Impact of standardized nursing protocols in the post-anesthesia care unit on patient safety during recovery from anesthesia: A meta-analysis

Abstract

Background:

To systematically evaluate the impact of standardized nursing protocols in the post-anesthesia care unit (PACU) on patient safety, recovery efficiency, and quality of care during the post-anesthesia transition.

Methods:

A systematic literature search was conducted across major databases, including PubMed, Embase, and Web of Science, to identify randomized controlled trials and observational studies comparing standardized PACU nursing protocols with conventional care. The search period extended from database inception to January 20, 2026. Two reviewers independently screened literature, extracted data, and assessed risk of bias. Meta-analysis was performed using RevMan 5.4 and Stata 17.0, with results expressed as mean differences (MD) or odds ratios (OR) with 95% confidence intervals (CI).

Results:

A total of 14 studies were included (11 randomized controlled trials and 3 cohort studies), encompassing 4268 patients. Meta-analysis demonstrated that, compared with conventional care, the implementation of standardized nursing protocols significantly reduced the overall incidence of adverse events (OR = 0.37, 95% CI: 0.23–0.60, P < .001) and shortened PACU length of stay (MD = −10.65 minutes, 95% CI: −19.10 to −2.19, P = .01). Furthermore, the standardized protocols were associated with significantly improved patient comfort scores (MD = 1.88, 95% CI: 1.63–2.12, P < .001) and higher nursing satisfaction rates (OR = 3.18, 95% CI: 2.01–5.02, P < .001). Subgroup and sensitivity analyses confirmed the robustness of these findings.

Conclusion:

Current evidence indicates that standardized nursing protocols in the PACU significantly enhance patient safety, optimize recovery efficiency, and improve the patient experience. These findings support the widespread clinical adoption and refinement of evidence-based standardized nursing models to minimize perioperative risks.

1. Introduction

The post-anesthesia care unit (PACU) serves as a pivotal transition zone for patients emerging from general anesthesia, facilitating continuous monitoring and the timely management of residual anesthetic effects and early postoperative complications.^[1,2] As surgical techniques evolve and the patient population becomes increasingly elderly and complex, the heterogeneity of post-anesthetic conditions has intensified, thereby elevating the clinical criticality of PACU care.^[3] Globally, approximately 300 million surgical procedures are performed annually. Adverse events occur in 10% to 15% of cases within the first 24 hours post-surgery, with PACU-stage complications including respiratory depression, emergence agitation, and hypotension identified as significant determinants of poor postoperative outcomes.^[4,5] To address these challenges, standardized nursing protocols have emerged as an evidence-based management model designed to homogenize PACU care. These protocols encompass critical workflows such as patient handover, vital sign monitoring, pain management, and the early detection of complications.^[6] While medical institutions worldwide have increasingly adopted these standardized practices, existing literature reports inconsistent efficacy outcomes. Certain studies indicate that standardized protocols significantly abbreviate PACU length of stay and mitigate postoperative complication rates; conversely, findings from smaller-scale or single-center cohorts suggest limited impact on patient prognosis.^[7] This discrepancy highlights the absence of a unified evidentiary consensus to guide clinical administration and policy implementation. Meta-analysis, a cornerstone of evidence-based medicine, offers a mechanism to enhance statistical power by systematically synthesizing data from multiple independent studies, thus yielding more robust conclusions.^[8] To date, systematic reviews regarding PACU care quality have predominantly focused on isolated complications or specific surgical sub-specialties, leaving a gap in the comprehensive evaluation of standardized nursing protocols.^[9] Consequently, this study utilizes meta-analysis to systematically review relevant domestic and international literature to evaluate the impact of standardized PACU nursing protocols on patient safety during anesthesia recovery, with the ultimate objective of providing rigorous evidence to optimize perioperative management.

2. Methods

2.1. Study design and protocol

This systematic review and meta-analysis was conducted in strict adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to ensure methodological transparency and standardization. The study protocol was designed to evaluate the efficacy of standardized nursing protocols in the PACU.

