cm but remained low.

Jarden et al., 2018 [30] (New Zealand)

Service evaluation

Assess oral intake in post-ICU patients up to 1 month following extubation.

Patients admitted to a mixed ICU requiring intubation

n = 79

Oral intake:

Meal intake (proportion of meal tray and use of ONS) assessed daily using intake audit records measured during hospitalization following ICU discharge

62% of patients had inadequate oral intake, defined as consuming < 2/3 of their meal tray, and of these patients, 60% consumed < 1/3 of their meals. One quarter of patients were unable to feed themselves independently.

Ridley et al., 2019 [31] (Australia)

Nested cohort study

Assess dietary intake and assess energy expenditure in the post-ICU hospitalization period.

Critically ill adults with ≥ 1 defined organ system failure requiring MV

n = 32

Energy and protein intake:

EN/PN: calculated daily from flow sheets in the medical record

Oral diets: 24-h recall, food record chart review

Estimation of requirements to assess adequacy:

Indirect calorimetry (n = 12); 25–30 kcal/kg calculated body weight (n = 20) set as actual body weight if BMI < 25 kg/m² or ideal body weight of BMI 23 kg/m² if BMI ≥ 25 kg/m²

Patients receiving oral diets without ONS consumed median 37% and 48% of prescribed calories and protein, respectively. Patients receiving oral diets including ONS consumed median 73% and 68% of prescribed calories and protein, respectively. Adequacy of calorie and protein intake for patients on EN and EN with an oral diet was 62% and 59%, respectively, and 104% and 99%, respectively.

Chapple et al., 2019 [32] (Australia)

Inception cohort study

Evaluate dietary intake, appetite, and gastric emptying 3 months following ICU discharge.

Adults requiring an ICU admission and alive at hospital discharge

n = 51 ICU survivors

n = 25 healthy controls

Energy and protein intake:

Day prior to gastric emptying testing: 24-h recall conducted by a dietitian

Following consumption of carbohydrate drink for gastric emptying test: standard buffet meal (participants ate from a standardized selection of food ad libitum until full)

Body composition:

Weight: self-reported prior to ICU admission; measured at 3-month follow-up (gastric emptying testing day)

Factors affecting intake:

Appetite VAS

Gastric emptying via carbohydrate absorption and breath testing

ICU survivors consumed fewer kcal the day prior to testing, as evaluated using the 24-h recall; on the testing day, intake, assessed via the weighed buffet, did not differ between the groups. No differences in appetite rating or the rate of gastric emptying between ICU survivors and healthy controls were observed.

Wittholz et al., 2020 [33] (Australia)

Prospective observational study

Assess nutritional outcomes in trauma patients following ICU discharge.

Critically ill adult trauma patients requiring MV > 48 h

n = 28

Energy and protein intake:

Determined daily from days 1–5 post-ICU discharge

EN/PN: calculated from daily fluid balance charts

Oral diets: visual estimation of meal components consumed

Estimation of requirements to assess adequacy:

Dietitian prescriptions

Body composition:

Measures taken at ICU discharge and weekly until day 26 or hospital discharge: Weight, QMLT via ultrasound

Global nutritional status assessment:

Hospital discharge: SGA

Functional status assessment:

Measure taken at ICU discharge and weekly until day 26 or hospital discharge: hand-grip strength

Patients receiving oral diets consumed a mean of 54% and 65% of prescribed calories and protein, respectively. Adequacy of calorie and protein intake for patients receiving artificial nutrition (EN, EN with an oral diet, PN) was 87% and 87%, respectively.

Moisey et al., 2021 [34] (Canada)

Prospective observational study

Assess nutritional intake up to 14 days following LMV.

Critically ill patients from a mixed ICU requiring MV > 72 h

n = 19

Energy and protein intake:

EN/PN: calculated daily from flow sheets in the medical record up to day 90 of hospitalization

Oral diets: weighed food records for 7 days and day 14 following LMV

Estimation of requirements to assess adequacy:

Energy and protein prescriptions assessed by the hospital dietitians as part of standard care were extrapolated from the charts

Barriers to intake:

Identified using non-validated checklist of barriers to eating commonly identified in hospitalized patients

Patients receiving oral diets consumed median 47% and 27% of prescribed calories and protein, respectively. Adequacy of calorie and protein intake for patients on EN and EN with an oral diet was 100% and 100%, respectively, and 74% and 75%, respectively. Primary barriers to eating identified included poor appetite, early satiety, taste changes, nausea/vomiting, and disliked the food served.