Hyperlactatemia, Intraoperative Hypothermia, Nephrectomy / Methods
Conditions
Keywords
prewarming, Preoperative warming, Perioperative hypothermia, serum lactate, Nephrectomy, Anesthesia, Intensive care unit, Postoperative complications
Brief summary
The goal of this observational study is to learn whether warming patients before surgery, called "prewarming," affects blood lactate levels (a marker of how well tissues are getting oxygen) and recovery in adults having planned (elective) kidney removal surgery (nephrectomy). The main questions this study aims to answer are: * Does prewarming lower the rise in blood lactate seen during and after surgery? * Does prewarming affect time spent in the intensive care unit (ICU), the need for a blood transfusion, or the rate of complications after surgery? Researchers will compare two groups of adults having this surgery. One group receives brief active warming before anesthesia (the "prewarming" group). The other group does not receive this warming (the "control" group). The anesthesia team decides whether to use prewarming and for how long, as part of routine care; the study does not change this decision. Researchers will compare the two groups to see whether prewarming is linked to lower lactate levels and better recovery. Participants will: * Receive their usual, routine surgery and anesthesia care * Have blood pressure, heart rate, body temperature, and blood tests, including lactate, checked before and after surgery, as already done in routine care * Have their ICU stay, need for blood transfusion, and any complications recorded This study does not add any extra tests, procedures, or blood draws beyond routine clinical care.
Detailed description
Nephrectomy is a major surgical procedure, performed via open or laparoscopic approaches, that is associated with a substantial physiological stress response. Reduced tissue perfusion and increased anaerobic metabolism during major surgery can raise serum lactate levels, and maintaining perioperative metabolic stability is an important goal in these patients. Prewarming refers to active warming of a patient's body surface before induction of anesthesia, with the aim of reducing intraoperative core-temperature drop and its downstream effects on tissue perfusion and oxygenation. Clinical practice regarding the use and duration of prewarming varies among anesthesiologists, and there is no fixed institutional protocol dictating whether, or for how long, it should be applied. This is a prospective, single-center, observational study conducted over a one-year period. Consecutive adult patients undergoing elective nephrectomy who meet the eligibility criteria will be enrolled and followed as part of routine clinical care (see Eligibility Criteria for full details). Whether a given patient receives prewarming, and for how long (typically 10-15 minutes when used), is determined solely by the anesthesia team providing care in the operating room; the study does not intervene in this clinical decision or modify usual care in any way. Outcomes will be compared between patients who receive prewarming and those who do not. For each patient, a range of preoperative and postoperative physiological and laboratory parameters is recorded as part of routine perioperative monitoring (see Outcome Measures for the specific parameters and their timing). In addition, length of stay in the intensive care unit, need for blood transfusion, and the occurrence and type of postoperative complications are documented. All data are obtained from existing anesthesia records, nursing charts, laboratory results, intensive care information systems, and patient files, and are transcribed onto a predefined case report form; the study does not add any invasive procedures, blood draws, or deviations from routine clinical protocol. Continuous variables will be compared between the prewarming and control groups using the independent-samples t-test or Mann-Whitney U test, as appropriate, and categorical variables will be compared using the chi-square test or Fisher's exact test. Regression analysis will be used to examine associations between prewarming and outcomes. A p-value \<0.05 will be considered statistically significant. A power analysis (G\*Power v3.1.9.2), assuming a medium effect size (Cohen's d=0.5) for the primary between-group lactate comparison, indicated that at least 64 participants per group (128 total) would be needed to achieve 80% power at α=0.05.
Interventions
DEVICEPreoperative active warming (prewarming)
Application of an active warming device to the patient's body surface during operating room preparation, before induction of anesthesia, for approximately 10-15 minutes at the discretion of the anesthesia team. The decision to apply prewarming, and its duration, follows routine clinical practice and is not standardized by the study protocol.
Sponsors
Beyzanur Aydoğdu
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
* Scheduled for elective nephrectomy * Adults aged 18-90 years * ASA (American Society of Anesthesiologists) physical status classification I-III * Signed informed consent form
Exclusion criteria
* Emergency nephrectomy * Concurrent additional major surgical procedure planned in the same session * Age under 18 or over 90 years * ASA physical status classification IV or higher * Incomplete preoperative records (missing pre- or postoperative measurement of at least one primary outcome variable)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Serum Lactate Concentration | From the preoperative assessment to 24 hours after surgery | Change in serum lactate concentration from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Systolic and Diastolic Blood Pressure | From the preoperative assessment to 24 hours after surgery | Changes in systolic and diastolic arterial blood pressure from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Change in Heart Rate | From the preoperative assessment to 24 hours after surgery | Change in heart rate from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Change in Body Temperature | From the preoperative assessment to 24 hours after surgery | Change in body temperature from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Change in Hemoglobin Level | From the preoperative assessment to 24 hours after surgery | Change in hemoglobin concentration from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Change in Hematocrit | From the preoperative assessment to 24 hours after surgery | Change in hematocrit from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Change in Serum Osmolality | From the preoperative assessment to 24 hours after surgery | Change in serum osmolality from the preoperative assessment to the postoperative assessment, compared between the prewarming and control groups. |
| Length of Intensive Care Unit Stay | Up to 48 hours after surgery | Duration of stay in the intensive care unit, compared between the prewarming and control groups. |
| Need for Blood Transfusion | During the first 48 hours after surgery | Proportion of patients requiring blood transfusion and the total number of units transfused during the first 48 hours after surgery, compared between the prewarming and control groups. |
| Incidence of Postoperative Complications | From surgery to 24 hours after surgery | Presence and type of postoperative complications (respiratory, cardiac, renal, infectious, hematologic, or other), compared between the prewarming and control groups. |
Countries
Turkey (Türkiye)
Outcome results
None listed