2.2. Search strategy and data sources

A comprehensive literature search was executed across major English and Chinese databases, including PubMed, Embase, and Web of Science, covering the period from their respective inceptions to January 20, 2026. The search strategy employed a combination of Medical Subject Headings and free-text keywords using Boolean logic. Key search terms included “Post-Anesthesia Care Unit,” “PACU,” “standardized nursing protocol,” “standardized care protocol,” “post-anesthesia recovery,” “safety,” and “complications.” For instance, the syntax utilized in PubMed was: (“Post-Anesthesia Care Unit” OR PACU) AND (“standardized nursing” OR “standardized care protocol”) AND (“post-anesthesia recovery” OR “perioperative safety” OR complications). To minimize publication bias, supplementary manual searches were conducted within the reference lists of included studies and core journals. In addition, clinical trial registries, such as ClinicalTrials.gov, were queried to identify relevant unpublished gray literature.

2.3. Eligibility criteria

Study selection was governed by predefined inclusion and exclusion criteria. Eligible studies included randomized controlled trials (RCTs), cohort studies, and case-control studies that compared standardized nursing protocols against conventional care. Participants were defined as adults (aged ≥18 years) undergoing general anesthesia and subsequent PACU recovery. The intervention group consisted of patients managed under a standardized nursing protocol, defined as an evidence-based, structured plan encompassing patient handover, vital sign monitoring, pain management, complication surveillance, and discharge assessment. The control group received routine institutional care. Studies were excluded if they involved pediatric populations, pregnant patients, emergency surgeries, or individuals with severe preexisting organ dysfunction (e.g., significant cardiac, pulmonary, hepatic, or renal impairment). Non-original research, including reviews, case reports, and conference abstracts without available full texts, was also excluded.

2.4. Data extraction and outcome measures

Two investigators independently screened titles and abstracts to exclude irrelevant citations, followed by a full-text review of potential candidates. Data were extracted using a standardized form, capturing: study characteristics (first author, publication year, region, design), participant demographics (sample size, age, gender, surgical category), intervention specifics (protocol components and conventional care descriptors), and outcome data. Discrepancies during screening or extraction were resolved through consensus or consultation with a third reviewer.

The primary outcome measure was the aggregate incidence of PACU complications, including respiratory depression, hypotension, hypertension, emergence agitation, and postoperative nausea and vomiting. Secondary outcomes included PACU length of stay, readmission rates within 24 hours post-surgery, and quality of recovery metrics, such as the Aldrete score at discharge.

2.5. Quality assessment of included studies

Methodological quality was appraised independently by 2 reviewers. For RCTs, the Cochrane Risk of Bias tool (RoB 2) was employed to evaluate domains including randomization, allocation concealment, blinding, and outcome reporting. Observational studies were assessed using the Newcastle-Ottawa Scale, which evaluates selection, comparability, and outcome ascertainment; studies achieving a score of ≥7 out of 9 were classified as high quality.

2.6. Statistical analysis

Meta-analysis was performed using RevMan (version 5.4; The Cochrane Collaboration) and Stata (version 17.0; StataCorp LLC). Dichotomous outcomes were expressed as risk ratios with 95% confidence intervals (CIs), while continuous variables were analyzed using mean differences (MD) or standardized MD with 95% CIs. Statistical heterogeneity was quantified using the I² statistic and Q test. A fixed-effect model was applied when heterogeneity was low (I² ≤ 50%, P ≥ .1); conversely, a random-effects model was utilized for significant heterogeneity (I² > 50%, P < .1). To investigate sources of heterogeneity, subgroup analyses were stratified by study design (RCT vs observational), surgical specialty, and protocol comprehensiveness. Sensitivity analyses were conducted by sequentially omitting individual studies to test the robustness of pooled results. Publication bias was assessed via funnel plots and the Egger test for outcomes including 10 or more studies, with a P value <.05 indicating statistical significance.

3. Results

3.1. Literature selection and study characteristics

The initial database search identified 526 potentially relevant records. Following the removal of 138 duplicates, 388 unique records underwent title and abstract screening. This process resulted in the exclusion of 357 records that failed to meet eligibility criteria, such as non-relevant outcomes, case reports, and reviews. The remaining 31 articles were subjected to full-text review, from which 14 studies were ultimately selected for inclusion. These comprised 11 RCTs and 3 cohort studies, as detailed in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram (Fig. 1). The final analytical cohort encompassed 4268 patients, distributed between the intervention group (n = 2145), which received standardized PACU nursing protocols, and the control group (n = 2123), managed with routine care. Table 1 summarizes the core characteristics of these studies,^[10–23] including publication details, regional distribution, sample sizes, surgical classifications, and specific components of the nursing protocols.

Figure 1.

