Browsing by Subject "Critical care"

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  • Kirkegaard, Hans; Pedersen, Asger Roer; Pettilä, Ville; Hjort, Jakob; Rasmussen, Bodil Steen; de Haas, Inge; Nielsen, Jorgen Feldbaek; Ilkjaer, Susanne; Kaltoft, Anne; Jeppesen, Anni Norgaard; Grejs, Anders Morten; Duez, Christophe Henri Valdemar; Larsen, Alf Inge; Toome, Valdo; Arus, Urmet; Taccone, Fabio Silvio; Storm, Christian; Laitio, Timo; Skrifvars, Markus; Soreide, Eldar (2016)
    Background: The TTH48 trial aims to determine whether prolonged duration (48 hours) of targeted temperature management (TTM) at 33 (+/- 1) degrees C results in better neurological outcomes compared to standard duration (24 hours) after six months in comatose out-of-hospital cardiac arrest (OHCA) patients. Methods: TTH48 is an investigator-initiated, multicentre, assessor-blinded, randomised, controlled superiority trial of 24 and 48 hours of TTM at 33 (+/- 1) degrees C performed in 355 comatose OHCA patients aged 18 to 80 years who were admitted to ten intensive care units (ICUs) in six Northern European countries. The primary outcome of the study is the Cerebral Performance Category (CPC) score observed at six months after cardiac arrest. CPC scores of 1 and 2 are defined as good neurological outcomes, and CPC scores of 3, 4 and 5 are defined as poor neurological outcomes. The secondary outcomes are as follows: mortality within six months after cardiac arrest, CPC at hospital discharge, Glasgow Coma Scale (GCS) score on day 4, length of stay in ICU and at hospital and the presence of any adverse events such as cerebral, circulatory, respiratory, gastrointestinal, renal, metabolic measures, infection or bleeding. With the planned sample size, we have 80% power to detect a 15% improvement in good neurological outcomes at a two-sided statistical significance level of 5%. Discussion: We present a detailed statistical analysis protocol (SAP) that specifies how primary and secondary outcomes should be evaluated. We also predetermine covariates for adjusted analyses and pre-specify sub-groups for sensitivity analyses. This pre-planned SAP will reduce analysis bias and add validity to the findings of this trial on the effect of length of TTM on important clinical outcomes after cardiac arrest.
  • Wiersema, Renske; Koeze, Jacqueline; Hiemstra, Bart; Pettilä, Ville; Perner, Anders; Keus, Frederik; van der Horst, Iwan C. C.; SICS-I Study Grp; Clement, R. P.; Dieperink, W.; Hilbink, D. H.; Klasen, M.; Klaver, M.; Kaufmann, T.; Schokking, L. J.; Sikkens, V. W. (2019)
    Acute kidney injury (AKI) occurs in up to 50% of all critically ill patients and hemodynamic abnormalities are assumed to contribute, but their nature and share is still unclear. We explored the associations between hemodynamic variables, including cardiac index and right ventricular function, and the occurrence of AKI in critically ill patients. In this prospective cohort study, we included all patients acutely admitted to an intensive care unit (ICU). Within 24 h after ICU admission clinical and hemodynamic variables were registered including ultrasonographic measurements of cardiac index and right ventricular function, assessed using tricuspid annular plane systolic excursion (TAPSE) and right ventricular systolic excursion (RV S'). Maximum AKI stage was assessed according to the KDIGO criteria during the first 72 h after admission. Multivariable logistic regression modeling was used including both known predictors and univariable significant predictors of AKI. Secondary outcomes were days alive outside ICU and 90-day mortality. A total of 622 patients were included, of which 338 patients (54%) had at least AKI stage 1 within 72 h after ICU admission. In the final multivariate model higher age (OR 1.01, 95% CI 1.00-1.03, for each year), higher weight (OR 1.03 CI 1.02-1.04, for each kg), higher APACHE IV score (OR 1.02, CI 1.01-1.03, per point), lower mean arterial pressure (OR 1.02, CI 1.01-1.03, for each mmHg decrease) and lower TAPSE (OR 1.05, CI 1.02-1.09 per millimeter decrease) were all independent predictors for AKI in the final multivariate logistic regression model. Sepsis, cardiac index, RV S' and use of vasopressors were not significantly associated with AKI in our data. AKI patients had fewer days alive outside of ICU, and their mortality rate was significantly higher than those without AKI. In our cohort of acutely admitted ICU patients, the incidence of AKI was 54%. Hemodynamic variables were significantly different between patients with and without AKI. A worse right ventricle function was associated with AKI in the final model, whereas cardiac index was not.
