Bleeding, anaemia, and transfusion: an ounce of prevention is worth a pound of cure

Potential for using simulated altitude as a means of prehabilitation: a physiology study

The current pandemic of surgical complications necessitates urgent and pragmatic innovation to reduce postoperative morbidity and mortality, which are associated with poor pre-operative fitness and anaemia. Exercise prehabilitation is a compelling strategy, but it has proven difficult to establish that it improves outcomes either in isolation or as part of a multimodal approach. Simulated altitude exposure improves performance in athletes and offers a novel potential means of improving cardiorespiratory and metabolic fitness and alleviating anaemia within the prehabilitation window. We aimed to provide an initial physiological foundation for 'altitude prehabilitation' by determining the physiological effects of one week of simulated altitude (FI O2 15%, equivalent to approximately 2438 m (8000 ft)) in older sedentary volunteers. The study used a randomised, double-blind, sham-controlled crossover design. Eight participants spent counterbalanced normoxic and hypoxic weeks in a residential hypoxia facility and underwent repeated cardiopulmonary exercise tests. Mean (SD) age of participants was 64 (7) y and they were unfit, with mean (SD) baseline anaerobic threshold 12 (2) ml.kg-1 .min-1 and mean (SD) peak V̇O2 15 (3) ml.kg-1 .min-1 . Hypoxia was mild (mean (SD) Sp O2 93 (2) %, p < 0.001) and well-tolerated. Despite some indication of greater peak exercise capacity following hypoxia, overall there was no effect of simulated altitude on anaerobic threshold or peak V̇O2 . However, hypoxia induced a substantial increase in mean (SD) haemoglobin of 1.5 (2.7) g.dl-1 (13% increase, p = 0.028). This study has established the concept and feasibility of 'altitude prehabilitation' and demonstrated specific potential for improving haematological fitness. Physiologically, there is value in exploring a possible role for simulated altitude in pre-operative optimisation.

Post-Embolization Hemoglobin Changes: When to Consider Re-intervention

PURPOSE

Decline in hemoglobin (Hgb) levels is common post-embolization, but there is no consensus on the classification of patients based on risk for re-bleeding or re-intervention. The current study evaluated post-embolization Hgb level trends with the goal of understanding the factors predictive of re-bleeding and re-intervention.

MATERIALS AND METHODS

All patients who underwent embolization for gastrointestinal (GI), genitourinary, peripheral, or thoracic arterial hemorrhage from 01/2017 to 01/2022 were reviewed. Data included demographics, periprocedural pRBC transfusion (TF) or pressor requirements, and outcome. Lab data consisted of Hgb values pre-embolization, immediately post-embolization, and daily values on days 1-10 after embolization. Hgb trends were compared between patients across TF and re-bleeding outcomes. Regression model was used to examine factors predictive of re-bleeding and magnitude of Hgb reduction post-embolization.

RESULTS

A total of 199 patients were embolized for active arterial hemorrhage. Perioperative Hgb level trends were similar for all sites and between TF + and TF- patients, showing a decline reaching a nadir within 6 days post-embolization followed by an upward trend. Maximum Hgb drift was predicted by GI embolization (p = 0.018), TF before embolization (p = 0.001), and use of vasopressor (p = 0.000). Patients with Hgb drop  > 15% within the first two days post-embolization had a higher chance of having a re-bleeding episode (p = 0.04).

CONCLUSION

Perioperative Hgb trends showed a consistent downward drift followed by an upward shift, irrespective of TF requirement status or site of embolization. Using a cut-off value of 15% Hgb reduction within the first two days post-embolization may be helpful to assess re-bleeding risk.

Anemia tolerance versus blood transfusion on long-term outcomes after colorectal cancer surgery: A retrospective propensity-score-matched analysis

Background

Perioperative anemia and transfusion are intertwined with each other, and both have adverse impacts on the survival of colorectal cancer (CRC) patients. But the treatment of anemia still relies on transfusion in several countries, which leads us to question the effects of anemia tolerance and transfusion on the long-term outcomes of CRC patients. We investigated the combined effect of preoperative anemia and postoperative anemia and of preoperative anemia and blood transfusion, which imposes a greater risk to survival, to compare the effects of anemia tolerance and transfusion on overall survival (OS) and disease-free survival (DFS) in patients undergoing CRC surgery.

Methods

A retrospective propensity-score-matched analysis included patients with CRC undergoing elective surgery between January 1, 2008, and December 31, 2014. After propensity-score matching, Kaplan–Meier survival analysis and univariable and multivariable Cox proportional hazards models were used to study the prognostic factors for survivals. In univariate and multivariate Cox regression analysis, two novel models were built.

Results

Of the 8,121 patients with CRC, 1,975 (24.3%) and 6,146 (75.7%) patients presented with and without preoperative anemia, respectively. After matching, 1,690 patients remained in each group. In the preoperative anemia and postoperative anemia model, preoperative anemia and postoperative anemia was independent risk factor for OS (HR, 1.202; 95% CI, 1.043–1.385; P=0.011) and DFS (HR, 1.210; 95% CI, 1.050–1.395; P=0.008). In the preoperative anemia and transfusion model, preoperative anemia and transfused was the most dangerous independent prognostic factor for OS (HR, 1.791; 95% CI, 1.339–2.397; P<0.001) and DFS (HR, 1.857; 95% CI, 1.389–2.483; P<0.001). In patients with preoperative anemia, the OS and DFS of patients with transfusion were worse than those of patients without transfusion (P=0.026 in OS; P=0.037 in DFS).

Conclusions

Preoperative anemia and blood transfusion imposed a greater risk to OS and DFS in patients undergoing CRC surgery, indicating that the harm associated with blood transfusion was greater than that associated with postoperative anemia. These findings should encourage clinicians to be vigilant for the timely prevention and treatment of anemia, by appropriately promoting toleration of anemia and restricting the use of blood transfusion in patients with CRC.