Document inclusion process. PACU = post-anesthesia care unit, PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Table 1.

General characteristics of included studies.

Author & year	Surgical type/ASA physical status classification	Sample size		Main standardized nursing interventions in PACU	Age		Gender (male)		Study design
		OG	CG		OG	CG	OG	CG
Aasvang 2017[10]	Total hip arthroplasty	670	689	Motor function assessment	68 ± 9	68 ± 10	334 (49.85)	362 (52.54)	RCT
Chen 2024[11]	ASA Ⅰ–Ⅳ	2949	2860	Standardized anesthesia recovery protocol	56.79 ± 17.02	56.96 ± 17.35	1318 (44.7)	1284 (44.9)	RCT
Jaulin 2021[12]	ASA Ⅰ–Ⅳ	266	267	Standardized handover process and checklist	56.5 ± 17.2	56.7 ± 16.8	152 (57.1)	133 (49.8)	Before-after controlled trial
Klein 2017[13]	General anesthesia surgery	50	50	Standardized handover process	–	–	–	–	Before-after controlled trial
Kobelt 2014[14]	General anesthesia surgery	448	394	Standardized opioid administration	48.994 ± 16.904	48.994 ± 16.904	452	390	RCT
Qin 2024[15]	Laparoscopic gynecological surgery	90	90	Early oral rehydration as needed	32.330 ± 6.448	31.660 ± 6.502	0	0	RCT
Qin 2025[16]	ASA Ⅰ–Ⅲ	300	300	Programmed nursing management intervention	46.3 ± 9.8	45.8 ± 10.2	172 (57.33)	168 (56.00)	Retrospective cohort study
Tan 2011[17]	ASA Ⅰ&Ⅱ	60	60	Patient-controlled analgesia (NCA) protocol	45.7 ± 13.7	48.5 ± 11.5	–	–	RCT
Thorner 2022[18]	General anesthesia surgery	69	100	Oxygen supplementation	–	–	41 (59.42)	48 (48.00)	RCT
Wang 2025[19]	ASA Ⅱ–Ⅲ	100	100	Clinical nursing pathway	–	–	–	–	RCT
Wilnerzon 2024[20]	Colorectal surgery	72	72	Immediate mobilization	71 ± 10	71 ± 11	38 (52.78)	45 (62.50)	RCT
Xiao 2019[21]	General anesthesia surgery	120	120	Detailed nursing management	–	–	45 (37.50)	48 (40.00)	RCT
Zheng 2024[22]	ASA Ⅰ–Ⅱ	100	100	Precise temperature control nursing	50 ± 8	51 ± 9	–	–	RCT
Zhong 2026[23]	ASA Ⅰ–Ⅲ	130	130	Enhanced Recovery After Surgery (ERAS)	55.14 ± 14.45	52.65 ± 14.76	56 (43.08)	55 (42.31)	RCT

ASA = American Society of Anesthesiologists, CG = control group, OG = observation group, NCA = nurse-controlled analgesia, PACU = post-anesthesia care unit, RCT = randomized controlled trial.

3.2. Methodological quality assessment

Risk of bias assessment for the 11 RCTs^{[10,11,14,15,17–23]} indicated a moderate overall risk. Seven studies provided explicit descriptions of random sequence generation (e.g., computer-generated randomization), while 5 detailed allocation concealment methods. Double-blinding of both investigators and participants was confirmed in 3 trials. Importantly, no selective reporting bias was detected, and outcome data were complete across all trials. For the 3 non-randomized cohort studies,^[12,13,16] methodological quality was evaluated as high using the Newcastle-Ottawa Scale, with all studies scoring ≥7 points (range: 7–8). Specific domain scores indicated robust selection processes and outcome ascertainment (Fig. 2 and Table 2).

Figure 2.

Risk of bias assessment results for RCTs. RCT = randomized controlled trial.

Table 2.

NOS scores for non-randomized controlled trials.

First author’s publication year	Selection 0–4	Comparability 2	Outcome 3	NOS score
Jaulin 2021	3	2	2	7
Klein 2017	4	2	1	7
Qin 2025	4	2	2	8

NOS = Newcastle-Ottawa Scale.

3.3. Meta-analysis of clinical outcomes

3.3.1. Incidence of adverse events

Eleven studies^{[10–13,15,16,18–20,22,23]} provided data on the incidence of adverse events. Employing a random-effects model due to moderate heterogeneity (I² = 48%), the pooled analysis demonstrated that standardized nursing protocols significantly reduced the risk of adverse events compared with routine care (odds ratio [OR] = 0.37, 95% CI: 0.23–0.60; Z = 4.04, P < .001; Fig. 3).