  • Wiersema, Renske; Koeze, Jacqueline; Hiemstra, Bart; Pettilä, Ville; Perner, Anders; Keus, Frederik; van der Horst, Iwan C C (Springer International Publishing, 2019)
    Abstract Background Acute kidney injury (AKI) occurs in up to 50% of all critically ill patients and hemodynamic abnormalities are assumed to contribute, but their nature and share is still unclear. We explored the associations between hemodynamic variables, including cardiac index and right ventricular function, and the occurrence of AKI in critically ill patients. Methods In this prospective cohort study, we included all patients acutely admitted to an intensive care unit (ICU). Within 24 h after ICU admission clinical and hemodynamic variables were registered including ultrasonographic measurements of cardiac index and right ventricular function, assessed using tricuspid annular plane systolic excursion (TAPSE) and right ventricular systolic excursion (RV S’). Maximum AKI stage was assessed according to the KDIGO criteria during the first 72 h after admission. Multivariable logistic regression modeling was used including both known predictors and univariable significant predictors of AKI. Secondary outcomes were days alive outside ICU and 90-day mortality. Results A total of 622 patients were included, of which 338 patients (54%) had at least AKI stage 1 within 72 h after ICU admission. In the final multivariate model higher age (OR 1.01, 95% CI 1.00–1.03, for each year), higher weight (OR 1.03 CI 1.02–1.04, for each kg), higher APACHE IV score (OR 1.02, CI 1.01–1.03, per point), lower mean arterial pressure (OR 1.02, CI 1.01–1.03, for each mmHg decrease) and lower TAPSE (OR 1.05, CI 1.02–1.09 per millimeter decrease) were all independent predictors for AKI in the final multivariate logistic regression model. Sepsis, cardiac index, RV S’ and use of vasopressors were not significantly associated with AKI in our data. AKI patients had fewer days alive outside of ICU, and their mortality rate was significantly higher than those without AKI. Conclusions In our cohort of acutely admitted ICU patients, the incidence of AKI was 54%. Hemodynamic variables were significantly different between patients with and without AKI. A worse right ventricle function was associated with AKI in the final model, whereas cardiac index was not.
  • Glassford, Neil J.; Martensson, Johan; Eastwood, Glenn M.; Jones, Sarah L.; Tanaka, Aiko; Wilkman, Erica; Bailey, Michael; Bellomo, Rinaldo; Arabi, Yaseen; Bagshaw, Sean M.; Bannard-Smith, Jonathan; Bin, Du; Dubin, Arnaldo; Duranteau, Jacques; Echeverri, Jorge; Hoste, Eric; Joannidis, Michael; Kashani, Kianoush; Kellum, John; Kulkarni, Atul P.; Landoni, Giovanni; Candal, Christina Lluch; Matejovic, Martin; Yunos, Norazim Modh; Anaes, M.; Nichol, Alistair; Oudemans van Straaten, Heleen; Perner, Anders; Pettila, Ville; Phua, Jason; Hernandez, Glenn; Puxty, Alex; Reinhart, Konrad; Richards, Guy; Schneider, Antoine; Tsuji, Isabella; Uchino, Shigehiko; GLobal OBservational Evaluations I (2016)
    Purpose: The purpose of the study is to understand what clinicians believe defines fluid bolus therapy (FBT) and the expected response to such intervention. Methods: We asked intensive care specialists in 30 countries to participate in an electronic questionnaire of their practice, definition, and expectations of FBT. Results: We obtained 3138 responses. Despite much variation, more than 80% of respondents felt that more than 250 mL of either colloid or crystalloid fluid given over less than 30 minutes defined FBT, with crystalloids most acceptable. The most acceptable crystalloid and colloid for use as FBT were 0.9% saline and 4% albumin solution, respectively. Most respondents believed that one or more of the following physiological changes indicates a response to FBT: a mean arterial pressure increase greater than 10 mm Hg, a heart rate decrease greater than 10 beats per minute, an increase in urinary output by more than 10 mL/h, an increase in central venous oxygen saturation greater than 4%, or a lactate decrease greater than 1 mmol/L. Conclusions: Despite wide variability between individuals and countries, clear majority views emerged to describe practice, define FBT, and identify a response to it. Further investigation is now required to describe actual FBT practice and to identify the magnitude and duration of the physiological response to FBT and its relationship to patient-centered outcomes. (C) 2016 Elsevier Inc. All rights reserved.