Figure 3.

Forest plot for the effect of standardized nursing protocols on PACU length of stay. CI = confidence interval, IV = inverse variance, PACU = post-anesthesia care unit.

3.3.2. PACU length of stay

Data on PACU length of stay were available from 11 studies.^{[14,15,17,22]} Significant heterogeneity was observed (I² = 100%); consequently, a random-effects model was utilized. The analysis revealed a significant reduction in length of stay for the intervention group, with a pooled MD of −10.65 minutes (95% CI: −19.10 to −2.19; Z = 2.47, P = .01; Fig. 4).

Figure 4.

Forest plot for the effect of standardized nursing protocols on patient comfort scores. CI = confidence interval, IV = inverse variance, SD = standard deviation.

3.3.3. Patient comfort and satisfaction

Patient comfort scores were reported in 4 studies.^{[14,15,17,22]} The pooled analysis indicated a significant improvement in comfort levels associated with the standardized protocol (MD = 1.88, 95% CI: 1.63–2.12; Z = 15.08, P < .001), with substantial heterogeneity (I² = 61%; Fig. 5). In addition, 3 studies^[16,21,23] assessed patient satisfaction with nursing care. Using a fixed-effects model (I²² =  = 12%), the standardized protocol group demonstrated significantly higher odds of satisfaction (OR = 3.18, 95% CI: 2.01–5.02; Z = 4.97, P < .001; Fig. 6).

Figure 5.

Forest plot for the effect of standardized nursing protocols on the incidence of adverse events. M-H = Mantel-Haenszel.

Figure 6.

Forest plot for the effect of standardized nursing protocols on patient satisfaction with nursing care. CI = confidence interval, M-H = Mantel-Haenszel.

3.4. Subgroup analyses

To investigate the sources of the high heterogeneity (I² = 100%) observed in PACU length of stay, subgroup analyses were stratified by study design and surgical specialty. Stratification by study design revealed consistent reductions in length of stay for both RCTs (MD = −9.82; 95% CI: −18.56 to −1.08) and non-randomized trials (MD = −12.76; 95% CI: −22.34 to −3.18). The test for subgroup differences was non-significant (P = .72), suggesting that study design did not primarily drive the observed heterogeneity. Similarly, stratification by surgical type (general surgery, orthopedics, gynecology/obstetrics) showed consistent efficacy of the standardized protocol across all specialties, yet high heterogeneity persisted within subgroups (I² = 100% for all). This suggests that variations in protocol implementation or baseline patient acuity may contribute to the residual variance.

Conversely, subgroup analysis for adverse events indicated that the protective effect of the standardized protocol was consistent across RCTs (OR = 0.35) and cohort studies (OR = 0.42). Heterogeneity within these subgroups was notably lower (I² = 42% and 55%, respectively) compared with the length of stay outcome.

3.5. Sensitivity analysis and publication bias

The robustness of the PACU length of stay findings was confirmed via leave-one-out sensitivity analysis. The pooled MD remained statistically significant across all iterations, ranging from −12.13 to −9.28 (all P < .05). Furthermore, the exclusion of 3 lower-quality RCTs (lacking allocation concealment descriptions) yielded a pooled MD of −10.17 (95% CI: −18.92 to −1.42; P = .02), indicating that study quality did not disproportionately influence the primary conclusions. Publication bias for the length of stay outcome was assessed using a funnel plot and the Egger test. The funnel plot exhibited general symmetry, and the Egger test (t = 1.25, P = .24) confirmed the absence of significant publication bias (Fig. 7).

Figure 7.

Funnel plot for the assessment of publication bias. MD = mean differences. SE = standard error.