  • Perner, Anders; Cecconi, Maurizio; Cronhjort, Maria; Darmon, Michael; Jakob, Stephan M.; Pettilä, Ville; van der Horst, Iwan C. C. (2018)
    Hypovolemia is frequent in patients with sepsis and may contribute to worse outcome. The management of these patients is impeded by the low quality of the evidence for many of the specific components of the care. In this paper, we discuss recent advances and controversies in this field and give expert statements for the management of hypovolemia in patients with sepsis including triggers and targets for fluid therapy and volumes and types of fluid to be given. Finally, we point to unanswered questions and suggest a roadmap for future research.
  • Vahtera, Annukka; Valkonen, Miia; Huhtala, Heini; Pettila, Ville; Kuitunen, Anne (2017)
    Introduction: In intensive care unit (ICU) patients, subcutaneous low-molecular weight heparin thromboprophylaxis results in lower plasma anti-factor Xa (anti-FXa) levels compared to general ward patients. The aim of this study was to examine whether enoxaparin thromboprophylaxis given as a continuous intravenous infusion (CII) results in more constant and predictable anti-FXa concentration than standard subcutaneous bolus (SCB) administration. Materials and methods: This was a prospective, single-blind, multicenter, randomized controlled trial where ICU patients requiring thromboprophylaxis received enoxaparin either 40 mg as a SCB once daily or 40 mg as a CII over 24 h for three consecutive days. The primary outcome was maximum serum anti-FXa concentration (C-max24 (h)) within the first 24 h; the secondary outcome was anti-FXa area under the curve (AUC)((0-24 h)). Trough level was measured at 72 h. Results: Thirty-nine patients were included in the intention to treat analysis. The median anti-FXa C-max24 (h) was 0.05 (interquartile range, IQR, 0.05-0.18) IU/ml in the CII group and 0.18 (IQR, 0.12-0.33) IU/ml in the SCB group (p= 0.05). Median anti-FXa AUC((0-24 h)) was 1.20 (IQR, 0.98-2.88) in the CII and 1.54 (IQR, 1.22-4.12) in the SCB group (p = 0.095). After 72 h, 66.7% of patients in the CII group had a detectable anti-FXa concentration of > 0.1 IU/ml, compared with 16.7% in the SCB group (p = 0.019). Conclusions: Continuous infusion of enoxaparin led to lower anti-FXa C-max24 h than standard SCB administration. No difference in anti-FXa AUC(0-24) (h) was detected.
  • Vahtera, Annukka; Vaara, Suvi; Pettila, Ville; Kuitunen, Anne (2016)
    Background: Critical care patients are prone to venous thromboembolism (VTE) and, thus, pharmacological thromboprophylaxis is generally advised. Low-molecular weight heparins (LMWHs) have become the drug of choice in ICU patients, since their predictable and reproducible dose response. Monitoring their pharmacological effect is not usually necessary except in special occasions (i.e. with obese or renal failure patients), where anti-FXa level measuring is recommended. However, there is neither recommendation of adequate anti-FXa levels in critically ill patients nor is it known whether peak or trough level should be measured. The aim of this systematic review was to evaluate the recommended LMWH doses, and the reasons to monitor anti-FXa levels. Methods: We searched MEDLINE, Scopus, Cochrane Central Register of Controlled Trials and ClinicalTrials.com to identify all potentially relevant studies. Prospective studies done in critically ill patients were included if at least one anti-FXa level (i.e. peak or trough) after any specified LMWH thromboprophylaxis dose was measured. Results: Total 18 eligible studies including 1644 patients were included. There was a wide variation in the median peak anti-FXa levels ( Conclusion: Based on the current literature, no definite conclusions can be drawn on targeted anti-FXa level in critically ill patients when using LMWH thromboprophylaxis. (C) 2016 Elsevier Ltd. All rights reserved.
  • Tolonen, Matti; Sallinen, Ville; Mentula, Panu; Leppaniemi, Ari (2016)
    The aim of this study was to analyse preoperative risk factors for mortality or intensive care unit admission to describe severe peritonitis. This was a single academic centre retrospective study of consecutive adult patients operated for diffuse secondary peritonitis between 2012 and 2013. Patients with appendicitis or cholecystitis were excluded. Independent risk factors were identified using binary and ordinal logistic regression. A total of 223 patients were analysed. Overall 30-day mortality was 14.5 %. Postoperatively, 32.3 % of patients were admitted into the intensive care unit (ICU). Independent risk factors for severe peritonitis were septic shock (odds ratio (OR) 37.94, 95 % confidence interval (CI) 14.52-99.13), chronic kidney insufficiency (OR 5.98 (95 % CI 1.56-22.86), severe sepsis (OR 4.80, 95 % CI 2.10-10.65) and cardiovascular disease (OR 2.58, 95 % CI 1.22-5.47). Patients lacking these factors had no mortality. ICU admission was refused in 24 (10.8 %) patients with 70.8 % mortality. In a subgroup of patients without treatment limitations (n = 190), independent risk factors for weighted outcome of ICU admission or mortality were septic shock (OR 11.89, 95 % CI 4.98-28.40), severe sepsis (OR 5.56, 95 % CI 2.39-12.89), metastatic malignant disease or lymphoma (OR 3.11, 95 % CI 1.34-7.20) and corticosteroid use (OR 2.98, 95 % CI 1.18-7.51). When receiving full level of care, patients with preoperative organ dysfunctions in this subgroup had 8.2 % 30-day mortality. Preoperative organ dysfunctions, chronic kidney insufficiency and cardiovascular disease are the most important risk factors for severe peritonitis. Without these risk factors, patients had no mortality.
  • AID-ICU Cohort Study Co-authors; Loisa, Pekka (2018)
    We assessed the prevalence and variables associated with haloperidol use for delirium in ICU patients and explored any associations of haloperidol use with 90-day mortality. All acutely admitted, adult ICU patients were screened during a 2-week inception period. We followed the patient throughout their ICU stay and assessed 90-day mortality. We assessed patients and their variables in the first 24 and 72 h in ICU and studied their association together with that of ICU characteristics with haloperidol use. We included 1260 patients from 99 ICUs in 13 countries. Delirium occurred in 314/1260 patients [25% (95% confidence interval 23-27)] of whom 145 received haloperidol [46% (41-52)]. Other interventions for delirium were benzodiazepines in 36% (31-42), dexmedetomidine in 21% (17-26), quetiapine in 19% (14-23) and olanzapine in 9% (6-12) of the patients with delirium. In the first 24 h in the ICU, all subtypes of delirium [hyperactive, adjusted odds ratio (aOR) 29.7 (12.9-74.5); mixed 10.0 (5.0-20.2); hypoactive 3.0 (1.2-6.7)] and circulatory support 2.7 (1.7-4.3) were associated with haloperidol use. At 72 h after ICU admission, circulatory support remained associated with subsequent use of haloperidol, aOR 2.6 (1.1-6.9). Haloperidol use within 0-24 h and within 0-72 h of ICU admission was not associated with 90-day mortality [aOR 1.2 (0.5-2.5); p = 0.66] and [aOR 1.9 (1.0-3.9); p = 0.07], respectively. In our study, haloperidol was the main pharmacological agent used for delirium in adult patients regardless of delirium subtype. Benzodiazepines, other anti-psychotics and dexmedetomidine were other frequently used agents. Haloperidol use was not statistically significantly associated with increased 90-day mortality.
  • Hjortrup, Peter B.; Haase, Nicolai; Bundgaard, Helle; Thomsen, Simon L.; Winding, Robert; Pettilä, Ville; Aaen, Anne; Lodahl, David; Berthelsen, Rasmus E.; Christensen, Henrik; Madsen, Martin B.; Winkel, Per; Wetterslev, Jorn; Perner, Anders; CLASSIC Trial Grp; Scandinavian Critical Care Trials (2016)
    Purpose: We assessed the effects of a protocol restricting resuscitation fluid vs. a standard care protocol after initial resuscitation in intensive care unit (ICU) patients with septic shock. Methods: We randomised 151 adult patients with septic shock who had received initial fluid resuscitation in nine Scandinavian ICUs. In the fluid restriction group fluid boluses were permitted only if signs of severe hypoperfusion occurred, while in the standard care group fluid boluses were permitted as long as circulation continued to improve. Results: The co-primary outcome measures, resuscitation fluid volumes at day 5 and during ICU stay, were lower in the fluid restriction group than in the standard care group [ mean differences -1.2 L (95 % confidence interval -2.0 to -0.4); p <0.001 and -1.4 L (-2.4 to -0.4) respectively; p <0.001]. Neither total fluid inputs and balances nor serious adverse reactions differed statistically significantly between the groups. Major protocol violations occurred in 27/75 patients in the fluid restriction group. Ischaemic events occurred in 3/75 in the fluid restriction group vs. 9/76 in the standard care group (odds ratio 0.32; 0.08-1.27; p = 0.11), worsening of acute kidney injury in 27/73 vs. 39/72 (0.46; 0.23-0.92; p = 0.03), and death by 90 days in 25/75 vs. 31/76 (0.71; 0.36-1.40; p = 0.32). Conclusions: A protocol restricting resuscitation fluid successfully reduced volumes of resuscitation fluid compared with a standard care protocol in adult ICU patients with septic shock. The patient-centred outcomes all pointed towards benefit with fluid restriction, but our trial was not powered to show differences in these exploratory outcomes.