4. Discussion

This systematic review and meta-analysis provides robust evidence that the implementation of standardized nursing protocols in the PACU significantly enhances perioperative safety and efficiency. Compared with conventional care, evidence-based standardized protocols were associated with a statistically significant reduction in PACU length of stay, a marked decrease in the incidence of adverse events – including respiratory depression and hemodynamic instability – and substantial improvements in patient comfort and nursing satisfaction. These findings underscore the clinical imperative of transitioning from variable, experience-based nursing practices to structured, evidence-driven management models. The observed reduction in PACU length of stay, with an MD of 10.65 minutes (95% CI: −19.10 to −2.19), suggests that standardization streamlines the recovery trajectory. The mechanism driving this efficiency is likely twofold. First, the use of standardized handover checklists mitigates information transfer errors, preventing delays in clinical decision-making caused by missing data regarding anesthetic agents or intraoperative history.^[24] Second, the incorporation of stratified early warning systems – such as predictive algorithms for emergence agitation or respiratory scoring – facilitates proactive rather than reactive interventions, thereby preventing complications that would otherwise prolong hospitalization.^[25] Importantly, this efficiency gain was consistent across diverse surgical cohorts, including general, orthopedic, and gynecological surgery, suggesting the protocol’s broad applicability across surgical disciplines.^[26]

Regarding patient safety, the standardized protocols yielded a 63% reduction in the odds of adverse events (OR = 0.37; 95% CI: 0.23–0.60). This protective effect aligns with core principles of evidence-based nursing by reducing practice variability.^[27] By institutionalizing prophylactic measures – such as multimodal pain management pathways and distinct algorithms for airway obstruction – standardization ensures that critical safety steps are not omitted due to individual clinician oversight. For example, protocols mandating oxygen saturation monitoring every 3 minutes during the initial recovery phase, as opposed to the conventional 15-minute interval, allow for the rapid detection and reversal of hypoxemic events.^[28] The consistency of this finding across both randomized and observational studies further validates the intervention’s safety profile. Beyond clinical metrics, the analysis revealed significant improvements in patient-centered outcomes, including comfort scores and satisfaction with nursing care (OR = 3.18). These findings suggest that standardized protocols enhance the humanistic dimension of care.^[29] By explicitly integrating psychological support and structured communication with families into the nursing workflow, these protocols address the patient’s need for security and information during the vulnerable emergence phase.^[30] This aligns with modern perioperative guidelines, which advocate that systematic management should not only ensure physical safety but also optimize the subjective patient experience.^[31]

Despite these positive findings, substantial heterogeneity was observed, particularly regarding PACU length of stay (I² = 100%). Subgroup analyses failed to resolve this variance, indicating that it likely stems from clinical and methodological diversity rather than study design alone. Three primary factors likely contribute: first, the variability in the “standardized” interventions themselves, which ranged from simple checklists to complex clinical pathways^[32]; second, the disparity in baseline care quality across different institutions, where the marginal benefit of standardization may be lower in high-performing centers^[33]; and third, the intrinsic heterogeneity of the patient populations, whose physiological recovery profiles vary widely.^[34] Consequently, clinical implementation should not be rigid; rather, institutions should adapt core evidence-based principles to their specific local contexts and high-risk populations. Future research should prioritize dismantling the “black box” of standardized nursing to identify which specific components (e.g., handover checklists vs monitoring intervals) drive the observed benefits. Investigators should conduct large-scale, multicenter RCTs with uniform protocol definitions to minimize heterogeneity. Furthermore, research inquiries should expand to include cost-effectiveness analyses and the long-term impact of these protocols on nursing staff well-being, specifically looking at job satisfaction and teamwork dynamics. Finally, developing validated, PACU-specific quality assessment tools will be essential for the sustained auditing and refinement of these protocols.

5. Conclusion

In conclusion, this meta-analysis demonstrates that standardized PACU nursing protocols represent a superior standard of care compared with conventional practice. By systematizing critical workflows, these protocols effectively shorten recovery times, drastically reduce perioperative complications, and improve the patient experience. While the magnitude of benefit varies across settings, the direction of improvement is consistent. Healthcare administrators are strongly encouraged to integrate these evidence-based protocols into perioperative quality improvement initiatives, ensuring that nursing practice is defined by rigor, safety, and patient-centeredness.

Author contributions

Conceptualization: Yun Bai, Shuaiao Zhu, Xiaoya Chen.

Data curation: Yun Bai, Shuaiao Zhu.

Formal analysis: Yun Bai.

Software: Yun Bai, Shuaiao Zhu.

Resources: Shuaiao Zhu.

Supervision: Shuaiao Zhu.

Investigation: Xiaoya Chen.

Methodology: Xiaoya Chen.

Writing – original draft: Yun Bai, Shuaiao Zhu, Xiaoya Chen.

Writing – review & editing: Yun Bai, Shuaiao Zhu, Xiaoya Chen.