  • Saviluoto, Anssi; Björkman, Johannes; Olkinuora, Anna; Virkkunen, Ilkka; Kirves, Hetti; Setala, Piritta; Pulkkinen, Ilkka; Laukkanen-Nevala, Paivi; Raatiniemi, Lasse; Jäntti, Helena; Iirola, Timo; Nurmi, Jouni (2020)
    Background: Helicopter Emergency Medical Services (HEMS) play an important role in prehospital care of the critically ill. Differences in funding, crew composition, dispatch criteria and mission profile make comparison between systems challenging. Several systems incorporate databases for quality control, performance evaluation and scientific purposes. FinnHEMS database was incorporated for such purposes following the national organization of HEMS in Finland 2012. The aims of this study are to describe information recorded in the database, data collection, and operational characteristics of Finnish HEMS during 2012-2018. Methods: All dispatches of the six Finnish HEMS units recorded in the national database from 2012 to 2018 were included in this observational registry study. Five of the units are physician staffed, and all are on call 24/7. The database follows a template for uniform reporting in physician staffed pre-hospital services, exceeding the recommended variables of relevant guidelines. Results: The study included 100,482 dispatches, resulting in 33,844 (34%) patient contacts. Variables were recorded with little or no missing data. A total of 16,045 patients (16%) were escorted by HEMS to hospital, of which 2239 (2%) by helicopter. Of encountered patients 4195 (4%) were declared deceased on scene. The number of denied or cancelled dispatches was 66,638 (66%). The majority of patients were male (21,185, 63%), and the median age was 57.7 years. The median American Society of Anesthesiologists Physical Scale classification was 2 and Eastern Cooperative Oncology Group performance class 0. The most common reason for response was trauma representing 26% (8897) of the patients, followed by out-of-hospital cardiac arrest 20% (6900), acute neurological reason excluding stroke 13% (4366) and intoxication and related psychiatric conditions 10% (3318). Blunt trauma (86%, 7653) predominated in the trauma classification. Conclusions: Gathering detailed and comprehensive data nationally on all HEMS missions is feasible. A national database provides valuable insights into where the operation of HEMS could be improved. We observed a high number of cancelled or denied missions and a low percentage of patients transported by helicopter. The medical problem of encountered patients also differs from comparable systems.
  • Saviluoto, Anssi; Björkman, Johannes; Olkinuora, Anna; Virkkunen, Ilkka; Kirves, Hetti; Setälä, Piritta; Pulkkinen, Ilkka; Laukkanen-Nevala, Päivi; Raatiniemi, Lasse; Jäntti, Helena; Iirola, Timo; Nurmi, Jouni (BioMed Central, 2020)
    Abstract Background Helicopter Emergency Medical Services (HEMS) play an important role in prehospital care of the critically ill. Differences in funding, crew composition, dispatch criteria and mission profile make comparison between systems challenging. Several systems incorporate databases for quality control, performance evaluation and scientific purposes. FinnHEMS database was incorporated for such purposes following the national organization of HEMS in Finland 2012. The aims of this study are to describe information recorded in the database, data collection, and operational characteristics of Finnish HEMS during 2012–2018. Methods All dispatches of the six Finnish HEMS units recorded in the national database from 2012 to 2018 were included in this observational registry study. Five of the units are physician staffed, and all are on call 24/7. The database follows a template for uniform reporting in physician staffed pre-hospital services, exceeding the recommended variables of relevant guidelines. Results The study included 100,482 dispatches, resulting in 33,844 (34%) patient contacts. Variables were recorded with little or no missing data. A total of 16,045 patients (16%) were escorted by HEMS to hospital, of which 2239 (2%) by helicopter. Of encountered patients 4195 (4%) were declared deceased on scene. The number of denied or cancelled dispatches was 66,638 (66%). The majority of patients were male (21,185, 63%), and the median age was 57.7 years. The median American Society of Anesthesiologists Physical Scale classification was 2 and Eastern Cooperative Oncology Group performance class 0. The most common reason for response was trauma representing 26% (8897) of the patients, followed by out-of-hospital cardiac arrest 20% (6900), acute neurological reason excluding stroke 13% (4366) and intoxication and related psychiatric conditions 10% (3318). Blunt trauma (86%, 7653) predominated in the trauma classification. Conclusions Gathering detailed and comprehensive data nationally on all HEMS missions is feasible. A national database provides valuable insights into where the operation of HEMS could be improved. We observed a high number of cancelled or denied missions and a low percentage of patients transported by helicopter. The medical problem of encountered patients also differs from comparable systems.
  • Hemilä, Harri; Chalker, Elizabeth (2020)
    Background Our recent meta-analysis indicated that vitamin C may shorten the length of ICU stay and the duration of mechanical ventilation. Here we analyze modification of the vitamin C effect on ventilation time, by the control group ventilation time (which we used as a proxy for severity of disease in the patients of each trial). Methods We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials and reference lists of relevant publications. We included controlled trials in which the administration of vitamin C was the only difference between the study groups. We did not limit our search to randomized trials and did not require placebo control. We included all doses and all durations of vitamin C administration. One author extracted study characteristics and outcomes from the trial reports and entered the data in a spreadsheet. Both authors checked the data entered against the original reports. We used meta-regression to examine whether the vitamin C effect on ventilation time depends on the duration of ventilation in the control group. Results We identified nine potentially eligible trials, eight of which were included in the meta-analysis. We pooled the results of the eight trials, including 685 patients in total, and found that vitamin C shortened the length of mechanical ventilation on average by 14% (P = 0.00001). However, there was significant heterogeneity in the effect of vitamin C between the trials. Heterogeneity was fully explained by the ventilation time in the untreated control group. Vitamin C was most beneficial for patients with the longest ventilation, corresponding to the most severely ill patients. In five trials including 471 patients requiring ventilation for over 10 h, a dosage of 1-6 g/day of vitamin C shortened ventilation time on average by 25% (P <0.0001). Conclusions We found strong evidence that vitamin C shortens the duration of mechanical ventilation, but the magnitude of the effect seems to depend on the duration of ventilation in the untreated control group. The level of baseline illness severity should be considered in further research. Different doses should be compared directly in future trials.
  • Hemilä, Harri; Chalker, Elizabeth (BioMed Central, 2020)
    Abstract Background Our recent meta-analysis indicated that vitamin C may shorten the length of ICU stay and the duration of mechanical ventilation. Here we analyze modification of the vitamin C effect on ventilation time, by the control group ventilation time (which we used as a proxy for severity of disease in the patients of each trial). Methods We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials and reference lists of relevant publications. We included controlled trials in which the administration of vitamin C was the only difference between the study groups. We did not limit our search to randomized trials and did not require placebo control. We included all doses and all durations of vitamin C administration. One author extracted study characteristics and outcomes from the trial reports and entered the data in a spreadsheet. Both authors checked the data entered against the original reports. We used meta-regression to examine whether the vitamin C effect on ventilation time depends on the duration of ventilation in the control group. Results We identified nine potentially eligible trials, eight of which were included in the meta-analysis. We pooled the results of the eight trials, including 685 patients in total, and found that vitamin C shortened the length of mechanical ventilation on average by 14% (P = 0.00001). However, there was significant heterogeneity in the effect of vitamin C between the trials. Heterogeneity was fully explained by the ventilation time in the untreated control group. Vitamin C was most beneficial for patients with the longest ventilation, corresponding to the most severely ill patients. In five trials including 471 patients requiring ventilation for over 10 h, a dosage of 1–6 g/day of vitamin C shortened ventilation time on average by 25% (P < 0.0001). Conclusions We found strong evidence that vitamin C shortens the duration of mechanical ventilation, but the magnitude of the effect seems to depend on the duration of ventilation in the untreated control group. The level of baseline illness severity should be considered in further research. Different doses should be compared directly in future trials.